Mirjana Misita

New integrated approach to the problem of ranking and supplier selection under uncertainties

The problem of ranking and supplier selection in the uncertain environment is part of a purchasing plan and its relationship has a critical effect on the competitive advantage (high-quality products at lower cost with higher customer satisfaction) of each industrial organization. The considered problem can be stated as a multicriteria decision problem which includes both quantitative and qualitative criteria. The criteria present supplier performances which are defined by the purchasing Management Team depending on the size of industrial organizations and on production type. In this paper, the Management Team, using European Union (EU) recommendations, made a choice of criteria for supplier evaluation. The fuzzy rating weights of each pair of the considered criteria and uncertain criteria values are described by linguistic expressions which are modelled by triangular fuzzy numbers. The fuzzy extent approach for the synthetic extent values of the pairwise comparison for handling fuzzy analytic hierarchical process (AHP) is used to calculate the weight vector. The extension of the fuzzy technique for order preference by similarity to ideal solution (TOPSIS) is applied to rank the suppliers. The proposed model is illustrated by an example. It is shown that the developed model is highly suitable as a decision-making tool for reaching decisions about supplier selection.

A fuzzy model for assessing risk of occupational safety in the processing industry

Abstract Managing occupational safety in any kind of industry, especially in processing, is very important and complex. This paper develops a new method for occupational risk assessment in the presence of uncertainties. Uncertain values of hazardous factors and consequence frequencies are described with linguistic expressions defined by a safety management team. They are modeled with fuzzy sets. Consequence severities depend on current hazardous factors, and their values are calculated with the proposed procedure. The proposed model is tested with real-life data from fruit processing firms in Central Serbia.

A method to assess capacity utilization in short cycle functional layouts

Abstract The aim of this article is to indicate that methods of monitoring capacity utilization applied in the processing industry such as cement production can be used in the metalworking industry that has a high level of capacity utilization. The process approach to establishing the level of capacity utilization can be employed in conditions of balanced line production, or when there are components of large-scale production, as well as short production cycles. The results of the analysis indicate that when the level of capacity utilization is high, this variable can be observed per day as stochastic, while, per machine, it can be a random variable. In the metalworking industry it is possible to monitor a larger number of factors related to operating and not operating machines, whereas in the processing industry the factor of work is generally only a single-machining time and factors of not operating are connected only to breakdowns or regular maintenance. To monitor capacity utilization in the processing industry, it is possible to apply a work-sampling method as well as the continual streaming method. The possibility common for both industries is to represent the monitoring of capacity utilization over time and to test the mastering of that stochastic function via control limits that are optimal when defined by 2SD.

Fuzzy Multicriteria ABC Supplier Classification in Global Supply Chain

The determination of the optimal purchasing strategy in enterprise that is a part of global supply chain could be performed in two steps. In step one, a classification of potential suppliers is performed in order to determine the optimal portfolio of suppliers. This is delivered by using the fuzzy multicriteria proposed ABC classification method. Uncertainties in relative importance of criteria and their values are described by linguistic expressions. Modelling of linguistic expressions is based on the fuzzy sets theory. In the second step, ranking of optimal portfolio of suppliers is performed by using the modified ELECTRE method. The obtained results represent valuable input for determining the long time purchasing strategy and building partnership with the best suppliers. The developed two-step model is verified on real life data. The obtained results indicate good compliance with the opinions management in this type of industry. It is worth to mention that the proposed model can be easily extended and adopted to the analysis of other issues of management which could be applicable in different research areas.

Online monitoring and assessment of emerging risk in conventional industrial plants: possible way to implement integrated risk management approach and KPI’s

Existing methodologies and practices do not provide enough possibility for online monitoring and assessment of emerging risks occurring as a result of a change in technology, product, operating conditions, as well as in organization of activities in conventional industrial plants. Typical today’s off and online methods and corresponding software packages are used as risk assessment methods, while various risk aspects (such as: process risks, process equipment integrity risks, organizational risks, and health and environmental risks) are being assessed and treated independently. However, it is clear that risk assessment and making decisions in line with that has to be based on information collected from different (independent) sources in online mode. Also, the fact that additional risks in operations may occur due to unexpected changes in technology, accidents or unexpected process equipment degradation should be taken into account. When monitoring and process management systems are being designed and developed, only the process aspect and process risk are usually analyzed, while other risk aspects are not taken into account (like health and environmental risks). A new approach, to be presented in this paper, provides a possibility of online monitoring and assessment of risks (e.g. in petrochemical industry, power industry, etc.).

