U.S. patent application number 13/370788 was filed with the patent office on 2012-06-07 for sensor node.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Miki HAYAKAWA, Norihiko Moriwaki, Norio Ohkubo, Satomi Tsuji, Kazuo Yano.
Application Number | 20120139750 13/370788 |
Document ID | / |
Family ID | 40087538 |
Filed Date | 2012-06-07 |
United States Patent
Application |
20120139750 |
Kind Code |
A1 |
HAYAKAWA; Miki ; et
al. |
June 7, 2012 |
SENSOR NODE
Abstract
There is disclosed a sensor node capable of transmitting and
receiving a large amount of data or data desired to be reliable
without missing data, while preventing battery exhaustion and
unnecessary compression of the transmission bandwidth. A name-tag
type sensor node includes a detector for detecting connection of an
external power supply. When the detector detects that the external
power is supplied, the name-tag type sensor node transmits and
receives a large amount of data, such as bulk transmission data, at
an increased frequency by means of a data selector, a communication
timing controller, and a wireless communication controller.
Alternatively, the name-tag type sensor node transmits and receives
the data desired to be reliable, such as rewriting data of
firmware.
Inventors: |
HAYAKAWA; Miki; (Cambridge,
MA) ; Moriwaki; Norihiko; (Hino, JP) ; Yano;
Kazuo; (Hino, JP) ; Tsuji; Satomi; (Kokubunji,
JP) ; Ohkubo; Norio; (Tokyo, JP) |
Assignee: |
Hitachi, Ltd.
Tokyo
JP
|
Family ID: |
40087538 |
Appl. No.: |
13/370788 |
Filed: |
February 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12153689 |
May 22, 2008 |
8138945 |
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13370788 |
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Current U.S.
Class: |
340/870.03 |
Current CPC
Class: |
H04Q 2209/88 20130101;
H04Q 2209/845 20130101; H04Q 2209/40 20130101; H04Q 9/00
20130101 |
Class at
Publication: |
340/870.03 |
International
Class: |
G08C 15/06 20060101
G08C015/06 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2007 |
JP |
JP2007-143642 |
Claims
1. A sensor node for measuring and transmitting physical
quantities, comprising: a controller for controlling the
measurement of the physical quantities by driving a plurality of
sensors; and a communication circuit for transmitting physical
quantity data obtained by the controller from the plurality of
sensors via wireless or wired communication, wherein each of the
sensors includes a plurality of infrared transceivers for detecting
that the sensor nodes face each other, and wherein the plurality of
infrared transceivers are mounted on the sensor node at different
angles, and wherein transmitters or receivers of the plurality of
infrared transceivers are operated in a time-sharing manner.
2. A sensor node for measuring and transmitting physical
quantities, comprising: a controller for controlling the
measurement of the physical quantities by driving a plurality of
sensors; and a communication circuit for transmitting physical
quantity data obtained by the controller from the plurality of
sensors via wireless or wired communication, wherein each of the
sensors includes a plurality of infrared transceivers for detecting
that the sensor nodes face each other, and wherein the plurality of
infrared transceivers are mounted on the sensor node at different
angles, and wherein the sensor node obtains information about the
direction of another sensor node which faces each other.
Description
CLAIM OF PRIORITY
[0001] This application is a Continuation of U.S. application Ser.
No. 12/153,689, filed May 22, 2008. Priority is claimed based on
U.S. application Ser. No. 12/153,689, filed on May 22, 2008, which
claims priority from Japanese patent application JP2007-143642,
filed May 30, 2007, the content of which is hereby incorporated by
reference into this application.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a business microscope
system for visualizing the state of an organization, and more
particularly to a sensor node which is a terminal for obtaining and
transmitting physical quantities in such a system.
[0003] Productivity improvement is an important issue for all kinds
of organizations. Many experimental trials are taking place to
improve work environments and to streamline operations. When
limited to organizations such as factories involved in assembly or
delivery operation, it is possible to objectively analyze the
performance by pursuing the movement track of parts or products.
However, with respect to white-collar organizations involved in
knowledge work activities such as clerical work, sales, and
planning in which goods and works are not directly connected, it is
difficult to evaluate such organizations by observing goods.
Primarily, the reason for forming an organization is that plural
persons work together to achieve large scale operations unable to
be done by an individual. Thus, decisions and agreements are
typically made by two or more persons in any kind of organization.
The decisions and agreements would depend on the relationship among
persons, and thus the productivity would depend on its success or
failure. Here, the relationship may be labeled, for example, as a
manager, a subordinate, or a friend. It may also include mutual
feelings such as like, dislike, confidence, or influence.
Communication is a very important tool for establishing a
face-to-face relationship. For this reason, the relationship could
be examined by obtaining records of communications.
[0004] One method of detecting face-to-face communication uses a
sensor network. The sensor network is a technology that is applied
to obtain and control a state, by terminals equipped with sensors
and a wireless communication circuit, which are attached to an
environment, objects, persons and the like to extract various types
of information from the sensors through wireless communication.
Physical quantities are obtained by the sensors for detecting such
communication. Examples of the physical quantity include infrared
radiation for detecting face-to-face communication state, voice for
detecting speech and environment, and acceleration for detecting
activity and movements of a person.
[0005] The business microscope system is a system that visualizes
the state of an organization by detecting the movements of persons
and the face-to-face communication from the physical quantities
obtained by sensors. That is, the business microscope system helps
to improve the organization.
[0006] The physical quantities obtained by sensors are important
for analyzing a face-to-face communication, in connection with the
time at which an event occurs and its context, as well as the
relationship between physical quantities obtained by different
sensors. If any data goes missing, it is difficult to accurately
evaluate the face-to-face communication. Thus, the data should be
continuously obtained as long as the terminal is attached.
[0007] Generally, there are two major factors that cause the
missing data obtained by the terminal of the sensor network. The
first involves the power supply. When the battery is exhausted and
changed, the power is interrupted during that time, and the
physical quantities are not obtained or communicated by the
sensors. The second involves the problem of communication. The
distance of wireless communication is limited. If a terminal and a
base station are separated at a certain distance or farther, it is
difficult to communicate with each other. Also, the communicable
distance is reduced under noisy environment, or by obstacles on the
communication path or other problems.
[0008] Technologies have been developed to perform sensing and
communication while charging a secondary battery incorporated in a
terminal, for continuous acquisition and communication of sensor
information, as disclosed in JP-A 2006-312010, JP-A 2004-178045,
and JP-A 2004-235965.
BRIEF SUMMARY OF THE INVENTION
[0009] In the above cited JP-A 2006-312010 and 2004-178045, it is
described that a terminal is generally operated by a built-in
secondary battery, or operated by an external power supply when
power is supplied from the outside. It is further described that
the built-in secondary battery is charged in parallel while the
communication operation is continued regardless of the presence or
absence of the external power supply. In the cited references, when
the external power supply is connected, only the destination is
changed to the external power supply. The communication content and
the communication frequency remain the same as in normal
operation.
[0010] For example, data for rewriting the firmware of a sensor
node has a size larger than that of the physical data obtained by
sensors, and may not be entirely used when only partial data is
missing. Transferring such data during battery operation poses
problems such as wastefully consuming power and compressing
communication bandwidth due to retransmission control.
[0011] The present invention aims at providing a sensor node
capable of measuring physical quantities, without increasing power
consumption during battery operation and without unnecessarily
compressing communication bandwidth, as well as preventing missing
data caused by the power supply and communication problems
described above.
[0012] The business microscope is assumed to be applied to an
office environment, in which physical quantities are obtained by
name-tag type sensor nodes. Each name-tag type sensor node does not
measure physical quantities during night hours when its wearer goes
home from the office. The name-tag type sensor node operates by a
built-in secondary battery when the wearer is in the office, and is
attached to a cradle or connected to an external power supply to
charge the secondary battery when the wearer is at home.
[0013] The inventors of the present application focused on the fact
that an external power supply unit for supplying power from the
outside to a name-tag type sensor node, and a base station for
communicating with the name-tag type sensor node, are provided on a
desk or in the vicinity thereof. Thus, the name-tag type sensor
node and the base station are close to each other above the desk in
which communication is stabilized. Further, during the period when
the name-tag type sensor node is supplied with power from the
outside, such as from a cradle attached thereto, it is very natural
that the name-tag type sensor node is not worn by a person. Thus,
the communication bandwidth is assumed to be unused during this
period.
[0014] When the power is supplied on the desk from the outside,
there is no need to consider the battery exhaustion, the
communication is stabilized, and the communication bandwidth is
unused. Because of these conditions, it is appropriate to transmit
and receive a large amount of data, or data desired to be
reliable.
[0015] The present invention is a name-tag type sensor node for
obtaining face-to-face communication. When it is detected that
power is supplied from the outside by connecting to an external
power supply or other means on a desk, the name tag type sensor
node shifts to a mode for transmitting and receiving a large amount
of data by increasing the communication frequency, or a mode for
transmitting and receiving data desired to be reliable.
[0016] The sensor node transfers a large amount of data or data
desired to be reliable, while preventing battery exhaustion and
unnecessary compression of communication bandwidth. In this way,
the sensor node can transmit and receive data without missing
data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1A to 1C are block diagrams showing a flow of
processes in a business microscope system;
[0018] FIGS. 2A and 2B are block diagrams showing the configuration
of a name-tag type sensor node which is a first embodiment, in the
entire business microscope system;
[0019] FIGS. 3A to 3E are external views of the name-tag type
sensor node according to the first embodiment;
[0020] FIGS. 4A to 4C are views showing the placement of infrared
transceiver modules in the name-tag type sensor node according to
the first embodiment;
[0021] FIG. 5 is a view showing the axes of triaxial acceleration
that are detected by the name-tag sensor node according to the
first embodiment;
[0022] FIG. 6 is a view showing the button operation and screen
transition of the name-tag type sensor node according to the first
embodiment;
[0023] FIG. 7 is a view showing an example of the configuration
between a cradle and the name-tag type sensor node according to the
first embodiment;
[0024] FIG. 8 is a view showing the connection relationship among a
battery for cradle CRDBATT, cradle CRD, and the name-tag type
sensor node according to the first embodiment;
[0025] FIG. 9 is a block diagram showing a specific example of the
hardware configuration of the name-tag type sensor node according
to the first embodiment;
[0026] FIG. 10 is a block diagram showing a specific example of the
hardware configuration of the cradle CRD for the name-tag type
sensor node according to the first embodiment;
[0027] FIG. 11 is a block diagram showing a specific example of the
hardware configuration of the battery for cradle according to the
first embodiment;
[0028] FIGS. 12A to 12F are views showing an operation sequence in
which the name-tag type sensor node according to the first
embodiment obtains and transmits physical quantities from
sensors;
[0029] FIGS. 13A to 13D are views showing a data flow and the
timing, in which data is transferred from the name-tag type sensor
node according to the first embodiment, to abase station, and then
transferred to a sensor net server SS;
[0030] FIG. 14 is a flowchart showing the process of the name-tag
type sensor node according to the first embodiment; and
[0031] FIGS. 15A to 15K are views showing the relationship of
operation timings when plural name-tag type sensor nodes according
to the first embodiment face each other.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Hereinafter a preferred embodiment of the present invention
will be described with reference to the accompanying drawings.
[0033] First, a business microscope system will be described to
clarify the position and function of a sensor node according to the
present invention. Here, business microscope is a system to observe
the state of a person by a sensor node worn by the person, and
display the relationship among persons as activities and evaluation
(performance) of an actual organization in a picture, in order to
improve the organization. The data obtained by the sensor node,
such as of face-to-face communication detection, activity and
movements, voice, is collectively referred to as dynamics data.
[0034] FIGS. 1A, 1B, 1C are diagrams showing the overall flow of
processes performed in a business microscope system which is an
embodiment of the present invention. The flow is divided into
several parts for illustrative convenience, but the processes shown
in the figures are performed in association with each other. Shown
here is a series of flows from the acquisition of organizational
dynamics data (BMA) by plural name-tag type sensor nodes (NNa to
NNj) to the display (MBF) of the relationships among persons as
organizational activities, together with the actual organizational
evaluation (performance).
[0035] The system performs the organizational dynamics data
acquisition (BMA), performance input (BMP), organizational dynamics
data collection (BMB), inter-data alignment (BMC), correlation
coefficient study (BMD), organizational activity analysis (BME),
and organizational activity display (BMF) in an appropriate order.
Incidentally, examples of devices for performing these processes,
as well as the configuration of the entire system including such
devices, will be described below with reference to FIGS. 2A and
2B.
[0036] First, the organizational dynamics data acquisition (BMA)
will be described with reference to FIG. 1A. A name-tag type sensor
node A (NNa) includes: sensors such as an acceleration sensor
(ACC), an infrared transceiver (TRIR), and a microphone (MIC); an
image screen (IRD) for displaying face-to-face communication
information obtained by the infrared transceiver; a user interface
(RTG) for inputting ratings; and a microcomputer and a wireless
transmission function that are not shown in the figures.
[0037] The acceleration sensor (ACC) detects the acceleration of
the name-tag type sensor node A (NNa), namely, the acceleration of
a person A (not shown) wearing the name-tag type sensor node A
(NNa). The infrared transceiver (TRIR) detects the facing state of
the name-tag type sensor node A (NNa), namely, the state in which
the name-tag type sensor node A (NNa) is facing the other name-tag
type sensor node. Incidentally, the state in which the name-tag
type sensor node A (NNa) is facing the other name-tag type sensor
node means that the person A wearing the name-tag type sensor node
A (NNa) is facing a person wearing the other name-tag type sensor
node. The microphone (MIC) detects the voice around the name-tag
type sensor node A (NNa).
