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Many recent probability distributions are introduced by compounding the well-known continuous distributions  with the power series distribution.   In this paper, we provide a general closed-form expression  for the cumulative distribution function of this class. Then, we introduce  a new four parameter lifetime distribution called  Zhang-power series (ZPS) distribution. This distribution is very useful in the lifetime, reliability and extreme-value data analysis. The distribution properties including survival function, hazard function and limiting behavior of the probability density  and hazard functions are studied. The method of maximum likelihood estimation is used to estimate the model parameters. Applications to real data sets are given to show the flexibility and potentiality of the proposed model.

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%.

The present research aims to find a precise method for the wu-zhang system on scattered long waves, which can be a positive step for physical science in dealing with the structure of scattered waves and provide 3D diagrams for further studies of other sciences.

In many of developed and developing countries, nowadays, B. O. T conctract is a way in which government performe their essential project as transport one through observing investment from privait firms, instead these privit firms earn the main investment as well as their profit from user fees. For many BOT transport projects, the government imposes service level requirement on the private firm so that project capacity and stochastic demand can be better matched. Service level can be defined as the probability of project capacity satisfying uncertain demand. Due to high risck of this kind of contaracts, the governmet, for many B. O. T transport projects, imposes service level requirement on the private firm so that project capacity and stochastic demand can be better matched. Service level is defined as the probability of project capacity satisfying uncertain demand. In this research as a determination optimal service level on B. O. T transport project contract based on Zhang model (Case Study: Tehran Fleet Electronic Ticket Contract) is conducted. The results suggest that the presence of service level requirement improves B. O. T h user fee and project capacity while decreases firm profit. Moreover, two formulas, to predict the servive level based on ontherrequlations, have been generated from the data of the project, using Gene EXperssion Programming through MATAL. The correlation coefficients of proposed relationship were relatively high, indicating the dependence of service level to project capacity, user fee, privit firm’ s prfite, the number of users, demand uncertainty.

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.

A considerable part of our knowledge about Iran and its relations with other neighboring civilizations has been based on Greek and Roman texts and sources, some of which have been translated into Persian with acceptable quality. However, there is important information about ancient Iran in the historical texts and archaeological findings discovered in the Far East, especially China. A small number of them have been translated into Persian, which contains errors. Therefore, considering the importance of historical texts and archeological data related to Iran in China, the present article intends to first examine the works related to ‘, Iranian-Chinese Relations’, , in order to pathologize the Persian translations of these texts and research on Iran-China relations. Then, it seeks to criticize the part related to ancient Iran in the book “, Ancient Texts on China-Iran Relations”, . The most important outcome of this study is the weakness of translators and editors in translating Chinese texts and research into Persian, which in some cases, these weaknesses are the result of important mistakes of the authors of the research in the West.

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.

In this research we investigate the relationship between the accounting variables and stock returns based on the equity value model of Zhang. The aim of the paper is to show that stock returns is a function of earning yield, equity capital investment, changes in profitability, growth opportunities and discount rates. Based on the literature review five hypotheses has been considered and analyzed by simple and multiple regression methods during 2001-2010 in Tehran Stock Exchange (TSE).Empirical results do not confirm the predicted roles of all identified factors. Only there is a direct relation between earning yield and stock returns also there is an inverse relation between changes in discount rates and stock returns.