فهرست مطالب neda abbasi

Network needs in today's era include comprehensive improvement of communication and connections with more bandwidth, minimum delay and high throughput. Software-defined networking is one of the most promising modes of future Internet development due to their centralized planning and management capabilities. The load balancing problem for distributed SDN controllers is one of the fundamental challenges of these networks, and a single centralized controller may cause reliability and scalability problems, and although several controllers can solve these problems, a flexibility mechanism is required for load balancing.Therefore, in this research, a load balancing mechanism is proposed based on the load information strategy, so that each controller in the system periodically reports its load information to other controllers, and the overload controllers of the plan, load infomation They do not collect all other controllers before local decisions are made, which in turn reduces controller resource consumption. A load balancing strategy is proposed in the proposed response time-based scheme for multiple SDN controllers, which takes into account the real-time response time characteristics that change with the controller load. Another key part of the proposed scheme is that all these things are done in the Ryu controller by choosing an appropriate response time threshold and processing multiple overload controllers simultaneously, which can solve the load balancing problem of the SDN control panel of the overload controller well. slow This model proposes to transfer the management of specific switches between controllers. In the simulation, the historical load and the future load of the switches were considered, and a switch migration algorithm with double weight was proposed, which led to a decrease in the frequency of switch migration. Experiments have proven that this scheme can quickly provide load balancing between controllers and reduce the number of switch migrations. The results showed that this design can lead to the migration of the overload controller and quickly reduce the workload of the overload controller. As a result, the proposed scheme can effectively achieve load balancing of multiple SDN controllers with high speed.

Drought stress increases production of secondary metabolites in wide ranges of plants and accumulation of these components usually occurs under stress. Secondary metabolites are natural compounds produced by plants that play different physiological roles in plants. Artemisinin is a sesquiterpene lactone, produces by some of Artemisia species. This secondary metabolite is one of the most important antimalarial drugs. This study was conducted to investigate the effect of drought stress on antioxidant enzymes activity and artimisinin content in Artemisia siberi. The experiment was carried out in a completely randomized design in greenhouse with four treatments of irrigation regime (control, 70, 50 and 30 percent of field capacity. intermittent drought stress was performed for 8 weeks. Drought stress caused increased the antioxidant activity of ascorbate peroxidase, peroxidase, superoxide dismutase and catalase. Highest activity for these enzymes was observed at 30% of field capacity. The amount of artemisinin were not significantly different between drought treatments and control. The results showed that drought stress does not always increase secondary metabolites and medicinal compounds such as artemisinin.

In this paper, we provide conditions on the smooth piecewise dynamical systems that guarantee the existence of Devaney chaos. In fact, we show that if f is a generalized semi-baker map with two branches and its derivative greater than or equal √2, then the dynamical system related to that is chaotic in the sense of Devaney. Such conditions on the dynamical systems with more than one discontinues point essentially does not satisfy this result.

Evaluating the Fuzzy and classical search engines' performance in Persian information retrieval to determine the false drop rate and select the best in retrieving the lowest duplicate records. In this applied research, the semi-experimental, evaluative and comparative methods are adopted. Research samples are selected according to purposeful sampling, based on the popularity of search engines. The data collection tool is a researcher-devised checklist with 20 questions. It is revealed that Google out performs Yahoo and Bing in both the fuzzy and classical evaluations. The obtained precision ratio of the fuzzy evaluation of search engines is greater than of the classical evaluation. In both evaluations, Google, Yahoo and Bing have the lowest rate of false drop, respectively. In the fuzzy evaluation, this false drop ratio is less than of the classical evaluation. Google has the lowest and Yahoo has the highest duplicate records' count. The obtained findings from the fuzzy and classical evaluation reveal that Fuzzy evaluation increases the precision rate and reduces false drop in search engines. Moreover the Fuzzy evaluation provides a more accurate and realistic precision and false drop rate by introducing a spectrum of relevance rate of retrieved records. It is recommended that researchers apply fuzzy evaluation when evaluating the search engines' performance. In general, Google has better performance than Bing and Yahoo based on three measured criteria. Consequently, users are advised to apply this search engine when searching for Persian information on the web to save time and money.

Primitive neuroectodermal tumors are fairly rare in uterus. A case of uterine body primitive neuroectodermal tumor in a 32-year-old Iranian woman is presented. The patient was admitted with abdominal pain and fever and underwent emergency exploratory surgery with total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection. Posterior wall of the uterus was necrotic and ruptured and a huge tumor disrupted the uterine body. The tumor was strongly positive for CD99, NSE, and chromogranin; No reaction was seen for CD10, CD45 and myogenin. To the best of our knowledge, this is the first report of an uterine body primitive neuroectodermal tumor and the second report of uterine primitive neuroectodermal tumor from Iran.