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.

Heavy rainfall occurrence on April 14th, 2017 which followed by flood in Azarshahr and Ajabshir regions caused 48 deaths at East Azerbaijan province. Detecting synoptic mechanisms for such event was our main motivation for this study. In this regard, observational, upper atmospheric and SkewT data were used. First, spatial distribution of precipitation in the study area was plotted. Then, Geo-potential height, vorticity and omega, specific humidity, moisture transition, jet stream for upper level and Huff-Muller chart were analyzed for different atmosphere layers. Finally, some atmospheric stability indexes were surveyed by using SkewT charts. Results showed that, highest rainfall was occurred as a rain corridor between southwest of West Azerbaijan province and middle regions of Urmia Lake to the central regions of East Azerbaijan Province with 30 to 57 mm range. Synoptic maps showed that in this day simultaneous expansion of the ascending area of Mediterranean trough in mid atmospheric layers and the core of polar Jet stream in upper levels provided favorable conditions for unstable atmosphere on the northwest of Iran, so that the amount of omega was less than-0. 3 Pascal per second. Specific humidity maps indicate that, at the same time a significant moisture flux has flown from the Red Sea to the northwest of Iran. Therefore, the rapid conversion of atmospheric moisture into the rain in the ascending area of Mediterranean trough was the main cause of the heavy rainfall occurring on this day. This issue was proved by convergence moisture flux map and the Hoff-Mü ller graph. SkewT charts and instability indexes of Tabriz station also confirmed high amount of moisture and favourable ascending conditions in the atmosphere on April 14th.

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.

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.

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.

In synoptic meteorology, establishment of cold air masses at the middle and upper levels of the atmosphere is called cold air cell or cold air pool (Cold Pool). In this study the role of the cold pool in developing or intensifying the precipitation was examined by studying the synoptic maps for the period from 2007 to 2013 and 118 cases were identified. Synoptic maps, thermodynamic diagram (SkewT) and the distribution of rainfall on the selected days were investigated over East Azerbaijan province.The results showed that cold pool appears in three different synoptic patterns, temperature trough, closed cell or combination of trough and cell (at different levels). Although cold pool has been observed in warm season but the highest frequency appears in May. Investigation of rainfall recorded at the meteorological stations showed that 64% rainfall and 12.2% intense rainfall that has caused flood had been occurred in the establishment of cold pool. The results of thermodynamic diagrams' information indicated that although in most cases of atmospheric instabilities is confirmed by the indicator but in some cases weaknesses was observed in defining air instability which shows that dynamic condition (compared to the thermodynamic) is dominant during the establishment of cold pool. Finally, whenever the temperature difference in 850 and 500 level gets higher the probability of occurrence of intense rainfall, hail and flood are increased.

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.