Patent Publication Number: US-2023133242-A1

Title: Work assignment status monitoring system, work assignment status monitoring method, and work assignment status monitoring program

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2021-176252, filed on Oct. 28, 2021, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     The present disclosure relates to a work assignment status monitoring system, a work assignment status monitoring method, and a work assignment status monitoring program. 
     In recent years, it has been required to efficiently monitor a work assignment status(es) of one or more designated work assignments performed by a worker. 
     A production management apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2007-323199 includes a worker detection apparatus, a worker identification unit, a movement pattern identification unit, and an abnormal movement detection unit. The worker identification unit identifies, from detection information received from the worker detection apparatus, a start time for detecting a presence of a worker and an end time thereof in a process which corresponds to the detection information. A movement pattern identification unit identifies a stay time indicating a period of time for which the worker has engaged in the process and generates a movement pattern including the period of stayed time. The abnormal movement detection unit uses, as one of conditions for determining whether or not an abnormal movement pattern has occurred, a result of a comparison between a period of stayed time included in information about the movement pattern and a period of stayed time included in information about a standard movement pattern. 
     SUMMARY 
     The present disclosure is not limited to the method disclosed in Japanese Unexamined Patent Application Publication No. 2007-323199, and there is a need to continuously and efficiently monitor a work assignment status(es) of one or more designated work assignments performed by a target to be monitored such as a worker or the like. The target to be monitored will be hereinafter referred to as a monitoring target. 
     An object of the present disclosure is to provide a work assignment status monitoring system, a work assignment status monitoring method, and a work assignment status monitoring program capable of inferring a work assignment status(es) of one or more designated work assignments being performed by a monitoring target such as a worker or the like with a small amount of information and efficiently monitoring the work assignment status. 
     In an example aspect of the present disclosure, a work assignment status monitoring system includes: an acquisition unit configured to acquire information about one or more work areas; a monitoring target detection unit configured to detect either a worker or a predetermined mobile body as a monitoring target and define a first monitoring target area where the monitoring target is positioned; a first determination unit configured to determine whether or not the monitoring target has performed a work in the one or more work areas based on a presence or absence of interference with the one or more work areas by the first monitoring target area; an information generation unit configured to generate information about the work in the one or more work areas performed by the monitoring target based on a result of the determination made by the first determination unit; and an output unit configured to output information about the work assignment performed by the monitoring target generated by the information generation unit. This work assignment status monitoring system determines whether the monitoring target has performed the work assignment(s) in one or more work areas based on the presence or absence of interference with the one or more work areas by the first monitoring target area where the monitoring target such as the worker is positioned. It is thus possible to infer and monitor the work assignment status of the monitoring target with a smaller amount of information than that in the case where, for example, the movement of the monitoring target is analyzed in detail. That is, this work assignment status monitoring system can efficiently monitor the work assignment status(es) of one or more designated work assignments performed by the monitoring target such as the worker. 
     The first determination unit may be configured to determine that the monitoring target has performed the work in the work area when a period of time of the interference with the work area by the first monitoring target area in each of the work areas is more than or equal to a reference time set in the work area. 
     The information about the work assignment performed by the monitoring target in the one or more work areas may include information about a start time, a work time, and an end time of the work assignment performed by the monitoring target in each of the work areas. 
     The one or more work areas may include an area where another mobile body other than the predetermined mobile body, which is the monitoring target, is positioned. 
     The monitoring target detection unit may be configured to further detect a predetermined part of the monitoring target and define a second monitoring target area where the predetermined part is positioned. 
     The monitoring target detection unit may be configured to detect the monitoring target using either a distance measurement sensor or a camera. 
     The work assignment status monitoring system may further include: a recording unit configured to record, as a plurality of work assignment histories, a plurality of pieces of information generated by the information generation unit and related to the work assignment performed by the monitoring target; and a normal state decision unit configured to decide a normal state for the work assignment performed by the monitoring target from the plurality of work assignment histories recorded in the recording unit. The output unit may be further configured to output new information about the work assignment performed by the monitoring target generated by the information generation unit, together with a result of a comparison between the new information about the work assignment performed by the monitoring target generated by the information generation unit and information about the work assignment in the normal state. Thus, the work assignment status monitoring system can set the normal state of the work assignment order, the work time, and the like for each of the monitoring targets. It is thus possible to present whether or not the normal state for the worker who is the monitoring target is the normal state for the worker who is the monitoring target, for example, even when the work time of a certain work assignment performed by the worker who is the monitoring target is longer than those of other workers due to differences in experience and skill. 
     The output unit may be configured to output the new information about the work assignment performed by the monitoring target in a highlighted manner in accordance with a degree of deviation from the information about the work assignment in the normal state. 
     The work assignment status monitoring system may further include a second determination unit configured to determine whether or not the new information about the work assignment performed by the monitoring target is included in a range of the normal state based on the degree of deviation of the new information about the work assignment performed by the monitoring target from the information about the work assignment performed in the normal state. The output unit may be configured to further output a result of the determination made by the second determination unit. 
