Patent Publication Number: US-2016239552-A1

Title: Data Display System

Description:
TECHNICAL FIELD 
     The present invention relates to a data display system that displays a temporal change of data relating to a certain item. 
     BACKGROUND ART 
     In order to cause machinery such as a gas engine, an elevator, or mining and construction machinery to continuously operate, a maintenance operation of machinery is necessary. One of the technologies which is effective as a maintenance operation is a method of collecting sensor data (detected value) of plural sensors attached to respective portions of machinery, performing disorder diagnosis of the machinery from the collected sensor data, and performing cause analysis thereof when there is a disorder. 
     As a method of diagnosing a disorder using this technique, there is a method of expressing distribution of sensor data of machinery or occurrence frequency with a graph such as a scatter diagram or a histogram and examining a disorder of the machinery based on an outlier which is greatly deviated from other values in the graph. In this method, when an outlier occurs, it is assumed that a disorder is generated in the machinery, but it is necessary to specify a cause of the disorder by inspecting what is the actual cause of generation of the outlier. In order to specify the cause of the generation of the outlier, it is necessary to analyze temporal changes of sensor data, when the outlier occurs. However, in order to obtain a time waveform when the outlier occurs from a histogram or a scatter diagram, an operation of specifying time of the generation of a desired outlier and reading a time waveform of the generation time is necessary. If this operation is performed at each time of inspecting an outlier, there is a concern in that the efficiency of the inspection greatly decreases. 
     Examples of a data display device in which this problem is solved include JP-A-7-282277. In the literature, among a generation number of defects A to E and a total number of the defects of machinery on a predetermined date (for example, May 16), a ratio of occupying respective defects A to E is displayed on a screen with a pareto graph, and an analyst is caused to select the defects A to E that are desired to be displayed in time series of the generation number for a predetermined period. Also, based on only a simple operation of selection by an analyst, time series of the generation number of the selected defects for a predetermined period are displayed with a bar graph (trend chart). A horizontal axis in the bar graph indicates date, and a predetermined date (for example, May 1 to 16) including a predetermined date used in a pareto graph initially as the date is set. Accordingly, a pareto graph indicating cross-sectional characteristics in a time axis and a trend chart indicating characteristics in a time axis are organically bonded, and thus changes in time series of respective data can be easily recognized. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: JP-A-7-282277 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the invention relating to the literature, a desired defect is selected from a bar graph (pareto graph) indicating the generation number of plural defects relating to the predetermined date, and a bar graph indicating the generation number of defects for several days including the predetermined day with respect to the selected defect is displayed. Therefore, changes in the generation numbers of the defects for each day are easily recognized. However, in case an outlier having a predetermined tendency in a period of time shorter than one day (for example, a short period of time from about several seconds to several hours) occurs, the changes may not be known by using graphs indicating the generation number of defects per day in many cases, and thus cause analysis becomes difficult. For example, according to defects, outliers are collectively generated for a short period of time, and outliers having the same tendency as the set of the outliers may be generated plural times with an interval. Therefore, the technique of the literature is not appropriate for the analysis of this type of defect. 
     In addition, in order to deal with outliers generated for a short period of time, it is considered to solve the problem described above by setting a unit of a horizontal axis (time axis) of a graph in time series of the generation number of defects in the technique above to a value less than one day (for example, minutes or hours). However, in this technique without change, an operation of specifying time at which the outlier is generated from the graph in time series and an operation of extracting and comparing the corresponding portion are required, and thus there is a concern in that a defect analysis operation may be delayed. 
     Further, the invention is not limited to the outliers exemplified above, but it is desirable to easily recognize an aspect of the temporal change of a portion of data (partial set) included in a set of data of a certain item that is associated with the time. 
     An object of the invention is to provide a data display system in which, in case a portion of data (partial set) included in a set of data relating to a certain item is generated for a short period of time from several seconds to several hours, an aspect of temporal changes of data relating to a certain item or other items around the time at which the portion of data is generated can be easily recognized. 
     Solution to Problem 
     The invention includes plural items of means for solving the problem described above. An example thereof includes a data display system relating to the invention including a storage device that stores data relating to a plurality of items in association with respective times; a display device that displays a first graph indicating distribution of data relating to one item of the plurality of the items; an input device that designates a portion of data included in the distribution of the data indicated in the first graph; and a processing device that performs a first process of dividing times to be associated with the portion of data designated by the input device into a plurality of groups based on intervals of respective times, a second process of searching the data relating to desired items included in time ranges regulated by first and last times respectively included in the plurality of groups from the storage device, and a third process of displaying a second graph indicating temporal changes of the data relating to the desired items based on the search results on the display device for each of the plurality of time ranges. 
     Advantageous Effects of Invention 
     According to the invention, by designating an item of which temporal changes around a time of generation of a portion (partial set) of a set of data relating to a certain item are desired to be known, it is possible to easily recognize an aspect of temporal changes around the generation time of data relating to the designated item. Accordingly, for example, also in case outliers are generated for a short period of time from several seconds to several hours, a time waveform graph is displayed for a short period of time around the generation time, and thus a main cause of the outliers can be analyzed from the waveform when the outliers are generated. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating an object of the invention. 
         FIG. 2  is a diagram illustrating a subject of the invention. 
         FIG. 3  is a diagram illustrating a principle of the invention. 
         FIG. 4  is a diagram illustrating an entire configuration of a data display system relating to an embodiment of the invention. 
         FIG. 5  is a diagram illustrating a configuration of a table T 1  stored in a sensor database  410 . 
         FIG. 6  is a diagram illustrating a configuration of another table T 7  stored in the sensor database  410 . 
         FIG. 7  is a functional block diagram illustrating the data display system relating to the embodiment of the invention. 
         FIG. 8  is a sequence diagram illustrating a flow of processes performed in respective portions illustrated in  FIG. 7 . 
         FIG. 9  is a diagram illustrating a first selection screen displayed on a display device  440  in S 505  of  FIG. 8 . 
         FIG. 10  is a diagram illustrating a configuration of a table T 2  in which sensor data loaded in a storage device  450  from the table T 1  in S 510  of  FIG. 8  is stored. 