A novel approach to process improvement in small and medium manufacturing enterprises

Continuous business process improvement is a well-known strategy referred to as the “Japanese approach” to industrial production. Nowadays, it presents one of the basic requirements set by the ISO 9004:2000 standard. A new fuzzy model based on the Ishikawa diagram is proposed, whereby the rank of business losses of the main process at the manufacturing company level is determined, respecting the values of identified causes that lead to the formation of business losses, as well as their relative importance. In this article, it is assumed that the relative importance and values of causes are determined by descriptive linguistic expressions. The linguistic expressions are obtained by the fuzzy rating of a management team. The proposed algorithm determines the business losses with the highest possibility of occurrence and calculates the degrees of beliefs that some business losses are more likely to happen than the others. Real-life industrial data on small and medium companies operating in central Serbia and numerical examples are given to illustrate the method.

Universal equation for the relative change in profit of manufacturing company

In contemporary conditions of the companys business operations, where high dynamics of costs, sales volume and change of production programme is present, it is of crucial importance to investigate their effects on the change of profit. Starting from cost–volume–profit equation, the aim is to arrive at a universal equation that will simultaneously measure a relative change in profit for a number of products, not only under the influence of change in sales volume but also of other relevant variables, such as sales price, fixed and variable costs. The basic hypothesis is that it is possible to establish in a form of universal equation the dependence between the change in profit and change in influential variables. In this investigation, first it was observed the partial influence of some variables on the change in profit and their dependence was determined for a single product, and then for more than one product. Finally, by summing up all those effects, a universal equation of profit change was obtained. The derived universal equation for the relative change in profit along with simultaneous effects of several variables makes possible for the company management to more simply determine the profit for diverse conditions of business operations. The universal equation for the relative change in profit was applied in one company and the results obtained confirm its significance.

Identification of invariant factors that determine labour output on the production line

Abstract The efficiency of the production line system has been investigated by gaining a complex insight into a large number of variables affecting its functioning. The basic hypothesis of this paper concerns the existence of invariant factors that determine labour output on the production line. Applying factor analysis to constructed databases, the factors are extracted that confirm the basic hypothesis of this paper. In this research, multivariant analysis has been applied: cluster analysis to display the validity of ramification of the primary sample to small subgroups and factor analysis has been applied to the primary sample and the subgroups. The results of the application of the software package SPSS (Statistical Package for the Social Science) show that there are stable invariant factors that determine labour output on the production line. Invariant factors that determine labour output on the production line include: motivation of workers for production line work; elimination of adverse effects of work on the production line; rhythm of work; and psychophysical fatigue. The identified invariant factors provide a deeper insight into labour output as well as enabling the planning of activities that can improve production line work and make it more efficient.

A model for evaluation of customer satisfaction with banking service quality in an uncertain environment

The aim of this study was to propose a fuzzy decision-making model to evaluate customer satisfaction level which has a critical effect on the bank’s competitive advantage and its business. Value of customer satisfaction level can be determined by respecting all the factor values which are presented in this paper. The relative importance of indicators and their values are imprecise and uncertain variables which are modelled by using the fuzzy set theory. Relative importance of indicators under each identified customer satisfaction factor is stated by analogy to fuzzy analytic hierarchy process framework. Determining indicator values is stated as fuzzy group decision-making problem. The aggregated values of indicators are determined by using the fuzzy ordered weighted averaging operator. The overall index of customer satisfaction is determined by considering aggregated values of customer satisfaction factors. The level of customer satisfaction, which is closely linked with the quality of banking services, is determined by using fuzzy logic if–then rules. A case study with real-life data obtained from 22 enterprises is presented to verify the proposed method. It is shown that the proposed fuzzy model is a useful and effective assessment tool.

Development of a fuzzy logic-based inherent safety index for food industries

Inherent safety is a proactive approach for loss or elimination of hazard values and risk management. Expansion of safety relating to process and production in a supply chain in an uncertain environment has a critical effect on the competitive advantage of each food industrial organization. In this article, the fuzzy rating weights of each pair of the considered hazards and uncertain hazard values are described by linguistic expressions modelled by triangular fuzzy numbers. The fuzzy extent approach for the synthetic extent values of the pairwise comparison for handling fuzzy analytic hierarchical process is used to calculate the weight vector. The proposed fuzzy model is arranged in a hierarchical structure, so that the output of one interference system is used as an input for the second interference step. In the first of interference steps, the total hazard value for each identified process is calculated using the fuzzy algebra rules. In the second interference step, the inherent safety index for each process is determined on the basis of total hazard value, using the IF–THEN fuzzy logic rules. It is shown that the proposed fuzzy model is highly suitable as a decision making tool for making decisions about the inherent safety index of food industrial processes.