Abstract:
The cost necessary for introducing and maintaining a development environment that includes multiple simulators is suppressed, and a sharing of designing information is promoted, to make parameter adjustment of simulators easy. Provided is a service that unifies development environment on a computer provided with: a working computer system that can guarantee that there is no leaking of designing files; a user behavior monitoring system that collects utilization history of simulators or software, for each of the users, and selects development process of each of the users from the collected information; and a dynamic computational-resource distribution system that can conduct an automatic optimization of a complex simulation configuration, from information collected by the aforementioned user behavior monitoring system.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a technology used in a development environment, in which a plurality of simulators execute a coordinated complicated simulation in the development of an embedded system. 
     An embedded system is a system composed of a mechanism constituting a control object, hardware for performing a control operation based on a physical quantity received from the mechanism and outputting a control value to the mechanism, and software which operates on the hardware. For example, an embedded system of an automotive vehicle is composed of an engine as a control object, an electronic device such as a microcomputer for controlling the engine, and software which operates on the microcomputer. Since the behavior of the software included in the embedded system strongly depends on the mechanism of the control object and the configuration of the hardware, it is necessary to analyze combined behavior of the mechanism, the hardware and the software. 
     In recent years, embedded systems have become more complicated to make automotive vehicles, electrical apparatuses and the like more reliable and more functional. Accordingly, to shorten a working period, parts of hardware and software are fragmented and specialized and development is simultaneously carried out at a plurality of sites. As fragmentation progresses, deficiency in performance and defect in specification which are ascertained when the parts are assembled are on the increase in addition to checking of the operation of each part. Thus, a delay in development period caused by a rework at a final stage before product shipment frequently occurs, thereby causing a problem of deteriorating development efficiency. 
     To solve this problem, it has been started to use a performance evaluation and verification technique by a simulation in which the mechanism, the hardware and the software are collaborated at the time of designing. In a mechanism/hardware/software collaborated simulation, a collaborative simulation at the overall product level is executed by mutually connecting different types of simulators since usable simulators differ depending on the configurations of the mechanism and the hardware to be simulated and simulation models created for specific simulators are already accumulated. 
     Conventionally, to execute a collaborative simulation in which a plurality of simulators are mutually connected, it is necessary to build an execution environment on a computer of each individual. For this, the following five problems exist. The first problem is that it is difficult to share design files and manage progresses due to the simultaneous development at a plurality of sites. The second problem is that cost for manually adjusting the simulators and connection parameters among the simulators increase since different simulators need to be connected. 
     The third problem is that cost for introduction and maintenance is high since a plurality of simulators are used. The fourth problem is that computational capability becomes insufficient since a plurality of simulators are operated. The fifth problem is a high risk of information leakage since design files are stored in each individual PC. 
     As one way of coping with the above problems, it is thought to unify development environments. As a known technology on unification of development environments, a computational environment providing service is disclosed in patent literature 1. In this service, a server on a network is rent to a user and the user obtains a computational environment by remotely controlling the server. 
     CITATION LIST 
     
