Covering models have found many applications in a wide variety of real-world problems; nevertheless, some assumptions of covering models are not realistic enough. Accordingly, a general approach would not be able to answer the needs of encountering varied aspects of real-world considerations. Assumptions like the unavailability of servers, uncertainty, and evaluating more factors at the same ti...

today business, are faced with global competition environment, and for be successful in this environment they always feel the need to radically change and creativity; and with entering spirituality into management and organizations, managers and leaders in organizations, 0should be required to deal with new phenomena. the role of spiritual leadership is to stimulating personnel by the use of sp...

The livestock sector globally is highly dynamic. In developing countries, it is evolving in response to rapidly increasing demand for livestock products. In developed countries, demand for livestock products is stagnating, while many production systems are increasing their efficiency and environmental sustainability. Historical changes in the demand for livestock products have been largely driv...

In applications there occur different forms of uncertainty. The twomost important types are randomness (stochastic variability) and imprecision(fuzziness). In modelling, the dominating concept to describe uncertainty isusing stochastic models which are based on probability. However, fuzzinessis not stochastic in nature and therefore it is not considered in probabilisticmodels.Since many years t...

Facility location decisions play a prominent role in strategic planning of many firms, companies and governmental organizations. Since in many real-world facility location problems, the data are subject to uncertainty, in this paper, we consider the P-center problem under uncertainty of demands. Using Bertsimas and Sim approach, we develop a robust model of the problem as an integer programming...

an enterprise resource planning (erp) software is needed for industries and companies that want to develop in future. many of the manufactures and companies have a problem with erp software selection. an inappropriate selection process can affect both the implementation and the performance of the company significantly. although several models are proposed to solve this problem many of them did n...

In the recent decades, rapid population growth has led to the significant increase in food demand. Food supply chain has always been one of the most important and challenging management issues. Product with short age, especially foodstuffs, is the most problematic challenges for supply chain management. These challenges are mainly due to the diversity in the number of these goods, the special n...