         FIG. 11  is a scatter diagram created in S 515  of  FIG. 8 . 
         FIG. 12  is a diagram illustrating a configuration of a table T 3 . 
         FIG. 13  is a diagram illustrating a configuration of a table T 4 . 
         FIG. 14  is a flowchart illustrating internal processes performed in S 535  of  FIG. 8 . 
         FIG. 15  is a diagram illustrating a second selection screen displayed on a display device  440  in S 538  of  FIG. 8 . 
         FIG. 16  is a diagram illustrating a configuration of a table T 5 . 
         FIG. 17  is a diagram illustrating a configuration of a table T 6 . 
         FIG. 18  is a flowchart illustrating an internal process S 545 _SUB performed in S 545  of  FIG. 8 . 
         FIG. 19  is a flowchart illustrating a subroutine S 545 _SUB 2  in an internal process illustrated in  FIG. 18 . 
         FIG. 20  is a diagram illustrating an example of a screen which is created in S 550  and displayed in S 555  of  FIG. 8 . 
         FIG. 21  is a diagram illustrating another example of a time waveform included in a screen displayed in S 555  of  FIG. 8 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First, before an embodiment of the invention is described in detail, the basic concept of the embodiment described below is described.  FIG. 1  is an example of a scatter diagram illustrating the relationship between engine pressure and the number of engine rotations which are detected in a predetermined period with a pressure sensor and a rotation number sensor in machinery in which an engine is installed. In the scatter diagram, a set  100  of an outlier exists as a partial set of sensor data. In this method, it is assumed that a disorder may occur in the machinery when an outlier occurs. As illustrated in an area  110  of a broken line in  FIG. 1  in order to specify the cause of the generation of the outlier, sensor data (the number of engine rotations) with respect to the time when the outlier included in the set  100  occurs is analyzed based on the graph (time waveform) illustrating a temporal change of the sensor data. 
     In the technique disclosed in JP-A-7-282277, a desired defect is selected from a bar graph (pareto graph) indicating the number of plural generated defects relating to the predetermined day, and a bar graph indicating the number of generated defects in several days including the corresponding predetermined day with respect to the selected defects is disclosed. However, as illustrated in  FIG. 2 , in case a set  200  of outliers is continued for a short period of time of several seconds to several minutes as in an area  210  of a broken line, even if a graph illustrating the number of generated defects per day is used, it is difficult or it is not possible to know the cause. 
     (1) Therefore, the data display system according to the present embodiment include a storage device (for example, a magnetic storage device such as a hard disk drive and a semiconductor memory such as a flash memory) in which data according to plural items (for example, engine pressure and the number of engine rotations) in association with respective times is stored, a display device (for example, a monitor) displaying a first graph (for example, a scatter diagram or a histogram) indicating the distribution of data relating to one item among the plural items, an input device (for example, a mouse, a keyboard, or a touch panel) to which a portion of data included in the distribution of the data illustrated in the first graph is designated, and a processing device (for example, CPU) that performs a first process of dividing the times associated with the portion of the data designated by the input device into plural groups based on intervals of respective times, a second process of searching data relating to the desired items (for example, the number of engine rotations) included in the time range designated in the first and last times respectively included in the corresponding plural groups from the storage device, and a third process of displaying a second graph (for example, time waveform of the number of engine rotations) indicating a temporal change of the data corresponding to the desired item based on the search result on the display device in each of the plural time ranges. 
     Accordingly, the times associated with the portion of the data designated by the input device can be automatically divided into plural groups based on the intervals of the respective times (for example, times which have intervals less than a predetermined threshold value are classified into the same group). Since a graph (second graph) indicating temporal changes of data relating to desired items with respect to the time range regulated by first and last times included in respective groups is created and displayed, aspects or tendencies of temporal changes of respective data relating to times at which a portion of the data designated on the first graph occurs can be easily recognized on the display device by using the input device. However, for example, even in a case where outliers are generated for a short period of time from several seconds to several hours, a time waveform of data of a desired item for the short period of time around the generation time is displayed, and thus a main cause of the outliers can be analyzed based on the time waveform. 
     Further, actions and effects of the present embodiment with reference to an example illustrated in  FIG. 3  are described as follows. In the example of  FIG. 3 , a scatter diagram (see a graph on the left end of  FIG. 3 ) obtained by storing the number of engine rotations and the engine pressure which are values detected by a rotation number sensor and a pressure sensor in the storage device in association with the detection time and causing distribution of data of the number of engine rotations to be associated with the data of the engine pressure is displayed on the display device. If an analyst (operator) reads the scatter diagram and selects a set  300  of outliers via an input device such as a mouse, the processing device sorts times which correspond to the outliers in a time series order, and divides the times into plural groups based on intervals of respective times (see graphs on upper right of  FIG. 3 ). Also, the processing device defines time ranges of respective groups based on first and last times included in the respective groups and searches the numbers of engine rotations included in the respective time ranges from the storage device. Further, the processing device creates temporal changes of the number of engine rotations for each of the time ranges (for each of the groups) based on the search result. In the examples of  FIG. 3 , the times sorted in a time series order are aggregated in types having close intervals and divided into three groups, and three time waveforms  310 ,  320 , and  330  are created based on the data of the number of engine rotations included in the time ranges of the respective groups. Accordingly, the analyst can simply select a set of outliers in the data of the number of engine rotations on the first graph so as to obtain time waveforms automatically grouped based on the detection times of the selected outliers. Therefore, it is possible to easily recognize which changes are generated in the machinery at the time at which the outliers are generated. 
     (2) According to the present embodiment, it is preferable that a process of comparing shapes of second graphs for respective groups, grouping the graphs having similar shapes, and displaying the graphs on the display device is performed by the processing device. Accordingly, graphs having similar shapes among the plural second graphs are grouped and displayed to the analyst, and thus graphs that repeatedly occur among the plural second graphs can be easily specified. Therefore, the display screen is useful for assuming the cause of the generation of the data selected on the first graph. 
