in recent years, the problem of selecting and evaluating the suppliers in supply chain management has aroused considerable interest in business firms. owing to the development of information systems, reaching an appropriate decision for adopting discrete methods is a need. the researchers intend to present a new model in this paper as a contributing factor in the grey environment in which the r...

some incidents in urban railway systems affect the function of the subway’s company adversely and they could disorder the services. these events may inflict irreparable damage to passengers, employees and equipment. by recognizing the hazards existing in this type of transportation system and evaluating and prioritizing risks, we can perform appropriate actions to reduce the probability and sev...

The theory of grey system is used when sufficient information of the community under study is not in hand. The grey forecast model is proper when the information variety is fix and certain. Grey model can apply some additional computations to improve forecasting activities when data is insufficient. Through using improved grey model, the assessment error decreases significantly. This study made...

this study focused on the optimization of al—mg to cuzn34 friction stir lap welding (fslw) process for optimal combination of rotational and traverse speeds in order to yield favorable fracture load using grey relational analysis (gra). first, the degree of freedom was calculated for the system. then, the experiments based on the target values and number of considered levels, corresponding orth...

The purpose of this paper is describes the use of grey pridiction in linear programming problems. Some definitions and concepts of grey system theory are introduced and then, we introduced GM(1,1) and fractional order accumulation into grey model. Due to the fluctuation of prices and the lack of certainty data in the market, optimal production was calculated to optimize the profit from sales us...

This study focused on the optimization of Al—Mg to CuZn34 friction stir lap welding (FSLW) process for optimal combination of rotational and traverse speeds in order to yield favorable fracture load using Grey relational analysis (GRA). First, the degree of freedom was calculated for the system. Then, the experiments based on the target values and number of considered levels, corresponding orth...

abstract this author introduces the concept of stepwise strategy approach (ssa) for dealing with a number of problems arises in the current age of technology. this new idea is combined with the knowledge of grey theory for adding flexibility to decision making process. grey theory is useful for grasping the ambiguity exists in the utilized information and the fuzziness appears in the human judg...

nowadays, in order to reach minimum production cost in machining operations, various optimization methods have been proposed. since turning operation has different parameters affecting the workpiece quality, it was selected as a complicated manufacturing method in this paper. to reach sufficient quality, all influencing parameters such as cutting speed, federate, depth of cut and tool rake angl...

Grey System theory was initiated in 1982 [7]. As far as information is concerned, the systems which lack information, such as structure message, operation mechanism and behaviour document, are referred to as Grey Systems. For example, the human body, agriculture, economy, etc., are Grey Systems. Usually, on the grounds of existing grey relations, grey elements, grey numbers (denoted by 8 ) one ...

Energy simulation is a vital part of energy policy of a country, especially for a developing country like China where energy consumption is growing very rapidly. The present study has been conducted to simulate the total primary energy consumption in residential sector in rural areas in Chongqing by using macro and micro drivers including population size, number of households, persons per house...