[0038] The system of this embodiment includes plural name-tag type
sensor nodes (name-tag type sensor nodes A (NNa) to J (NNj)). Each
name-tag type sensor node is worn by each person. For example, the
name-tag type sensor node A (NNa) is worn by the person A, the
name-tag type sensor node B (NNb) is worn by a person B (not
shown). This is for the analysis of the relationships among
persons, as well as for the display of the performance of the
organization.
[0039] Incidentally, as with the name-tag type sensor node A (NNa),
the name-tag type sensor nodes B (NNb) to J (NNj) each include the
sensors, microcomputer, and wireless transmission function. In the
following description, when the description is given to all the
name-tag type sensor nodes A (NNa) to J (NNj) and when the name-tag
type sensor nodes may not be necessary to be distinguished from
each other, the name-tag type sensor nodes are simply referred to
as the name-tag type sensor node (NN).
[0040] The name-tag type sensor node (NN) performs sensing by the
sensors constantly (or repeatedly at a short interval). Then, the
name-tag type sensor node (NN) wirelessly transmits the obtained
data (sensing data) at a predetermined interval. The interval at
which the data is transmitted may be the same as the sensing
interval, or may be larger than the sensing interval. At this time,
the transmission data is added with the sensing time and the
identifier (ID) unique to the sensing name-tag type sensor node
(NN). The data is wirelessly transmitted in bulk to suppress power
consumption, so that the name-tag type sensor node (NN) worn by a
person is kept available for a long time. It is preferable that the
same sensing interval is given in all the name-tag type sensor
nodes (NN) for the subsequent analysis.
[0041] The performance input (BMP) is a process for inputting
values indicating performance. Here, the performance means a
subjective or objective evaluation that is determined based on
certain criteria. For example, a person who wears the name-tag type
sensor node (NN) inputs values of subjective evaluation
(performance) at a predetermined timing, based on certain criteria,
such as work achievement at this time, and contribution and
satisfaction to the organization. The predetermined timing may be,
for example, once per several hours, once a day, or the time at
which an event such as a meeting is completed. The person wearing
the name-tag type sensor node (NN) can input values of performance
by operating the name-tag type sensor node (NN), or by operating a
personal computer (PC) such as a client (CL). It is also possible
to input handwritten values to the PC later at a time. This
embodiment shows an example that the performance can be rated in
terms of health state (Health), mental state (Mental), and
motivation to study (Study). The input performance values are used
for studying the correlation coefficient. Thus, when the obtained
performance values are sufficient to conduct a certain degree of
study, additional value is not necessarily demanded.
[0042] The performance of the organization may be calculated from
the performance of an individual. The objective data such as sales
or cost, as well as the data already digitized such as
questionnaire results, may be periodically input as the
performance. When a numerical value is automatically obtained, such
as an error occurrence rate in the production management or other
fields, the obtained value may be automatically input as a
performance value.
[0043] The data wirelessly transmitted from each name-tag type
sensor node (NN) is collected in the organizational dynamics data
collection (BMB), and stored in a database. For example, a data
table is generated for each name-tag type sensor node (NN), namely,
for each person wearing the name-tag type sensor node (NN). The
collected data is classified based on the unique ID, and stored in
the data table in order of the sensing time. If the table is not
generated for each name-tag type sensor node (NN), it is necessary
to have a column for the ID information of the name-tag type sensor
node or the person, in the data table. Incidentally, a data table A
(DTBa) in FIG. 1A shows an example of a simplified data table.
[0044] Further, the performance value input in the performance
input (MBP) is stored in a performance database (PDB), together
with the time information.
[0045] In the inter-data alignment (BMC), data relating to
arbitrary two persons is aligned based on the time information to
compare the data relating to the two persons (namely, the data
obtained by the name-tag type sensor nodes (NN) worn by the
relevant persons). The aligned data is stored in a table. At this
time, of the data relating to the two persons, the data of the same
time is stored in the same record (line). The data of the same time
is two data pieces including the physical quantities detected by
the two name-tag type sensor nodes (NN) at the same time point.
When the data relating to the two persons does not include the data
of the same time, the data of the nearest time may be approximately
used as the data of the same time. In this case, the data of the
nearest time is stored in the same record. It is preferable that
the times of the data stored in the same record are adjusted, for
example, by the average value of the nearest time. Incidentally,
these data pieces are not necessarily stored in the table, and may
be stored in such a way that the data can be compared in
chronological order.
[0046] Incidentally, a combined table (CTBab) of FIG. 1A shows an
example of a simplified combination of a data table A (DTBa) and a
data table B (DTBb). However, the detail of the data table B (DTBb)
is not shown in the figure. The combined table (CTBab) includes the
acceleration, infrared, and voice data. However, it is also
possible to generate a combined table for each type of data, for
example, a combined table including only the acceleration data or a
combined table including only the voice data.
[0047] The content of the combined table is used as combined table
data BMCD1 and BMCD2 for the organizational activity analysis (BME)
and the correlation coefficient study (BMD) shown in FIGS. 1B and
1C.
[0048] In this embodiment, the correlation coefficient study (BMD)
is performed in order to calculate the relationship from the
organizational dynamics data and estimate the performance (FIG.
1B). First, the correlation coefficient is calculated using the
data of a certain period in the past. This process may be more
effective if the correlation coefficient is periodically
recalculated and updated using new data.
[0049] The following description is an example of the calculation
of the correlation coefficient from the acceleration data. However,
the correlation coefficient can also be calculated using the time
series data, such as the voice data, in place of the acceleration
data by the same procedure as described below.
[0050] Incidentally, in this embodiment, the correlation
coefficient study (BMD) is performed by an application server (AS)
(see FIG. 2B), which will be described below. However, the
correlation coefficient study (BMD) may actually be performed by a
device other than the application server (AS).
[0051] First, the application server (AS) sets a width T of data
used for the calculation of the correlation coefficient, in the
range from several days to several weeks. The application server
(AS) selects the data in this period.
[0052] Next, the application server (AS) performs an acceleration
frequency calculation (BMDA). The acceleration frequency
calculation (BMDA) is a process for obtaining a frequency from the
acceleration data aligned in chronological order. The frequency is
defined as the number of wave frequencies per second. In other
words, the frequency is an index of the intensity of the frequency.
However, Fourier transform is necessary for an accurate calculation
of the frequency, and the amount of calculation is increased.
Although the frequency may be accurately calculated using Fourier
transform, this embodiment uses a zero-cross value serving as the
frequency in order to simplify the calculation.
[0053] The zero-cross value is a count of the number of times the
value of the time series data in the certain period is zero. More
specifically, the zero-cross value is a count of the number of
times the time series data changes from a positive value to a
negative value or vice versa. For example, assuming that one cycle
is a period of time during which the acceleration value changes
from positive to negative and again from negative to positive. The
frequency per second can be calculated from the counted number of
zero-crosses. The frequency per second calculated as described
above can be used as the approximate frequency of acceleration.
[0054] Further, the name-tag type sensor node (NN) of this
embodiment is equipped with a triaxial acceleration sensor. Thus,
one zero-cross value is calculated by summing the zero-cross values
in three axis directions in the same period. In this way, the
pendulum motion is detected in particular in the left-and-right and
back-and-forth directions, able to be used as an index of the
intensity of the frequency.
[0055] As the "certain period" for which the zero-cross value is
calculated, a value larger than the interval of the continuous data
(namely, the original sensing interval) is set in the unit of
second or minute.
[0056] Further, the application server (AS) sets a window width w,
which is a time width larger than the zero-cross value and smaller
than the entire data width T. In the next step, the frequency
distribution and fluctuation are obtained in this window. Then, the
frequency distribution and fluctuation are calculated for each
window by moving the windows sequentially along the time axis.
[0057] At this time, when the window is moved across the same width
as the window width w, there is no data overlap between the
windows. As a result, a feature amount graph used in the subsequent
correlation coefficient calculation (BMDC) is a discrete graph.
Whereas when the window is moved in a width smaller than the window
width w, parts of the data in the windows overlap. As a result, the
feature amount graph used for the subsequent correlation
coefficient calculation (BMDC) is a continuous graph. The width by
which the window is moved may be set to an arbitrary value, by
considering the fact as described above.
[0058] Incidentally, in FIG. 1B, the zero-cross value is also
referred to as frequency. In the following description, the term
"frequency" is the concept including the zero-cross value. In other
words, in the following description, the term "frequency" may be
applied to the accurate frequency calculated by Fourier transform,
or to the approximate frequency calculated from the zero-cross
value.
[0059] Next, the application server (AS) performs an individual
feature amount extraction (BMDB). The individual feature amount
extraction (BMDB) is a process for extracting the feature amount of
an individual by calculating the frequency distribution and
frequency fluctuation of the acceleration in each window.
[0060] First, the application server (AS) obtains the frequency
distribution (namely, the intensity) (DB12).
[0061] In this embodiment, the frequency distribution is a
frequency at which the acceleration of each frequency occurs.
[0062] The frequency distribution of the acceleration reflects what
a person wearing the name-tag type sensor node (NN) does and how
long it takes. For example, the frequency of the acceleration is
different between when the person is walking and when writing
e-mail by a PC. In order to record a histogram of such an
acceleration history, the occurrence frequency of the acceleration
is obtained for each frequency.
[0063] At this time, the application server (AS) determines the
frequency assumed (or desired) to be maximum. Then the application
server (AS) divides the value from 0 to the determined maximum
value, into 32 segments. Then the application server (AS) counts
the number of acceleration data included in each of the divided
frequency ranges. In this way, the occurrence frequency of the
acceleration is calculated for each frequency, and is treated as
the feature amount. The same process is performed for each
window.
[0064] The application server (AS) calculates the "fluctuation for
each frequency" (DB11), in addition to the frequency distribution
of the acceleration. The fluctuation of frequency is the value
indicating how long the frequency of the acceleration is
continuously maintained.
[0065] The fluctuation for each frequency is an index of how long
the activity of a person is maintained. For example, suppose a
person walks for 30 minutes in an hour. The meaning of the activity
is different between the case where the person repeats a one minute
walk and a one-minute stop and the case where the person continues
to walk for 30 minutes after a 30-minute break. These activities
can be distinguished by calculating the fluctuation for each
frequency.
[0066] However, the magnitude of fluctuation largely changes
depending on the setting of criteria, namely, the range of
differences between two continuous values in which it is determined
that the value of the acceleration frequency is maintained.
Further, information about the dynamics of data, such as whether
the value changes a little or a lot, could be missing. For this
reason, in this embodiment, the entire range of the acceleration
frequency is divided into a predetermined division number. Here,
the entire range of the frequency corresponds to the range from the
frequency "0" to the maximum value of the frequency (see Step
DB12). The divided segments are used as the criteria for
determination whether the value is maintained or not. For example,
when the division number is 32, the entire range of the frequency
is divided into 32 segments.
[0067] For example, when the acceleration frequency at a certain
time t is in the ith segment and the acceleration frequency at the
next time t+1 is in the (i-1)th, ith, or (i+1)th segment, it is
determined that the value of the acceleration frequency is
maintained. On the other hand, when the acceleration frequency at
the time t+1 is not in the (i-1)th, ith, or (i+1)th segment, it is
determined that the value of the acceleration frequency is not
maintained. The number of times of determining that the value is
maintained is counted as the feature amount of the fluctuation. The
above process is performed for each window.
[0068] Similarly, the feature amounts of the fluctuation with the
division numbers 16, 8, and 4 are calculated, respectively. In this
way, by changing the division number in the calculation of the
fluctuation for each frequency, both small and large changes can be
reflected in any of the feature amounts.
[0069] If the entire range of the frequency is divided into 32
segments to pursue the transition of a certain frequency from a
segment i to an arbitrary segment j, 1024 types (the square of 32)
of transition patterns should be considered. As a result, the
calculation amount increases as the number of patterns increases.
In addition to this problem, the error is statistically significant
because the amount of data corresponding to one pattern is
reduced.
[0070] While on the other hand, when the feature amount is
calculated with the division numbers 32, 16, 8, and 4 as described
above, only 60 patterns should be considered. As a result, the
statistical reliability is increased. Another advantage is that, by
calculating the feature amount for several division numbers from
large to small, various transition patterns can be reflected in the
feature amounts.
[0071] The above description has focused on the example of
calculating the frequency distribution and fluctuation of the
acceleration. The application server (AS) can perform the same
process as described above for other data (for example, the voice
data) than the acceleration data. As a result, the feature amount
is calculated based on the obtained data.
[0072] As described above, the application server (AS) calculates
32 patterns of the frequency distribution and 60 patterns of the
fluctuation magnitude for each frequency, or 92 values in total.
The application server (AS) treats the values as the feature
amounts of the person A in the windows in the time frame (DB13).
Incidentally, the 92 feature amounts (x.sub.A1 to x.sub.A92) are
all independent.
[0073] The application server (AS) calculates the above feature
amounts based on the data transmitted from the name-tag type sensor
nodes (NN) of all the members belonging to the organization (or all
the members desired to be analyzed). Since the feature amounts are
calculated for each window, the feature amounts for one member can
be treated as a time series data by plotting the feature amounts in
order of the time of the window. Incidentally, the time of the
window can be determined according to an arbitrary rule. For
example, the time of the window may be the time at the center of
the window, or may be the time at the beginning of the window.