     The work assignment status monitoring system may further include: a recording unit configured to record, as a plurality of work assignment histories, a plurality of pieces of information generated by the information generation unit and related to the work assignment performed by the monitoring target; a normal state decision unit configured to decide a normal state for the work assignment performed by the monitoring target from the plurality of work assignment histories recorded in the recording unit; and a prediction unit configured to predict information about a work exceeding the range of the normal state among the plurality of pieces of the information about the work assignments performed by the monitoring target generated next by the information generation unit based on the degree of deviation of the plurality of pieces of information about the work assignments performed by the monitoring target recorded as the plurality of work assignment histories in the recording unit from information about the work assignment in the normal state. The output unit may be further configured to output a result of the prediction made by the prediction unit. In this manner, since the work assignment status monitoring system can predict the work that may exceed the range of the normal state for each monitoring target, for example, a warning can be given in advance to the worker who is the monitoring target. 
     In another example aspect of the present disclosure, a work assignment status monitoring method includes: an acquisition step of acquiring information about one or more work areas; a monitoring target detection step of detecting either a worker or a predetermined mobile body as a monitoring target and define a first monitoring target area where the monitoring target is positioned; a determination step of determining whether or not the monitoring target has performed a work in the one or more work areas based on a presence or absence of interference with the one or more work areas by the first monitoring target area; an information generation step of generating information about the work in the one or more work areas performed by the monitoring target based on a result of the determination made in the determination step; and a first output step of outputting information about the work assignment performed by the monitoring target generated in the information generation step. This work assignment status monitoring system determines whether the monitoring target has performed the work assignment(s) in one or more work areas based on the presence or absence of interference with the one or more work areas by the first monitoring target area where the monitoring target such as the worker is positioned. It is thus possible to infer and monitor the work assignment status of the monitoring target with a smaller amount of information than that in the case where, for example, the movement of the monitoring target is analyzed in detail. This work assignment status monitoring method determines whether the monitoring target has performed the work assignment(s) in one or more work areas based on the presence or absence of interference with the one or more work areas by the first monitoring target area where the monitoring target such as the worker is positioned. It is thus possible to infer and monitor the work assignment status of the monitoring target with a smaller amount of information than that in the case where, for example, the movement of the monitoring target is analyzed in detail. That is, this work assignment status monitoring method can efficiently monitor the work assignment status(es) of one or more designated work assignments performed by the monitoring target such as the worker. 
     The work assignment status monitoring method may further include: a recording step of recording, as a plurality of work assignment histories, a plurality of pieces of information generated in the information generation step and related to the work assignment performed by the monitoring target; a normal state decision step of deciding a normal state for the work assignment performed by the monitoring target from the plurality of work assignment histories recorded in the recording step; and a second output step of outputting new information about the work assignment performed by the monitoring target generated in the information generation step, together with a result of a comparison between the new information about the work assignment performed by the monitoring target generated in the information generation step and the information about the work assignment in the normal state. Thus, the work assignment status monitoring method can set the normal state of the work assignment order, the work time, and the like for each of the monitoring targets. It is thus possible to present whether or not the normal state for the worker who is the monitoring target is the normal state for the worker who is the monitoring target, for example, even when the work time of a certain work assignment performed by the worker who is the monitoring target is longer than those of other workers due to differences in experience and skill. 
     The work assignment status monitoring method may further include: a recording step of recording, as a plurality of work assignment histories, a plurality of pieces of information generated in the information generation step and related to the work assignment performed by the monitoring target; a normal state decision step of deciding a normal state for the work assignment performed by the monitoring target from the plurality of recorded work assignment histories recorded in the recording step; a prediction step of predicting information about a work exceeding the range of the normal state among the plurality of pieces of the information about the work assignments performed by the monitoring target generated next in the information generation step based on the degree of deviation of the plurality of pieces of information about the work assignments performed by the monitoring target recorded as the plurality of recorded work assignment histories from information about the work assignment in the normal state; and a second output step of outputting a result of the prediction. In this manner, since the work assignment status monitoring method can predict the work that may exceed the range of the normal state for each monitoring target, for example, a warning can be given in advance to the worker who is the monitoring target. 
     In another example aspect of the present disclosure, a work assignment status monitoring program includes: acquisition processing of acquiring information about one or more work areas; monitoring target detection processing of detecting either a worker or a predetermined mobile body as a monitoring target and define a first monitoring target area where the monitoring target is positioned; determination processing of determining whether or not the monitoring target has performed a work in the one or more work areas based on a presence or absence of interference with the one or more work areas by the first monitoring target area; information generation processing of generating information about the work in the one or more work areas performed by the monitoring target based on a result of the determination made in the determination processing; and first output processing of outputting information about the work assignment performed by the monitoring target generated in the information generation processing. This work assignment status monitoring program determines whether the monitoring target has performed the work assignment(s) in one or more work areas based on the presence or absence of interference with the one or more work areas by the first monitoring target area where the monitoring target such as the worker is positioned. It is thus possible to infer and monitor the work assignment status of the monitoring target with a smaller amount of information than that in the case where, for example, the movement of the monitoring target is analyzed in detail. That is, this work assignment status monitoring program can efficiently monitor the work assignment status(es) of one or more designated work assignments performed by the monitoring target such as the worker. 