         
         Patent literature 1: JP2002-24192A 
       
    
     SUMMARY OF THE INVENTION 
     The technology of the above patent literature 1 can solve the fourth and fifth ones of the above problems, but cannot solve the other problems and service users need to individually deal with them. Problems the present invention seeks to solve are the first to third ones of the problems descried in the above background art. 
     As described above, the first problem is that it is difficult to share design files and manage progresses due to the simultaneous development at a plurality of sites. Further, the second problem is that cost for manually adjusting the individual simulators and connection parameters among the simulators increases since different simulators need to be connected. Furthermore, the third problem is that cost for introduction and maintenance of the hardware and the software is high and it is difficult to easily execute a simulation since a plurality of simulators and computational resources are necessary. 
     The present invention has been developed in view of the above problems and an object is to suppress cost required for introduction and maintenance of a development environment including a plurality of simulators, share design information and facilitate adjustment of parameters of the simulators. 
     An aspect of the present invention solves the first problem by including a mechanism for selecting and recording a simulator or software usage history of each user with high accuracy in embedded system development and another mechanism for selecting a development process of the user from information collected by the former mechanism and recording it. 
     Further, the second problem is solved by including a mechanism for automatically optimizing a simulation configuration from the information collected by the former mechanism. 
     Furthermore, the third problem is solved by enabling a reduction in initial investment for environment and facilities by a service which realizes unification of development environments on a computer including the above mechanisms. 
     Accordingly, since an aspect of the present invention allows simulators or software to be all managed on a server system, embedded system developers need not purchase them in advance and maintain them. Further, since developed software and simulation results using the software are managed on the server system, it becomes easier to share design files and a risk of leaking information to outsiders can be suppressed to a minimum level. 
     Further, since the developers can easily execute quick and accurate simulations without requiring detailed know-how due to the cooperation of a plurality of simulators and automated adjustment of simulator parameters, development efficiency of the embedded system is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a first embodiment of the present invention and functional elements of a computer system, 
         FIG. 2  is a flow chart showing the first embodiment of the present invention and an example of a process performed in a user terminal, 
         FIG. 3  is a block diagram showing the first embodiment of the present invention and the detailed configuration of the entire system, 
         FIG. 4  is a flow chart showing the first embodiment of the present invention and an example of a process in a software development mode, 
         FIG. 5  is a flow chart showing the first embodiment of the present invention and an example of a process in a simulation mode, 
         FIG. 6  is a flow chart showing the first embodiment of the present invention and an example of a process in a development progress/tool usage status/system usage fee confirmation mode, 
         FIG. 7  is a diagram showing the first embodiment of the present invention and an example of a screen image of a simulation task input device, 
         FIG. 8  is a diagram showing the first embodiment of the present invention and an example of a screen image in the case of reusing the configuration of a task created in the simulation task input device, 
         FIG. 9  is a diagram showing the first embodiment of the present invention and an example of a screen image when an abstraction level of a task input decreases in the simulation task input device, 
         FIG. 10  is a diagram showing the first embodiment of the present invention and an example of a screen image presenting a simulation task configuration created by the task input device, 
         FIG. 11  is a diagram showing the first embodiment of the present invention and a task configuration result, 
         FIG. 12  is a flow chart showing the first embodiment of the present invention and task creation by a simulation task creating device, 
         FIG. 13  is a diagram showing the first embodiment of the present invention and a configuration example of a cluster node constituting simulation computational resources, 
         FIG. 14  is a block diagram showing the first embodiment of the present invention and an example of the simulation computational resources, 
         FIG. 15A  is a flow chart showing the first embodiment of the present invention and an example of a process of calculating a system usage fee, 
         FIG. 15B  is a flow chart showing the first embodiment of the present invention and an example of a process of calculating a license fee, 
         FIG. 16A  is a flow chart showing the first embodiment of the present invention and an example of a process of analyzing a development progress, 
         FIG. 16B  is a flow chart showing the first embodiment of the present invention and an example of a process of analyzing a tool usage status, 
         FIG. 17  is a diagram showing the first embodiment of the present invention and a table configuration example of a resource usage management database and a resource price database, 
         FIG. 18  is a diagram showing the first embodiment of the present invention and a table configuration example of an operation history database, 
         FIG. 19  is a diagram showing the first embodiment of the present invention and a table configuration example of a tool/model database, 
         FIG. 20  is a diagram showing the first embodiment of the present invention and a table configuration example of the resource price database, 
         FIG. 21  is a diagram showing the first embodiment of the present invention and an example of an information flow graph of a graph structure that a task given from a user by analyzing a temporal sequence and the flow of operations is a base point, simulation trials and file changes are points and a dependency relationship of information is an edge, 
         FIG. 22  is a diagram showing the first embodiment of the present invention and an example of a development progress report, 
         FIG. 23  is a diagram showing the first embodiment of the present invention and an example of a command list, 
         FIG. 24  is a diagram showing the first embodiment of the present invention and an example of a database for managing a state of the simulation computational resources, 
         FIG. 25  is a diagram showing the first embodiment of the present invention and an example of a tool usage status report, 
         FIG. 26A  is a diagram showing the first embodiment of the present invention and an example of a simulation configuration table of a simulation configuration history database, 
         FIG. 26B  is a diagram showing the first embodiment of the present invention and an example of a simulation configuration table of the simulation configuration history database, 
         FIG. 27  is a diagram showing the first embodiment of the present invention and an example of a system usage fee report for a user, 
         FIG. 28  is a diagram showing the first embodiment of the present invention and an example of a license fee report for a software provider, and 
         FIG. 29  is a block diagram showing a second embodiment of the present invention and functional elements of a computer system. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     First Embodiment 
     Hereinafter, one embodiment of the present invention is described based on the accompanying drawings.  FIG. 1  is a functional block diagram schematically showing one example of the embodiment of the present invention and a computer system (development assisting system for embedded devices) for assisting the development of an embedded system. 
     In a computer system used to develop an embedded system, a dynamic computational resource distribution system  100 , simulation computational resources  101 , a simulation result visualization system  102 , a system load/user behavior monitoring system  103 , a work computer system  106 , a screen data transmission system  104  using secure communication, a user terminal  107  and a software provider terminal  108  are connected via an internal network. 
     The above configuration is called the present system below. The user terminal  107  and the software provider terminal  108  can access the present system only via the screen data transmission system  104  using secure communication. Note that each of the systems, computational resources and terminals are constructed by a computer including a processor, a memory and an interface. 
     Further, the embedded system is a combination of a mechanism as a control object, hardware for driving the mechanism and software for controlling the hardware. 
     A summary of the present system is that embedded software is created in the work computer system  106  in accordance with an input or command from the user terminal  107  and a simulation of the created embedded software is optimized in the dynamic computational resource distribution system  100 . 
     The dynamic computational resource distribution system  100  executes an optimized simulation task in the simulation computational resources  101  including a plurality of computers. The simulation computational resources  101  includes simulation software (simulators) for executing a simulation, a computer (cluster node  1400  in  FIG. 14 ) for executing a simulation, a plurality of applications for executing a plurality of types of simulations, and a plurality of computers for executing the applications. 
     When a simulation of the embedded software is executed, the user terminal  107  instructs the dynamic computational resource distribution system  100  to execute the simulation. The dynamic computational resource distribution system  100  secures software resources and hardware resources of the simulation computational resources  101  and executes the simulation based on a request from the user terminal  107 . 
     The screen data transmission system  104  functions as a gateway for transmitting and receiving data to and from the user terminal  107  or the software provider terminal  108 , authenticates the user terminal  107  (or the software provider terminal  108 ), and transmits and receives data to and from the user terminal  107  (or the software provider terminal  108 ) by highly confidential communication (hereinafter, secure communication) such as encrypted communication. 
     The present system also includes the simulation result visualization system  102 . The simulation result visualization system  102  includes a computer for providing a simulation result calculated by the simulation computational resources  101  such as in the form of a graph to the user terminal  107 . 
     The present system also includes the system load/user behavior monitoring system  103 . The system load/user behavior monitoring system  103  includes a computer for collecting hardware and software operational statuses of the simulation computational resources  101 , a computer for collecting a progress status of the embedded system developed in response to an input or a command from the user terminal  107  or the like and generates billing information and statistical information for each user terminal  107 . Note that each of the computer systems is described in detail later. 
       FIG. 2  is a flow chart of a development work of the embedded system performed in the user terminal  107  in the present system. An operation when a user utilizes the present system according to this embodiment using the user terminal  107  is described with reference to  FIGS. 1 and 2 . 
     First in Step  301 , the user connects the user terminal  107  with the screen data transmission system  104 . The screen data transmission system  104  authenticates whether or not the user terminal  107  possesses access authority to the present system. The software provider terminal  108  is similarly connected to the screen data transmission system  104 , and the screen data transmission system  104  authenticates whether or not the software provider terminal  108  possesses access authority to the present system. 
     Since the user or the software provider certainly accesses via the screen data transmission system  104  after authentication, the description on the access via the screen data transmission system  104  is omitted below. 
     Subsequently, in Step  302 , the user selects an operation content using the user terminal  107 . The present system includes three operation content modes, which are a software creation mode  315  for creating the embedded software, a simulation mode  316  for executing a simulation to control the mechanism as the control object by the created embedded software and a development progress/tool usage status/system usage fee confirmation mode  317  for obtaining a usage status of the computational resources of the present system. In the above three modes, contents of services to be provided differ and, in addition, methods for calculating a system usage fee differ. 
