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%.

In this article author would try to define effects of subside on rural migration and urbanization. Ti seems that Iranian geographicaUiterature merelyhave been looks at subside as a causal factor in this phenomenon. First of all. the stracture of subside will be compare before and after the revolution. then its geographical and sectoral destribiution will be investigateand finallya discussion will be made on geographical and spatial outcome. As a result of this investigation patern of subside destribution could be refer as a practical example of "State and urbanization" theory (Rahemai,M.1994)in development of urbanization.

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.

ObjectivePRIMARY central nervous SYSTEM lymphoma (PCNSL) is an extremely rare condition in childhood. We report the first case of PCNSL in a child in Iran.Clinical presentationA nine-year-old boy was referred to Mofid Hospital with the history of headache of four months and seizure of 2 months duration. Magnetic resonance imaging of the brain revealed a hyper-intense lesion in left fronto-parietal area with secondary satellite lesions.Biopsy of the brain mass was performed. Pathologic findings showed brain lymphoma and immunohistochemistry confirmed this diagnosis. The treatment started with intrathecal and SYSTEMic chemotherapy in combination with radiotherapy.