A multi-echelon supply chain design problem concerns the structure of the network and allocation of resources of the company to meet the demand forecast. This paper tries to design a multi-echelon supply chain network with five echelons including supplier, cross-dock, plant, distribution center and representative (customer). For this purpose, a mixed-integer mathematical model is developed to investigate the location of cross-docks, distribution centers, and also allocation between each pair of parties in order to minimize total cost of location and transportation. Due to the complexity of the model, a novel genetic algorithm is developed and applied on a real-world case study of Iran Khodro Company (IKCO) in Iran. Experimental results show the performance of the proposed Genetic Algorithm.

Background: Diabetes is a common disease. There are some reports that indicate higher prevalence of coronary artery disease (CAD) in diabetic than nondiabetic patients, thus evaluating CAD in such patients is of prime importance. Objectives:The aim of present study was to compare the extent of CAD in the diabetic and nondiabetic patients. Patients and Methods:In this case-control study 65 diabetic patients (case group) were compared with 145 nondiabetic patients (control group) based on severity of coronary artery stenosis at heart center of Mostafa Khomeini hospital in Tehran (Iran) in 2007. Both groups were matched for age, sex and risk factors. Coronary artery status was evaluated by coronary angiography followed by analysis of data using statistical methods. Results: Based on data found in our study, 93.8% of diabetic and 83.4% of nondiabetic patients were shown to suffer coronary artery stenosis. Severe involvement (grade 3VD) of coronary artery stenosis was observed in 44.6% and 28.8% of diabetic and nondiabetic patients, respectively. Statistically, a significant difference was found between two groups regarding the rate and severity of CAD (P < 0.05). The occurrence of coronary stenosis was higher in females among both groups yet the difference insignificant, statistically (P > 0.05). Conclusions: Our findings revealed that the severity of coronary artery stenosis is common in diabetic patients compared to nondiabetics. Early diagnosis and treatment of CAD in diabetic patients is recommended.

This paper presents a new structure as a simple method at two uncertainties (i.e., aleatory and epistemic) that result from variabilities inherent in nature and a lack of knowledge. Aleatory and epistemic uncertainties use the concept of the entropy and Dempster-Shafer (D-S) theory, respectively. Accordingly, we propose the generalized Shannon entropy in the D-S theory as a measure of uncertainty. This theory has been originated in the work of Dempster on the use of probabilities with upper and lower bounds. We describe the framework of our approach to assess upper and lower uncertainty bounds for each state of a system. In this process, the uncertainty bound is calculated with the generalized Shannon entropy in the D-S theory in different states of these systems. The probabilities of each state are interval values. In the current study, the effect of epistemic uncertainty is considered between events with respect to the non-probabilistic method (e.g., D-S theory) and the aleatory uncertainty is evaluated by using an entropy index over probability distributions through interval-valued bounds. Therefore, identification of total uncertainties shows the efficiency of uncertainty quantification.

No abstract