     The work assignment status monitoring program may further cause a computer to execute: a recording processing of recording, as a plurality of work assignment histories, a plurality of pieces of information generated in the information generation processing and related to the work assignment performed by the monitoring target; normal state decision processing of deciding a normal state for the work assignment performed by the monitoring target from the plurality of work assignment histories recorded in the recording processing; and a second output processing of outputting new information about the work assignment performed by the monitoring target generated in the information generation processing, together with a result of a comparison between the new information about the work assignment performed by the monitoring target generated in the information generation processing and the information about the work assignment in the normal state. Thus, the work assignment status monitoring program can set the normal state of the work assignment order, the work time, and the like for each of the monitoring targets. It is thus possible to present whether or not the normal state for the worker who is the monitoring target is the normal state for the worker who is the monitoring target, for example, even when the work time of a certain work assignment performed by the worker who is the monitoring target is longer than those of other workers due to differences in experience and skill. 
     The work assignment status monitoring program may further cause the computer to execute: a recording processing of recording, as a plurality of work assignment histories, a plurality of pieces of information generated in the information generation processing and related to the work assignment performed by the monitoring target; normal state decision processing of deciding a normal state for the work assignment performed by the monitoring target from the plurality of recorded work assignment histories recorded in the recording processing; prediction processing of predicting information about a work exceeding the range of the normal state among the plurality of pieces of the information about the work assignments performed by the monitoring target generated next in the information generation processing based on the degree of deviation of the plurality of pieces of information about the work assignments performed by the monitoring target recorded as the plurality of recorded work assignment histories from information about the work assignment in the normal state; and second output processing of outputting a result of the prediction. In this manner, since the work assignment status monitoring program can predict the work that may exceed the range of the normal state for each monitoring target, for example, a warning can be given in advance to the worker who is the monitoring target. 
     According to the present disclosure, it is possible to provide a work assignment status monitoring system, a work assignment status monitoring method, and a work assignment status monitoring program capable of inferring a work assignment status(es) of one or more designated work assignments being performed by a monitoring target such as a worker or the like with a small amount of information and efficiently monitoring the work assignment status. 
     The above and other objects, features and advantages of the present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a block diagram showing a configuration example of a work assignment status monitoring system according to a first embodiment; 
         FIG.  2    is a schematic perspective view showing an application example of the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  3    is a schematic plan view showing an application example of the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  4    is a flowchart showing an operation of the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  5    is a schematic plan view showing in more detail a facility to which the work assignment status monitoring system shown in  FIG.  1    is applied; 
         FIG.  6    shows a first example of information about work assignments performed by a monitoring target output from a work assignment status monitoring apparatus provided in the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  7    shows a second example of information about work assignments performed by the monitoring target output from the work assignment status monitoring apparatus provided in the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  8    shows a third example of information about work assignments performed by the monitoring target output from the work assignment status monitoring apparatus provided in the work assignment status monitoring system shown in  FIG.  1   ; 
         FIG.  9    is a block diagram showing a configuration example of a work assignment status monitoring system according to a second embodiment; 
         FIG.  10    is a flowchart showing a determination operation performed by the work assignment status monitoring apparatus provided in the work assignment status monitoring system shown in  FIG.  9   ; 
         FIG.  11    is a flowchart showing a prediction operation performed by the work assignment status monitoring apparatus provided in the work assignment status monitoring system shown in  FIG.  9   ; 
         FIG.  12    shows an example of an event network classified from a plurality of work assignment histories and a work assignment procedure of a plurality of events on the event network in a matrix; 
         FIG.  13    shows an example of an event network classified from a plurality of work assignment histories and a work assignment procedure of a plurality of events on the event network in a matrix; 
         FIG.  14    shows an example of an event network classified from a plurality of work assignment histories and a work assignment procedure of a plurality of events on the event network in a matrix; and 
         FIG.  15    shows a probability distribution defined on the DSM. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, the present disclosure will be described through embodiments of the disclosure, but the disclosure according to the claims is not limited to the following embodiments. Further, not all of the configurations described in the embodiments are necessary for solving the problem. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each of the drawings, the same elements are denoted by the same reference signs, and repeated explanations are omitted if necessary. 
     First Embodiment 
       FIG.  1    is a block diagram showing a configuration example of a work assignment status monitoring system  1  according to a first embodiment.  FIGS.  2  and  3    are a schematic perspective view and a schematic plan view, respectively, showing an application example of the work assignment status monitoring system  1  shown in  FIG.  1   . The work assignment status monitoring system  1  according to this embodiment is applied, for example, to a facility such as a factory having one or more work areas where predetermined work assignments are performed by workers or the like who are monitoring targets, and determines whether each of the monitoring targets has performed the work assignment(s) in one or more work areas based on the presence or absence of interference (contact) with the one or more work areas by an area to be monitored where the monitoring target is positioned. In this way, the work assignment status monitoring system  1  according to this embodiment can infer and monitor the work assignment status of the monitoring target with a smaller amount of information than that in the case where, for example, the movement of the monitoring target is analyzed in detail. That is, the work assignment status monitoring system  1  according to this embodiment can efficiently monitor the work assignment status(es) of one or more designated work assignments performed by a monitoring target such as a worker. A specific description of the work status monitoring system  1  according to this embodiment will be given below. 