[0074] The feature amounts (x.sub.A1 to x.sub.A92) are the feature
amounts for the person A, which are calculated based on the
acceleration detected by the name-tag type sensor node (NN) worn by
the person A. Similarly, feature amounts (for example, x.sub.B1 to
x.sub.B92) for the other person (for example, person B) are
calculated based on the acceleration detected by the name-tag type
sensor node (NN) worn by the person B.
[0075] Next, the application server (AS) performs an
intercorrelation calculation (BMDC). The intercorrelation
calculation (BMDC) is a process for obtaining the intercorrelation
of the feature amounts for two persons. Suppose the two persons are
person A and person B.
[0076] A feature amount x.sub.A shown in the intercorrelation
calculation (BMDC) of FIG. 1B is a graph plotting the time-series
change of the feature amount of the person A. Similarly, a feature
amount x.sub.B shown in the intercorrelation calculation (BMDC) is
a graph of the feature amount of the person B.
[0077] At this time, the influence of the feature amount (for
example, x.sub.A1) of the person A on the feature amount (for
example, x.sub.A1) of the person B, is expressed as the function of
time .tau.:
[ Formula 1 ] R ( .tau. ) = 1 T ' .intg. 0 T ' { x A ( t ) - x A _
} { x B ( t ) - x B _ } t .intg. 0 T ' { x A ( t ) - x A _ } 2 t
.intg. 0 T ' { x B ( t ) - x B _ } 2 t ( T ' = T - .tau. .tau. = -
T .about. T ) ( 1 ) ##EQU00001##
where, [0078] x.sub.A1(t): the value of the feature amount x.sub.1
of the person A at the time t
[0079] x.sub.A1: the average value of the feature amount x.sub.1 of
the person A in the time range of 0 to T
[0080] The same calculation can be applied to the person B. Here, T
is the time width in which the data of the frequency exists.
[0081] That is, in the above formula, when R(.tau.) is peaked with
.tau.=.tau..sub.1, the activity of the person B at a certain time
is likely to be similar to the activity of the person A done before
.tau..sub.1 from that time. In other words, the feature amount
x.sub.B1of the person B is influenced after the time .tau..sub.1
has passed from the occurrence of the activity of the feature
amount x.sub.A1 in the person A.
[0082] It is possible to understand that the value .tau., at which
the peak appears, represents a type of the influence. For example,
it could be said that .tau. of less than a few seconds indicates
the influence of a face-to-face communication such as nodding,
whereas .tau. of several minutes to several hours indicates the
influence of an activity.
[0083] The application server (AS) applies the procedure of the
intercorrelation calculation to 92 patterns which is the number of
the feature amounts of the person A and the person B. Further, the
application server (AS) calculates the feature amounts for each
pair of the members belonging to the organization (or the members
desired to be analyzed), by the above described procedure.
[0084] The application server (AS) obtains plural feature amounts
of the organization, from the results obtained by the
intercorrelation calculation relating to the feature amounts. For
example, the time domain is divided into several periods, such as
within an hour, within a day, and within a week. The values for
each pair of persons are treated as the feature amounts (BMDD).
Then, the constants are determined as the feature amounts from the
results of the intercorrelation calculation. At this time, it is
also possible to use a method other than the method described
above. In this way, one organizational feature amount is obtained
from one intercorrelation calculation. When the number of
individual feature amounts is 92, the square of 92 for each pair,
namely, 8464 organizational feature amounts can be obtained. The
intercorrelation reflects the influence and relationship of the two
members belonging to the organization. For this reason, by using
the values obtained by the intercorrelation calculations as the
feature amounts of the organization, it is possible to treat the
organization, which is realized through human relationship, in a
quantitative manner.
[0085] The application server (AS) obtains the data of quantitative
evaluation of the organization (hereinafter referred to as
performances) from the performance database (PDB) as PDBD shown in
FIG. 1A (BMDE). As described below, the correlations between the
organizational feature amounts and the performances are calculated.
The performances may be calculated, for example, from the
achievements of an individual that each person declared, or the
results of subjective evaluation relating to human relationships
and the like in the organization. It is also possible to use the
financial evaluation of the organization, such as sales and loss,
as the performances. The performances are obtained from the
performance database (PDB) of the organizational dynamics data
collection (BMB), and processed together with the time information
at which the performances were evaluated. Here, the description
will be made on an example of using six indexes (p.sub.1 to
p.sub.6), such as sales, customer satisfaction, cost, error rate,
growth, and flexibility, as the performances of the
organization.
[0086] Next, the application server (AS) performs correlation
analysis between the organizational feature amounts and each of the
organizational performances (BMDF). However, the organizational
feature amounts are enormous and include unnecessary feature
amounts. Thus, the application server (AS) selects only effective
feature amounts by a stepwise method (BMDG). The application server
(AS) may also use a method other than the stepwise method for the
selection of the feature amounts.
[0087] Then, in the relationship between the selected
organizational feature amounts (X.sub.1 to X.sub.m) and each
organizational performance, the application server (AS) determines
a correlation coefficient A.sub.1 (a.sub.1 to a.sub.m) satisfying
the following formula:
[Formula 2]
p.sub.1=a.sub.1X.sub.1+a.sub.2X.sub.2+ . . . +a.sub.mX.sub.m
(2)
[0088] Incidentally, m is 92 in the example of FIG. 1B. This is
performed for p.sub.1 to p.sub.6 to determine A.sub.1 to A.sub.6
for p.sub.1 to p.sub.6, respectively. Here, the simplest linear
modeling is done. However, values x.sub.1, x.sub.2 and so on
determined by the non-linear mode, may be adopted in order to
increase the accuracy. It is also possible to use a method such as
a neural network.
[0089] Next, using the correlation coefficients A.sub.1 to A.sub.6,
the six performances are estimated from the acceleration data.
[0090] The organizational activity analysis (BME) shown in FIG. 1C
is a process for obtaining a relationship between arbitrary two
persons in the combined table, from the data such as the
acceleration, voice, and face-to-face communication, and then
calculating the performances of the organization.
[0091] In this way, it is possible to estimate the performances of
the organization in real time while obtaining data, and to present
the estimation to the user. If the estimation is unfavorable, it is
possible to encourage the user to change the behavior toward a
positive direction. In other words, it is possible to provide
feedback at a short cycle.
[0092] First, the calculation using the acceleration data will be
described. The procedures of acceleration frequency calculation
(EA12), individual feature amount extraction (EA13),
intercorrelation calculation between persons (EA14), and
organizational feature amount calculation (EA15) are the same as
those of the acceleration frequency calculation (BMDA), individual
feature amount extraction (BMDB), intercorrelation calculation
(BMDC), and organizational feature amount calculation (BMDD) in the
correlation coefficient study (BMD). Thus, their description will
be omitted. The organizational feature amounts (x.sub.1 to x.sub.m)
are calculated by these procedures.
[0093] Then, the application server (AS) obtains the organizational
feature amounts (x.sub.1 to x.sub.m) calculated in Step EA15, and
obtains the correlation coefficients (A.sub.1 to A.sub.6) for the
respective performances calculated by the correlation coefficient
study (BMD) as BMDD shown in FIG. 1B (EA16). Then, using the
obtained parameters, the application server (AS) calculates the
value of the index of each performance:
[Formula 3]
p.sub.1=a.sub.1x.sub.1+a.sub.2x.sub.2+ . . . +a.sub.mx.sub.m
(3)
[0094] This value is an estimation of the organizational
performance (EA17).
[0095] As described below, the latest values of the six indexes of
the organizational performances are balanced and displayed.
Further, the history of the value of one index is displayed as an
index estimation history in a time-series graph.
[0096] The distance between arbitrary persons, which is obtained
from the value of the intercorrelation between the persons (EK41),
is used for determining a parameter (organizational structure
parameter) to display the organizational structure. Here, the
distance between the persons is an index of the relationship
between the persons, and not the geographic distance. For example,
the stronger the relationship between the persons is (for example,
the stronger the intercorrelation between the persons), the shorter
the distance therebetween is. Further, grouping is performed based
on their distance between the persons (EK42) to determine a group
in the display.
[0097] The grouping is a process for generating pairs of persons
having close relationships with each other. That is, a pair of at
least two persons A and B particularly having a close relationship
is defined as one group. A pair of at least two persons C and D
having another close relationship is defined as one group. Then, a
group of these persons A, B, C, and D is defined as a large
group.
[0098] Next, the calculation based on the infrared data will be
described. The infrared data includes information about who meets
who and when it occurs. The application server (AS) analyzes the
face-to-face communication history by the infrared data (EI22).
Then the application server (AS) defines parameters for displaying
the organizational structure based on the face-to-face
communication history (EK43). At this time, it is also possible
that the application server (AS) calculates the distance between
arbitrary persons from the face-to-face communication history, and
defines a parameter based on the calculated distance. For example,
the distance between the persons is calculated to be shorter
(namely, their relationship is stronger) as the number of their
face-to-face communications is increased in a predetermined
period.
[0099] For example, the application server (AS) may determine the
parameters, in such a way that the total number of face-to-face
communications in one person is reflected in the size of the node,
the number of short-term face-to-face communications among persons
is reflected in the distance among nodes, and the number of
long-term face-to-face communications between arbitrary persons is
reflected in the thickness of the link. Here, the node is an image
displayed to indicate each person on a display (CLOD) of the client
(CL). The link is a line connecting two nodes. As a result, the
displayed node is larger as the relevant person has communicated
face-to-face with many persons until now, regardless of who they
are. The two nodes are positioned closer to each other as the
relevant two persons have frequently communicated face-to-face in
recent days. The two nodes are connected by a thicker link as the
relevant two persons have communicated face-to-face for a long
time.
[0100] Further, the application server (AS) can reflect the
attribute information of a user wearing the name-tag type sensor
node, in the display of the organizational structure. For example,
the color of the node indicating a person may be determined by the
age of the person. Also, the shape of the node may be determined
according to the title of the position.
[0101] Next, the calculation based on the voice data will be
described. As with the case of using the acceleration data
described above, the intercorrelation between persons can be
calculated using the voice data in place of the acceleration data.
However, it is also possible to extract a conversation feature
amount (EV33) by extracting a voice feature amount from the voice
data (EV32) and by analyzing the extracted feature amount together
with the communication data. The conversation feature amount is an
amount indicating, for example, tone of voice in conversation,
rhythm of dialogue, or conversation balance. The conversation
balance is an amount indicating whether one of two persons
monopolizes the conversation or the two persons share the
conversation. The conversation balance is extracted based on the
voices of the two persons.
[0102] For example, the application server (AS) may determine a
parameter of the display so that the conversation balance is
reflected in the angle between the nodes. More specifically, for
example, when two persons share the conversation, the nodes
indicating the persons may be displayed in parallel. When one of
the two persons monopolizes the conversation, the node indicating
the talking person may be displayed above the node of the other
person. It is also possible to display so that the stronger the
tendency that one person monopolizes the conversation, the larger
the angle between a line connecting the nodes indicating the two
persons and a reference line (namely, an angle .theta..sub.AB or
.theta..sub.CD in the example of the organizational structure
display (FC31) in FIG. 1C). Here, the reference line is, for
example, a line provided in the lateral direction of the display
(namely, in the horizontal direction). The reference line may not
be displayed on the display.
[0103] The organizational activity display (BMF) is a process for
generating an index balance display (FA11), index estimation
history (FB21), and organizational structure display (FC31) and the
like, from the organizational performance estimation and
organizational structure parameters calculated by the above
described processes. The generated data is displayed on the display
(CLOD) of the client (CL), or other display means.
[0104] An organizational activity (FD41) of FIG. 1C is an example
of an image displayed on the display (CLOD) of the client (CL).
[0105] In the example of FIG. 1C, the selected display period, and
the unit desired to be displayed or plural members are first
displayed. Here, the unit is an organization having plural members.
There may be displayed all the members belonging to one unit, or
plural members who are a part of the unit. In the example of FIG.
1C, the results of the analysis based on the conditions such as the
display period and the unit are displayed as three different
images.
[0106] The image of the index estimation history (FB21) is an
example of an estimation result history on the performance of
"growth". This makes it possible to analyze what activity of the
member benefits the organization, and what is effective to turn
from negative to positive, by comparing to the past activity
history.
[0107] The organizational structure display (FC31) visualizes the
states of the small groups that constitute the organization, the
role that each member actually has in the organization, the balance
between arbitrary members, and the like.
[0108] The index balance display (FA11) shows the balance of the
estimation of the specified six organizational performances. This
makes it possible to figure out the strengths and weaknesses of the
actual organization.
<Overall Configuration of the Business Microscope System>
[0109] Next, the hardware configuration of the business microscope
system of this embodiment will be described with reference to FIGS.
2A, 2B. FIGS. 2A, 2B are block diagrams showing the overall
configuration of a sensor network system that realizes the business
microscope system. The five arrows of different shape in FIGS. 2A,
2B indicate the time synchronization, associate, storage of
obtained sensing data, data flow for data analysis, and control
signal.
[0110] The business microscope system includes a name-tag sensor
node (NN), a base station (GW), a sensor network server (SS), an
application server (AS), and a client (CL). Each of the functions
is realized by hardware, software, or the combination thereof. The
function block is not necessarily associated with a hardware
entity.
