فصلنامه علوم و فناوری دریا
سال بیست و چهارم شماره 95 (پاییز 1399)

Underwater wireless sensor networks are a type of sensor networks that are submerged and communicate with each other by sound waves. The fundamental differences between underwater sound propagation and radio waves at ground level, on the one hand, and energy resource constraints, on the other hand, require new criteria for the design of underwater routing protocols. Most routing protocols are based on the location of the sensor nodes. On the other hand, maintaining the position of nodes in underwater sensor networks is the most important issue. In this paper, we propose a position-independent and cluster-based routing protocol in underwater wireless sensor networks called EECRU. The EECRU algorithm uses the concept of special nodes that act as headers. If no header is found, then this algorithm transfers data using the neighbor node method. It also uses the concept of CDMA to obtain information from different nodes and special nodes. The simulation results using MATLAB software confirm that the proposed algorithm is effective in increasing network lifetime and reducing power consumption.

AbstractWith the advent of quantum technology and its development and accelerating progress, in the near future, we will witness a new technological revolution and major changes in the various fields of science and technology that will transform the industrial, economic, political, military and cultural equations and relationships. In the meantime, the topic of electronic warfare due to being technology-driven will be greatly affected by these advances. And the essence of future electronic wars will change.Therefore, it is necessary to identify and analyze the opportunities and challenges with foresight and scenario writing and propose ways to counter them. Accordingly, in this study, using credible articles and sources, first, information on various types of stealth techniques and ways to counter them, then the capabilities of leading countries in the field of stealth aircraft as an offensive force and other forces as a defense force was presented and the future of this technology has been studied to the year 1410 SH. After analyzing the data and interviewing with the experts of this field, key factors and driving forces were identified. using scenario writing techniques with the help of scenario wizard software, three more likely scenarios in the form of pessimistic, moderate and optimistic were named smoked scenario, the transition stage scenario, and the quantum age scenario, respectively which were presented at the end of the paper.

Due to the uncertainty in modeling the forces acting on the submarine and determining the actual values of the model parameters, the actual behavior of the vessel always deviates from the simulated behavior. To solve this problem, it is necessary to design a measurement system that is able to determine the acceleration, rotational angles, rotational speeds and floating displacement during its movement. The purpose of this paper is to design and build a system for measuring and recording the required information, in order to analyze the dynamic and kinematic behavior of a vessel during underwater navigation and data optimization using motion constraints to intelligent INS. Acceleration, rotational speed and displacement in the direction of the three axes perpendicular to each other are measured over a maximum of 10 seconds.

Present study has examined an optimal strategy for potential investments that may be accepted to attract more ships. A mathematical model has been set up to identify the basic criteria used by shipping companies to evaluate a particular port. Then, a game theory approach has been used for a competitive model between several important ports to attract shipping companies through maximizing their utility functions. In this way, a secret game type with one turn has been suggested. The results showed that optimal investment strategy used by a particular port depends on1) current status of port relative to other competitive ports, 2) available resources in terms of manpower and capital, 3) profit forecasting and 4) other officials' responses relative to the capital. Present study informs a strong port to maximize returns in the case of winning in auction through choosing to invest in the port and minimizing potential losses as well as minimizing potential losses in the case of failure on auction through discarding any investment.

Today, the maritime industry is considered as a strategic industry and plays an indispensable role as one of the essential and fundamental pillars of economic growth and development on the path to the emergence and completion of each country. In our country, having more than 2,800 kilometers of border and access to free waters, as well as being on the path to the world trade corridor, can take advantage of the industry and design its economy based on a maritime economy. Identifying the effective factors in the growth and development of the transportation industry (including maritime transport) as a prerequisite and developmental infrastructure plays an essential and efficient role. Therefore, the purpose of this research is to identify the factors affecting the development of the maritime transport industry, which is an applied and descriptive-survey method. The statistical population of this study was Bandar Abbas Port Bureau staff members. 150 cluster samples were selected as sample. The data collection tool was a questionnaire whose reliability and validity were confirmed by the Cronbach's alpha (0.886) and by the professors and experts familiar with the subject. Data analysis was done by SPSS software and single-variable T test. The findings of the research showed that all identified factors affect the development of the maritime transport industry, and by investing in these variables, one can expect development and progress in this industry.

The use of silver nanoparticles for biomedical activities, air and water purification, food production, cosmetics, clothing and household products is very common. Due to their high stability, these compounds have a high potential for entering aquatic ecosystems and accumulating in sediments, water, and animal and plant tissues. The end result of the entry of these resistant pollutants into water resources is environmental degradation and aquatic pollution and a threat to human health. The main environmental problem of these pollutants is their adverse effects on non-target organisms, especially fish, which are directly consumed by humans and transmit toxins to humans. In the present study, the lethal effects of silver nanoparticles on guppies, which is an ornamental fish of the family Poecilia reticulate, were investigated. For this purpose, the acute toxicity of silver nanoparticles was studied on P. reticulate guppies with an average weight of 0.335±0.015 g to determine the lethal concentration of LC50 (h-96) percent of the fish population. In this experiment, fish in 6 treatments (with two repetitions for each treatment) were exposed to different concentrations of nanosilver including control, 0.25, 0.5, 0.75 1 and 1.25 ppm for 96 hours and Their mortality rates were recorded regularly. Toxicity test was determined using statistical analysis of probit in SPSS statistical software (version 22). Observations and statistical analysis showed that the LC50 (96-h) hour of nanosilver for guppies is 0.528 ppm.