     With respect to the characteristics, in the example of  FIG. 3 , since the two waveforms  320  and  330  are similar to each other among the three time waveforms  310 ,  320 , and  330  of the number of engine rotations based on the set of the outliers of the engine pressure and the number of engine rotations, backgrounds of the two waveforms and a background of the rest one waveform are displayed to be different from each other. That is, the background of a display waveform  315  relating to the waveform  310  is white, and backgrounds of display waveforms  325  and  335  relating to the waveforms  320  and  330  are hatched. For example, in this case, since two waveforms of the waveform  325  and the waveform  335  which are similar to each other are generated while one waveform of a waveform  315  is generated, the analyst can consider that the main cause of the outliers is related to the waveform  325  and the waveform  335 . In addition, in view of the waveforms  325  and  335  and the generation time range thereof, the analyst can assume that the phenomenon occurred immediately after the start of the machinery, and the cause of the generation of the outliers is the engine pressure and the number of rotations which are lower than those in a normal operation of the machinery. 
     (3) In addition, before the first graph is displayed on the display device, a process of displaying a screen (first selection screen) for selecting an item for displaying the first graph among the plural items on the display device may be performed, and a process of displaying the distribution of data relating to the item selected through the screen (first selection screen) by the input device as the first graph may be performed by the processing device. Accordingly, the first graph relating to the desired item of the analyst can be displayed on the display device. 
     In addition, at this point, setting may be performed such that selecting types of the graphs to be displayed as the first graph and setting of the indexes required for the display of selected types the graphs can be performed on the first selection screen. For example, types of the graphs displayed as the first graph include a scatter diagram or a histogram. In the case of a scatter diagram, items for setting a vertical axis and a horizontal axis of the graph are required to be selectable on the first selection screen. 
     (4) In addition, before the second process, a process of (fourth process) displaying a screen (second selection screen) for selecting an item for which the data is searched from the storage device in the second process from the plural items is performed, and a process of searching data included in the plural time range among the data relating to the items selected in the fourth process as the second process from the storage device may be performed by the processing device. 
     Accordingly, an item to be displayed as a first graph and an item to be displayed as a second graph can be varied. For example, in case there are plural sensors measuring different states in the same portion of the machinery, if temporal changes of values detected by the plural sensors are respectively examined around the time at which outliers are generated, a cause that may not be proved only by a value detected by one sensor is proved in some cases. Specifically, in case a cause of outliers is not known even if a time waveform (second graph) with respect to the outliers of the engine temperature sensor is referred to, if a time waveform of a detected value of a pressure sensor for detecting engine pressure closely associated with an engine temperature is displayed, a cause of the outliers can be further searched. In addition, the “item” displayed in the second graph may be formed by displaying a selection screen (second display screen) each time such that one of the plural items is selected or may be set in advance. 
     Hereinafter, the embodiment of the invention is described in detail by using the drawings.  FIG. 4  is a diagram illustrating the entire configuration of the data display system according to the embodiment of the invention. The data display system illustrated in  FIG. 4  includes a sensor database  410 , a processing device  445 , an input device  425 , a storage device  450 , and a display device  440 . 
     The sensor database  410  is a database that stores sensor data (for example, engine pressure or the number of rotations) measured by various sensors installed in machinery such as railway or construction machinery. 
       FIG. 5  is a diagram illustrating the configuration of a table T 1  stored in the sensor database  410 . In the table T 1  illustrated in  FIG. 5 , detected values (sensor data) of the plural sensors are stored, plural sensor data  815 ,  820 , and  825  and measuring times  810  thereof are stored in an associated manner, and sensor data in an arbitrary time range are configured in a searchable manner. 
       FIG. 6  is a diagram illustrating the configuration of a table T 7  stored in the sensor database  410 . The table T 7  is a table in which information of a set of sensors which are closely associated with each other is stored. The closely associated sensors refer to a set of sensors measuring states of the same component, for example, a temperature sensor or a pressure sensor of an engine or a set of sensors that measures values interlocked to each other, such as an atmospheric temperature and an engine temperature. 
     For example, sensors of engine pressure on the first row of  1320  of T 7  and an exhaust gas temperature of  1330  are sensors that indicate states of the same engine and are closely associated with each other. The cause of an outlier that may not be searched for with one sensor can be found out by examining waveforms of the closely associated sensors. For example, in case the cause of an outlier is not known even if a time waveform of a temperature sensor is referred to, the cause of the outlier can be further searched by subsequently referring to a time waveform of a pressure sensor closely associated with the temperature sensor. The closely associated sensor is decided based on hearing from a designer of the machinery or information of design specifications. 
     The processing device  445  is a device that includes a CPU or the like and performs an operation relating to various processes according to the present embodiment. The display device  440  includes a liquid crystal display or the like and displays a scatter diagram (first graph) or a time waveform (second graph) created by an occurrence frequency information creating portion  415  or a time waveform data creating portion  420  described below. The storage device  450  is a device that primarily and continuously stores various kinds of data together with programs for causing the processing device  445  to perform various processes, and includes a semiconductor memory such as ROM, RAM, and a flash memory or a magnetic storage device such as a hard disk drive. For example, tables T 2  to T 6  described below are stored in the storage device  450 . The input device  425  includes a device such as a mouse, a keyboard, or a touch panel and enables a user to designate data or a sensor from a scatter diagram (first graph) or a table displayed on the display device  440 . 
     In addition, the processing device  445 , the display device  440 , the storage device  450 , the input device  425 , and the database  410  may be installed in the same computer (calculator) or different computers. In the former case, all the devices  445 ,  440 ,  450 ,  425 , and  410  or a computer in which functions of the devices (data display devices) are installed becomes the embodiment of the invention. Meanwhile, in the latter case, a computer in which the database  410  is installed and a computer in which the other devices are installed needs to be configured to perform transmission and reception of the data by being connected to each other via a network  416  such as a LAN or the Internet. Further, the computers may have a system configuration that performs a main process relating to a data display described below on the side of a server connected to the network and causes a client computer to instruct an operation to the server and acquire a corresponding calculation result. That is, the invention can exhibit the effect thereof, wherever the respective devices  445 ,  440 ,  450 ,  425 , and  410  are installed. 