     The work assignment status monitoring system  1  is applied to a facility PL 1  such as a factory, and includes n (n is an integer of one or more) sensors  11 _ 1  to  11 _ n  and a work assignment status monitoring apparatus  12 . The work assignment status monitoring system  1  may be a single work assignment status monitoring apparatus  12 . 
     The sensors  11 _ 1  to  11 _ n  are installed on the ceiling or the like of the facility PL 1 , and detects a worker  901  and a mobile body  902  in the facility PL 1 . The mobile body  902  is, for example, a vehicle such as a forklift or a movable carriage for transporting a product or its parts, a vehicle such as an AGV (Automatic Guided Vehicle) configured to automatically perform a transportation work, or an autonomously movable work robot configured to automatically perform a predetermined work assignment. Some of the sensors  11 _ 1  to  11 _ n  may be attached to any of the mobile bodies  902 . Each of the sensors  11 _ 1  to  11 _ n  can simultaneously detect all the workers  901  and the mobile bodies  902  included in a detection range by itself. 
     Each of the sensors  11 _ 1  to  11 _ n  is, for example, a camera, and is installed so as to be capable of capturing the entire facility including one or more work areas provided in the facility PL 1  and moving routes of the worker  901  and the mobile body  902 . Each of the sensors  11 _ 1  to  11 _ n  is not limited to a camera, and may instead be any type of sensor such as a distance measuring sensor capable of detecting the worker  901  and the mobile body  902 . In this embodiment, a case where n=2, i.e., two sensors  11 _ 1  and  11 _ 2 , are provided will be described as an example. 
     The work assignment status monitoring apparatus  12  monitors the work assignment status of a monitoring target TG in the facility PL 1 . Here, the monitoring target TG is either the worker  901  or a predetermined mobile body  902   a  which are the monitoring targets whose operations statuses are to be monitored by the work assignment status monitoring apparatus  12 . The predetermined mobile body  902   a , among the mobile bodies  902  detected by the sensors  11 _ 1  and  11 _ 2 , is a vehicle, such as an AGV, or a work robot, which is configured to automatically perform a predetermined work assignment. 
     Specifically, the work assignment status monitoring apparatus  12  includes an acquisition unit  121 , a monitoring target detection unit  122 , a first determination unit  123 , a recording unit  124 , an information generation unit  125 , and an output unit  126 . 
     The acquisition unit  121  acquires information about one or more work areas in the facility PL 1 . The information about the work area includes at least information of a place (a position) where a designated work assignment is performed. The information about the work area may further include a content of the designated work, a minimum time (reference time) required for the designated work, and a maximum work time allowed for the designated work assignment. The acquisition unit  121  may, for example, acquire information about the work area input via an operation terminal by an administrator of the facility PL 1  or the like, or may acquire the information about the work area from results of the detection by the sensors  11 _ 1  and  11 _ 2 . When the sensors  11 _ 1  and  11 _ 2  are cameras, the acquisition unit  121  may acquire the information about the work areas based on results of analyzing videos captured by the cameras. In the example of  FIG.  3   , the acquisition unit  121  acquires information about work areas WA 1  to WA 4  in which places where work assignments are performed are surrounded by frames. The work area WA 3  includes work areas WA 3   a  and WA 3   b.    
     The monitoring target detection unit  122  detects either the worker  901  or the predetermined mobile body  902   a  as the monitoring target TG by using the sensors  11 _ 1  and  11 _ 2 , and defines a monitoring target area TA 1  where the monitoring target TG is positioned. The monitoring target area TA 1  is defined by a frame surrounding the monitoring target TG, and moves along with the movement of the monitoring target TG. In this embodiment, a case where the monitoring target detection unit  122  detects a certain worker  901  as the monitoring target TG will be described, but the present disclosure is not limited to this. Alternatively, the predetermined mobile body  902   a  may be detected as the monitoring target TG, or the worker  901  and the predetermined mobile body  902   a  may be detected as a plurality of the monitoring targets TG. Note that in this embodiment, among the mobile bodies  902  detected by the sensors  11 _ 1  and  11 _ 2 , the moving body (forklift)  902  other than the monitoring target TG are defined as the work area WA 4  where the monitoring target TG performs a work assignment. 
     The first determination unit  123  determines whether or not the monitoring target TG has performed the work in the one or more work areas, which are the work areas WA 1  to WA 4  in the example of  FIG.  3   , based on the presence or absence of interference with the one or more work areas by the monitoring target area TA 1 . For example, when the monitoring target area TA 1  interferes with the work area WA 1 , the first determination unit  123  determines that the monitoring target TG has performed a work in the work area WA 1 . The interference of the monitoring target area TA 1  with the work area WA 1  is not limited to the case where the monitoring target area TA 1  (frame) and the work area WA 1  (frame) partially overlap each other, but also includes the case where the monitoring target area TA 1  (frame) and the work area WA 1  (frame) come to contact with each other. 
