Information processing system and method for same

Abstract

A mobile agent mediates cooperation among schedulers by executing a cooperation protocol. For heuristics such as strategies and the order in which variables are decided, which are used as criteria of selecting the value of a variable from candidates, when the heuristics are to be built into a solving method of a constraint satisfaction problem, processes with regard to these heuristics are so substantially localized as to be capable of parallel execution. These processes capable of parallel execution, as autonomous operations of different mobile agents, can be under modeling in natural form, resulting in easy installation. This facilitates software construction for reflecting the heuristics in a solving method of a constraint satisfaction problem, as well as improves the maintainability and extendibility of software.

1 . A mobile agent which migrates among a plurality of processing units that form a distributed system, comprising: 
 storage means for storing cooperation problem solving knowledge that represents how said plurality of processing units cooperate with each other to perform said problem solving;    communication means for communicating with said plurality of processing units to receive information from each processing unit and to transmit information generated from one or both of said cooperation problem solving knowledge and the received information to each processing unit; and    processing means for generating the information to be transmitted to each processing unit by making use of said cooperation problem solving knowledge when said plurality of processing units are required to cooperate with each other, and for mediating cooperation among said processing units by causing said communication means to transmit the generated information to each processing unit.    
   
   
       2 . A mobile agent according to  claim 1 , wherein said each processing unit is a scheduler that has a plurality of variables and performs a constraint satisfaction problem solving by assigning for each variable a value that is not contrary to a constraint among the variables, wherein said mobile agent comprises generation means for generating an agent in correspondence to each alternative when they exist as a plurality of alternatives with regard to the assignment of values for the variables, and wherein said each agent corresponding to each alternative executes a cooperation protocol among said schedulers independently of the other agents and according to the alternative.  
   
   
       3 . A mobile agent according to  claim 1 , wherein said each processing unit is a scheduler that has a plurality of variables and performs a constraint satisfaction problem solving by assigning for each variable a value that is not contrary to a constraint among the variables, wherein said mobile agent comprises generation means for generating an agent in correspondence to each strategy when they exist as a plurality of strategies if they exist as a plurality of strategies of what criterion is used for selection of a value to be assigned, and wherein said each agent corresponding to each strategy searches for a solution by assigning values for the valuables independently of the other agents, at the same time, and according to the strategy.  
   
   
       4 . A mobile agent according to  claim 1 , wherein said each processing unit is a scheduler that has a plurality of variables and performs a constraint satisfaction problem solving by assigning for each variable a value that is not contrary to a constraint among the variables, wherein said mobile agent comprises generation means for generating an agent in correspondence to each variable when there are a plurality of schedulers that have variables being approximately equal in priority with regard to the order in which values are decided, wherein said each agent corresponding to each variable searches for a solution by assigning values for the valuables independently of the other agents and at the same time, and wherein said mobile agent comprises a means for merging each agent by changing each variable so as to minimize the change of each variable according to said constraint among the variables.  
   
   
       5 . A mobile agent according to  claim 1 , wherein said each processing unit comprises communication means for communicating with said mobile agent in a predetermined format.  
   
   
       6 . A mobile agent according to  claim 5 , wherein the mobile agent comprises: 
 second communication means for communicating with said each processing unit in said format; and    coordination means for performing coordination among said processing units.    
   
   
       7 . A mobile agent according to  claim 5 , wherein said each processing unit exists on a plurality of nodes, respectively, and wherein the mobile agent has the mobility to migrate among said nodes.  
   
   
       8 . A mobile agent according to  claim 6 , wherein at least one of said processing units comprises coordination means for performing coordination of the processing unit.  
   
   
       9 . A mobile agent according to  claim 6 , wherein said coordination means of the mobile agent comprises: 
 protocol management means for managing an interaction protocol that performs coordination among said processing units; and    status management means for performing said coordination by managing status of information processing based on said interaction protocol.    
   
   
       10 . A mobile agent according to  claim 1 , wherein the mobile agent comprises means for diminishing the mobile agent when the mobile agent completes cooperation among said processing units.  
   
   
       11 . An information processing system which has a plurality of nodes connected with one another through a network and performs information processing in a distributed manner by allowing a mediation agent to migrate among said nodes and to operate on each node, each of said the plurality of nodes comprising: 
 a constituent element which performs information processing on the node; and    an agent wrapper which has an access section for allowing said constituent element to operate according to processing procedures intrinsic thereto and a communication section performing a communication function with the mediation agent which migrates among said nodes through the network,    wherein each constituent element located on each of said nodes performs the processing procedures based on an interaction protocol which expresses a mutual action process between constituent elements on the basis of a message exchange rule between the constituent elements, the interaction protocol unique to each constituent element being described in the access section of said agent wrapper,    wherein each of said nodes has sections, which are implemented on the node by said mediation agent, including a communication section that exchanges messages with the communication section of the agent wrapper located on each node, a migration section that migrates among said nodes according to a message from each node, a storage section that stores an interaction protocol common to constituent elements for allowing the whole information processing system to operate in a coherent manner, and a load section that reads out an interaction protocol from said storage section based on a message from each node.    
   
