Kiyoshi Itoh

Swarm Intelligence in the Optimization of Software Development Project Schedule

The Software Development Project Scheduling Problem is similar to the well-known Resource-Constrained Multi-Project Scheduling Problem (RCMPSP). It consists in determining a schedule of tasks taking into consideration resource availabilities and precedence constraints, while optimizing an objective. Like RCMPSP, it is an NP-hard problem. In this paper, a task segmentation scheme to schedule a software development project is proposed and the average duration of the multiple concurrent projects is minimized using the Particle Swarm Optimization (PSO) meta-heuristic. PSO is a recent meta-heuristic algorithm, known for its simplicity in programming and its rapid convergence. A series of experiments show optimum results for several software development schedule scenarios.

GA optimization of Petri net-modeled concurrent service systems

This paper deals with the performance modeling and the optimization of concurrent service systems. In large and complex service systems, asynchronous and concurrently occurring activities are common. Petri nets are ideal tools for modeling concurrent systems. However, Petri nets are lacking in time duration concept, in data collecting mechanism and in conjunctive logic on the preconditions of an event. These inherent limitations along with the state explosion problem severely restrict their scope of application. In this paper, we introduce the Client Server Petri net, which overcomes all these limitations. The Client Server Petri net is an extension of the Generalized Stochastic Petri net that allows greater flexibility in modeling and simulating concurrent systems. The total operational cost of service systems consists of service cost and waiting cost. The former is due to the hiring of service personnel, while the latter is due to the fact that customers weary of waiting may take their business somewhere else. The problem, in principle, can be formulated as a multi-objective optimization problem and then solved to obtain the Pareto-front. In this study, however, we formulate it as a single-objective optimization problem because optimization (minimization) of the total cost (service cost+waiting cost) is of paramount importance in economic models. Finding the optimal operational cost becomes a combinatorial optimization problem which we seek to minimize using the genetic algorithm, known for its robustness and versatility as an optimization meta-heuristic. We demonstrate the effectiveness of the novel Client Server Petri net model editor-simulator-optimizer with the practical example of an automobile purchase concurrent service system.

Designing Collaborative Work in IDEF0 Using Interface Model

Practical experience shows that the IDEF0 notations form a comprehensive and complete set of definitions, but also that the work associated with an actual implementation of the methodology reveals some problematic aspects surrounding use of the ICOM nota tions. In this paper, the authors introduce an interface model that aims to solve problems associated with implementation of the IDEF0 methodology.

Graphical editing and analysis system for network system (Geans)

Abstract Network analysis is powerful in building formal network models of various computational systems or social systems and obtaining their functions and performance exactly because of simplicity of binary relations in networks. Traditionally, it takes lots of effort in network analysis because network analysis was performed by the use of lots of numerical data in batch processing form. Effective network analysis activity, satisfying the system requirements based on consideration for such traditional manner with high cost, requires semiautomatic or computer aided man-machine facilities with interactive editing, analysis, and result viewing functions. We have developed Graphical Editing and Analysis system for Network System (Geans) on DEC PDP-11/34 minicomputer with a graphic display which enables us to edit or modify various network representations and analyze their qualitative and quantitative property, smoothly and interactively with the use of graphics and data abstraction. Geans is composed of a network editing system with effective use of a graphic display, a network data management system with systematic use of network data abstraction, a network analysis system with construction of shared library routines and specific object problem oriented routines, and a node/arc shape definition system. Geans has been applied to various network models such as a transportation analysis problem, PERT/CPM planning, Petri Net analysis and a guidance system for an urban railway network, and moreover it is being applied to other analysis areas as evolving itself.