       FIG. 7  is a functional block diagram of a data display system according to the embodiment of the invention. As illustrated in  FIG. 7 , the data display system according to the present embodiment functions as the occurrence frequency information creating portion  415 , the time waveform data creating portion  420 , a data aggregating portion  430 , and a similar waveform searching portion  435 . 
     The occurrence frequency information creating portion  415  is a portion that reads sensor data of designated time ranges or types from the sensor database  410  and performs a process of creating a scatter diagram (first graph). The time waveform data creating portion  420  is a portion that reads sensor data of designated time ranges and types from the sensor database  410  and creates a time waveform (second graph). The data aggregating portion  430  is a portion that groups (aggregates) time information  913  to  918  in various portions of the table T 3  and stores the resulting time ranges in the table T 4 . The contents of the detailed processes of the data aggregating portion  430  are described below with reference to  FIG. 14 . The similar waveform searching portion  435  is a portion that groups a similar time waveform of the sensor data from the table T 5  and performs a process of storing the result in the table T 6 . Detailed processes of the similar waveform searching portion  435  are described below with reference to  FIGS. 18 and 19 . 
     Subsequently, with reference to  FIG. 8 , a flow of the process performed in the present embodiment is described.  FIG. 8  is a sequence diagram illustrating a flow of the overall processes performed by respective portions illustrated in  FIG. 7  and illustrates internal processes performed in the respective portions and data input and output between respective portions in a sequential order. In addition,  FIG. 8  illustrates the overall flow of the processes performed in the present embodiment in steps of S 505  to S 555 . The processes performed in the respective steps are described below. 
     In S 505 , a screen (first selection screen) that enables a user (analyst) to select sensor data for creating a scatter diagram (first graph) is displayed on the display device  440 .  FIG. 9  is a diagram illustrating a first selection screen displayed on the display device  440  in S 505 . The first selection screen illustrated in  FIG. 9  includes the sensor selecting portion  605  that selects a sensor to be displayed as a horizontal axis of a scatter diagram, a sensor selecting portion  610  that displays a sensor to be displayed as a vertical axis of a scatter diagram, a starting time setting portion  615  that decides a starting time in the measured time range of the sensor data displayed in the scatter diagram, and an ending time setting portion  620  that decides an ending time in the measured time range. 
     A method of selecting a sensor by the sensor selecting portions  605  and  610  may be a method of preparing a pull-down menu displaying a list of names of sensors in which sensor data are stored in the sensor database  410  and select a sensor from the pull-down menu. In addition, names of sensors may be directly input to the sensor selecting portions  605  and  610  with a keyboard. In addition, a method of setting the time by the starting time setting portion  615  and the ending time setting portion  620  includes a method of directly inputting times with a keyboard. If the names of the sensors and starting and ending times are completely input, when a user presses a button  625  for displaying a scatter diagram, the process proceeds to a process of S 510  for creating a scatter diagram. 
     In S 510 , in the sensor data relating to the table T 1  ( FIG. 5 ) of the database  410 , the sensor designated by the user and the sensor data of the time range are loaded in the storage device  450 , in S 505 .  FIG. 10  is a diagram illustrating a configuration of the table T 2  storing sensor data loaded in the storage device  450  from the table T 1  in S 510 . As illustrated in  FIG. 10 , the data loaded in the storage device  450  are stored in the table T 2 , in a set of two sensors (engine pressure and the number of engine rotations)  835  and  840  designated in S 505  and sensor measurement times  830  corresponding thereto. 
     In S 515 , the occurrence frequency information creating portion  415  creates a scatter diagram from the table T 2 .  FIG. 11  is a scatter diagram created in S 515 . In S 515 , specifically, values of the two sensors  835  and  840  from the first to last rows of the table T 2  are illustrated on the scatter diagram of  FIG. 11 . In the examples of  FIG. 11 , values of the engine pressure  835  are illustrated on the vertical axis and the numbers of engine rotations  840  are illustrated on the horizontal axis, so as to create a scatter diagram. 
     In S 520 , the scatter diagram created in S 515  is displayed on the display device  440  and is presented to the user. This process is automatically performed by causing the occurrence frequency information creating portion  415  to illustrate the scatter diagram on a liquid crystal display in S 515 . 
     In S 525 , a process of displaying a cursor  705  that can move on a screen by an operation of the input device  425  on a scatter diagram of S 520  and causing the user to select plural data dots with the cursor  705  is performed. The user can move the cursor  705  along a track such as a dotted line  720  so as to select plural data dots at once surrounded by the track. The selected plural data dots are dots that the user desires to examine for the cause of the generation such as an outlier on the scatter diagram. In addition, another method of selecting the data dots on the scatter diagram is a method of drawing a rectangle having a diagonal line in a direction in which a mouse is dragged on a scatter diagram and selecting plural data dots existing inside the rectangle. In addition, well-known selection methods such as a method of clicking all data dots that the user desires to select with a mouse can be used. 
     In S 530 , a process of searching a time (sensor measurement time) associated with plural data dots selected in S 525  from the table T 2  ( FIG. 10 ), summarizing the results in the table T 3 , and storing the table T 3  in the storage device  450  is performed.  FIG. 12  is a diagram illustrating a configuration of the table T 3 . As illustrated in  FIG. 12 , the table T 3  only includes time data. In order to create the table T 3 , the time  830  of the table T 2  ( FIG. 10 ) is searched by using values of the engine pressure and the number of engine rotations relating to the plural data dots selected on the scatter diagram of  FIG. 11  as searching keys. The time list of the search result is stored in time  910  of the table T 3  in a column order. 
     In S 535 , as preparation for creating a time waveform of sensor data to be selected in S 538  later, plural time data stored in the table T 3  is grouped according to the size of the interval of time. The time data included in the respective groups includes data indicating the earliest time and data indicating the latest time, but the times relating to the two groups of data determine the time ranges of the respective time waveforms displayed in S 555 . 
