Research Topics in Prof. Nishi’s Group( BLOG )

Japanese version is here.

Supply Chain Management

With the globalization of business structure in many industries, the integration of business processes with different company is driven by the various requirements from customers. The challenges posed by the integration and expansion are on collaborative decision making regarding to global supply chain management.  Supply chain management is to provide effective solution technique for decision making across the supply chain consisting of material procurement, production, distribution and retailers to reduce inventory and total costs in order to maximize the total satisfaction from customers with consideration of environmental burden. For one company or one factory as a business unit, the supply chain management is defined as a cross-function approach to manage the resource (money, manpower, energy etc.) from initial point to the point of consumption, reuse, and recycling. A basic question regarding to the supply chain management is how to integrate decision making from the shop floor level (operational level) to the mid-term planning (tactical level), and the business management (strategic level) with different time scale. In our laboratory, the coordination of manufacturing planning for multiple companies, inventory cotrol under demand uncertainty, integration of logistics and manufacturing, contract decision based on detailed production planning, and multi-agent decision support for collaborative supply chain network are tackled.

 Keywords：　business managenent, revenue planning, economics, resource planning, contract decision, logistics, distribution, game theory, environment, simultaneous optimization, decision under uncertainty, environmental burden

Scheduling

Scheduling problem asks the sequence of tasks and the allocation of resource to task over time periods and its goal is to optimize the objective function under constraints such as technical order relationship/resource constraints. Scheduling has an important role in the most of manufacturing and production systems as well as in most of information processing environments. It is also important in university timetabling, crew scheduling, transportation, distribution and in other types of service industries. In our laboratory, effective algorithms and solution techniques are studied. The application to international transportation problems, scheduling in semiconductor manufacturing, and scheduling in public transport are also undertaken.

 Keywords：　public transport, railway scheduling, airline scheduling, ship scheduling, semiconductor manufacturing, timetabling, crew scheduling, human interface, production scheduling, real-time scheduling

Design and Control of Transportation Systems

Automated Guided Vehicles (AGVs) are used for transportation systems in semiconductor fabrication, container terminals, and recent automated transportation systems in hospitals. For automated systems in physical distribution, automated storage and retrieval systems (ASRS), conveyor systems, forklifts, warehouse, and cross-docking as truck terminal are widely used in many industry as material handling systems in recent automated manufacturing systems. As you know,  a numerous number of robots are collaboratively working in the automated systems. The systematic modeling, optimal operation, control and design of transporatation systems are studied. The integrated optimization of manufacturing and transportation is one of the topics in this study.

 Keywords：　material handling systems, transportation, automated guided vehicles, automated storage and retrieval systems, automated transport systems in hospitals, elevator, automation

Multiple Mobile Robot Control

We study multiple mobile robot motion planning and control for collision avoidance, deadlock avoidance. System is deadlocked when the system is stopped because two or more than two processes wait the completion of the other process and never return to its normal state. This situation occurs not only in the production systems but also in conflicts in social systems. Deadlock resolution is one of critical problems which should be resolved. We study the methodology and algorithm by multi-agent approach to detect and predict deadlock and avoid it by each local intelligent agent by communicating with other processes.

 Keywords：　robotics, motion planning, path planning, autonomous decentralized systems, intelligent systems, cooperative motion planning, collision avoidance

Optimization of Discrete Event Systems

The systems described by a discrete set and state transition driven by events are called as discrete event systems (DES). Petri Nets and automata is used as the formal description language of discrete event systems. In our study, discrete event system model is used to represent a wide variety of scheduling problems. General scheduling solver is developed by using the formal language.

 Keywords：　computer science, formal language, language theory, discrete information processing, automata, Petri nets, computer, simulation