     Note that the first determination unit  123  may determine that the monitoring target TG has performed a work in the work area WA 1  when a period of time in which the monitoring target area TA 1  interferes with the work area WA 1  is more than or equal to the minimum time (reference time) required for a work in the work area WA 1 . 
     A result of the determination made by the first determination unit  123  is recorded in the recording unit  124 . The recording unit  124  may be provided inside the work assignment status monitoring apparatus  12  or outside the work assignment status monitoring apparatus  12 . 
     The information generation unit  125  generates information about the work assignment performed by the monitoring target TG in each work area based on the result of the determination made by the first determination unit  123 . The information about the work in the work area includes at least information about a start time, a work time, and an end time of the work assignment performed by the monitoring target TG in each work area. It is also possible to identify a work assignment order when the work assignments are performed in a plurality of work areas from the information of the start time, work time, and end time of the work assignments performed by the monitoring target TG in the respective work areas. 
     The information generated by the information generation unit  125  about the work assignment performed by the monitoring target TG in each work area is recorded (accumulated) in the recording unit  124 . Note that the information about the work assignment performed by the monitoring target TG in each work area may be recorded (accumulated) in the recording unit  124  in a graphed state as described later. 
     The output unit  126  outputs the information about the work assignment performed by the monitoring target TG in each work area generated by the information generation unit  125 . For example, the output unit  126  causes a monitor to display the information (a work assignment pattern) about the work assignment performed by the monitoring target TG in each work area, which is generated by the information generation unit  125 , in a desired display format. 
     Next, an operation of the work assignment status monitoring system  1  will be described with reference to  FIGS.  4  and  5   .  FIG.  4    is a flowchart showing the operation of the work assignment status monitoring system  1 .  FIG.  5    is a schematic plan view showing in more detail the facility PL 1  to which the work assignment status monitoring system  1  is applied. 
     In the work assignment status monitoring system  1 , the work assignment status monitoring apparatus  12  first acquires the information about one or more work areas in the facility PL 1  (Step S 101 ). In the example of  FIG.  5   , the work assignment status monitoring apparatus  12  acquires information about work areas WA 1  to WA 7 , which are places where work assignments are performed, surrounded by a frame. The work area WA 3  includes work areas WA 3   a  and WA 3   b.    
     The work assignment status monitoring apparatus  12  detects the worker  901  as a monitoring target TG by using the sensors  11 _ 1  and  11 _ 2 , and defines a monitoring target area TA 1  where the monitoring target TG is positioned (Step S 102 ). The monitoring target area TA 1  is defined by a frame surrounding the monitoring target TG, and moves along with the movement of the monitoring target TG. One mobile body (forklift) and two AGVs (first and second AGVs), which are the mobile bodies  902  other than the monitoring target TG detected by the sensors  11 _ 1  and  11 _ 2 , are defined as the work areas WA 4 , WA 6 , and WA 7 , respectively, where the monitoring target TG performs works. 
     After that, the work assignment status monitoring apparatus  12  determines whether or not the monitoring target TG has performed work assignments in the work areas WA 1  to WA 7  based on the presence or absence of interference with the work areas WA 1  to WA 7  by the monitoring target area TA 1  (Step S 103 ). The result of determining whether or not the monitoring target TG has performed work assignments in the work assignment areas WA 1  to WA 7  is recorded in the recording unit  124  (Step S 104 ). 
     After that, the work assignment status monitoring apparatus  12  generates information (a work assignment pattern) about the work assignment performed by the monitoring target TG in each of the work areas WA 1  to WA 7  based on the above result of the determination (Step S 105 ), and, for example, displays it on a monitor (Step S 106 ). 
       FIG.  6    shows a first example of the information about work assignments performed by the monitoring target TG output from the work assignment status monitoring apparatus  12 . In the example of  FIG.  6   , a work assignment pattern performed by the monitoring target TG is displayed on the monitor in a two-dimensional graph. In  FIG.  6   , the horizontal axis represents time, and the vertical axis represents the presence or absence of a work assignment performed by the monitoring target TG in each work area. 
