---

Here, we investigate the classical p-median location problem on a network in which the vertex weights and the distances between vertices are uncertain. We propose a programming model for the uncertain p-median location problem with tail value at risk objective. Then, we show that it is NP-hard. Therefore, a novel hybrid modified binary particle swarm optimization algorithm is presented to obtain the approximate optimal solution of the proposed model. The algorithm contains the tail value at risk simulation and the expected value simulation. Finally, by computational experiments, the algorithm is illustrated to be efficient.

---

The present study aims at designing a cold multi-cycle supply chain based on a multi cross-dock system taking into account uncertainty. In the first step, we identified the factors and variables of the model. In the second, by selecting the study period through designing data collection forms and using the documents reviewing methodologies, the raw data required to measure the final indicators were collected and processed in the project model. Then, they were analyzed considering the research topic and using the techniques of genetic algorithm and particle swarm optimization. The primary objective function is minimizing the cost of transportation and warehousing throughout the supply chain, the second minimizing the total operation time and the number of vehicles within the supply chain, and the third maximizing the product freshness time. Also meta-heuristic optimization methods (strongly adjustable) were adopted to deal with the travel time of suburban vehicles. We also provide an example of the performance of optimization models for a small-sized sample. The computational results showed that longer travel time and further distance do not necessarily increase costs. In fact, it is possible to distribute the products with the right number of trucks at an optimal cost at the right time.

---

The purpose of the present study was to determine the effect of education using mathematical games on learning and retention of third grade elementary students. This research in terms of purpose was conducted as an applied research. Also in terms of implementation and data collection method, the quasi-experimental method and pre-test-post-test design with a control group was used. The statistical population of the present study included all 6,500 female third grade elementary school students in District 1 of Mashhad- Iran. The sampling method in this study was in convenience form that included 60 students and were selected through convenience sampling method, thus two classes with 30 female students for each classroom were selected among the elementary girls' schools in District 1 of Mashhad- Iran. In order to collect data, two researcher-made tests of learning and retention were used, the validity of which was confirmed by experts and its reliability was calculated based on Cronbach's alpha equal to 0.81 and 0.83, respectively. Multivariate analysis of covariance (MANCOVA) was used in order to test the hypotheses inferential analysis. The results of data analysis showed that math games are effective on students math both learning and retention (P <0.01). Therefore, it can be concluded that education using math games is effective and has increased students' learning and retention.
 

---

In an uncapacitated facility location problem, the aim is to find the best locations for facilities on a specific network in order to service the existing clients at the maximum total profit or minimum cost. In this paper, we investigate the uncapacitated facility location problem where the profits of the demands and the opening costs of the facilities are uncertain values. We first present the belief degree-constrained, expected value and tail value at risk programming models of the problem under investigation. Then, we apply the concepts of the uncertainty theory to transform these uncertain programs into the corresponding deterministic optimization models. The efficient algorithms
are provided for deriving the optimal solutions the problem under investigation.