One of the obvious reasons for most disorders in network service provisioning is network path congestion. Congestion avoidance in today's networks is too costly and sometimes impossible. With the introduction of SDN, centralizing the equipment's control plane has become possible. This paper presents an enhanced method named ESV-DBRA to avoid congestion in multi-tenant SDN networks. At first, ESV-DBRA monitors the traffic load and delay of all network paths for each tenant individually. Then, by merging the parameters obtained from the monitoring, the Service Level Agreements (SLA), and a novel proposed cost function, it calculates the cost of the network paths per tenant. As a result, traffic for each tenant is routed through the path/paths at the lowest possible cost from the tenant's perspective. Next, the bandwidth quotas will be calculated and assigned to the tenants over their optimal routes. Afterward, whenever congestion is likely to occur in a path, ESV-DBRA automatically changes the route or bandwidth of the tenants' traffic related to this path to avoid congestion. Related algorithms are also proposed.Eventually, simulations show that the proposed method effectively increases bandwidth utilization by 10.76%.

Different types of contact, including contact between node pairs, any-contact of nodes, and contacts of the entire network, are used to characterize social relations in mobile social networks. Different modes of routing, from the point of view of message delivery semantics, encompass unicasting, multicasting, any-casting, and broadcasting. Studies have shown that using probability Distribution functions of contact data, which is mainly assumed to be homogeneous for nodes, improves the performance of these networks. However, there exists an important challenge in studies on Distributions. A lot of works apply the Distribution of one type of contact to other types. Hence in routing applications, it causes to use of the Distribution of one type of contact for any mode of routing. This study provides a complete solution to model each type of homogeneous contact data Distribution and to use them in different modes of routing. We propose a routing algorithm that uses this new model. Results show that our solution improves the average latency of comparing methods Epidemic, TCCB, and DR about 3.5-times, 30%, and 45%, respectively. It achieves a delivery rate of about 5% and 6%, and average latency about 6% and 8% better than that of DR and TCCB, respectively.

در این مقاله مولف بر آنست که تأثیر "یارانه ها و نظام توزیع آن" بر مهاجرتهای روستایی و روند شهرنشینی در ایران را مورد بررسی قرار دهد. موضوعی که پیش از این ادبیات جغرافیایی کشور کمتر از این منظر به آن پرداخته است. به این منظور ابتدا "ساختار و بافت یارانه ها" در دو مقطع قبل و بعد از انقلاب اسلامی مقایسه شده است. سپس نحوه "توزیع بخشی و جغرافیایی" یارانه ها توسط دولت ارزیابی شده است و نهایتا پیامدهای فضایی و جغرافیایی ناشی از نظام فعلی توزیع یارانه ها مورد تجزیه و تحلیل قرار گرفته است. یافته های تحقیق این اجازه را به ما می دهد که از "نظام توزیع یارانه ها" به عنوان یکی از مصادیق اعتبار و کاربرد پذیری نظریه «دولت و شهرنشینی» (رهنمایی، 1373،صص17-12) در تبیین مسائل شهرنشینی در ایران یاد کنیم.  

1این مطالعه مؤلفه های انگیزشی را در سیستم های رتبه بندی معلمان و تأثیر آن ها بر انگیزۀ رشد حرفه ای بررسی می کند. با استفاده از یک رویکرد مرور سیستماتیک، متون مربوط به سیستم های رتبه بندی معلمان، انگیزش و ادبیات توسعه حرفه ای را بررسی می کند. با بررسی متون مختلف و یافته های پژوهشی در مورد انگیزش معلم، عوامل مؤثر بر رتبه بندی معلمان بر اساس شایستگی های عمومی، تخصصی و حرفه ای و همچنین تجربه شناسایی می شوند. این مطالعه با ترسیم موازی با نظریۀ انگیزشی هرزبرگ، توصیه هایی را برای تقویت انگیزه معلم و رضایت شغلی از طریق بهبود در سیستم رتبه بندی ارائه می دهد.

Monitoring and evaluation of transformers are essential to prevent their insulation failure. In this paper, the use of 2-furan-carboxaldehyde (2-FAL) and methanol (MeOH) concentrations as the main products of paper insulation degradation, and insulation condition markers, has been studied. In order to study the degradation process and production of degradation products, the thermal aging process of the transformer insulation System was implemented in laboratory conditions. The results of laboratory studies show that in the early stages of degradation the amount of MeOH is significant compared to 2-FAL. Also, the estimation of the degree of polymerization (DP) in the early stages of degradation (DP>800) through MeOH concentration and with decreasing DP (DP <800) through 2-FAL concentration is closer to the real value. The results of studies performed on 35 Distribution transformers confirm the production of significant amounts of MeOH in the early stages of degradation. Also, the estimated DP values for the studied transformers were obtained through 2-FAL and MeOH concentration. The results show that estimating the amount of DP through MeOH concentration is associated with a probability of error of about 9% compared to estimating DP through 2-FAL concentration.