     Referring to  FIG.  6   , first, the monitoring target TG performs a work in the work area WA 2  (time t 11  to time t 12 ). After that, the monitoring target TG performs a work in the work area WA 3  (time t 13  to time t 14 ). More specifically, the monitoring target TG first performs a work in the work area WA 3   a  of the work area WA 3  (time t 13   a  to time t 13   b ), and then performs a work in the work area WA 3   b  (time t 14   a  to time t 14   b ). Note that the work assignment status monitoring apparatus  12  can appropriately adjust whether or not the two work assignments in the work areas WA 3   a  and WA 3   b  are displayed separately on the monitor or displayed as one work in the work area WA 3 . After that, the monitoring target TG performs a work in the work area WA 7  (time t 15  to time t 16 ). Here, the work area WA 7  is an area where the second AGV is positioned. Thus, there is a possibility that the monitoring target TG may be loading the second AGV or operating the second AGV. After that, the monitoring target TG performs a work in the work area WA 1  (time t 17  to time t 18 ), continues to perform work assignments in the work area WA 6  (time t 19  to time t 20 ), and continues to perform work assignments in the work area WA 4  (time t 21  to time t 22 ). The work area WA 6  is an area where the first AGV is positioned. Therefore, there is a possibility that the monitoring target TG may be loading the first AGV or operating the first AGV in the work area WA 6 . The work area WA 4  is an area where a forklift is positioned. Therefore, there is a possibility that the monitoring target TG may be loading the forklift or operating the forklift in the work area WA 4 . 
     As described above, the work assignment status monitoring system  1  according to this embodiment determines whether or not the monitoring target TG has performed work assignments in one or more work areas based on the presence or absence of interference (contact) with the one or more work areas by the monitoring target area TA 1  where the monitoring target TG such as a worker is positioned. By doing so, the work assignment status monitoring system  1  according to this embodiment can infer and monitor the work assignment status of the monitoring target TG with a smaller amount of information than that in the case where, for example, the movement of the monitoring target TG is analyzed in detail. That is, the work assignment status monitoring system  1  according to this embodiment can efficiently monitor the work assignment status(es) of one or more designated work assignments performed by the monitoring target TG such as a worker. 
     Note that in this embodiment, in the work assignment status monitoring system  1 , the work assignment status monitoring apparatus  12  is described with reference to an example in which the monitoring target area TA 1  where the monitoring target TG is positioned is defined. However, the present disclosure is not limited to this. That is, the work assignment status monitoring apparatus  12  may be configured to further define a second monitoring target area TA 2  in which a predetermined part of the monitoring target TG, such as a worker&#39;s fingertip who is the monitoring target TG, is positioned. For example, the work assignment status monitoring apparatus  12  determines whether or not the worker&#39;s fingertip, who is the monitoring target TG, has performed work in one or more work areas based on the presence or absence of interference with one or more work areas by the monitoring target area TA 2 . In this manner, the work assignment status monitoring system  1  can more accurately infer the work assignment status of the monitoring target TG. 
     In this embodiment, in the work assignment status monitoring system  1 , the work assignment status monitoring apparatus  12  displays the work assignment pattern performed by the monitoring target TG on the monitor in a display format as shown in  FIG.  6   , but the present disclosure is not limited to this. The work assignment status monitoring apparatus  12  may display the work assignment pattern performed by the monitoring target TG on the monitor in any display format that enables monitoring of the work assignment status of the monitoring target TG. Hereinafter, a brief description will be given with reference to  FIGS.  7  and  8   . 
       FIG.  7    shows a second example of the information about the work assignments performed by the monitoring target TG output from the work assignment status monitoring apparatus  12 . In the example of  FIG.  7   , the work assignment pattern performed by the monitoring target TG is displayed on the monitor in a three-dimensional graph. In  FIG.  7   , the X-axis and Y-axis represent a position (plane coordinate) of the facility PL 1 , and the Z-axis represents the time. By making the resolution of the plane coordinates adjustable, for example, it is possible to allow a selection of whether the two work assignments in the work areas WA 3   a  and WA 3   b  are displayed separately or as one work in the work area WA 3 . As described above, the work assignment status monitoring apparatus  12  may display the work assignment pattern performed by the monitoring target TG on the monitor in a display format as shown in  FIG.  7   . 
       FIG.  8    shows a third example of the information about the work assignments performed by the monitoring target TG output from the work assignment status monitoring apparatus  12 . In the example of  FIG.  8   , the work assignment pattern performed by the monitoring target TG is displayed on the monitor in a display format of an event network. In an event network, an event (work) is represented as a node (a block provided with a name of a work area where the work is performed), and an event and a subsequent event are connected to each other by an edge (line segment). As described above, the work assignment status monitoring apparatus  12  may display the work assignment pattern performed by the monitoring target TG on the monitor in a display format as shown in  FIG.  8   . As the display format, a Petri net may be used instead of an event network. 
     Second Embodiment 
       FIG.  9    is a block diagram showing a configuration example of a work assignment status monitoring system  2  according to a second embodiment. As compared with the work assignment status monitoring system  1 , the work assignment status monitoring system  2  includes a work assignment status monitoring apparatus  22  in place of the work assignment status monitoring apparatus  12 . As compared with the work assignment status monitoring apparatus  12 , the work assignment status monitoring apparatus  22  further includes a normal state decision unit  227 , a second determination unit  228 , and a prediction unit  229 . The other components of the work assignment status monitoring apparatus  22  are the same as those of the work assignment status monitoring apparatus  12 , and therefore description thereof will be omitted. 
     (Determination Function of Work assignment status Monitoring Apparatus  22 ) 
     First, the determination function of the work assignment status monitoring apparatus  22  will be described with reference to  FIGS.  9  and  10   .  FIG.  10    is a flowchart showing a determination operation performed by the work assignment status monitoring apparatus  22 . 