[0111] FIG. 2A shows the configuration of the name-tag type sensor
node (NN) which is an example of a sensor node. The name-tag type
sensor node (NN) is equipped with various sensors, including plural
infrared transceivers (TRIR1 to TRIR4) for detecting the
face-to-face communication state; a triaxial acceleration sensor
(ACC) for detecting the activity of a wearer, a microphone (MIC)
for detecting the speech of the wearer as well as the sound around
the wearer, luminance sensors (LS1F, LS1B) for detecting the back
and front of the name-tag type sensor node, and a temperature
sensor (THM). It should be understood that these sensors are
examples and other sensors may be used for detecting the
face-to-face communication state and activity of the wearer.
[0112] In this example, the name-tag type sensor node (NN) includes
four infrared transceivers. The infrared transceivers (TRIR1 to
TRIR4) continue to periodically transmit terminal information
(TRMD) which is the unique identification information of the
name-tag type sensor node (NN), in the front direction. When a
person wearing the other name-tag type sensor node (NNm) is
positioned substantially in front (for example, in front or
diagonally in front), the name-tag type sensor node (NN) and the
other name-tag type sensor node (NNm) exchange their terminal
information (TRMD) by infrared radiation.
[0113] Thus, it is possible to record who meets who.
[0114] Each infrared transceiver is generally formed by a
combination of an infrared emitting diode for infrared
transmission, and an infrared phototransistor. An infrared ID
transmitter IrID generates its own ID, TRMD, and transfers to the
infrared emitting diode of the infrared transceiver module. In this
example, the same data is transmitted to plural infrared
transceiver modules, and then all the infrared emitting diodes are
lighted at the same time. Of course, it is also possible to output
independent timings and different data, respectively.
[0115] Further, the data received by the infrared phototransistors
of the infrared transceivers TRIR1 to TRIR4, is ORed by a logical
sum circuit (IROR). In other words, when the ID is received by at
least one of the infrared receivers, it is recognized by the
name-tag type sensor node as an ID. Of course, it is also possible
to have plural ID receiving circuits independently. In this case,
the transmission and reception state can be provided for each of
the infrared transceiver modules. For example, it is possible to
obtain additional information about the direction of the other
facing name-tag type sensor node.
[0116] Physical quantity data SENSD detected by the sensors is
stored in a memory unit STRG by a sensor data storage controller
(SDCNT). The physical quantity data is converted to a transmission
packet by a wireless communication controller TRCC, and is
transmitted to the base station GW by a transceiver unit TRSR.
[0117] At this time, a communication timing controller TRTMG
generates a timing for extracting the physical quantity data SENSD
from the memory unit STRG and wirelessly transmitting the data. The
communication timing controller TRTMG has plural time bases to
generate plural timings.
[0118] Examples of the data stored in the memory unit are a
past-accumulated physical quantity CMBD, and data FMUD for updating
the firmware which is an operation program of the name-tag type
sensor node, in addition to the physical quantity data SENSD
currently detected by the sensors.
[0119] The name-tag type sensor node (NN) of this example detects
the connection of an external power supply (EPOW) by an external
power detection circuit (PDET), and generates an external power
detection signal (PDETS). The external power detection signal
(PDETS) is used in a time base selector (TMGSEL) to switch the
transmission timing generated by the timing controller (TRTMG). The
external power detection signal (PDETS) is also used in a data
selector (TRDSEL) to switch the data to be wirelessly transmitted.
This configuration is specific to this example. FIG. 2A shows an
example of the configuration in which the time base selector TMGSEL
switches the transmission timing between a time base 1 (TB1) and a
time base 2 (TB2) by the external power detection signal PDETS, and
in which the data selector TRDSEL switches the data to be
communicated among the physical quantity data SENDSD obtained by
the sensors, the past-accumulated physical quantity data CMBD, and
the firmware update data FIRMUPD, by the external power detection
signal PDETS.
[0120] The luminance sensors (LS1F, LS1B) are mounted on the front
and back of the name-tag type sensor node (NN), respectively. The
data obtained by the luminance sensors LS1F and LS1B is stored in
the memory unit STRG by a sensor data storage controller SDCNT. At
the same time, the obtained data is compared by a reverse detection
unit (FBDET). When the name tag is properly worn, the front
luminance sensor LS1F receives incoming light. The back luminance
sensor LS1B is positioned between the main body of the name-tag
type sensor node and the wearer, receiving no incoming light. At
this time, the luminance detected by LS1F is larger than the
luminance detected by LS1B. On the other hand, when the name-tag
type sensor node is reversed, LS1B receives incoming light. At this
time, the luminance detected by LS1B is larger than the luminance
detected by LS1F facing the wearer's side because LS1F faces the
wearer.
[0121] Here, the luminance detected by LS1F and the luminance
detected by LS1B are compared by the reverse detection unit FBDET
in order to detect that the name-tag type sensor node is reversed
and incorrectly worn. When a reverse is detected by FBDET, a
speaker SP generates a warning sound to notify the wearer.
[0122] The microphone (MIC) obtains voice information. From the
voice information it is possible to know, for example, that the
surrounding environment is "noisy" or "quiet". Further, by
obtaining and analyzing the voices of persons, it is possible to
analyze the face-to-face communication, such as whether the
communication is active or inactive, the conversation is
monopolized or shared, and the speakers are angry or smile.
Further, even if the infrared transceivers TRIR do not detect the
face-to-face communication state due to the standing positions of
the persons or other reasons, it is possible to compensate by the
voice information and the acceleration information.
[0123] The voice obtained from the microphone MIC is provided as a
voice waveform and as a signal integrated by an integrating circuit
AVG. The integrated signal represents the energy of the obtained
voice.
[0124] The triaxial acceleration sensor (ACC) detects the
acceleration of the node, namely, the movement of the node. Thus,
it is possible to analyze the intensity of the activity of the
person wearing the name-tag type sensor node, as well as the action
such as walking, from the acceleration data. Further, by comparing
the acceleration values detected by plural name-tag type sensor
nodes, it is possible to analyze the activation level of the
communication between the persons wearing the name-tag type sensor
nodes, the mutual rhythm, and the intercorrelation or other
data.
[0125] In the name-tag type sensor node of this example, the data
obtained by the triaxial acceleration sensor ACC is stored in the
memory unit STRG by the sensor data storage controller SDCNT. At
the same time, the orientation of the name tag is detected by an
up/down detection circuit UDDET. This uses the fact that the
triaxial acceleration sensor detects two types of acceleration,
which are observed as dynamic acceleration change in the wearer's
movement and as static acceleration of the Earth's gravity.
[0126] The display device LCDD displays the personal information
such as the department and name of the wearer when wearing the
name-tag type sensor node on the chest. In other words, the
name-tag type sensor node acts as a name tag. On the other hand,
when the wearer holds the name-tag type sensor node in the hand and
turns the display device LCDD toward the wearer, the name-tag type
sensor node is upside down. At this time, the content displayed on
the display device LCDD, as well as the button function are
switched by an up/down detection signal UDDETS generated by the
up/down detection circuit UDDET. In this example, the information
displayed on the display device LCDD is switched between the
analysis results of the infrared activity analysis (ANA) that is
generated by a display controller DISP, and the name tag display
DNM, based on the value of the un/down detection signal UDDETS.
[0127] The infrared radiation is exchanged between the nodes by
their transceivers (TRIR), in order to detect whether the name-tag
type sensor node is facing the other name-tag type sensor node,
namely, whether a person wearing the name-tag type sensor node is
facing a person wearing the other name-tag type sensor node. Thus,
it is preferable that the name-tag type sensor nodes are worn in
the front portion of the persons. As described above, the name-tag
type sensor node further includes the sensor such as the
acceleration sensor (ACC). The process of sensing in the name-tag
type sensor node corresponds to the organizational dynamics data
acquisition (BMA) in FIG. 1A.
[0128] There are often plural name-tag type sensor nodes, each
connected to each nearby base station (GW) to form a personal area
network (PAN).
[0129] The temperature sensor (THM) of the name-tag type sensor
node (NN) obtains temperature of the location of the name-tag type
sensor node. The luminance sensor (LS1F) obtains luminance in the
front direction or other direction of the name-tag type sensor node
(NN). In this way, it is possible to record the surrounding
environment. For example, the movement of the name-tag type sensor
node (NN) from a certain place to another place can be found based
on the temperature and the luminance.
[0130] The name-tag type sensor node includes buttons 1 to 3 (BTN1
to BTN3), display device (LCDD), speaker (SP) and the like, as an
input/output device for the wearer.
[0131] The memory unit (STRG) includes, in particular, a hard disc,
and a nonvolatile memory device such as a flash memory. The memory
unit (STRG) stores terminal information (TRMT) which is the unique
identification number of the name-tag type sensor node (NN),
interval of sensing, and operation setting (TRMA) such as the
content output to the display. In addition, the memory unit (STRG)
can temporarily store data, and is used for storing the sensing
data.
[0132] The communication timing controller (TRTMG) is a clock for
maintaining time information and updating the time information at a
predetermined interval. The time information is periodically
corrected by time information GWCSD transmitted from the base
station (GW), in order to prevent the time lag between the time
information and that of the other name-tag type sensor node.
[0133] The sensor data storage controller (SDCNT) manages the
obtained data by controlling the sensing interval and the like of
the sensors according to the operation setting (TRMA) stored in the
memory unit (STRG).
[0134] The time synchronization obtains the time information from
the base station (GW) and corrects the clock. The time
synchronization may be performed immediately after an associate
operation described below, or may be performed in response to a
time synchronization command transmitted from the base station
(GW).
[0135] The wireless communication controller (TRCC) is involved in
the data transmission and reception, controlling the transmission
interval and converting the data into a data format appropriate for
wireless transmission and reception. The wireless communication
controller (TRCC) may include a wired communication function
instead of wireless, if necessary. The wireless communication
controller (TRCC) sometimes performs congestion control so that the
transmission timing does not overlap with the transmission timing
of the other name-tag type sensor node (NN).
[0136] The associate (TRTA) transmits a request TRTAQ to form a
personal network area (PAN) with the base station (GW) shown in
FIG. 2B, and receives a response TRTAR to the request. Thus, the
base station (GW) to which the data should be transmitted is
determined. The associate (TRTA) is performed when the power of the
name-tag type sensor node (NN) is turned on, and when the
transmission/reception with the base station (GW) is stopped due to
movement of the name-tag type sensor node (NN). As a result of the
associate (TRTA), the name-tag type sensor node (NN) is associated
with the base station (GW) located nearby so that the wireless
signal reaches from the name-tag type sensor node (NN).
[0137] The transceiver unit (TRSR) includes an antenna to transmit
and receive wireless signals. The transceiver unit (TRSR) can also
transmit and receive using a connector for wired communication, if
necessary. The data TRSRD is transmitted and received between the
transceiver unit TRSR and the base station (GW) through the
personal area network (PAN).
[0138] The base station (GW) shown in FIG. 2B has a function of
intermediating between the name-tag type sensor node (NN) and the
sensor network server (SS). By considering the wireless range,
plural base stations (GW) are provided so as to cover areas such as
living room and work place.
[0139] The base station (GW) includes a transceiver unit (BASR), a
memory unit (GWME), a clock (GWCK), and a controller (GWCO).
[0140] The transceiver unit (BASR) receives wireless signals from
the name-tag type sensor node (NN), and performs wired or wireless
transmission to the base station (GW). Further, the transceiver
unit (BASR) includes an antenna for receiving wireless signals.
[0141] The memory unit (GWME) includes a hard disc, and a
nonvolatile memory device such as a flash memory. The memory unit
(GWME) stores at least operation setting (GWMA), data format
information (GWMF), terminal management table (GWTT), and base
station information (GWMG). The operation setting (GWMA) includes
the information about the operation method of the base station
(GW). The data format information (GWMF) includes the information
about the data format for data communication as well as the
information about the tag to be added to the sensor data. The
terminal management table (GWTT) includes the terminal information
(TRMT) of the children name-tag type sensor nodes (NN) in which the
association is actually established, and the local IDs provided to
manage the name-tag type sensor nodes (NN). The base station
information (GWMG) includes the information such as the address of
the own base station (GW). Further, the memory unit (GWME)
temporarily stores the updated firmware (GWTF) of the name-tag type
sensor node.
[0142] The memory unit (GMWE) may also store programs to be
executed by a central processing unit CPU (not shown) within the
controller (GWCO).
[0143] The clock (GWCK) maintains time information. The time
information is updated at a predetermined interval. More
specifically, the time information of the clock (GWCK) is corrected
by the time information obtained from an NTP (Network Time
Protocol) server at a predetermined interval.
[0144] The controller (GWCO) includes the CPU (not shown). The CPU
executes the programs stored in the memory unit (GWME) to manage
the acquisition timing of sensing data sensor information, the
processing of the sensor data, the transmission/reception timing to
the name-tag type sensor node (NN) as well as the sensor network
server (SS), and the time synchronization timing. More
specifically, the CPU executes the programs stored in the memory
unit (GWME) to perform the processes of wireless communication
control/communication control (GWCC), data format conversion
(GWDF), associate (GWTA), and time synchronization management
(GWCD).
[0145] The wireless communication control/communication control
(GWCC) controls the timing of wireless or wired communication with
the name-tag type sensor node (NN) and the sensor network server
(SS). Further, the wireless communication control/communication
control (GWCC) classifies the type of received data. More
specifically, the wireless communication control/communication
control (GWCC) identifies whether the received data is general
sensing data, data for an association operation, or a response of
the time synchronization or others, from the header portion of the
data. Then the wireless communication control/communication control
(GWCC) passes these data pieces to the appropriate functions,
respectively.