     Further, the screen data transmission system  104  requests selection of any one of the above three modes to the user terminal  107  after authentication of the user terminal  107  is completed. When the user terminal  107  notifies a selection result to the screen data transmission system  104 , the screen data transmission system  104  notifies the start of usage from the user terminal  107  to the computer system corresponding to the selected mode. The computer system (dynamic computational resource distribution system  100 , the work computer system  106  or the system load/user behavior monitoring system  103 ) notified of the start of usage from the screen data transmission system  104  starts providing a service to the user terminal  107 . 
     First, a work flow when the user selects the software creation mode  315  from the user terminal  107  is described. The user terminal  107  develops software for the embedded system by remotely operating the work computer system  106  in Step  304  and stores a created design file in Step  305 . The user terminal  107  stores the design file in a storage device in the work computer system  106  or the present system. 
     Next, a work flow when the user selects the simulation mode  316  from the user terminal  107  is described. In the case of selecting the simulation mode, the dynamic computational resource distribution system  100 , the simulation computational resources  101  and the simulation result visualization system  102  executes a simulation instructed by the user terminal  107  in response to a command from the user terminal  107 . 
     First, in Step  307 , the user inputs a simulation configuration (dependency relationship of a plurality of simulation tasks) using a plurality of commercial simulation software (or simulators) to the dynamic computational resource distribution system  100  from the user terminal  107 . 
     In next Step  308 , the dynamic computational resource distribution system  100  secures the simulators, the simulation result visualization system  102 , and CPUs, a memory capacity, special computing units (accelerators) and a storage area in the simulation computational resources  101  sufficient to perform a simulation task received from the user terminal  107 . The dynamic computational resource distribution system  100  calculates an arrangement relationship of the simulators on the simulation computational resources  101  and constructs an actual simulation task so that the simulation task configuration is optimally executed based on a coupling relationship of the parts (mechanism to be developed, hardware, software) in the simulation task input from the user terminal  107 . 
     Note that the simulation task, the simulation configuration and the simulation task configuration are defined as below in the following description. 
     The simulation task indicates a simulation object in which the elements of the mechanism, the hardware and the software in the embedded system are coupled. A plurality of simulations can be included in a simulation task. 
     The simulation configuration defines a dependency relationship among the simulations when simulations are included in a simulation task. 
     The simulation task configuration defines a relationship between the cluster nodes  1400  of the simulation computational resources  101  and simulations to be allocated to the cluster nodes  1400 . The simulation task configuration is, for example, expressed by a command list as shown in  FIG. 23 . 
     A task creation result, for example, in the case of developing a control system for an internal combustion engine as an embedded system is shown in  FIG. 11 . If a simulation of an engine control ECU (Electronic Control Unit) is a simulation task, simulation elements (parts) are the engine control ECU, an air flow meter, an injector and an engine. Then, a plurality of simulation software programs (simulators) respectively corresponding to the engine control ECU, the air flow meter, the injector and the engine are executed. The cluster nodes  1400  that execute the respective simulators are allocated by the simulation task configuration. 
     The dependency relationship (simulation configuration) of the simulators is as described below in the example of  FIG. 11 . Data such as an intake air amount of the air flow meter are input to the simulator of the engine control ECU. A fuel injection amount and the like from the engine control ECU are input to the simulator of the injector. A fuel injection period and a fuel injection amount from the injector are input to the simulator of the engine. The rotational speed and the like of the engine are input to the simulator of the air flow meter. Further, an engine output is input to a simulator (Loger001.exe of  FIG. 11 ) of the entire system. That is, an input/output relationship of data among simulation software programs is the simulation configuration. 
     Thereafter, the simulation is executed in Step  309 . Specifically, if the user instructs to execute the simulation task configuration constructed in the dynamic computational resource distribution system  100  from the user terminal  107 , the dynamic computational resource distribution system  100  inputs the simulation task to the simulation computational resources  101 . The cluster node  1400  having the simulation task allocated thereto executes the simulation in the simulation computational resources  101 . 
     Subsequently, a simulation result is displayed in Step  310 . Specifically, the simulation result visualization system  102  analyzes the simulation task configuration input from the user terminal  107  and estimates a simulation result required by the user. The simulation result visualization system  102  further allocates the simulation result meeting the user&#39;s request to a simulation result visualization unit  715  in inside. The simulation result visualization unit  715  is an independent program included in the simulation result visualization system  102  and graphs one or more specific types of data by a specific method. There are a multitude of mounting forms depending on a graphing method and the type of data to be received. 
     The result of the simulation executed in the simulation computational resources  101  is transmitted to the simulation result visualization system  102 . As described above, the simulation result is processed into a form desired by the user and presented to the user terminal  107  via the screen data transmission system  104  using the secure communication. 
     Next, an operation of collecting and recording information performed in the background of the present system during the execution of the above software creation mode  315  and simulation mode  316  is described. 
     Information is collected, recorded and its statistics is taken by the system load/user behavior monitoring system  103 . This enables data collected in the development progress/tool usage status/system usage fee confirmation mode  317  described below to be provided to the user. 
     The system load/user behavior monitoring system  103  monitors and records a GUI operation and a file operation of the user terminal  107  in the work computer system  106  using the secure communication, the input of a simulation from the user terminal  107  in the dynamic computational resource distribution system  100  and system loads on CPUs, memories, network and storages in the simulation computational resources  101 . 
     The system load/user behavior monitoring system  103  performs several processes using the obtained recorded GUI operation and file operation of the user terminal  107 , a simulation instructed from the user terminal  107  and a system history data. These processes include calculation of a usage fee for the user terminal  107 , creation of a development progress report of the user terminal  107  or a group to which the user belongs, calculation of a license fee payment amount for the software provider providing the simulators introduced into the simulation computational resources  101 , and creation of a usage status report of the simulators introduced into the simulation computational resources  101 . 
     A work flow when the above development progress/tool usage status/system usage fee confirmation mode  317  is selected is described with reference to  FIG. 2 . The present system performs this work using the system load/user behavior monitoring system  103 . 
     In Step  313 , the user terminal  107  selects the type of information desired to be browsed out of the development progress report, the software usage status report and the system usage fee report. In Step  314 , the user terminal  107  browses the selected information via the screen data transmission system  104 . 
     If the user is developing the embedded system or the like on the present system by operating the user terminal  107 , the user receives the usage fee information and the development progress report of the present system calculated by the system load/user behavior monitoring system  103 . 
     If the user is a software provider and provides software to the present system, the user can receive the software usage status and a report on license revenue from the usage of the software which are calculated by the system load/user behavior monitoring system  103 . 
     Next, the present system is described in detail.  FIG. 3  is a block diagram showing a detailed construction of devices necessary to execute the present system. A connection relationship of the devices in  FIG. 3  merely shows an example of an embodiment and a widely or publicly known technology may be used if the functions described above can be obtained. 
     Confirmation of information for user connection (authentication) described in Step  301  of  FIG. 2  is executed by a user connection authority confirming device  702  in the screen data transmission system  104  shown in  FIG. 3 . An authentication method using the exchange of files including encrypted individual identification information, an authentication method using a device including individual identification information encrypted at a user side and the like as well as a method using an ID number and a password for identifying a user (user terminal  107 ) can be used as an authentication method provided in the user connection authority confirming device  702 . 
     Further, a method for providing a login program as an application on a web browser, a method for providing a login program as an independent application which operates on a user&#39;s personal computer (user terminal  107 ) and a method for introducing and providing an OS (Operating System), which is configured such that only a login program to the present system operates, to the above device including the individual identification information are thought as a method for providing a login program to the present system. However, in the present invention, a widely or publicly known technology may be used if it meets a requirement that communication confidentiality between the user and the present system is ensured and it is impossible for a person who is not authorized to use the present system to log into the present system. 
       FIG. 4  shows a process flow of the present system in the software creation mode  315 . Using  FIGS. 4 and 3 , the process of the present system in the software creation mode  315  is described in detail. The software mentioned here indicates the software of the embedded system to be developed by the user, simulation models necessary in executing a simulation, and the simulation result visualization system  102 . 
     In Step  401 , the user terminal  107  selects the software creation mode. In Step  402 , the work computer system  106  allocates a work environment suitable for the user using the user terminal  107 . By this allocation, the user terminal  107  can use a tool/model database  709  and the like of the dynamic computational resource distribution system  100  via the work computer system  106 . The work computer system  106  is composed of work computational resources  722 , a user file storage  707  and a work environment providing device  703  to be described later. 
     In Step  304 , the user develops the software by remotely operating the above allocated work environment from the user terminal  107 . In Step  305 , a design file and the like created by the user are stored in the user file storage  707 . A change made to the user file storage  707  by the user at this time is registered as a file access history in an operation history database  708  for recording a GUI operation and a file history by a file history recording device  714  in Step  404 . 
     In Step  403 , the GUI operation of the user in the user terminal  107  in the work environment provided by the work computer system  106  is obtained by a user behavior statistics device  713  to be described later and registered in the operation history database  708 . The registered GUI operation history is used to visualize the development progress and used as statistical information of the software usage status. 
     When the user of the user terminal  107  finishes the development of the software and selects the termination of the work environment in Step  306 , the user behavior statistics device  713  obtains a difference between login time to the work environment and logout time therefrom as a usage time using the function of the OS of the user terminal  107 . The obtained usage time is registered in a resource usage management database  711  for recording the system loads in the present system and used to calculate the usage fee of the software creation mode  315  in Step  405 . 
     The user file storage  707  of the work computer system  106  is a file storage area arranged on the network and design files created in the software creation mode  315  and simulation log files in the simulation mode  316  are stored therein. 