   
       12 . An information processing system according to  claim 11 , wherein each of said nodes has said sections, which are implemented on the node by said mediation agent, including a storage section that stores a plurality of interaction protocols corresponding to respective states of the performance of information processing, and a state management section that reads out an interaction protocol corresponding to the current information processing state through said load section based on a message between each constituent element and said mediation agent.  
   
   
       13 . An information processing system according to  claim 12 , wherein the storage section is configured such that interaction protocols are stored therein per unit assembly of a plurality of states for information processing or interaction protocol.  
   
   
       14 . An information processing system according to  claim 12 , wherein the state management section is configured such that on premises preliminarily set individually to the plural states, the state management section calls up an interaction protocol suitable for the current information processing state and performs processing of each constituent element based on the called up interaction protocol.  
   
   
       15 . An information processing method which uses a plurality of nodes connected with one another through a network and performs information processing in a distributed manner by allowing a mediation agent to migrate among said nodes and to operate on each node, said method using an information processing system, the system comprising: 
 a constituent element which is located on each node and performs information processing on the node; and    an agent wrapper which is located on each node and has an access section for allowing said constituent element to operate according to processing procedures intrinsic thereto and a communication section performing a communication function with the mediation agent which migrates among said nodes through the network,    wherein each constituent element located on each of said nodes performs the processing procedures based on an interaction protocol which expresses a mutual action process between constituent elements on the basis of a message exchange rule between the constituent elements,    said method comprising the steps of.    describing the interaction protocol unique to each constituent element in the access section of said agent wrapper;    causing said mediation agent to implement sections on the node, the sections including a communication section that exchanges messages with the communication section of the agent wrapper located on each node, a migration section that migrates among said nodes according to a message from each node, a storage section that stores an interaction protocol common to constituent elements for allowing the whole information processing system to operate in a coherent manner, and a load section that reads out an interaction protocol from said storage section based on a message from each node;    performing processing with regard to problem solving procedures common to constituent elements, based on an interaction protocol read out from said storage section implemented by said mediation agent; and    performing a local processing unique to each constituent element, based on an interaction protocol described in the access section located on the node on which the constituent element located.    
   
   
       16 . An information processing method according to  claim 15 , wherein each of said nodes has said sections, which are implemented on the node by said mediation agent, including a storage section that stores a plurality of interaction protocols corresponding to respective states of the performance of information processing, and a state management section that reads out an interaction protocol corresponding to a current information processing state through said load section based on a message between each constituent element and said mediation agent.  
   
   
       17 . An information processing method according to  claim 16 , wherein the storage section is configured such that interaction protocols are stored therein per unit assembly of a plurality of states for information processing or interaction protocol.  
   
   
       18 . An information processing method according to  claim 16 , wherein the state management section is configured such that on premises preliminarily set individually to the plural states, the state management section calls up an interaction protocol suitable for the current information processing state and performs processing of each constituent element based on the called-up interaction protocol.  
   
   
       19 . A computer-readable storage medium storing a program for performing information processing, using a plurality of nodes connected with one another through a network and performs information processing in a distributed manner by allowing a mediation agent to migrate among said nodes and to operate on each node, said program comprising: 
 means for implementing an information processing system, the system comprising:    a constituent element which is located on each node and performs information processing on the node; and    an agent wrapper which is located on each node and has an access section for allowing said constituent element to operate according to processing procedures intrinsic thereto and a communication section performing a communication function with the mediation agent which migrates among said nodes through the network,    wherein each constituent element located on each of said nodes performs the processing procedures based on an interaction protocol which expresses a mutual action process between constituent elements on the basis of a message exchange rule between the constituent elements,    said program further comprising:    means for describing the interaction protocol unique to each constituent element in the access section of said agent wrapper:    means for causing said mediation agent to implement sections on the node, the sections including a communication section that exchanges messages with the communication section of the agent wrapper located on each node, a migration section that migrates among said nodes according to a message from each node, a storage section that stores an interaction protocol common to constituent elements for allowing the whole information processing system to operate in a coherent manner, and a load section that reads out an interaction protocol from said storage section based on a message from each node:    means for performing processing with regard to problem solving procedures common to constituent elements, based on an interaction protocol read out from said storage section implemented by said mediation agent; and    means for performing a local processing unique to each constituent element, based on an interaction protocol described in the access section located on the node on which the constituent element located.