An application of artificial intelligence to object-oriented performance design for real-time systems

The paper describes an application of artificial intelligence technology to the implementation of a rapid prototyping method in object-oriented performance design (OOPD) for real-time systems. OOPD consists of two prototyping phases for real-time systems. Each of these phases consists of three steps: prototype construction, prototype execution, and prototype evaluation. We present artificial intelligence based methods and tools to be applied to the individual steps. In the prototype construction step, a rapid construction mechanism using reusable software components is implemented based on planning. In the prototype execution step, a hybrid inference mechanism is used to execute the constructed prototype described in declarative knowledge representation. MENDEL, which is a Prolog based concurrent object-oriented language, can be used as a prototype construction tool and a prototype execution tool. In the prototype evaluation step, an expert system which is based on qualitative reasoning is implemented to detect and diagnose bottlenecks and generate an improvement plan for them. >

Qualitative reasoning-based parameter tuning on bottleneck of synchronized queueing network

The qualitative method is proposed for parameter tuning of synchronized queuing network bottlenecks (SQN). The bottleneck diagnosis expert system for SQN (BDES-S) can carry out parameter tuning in order to diagnose and improve bottlenecks of SQN. BDES-S can produce several alternative qualitative improvement plans for the bottleneck. BDES-S is a novel system for applying the qualitative reasoning to the SQN.<<ETX>>

TRANSOBJ: SOFTWARE PROTOTYPING ENVIRONMENT FOR REAL-TIME TRANSACTION-BASED SOFTWARE SYSTEM APPLICATIONS

A software prototyping environment called TransObj (TRANSaction and OBJect) is used for designing real-time Transaction-based Concurrent Software Systems (TCSS). In a TCSS design process, a software designer should perform both functional design and performance design. The designer should change his design view from a transaction-based paradigm to an object-based paradigm during the TCSS design process. Recognition of re-entrant functional objects and serially reusable functional objects in the TCSS should be required. TransObj includes the Stepwise Prototyping Method (SPM), and two SPM-based tools: Prolog-based TransObj (P-TransObj) and GPSS-based TransObj (G-TransObj). SPM enables the designer to advance both functional design and performance design for the TCSS prototype as controling the change of design view paradigms. P-TransObj mainly checks the prototype in a microscopic view on a personal computer. G-TransObj mainly checks the same prototype with a longer time span on a large-scale computer.

An Application of Artifical Intelligence to Prototyping Process in Performance Design for Real-time Systems

This paper describes an application of artificial intelligence technology to the implementation of a rapid prototyping method in Object-Oriented Performance Design (OOPD) for real-time systems. A prototyping process is composed of three steps: Prototype construction, Prototype execution, and Prototype evaluation. The authors present the following artificial intelligence based methods and tools to be applied to each step. In the prototype construction step, a rapid construction mechanism, using reusable software components, is implemented based on the planning method. In the prototype execution step, a hybrid inference mechanism is used to execute the constructed prototype which is described in declarative knowledge representation. In the prototype evaluation step, an expert system, which is based on qualitative reasoning, is implemented to detect and diagnose bottlenecks and generate an improvement plan for them.

Systematic integration of qualitative and quantitative parameter tuning methods for improving real-time system prototypes by AI techniques

In performance improvement, there are a number of parameter tuning plans for improving a real-time system prototype. The author has developed two knowledge-based expert systems, BDES and BIES. BDES qualitatively diagnoses or identities bottlenecks and their sources, and generates qualitative improvement plan. BIES quantitatively estimates the effects of the improvement for bottleneck and their sources on the whole queueing network. BDES and BIES assume a real-time transaction oriented concurrent software system: (TCSS) as a queueing network (QN). Performance of a TCSS can be highly improved in systematic fashion with the complementary, integrated use of qualitative reasoning and quantitative reasoning. BDES and BIES are the components of TransObj which the author developed for real-time system prototyping.<<ETX>>

Man-machine interactive guidance for urban railway networks

Abstract A passenger requires precise and timely guidance information about his path from origin to destination on an urban railway network, e.g. the shortest time path and the minimal cost path. Such two paths are not easy to estimate because the former path is dynamically varied in time-dependent fashion by the ununiformity of train traffic density on time and by the mixture of different train traffic scheduling systems of several companies and the latter path may be composed of one or more lines operated by several companies with their different fare systems. This paper clarifies smooth and effective interaction steps for the guidance for urban railway networks, enumerates I/O devices suitable for the effective guidance, enumerates data items to be required for the effective guidance, clarifies the relationships among them, describes the problems in solving the shortest time path and the minimal cost path, shows our newly devised two analysis algorithms, and shows the overview of the pilot system of our man-machine guidance system in terms of a graphic display.