     The user file storage  707  is divided into small areas allocated to each user or each group to which the user belongs. Note that the user file storage  707  is classified according to transfer performance and capacity, and a storage usage unit price used at the time of calculating the system usage fee also differs depending on the class. 
     A used amount or allocated amount is registered in the resource usage management database  711  in advance for each small area (e.g. block) by the function of a storage system constructing the user file storage  707  and used in calculating the system usage fee for the user. 
     An administrator of the present system maintains the confidentiality of the present system by setting access authorities of the users to read from, write in and refer to an arbitrary small area in advance. 
     The work computational resources  722  are configured to include a computer in which one or more OSs (Operating Systems) operate. The work computational resources  722  are in a state where the software provided to the present system is usable. For the types of the OSs used to construct the work environment, a widely or publicly known technology may be used. Typically, a plurality of types of OSs are used to enable the operation of all the software provided to the present system. 
     Further, since the simulator or software used by the user terminal  107  differs, the setting of the OSs provided to the user terminal  107  is typically widely ranging. 
     With a normal configuration to provide one OS for one computer, the number of computers required to meet the above request increases. However, by using visualization software enabling a plurality of OSs to operate on one computer such as VMWare, the number of computers necessary for the work computational resources provided by the work computer system  106  can be reduced. 
     Further, the work computational resources  722  requires a function of obtaining the login time of the user terminal  107 , the logout time of the user, the number of usage, usage time and used functions for each type of software used by the user. To realize a function of obtaining these pieces of information, a case where the functions provided by the OSs are used and a case where introduction of software complementing functions not provided by the OSs is necessary are thought. A widely or publicly known technology may be used to realize the functions. 
     The work environment providing device  703  is a computer which selects an optimal OS configuration from the work computational resources  722  based on the type of the OS meeting the request of the user operating the user terminal  107  and the type of the software used, couples it with the corresponding user area in the user file storage  707  and provides the resultant to the user. 
     Two methods can be adopted as a method for realizing the coupling of the work computational resources  722  and the user file storage  707 . According to one method, after one or more dedicated work environments are allocated to all the users from the work computational resources  722 , changes made to the work environments by the users during the works other than products stored in the user file storage  707  are also stored in the work environments so as to be reusable in the future usage. 
     According to the other method, when all the users use the same work environment, changes made to the work environment by the users other than products stored in the user file storage  707  are discarded. In the present invention, a widely or publicly known technology may be used for the method for providing a work environment except in that products are registered in the user file storage  707 . 
     At least two methods are possibly adopted as a method for connecting the user file storage  707  and the work environment. According to one method, the user file storage  707  is mounted as a disk area in which only the user can write on the OS constructing the work environment. According to the other method, the user file storage  707  is not mounted on the OS constructing the work environment and the user is let to actively copy the design file in the user file storage  707 . 
       FIG. 5  shows a process flow of the present system in the simulation mode  316 . Using  FIGS. 5 ,  2  and  3 , operations in the simulation mode  316  are described in detail. 
     When the user terminal  107  selects the simulation mode  316 , a simulation is executed by the dynamic computational resource distribution system  100 , the simulation computational resources  101  and the simulation result visualization system  102 . 
     The dynamic computational resource distribution system  100  is composed of a simulation task input device  704 , a simulation task creating device  705  and a simulation task issuing device  723 . Note that although these devices are independent computers in  FIG. 3 , a program for realizing functions of these devices may be executed in one computer. 
     The simulation result visualization system  102  is configured to include the simulation result visualization unit  715  allocated by the simulation task creating device  705 , and the simulation result visualization unit  715  is connected to a screen data transmitting device  701  of the screen data transmission system  104 . 
     In Step  307  of  FIG. 2 , the user terminal  107  creates a simulation configuration desired by the user using the simulation task input device  704 . 
     When construction of a simulation object using the simulation task input device  704  is finished, a control of  FIG. 5  is started. In Step  501 , the simulation task creating device  705  of the dynamic computational resource distribution system  100  estimates computational resources necessary to execute the simulation configuration received from the user terminal  107 . 
     Thereafter, in Step  308 , the dynamic computational resource distribution system  100  presents necessary time and cost calculated by the simulation task creating device  705  and the simulation configuration allocated to the computational resources (cluster node  1400  of  FIGS. 13 ,  14 ) to the user terminal  107 . 
     The user using the user terminal  107  returns to Step  307 , adjusts parameters in the simulation task input device  704  and requests an estimate to the simulation task creating device  705  again if information presented from the dynamic computational resource distribution system  100  falls short of his desire. 
     On the other hand, if the time and cost necessary to execute the simulation and presented to the user terminal  107  by the simulation task creating device  705  meet the user&#39;s desire, the user instructs the simulation task issuing device  723  to execute the created simulation task from the user terminal  107  in next Step  309 . 
     When the user terminal  107  instructs the simulation task issuing device  723  to execute the simulation task, the simulation task issuing device  723  secures a necessary number of CPUs and a minimum number of cluster nodes to satisfy a memory amount out of the simulation computational resources  101  in accordance with a command list  1202  generated as the simulation task configuration and illustrated in  FIG. 23  in Step  503 . 
     Licenses of all the software necessary for the simulation configuration input from the user terminal  107  are secured by a license server  724  to be described later and the simulation is started. 
     In Step  504 , the simulators executed by the cluster nodes  1400  of the simulation computational resources  101  shown in  FIGS. 13 ,  14  proceed with the simulation while exchanging data with each other. 
     At that time, the simulation result visualization unit  715  of the simulation result visualization system  102  accumulates data received from one or more simulators (cluster nodes  1400 ) and processes the accumulated data to obtain a graph designated from the user terminal  107  in Step  310 . 
     If it is designated to present data processed by the simulation result visualization unit  715  in real time to the user terminal  107 , the simulation result visualization unit  715  provides the user terminal  107  with data visualizing the simulation (graph or the like) via the screen data transmission system  104 . 
     If real-time presentation is not designated, the simulation result visualization unit  715  retains the processed data in the user file storage  707 . In response to a request from the user terminal  107 , the simulation result visualization unit  715  provides the visualized data from the user file storage  707 . 
     A load on the present system during the execution of the simulation is recorded in the system load/user behavior monitoring system  103  by the following process. 
     Loads on the CPU and the memory of the cluster node  1400  to which the simulation task configuration is allocated are measured in the simulation computational resources  101  in Step  506  shown in  FIG. 5 , and a simulation log is recorded in Step  505 . Data are recorded as a resource usage amount in the resource usage management database  711  of the system load/user behavior monitoring system  103  shown in  FIG. 3 . 
     The system load during the execution of the simulation stored in the resource usage management database  711  is analyzed together with behavior information of the user terminal  107  after the execution of the simulation stored in the operation history database  708 . An analysis result is fed back to a task creation algorithm of the simulation task creating device  705  to improve accuracy in creating the simulation task configuration. 
     Two methods are possibly adopted as a method for presenting the simulation mode  316  to the user. According to one method, similar to the software creation mode, the task input device  704  and the simulation result visualization unit  715  out of the simulation computational resources  101  are respectively mounted as independent applications and a work environment for simulation execution is allocated. 
     According to the other method, the task input device  704  and the simulation result visualization unit  715  are presented as applications on a web browser. In the present invention, any widely or publicly known technology may be used for the method for presenting the task input device  704  and the simulation result visualization unit  715  to the user. 
     The license server  724  of the dynamic computational resource distribution system  100  is a computer holding a license key necessary to start the software introduced to the simulation computational resources  101 . 
     Normally, the start of commercial software is limited by license authentication to prevent illegal copying. Two methods can be adopted as a method for limiting the start of software by license authentication. According to one method, authentication is performed in each computer using information specific to the computer, for example, an individual identifier of a network interface or that of a hard disk. According to the other method, authentication is performed by one computer and the other computers obtain a license from the authenticated computer. 
     In this embodiment, the method using the license authentication by the license server  724  is described. However, a widely or publicly known technology may be used for the method for providing authentication in the present invention. Generally, in an environment which includes simulation computational resources composed of a multitude of computers and in which software to be executed is dynamically changed as in this embodiment, the former authentication for each computer increases cost to administrate the computers since the number of necessary licenses increases. 
       FIG. 7  shows an example of a typical configuration of the simulation task input device  704  of the dynamic computational resource distribution system  100 . The simulation task input device  704  is mounted as a computer for executing a GUI application with a task configuration display region  801  and a tool palette  802 . 
     The tool palette  802  includes all simulation models usable for simulation configuration as a plurality of part blocks  804  and each part block  804  is composed of one simulation model or a collection of simulation models. Assuming that a multitude of simulation models are registered in the tool palette  802 , the simulation models may be so mounted as to be displayed in a divided manner according to the type thereof in menu  806 . 
     In an embodiment of  FIG. 7 , classification by fields of application such as automobile, aviation, OA and hydraulic machine, classification by physical layers of simulation objects such as electronic and environmental model or classification by simulators for executing simulation models to be described later are presented. In  FIG. 7 , the field of automobile is selected from the menu  806 , and simulation models of mechanical parts in an embedded system of an automotive vehicle such as an engine and a motor, driving parts such as an injector and a sensor and electronic parts such as a controller are displayed. 
     The user can arrange the part blocks  804  selected from the tool palette  802  on the task configuration display region  801  and describe an inter-part connection relationship among part blocks  820  to  825  arranged on the task configuration display region  801  using arrow lines  815 . At this time, the user need not expressly designate by which software each of the part blocks  820  to  825  is executed and to how many I/O interfaces they are connected. Further, the user can cause a parameter setting display region  805  to be displayed for each of the part blocks  820  to  825  arranged on the task configuration display region  801  using the user terminal  107 . 