[0146] Incidentally, the wireless communication
control/communication control (GWCC) performs the data format
conversion (GWDF). More specifically, the wireless communication
control/communication control (GWCC) refers to the data format
information (GWMF) stored in the memory unit (GWME), converts the
data to an appropriate format for transmission/reception, and adds
the tag information for indicating the type of the data.
[0147] The associate (GWTA) transmits the response TRTAR to the
associate request TRTAQ transmitted from the name-tag type sensor
node (NN), and transmits the local ID assigned to the name-tag type
sensor node (NN). Once an association is established, the associate
(GWTA) performs a terminal management information correction (GWTF)
to correct the terminal management table (GWTT).
[0148] The time synchronization management (GWCD) controls the
interval and timing at which the time synchronization is performed,
and issues an instruction to perform the time synchronization. It
is also possible that the sensor network server (SS) performs the
time synchronization management (GWCD) and transmits the
instruction to all the base stations (GW) in the system, which will
be described below.
[0149] The time synchronization (GWCS) is connected to the NTP
server (TS) on the network to request and obtain time
information.
[0150] The time synchronization (GWCS) corrects the clock (GWCK)
based on the obtained time information. Then, the time
synchronization (GWCS) transmits the time synchronization
instruction and the time information (GWCSD), to the name-tag type
sensor node (NN).
[0151] The sensor network server (SS) of FIG. 2B manages the data
collected from all the name-tag type sensor nodes (NN). More
specifically, the sensor network server (SS) stores the data
transmitted from the base station (GW) into the database, while
transmitting the sensing data based on the requests from the
application server (AS) and the client (CL). Further, the sensor
network server (SS) receives a control command from the base
station (GW), and transmits the result obtained by the control
command to the base station (GW).
[0152] The sensor network server (SS) includes a transceiver unit
(SSSR), a memory unit (SSME), and a controller (SSCO). The sensor
network server (SS) should also have a clock when performing the
time synchronization management (GWDC).
[0153] The transceiver unit (SSSR) performs data transmission and
reception with the base station (GW), the application server (AS),
and the client (CL). More specifically, the transceiver unit (SSSR)
receives the sensing data transmitted from the base station (GW),
and transmits the sensing data to the application server (AS) or
the client (CL).
[0154] The memory unit (SSME) includes a hard disc, and a
nonvolatile memory device such as a flash memory. The memory unit
(SSME) stores at least performance database (SSMR), data format
information (SSMF), sensing database (SSDB), and terminal
management table (SSTT). The memory unit (SSME) may also store
programs to be executed by a CPU (not shown) of the controller
(SSCO). Further, the memory unit (SSME) temporarily stores the
updated firmware (GWTF) of the name-tag type sensor node, which was
once stored in a terminal firmware registration unit (TFI).
[0155] The performance database (SSMR) is a database for storing
evaluations (performances) of the organization and individuals,
which are input from the name-tag type sensor nodes (NN) or from
the existing data, together with the time data. The performance
database (SSMR) is the same as the performance database (PDB) of
FIG. 1A. The performance data is input from a performance input
unit (MRPI).
[0156] The data format information (SSMF) includes a data format
for communication, a method for separating the sensing data with a
tag added in the base station (GW) and for storing in the database,
and a method for responding to requests for data. As described
below, the communication controller (SSCC) refers to the data
format information (SSMF), typically after data reception and
before data transmission, in order to perform data format
conversion (SSDF) and data distribution (SSDS).
[0157] The sensing database (SSDB) is a database for storing the
sensing data obtained by the name-tag type sensor nodes (NN),
information of the name-tag type sensor nodes (NN), and information
of the base stations (GW) through which the sensing data is
transmitted from the name-tag type sensor nodes (NN), and the like.
Columns are generated for each of the data elements such as
acceleration and temperature to manage the data. It is also
possible to generate tables for each of the data elements. In both
cases, all the data is managed in association with the terminal
information (TRMT) which is the ID of the obtained name-tag type
sensor node (NN), and the information about the obtained time.
[0158] The terminal management table (SSTT) is a table containing
information about which name-tag type sensor node (NN) is actually
under the control of which base station (GW). When another name-tag
type sensor node (NN) is added to the base station (GW), the
terminal management table (SSTT) is updated.
[0159] The controller (SSCO) includes the central processing unit
CPU (not shown) to control the transmission/reception of sensing
data, and control the reading/writing of sensing data from/to the
database. More specifically, the CPU executes the programs stored
in the memory unit (SSME) to perform the processes of communication
control (SSCC), terminal management information correction (SSTF),
and data management (SSDA).
[0160] The communication control (SSCC) controls the timing of
wired or wireless communication with the base station (GW), the
application server (AS), and the client (CL). Further, as described
above, the communication control (SSCC) converts the format of the
data to be transmitted and received, to the data format in the
sensor network server (SS), or to the data format specific to each
communication target, based on the data format information (SSMF)
stored in the memory unit (SSME). Then, the communication control
(SSCC) reads the header portion indicating the type of the data,
and distributes the data to the corresponding process. More
specifically, the received data is transferred to the data
management (SSDA), and the command for correcting the terminal
management information is transferred to the terminal management
information correction (SSTF). The destination of the transmission
data is determined to be the base station (GW), the application
server (AS), or the client (CL).
[0161] The terminal management information correction (SSTF)
receives the command from the base station (GW) to correct the
terminal management information, and updates the terminal
management table (SSTT).
[0162] The data management (SSDA) manages the correction,
acquisition, and addition of the data in the memory unit (SSME).
For example, the data management (SSDA) stores each element of the
sensing data into the appropriate column of the database based on
the tag information. When the sensing data is read from the
database, the data management (SSDA) performs processes such as
selecting necessary data based on the time information and the
terminal information, and sorting the data in order of time.
[0163] The sensor network server (SS) receives data through the
base station (GW). Then, the data management (SSDA) classifies the
received data, and stores in the performance database (SSMR) and in
the sensing database (SSDB). This corresponds to the organizational
dynamics data collection (BMB) in FIG. 1A.
[0164] The application server (AS) shown in FIG. 2B analyzes and
processes the sensing data. An analysis application is activated
upon request from the client (CL), or automatically at a specified
time. The analysis application transmits a request to the sensor
network server (SS) and obtains necessary sensing data. Further,
the analysis application analyzes the obtained data, and then
transmits the analyzed data to the client (CL). It is also possible
that the analysis application stores the analyzed data directly to
an analysis database.
[0165] The application server (AS) includes a transceiver unit
(ASSR), a memory unit (ASME), and a controller (ASCO).
[0166] The transceiver unit (ASSR) performs the data transmission
and reception with the sensor network server (SS) and the client
(CL). More specifically, the transceiver unit (ASSR) receives a
command transmitted from the client (CL), and transmits a data
acquisition request to the sensor network server (SS). Further, the
transceiver unit (ASSR) receives the sensing data from the sensor
network server (SS), and transmits analyzed data to the client
(CL).
[0167] The memory unit (ASME) includes a hard disc, and an external
memory device such as a memory or an SD card. The memory unit
(ASME) stores the setting conditions for analysis and the analyzed
data. More specifically, the memory unit (ASME) stores a display
condition (ASMJ), analysis algorithm (ASMA), analysis parameter
(ASMP), terminal information-name (ASMT), analysis database (ASMD),
correlation coefficient (ASMS), and combined table (CTB).
[0168] The display condition (ASMJ) temporarily stores conditions
for display requested from the client (CL).
[0169] The analysis algorithm (ASMA) stores programs for analysis.
The appropriate program is selected in response to the request from
the client (CL). The analysis is performed by the selected
program.
[0170] The analysis parameter (ASMP) stores, for example,
parameters for feature amount extraction. When the parameters are
changed in response to the request from the client (CL), the
analysis parameter (ASMP) is rewritten.
[0171] The terminal information-name (ASMT) is a comparative table
of the ID of a terminal, and the name and attribute or other
information of a person wearing the terminal. Upon request from the
client (CL), the name of the person is added to the terminal ID of
the data received from the sensor network server (SS). When only
data of a person corresponding to a certain attribute is obtained,
the name of the person is converted to the terminal ID and a data
acquisition request is transmitted to the sensor network server
(SS), with reference to the terminal information-name (ASMT).
[0172] The analysis database (ASMD) is a database for storing the
analyzed data. The analyzed data may be temporarily stored before
transmission to the client (CL). It is also possible that a large
amount of analyzed data is stored so that the analyzed data can be
freely obtained in bulk. When the data is transmitted to the client
(CL) while being analyzed, there is no need to use the analysis
database (ASMD).
[0173] The correlation coefficient (ASMS) stores correlation
coefficients determined by the correlation coefficient study (BMD).
The correlation coefficient (ASMS) is used for the organizational
activity analysis (BME).
[0174] The combined table (CTB) is a table for storing data
relating to plural name-tag type sensor nodes aligned by the
inter-data alignment (BMC).
[0175] The controller (ASCO) includes a central processing unit CPU
(not shown) to control the data transmission/reception and to
analyze the sensing data. More specifically, the CPU (not shown)
executes the programs stored in the memory unit (ASME) to perform
communication control (ASCC), analysis condition setting (ASIS),
data acquisition request (ASDR), inter-data alignment (BMC),
correlation coefficient study (BMD), and organizational activity
analysis (BME), and terminal information-user reference (ASDU), or
other processes.
[0176] The communication control (ASCC) controls the timing of
wired or wireless communication with the sensor network server (SS)
and the client (CL). Further, the communication control (ASCC)
converts the format of the data, and distributes the data to
appropriate destinations according to data types.
[0177] The analysis condition setting (ASIS) receives analysis
conditions set by a user (US) through the client (CL), and stores
the received analysis conditions into the memory unit (ASME).
Further, the analysis condition setting (ASIS) generates a command
to request data to the server, and transmits a data acquisition
request (ASDR).
[0178] The data transmitted from the server based on the request of
the analysis condition setting (ASIS), is aligned by the inter-data
alignment (BMC) based on the time information of the data relating
to arbitrary two persons. This is the same as the process of the
inter-data alignment (BMC) in FIG. 1A.
[0179] The correlation coefficient study (BMD) is a process
corresponding to the correlation coefficient study (BMD) in FIG.
1B. The correlation coefficient study (BMD) is performed using the
analysis algorithm (ASMA). The result is stored in the correlation
coefficient (ASMS).
[0180] The organizational activity analysis (BME) is a process
corresponding to the organizational activity analysis (BME) in FIG.
1C. The organizational activity analysis (BME) is performed by
obtaining the stored correlation coefficient (ASMS) and using the
analysis algorithm (ASMS). The results of the analysis are recorded
in the analysis database (ASMD).
[0181] The terminal information-user reference (ASDU) converts the
data managed with the terminal information (ID) into the name or
other designation of the user of each terminal, based on the
terminal information-name (ASMT). The terminal information-user
reference (ASDU) may also provide additional information such as
the title and position of the user. The terminal information-user
reference (ASDU) may be omitted, if not necessary.
[0182] The client (CL) shown in FIG. 2B interfaces with the user
(US) for inputting and outputting data. The client (CL) includes an
input/output unit (CLIO), a transceiver unit (CLSR), a memory unit
(CLME), and a controller (CLCO).
[0183] The input/output unit (CLIO) serves as an interface with the
user (US). The input/output unit (CLIO) includes a display (CLOD),
a keyboard (CLIK), and a mouse (CLIM) and the like. It is also
possible to connect another input/output device to an external
input/output (CLIU) according to the necessity.
[0184] The display (CLOD) is an image display device such as a CRT
(Cathode-Ray Tube) or a liquid crystal display. The display (CLOD)
may include a printer and the like.
[0185] The transceiver unit (CLSR) performs the data transmission
and reception with the application server (AS) or the sensor
network server (SS). More specifically, the transceiver unit (CLSR)
transmits the analysis conditions to the application server (AS)
and receives the analysis results.
[0186] The memory unit (CLME) includes a hard disc, and an external
memory device such as a memory or an SD card. The memory unit
(CLME) stores information necessary for drawing, such as analysis
condition (CLMP) and drawing setting information (CLMT). The
analysis condition (CLMP) stores the conditions set by the user
(US), such as the number of members to be analyzed and the
selection of analysis method. The drawing setting information
(CLMT) stores the information about the drawing position, namely,
what is plotted and which part of the drawing. Further, the memory
unit (CLME) may also store programs to be executed by a CPU (not
shown) of the controller (CLCO).
[0187] The controller (CLCO) includes the CPU (not shown) to
perform communication control, input of the analysis conditions
from the user (US), drawing of the analysis results to be presented
to the user (US) and the like. More specifically, the CPU executes
the programs stored in the memory unit (CLME) to perform
communication control (CLCC), analysis condition setting (CLIS),
drawing setting (CLTS), and organizational activity display (BMF),
or other processes.
[0188] The communication control (CLCC) controls the timing of
wired or wireless communication with the application server (AS) or
the sensor network server (SS). Further, the communication control
(CLCC) converts the format of the data, and distributes the data to
appropriate destinations according to data types.
[0189] The analysis condition setting (CLIS) receives analysis
conditions specified by the user (US) through the input/output unit
(CLIO), and stores in the analysis condition (CLMP) of the memory
unit (CLME). Here, the period of the data used for analysis,
member, type of analysis, and parameter for analysis, or other
conditions are set. The client (CL) requests an analysis by
transmitting the settings to the application server (AS), while
performing the drawing setting (CLTS).
[0190] The drawing setting (CLTS) calculates a method to display
analysis results based on the analysis condition (CLMP), as well as
plotting positions. The results of this process are stored in the
drawing setting information (CLMT) of the memory unit (CLME).