     In the work assignment status monitoring apparatus  22 , the information generation unit  125  generates a plurality of pieces of information about the work assignments performed by the monitoring target TG as a result of repeatedly monitoring the work assignment status of the work assignments performed by the monitoring target TG in the facility PL 1 . The plurality of pieces of information about the work assignments performed by the monitoring target TG generated by the information generation unit  125  are recorded (accumulated) in the recording unit  124  as a plurality of work assignment histories (Step S 201 ). 
     In the work assignment status monitoring apparatus  22 , the normal state decision unit  227  performs learning using the plurality of work assignment histories recorded in the recording unit  124  (Step S 202 ), and decides a normal state of the work assignment performed by the monitoring target TG based on a result of the learning (Step S 203 ). For example, the normal state decision unit  227  decides the normal state as a statistical model using a function shape and a network assignment pattern as a random variable. The normal state for the work assignment performed by the monitoring target TG is, for example, a normal (average) work time in each work area and a normal work assignment order performed by the monitoring target TG. Note that the normal state of the work assignment performed by the monitoring target TG is not limited to one type, and may be classified into two or more types. 
     Here, as a result of monitoring the status of the work assignment newly performed by the monitoring target TG, when new information (a newly performed work assignment pattern) about the work assignment performed by the monitoring target TG is generated by the information generation unit  125  (Step S 204 ), the output unit  126  outputs the new information about the work assignment performed by the monitoring target TG (the newly performed work assignment pattern) together with the result of a comparison between the new information about the work assignment performed by the monitoring target TG and the information about the work assignment in the normal state (a work assignment pattern in the normal state) (Step S 205 ). 
     Note that output unit  126  may be configured to output the new information about the work assignment performed by the monitoring target TG (the newly performed work assignment pattern) in a highlighted manner in accordance with the degree of deviation from the information about the work assignment in the normal state (the work assignment pattern in the normal state) to output the new information about the work assignment performed by the monitoring target TG. For example, if the work time in the work area WA 1  included in the newly performed work assignment pattern is longer than the work time in the work area WA 1  included in the work assignment pattern in the normal state, the output unit  126  may cause the corresponding part to flash and be displayed or may cause the corresponding part to be displayed in a color different from colors of the other parts. 
     In the work assignment status monitoring apparatus  22 , the second determination unit  228  determines whether or not the new information about the work assignment performed by the monitoring target TG (the newly performed work assignment pattern) is included in a range of the normal state based on the degree of deviation of the new information about the work assignment performed by the monitoring target TG from the information about the work assignment performed in the normal state (the work assignment pattern in the normal state). A method such as statistical divergence is used to measure the degree of deviation. The output unit  126  may further output a result of the determination made by the second determination unit  228 , which is, information as to whether or not the newly performed work assignment pattern is included in the range of the work assignment pattern in the normal state. 
     As described above, the work assignment status monitoring system  2  can set the normal state of the work assignment order, the work time, and the like for each of the monitoring targets TG. It is thus possible to present whether or not the normal state for the worker who is the monitoring target TG is the normal state for the worker who is the monitoring target TG, for example, even when the work time of a certain work assignment performed by the worker who is the monitoring target TG is longer than those of other workers due to differences in experience and skill. 
     (Prediction Function of Work Assignment Status Monitoring Apparatus  22 ) 
     Next, a prediction function of the work assignment status monitoring apparatus  22  will be described with reference to  FIGS.  9  and  11   .  FIG.  11    is a flowchart showing a predicted operation performed by the work assignment status monitoring apparatus  22 . 
     In the work assignment status monitoring apparatus  22 , the information generation unit  125  generates a plurality of pieces of information about the work assignments performed by the monitoring target TG as a result of repeatedly monitoring the work assignment status of the work assignments performed by the monitoring target TG in the facility PL 1 . The plurality of pieces of information about the work assignment performed by the monitoring target TG generated by the information generation unit  125  are recorded (accumulated) in the recording unit  124  as a plurality of work assignment histories (Step S 301 ). 
     In the work assignment status monitoring apparatus  22 , the normal state decision unit  227  performs learning using the plurality of work assignment histories recorded in the recording unit  124  (Step S 302 ), and decides a normal state of the work assignment performed by the monitoring target TG based on a result of the learning (Step S 303 ). For example, the normal state decision unit  227  decides the normal state as a statistical model using a function shape and a network pattern as a random variable. The normal state for the work assignment performed by the monitoring target TG is, for example, a normal (average) work time in each work area and a normal work assignment order performed by the monitoring target TG. Note that the normal state of the work assignment performed by the monitoring target TG is not limited to one type, and may be classified into two or more types. 