     The parameter setting display region  805  displays standard operation parameters of the parts  820  to  825  at first, and the user can appropriately change the operation parameters in conformity with the simulation configuration using the user terminal  107 . Examples of the operation parameters of the models include a step cycle  817  for updating an event, an abstraction level  807 , internal data  808  desired to be visualized by the user, and the like. 
     The simulation result visualization unit  715  for visualizing data is allocated to the simulation environment by being inserted into the part, the internal state of which is desired to be monitored, or connection between the parts on the task configuration display region  801 . Further, which presentation method is used at that time can be abstractly selected. 
     In this embodiment, the user designates allocation of a continuous type graph visualization unit  811  for visualization of the engine block  825  and allocation of a discrete type graph visualization unit  821  for visualization of the internal state of the engine control ECU  820  as shown in  FIG. 7 . 
     On a setting display region  814  for parameters relating to the overall simulation configuration, the user sets parameters used by the simulation task creating device  705  at the time of creating a simulation task to be described later. 
     In this embodiment, the user designates a target end time  816  of the simulation configuration designated from the user terminal  107 . Two methods, i.e. a method for designating a time at which the simulation is desired to be finished as in  FIG. 7  and a method for designating the elapse of time can be supposed as a method for setting the target end time  813 . In the present invention, a widely or publicly known technology may be used for this designation method. As just described, the task configuration display region  801  is a GUI for setting and displaying according to an input from the user terminal  107 . 
     In  FIG. 7 , the simulation configuration input from the user terminal  107  by the user can be saved. Specifically, the user can save the simulation configuration on the task configuration display region  801  in a simulation configuration history database  721  by pressing a save button  813  on the task configuration display region  801 . In saving the simulation configuration, the user can set a disclosure range of the saved simulation configuration, the presence or absence of authority for detailed reference/change of the configuration and ON/OFF of edit items of parameters of the individual part blocks using the user terminal  107 . 
     Hereinafter, the above saved simulation configuration is called a subsystem.  FIG. 8  shows a screen presentation example when the subsystem saved in  FIG. 7  is reused. By using the subsystem, a created simulation configuration  900  can be reused while being shared by other users. 
     The simulation configuration  900  saved in the simulation configuration history database  721  by the user is displayed on a user definition menu  906  of the tool palette. If this simulation configuration  900  is arranged on the task configuration display region  801 , the simulation environment constructed in  FIG. 7  is developed as in  FIG. 8  and parameters set by the user who created the subsystem are displayed on a parameter setting screen  901 . In this example, the parameters include a visualization object  905 , an abstraction level  903  of the entire parts, and a simulation step cycle  902  of each model. 
     If the user who created the subsystem granted authority for change/reference using the user terminal  107  in advance, a user of the subsystem can refer to/change the detailed parameters of the individual parts constituting the subsystem or add a new simulation model or visualization object in the subsystem. 
       FIG. 9  shows a configuration example when it is necessary to expressly designate software used in the individual parts as simulation objects in the simulation task input device  704  of the dynamic computational resource distribution system  100 .  FIG. 9  differs from  FIG. 7  in that tools of all the parts displayed on a tool palette  1000  are designated. A method for arrangement on the task configuration display region  801  and a method for setting operation parameters are common to the above case of  FIG. 7 . 
     According to the present invention, the configuration of the simulation task input device  704  may include all or some of the configuration example of  FIG. 7 , that of  FIG. 8  and that of  FIG. 9  without being limited to any one of them. 
       FIG. 10  shows a screen image showing an example of a user interface of a simulation task. This user interface presents an allocation result of the simulation task configuration to the simulation computational resources  101  to the user terminal  107 . In this embodiment, the screen display of the simulation task input device  704  is reused and a planned end time of the simulation, total cost for the simulation and its breakdown are displayed on this screen. 
     Two methods, i.e. a method for designating a time at which the simulation is desired to be finished as in  FIG. 10  and a method for designating the elapse of time are supposed as a method for presenting the planed end time of the simulation. In the present invention, a widely or publicly known technology may be used for this designation method. Further, a method for presenting a computational resource allocation result is not limited to the method shown in  FIG. 10 . 
     The task creation operation described in from  FIG. 7  to  FIG. 10  is defined to be an operation of receiving a created simulation configuration as an input from the user terminal  107  using the simulation task input device  704  of the dynamic computational resource distribution system  100  and converting it into an executable sequence of a simulation task configuration. 
     In creating the simulation task configuration, parameters of the simulation or computer configuration are adjusted in conformity with the granularity of a simulation model and characteristics of a simulator for executing the simulation model. 
     The granularity of the simulation model is the size of a minimum unit in the simulation model. A abstraction level largely differs depending on the simulation model, for example, between modeling with a low abstraction level such as a signal line level in SystemC and modeling with a high abstraction level such as a data communication level. This largely changes computation amount necessary for execution of a simulation and communication traffic between parts in a directly coupling relationship. 
     Generally, the lower abstraction level a simulation model has, the more computation amount and communication traffic are necessary, but it is possible to obtain detailed internal information. On the other hand, the higher abstraction level a simulation model has, the less computation amount and communication traffic are necessary, but time accuracy is low and only a limited internal state can be obtained. 
     In the case of connecting two or more simulation models having different granularities, it is necessary to synchronize data between the simulation models at regular time intervals. If connection is made without optimization here, the simulation is executed with the granularity of the coarse model and the overall simulation speed is reduced. 
     Thus, a technique for improving the overall simulation speed by optimizing a synchronization cycle of data in conformity with a site where the simulation is desired to be visualized is important. However, optimization of the synchronization cycle cannot be conclusively estimated before execution of the simulation. Therefore, in the present system, a technique for optimizing a simulation configuration is adopted which treats the configuration of a simulation executed in the past and system loads at the time of executing this simulation configuration as learning data. 
       FIG. 11  shows an example in which a simulation task configuration  1101  is created by setting a simulation of the engine control ECU as a simulation task in the case of developing a control system for an internal combustion engine as an embedded system. Software for executing each simulation (execution tool in  FIG. 11 ), a model for executing the simulation (used model in  FIG. 11 ), parameters to be used (used parameters) and identifiers of the cluster nodes  1400  for executing the simulations (execution node in  FIG. 11 ) are allocated to the engine control ECU, the air flow meter, the injector and the engine as simulation elements. 
       FIG. 12  shows a flow chart of task creation by the simulation task creating device  705  of the dynamic computational resource distribution system  100 . This corresponds to Step  501  of creating the simulation task and Step  502  of recording the task configuration in  FIG. 5 . A task creation process of the simulation task creating device  705  is described below. 
     In Step  1203 , the simulation task creating device  705  creates a task using a simulation configuration created using the simulation task input device  704  as an input. 
     In Step  1204 , the simulation task creating device  705  relates the parts included in the simulation configuration to the simulators to be executed respectively. In relating the parts and the simulators, the types of the simulators (simulation software) necessary to execute the respective parts included in the simulation configuration and information on the granularities of simulation models are obtained by a search (Step  1210 ) in the tool/model database  709  in which information on the simulation models used in the simulation configuration is recorded. 
     In obtaining, the simulation task creating device  705  refers to the simulation configuration history database  721  in which the simulation task configurations executed in the past are recorded (Step  1212 ). In finding out a history of execution of an equivalent configuration, it is possible to reuse the history data of the simulation configuration history database  721  without referring to the tool/model database  709 . 
     Subsequently, in Step  1205 , the simulation task creating device  705  allocates tasks of the simulators and the simulation models to the simulation computational resources  101 . At this time, a computational resource management database  706  is referred to (Step  1211 ). Specifically, the tasks of the simulators and the simulation models are allocated to the simulation computational resources  101  to simulate the individual parts of the simulation configuration based on requested computation amounts and communication traffics of the individual parts, and information on computation capability and communication capacity of the simulation computational resources  101  and usage statuses of computational resources recorded in the computational resource management database  706  to be described later. 
     In task allocation, whether to arrange the cluster nodes  1400  at close positions or at distant positions is determined according to the volume of the communication traffic between the parts. Further, the tasks with huge communication traffic are allocated to the same node. Further, since execution times and data are synchronized between the parts by TCP/IP communication, port numbers used in data communication are also allocated. 
     Further, the simulation task creating device  705  also couples the simulation result visualization unit  715  and a user interface for presenting the simulation mode in the case of including the simulation result visualization unit  715  that needs to keep displaying a result during the execution of the simulation. 
     When allocation of the simulation tasks to the simulation computational resources  101  is completed, the simulation task creating device  705  adjusts parameters of the individual simulation tasks in next Step  1206 . 
     Adjusting the parameters of the simulation tasks includes referring to the simulation configuration history database  721  to searching for histories of parameters of the simulators when a simulation having similar parts, coupling relationship of the parts and cluster arrangement was executed for combinations of the simulators and the simulation models (Step  1212 ). 
     If a result corresponding to the above search conditions is found, parameters of this simulation are used. If no search result is found, similar configuration histories in the parameters input in the simulation task input device  704  and the simulation configuration history database  721  are searched for and simulator parameters obtained from a configuration with a highly effective simulation result are generated. 
     The effectiveness of the simulation result is a numerical value evaluating whether or not the simulation result indicates an analysis result and an execution speed meeting the user&#39;s desire by analyzing the user&#39;s behavior after the execution of the simulation. A flow of simulation result effectiveness analysis is described later. 
     In Step  1207 , the simulation task creating device  705  confirms a command list  1202  of the simulation tasks to be executed in the simulation computational resources  101  as illustrated in  FIG. 23  by confirming the execution parameters corresponding to each combination of a simulator and a simulation model. 
     By the above process, the types and numbers of the simulators and simulation visualization units  715 , the amount of computational resource, and a coupling relationship of the computational resources necessary for the simulation can be known. Based on these, it can be predicted the amount of time and computational resources required by a similar simulation by referring to the simulation configuration history database  721 . 