     In grouping of time waveforms (similar waveforms) having shapes similar to each other which is one of the characteristics of the present embodiment, it is necessary to extract a portion of time waveforms that is an analysis target among time waveforms of certain sensor data. In order to extract the portion of the time waveforms, it is necessary to determine the time ranges of the portion of the time waveforms. Therefore, according to the present embodiment, among time data stored in the table T 3 , the time ranges of the portion of the time waveform is decided by grouping (aggregating) types of which the times are close to each other. For example, in the table T 3 , the time data of 10:20:43 to 10:23:05 is grouped (aggregated) as the first group  913 . The starting times and the ending times of the respective time ranges grouped are stored in the table T 4 . 
       FIG. 13  is a diagram illustrating the configuration of the table T 4 . As illustrated in  FIG. 13 , sets of starting times  920  and ending times  930  of respective groups are stored in the table T 4 . Data stored in a first row  923  of the table T 4  indicate the time range of the first group  913  of the table T 3 . In the same manner as the case where the first group  913  is decided from the time data of the table T 3 , in case data having close data values (times) are grouping, techniques in the related art are used. For example, as the techniques in the related art, clustering in the data mining technology can be used. In the present embodiment, more simple examples are used. Specifically, a method in which, in case the time interval of the two time data adjacent to each other in the time data sorted in time series is equal to or less than the threshold value, the two time data are caused to be in the same group is used. Subsequently, this method is described by using  FIG. 14 . In addition, the threshold value of the time interval is determined when the present system is decided and is simply referred to as a threshold value according to the present embodiment. 
       FIG. 14  is a flowchart illustrating the internal process performed in S 535  of  FIG. 8 . In other words,  FIG. 14  illustrates a flow of grouping time information of the table T 3  and storing the results thereof in the table T 4 . First, in S 1410 , a storage area of the counter variable n is prepared in the storage device  450 . This counter variable n is a variable indicating the number of rows in the data of the table T 3 . The counter variable n starts from n=1 and n increases one by one until n reaches the row numerical value relating to the last row of the table T 3 . 
     In S 1420 , the n-th row time is read from the table T 3  and is stored in the starting time  920  of the table T 4 . Specifically, in the case of n=1, data (2013 Mar. 3 10:20:43) relating to the first row of the table T 3  are stored in the column  920  of the starting time on the first row  923  of the table T 4 . 
     In S 1430 , a time interval ΔT between the n-th row and the n+1-th row of the table T 3  is calculated. For example, in the case of n=1, the first row and the second row of T 3  become “2013 Mar. 3 10:20:43” and “2013 Mar. 3 10:22:05”, and thus the time interval ΔT between the both becomes 22 seconds. 
     In S 1440 , whether the time interval ΔT calculated in S 1430  is equal to or greater than the threshold value determined at the time of designing the system is determined. If the time interval ΔT is equal to or greater than the threshold value, it is determined that the times in the n-th row and the n+1-th row of the table T 3  are boundaries of the two time waveforms, and the process proceeds to S 1450 . Otherwise, if the time interval ΔT is less than the threshold value, it is considered that the times in the n-th row and the n+1-th row are times to be included in one time waveform, and the process proceeds to S 1480  in order to continue the grouping process. For example, in case the threshold value is ten minutes, when the time interval ΔT is 22 seconds as described above, the time interval ΔT is smaller than the threshold value, and thus the process proceeds to S 1480 . 
     In S 1480 , the counter variable n is updated to n+1 in order to cause the time in the n-th row to be in the same group on the n−1-th row and refer to the subsequent time on the n+1-th row and the process returns to S 1430 . 
     In S 1450 , it is determined that the time on the n-th row is the boundary between the waveforms in S 1440 , and thus the time on the n-th row is stored in a column  930  of the ending time of the table T 4  as the ending time of the waveform. For example, in the first group  913  of the table T 3 , the time when the time interval to the next time is equal to or greater than one day “2013 Mar. 3 10:23:05” becomes the ending time, and thus the corresponding time is stored in the column  930  on the first row  923  of the table T 4 . 
     In S 1460 , the determination process whether the ending condition is satisfied is performed. That is, whether the entire data of the table T 3  are referred to in the processes of S 1410  to S 1450  until now is determined. If the entire data is referred to, the present routine is completed. Meanwhile, if the entire data of the table T 3  are not referred to, the process proceeds to S 1470 . 
     In S 1470 , in order to find out a subsequent time waveform, the counter variable n is increased by only 1, and the process returns to S 1420 . In the above, the subroutine of S 535  is completed, and subsequently the process proceeds to S 537  of  FIG. 8 . 
     In S 537 , the process of deciding a candidate of a sensor for displaying the time waveform (second graph) in S 555  is performed. According to the present embodiment, a sensor relating to two sensors (the sensors set in the vertical axis and the horizontal axis of the scatter diagram) selected at the time of creating the scatter diagram ( FIG. 11 ) in S 505  is searched from the table T 7  ( FIG. 6 ) stored in the sensor database  410 , and the sensor relating to the search result becomes a sensor candidate. Specifically, the engine pressure and the number of engine rotations which is the vertical axis and the horizontal axis of the scatter diagram in FIG.  11  are used as searching keys, a row including the engine pressure or the number of engine rotations is searched from the first column of the table T 7 , the name of the sensor stored in the second column on the corresponding row is acquired as a relating sensor. From the table T 7  illustrated in  FIG. 6 , as the sensor relating to the engine pressure and the number of engine rotations, three sensors for exhaust gas temperature, exhaust gas pressure, and coolant are acquired. Also, in addition to the three sensors, five sensors including the two sensors (the engine pressure and the number of engine rotations) used as the searching keys become candidates of the sensors for displaying the time waveform in S 555 . 
     In S 538 , among the sensor candidates decided in S 537 , a screen (second selection screen) for causing the user to select only one sensor for displaying the time waveform (second graph) is displayed on the display device  440 .  FIG. 15  is a diagram illustrating the second selection screen displayed on the display device  440  in S 538 . On the second selection screen as illustrated in  FIG. 15 , a table having a column  1230  storing names of the sensors acquired in S 537  are displayed. On the first column of the corresponding table, checkboxes  1220  are provided such that the user can input a check in a corresponding checkboxes relating to a sensor of which a time waveform is desired to be displayed. If the selection of the sensor is completed via the checkboxes  1220 , the display button  1205  is activated, and if the display button  1205  is pressed by the user, the process proceeds to S 540 . Here, as illustrated in  FIG. 15 , the description is continued assuming a case where the engine pressure is selected in S 538 . 
