Yasufumi Kume

Goal programming problems with interval coefficients and target intervals

Abstract In conventional goal programming, the coefficients of objective functions and constraints, and target values are determined as crisp values. However, it is not frequent that the coefficients and the target values are known precisely. In such cases, the coefficients and target values should be represented by intervals reflecting the imprecision. This paper treats goal programming problems in which coefficients and target values are given the intervals. It is shown that four formulations of the problems can be considered. The properties of the four formulated problems are investigated. An example is given to demonstrate the differences between the four formulations.

A solution algorithm for fuzzy linear programming with piecewise linear membership functions

Abstract This paper deals with the fuzzy linear program with continuous piecewise linear membership functions. A fuzzy linear program with piecewise linear membership functions has been considered by Hannan and Nakamura. Hannans method can solve the problems only when all membership functions are concave in the range (0, 1) and Nakamuras method needs to use the linear programming technique repetitionally. We propose a technique to solve the problem using a standard linear programming when membership functions are strictly quasiconcave and the minimum operator is adopted for aggregating fuzzy goals. The repetitional use of linear programming technique is not required in our method.

Modality constrained programming problems: a unified approach to fuzzy mathematical programming problems in the setting of possibility theory

Abstract In this paper, fuzzy mathematical programming problems are formulated based on the idea analogous with the chance constrained programming problem. The difference in meaning between the ambiguity of the coefficients and that of the decision makers preference is emphasized. The constraints with fuzzy coefficients are treated as the restriction that should be satisfied properly rather than perfectly. The objective functions with fuzzy coefficients are treated variously depending on the interpretations, i.e., the optimization of the modalities, the optimization of the fractile, the minimization of the ambiguity, and so forth. The deterministic equivalent constraints and the deterministic equivalent problems are shown when the constraints and the objective functions are linear. A numerical example is given to illustrate the proposed formulations.

The usefulness of possibilistic programming in production planning problems

Abstract In this paper, we discuss the merits of possibilistic programming approach to production planning problems. First we consider a simple production planning problem with ambiguous data and decision-makers vague aspirations. The drawback of the conventional approach is mentioned and a possibilistic programming approach is introduced in order to tackle such kinds of problems. Applying a possibilistic programming based on possibility and necessity measures, the production planning problem is solved. In order to demonstrate the significance of taking the ambiguity of data into consideration, the solution is compared with the other solutions obtained to solve a flexible programming problem and a goal programming problem. In consequence, the merits of possibilistic programming approaches are emphasized.

Relationships between modality constrained programming problems and various fuzzy mathematical programming problems

Abstract In this paper, we focus on the relationships between modality constrained programming problems and various fuzzy mathematical programming problems, i.e., flexible programming problem, fuzzy goal programming problem and fuzzy mathematical programming problems proposed by Orlovski, Tanaka et al., Inuiguchi et al., Dubois and Sakawa et al. Fuzzy mathematical programming problems discussed in this paper can be interpreted in the framework of modality constrained programming problems. Thus, modality constrained programming problems can be regarded as a base model for unifying various fuzzy mathematical programming problems.

Power spectral analysis of heart rate variability in type A females during a psychomotor task

This study investigated changes in autonomic nervous activities due to psychological stress in Type A females. Eight Type A and eight Type B females performed a psychomotor task for 30 minutes. Power spectral analysis of heart rate variability (HRV) was used to examine the autonomic nervous activities. Results showed the low frequency (LF) component and LF/HF ratio in Type A females increased after the onset of the task. There were no significant differences in task performance between Type A and Type B females. The subjective mental workload increased gradually in Type A females during the tasks, whereas in Type B females this parameter did not change in a consistent manner. The results suggest that the sympathetic nervous system in Type A females was more stimulated by the task and Type A females felt a greater subjective mental workload than did Type B females.

Some properties of extended fuzzy preference relations using modalities

Abstract A fuzzy preference relation is extended to six kinds of relations between fuzzy sets. The properties of the six extended relations are investigated. Especially, a sufficient condition for reducing the extended relations to four kinds is discussed when fuzzy sets are bounded and normal, and some examples are given to illustrate it. Further, a sufficient condition for the extended negative relations to coincide with the extended inverse relations is described.

NECESSITY MEASURES DEFINED BY LEVEL SET INCLUSIONS: NINE KINDS OF NECESSITY MEASURES AND THEIR PROPERTIES

In this paper, nine necessity measures are proposed and their properties are investigated. Three classes of necessity measures are defined. Considering their meanings, several kinds of necessity measures are proposed in each class. The representations of the proposed necessity measures using implication functions are given. The properties of the proposed necessity measures are discussed and their relationships among them are clarified.

Biomechanical study on the postures in manual lifting tasks using cusp surface analysis

This study describes applications of the stochastic catastrophe theory in modeling low back injury in view of the elementary cusp catastrophe. It was proposed that low back injury due to manual load lifting should be considered as a discontinuous phenomenon. The main objective of this study is to develop a cusp catastrophe and to model the risk of low back injury quantitatively. The bimodality in the bifurcation set of stochastic catastrophe model was shown using biomechanical data. The relationship among independent variables and a dependent variable under a certain condition was clarified.

Skill transfer from expert to novice: instruction manuals made by means of groupware

Modern manufacturing industry changes dramatically following the fast progress of mechanical improvement and informatics development. Young people focus on learning new techniques in order to catch up the fast progress. Traditional industrial skills are missing step by step that will be a problem for modern industrial manufactures. The technological generation gap also causes damage in manufacturing industry. Elder experts who accumulated many traditional industrial skills faced the problems of retirement and strict competition. Young novices receive modern industry technique trainings, but still require traditional skill to maintain the industrial manufacture. The skill transmission from elder expert to young novice is known as an important course. In Japan, industry pays a lot of concern at the decline in mastery of skills technology. Based on the importance and difficulties of skill transmissions, an idea model was searched and established in this study. We choice screw manufacture as a representative industry in this study because screw manufacture required traditional skills and modern techniques. A manual introducing traditional skill and integrating computer science could transmit technologies smoothly from elder expert to young novice. Computer science here is used to link generation gap, to introduce traditional skill delicately in order to keep all the detail tricks and lively in order to be accepted by novice. The transmission efficiency and efficacy both will be considered.