     When anticipated values of the time and used resource are calculated, the simulation task creating device  705  calculates anticipated cost of the simulation to be presented to the user from the user terminal  107 . The above anticipated values are presented to the user. The present system waits until receiving an instruction to execute the simulation or recreate simulation tasks from the user terminal  107 . 
     If it is instructed to recreate the simulation tasks from the user terminal  107 , the simulation task creating device  705  reduces task creation accuracy of the simulation configuration presented to the user terminal  107  and creates simulation tasks again using different generation parameters (simulation elements). 
     The task creation accuracy is a numerical value given to each simulation task created by the simulation task creating device  705  and calculated by subtracting 1 or adding 1 based on effectiveness evaluation of the user on the executed simulation tasks. 
     On the other hand, if an execution instruction is given from the user terminal  107 , the simulation task creating device  705  transfers the command list  1202  to the task issuing device  723  to start the simulation. A widely or publicly known technology may be used for an estimation algorithm of a degree of similarity between the simulation configuration and the history data in the simulation task creating device  705  except in including the operation flow described with reference to  FIG. 12 . 
     In Step  1208 , a computing resource load measuring device  712  observes system loads in the simulation computational resources  101  during the execution of the simulation and records its observation result. Specifically, the system loads (e.g. processor utilization rates) of the respective cluster nodes  1400  of the simulation computational resources  101  are obtained and recorded in the resource usage management database. 
     In Step  1209 , the simulation task creating device  705  analyzes the simulation result and the configuration of the executed simulation after execution of the simulation and evaluates the effectiveness of this simulation. 
     After execution of the simulation, the user confirms the visualized simulation result in the user terminal  107 . Which action the user will take according to this result can be obtained by the user behavior statistics device  713 . 
     If it is revealed from the measurement result of the user behavior statistics device  713  that the user receives the simulation result in the user terminal  107  and repeatedly executes the simulation having the same part configuration again while changing the parameters relating to the operations of the simulators, the simulation task creating device  705  determines that the user is not satisfied with automatic allocation capability by the simulation task creating device  705  and reduces the task creation accuracy of the simulation configuration history. 
     If it is revealed from the measurement result of the user behavior statistics device  713  that the user receives the simulation result in the user terminal  107  and uses the exact same part configuration and simulation operation parameters, the simulation task creating device  705  increases the task creation accuracy of the corresponding simulation configuration history. The simulation task creating device  705  uses the effectiveness of each configuration history entry of the simulation configuration history database  721  so that a highly effective simulation configuration history is used in the future. 
     By the above mechanism, the simulation task creating device  705  can improve its own task creation accuracy. 
     Hereinafter, table configuration examples of the databases used in the task creating device  705  and the like are described. The tool/model database  709  is a database for storing information on arbitrary simulation models usable in the present system. A table configuration  1200  of  FIG. 19  shows an example of a table configuration of the tool/model database  709 . 
     In this embodiment, the tool/model database  709  stores identifiers (part name in  FIG. 19 ) of the simulation models, identifiers (tool in  FIG. 19 ) of the simulators capable of executing the simulation models, version information (version in  FIG. 19 ) of the executable simulators, granularities of the simulation models (model granularity in  FIG. 19 ) and the numbers of input/output ports of the simulation models as connection information in  FIG. 19 . This table configuration is a minimum table configuration in realizing the present invention and information to be stored may be further increased. 
     The computational resource management database  706  is a database for managing the state of the simulation computational resources  101  of the present system.  FIG. 24  shows an example of a table configuration of the computational resource management database  706 . 
     In this embodiment, the computational resource management database  706  is a database for storing computing capabilities, node position information, used states, planed return times from the used states and the like of the cluster nodes  1400  constituting the simulation computational resources  101 . 
     In  FIG. 24 , classes  2401  of the cluster nodes are obtained by classifying the simulation computational resources  101  according to its CPU performance and RAM capacity. The classes of the cluster nodes are used for cost calculation in execution of the simulation to be described later. 
     In this embodiment, position information of target cluster nodes on the network are stored under node arrangement  2402 . In this embodiment, IP addresses are used as position information on the network. The positional relationship on the network can be grasped from the IP addresses and communication traffic can be estimated based on the positional relationship on the network. Generally, the nodes having closer IP addresses can support high communication traffic. 
     This table configuration is a minimum table configuration in realizing the present invention and information to be stored may be further increased. 
     The simulation configuration history database  711  of the dynamic computational resource distribution system  100  is a database for storing the configuration of a simulation task created by the simulation task creating device  705 , i.e. the types of simulators used in a certain simulation, simulation models, a coupling relationship among the simulators (simulation configuration), parameters used in the simulators and effectiveness of an execution result of the simulation configuration. 
       FIG. 26A  shows an example of a simulation configuration table  2600  of the simulation configuration history database  711 . In this embodiment, identifiers of simulations (simulation ID in  FIG. 26A ), start times (start time in  FIG. 26A ), target end times and actual end times (actual end time in  FIG. 26A ) of the simulations, a link to another table storing the simulation configuration (simulation configuration file path in  FIG. 26A ) and simulation effectiveness are stored. 
       FIG. 26B  shows an example of a simulation configuration table  2601  of the simulation configuration history database  711 . In this embodiment, identifiers of simulators configuration (simulation ID in  FIG. 26B ), simulator types, file storage destinations of simulation models, and identifiers of simulation models which directly exchange data at the time of executing the simulation (neighboring configuration ID in  FIG. 26B ) are stored. As long as the information shown in  FIGS. 26A ,  26 B is included, a widely or publicly known technology may be used for other parts of the configuration of this database. 
     The computing resource load measuring device  712  can be realized, for example, by a system status obtaining program as a standard program of the OS introduced by a system provider and installed in the simulation computational resources  101 . A widely or publicly known technology may be used for the detail of the computing resource load measuring device  712  except that the execution times of the processes, the CPU loads and the RAM usage amounts can be recorded. As shown in  FIG. 3 , a program for obtaining the load information of each of the cluster nodes  1400  may be executed by the computer of the system load/user behavior monitoring system  103 . 
     A configuration example of the simulation computational resources  101  is described using  FIGS. 13 ,  14 .  FIG. 14  shows an example of a minimum structure of a cluster as a constituent element of the simulation computational resources  101 .  FIG. 13  shows a configuration example of the cluster nodes as constituent elements of the cluster. The simulation computational resources  101  have a cluster minimum structure  1403  in which one or more cluster nodes  1400  and one or more storage systems  1402  are connected to each other via a communication network  1401 . 
     Further, the simulation computational resources  101  can have a structure in which one cluster minimum structure  1403  or a plurality of cluster minimum structures  1403  are connected by the communication network  1401 . Any one of LAN (Local Area Network), Internet, WAN (Wide Area Network), dedicated line, wireless network, public network, mobile telephone network can be employed as the communication network  1401 , and the type of the network and a connection structure do not matter. A virtual dedicated network technology such as VPN (Virtual Private Network) may be sometimes applied to the communication network  1401 . 
     A configuration example of the cluster node  1400  is described using  FIG. 13 . A basic configuration of the cluster node  1400  includes elements such as one or more processors  1300 , one or more memories  1303 , a controller  1301 , one or more accelerators  1302 , and a network interface  1304 . The number of each element and connection relationship of the elements are not limited. 
     Using  FIGS. 6 and 3 , an example of a process in the development progress/tool usage status/system usage fee confirmation mode  317  is described. 
     Information provided in the development progress/tool usage status/system usage fee confirmation mode  317  is regularly analyzed using latest data given by a search  600  of system information at that time by a method to be described later. Specifically, a development progress selecting device  718  in the system load/user behavior monitoring system  103  analyzes the above information using the latest data in creation  603  of a development progress report and creation  604  of a software usage status report. A system usage fee generating device  716  analyzes the above information using the latest data in creation  601  of a system usage fee report and creation  602  of a license fee report. 
     The development progress report is recorded in a development progress information database  720 , the software usage status report is recorded in a tool usage status database  719 , and the system usage fee report and the license fee report are recorded in a billing management database  717 . 
     The user who selected the development progress/tool usage status/system usage fee confirmation mode  317  in Step  302  selects the type of the information desired to be confirmed from the development progress report, the tool usage status report and a system usage confirmation report in Step  313 . 
     When the information to be used is selected in the user terminal  107 , the present system searches the development progress information database  720 , the tool usage status database  719  and the billing management database  717  for the corresponding latest report. If the corresponding report data is found, it is presented to the user terminal  107  via the screen data transmitting device  701  in Step  314 . 
     The user can limit information browsable by the user in advance in concluding a usage contract of the present system. For example, the user who develops using the present system can receive the development progress report and the usage fee information, but cannot browse the license fee information. 
     A procedure of analyzing information in the system usage fee generating device  716  and the development progress selecting device  718  in the system load/user behavior monitoring system  103  and configuration examples of databases necessary at that time are described below. 
       FIG. 15A  shows a procedure of calculating a usage fee of the present system to be charged to the user using the user terminal  107  and a license fee to be paid to the software provider from the information in the operation history database  708 , the resource usage management database  711  and a resource price database  710 . 
     First, a process of calculating the system usage fee to be charged to the user is described. In Steps  1500  and  1501 , the system usage fee generating device  716  searches, for each user, the resource usage management database  711  and the operation history database  708  respectively for a load history of the simulation computational resources  101  and a GUI operation history within a usage time by the user of the work computer system  106 . 
     In Step  1503 , the system usage fee generating device  716  selects CPU usage, RAM usage and required time of each used function based on a combination of the load history of the simulation computational resources  101  and the GUI operation history of the work computer system  106 . 
     On the other hand, in Step  1502 , the system usage fee generating device  716  searches the resource price database  710  for a computational resource unit price and a tool unit price for each tool used from the user terminal  107 , using a used computation node as a keyword. 
     The system usage fee generating device  716  calculates the data collected in above Steps  1502 ,  1503  in accordance with the following equation in Step  1504 :
 
