Session Initiation Protocol Attacks and Challenges

In recent years, Session Initiation Protocol (SIP) has become widely used in current internet protocols. It is a text-based protocol much like Hyper Text Transport Protocol (HTTP) and Simple Mail Transport Protocol (SMTP). SIP is a strong enough signaling protocol on the internet for establishing, maintaining, and terminating session. In this paper the areas of security and attacks in SIP are discussed. We consider attacks from diverse related perspectives. The authentication schemes are compared, the representative existing solutions are highlighted, and several remaining research challenges are identified. Finally, the taxonomy of SIP threat will be presented

A Taxonomy for Congestion Control Algorithms in Vehicular Ad Hoc Networks

One of the main criteria in Vehicular Ad hoc Networks (VANETs) that has attracted the researchers' consideration is congestion control. Accordingly, many algorithms have been proposed to alleviate the congestion problem, although it is hard to find an appropriate algorithm for applications and safety messages among them. Safety messages encompass beacons and event-driven messages. Delay and reliability are essential requirements for event-driven messages. In crowded networks where beacon messages are broadcasted at a high number of frequencies by many vehicles, the Control Channel (CCH), which used for beacons sending, will be easily congested. On the other hand, to guarantee the reliability and timely delivery of event-driven messages, having a congestion free control channel is a necessity. Thus, consideration of this study is given to find a solution for the congestion problem in VANETs by taking a comprehensive look at the existent congestion control algorithms. In addition, the taxonomy for congestion control algorithms in VANETs is presented based on three classes, namely, proactive, reactive and hybrid. Finally, we have found the criteria in which fulfill prerequisite of a good congestion control algorithm

Evaluation of trace elements contaminations in muscles of Rutilus kutum (Pisces: Cyprinidae) from the Southern shores of the Caspian Sea

Background: There is little information about the trace elements (TEs) concentrations in the muscle tissue of Caspian kutum (Rutilus kutum) in the South Caspian Sea. Methods: A total of 51 R. kutum specimens were caught at five fishing stations (Gorgan, Sari, Kiashahr, Anzali, and Astara) in the South Caspian Sea from September 2018 to January 2019. The inductively coupled plasma-optical emission spectrometry (ICP-OES) was employed to measure the TEs concentrations in the fish muscles. Results: The maximum concentrations of Al (7.2 ppm), Pb (0.07 ppm), and Ni (0.02) were reported in Astara, and the highest concentrations of As (0.2 ppm), Cu (0.49 ppm), Cr (0.12 ppm), and Zn (1.56 ppm) were reported in Sari and Gorgan. The TEs concentrations measured in the fish muscles (except Mg, Zn, As, Al, Na, and S) had no significant differences among the sampling areas. The TEs concentrations were higher in the eastern areas (Sari and Gorgan) than in the western areas (Astara, Anzali, and Kiashahr) excluding As and Al. The concentrations of Pb, Zn, Mn, Cu, Sn, Sb, Al, Cr, and Cd in muscles of R. kutum were found to be significantly lower (P < 0.05) than the maximum permitted levels according to the WHO/FAO standards, while As concentrations were comparable to these standards. Conclusion: The TEs concentrations in different fishing stations of Kiashahr, Anzali, and Astara, located in the southwestern areas were respectively compared with those obtained from Sari and Gorgan, located in the middle and southeastern shore of the Caspian Sea. According to the results, the TEs concentrations obtained from the fish muscles cannot pose a threat to human health. Keywords: Caspian Sea, Rutilus kutum, Elements, Human healt

Parasitic worms and their histopathological effects in four sturgeon species from the southwest shores of the Caspian Sea