     In S 540 , a process of loading the sensor data selected in S 538  from the database  410  and creating a new table T 5  is performed.  FIG. 16  is a diagram illustrating a configuration of the table T 5 . According to the present embodiment, the “engine pressure” is selected in S 538 , and thus the engine pressure is loaded from the table T 1  ( FIG. 5 ) of the sensor database  410 . The data to be loaded is decided based on the table T 4  ( FIG. 13 ). Specifically, sensor data included in the time range (the ending time  930  from the starting time  920  in respective groups) regulated in the table T 4  is loaded. 
     According to the present embodiment, as illustrated in  FIG. 5 , engine pressure detected per one second is stored in the table T 1 , and thus engine pressure data per one second included in the respective time ranges regulated in the table T 4  are stored in the table T 5 . For example, first, the engine pressure data in the time range (2013 Mar. 3 10:20:43 to 2013 Mar. 3 10:23:05) relating to the first row  923  of the table T 4  is loaded from the table T 1 . The loaded sensor data  1013  is stored in the table T 5  in time series. 
     The data (integer) stored in the waveform ID of a third column  1040  of the table T 5  is identical to the ID of the group in S 535 , and applied to the respective sensor data when being stored in the table T 5 . Waveform IDs  1040  in the table T 5  are numbered to 1, 2, 3, and the like sequentially from 1. That is, a waveform ID of the sensor data  1013  in the time range relating to the first row  923  of the table T 4  is stored as 1 in the table T 5 , a waveform ID of the sensor data  1016  in the time range relating to a second row  926  of the table T 4  is stored as 2 in the table T 5 , and the waveform ID of the sensor data  1018  in the time range relating to a third row  927  is stored as 3 in the table T 5 . Hereinafter, values of the waveform IDs are increased one by one, and the sensor data are stored in the table T 5  in the same manner. The waveform ID is used in the group having a waveform similar to that in a subsequent step of S 545 . 
     In S 545 , a process of grouping time waveforms (second graph) created with the sensor data  1013 ,  1016 ,  1018 , and the like to which the same waveform ID is applied in the table T 5  according to shapes thereof is performed. The results of the groups in the time waveform are stored in the table T 6 .  FIG. 17  is a diagram illustrating a configuration of the table T 6 . In a first column  1060  of the table T 6 , waveform IDs are stored, and IDs of the waveform groups which are grouping results of the waveforms are stored in a second column  1080 . In the example of  FIG. 17 , a waveform of waveform ID=1 belongs to a waveform group ID  1000 , and the waveform IDs  2  and  3  belong to a waveform group ID  2000 . 
     Subsequently, a specific order of grouping waveforms performed in performed in S 545  is described below as a subroutine of S 545  with reference to  FIGS. 18 and 19 .  FIG. 18  is a flowchart of an internal process S 545 _SUB performed in S 545  of  FIG. 8 , and  FIG. 19  is a flowchart of a subroutine S 545 _SUB 2  (a process of grouping similar waveforms) in an internal process indicated in  FIG. 18 . 
     In S 1510  of  FIG. 18 , in order to designate the waveform ID of the table T 5 , an area of a variable X indicating a waveform ID is secured in the storage device  450 . An initial value of the variable X of the waveform ID is set to be 1 as the minimum value. 
     In S 1520 , an area of a variable G indicating the waveform group ID is secured in the storage device  450 . The variable G indicates a waveform group ID to which the waveform having the similar shape belongs. The initial value of the variable G is set to be 1000 in the present embodiment. 
     In S 1530 , a waveform ID of a third column  1040  is searched by using the value of the variable X from the table T 5  ( FIG. 16 ) as a searching key, and the sensor data of the waveform ID of X is found out. For example, if the variable X is 1, the sensor data  1013  in the waveform ID of  1  in the table T 5  becomes the sensor data to be found. 
     In S 1540 , whether a record is found out in S 1530  is determined. If one or more rows of sensor data are found from the table T 5  in S 1530 , the process proceeds to S 1550 . If sensor data are not found, it is determined that searching of all waveform IDs is completed, so as to complete the present subroutine. 
     In S 1550 , existence or non-existence of the time waveform (similar waveform) having a similar shape to the shape of the time waveform having the waveform ID of X found in S 1530  is searched from the table T 5 . In case a similar waveform exists, a process of grouping the both is performed. For example, if the variable X is 1 (that is, the waveform ID is 1), a time waveform of the sensor data  1013  and a time waveform of the sensor data (for example, the sensor data  1016  and  1018 ) relating to another waveform ID are compared with each other. In case a similar waveform exists, in the table T 6 ,  1000  (a value of the variable G) which is the same waveform group ID with respect to the waveform ID of the time waveform similar to the time waveform of the sensor data  1013  is stored. Here, a subroutine which corresponds to a grouping process and which is illustrated in  FIG. 19  is called. 
     The process content of the subroutine (S 545 _SUB 2 ) of  FIG. 19  is described. In S 1610  of  FIG. 19 , the variable G indicating the waveform group ID and the variable X indicating the waveform ID are received from the subroutine of the calling source in  FIG. 18 . If the calling is performed for the first time, the variable X is 1 and the variable G is 1000. In the steps subsequent to S 1620 , the time waveform of the engine pressure similar to the waveform having the waveform ID of X is found from the table T 5  and is stored in the table T 6  by linking to the value of the variable G. 
     In S 1620 , an area of the variable Y indicating the waveform ID of the time waveform to be compared with the time waveform having the waveform ID of X in shapes is secured in the storage device  450 . The initial value of the variable Y has the same value as the variable X. If the variable X is 1, Y also becomes 1. In the subroutine of  FIG. 19 , the value of the variable X caused to be constant, and values of the waveform ID of Y of the comparison target are increased to 1, 2, 3, and the like and are compared with the waveform ID of X, such that the similar waveforms are checked. 
