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.

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.

The presence of 2 species of genus Codonopsis in the flora of Middle Asia was traced. Description of a new species found in the western part of Uzbekistan is given. Furkat O. Khassanov (correspondence), Ulugbek H. Kodyrov, Central Herbarium, Institute of the Gene Pool of Plants and Animals of Academy of Sciences of the Republic of Uzbekistan, st. Durmon yuli 32, 100125, Т ashkent, Uzbekistan. Anar Myrzagaliyeva The Republic of Kazakhstan, 070019, Ust-Kamenogorsk, 55, Kazakhstan st., East-Kazakhstan State University.

Cheilanthes persica (Bory) Mett. ex Kuhn. (Pteridaceae) is one of the resurrection ferns that fully dries during drought stress and after re-watering will be revived. Fresh material obtained from Kermanshah province, west of Iran (Tagh-e-bostan) and cultured in growth chamber and its developmental stages and life cycle were examined. The spore morphology was studied. The spore had tetrahedral tetrad with discontinuous microreticulate ornamentation.

Purpose: Application of heavy forces to maxillary dentition during treatment with headgear, induces high concentration of stresses in periodontal tissue. Quantification of this stress is of great concern in orthodontics. This study was designed to investigate the quantity and quality of stress response in the PDL of maxillary first molar which was subjected to high pull headgear traction using Finite Element method.Methods and Material: In an experimental study, a three-dimensional finite element model of maxillary dentition, consisting of 17096 elements and 23013 nodes, was developed based on a young human skull. The forces were applied to the maxillary first molar in the stabilized Arch by means of a rectangular full size arch wire in (022) slot bracket. Mechanical properties of this model were based on previous studies. A 350 gram force was used for high pull headgear to affect the dentition (+30 degree) and stress distribution was investigated in buccal, palatal, mesial and distal side and in cervical, middle, apical sections of the PDL. The quantity of stresses were expressed as principal stresses (1,2,3), while the negative and positive signs indicated compressive and tensile stresses.Results: The buccal surface of PDL of mesiobuccal root and the buccal, palatal and distal surface in cervical region of PDL of distobuccal root and the distal surface of the PDL of palatal root had received a great deal of stresses, in addition, the over all stress distribution in roots of molar had intrusive nature.Conclusion: The extension of high stress concentration areas observed after using high pull headgear is limited to some root surfaces specially the distobuccal root.

Background: Previous studies on the survival of continuous ambulatory peritoneal dialysis (CAPD) patients have been done using the Cox model. This model requires establishing the basic assumption of proportional hazard (PH) and not establishing it leads to misleading inferences. Alternatively, if the time-to-event distribution is known, accelerated failure time models can be developed in such a way that no PH assumption is required. The purpose of this study is to compare the survival of CAPD patients in two hypertensive and non-hypertensive groups in the condition of not establishing the PH assumption. Materials and Methods: In this retrospective cohort study, 1, 400 patients who were referred to dialysis centers from different parts of Iran between 1995 and 2010 were included. The loglogistic, lognormal, and generalized gamma parametric frailty models were compared using Stata 17 software. Results: The five-year survival rate was 54%. The median survival time for the hypertensive group was lower than for others. Age, body mass index, fast blood sugar, potassium, and creatinine were higher in hypertensive patients. In the early months of dialysis, the risk of death is high and decreases with time. Univariate results revealed that hypertension leads to acceleration of death (HR = 0. 79,95% CI (0. 64, 0. 98)). Multivariate analysis showed that increasing age (HR = 0. 97,95% CI (0. 96, 0. 98)), comorbidity (HR = 0. 71,95% CI (0. 55, 0. 91)) and high blood sugar (HR = 0. 997,95% CI (0. 999)) accelerated the risk of death. An increase in serum albumin (HR = 1. 27,95% CI (1. 04, 1. 57)) leads to a delay in death event. Conclusions: Parametric models (especially the loglogistic model) are appropriate in evaluating factors affecting the survival of CAPD patients.

Myosotis diminuta Grau (Boraginaceae) is recorded for the first time for the flora of Iran. It was rediscovered in 2013 in Zanjan Province, NW of Iran, in a wetland habitat far from its previously known habitat after not being documented for more than 100 years. A detailed taxonomic description and photographs are provided to facilitate its identification in the field. Also diagnostic characters to define Myosotis diminuta from its close relatives are provided.