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%.

Population Dynamics and spatial Distribution of two harmful species of Thysanoptera prevalent on cereal crops (Thrips tabaci Lindman, 1888 and Haplothrips tritici Kurdjomove, 1912), were investigated during 2009-2011. Weekly sampling was carried out in a one hectar of wheat field in Ramin University of Khuzestan, South-West of Ahvaz. Spatial Distribution of immature as well as adults of either species was investigated through Taylor’s power law and Iwao’s patchiness regression methods. The results revealed that the population peak for either species occurs in late March and on the first to middle of April respectively for adults and for larvae. Results of correlation between population Dynamics (larval and adult stages) and the factors temperature and precipitation revealed that thereis positive vs negative correlations between population fluctuation and the factors of temperature vs humidity. An investigation of the spatial Distribution through Taylor’s power law and Iwao’s patchiness regression method indicated that larval stage and total stages in both species are clumped. Based upon R2 and F of regression analysis, Iwaos patchiness provided a more adequate description of spatial Distribution than Taylor’s power law for either of the species. Because the seasonal peak in these two species' density corresponded with the period of peak bloom, thus, in order to study the population Dynamics, the earing stage is the most suitable for sampling the thrips on wheat.

Electricity Distribution Companies are supposed to lower undelivered electricity and supply electricity reliably. In this paper, we analyse the factors affecting undelivered electricity using system Dynamics approach, taking into consideration the case of North-Kerman Electricity Distribution Company. According to the results, undelivered electricity could have been decreased from 77.8 MWh to 55.1 MWh in 2014 if necessary corrective policies would have been implemented. Network standardization, staff training and instructing rules and protocols would reduce unplanned outages. Planned outages should be schedulled for low- load seasons and hours and frequent outages in a certain area should be avoided.

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.

Failure of dotcom companies, after 1990s’ rapid boost, raise many questions about e-Business solutions in commercial performance. The aim of this paper is to investigate the role of intermediaries in the new business environment. It is suggested that in the traditional trade models, intermediaries have a hidden role while just analyzing goods and money data and transferring the knowledge to both parties. Electronic business suggests a direct producer-consumer relationship. This can cause an immediate transfer of unfiltered data between both ends of the chain. We show here that intermediaries can manage the knowledge and help both sides to decide efficiently the level of production and transaction.

Environmental factors mainly temperature are believed to determine the Distribution and population Dynamics of Fusarium species in a natural ecosystem. Species may be restricted in their Distribution by adaptation to specific sets of soil environmental conditions. Population Dynamics of five Fusarium species representative of different climatic conditions were studied at three levels of temperature (13-18 / 19-24 / 25-30°C) and constant water potential (field capacity). Temperature had a significant influence on the population level of all test Fusarium species. Fusarium sambucinum showed noticeable reduction of population at warm temperatures. The population of F. solani and F. compaction were higher at high temperatures. The population of cosmopolitan species, F. equiseli showed little change at all experimental conditions, Fusarium acuminalum did not compete well with other species in this experiment, its population being low at all treatments.

To study the diversity and structure of zooplankton, samples were collected at two commercial regions, Nowshar and Anzali harbors at the depths of 5, 10, 15 and 20 meters in the southern Caspian Sea in 2011. A total of 10 species formed zooplankton populations included of copepods (2 species), cladocera (1 species), balanidae (1 species), rotatoria (2 species), protozoa (1 species) and 3 temporary plankton species (meroplankton). The study showed that the average annual population density and biomass of zooplankton were 3120±552 in d/m3 and 22.5±5.0 mg/m3, respectively. Maximum average of annual zooplankton abundance and biomass were belonged to copepods with 998±60 in d/m3 and 4.1±0.3 mg/m3. Quarterly seasonal review (temporal Distribution)of zooplankton abundance and biomass showed that most with the spring season of an average density of 3767±770 in d/m3 and 32.9±7.4 mg/m3, respectively. Seasonal Distribution of zooplankton showed that crustacea (included copepods, cladocerans and balanidae) consisted 70.5% of population and 36.4% of biomass.