     In S 1630 , the sensor data having the waveform ID of Y is searched from the table T 5 . If Y is 1, 1013 of the table T 5  is searched. In addition, since the initial value of Y is X, the waveform having the waveform ID of X is also searched, but the waveform group ID of the waveform having the waveform ID of X also needs to be stored in the table T 6  as a grouping result, and thus the corresponding process becomes a correct process. 
     In S 1640 , whether the record is found in S 1630  is determined. If the sensor data having the waveform ID of Y is found out, the process proceeds to S 1650 . If the sensor data is not found out, it is determined that all waveforms are completely compared, the present subroutine is completed, and the process proceeds to S 1560  of  FIG. 18 . 
     In S 1650 , a process of comparing a waveform having the waveform ID of X and a waveform having the waveform ID of Y with each other and determining whether the both are similar to each other is performed. According to the present embodiment, the determination whether the waveforms having the waveform IDs of X and Y are similar to each other is decided based on the size of the similarity S (X, Y) defined as below. S (X, Y) is calculated in Formula A below from Dx (k) (k=1, 2, 3, . . . , Nx) which are the sensor data of the waveform ID of X and Dy (k) (k=1, 2, 3, . . . , Ny) which are the sensor data of the waveform ID of Y. However, in Formula A below, considering the case where there is a difference between the numbers of data dots included in Dx (k) and Dy (k), m=MIN (Nx, Ny) is set. That is, among Nx and Ny which are the numbers of the sensor data dots of Dx (k) and Dy(k), one having the smaller number of data dots is set to be m. In addition, the correspondence is only an example of the correspondence of a case where there is a difference between the numbers of the data dots, and well-known correspondence such as causing the numbers of the data dots of the both to be the same by adding the data dots to the time waveform having the smaller number of data dots is possible. In addition, at the time of comparing the two waveforms, if the time ranges of the both are greatly different from each other, it is possible to determine that the both waveforms are not similar or to compare the both by scaling the waveform such that the time range of one waveform is matched with that of the other waveform. 
     
       
         
           
             
               
                 
                   
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     In the example of the table T 5  of  FIG. 16 , Dx (k) and Dy(k) are sensor values of the engine pressure. If the waveform ID of X is 1, Dx (k) is a numerical value of the engine pressure included in the sensor data  1013 , and Dx (1)=0.5628 and Dx (2)=0.5727 are satisfied. Also, if the waveform ID of Y of the comparison target is 2, Dy (k) is a numerical value of the engine pressure included in the sensor data  1016 , Dy (1)=0.5699 and Dy(2)=0.5621 are satisfied. If the similarity S (X, Y) between the waveforms having the waveform IDs of X and Y is calculated from Dx (k) and Dy (k), the process proceeds to S 1660 . 
     In S 1660 , if the similarity S (X, Y) calculated in S 1650  is greater than a threshold value S 0  decided at the time of designing the present system, it is determined that the waveforms having the waveform IDs of X and Y are similar to each other, and the process proceeds to S 1670 . Otherwise, the process proceeds to S 1680 . In addition, the threshold value S 0  may be changed afterwards. 
     In S 1670 , the IDs of the waveforms which are determined to have high similarity in S 1660  are stored in the table T 6  ( FIG. 17 ). Specifically, the value of the waveform ID of Y is stored as the waveform ID in the first column  1060  of the table T 6 , the value of the variable G is stored as the waveform group ID in the same row of the second column  1080 . The variable G is a value of the waveform group ID received from the calling source in S 1610 . For example, in case the waveform having the waveform ID of  2  and the waveform having the waveform ID of  3  in the table T 5  are similar to each other and the value of the variable G (waveform group ID) at the time of calculating the similarity between the waveforms of the both is 2000, the data is stored as in the second and third rows of the table T 6 . 
     Since the comparison between the waveforms having the waveform IDs of X and Y is completed with this, the value of the variable Y is increased by 1 in S 1680 , and comparison of a subsequent waveform is prepared. For example, if comparison between waveforms having X of  1  and Y of  1  are completed, Y is set to be 2 and comparison between the waveforms having the waveform ID of  1  and the waveform ID of  2  is prepared. Thereafter, the process returns to S 1630 . 
     With the above, the subroutine of  FIG. 19  and S 1550  of  FIG. 18  are completed, and the process proceeds to S 1560  of  FIG. 18 . 
     In S 1560  of  FIG. 18 , the variable X indicating the waveform ID of the waveform comparison source is increased by 1, and the searching of a subsequent similar waveform is prepared. For example, if the searching of the similar waveform of which the waveform ID of X is 1 is completed, the waveform ID of X is updated to 2, and the preparation for searching the subsequent similar waveform is performed. 
     In S 1570 , the variable G indicating the waveform group ID is increased by 1000, the waveform group ID to which the next similar waveform belongs to is updated, and the process returns to S 1530 . For example, if searching of the similar waveform having the waveform ID of  1  is completed, the waveform group ID of G=1000 is updated to G=2000. In addition, according to the present embodiment, if the value of the variable is increased 1000 by 1000, the increasing amount may be an arbitrary value. 
     In the above, the subroutine of  FIG. 18  and the process of S 545  of  FIG. 8  are completed, and the process proceeds to S 550 . 
     In S 550 , a screen indicating the time waveform (second graph) of the sensor data selected in S 538  ( FIG. 15 ) and the grouping result based on the table T 5  ( FIG. 16 ) and the table T 6  ( FIG. 17 ) is created.  FIG. 20  is a diagram illustrating an example of the screen which is created in S 550  and is displayed in S 555 . In the example of  FIG. 20 , a case where there are three waveform group IDs ( 1000 ,  2000 , and  3000 ) stored in the table T 6  is indicated, the inside of the screen is divided into three display portions  1100 ,  1200 , and  1300  by matching the number of the waveform group IDs. A display portion  1100  is a portion indicating waveforms belonging to the waveform group ID of  1000 , and the waveforms (second graph) having the waveform IDs of  1  and  22  belonging to the waveform group ID of  1000  in the table T 6  are displayed as the waveforms  1110  and  1120 , respectively. The sensor data for displaying the waveforms  1110  and  1120  can be searched from the table T 5  by using the waveform IDs of  1  and  22  as searching keys. 