(CPU usage×RAM usage×computational resource unit price+tool unit price)×usage time.
 
This equation is equivalent to a calculation of multiplying the usage of the computational resources by the usage unit price of the computational resources. The system usage fee generating device  716  calculates and tabulates the system usage fee corresponding to the usage of the functions of the present system for each user of the user terminal  107 .
 
     Subsequently, in Step  1513 , the system usage fee generating device  716  searches the resource usage management database  711  for the storage usage of the user of the user terminal  107  and searches the resource price database  710  for the storage unit price. Further, in Step  1505 , the storage usage and the storage unit price are multiplied and the multiplication result is added to the system usage fee as the storage usage fee. The resource price database  710  is described later. 
     By Step  1505 , the system usage amount for the user is given by: 
     
       
         
           
             
               
                 
                   
                     
                       ∑ 
                       UsedTool 
                     
                     ⁢ 
                     
                       TaskRequiredTime 
                       × 
                       
                         ( 
                         
                           
                             ComputationalResourceUnitPrice 
                             × 
                             CPUUsage 
                             × 
                             
                                 
                             
                             ⁢ 
                             RAMUsage 
                           
                           + 
                           ToolFunctionUnitPrice 
                         
                         ) 
                       
                     
                   
                   + 
                   
                     StorageUsage 
                     × 
                     StorageUnitPrice 
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     In Step  1506 , the system usage fee generating device  716  compiles the total and particulars of the system usage fee added with the storage usage fee calculated above and creates a system usage fee report  2700  as illustrated in  FIG. 27 . Finally, in Step  1512 , the created system usage fee report  2700  is registered in the billing management database  717 . 
     Next, a process of calculating the software license fee to be paid to the software provider is described using  FIG. 15B . In Steps  1507  and  1501 , the system usage fee generating device  716  searches the resource usage management database  711  and the operation history database  708  respectively for a load history of the simulation computational resources  101  of each software and a GUI operation history within a usage time by the user of the work computer system  106 . 
     Subsequently, in Step  1509 , a minute required time of each used function is selected based on a combination of the load history of the simulation computational resources  101  and the GUI operation history of the work computer system  106 . 
     On the other hand, in Step  1508 , the system usage fee generating device  716  searches the resource price database  710  for a software usage unit price using the function of the software as a keyword and multiplies it by the required time selected above. By Step  1510 , the software license fee to be paid to the software provider is calculated by: 
     
       
         
           
             
               
                 