[0191] The organizational activity display (BMF) generates charts
by plotting the analysis results obtained from the application
server (AS). For example, the organizational activity display (BMF)
plots a display like a radar chart, a time-series graph, and an
organizational structure display, as shown in the organizational
activity display (BMF) of FIG. 1C. At this time, the organizational
activity display (BMF) also displays the attribute such as the name
of the displayed person, if necessary. The generated display result
is presented to the user (US) through the output device such as the
display (CLOD). The user (US) can finely adjust the display
position by an operation such as drag and drop.
<External Appearance of the Business Microscope Name-Tag Type
Sensor Node>
[0192] FIGS. 3A to 3E are external views showing an example of the
configuration of the name-tag type sensor node. The name-tag type
sensor node has a strap attachment portion NSH to which a neck
strap or a clip is attached. The name-tag type sensor node is worn
on the neck or chest of the user.
[0193] The surface with the strap attachment portion NSH is defined
as the top side, and the opposite surface as the bottom side.
Further, when the name-tag type sensor node is worn, the surface
facing the other person is defined as the front side and the
opposite surface as the back side. Still further, the surface
positioned on the left side seen from the front side of the
name-tag type sensor node is defined as the left side, and the
surface opposite to the left side as the right side. Thus, FIG. 3A
is a top view, FIG. 3B is a front view, FIG. 3C is a bottom view,
FIG. 3D is a back view, and FIG. 3E is a left side view.
[0194] As shown in the front view of FIG. 3B, a liquid crystal
display device (LCDD) is provided on the front side of the name-tag
type sensor node. When the front side is facing the other person,
the liquid crystal display device displays the content of display B
as a name tag with the department and name of the wearer, which
will be describe below. When the front side is facing the wearer,
the liquid crystal display device displays the organizational
activity feedback data for the wearer.
[0195] The material of the surface of the name-tag type sensor node
is transparent, so that an inserted card CRD can be seen from the
outside through the case material. The design of the name-tag
surface can be changed by replacing the card (CRD) inserted into
the name-tag type sensor node.
[0196] As described above, the name-tag type sensor node according
to the present invention can be worn by a person in the same manner
as in common name tags, allowing for obtaining physical quantities
by sensors without bringing discomfort to the wearer.
[0197] In the top and front views of FIGS. 3A and 3B, the LED lamps
LED1, LED2 are used for notifying the wearer and the person facing
the wearer, of the state of the name-tag type sensor node. The
lights of LED1 and LED2 are guided to the front side and the top
side, respectively. The lighting state can be seen both from the
wearer of the name-tag type sensor node and from the person facing
the wearer.
[0198] As described above, the name-tag type sensor node includes
the speaker SP. The speaker SP is used for notifying the wearer and
the person facing the wearer, of the state of the name-tag type
sensor node by buzzer or voice. The microphone MIC obtains the
speech of the wearer of the name-tag type sensor node as well as
the sound around the wearer.
[0199] The luminance sensors LS1F, LS1B are provided on the front
and back of the name-tag type sensor node, respectively. From the
luminance values obtained by the LS1F and LS1B, it is detected that
the name-tag type sensor node of the wearer is reversed, which is
notified to the wearer.
[0200] As is apparent from FIG. 3E, three buttons of BTN1, BTN2,
BTN3 are provided on the left side of the name-tag type sensor
node. These buttons are used for changing the operation mode of
wireless communication, and switching the liquid crystal
display.
[0201] In the bottom side of the name-tag type sensor node, there
are provided a power switch PSW, a reset button RBTN, a cradle
connector CRDIF, and an external expansion connector EXPT.
[0202] In the front side of the name-tag type sensor node, there
are provided plural infrared transceivers TRIR1 to TRIR4. The
provision of plural infrared transceivers is specific to the
name-tag type sensor node. The infrared transceiver intermittently
transmits the identification number (TRMD) of the own name-tag type
sensor node by infrared radiation. Another function of the infrared
transceiver is to receive the identification number transmitted by
the name-tag type sensor node worn by the other person. In this
way, the facing state is recorded about which name-tag type sensor
node does and when it occurs. Thus, it is possible to detect the
state of face-to-face communication between the wearers. In the
example shown in FIGS. 3A to 3E, four infrared transceivers TRIR1
to TROR4 are provided in the upper portion of the name-tag type
sensor node.
<Description of the Placement of the Infrared Transceiver
Modules>
[0203] Next, the infrared placement in the name-tag type sensor
node of this example will be described with reference to FIGS. 4A
to 4C. FIG. 4A shows the positional relationship between two
persons HUM3, HUM4 communicating face-to-face. It rarely happens
that two persons are perfectly in front of each other. They often
stand diagonally opposite to each other at about shoulder width. At
this time, the facing state between the name-tag type sensor nodes
may not be detected if the infrared transceivers have sensitivity
only in the front of the name tag. It is necessary to have
sensitivity at angles of about 30 degrees left and right relative
to lines L4, L6 drawn from the surfaces of name-tag type sensor
nodes NN2, NN3 worn by HUM3, HUM4, respectively.
[0204] FIG. 4B shows the positional relationship when the person
HUM1 sitting in a chair and the person HUM2 standing are
communicating with each other. There is a difference in height
position of the head between the person sitting in the chair and
the person standing, so that the upper body of the person HUM1
sitting in the chair is slightly tilted upward. A line L3
connecting name-tag type sensor nodes NN10 and NN11 worn by HUM1
and HUM2, is located below lines L1, L2 drawn from the respective
name-tag surfaces. Under this condition, the two name-tag type
sensor nodes should have downward sensitivity in order to reliably
detect the facing state.
[0205] FIG. 4C shows an example of the placement of the infrared
transceivers TRIR1 to TRIR4. The infrared transceivers TRIR1 and
TRIR4, which are provided outside, are placed at an angle of 15
degrees outward in the horizontal direction. The infrared
transceivers TRIR2 and TRIR3, which are provided inside, are placed
at an angle of 15 degrees outward in the horizontal direction and
at an angle of 30 degrees downward in the vertical direction. In
addition, the infrared transceiver itself has sensitivity at an
angle of about .+-.15 degrees. As a result, this placement realizes
the sensitivity of 45 degrees downward, 15 degrees upward, and
.+-.30 degrees left and right of the name tag in total. This makes
it possible to reliably obtain the state of face-to-face
communication between persons. It is needless to say that the
number and angle of the infrared transceivers TRIR1 to TRIR4 are
not limited to the placement in this example.
<Description of the Display Screen and Buttons>
[0206] As described above, the triaxial acceleration sensor (ACC)
mounted on the name-tag type sensor node can detect movements of
the wearer. At the same time, the triaxial acceleration sensor
(ACC) can detect the orientation of the name-tag type sensor node
by detecting the acceleration of gravity.
[0207] FIG. 5 shows the axes of the triaxial acceleration detected
by the name-tag type sensor node of this example. The example
defines that the acceleration applied in the horizontal direction
of the name-tag type sensor node is X axis, the acceleration
applied in the vertical direction is Y axis, and the acceleration
applied in the cross direction is Z axis.
[0208] At this time, focusing on the acceleration detected in the Y
axis. The Y axis is positive in the downward direction of the
name-tag type sensor node. When the person wears the name-tag type
sensor node and stops moving, the force of gravity acts on the
bottom side of the name tag (in the Y axis direction), and thus 1G
is detected in the Y axis. When the person takes up the name-tag
type sensor node and faces it toward that person, the bottom side
of the name tag does not face in the gravity direction. Thus, the
acceleration detected in the Y axis is a value smaller than 1G. The
value is negative when the name-tag type sensor node is completely
turned upside down.
[0209] A node up/down detection circuit UDDET monitors whether the
static acceleration applied to the Y axis is 1G or a smaller value,
in order to detect whether the name-tag type sensor node is facing
the wearer or the other person. The name-tag type sensor node
changes the content to be displayed on the liquid crystal display
device based on a detection result, namely, an up/down detection
signal UDDETS in FIG. 2A.
[0210] Here, the function of the display screen and buttons of the
name-tag type sensor node will be described.
(1) When the Name-Tag Type Sensor Node is not Upside Down (and is
Facing the Other Person)
[0211] When the name-tag type sensor node is facing the other
person, the liquid crystal display device LCDD displays the
personal data including the name and the department. At this time,
the buttons are assigned in the following way:
Button 1: not assigned Button 2: not assigned Button 3: sift to
power saving mode, release
[0212] When an association is established between the name-tag type
sensor node and the base station (when communication can be
normally performed), the wireless transmission interval is extended
to suppress the power consumption by pressing the button 3. On the
other hand, the extended wireless transmission interval is returned
to normal mode when the pressing the button 3.
(2) When the Name-Tag Type Sensor Node is Upside Down (and is
Facing the Wearer)
[0213] When the name-tag type sensor node is facing the wearer, the
wearer is operating the name-tag type sensor node. The liquid
crystal display device LCDD displays a name-tag state display
screen (Status screen), a display screen of infrared communication
history (IrAct screen), an organizational performance input screen
(Rating screen), and a name tag setting screen (Option screen). At
this time, the buttons are assigned in the following way:
Button 1: scroll, selection button Button 2: determination, switch
button Button 3: paging button
[0214] An example of the screen transition and button functions
will be described with reference to FIG. 6. Reference numeral D101
denotes an example of the display screen when the name-tag type
sensor node is not upside down (and is facing the other person). It
functions as a name tag with the department and name of the wearer
displayed thereon.
[0215] Here, when a wearer turns the display to face the wearer and
the name-tag type sensor node is upside down (D201), the display is
changed to Status screen (D110). The Status screen is a display
screen displaying the operation of the name-tag type sensor node,
such as the communication state with the base station and the
detected infrared ID. The screen is changed to the IrAct screen
(D120), Message screen (D130), Rating screen (D140), and Option
screen (D150) each time the button 3 is pressed as the paging
button. The display screen is returned to the Status screen when
the button 3 is pressed in the Option screen.
[0216] The IrAct screen (D120) is a screen displaying the number of
times the infrared radiation is received from the persons with whom
the wearer has communicated face-to-face in the day. The infrared
reception number is the information about the face-to-face
communication time. This information shows that the larger the
value, the longer the face-to-face communication time. Information
for three persons is displayed on the screen at a time. As for the
remaining persons other than the three persons, the screen is
scrolled to display the information one by one (D121, D122) each
time the button 1 is pressed. Further, the screen shifts to a mode
of hourly display when the button 2 is pressed in the IrAct screen.
In this case, the screen can also be scrolled by the button 1. When
the button 2 is pressed again in the hourly display (D125, D126),
the screen returns to the daily display (D120, D121, D122).
[0217] The Message screen is a screen for transmitting a message to
a specific name-tag type sensor node from the application or from
the other name-tag type sensor node, and transmitting a response to
the message (D130).
[0218] In the Rating screen (D140), the wearer inputs subjective
evaluations of the organizational performances at an arbitrary
time. In this example, the performances in terms of health state
(Health), mental state (Mental), and motivation to study (Study)
are rated in five grades. The input ratings are transferred to the
application server (AS), and are used for the correlation
coefficient study (BMD) of the organizational activity analysis
(BME).
<Cradle and Battery for Cradle of the Name-Tag Type Sensor
Node>
[0219] The above described name-tag type sensor node of this
example includes a secondary battery, in combination with a cradle
as a means of charging the built-in secondary battery. Of course,
an external power supply unit does not necessarily have the
configuration of a cradle, as a means of supplying power from the
outside to the name-tag type sensor node. For example, power may be
supplied directly from an AC adaptor.
[0220] FIG. 7 shows an example of the configuration between a
cradle CRD and the name-tag type sensor node NN. In this example, a
cradle connection interface CRDIF is provided in the bottom of the
name-tag type sensor node NN. The cradle connection interface CRDIF
is connected to a connection interface CCRDIF on the side of the
cradle CRD, and then power is supplied.
[0221] Here, the cradle CRD does not include a battery, so that the
power is constantly supplied from the AC adaptor and the like. The
name-tag type sensor node is used in the office environment. For
this reason, the name-tag type sensor node is assumed to be charged
at night by attaching to the cradle after office hours. However,
some workplaces have a rule that the last person turns off a
breaker to shut the power off in the room. In this case, no power
is supplied to the cradle at night, so that the name-tag type
sensor node is not charged.
[0222] In such workplaces, a secondary battery is connected to
operate the cradle during night hours. This is the battery for
cradle CRDBATT shown in FIG. 7, which is specific to this example.
FIG. 8 shows the connection relationship among the name-tag type
sensor node NN, the cradle CRD, and the battery for cradle
CRDBATT.
[0223] The name-tag type sensor node NN is charged with power from
the outside through an EPOW+terminal and an EPOW-terminal of the
interface CRDIF with the cradle CRD. The cradle CRD supplies the
power supplied from ADP+ and ADP-, to the EPOW+terminal and
EPOW-terminal of the name-tag type sensor node NN. In this way, the
built-in secondary battery of the name-tag type sensor node is
charged.
[0224] Here, assuming a case in which power is supplied by the AC
adaptor and the like through ADP+ and ADP- of the cradle. When the
last person turns off the breaker, the power to the name-tag type
sensor node is also shut off, and the built-in secondary battery of
the name-tag type sensor node is not charged. In such a case,
CRDBATT is inserted into the cradle CRD.