This study conducted to provide the status of parasite communities of four sturgeon species viz. Acipenser stellatus, A. gueldenstaedtii, A. nudiventris, and Huso huso in the southwest of the Caspian Sea and their histopathological effects on the examined fishes. For this purpose a total of 93 individuals of four sturgeon species were caught in two fisheries regions from the southwest of the Caspian Sea (Guilan Province, Iran) from March 2010 to May 2011. The histological slides of the infested tissues of the examined fishes were prepared for study of the histopathological effects of the parasites. Classical epidemiological variables, including mean intensity, prevalence, abundance and dominance were calculated for overall samples, grouped by season, geographical region, and sex. Five worm species, including two nematodes (Cucullanus   sphaerocephalus and Eustrongylides excisus larvae), one cestode (Bothrimonus fallax), one acanthocephalans (Leptorhynchoide plagicephalus) and one digenean trematode (Skrjabinopsolus   semiarmatus) were found in examined sturgeons and their histopathological effects on the fish tissues were assessed. Based on the results, the diversity of the parasites (including freshwater ones) in the southern part of the Caspian Sea have decreased since the time of the first study in 1972. This may be related to unfavorable conditions in freshwater ecosystems

A survey on the consumption, knowledge and attitude of pregnant women toward the efects of folic acid on pregnancy outcome in Tabriz

ObjectiveWhile the effects of folic acid are well established in prevention of Neural Tube Defects (NTDs), these diseases have a high prevalence in Iran. In order to encourage folic acid supplement use in pregnancy, it is important to promote the awareness of women of childbearing age regarding folic acid importance in preventing NTDs. The aim of the present study was to study the knowledge and attitude of pregnant women on the effect of folic acid on pregnancy outcome and its use during pregnancy.Materials and MethodsA questionnaire was completed by 400 women from postnatal and prenatal wards/clinics using random sampling. The questionnaire included questions regarding demographic information, folic acid consumption in pregnancy and the attitude and knowledge of the participants on folic acid  supplementation and the source of information on folic acid supplementation.The questions were aimed at subjects' knowledge of folic acid effects on fetal growth and development and prevention of NTDs and not prevention of anemia. Data was analyzed by SPSS software (ver. 13.5).ResultsAbout 89.9% used folic acid supplements at some point of the pregnancy and 53.7% knew it was beneficial for the fetus. Approximately, 25% and 34.8% of those who used folic acid believed that it was most useful when taken preconception and during the first trimester, respectively. Only 15.4% knew itcould prevent NTDs. The most common information sources for folic acid use were physicians.ConclusionAwareness and use of folic acid were most prevalent among Iranian women, especially among educated ones. The results showed areas in which further work could be helpful to improve awareness regarding the benefits of folic acid.Key words: Folic acid;pregnancy; knowledge; neural tube defects (NTD

Should the oxygen source be considered in the initiation of KCl-induced high-temperature corrosion?

The role of two oxygen sources, oxygen and water vapor, in the initiation of KCl-induced high-temperature corrosion was addressed by studying two high-alloyed commercial materials at 550 \ub0C. The differentiation between the two oxygen sources was implemented with 18O-enriched water and 16O2. Based on the results, the solid-solid reaction between KCl(s) and the protective oxide on the alloy surface appeared to be more responsible for corrosion than the gas-solid reaction between KCl(g) and the protective oxide. Water was more involved in the abovementioned reactions than O2: 18O was the main oxygen isotope found in the formed surface oxides and intermediates

Enhancing Cellular Automata via Tabu Search for Optimal Operation of Hydropower Systems

One of the environmentally-friendly solutions to meeting energy consumption is multi-reservoir hydropower systems. The operation of a multi-reservoir hydropower system is an entirely complex problem due to a wide range of decision variables. Classic algorithms often get stuck in the local optimum and cannot successfully address these problems. Modern algorithms are more effective than classic ones, although their computational time is very high. In this study, an innovative hybrid model is proposed, called cellular automata-tabu search (CA-TS) to optimally operate multi-reservoir systems. For simplification, CA divides the problem into several sub-problems, which the number of them is the same as the length of operation period. Each sub-problem is solved by TS so that the net benefit of the power generation is maximized. For comparison purpose, a non-linear four-reservoir benchmark problem is considered to evaluate the proposed method. Finally, the results are compared with the existing results obtained by GA, PSO, and CA-NLP, showing the efficiency of CA-TS