     Here, in the work assignment status monitoring apparatus  22 , the prediction unit  229  analyzes the degree of deviation of the plurality of pieces of information about the work assignments performed by the monitoring target TG (a plurality of work assignment patterns performed in the past) recorded as the plurality of work assignment histories in the recording unit  124  from the information (the work assignment patterns in the normal state) about the work assignment in the normal state (Step S 304 ). Next, the prediction unit  229  predicts information (the work time and the work assignment order) about the work assignment likely to exceed the range of the normal state among the work assignment patterns to be performed by the monitoring target TG in the future (Step S 305 ). 
     For example, if there are a relatively large number of work assignment patterns including a specific work assignment in which the work time exceeds the range of the normal state among the plurality of work assignment patterns performed in the past, the prediction unit  229  predicts that the work time of the specific work assignment may exceed the range of the normal state among the plurality of work assignments included in the work assignment pattern to be performed by the monitoring target TG in the future. 
     The output unit  126  outputs a result of the prediction made by the prediction unit  229  (Step S 306 ). For example, the output unit  126  outputs information indicating that among a plurality of work assignments included in a work assignment pattern to be performed by the monitoring target TG in the future, the work time of a specific work assignment may exceed the range of the normal state. Alternatively, the output unit  126  may output a predicted value of the work assignment pattern to be performed by the monitoring target TG in the future together with a result of the comparison between the predicted value of the work assignment pattern to be performed by the monitoring target TG in the future and the information about the work assignment in the normal state (the work assignment pattern in the normal state). 
     As described above, since the work assignment status monitoring system  2  can predict the work assignment that may exceed the range of the normal state for each monitoring target TG, for example, a warning can be given in advance to the worker who is the monitoring target TG. 
     Other components and operations of the work assignment status monitoring system  2  are the same as those of the work assignment status monitoring system  1 , and therefore description thereof will be omitted. 
     As described above, the work assignment status monitoring system  2  according to this embodiment can achieve the effect equivalent to that of the work assignment status monitoring system  1 . Furthermore, the work assignment status monitoring system  2  according to this embodiment can set a normal state for the work assignment order, the work time, etc., for each monitoring target TG. Therefore, for example, even if the work time of a certain work assignment performed by a worker who is the monitoring target TG is longer than those of other workers due to a difference in experience or skill, it is possible to present whether or not it is a normal state for the worker who is the monitoring target TG. Moreover, since the work assignment status monitoring system  2  according to this embodiment can predict a work assignment that may exceed the range of the normal state for each monitoring target TG, for example, a warning can be given in advance to the worker who is the monitoring target TG. 
     Note that the work assignment status monitoring apparatus  22  may have only one of the determination function and the prediction function. 
     In addition, the work assignment status monitoring apparatus  22  may define a predetermined work assignment pattern as a work assignment pattern in an abnormal state. By doing so, when the predetermined work assignment pattern is about to be performed by the monitoring target TG, the work assignment status monitoring apparatus  22  can warn not to perform the predetermined work assignment pattern. 
     Further, the work assignment status monitoring apparatus  22  may decide the normal state after creating a DSM (Design Structure Matrix) from work assignment histories recorded in the recording unit  124 . A brief description will be given below with reference to  FIGS.  12  to  15   . 
       FIGS.  12  to  14    are diagrams in which three event networks classified from a plurality of work assignment histories and work assignment procedures of a plurality of events on the event networks are displayed in a matrix. In the examples of the event networks shown in  FIGS.  12  to  14   , it is assumed that events (designated work assignments) occur in alphabetical order. Further, in the examples of the event networks shown in  FIGS.  12  to  14   , the solid arrows represent procedures of prerequisite work assignments performed by the monitoring target TG, and the dashed arrow represents reworking in a work assignment procedure performed by the monitoring target TG. The “X” displayed in the matrix represents procedures corresponding to the arrows of the event networks. 
     When the work assignment status monitoring apparatus  22  accumulates “X” appearing in each matrix among the matrix components shown in  FIGS.  12  to  14   , a probability distribution can be defined on a matrix shown in  FIG.  15   , and this probability distribution can be decided as the normal state of the work assignment procedure performed by the monitoring target TG. 
     The present disclosure is not limited to the above-described embodiments, and may be suitably modified without departing from the spirit. 
     Further, the present disclosure can be implemented by causing a Central Processing Unit (CPU) to execute a computer program in part or in whole of the processing of the work assignment status monitoring apparatuses  12  and  22 . 
     The above program includes instructions (or software codes) that, when loaded into a computer, cause the computer to perform one or more of the functions described in the embodiments. The program may be stored in a non-transitory computer readable medium or a tangible storage medium. By way of example, and not a limitation, non-transitory computer readable media or tangible storage media can include a random-access memory (RAM), a read-only memory (ROM), a flash memory, a solid-state drive (SSD) or other types of memory technologies, a CD-ROM, a digital versatile disc (DVD), a Blu-ray disc or other types of optical disc storage, and magnetic cassettes, magnetic tape, magnetic disk storage or other types of magnetic storage devices. The program may be transmitted on a transitory computer readable medium or a communication medium. By way of example, and not a limitation, transitory computer readable media or communication media can include electrical, optical, acoustical, or other forms of propagated signals. 
     From the disclosure thus described, it will be obvious that the embodiments of the disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.