[0225] The battery for cradle CRDBATT is supplied with power from
the AC adaptor (ACADP) and the like through AC+ and AC- of an
external power supply terminal ACIF. Then, the battery for cradle
CRDBATT charges the built-in secondary battery. When power is
supplied from the external power supply terminal ACIF, the cradle
CRD is directly supplied with the power through the cradle
interface CRDBATTIF. In this way, the power of the built-in
secondary battery is continued to be supplied to the cradle CRD,
after the power supply from the AC adaptor ACADP is shut off. With
this configuration, the built-in secondary battery of the name-tag
type sensor node is reliably charged, thereby preventing missing
data due to battery exhaustion.
[0226] Next, specific examples of the hardware configurations of
the name-tag type sensor node, the cradle, and the battery for
cradle will be sequentially described in detail with reference to
the drawings.
<Hardware Configuration of the Name-Tag Type Sensor Node>
[0227] FIG. 9 shows a specific example of the hardware
configuration of the name-tag type sensor node NN shown in FIG. 2A.
The hardware of the name-tag type sensor node NN is roughly divided
into a power supply unit NN1P and a main body NN1M.
[0228] The power supply unit NN1P includes a built-in secondary
battery BATT, a regulator REG, a power switch PSW, and an external
power detection circuit PDET. The power supply unit NN1P stabilizes
the power from the secondary battery BATT by the regulator REG, and
supplies the power to the main body NN1M through BATPOW+, PBTPAW-.
The power supply unit NN1P includes the cradle interface CRDIF.
When the power supply unit NN1P is attached to the cradle, the
secondary battery BATT is charged. At the same time, the external
power detection circuit PDET detects that the power is supplied
from the outside, and notifies the main body by the external power
detection signal PDETS. The power of the name-tag type sensor node
can be turned on/off by the power switch PSW. Even when the power
is turned off, the secondary battery is charged by attaching the
name-tag type sensor node to the cradle.
[0229] In this example, the power is supplied from the cradle.
However, the function and configuration of the power supply NN1P is
the same when the power is supplied directly from the AC adaptor
and the like, to the name-tag type sensor node. The PDETS signal is
connected to a general purpose IO port PIO of the main body NN1M of
the name-tag type sensor node. With this configuration, the main
body of the name-tag type sensor node can recognize whether the
power is supplied from the external power supply unit.
[0230] The name-tag type sensor node is mainly controlled by a
microcomputer MCU of the main body NN1M. The microcomputer MCU is a
large scale integrated circuit LSI that integrates various
peripheral functions through an internal bus IBUS, in addition to a
central processing unit CPU. Examples of typical peripheral
functions incorporated in the microcomputer are a serial interface,
an A/D converter, a memory, a timer, and a general purpose IO port.
This example shows a microcomputer integrating three-channel serial
interfaces (SIO0, SI01, SIO2), an A/D converter (ADC), a timer
(TIMR), a general purpose IO port (PIO), a random access memory
(RAM), and a flash memory (FLSH).
[0231] The name-tag type sensor node NN converts the information
obtained from the various sensors into digital values by the A/D
converter ADC. Then, the name-tag type sensor node NN stores the
digital values into the memory unit STRG together with the
face-to-face communication information obtained by the infrared
transceivers TRIR1 to TRIR4, while transmitting the data to the
base station through a wireless communication circuit RF. Further,
the name-tag type sensor node NN analyzes the data obtained from
the sensors, and displays the results on the display device LCDD.
The display device LCDD is controlled by the general purpose IO
port PIO through LCDIF. The name-tag type sensor node NN further
includes an expansion port EXPT capable of inputting/outputting
analog and digital values for possible future expansion. The
expansion port EXPT includes analog input/output terminals EXAD0,
EXAD1, in addition to a signal EXTIO for the general purpose IO
port.
[0232] The triaxial acceleration sensor ACC, the microphone MIC for
obtaining voice, the temperature sensor THM, and the luminance
sensors LS1F, LS1B are all connected to the A/D converter ADC. In
this example, the A/D converter ADC has six input channels (AD0 to
AD5). The channels AD4 and AD5 can also be used as D/A
converters.
[0233] The A/D converter receives data from various sensors. In
addition, the A/D converter is connected to analog input/output
terminals EXTAD0, EXTAD1 of the external expansion port EXPT, and
is also connected to a terminal voltage BATDETS of the secondary
battery BATT to detect exhaustion of the secondary battery
BATT.
[0234] Generally, the number of input ports of the A/D converter is
limited while being connected to a wide variety of sensors. In this
example, the number of ports is also insufficient for the number of
sensors. In order to overcome this problem, one port is used in a
time-sharing manner to allow for A/D conversion of the desired
sensor information.
[0235] With respect to the data from the triaxial acceleration
sensor ACC, the amount of change is significant and the frequency
of acquisition is high. Thus, the data is independently assigned to
AD0 to AD2.
[0236] The voice input from the microphone MIC is amplified in an
input amplifier IAMP, and passes through a low pass filter LPF to
cut frequency elements exceeding the Nyquist frequency. Then, it is
obtained data SNDD as the real voice, as well as energy AVGD
integrated by the integrating circuit AVG. An analog switch SEL1
selects between the data SNDD and the energy AVGD, and inputs to
the channel AD3.
[0237] An analog switch SEL2 selects among the external input
signal EXTAD0 from the external expansion port EXPT, the terminal
voltage BATDETS of the secondary battery BATT, and the voice output
to the speaker. Then, the analog switch SEL2 connects the selected
signal to the channel AD4.
[0238] The voice output to the speaker is amplified by an output
amplifier OAMP to drive the speaker SP.
[0239] An analog switch SEL3 selects among data THMD obtained by
the temperature sensor THM, data LS1FD, LS1BD obtained by the
luminance sensors LS1F, LS1B, and the external input signal EXTAD1
from the external expansion port EXPT. Then, the analog switch SEL3
inputs the selected signal to the channel AD5.
[0240] The analog switches SEL1, SEL2, SEL3 provided in the A/D
converter are controlled by an ADSEL signal output from the general
purpose IO port PIO.
[0241] The wireless communication circuit RF communicates with the
microcomputer MCU through RFIF which is a serial communication.
Because the amount of communication data is large and the usage
frequency is high, a serial interface channel 0 (SIO0) is
exclusively assigned to the wireless communication circuit RF.
Further, the infrared transceivers should be kept ready to perform
a waiting operation, in order to receive the ID from the other
name-tag sensor node and obtain face-to-face communication
information. Thus, the infrared transceivers are connected to a
serial port channel 1 (SIO1). In this example, the transmission
circuits of the four infrared transceivers TRIR1 to TRIR4 are
driven by a channel 1 serial transmission signal SIO1TxD which is
common to all the transmission circuits. With respect to the
reception, the receivers of the four infrared transceivers TRIR1 to
TRIR4 are ORed (IROR1), and connected to a channel 1 serial
reception signal SIO1RxD.
[0242] A signal STRGIF is for the memory unit STRG. A signal RTCIF
is for a real time clock RTC to obtain absolute time. A
communication means EXTSIO communicates with the cradle. These
signals also use a serial communication interface, but the usage
frequency is limited. Thus, a serial port channel 2 (SIO2) is used
in a time-sharing manner. At this time, a selector SSEL2 switches
the signals by a signal SIO2SEL output from the general purpose IO
port PIO.
[0243] The operation timing of the CPU of the name-tag type sensor
node is determined by the following factors: the time information
from the real time clock RTC; when the voice obtained by the
microphone MIC exceeds certain energy; and when input from the
buttons (BTN1, BTN2, BTN3) is received. These factors can generate
interrupt signals RTCINT, SNDINT, BTNINT to the CPU, respectively.
A comparator CMP1 detects that energy AVGD of the voice exceeds a
predetermined value, and generates the interrupt signal SNDINT to
the CPU. The button inputs from BTN1, BTN2, BTN3 can be obtained by
the general purpose IO port (PIO) through BTN11F, BTN21F, BTN31F,
respectively. Further, an OR circuit (OR2) detects the input change
and generates the button interrupt signal BTNINT.
[0244] When a reset button RBTN is pressed, the CPU can be reset
through a reset interface RSTS.
<Hardware Configuration of the Name-Tag Type Sensor Node
Cradle>
[0245] A specific example of the hardware configuration of the
name-tag type sensor node cradle CRD will be described with
reference to FIG. 10. The name-tag type sensor node cradle of this
example is roughly divided into a power supply unit CRD1P and a
main body CRD1M.
[0246] The power supply unit CRD1P includes a charging circuit CHG
for charging the built-in secondary battery of the name-tag type
sensor node through the cradle interface CCRDIF from an external
power supply, and a regulator CREG for stabilizing the power for
the operation of the cradle itself. The cradle is supplied with
power through terminals ADP+, ADP- of a cradle battery interface
CBATIF, by means of an external power supply such as the AC
adaptor, or the battery for cradle described below.
[0247] The power supplied through ADP+, ADP- is stabilized by the
regulator CREG, and is supplied to the cradle main body CRD1M
through CPOW+, CPOW-. At the same time, the power is used for
charging the secondary battery of the name-tag type sensor node
through EPOW+, EPOW- of an interface CRDCRDIF between the cradle
and the name-tag type sensor node, from the charging circuit
CHG.
[0248] The main body CRD1M of the name-tag type sensor node cradle
has a sensor node circuitry including: a wireless communication
circuit CRF for performing wireless communication; a microcomputer
CMCU for controlling the wireless communication circuit CRF;
infrared transceivers CTRIR1 and CTRIR2; a real time clock CRTC;
and a memory unit CSTRG. The wireless communication circuit CRF,
the microcomputer CMCU for controlling the wireless communication
circuit CRF, and the infrared transceivers CTRIR1 and CTRIR2
correspond to the wireless communication circuit RF, the
microcomputer MCU for controlling the wireless communication
circuit RF, and the infrared transceivers TRIRI1 to TRIR4 in the
name-tag type sensor node, respectively. These components can
communicate with the base station (GW) of the name-tag sensor node.
The cradle serves to supply power to an object attached thereto,
and generally has only the power supply unit. The sensor node
circuitry incorporated in the main body CRD1M is specific to this
example.
[0249] The cradle is mainly controlled by the microcomputer CMCU of
the main body. The microcomputer CMCU is an LSI that integrates
various peripheral functions through an internal bus CIBUS, in
addition to a central processing unit CCPU. In this example, the
microcomputer integrates three-channel serial interfaces (CSIO0,
CSIO1, CSIO2), a timer (CTIMR), a general purpose IO port (CPIO), a
random access memory (CRAM), and a flash memory (CFLSH).
[0250] The wireless communication circuit CRF communicates with the
microcomputer CMCU through CRFIF which is a serial communication.
Because the amount of communication data is large and the usage
frequency is high, a serial interface channel 0 (CSIO0) is
exclusively assigned to the wireless communication circuit CRF.
Further, the infrared transceivers CTRIR1 and CTRIR2 should be kept
ready to perform a waiting operation, in order to receive the ID
from the other name-tag sensor node and obtain face-to-face
communication information. Thus, the infrared transceivers are
connected to a serial port channel 1 (CSIO1). In this example,
transmission circuits of the two infrared transceivers CTRIR1 and
CTRIR2 are driven by a channel 1 serial transmission signal
CSIO1TxD which is common to all the transmission circuits. With
respect to the reception, the receivers of the two infrared
transceivers CTRIR1 and CTRIR2 are ORed (CIROR), and connected to a
channel 1 serial reception signal CSIO1RxD.
[0251] A signal CSTRGIF is for the memory unit CSTRG. A signal
CRTCIF is for the real time clock CRTC to obtain absolute time. A
communication means CEXTSIO communicates with the cradle. These
signals also use a serial communication interface, but the usage
frequency is limited. Thus, a serial port channel 2 (CSIO2) is used
in a time-sharing manner. At this time, a selector CSSEL2 switches
the signals by a signal CSIO2SEL output from the general purpose IO
port PIO.
[0252] That is, the cradle of this example has a function of
detecting that the cradle is facing the name-tag type sensor node,
and wirelessly transmitting the information. The cradle is assumed
to be placed on a desk. When a person wearing the name-tag type
sensor node sits in front of the desk, an infrared communication is
performed between the name-tag type sensor node and the cradle. In
this way, information is recorded about who is sitting in that
place and when he/she is.
<Hardware Configuration of the Battery for Cradle>
[0253] A specific example of the hardware configuration of the
battery for cradle will be described with reference to FIG. 11. The
hardware of the battery for cradle includes a secondary battery
BATTS2, and a circuit BCHG for charging the secondary battery
BATTS2. The cradle is supplied with power through BBATIF having two
terminals ADP+, ADP-. When the AC adopter is connected to the
battery for cradle through diodes D1, D2, power is directly
supplied to the cradle by the AC adaptor through the terminals AC+,
AC-. On the other hand when the AC adaptor is not connected to the
battery for cradle, power is supplied to the cradle from the
secondary battery BATTS2.
[0254] In this example, the secondary battery BATTS2 includes
batteries connected in two-parallel and two-series arrays. Each
battery is the same as the secondary battery incorporated in the
name-tag type sensor node. Logically, the secondary battery
incorporated in the name-tag type sensor node would be charged with
the power of one battery. However, the secondary battery is
generally charged with a high voltage. For this reason, it is
designed to use a series connection to gain voltage, as well as a
two-parallel connection to store a sufficient amount of power.
<Communication Operation of the Name-Tag Type Sensor
Node>
[0255] Next, an example of the communication operation of the
name-tag type sensor node will be described. The name-tag type
sensor node obtains physical quantities necessary to calculate
organizational activities. The name-tag type sensor node displays
the output on the name tag while transmitting to the base station.