                   
                     ∑ 
                     UsedTool 
                   
                   ⁢ 
                   
                     TaskRequiredTime 
                     × 
                     ToolFunctionUnitPrice 
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
     In Step  1511 , the system usage fee generating device  716  compiles the total and particulars of the calculated software license fee and creates a license fee report  2800  as illustrated in  FIG. 28 . Finally, in Step  1512 , the created license fee report  2800  is registered in the billing management database  717 . 
     By the above, the system usage fee generating device  716  creates the system usage fee report  2700  and the license fee report  2800 . 
     Next, the detail of the resource price database  710  described with reference to  FIGS. 15A and 15B  is described with reference to  FIG. 20 . The resource price database  710  in the system load/user behavior monitoring system  103  stores contract information on the license fee and the system usage fee concluded with the software provider and the user in advance. 
     A table configuration example of the resource price database  710  is described using  FIG. 20 . A storage price table  1730  of the resource price database  710  stores capability, capacity and unit price per unit usage time for each class of storage in the present system. 
     A cluster node price table  1740  of the resource price database  710  stores the installed CPU, the hardware type, the amount of the installed memory and the unit price per time/unit CPU usage/unit RAM usage for each type of the node. 
     A tool price table  1750  of the resource price database  710  stores vender information and unit price per function/unit time for each software and each function. Unit price information includes two unit prices, i.e. a unit price to be paid to the software provider and a unit price to be charged to the user. 
     The resource usage management database  711  in the system load/user behavior monitoring system  103  is a database for recording usage loads on the simulation computational resources  101 , the work environment computational resources  722  and the user file storage  707 . 
       FIG. 17  shows a table configuration example of the resource usage management database  711 . The resource usage management database  711  is configured to include a storage usage history table  1700  storing a usage history of the user file storage  707  used by the user terminal  107 , a system load history table  1710  storing load histories of the cluster nodes  1400  used in the simulation computational resources  101  and a remote OS usage time table  1720 . 
     The storage usage history table  1700  records information including the usage for each storage area secured on the user file storage  707  by the user of the user terminal  107 . In this embodiment, user identifiers, used storage amounts and storage class identifiers are recorded. 
     The storage usage of each user in the user file storage  707  in the work computer system  106  is sequentially monitored by a storage usage tabulation program executed by the system load/user behavior monitoring system  103 . 
     The system load history table  1710  stores system loads of tasks executed on the simulation computational resources  101  by the user of the user terminal  107 . In this embodiment, the used software, task start times, task end times, the types of the used cluster nodes, average values and peak values of the CPU usage and the memory usage are recorded. 
     The remote OS usage time table  1720  records the usage time of the user in the work environment computational resources  722  in the work computer system  106 . In this embodiment, the user identifier, the login time to and the logout time from the work environment computational resources  722  are recorded. The operation history database  708  is a database for holding an operation performed on the GUI or file on the present system by the user via the user terminal  107  and a behavior analyzed from the operation history. 
       FIG. 18  shows a table configuration example of the operation history database  708 . The operation history database  708  is composed of a user behavior raw data table  1820  storing a usage history of the present system by the user from the user terminal  107 , an event table  1810  storing an analysis result of the user behavior statistics device  713 , and a file history table  1800  storing a history of accessing the user file storage  707  from the user terminal  107  for each user. 
     The user behavior raw database  1820  holds data obtained by the user behavior statistics device  713  from operations of the user on the simulation task input device  704  and the work computational resources  722  as they are. Thus, only an event history of GUI parts of the individual tools such as operations on a mouse, entered texts and the like are recorded in this table  1820 . 
     The event table  1810  stores data obtained by template analysis of data of the user behavior raw data table  1820  and the file history table  1800  by the user behavior statistics device  713 . 
     The user behavior statistics device  713  includes stored computer operations corresponding to a GUI operation sequence (template) as a pair, checks the GUI operation history of the user and the template against each other, and outputs a computer operation event determined to have a highest corresponding probability by a statistical means. In the present application, this checking is called template analysis. 
     By the template analysis of the user behavior statistics device  713 , an operation event for each tool, e.g. which part was handled or which option was selected on the tool can be estimated from the GUI operation history sequence of the user behavior raw data table  1820 . In this embodiment, the event table stores the user identifier, the type of the software, the occurrence time of an event and the content of the event. 
     In this embodiment, a widely or publicly known technology may be used for the user behavior statistics device  713  concerning the algorithm of the template analysis except for the functions described above. 
     In selecting a development progress status and a tool usage status, the present system regularly analyzes information without receiving a request from the user and stores latest report files in the databases each time. According to an information analysis method of the present system, a process of producing a simulation result as a development result from a software part as a material is estimated from the usage of the tools and accesses to files. 
     An example of a process of the development progress selecting device  718  to select a development progress status by referring to a behavior history (operation history database  708 ) of the user is described using  FIG. 16A . In Step  1607 , the development progress selecting device  718  searches for a job of each user. This search is on the premise that a job given to a user or a user group using the user terminal  107 , e.g. a simulation including a certain part and software is registered in the system by a manager of the user or the user group or the user himself. A widely or publicly known technology may be used for methods for inputting and storing this job. 
     Subsequently, in Step  1608 , the development progress selecting device  718  searches the simulation configuration history database  721  of the dynamic computational resource distribution system  100  and the resource usage management database  711  and searches for a history of a simulation task configuration corresponding to the job searched for in Step  1607 . If a search result is found, a dependency relationship of the information relating to this simulation is analyzed in next Step  1609 . 
     The development progress selecting device  718  executes a search using the identification number of the user or the user group and the corresponding simulation as keywords in Step  1600 . In the resource usage management database  711 , the execution time of the simulation and the information on the software and the file used in the simulation are searched for. In the operation history database  708 , history information of information files on the GUI operations, usage events of the functions of the software and times at which the events occurred are searched for. 
     In Step  1600 , the development progress selecting device  718  tabulates search results and generates an information flow graph  2100  as shown in  FIG. 21 . 
     The information flow graph  2100  of  FIG. 21  has a graph structure that a simulation task given to the user by analyzing a temporal sequence and the flow of operations is a base point, simulation trials and file changes are points and a dependency relationship of the information is an edge. If there is a Step in which the corresponding information is referred to at a later time for information or a file changed in a certain Step such as Steps  2101  and  2102  of  FIG. 21 , a dependency relationship is thought to exist between two Steps. 
     If a plurality of sequences having the same dependency relationship appear through time, the development progress selecting device  718  collectively visualizes these sequences having the dependency relationship as a loop  2103 . 
     In Step  1602 , the development progress selecting device  718  can select a list of files or software created or changed in the process of executing the simulation job given to the user by the information flow graph  2100  obtained in above Step  1600  and analyzing the development information. In Step  1603 , the development progress selecting device  718  issues a development progress report including an selection result and records it in the development progress information database  720 . 
     The development progress selecting device  718  also analyzes a loop structure of the information flow graph  2100 . An example of an analysis of the loop structure is as below. If the simulation trial is continued without changing the simulation configuration or the parameters, a self-loop, i.e. a part where an edge extends from a certain point to itself is present in this simulation part in the information flow graph  2100 . The loop structure is analyzed by selecting a layered structure of the loop, measuring work efficiency of a work flow and selecting an achievement degree of the job given to the user besides selecting such a self-loop. 
     The development progress selecting device  718  creates a development progress report  1604  (illustrated in  FIG. 22 ) including a progress rate of the simulation process selected in Step  1602 , the information of the file created in executing the simulation, the number of executed simulations and effectiveness thereof and stores it in the development progress information database  720 . The development progress report  1604  of  FIG. 22  is absolutely an example of its configuration and a widely or publicly known technology may be used for a method for adding and expressing information other than those listed above. 
     Finally, selection of the software usage status by the behavior history of the user executed by the development progress selecting device  718  is described using  FIG. 16B . 
     Since Steps  1607  to  1600  of  FIG. 16B  are the same as Steps  1607  to  1600  of the development progress status selection flow by the behavior history of the user shown in  FIG. 16A , these Steps are not repetitively described. In Steps  1608 ,  1609  of  FIG. 16B , searches in the resource usage management database  711  and the simulation configuration history database  721 , and the information flow analysis and the generation of the information flow graph  2100  are common to the analysis of the development progress described with reference to  FIG. 16A . However, a search is executed using the ID of the software installed into the present system as a keyword in the selection of the software usage status shown in  FIG. 16B . 
     The development progress selecting device  718  obtains the functions of the software and a usage frequency distribution of the parameters from the event table  1810  of the operation history database  708 . Further, the files used in association with the software or information on another software are collected based on the information flow graph  2100  used in the development progress status selection described above. 
     In Step  1605 , the development progress selecting device  718  processes the collected information into a form that can be visualized as a tool usage status report  2500  as shown in  FIG. 25 . The tool usage status report  2500  is stored in the tool usage status database  719  and issued to the software provider (Step  1606 ). 
     The tool usage status report  2500  of  FIG. 25  is absolutely an example of its configuration and a widely or publicly known technology may be used for a method for adding and expressing information other than those listed above. 
     As described above, in this embodiment, the dynamic computational resource distribution system calculates an arrangement relationship of simulators on the simulation computational resources so as to execute a simulation configuration optimally based on a coupling relationship of parts (mechanism to be developed, hardware, software) in a simulation task input from the user terminal, and constructs an actual simulation task. In this way, a simulation can be executed at a high speed. 
     Further, for each user of the embedded system development, a simulation or software usage history is selected and recorded with high accuracy, and a development process of each user is selected from the recorded information. In this way, the progress of each user can be easily managed. 
     Further, by unifying the work computational resources  722  and the simulation computational resources  101 , initial investment for maintenance of a development environment and maintenance cost can be reduced. Furthermore, by unifying the work computational resources  722  and the simulation computational resources  101 , design files (simulation models, parameters, etc.) can be shared and efficiency in embedded system development can be improved even in the case of simultaneous development at a plurality of sites. Particularly, since the simulators or the software are all managed on the unified computer system, embedded system developers need not purchase the software in advance or maintain the software by themselves. 
     Further, since the cooperation of a plurality of simulators and adjustment of simulator parameters are automated by reusing the past parameters and simulation configurations based on the information collected for each user, quick and accurate simulations can be easily executed even if developers (users) do not have detailed know-how. In this way, efficiency in embedded system development can be improved. 
     Further, since the developed software and simulation results using this software are safely transferred in the unified computer system, design files can be more easily shared and a risk of leaking information to outsiders can be suppressed. 
     Second Embodiment 
       FIG. 29  is a block diagram schematically showing an example of a second embodiment of the present invention. The second embodiment includes a high-security file transmission system  105  in addition to the configuration of the first embodiment. A user terminal  107  or a provider terminal  108  can receive a system usage report, a license fee report, a development progress report and a software usage status report provided from a system load/user behavior monitoring system  103  via the high-security file transmission system  105 . 
     This eliminates the need to directly connect the user terminal  107  and the provider terminal  108  to the system load/user behavior monitoring system  103  of the present system in obtaining and confirming the reports. This eliminates the need to connect the user terminal  107  and the like to a dynamic computational resource distribution system  100 , a simulation computational resources  101 , a simulation result visualization system  102  and the system load/user behavior monitoring system  103  other than during a development operation, wherefore security can be further improved. 
     Note that the function of the development progress selecting device  718  constituting the system load/user behavior monitoring system  103  of the first embodiment shown in  FIG. 3  may be incorporated into the system usage fee generating device for calculating a system usage fee and a license usage fee incurred by using the present system. 
     The system usage fee generating device selects a development progress selecting the user&#39;s development process in the present system, calculates a system usage fee to be demanded and a license fee to be paid and creates a development progress report and a software usage status report of each user based on screen operation information and file operation information of each user and loads on the simulation computational resources in the present system. 
     Further, the work computer system  106  of the first embodiment shown in  FIG. 3  functions as work computational resources arranged on the network and including a computer remotely operable from the user terminal  107 . Further, the work computer system  106  functions as a user file storage arranged on the network, storing created design files from the user terminal  107  and including a storage which can be shared by other user terminal(s)  107 . 
     Furthermore, the work computer system  106  functions as a work environment providing device as a device for providing the work computational resources and the user file storage in combination in response to a request from the user terminal  107 . In this way, the work computer system  106  realizes design file creation in the user terminal  107  and sharing of design files by a plurality of user terminals  107 . 
     Further, the simulation task input device  704  of the dynamic computational resource distribution system  100  of the first embodiment shown in  FIG. 3  includes the tool palette from which simulation models usable from the user terminal  107  are selectable and the model construction display region on which simulation models can be arranged. The tool palette and the model construction display region are GUIs enabling the simulation task input device  704  to configure a simulation according to an input from the user terminal  107 . 
     The tool palette provides a GUI in which one or more simulation models having specific detailed information deleted are arranged. On the model construction display region, simulation models selected from the tool palette are arranged according to an input from the user terminal  107 , the arranged models are connected by lines, and information specific to the simulation models is displayed and set. According to a screen operation using the tool palette and the model construction display region, the simulation task input device  704  constructs a simulation configuration. 
     Although the devices in the dynamic computational resource distribution system  100 , the simulation computational resources  101 , the simulation result visualization system  102 , the system load/user behavior monitoring system  103 , the work computer system  106  and the screen data transmission system  104  using secure communication of the first embodiment shown in  FIG. 3  are expressed as computers, software executed in the devices may be executed by one computer. In this case, the devices in the systems  101  to  104  may be, for example, termed as a user behavior statistics unit. 
     The software program operating in the present system can be stored in a computer-readable medium after or without being compressed. Any type of medium such as a semiconductor memory, a magnetic memory or an optical disk may be used. 
     Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited to such a specific configuration and includes various changes and equivalent configurations within the gist of accompanying claims. 
     INDUSTRIAL APPLICABILITY 
     As described above, the present invention can be applied to a computer system for designing by executing a simulation and a program of a development system.