     In addition, as the sensor data searched at the time of creating the time waveforms of the respective waveform IDs, not only the sensor data having the respective waveform IDs in the table T 5 , that is, the sensor data included in the time range defined in the table T 4 , and but also the sensor data included in the expanded time range which is obtained by expanding the corresponding time range by the time regulated before and after are added, such that the time waveform may be created. In this case, it is preferable to consider the display of the time waveform such that the time range defined in the table T 4  and the time range in an expanded amount are distinguished. Specific examples of this type of the display include changing a background of a time waveform (see a waveform  1110 A in  FIG. 21 ) and drawing dots of only the sensor data included in the time range of the table T 4  on the time waveform (see a waveform  1110 B in  FIG. 21 ). If the time of displaying the time waveform is expanded in this manner, it is possible to recognize how the sensor data are changed before and after the data selected on the scatter diagram ( FIG. 11 ) such that analysis of the data can be performed. In addition, instead of the process above, it is possible to perform the process of displaying the time waveform of the sensor data in which the time range is expanded in the sequence therebefore. 
     Detailed description is omitted, since details thereof are the same as those of the display portion  1100 , but the display portion  1200  is a portion indicating the waveforms belonging to the waveform group ID of  2000 , and three waveforms  1210 ,  1220 , and  1230  are displayed. A display portion  1300  is a portion indicating waveforms belonging to the waveform group ID of  3000 , and the two waveforms  1310  and  1320  are displayed. 
     In addition, in case waveforms relating to all waveform group IDs stored in the table T 6  cannot be displayed, waveforms of all group IDs can be caused to be displayed by forming a configuration of enabling a screen to be scrolled or to be transitioned to another screen. In addition, the screen may be formed such that only the number of waveform group IDs is displayed, the desired IDs are selected by clicking the IDs with a mouse or the like, and all waveforms belonging to the corresponding ID are displayed. That is, if the total number of the waveform group IDs (the number of groups) included in the table T 6  and the shapes of the waveforms included in the respective groups can be checked, a method of displaying the respective waveforms is not particularly limited. 
     If the process of creating the screen is completed, the process proceeds to S 555 . In S 555 ,  FIG. 20  created in S 550  is displayed on the display device  440  so as to be provided to the user. Accordingly, a series of processes illustrated in  FIG. 8  is completed. In addition, incase a scatter diagram of other sensor data is desired to be displayed, the process returns to the initial S 505 . In case time waveforms of other sensor data are desired to be displayed though the selection of data dots on a scatter diagram is not changed, the process may return to S 538 . 
     According to the data display system configured as described above, if an item of which a temporal change around a portion of the generation time for a set of data relating to a certain item is desired to be known is designated, an aspect of the temporal change around the generation time of the data relating to the designated item can be easily recognized. Accordingly, for example, even in a case where an outlier is generated for a short period of time of several seconds to several hours, a time waveform graph for a short period of time around the generation time is displayed, such that a main cause of the outlier can be analyzed from the waveform when the outlier is generated. 
     In addition, the sequence of the respective processes used in  FIGS. 8, 14, 18, 19 , or the like is merely an example, and can be appropriately changed as long as the sequence is in the range in which the effect above can be exhibited. 
     In addition, in the above, a case where screens are transitioned in the sequence of  FIGS. 9, 11, 15, and 20  is described, but in case a sensor that has to display a scatter diagram and a time waveform is designated in advance,  FIGS. 9 and 15  can be omitted. In addition, in  FIG. 11 , after the data is selected in the cursor  705 , a short cut operation which is designated in advance is performed with the input device  425  such as a mouse, a keyboard, and a touch panel, the selection of the sensor as illustrated in  FIG. 15  is alternately performed, and the display of  FIG. 15  can be omitted. 
     In addition, the scatter diagram is displayed as  FIG. 11  in the above. However, another graph may be displayed as long as the graph is a graph for recognizing the tendency of the sensor data in the database  410 , such as a histogram or a pareto graph. At this point, it is obvious that the screen of  FIG. 9  is created such that a necessary index can be appropriately input required for regulating the graph displayed in  FIG. 11 . 
     In addition, in the above, an occasion in which a so-called outlier on  FIG. 11  is selected, a trend of the outlier is recognized from a time waveform, and a cause of a disorder is investigated is described as an example. However, the invention is not limited thereto, and the invention is widely useful in an occasion in which, in case plural partial sets are recognized with respect to the distribution of data relating to a certain item, a change of certain data relating to the time at which the data included in the respective partial sets are detected is displayed, and the tendency of the data included in the partial set is visually recognized. 
     With respect to functions corresponding to the present system illustrated in  FIG. 7 , execution processes for exhibiting the corresponding functions, and the like, a portion or all of the functions and the execution processes may be realized by hardware (for example, designing logics for executing the respective functions with an integrated circuit). In addition, the configuration relating to the data display system may be a program (software) by which respective functions relating to the configuration of the corresponding system is realized by being read and executed by a processing device (for example, a CPU) are realized. For example, the information relating to the program may be stored in a semiconductor memory (a flash memory, an SSD, or the like), a magnetic storage device (a hard disk drive or the like), a storage medium (a magnetic disk, an optical disk, or the like), or the like. 
     In addition, in the description of the embodiment, control lines or information lines which are considered to be necessary in the description of the embodiment is provided. However, it is not considered that all control lines and all information lines which relate to the product are necessarily described. In reality, it may be considered that almost all configurations are connected to each other. 
     In addition, the invention is not limited to the embodiment described above, but various modification examples are included without departing from the gist of the invention. For example, the invention is not limited to include all configurations described in the embodiment described above, but includes an example in which a portion of the configurations is deleted. 
     REFERENCE SIGNS LIST 
     
         
         
           
               410  . . . sensor database,  415  . . . occurrence frequency information creating portion,  420  . . . time waveform data creating portion,  425  . . . input device,  430  . . . data aggregating portion,  435  . . . similar waveform searching portion,  440  . . . display device,  445  . . . processing device,  450  . . . storage device, S . . . similarity