The name-tag type sensor node is used by a person wearing it, and
preferably small and lightweight. Thus, it is necessary to have a
small battery for operating the name-tag type sensor node. In order
to continuously obtain physical quantities from the sensors while
reducing power consumption, the acquisition of the physical
quantities from the sensors and the transmission operation of the
sensor data from the sensors, are intermittently performed.
[0256] This sequence will be described with reference to FIGS. 12A
to 12F. FIGS. 12A to 12F show an example of the timing of obtaining
sensor data as physical quantity data from the sensors, the timing
of transmitting the sensor data, and the timing of writing the
sensor data into the memory unit. FIG. 12A shows the timing of
obtaining voice from the microphone by the A/D converter.
Generally, in order to obtain a voice waveform, it is necessary to
perform sampling at a frequency of several kHz to several tens of
kHz. This example shows the timing of sampling at an even interval
of time TSN1. Similarly, FIG. 12B shows the timing of obtaining
acceleration by the A/D converter at a constant interval of TNS2.
FIG. 12C shows the timing of obtaining temperature and luminance by
the A/D converter. The acceleration is obtained at an interval of
time TSN2. The temperature and luminance are obtained at an
interval of time TSN3. Generally, voice is the largest in terms of
physical quantity per unit of time, followed by acceleration,
temperature, and luminance.
[0257] Generally, the timing of sampling of the physical quantities
is arbitrary depending on the sensor type, and the magnitude of the
timing interval is not limited. Here shows an example of obtaining
data from the sensors at constant intervals of
TSN1<TSN2<TSN3.
[0258] The physical quantities obtained by the sensors are
wirelessly transmitted as a packet of an arbitrary size. FIG. 12D
shows the timing of wirelessly transmitting the packet. A data set
SENSD1, which contains 4 data pieces of voice, 2 data pieces of
acceleration, and 1 data piece of temperature and of luminance, is
wirelessly transmitted as a packet TRD1. Similarly, data sets
SENSD2, SENSD3 are wirelessly transmitted as packets TRD2, TRD3,
respectively. The wireless transmission interval is not necessarily
constant. Here shows an example of the timing of wireless
transmission at a constant interval of time TTR1.
[0259] FIG. 12E shows the timing of storing the physical quantity
data obtained by the sensors into the memory unit. In this example,
there is shown the timing of storing the data set SENSD1 containing
4 data pieces of voice, 2 data pieces of acceleration, and 1 data
piece of temperature and of luminance, into the memory unit as data
CMBD1. Similarly, the data sets SENSD2, SENSD3 are stored in the
memory unit as data CMBD2 and CMBD3, respectively. The frequency
and interval of the writing timing to the memory unit are not
limited in the present invention.
[0260] FIG. 12F shows the state of the external power detection
signal PDETS for detecting the connection of the name-tag type
sensor node to the external power supply. When PDETS indicates a
high level, the name-tag type sensor node is attached, for example,
to the cradle and supplied with power from the outside to charge
the secondary battery.
[0261] Generally when a terminal and a receiver are distant from
each other or affected by outside noise or other problems, the
wireless communication may not be normally performed. This is the
same in the case of communication between the name-tag type sensor
node and the base station. There might be a possibility that the
communication is not normally completed, for example, when there is
no base station near the name-tag type sensor node. In the example
shown in FIGS. 12A to 12F, the packets TRD2, TRD4, TRD5 are not
normally transmitted. Even if the transfer to the base station is
failed, the data is not missing because the data CMBD2, CMBD4,
CMBD5 corresponding to TRD2, TRD4, TRD5 obtained from the sensors,
are still stored in the memory unit. The data is retransferred to
the base station after communication is recovered. Finally, it is
possible to prevent missing data to be collected. The
retransmission of the data stored in the memory unit to prevent
missing data, is called bulk transmission.
[0262] The bulk transmission is performed when the name-tag type
sensor node is connected to the external power supply. This
sequence is specific to this example.
[0263] FIG. 12F shows that the PDETS signal is changed to a high
level at a timing T1 and the external power supply is connected to
the name-tag type sensor node. The name-tag type sensor node starts
the bulk transmission upon detection of the PDETS signal.
[0264] In the case of the wireless transmission timing shown in
FIG. 12D, when the PEDTS signal is changed to the high level at the
timing T1, a packet TRD2R generated from the data CMBD2 stored in
the memory unit is transferred after transfer of the packet TRD6.
The packet TRD2R corresponds to the packet TRD2 that has failed to
be transferred. Similarly, TRD4R as retransmission data of the
packet TRD4, and TRD5R as retransmission data of the packet TRD5
are transferred after transfer of the packets TRD7, TRD8,
respectively.
[0265] The amount of transferred data increases during the bulk
transmission. Thus, the transfer interval TTR1 is changed to TTR2
which is shorter than TTR1. This is done, as described above in
FIG. 2A, by switching the time bases TB1, TB2 by TMGSEL in the
transfer timing controller TRTMG, and by switching the data to be
communicated by appropriately controlling the communication data
selector TRDSEL.
[0266] In this example, the data is continuously obtained from the
sensors after the external power supply is connected. However, for
example, when the name-tag type sensor node is not worn by a person
and data is not necessary, the data acquisition from the sensors
may be interrupted for bulk transmission. Also in this case, the
bulk transmission can be effectively performed by reducing the
transfer interval.
<Description of the Operation of the Name-Tag Type Sensor
Node>
[0267] The operation software of the name-tag type sensor node is
called firmware. The firmware is stored in the flash memory FLSH
incorporated in the microcomputer MCU shown in FIG. 9. Sometimes it
is necessary to change the operation software of the name-tag type
sensor node due to failure of the software or change of the
operation algorithm. Generally, the flash memory is rewritten by
dedicated hardware provided by the manufacture of the
microcomputer. However, such hardware does not support simultaneous
rewriting of plural flash memories. The name-tag type sensor node
is worn by an individual to recognize the activities of the
organization. Thus, the number of name-tag type sensor nodes is
equal to the number of wearers. It takes a lot of time and
unrealistic to collect all the name-tag type sensor nodes for each
firmware update and to rewrite the flash memories one by one.
[0268] In this example, the name-tag type sensor node NN has a
function of wirelessly transferring the firmware to be updated and
updating such firmware. This sequence will be described with
reference to the drawings.
[0269] In the business microscope system shown in FIGS. 2A, 2B, the
name-tag type sensor node firmware SSTF to be updated is registered
in the memory unit SSME of the sensor network server SS. Although
the registration means TFI is not so limited, for example, the
firmware may be transferred by FTP through a network NW.
[0270] The operation of the name-tag type sensor node including
update of the firmware will be described with reference to FIGS.
13A to 13D and FIG. 14. FIGS. 13A to 13D show the flow of data and
the timing. It is shown that the data is obtained by the sensors,
transferred from the name-tag type sensor node to the base station,
and transferred to the sensor network server SS. FIG. 14 is a
process flowchart of the name-tag type sensor node.
[0271] When the power is on and the operation is started, the
name-tag type sensor node searches the base station and performs
connection operation called associate (P117). Then, the name-tag
type sensor node performs time adjustment process to synchronize
the sensing time with the other name-tag type sensor node (P118).
Next, as described above, the name-tag type sensor node obtains
sensor information in an intermittent manner (P102), transmits the
sensor data (P103), and stores the sensor data into the memory unit
(P104). The process is performed for each interval of TTR3 (P101),
unless the name-tag type sensor node is attached to the cradle
(P105). FIGS. 13A to 13D show an example of the flow of sensor data
SND10, SND11, SND12, SND13, SND14, and SND15 that is transmitted
from the sensor node of FIG. 13C to the base station of FIG. 13B at
an interval of TTR3. The base station normally receives the sensor
data, and transfers the sensor data as SND21, SND22, SND24, and
SND25 to the sensor network server (SS) of FIG. 13A. At this time,
sensor data SND10, SND13, SND14 indicated by the dotted lines is
not normally transferred to the base station due to disturbance or
other problems, and thus not transferred to the sensor network
server. This is repeated during the intermittent sensing operation
(TP).
[0272] FIG. 13D shows an example of the case in which the name-tag
type sensor node is connected to the external power supply by
attaching the name-tag type sensor node to the cradle, or other
means. At this time, when the external power detection signal PDETS
is changed to a high level, the name-tag type sensor node moves to
the bulk transmission operation (TC). In the bulk transmission TC,
the name-tag type sensor node reads sensor data not normally
transmitted, of the sensor data stored in the memory unit (P107),
and transmits to the base station (P108). This is repeated until
all the data is transmitted (P109) at an interval of TTR4
(106).
[0273] At this time, it is defined as TTR4<TTR3, which is a
feature of the present invention. Because the name-tag type sensor
node is attached to the cradle, the power supply is stable and the
radio wave environment is good. With these conditions, it is
possible to effectively transfer a large amount of data represented
by bulk transmission data, without exhausting the battery.
[0274] When there is no untransmitted data, the name-tag type
sensor node moves to an operation of transferring update firmware
(TF). Here, the name-tag type sensor node first inquires the sensor
network server whether update firmware is registered in the server,
through the base station (P110). More specifically, the name-tag
type sensor node transmits a query packet (FDRQ1) to the base
station. Then, the base station further transmits a query packet
(FDRQ2) to the sensor network server. When there is no update
firmware (P111), the operation is arbitrary until the name-tag type
sensor node is removed from the cradle. The normal intermittent
sensing operation may be performed, or the operation may be
stopped. The flow of FIG. 14 shows an example of stopping the
operation (P116).
[0275] When update firmware is present, the update firmware is
transferred to the name-tag type sensor node from the sensor
network server through the base station (P113). In the example of
FIGS. 13A to 13D, a packet FD2 is transferred from the sensor
network server to the base station, and a packet FD2 is transferred
from the base station to the name-tag type sensor node. This is
repeated at an interval of TTR5 (P112) until all the update
firmware is transferred (P114).
[0276] At this time, it is defined as TTR5<TTR3, which is a
feature of the present invention. Because the name-tag type sensor
node is attached to the cradle, the power supply is stable and the
radio wave environment is good. With these conditions, it is
possible to effectively transfer the data desired to be reliable,
which is represented by update firmware, without exhausting the
battery.
[0277] When all the update firmware is transferred, an operation of
rewriting firmware (TFC) is actually performed (P115). The
operation is arbitrary until the name-tag type sensor node is
removed from the cradle after completion of the rewriting. FIG. 14
shows an example of stopping the operation (P116). When the
name-tag type sensor node is removed from the cradle, it returns to
the normal intermittent sensing operation (TP).
<Low Power Operation of the Infrared Transceivers>
[0278] As described above, the name-tag type sensor nodes are
synchronously operated. A method of reducing the power consumption
will be described with reference to FIGS. 15A to 15K. FIGS. 15A to
15K show the relationship among the sensor information acquisition
timing, the wireless transmission/reception timing, and the
infrared transmission/reception timing, when a name-tag type sensor
node 1 and a name-tag type sensor node 2 face each other.
[0279] FIG. 15A shows the timing of obtaining acceleration and
voice. FIG. 15B shows the timing of wirelessly
transmitting/receiving the obtained sensor information.
[0280] FIG. 15C shows the timing that an infrared transceiver 1 of
the name-tag type sensor node 1 transmits its own ID. Similarly,
FIGS. 15D, 15E, 15F show the timing of transmissions from infrared
transceivers 2, 3, 4 of the name-tag type sensor node 1.
[0281] Since the name-tag type sensor nodes are synchronously
operated, their timings of transmitting infrared radiation are
known to each other.
[0282] In other words, the receiver waits for at least one
transmission timing interval. More specifically, as shown in FIG.
15G, the receiver of the infrared transceiver 1 of the name-tag
type sensor node 2 performs a waiting operation (IRRT1) during a
period when the infrared transceivers 1 to 4 of the name-tag type
sensor node 1 transmit at least once, namely during RTT1, IRTT2,
IRTT3, and IRTT4. This is the same for the infrared transceivers 2,
3, 4 of the name-tag type sensor node 2. As shown in FIGS. 15H,
15I, 15J, the receivers can perform the waiting operation in a
time-sharing manner (IRRT2, IRRT3, IRRT4).
[0283] Generally, the waiting state of the infrared receiver
increases the power consumption. Thus, as described above, the
intermittent operation is performed to reduce the power consumption
of the infrared receiver to one fourth or less.
[0284] Further, since the name-tag type sensor nodes are
synchronized with each other, there is no need to constantly
perform the infrared transmission and reception. In the example
shown in FIG. 15K, the infrared transmission and reception are
performed at an interval IRNIT1. During a period when the infrared
transmission and reception are not performed, MPU of the name-tag
type sensor nodes 1 and 2 is switched from a normal operation mode
(MPUMD1) to a low power consumption state (MPUMD2) in order to
reduce the power consumption.
[0285] The cradle is placed on the desk and the name-tag type
sensor node is attached to the cradle after office hours. Thus,
during the period when the name-tag type sensor node is attached to
the cradle, the power supply is stable, thereby ensuring stable
communication.
[0286] As described above, according to the configuration and
operation, when the name-tag type sensor node attached to the
cradle, a large amount of data, such as bulk transmission data, is
transferred at an increased communication frequency. Alternately,
the data desired to be reliable, such as rewriting data of the
firmware of the name-tag type sensor node, is transferred. This
allows for the data transfer without exhausting the battery of the
name-tag type sensor node and without unnecessarily compressing the
communication bandwidth.
* * * * *