فصلنامه علوم و فناوری دریا
سال بیست و پنجم شماره 100 (زمستان 1400)

The detection of the diver signature that diving with an open circuit system is important for several reasons, including identifying hostile divers in case of intrusion into underwater infrastructure, warning of divers entering into the aquaculture areas, preventing their collision with vessels, and instantaneous monitoring of their operations. In this paper, a deep convolutional neural network optimized by Bayesian method is used to detect divers. In order to adapt the problem to the intended deep network, after collecting the required data, bayesian optimizer search method is used to fine-tune important hyperparameters. After achieving the optimal values of important hyperparameters, three models of Bayesian, Alexnet and Darknet19 are used to classify signals in the form of two classes of Diver and No-Diver; as the results show, Bayesian search method, in addition to increasing the accuracy of training model, significantly saves calculation time in accordance to the benchmark models. So that in a total time of 1772 seconds the average square error of 0.00091977 is calculated.

The construction of a suitable breakwater is of great importance for the protection of the coast and offshore facilities. When the wave hits the breakwater, part of it is reflected and this part hits the wave that is attacking the structure, which causes water turbulence in front of the breakwater. If the turbulence is severe, it can cause the heel of the breaker to heal over time. Design engineers are forced to use high reliability coefficients in the design in order to solve the problems of stability and bed erosion in front of various breakwaters exposed to high waves. Today, engineers have come up with a suitable solution to solve this problem and reduce the cost of rubble mound breakwater, and that is to use breakwater with optimal porosity. It is now necessary for design engineers to calculate the wave reflectance of porous breakwaters. In this research, using a combination of two finite element numerical methods (FEM) and boundary element method (BEM) for breakwater and fluid modeling has been investigated, so that the finite wave geometry breaker, ‌ Finite components and fluid environments are modeled by the boundary element method. The results show that increasing the porosity increases the reflectance, which will decrease with increasing wavelength.

This paper investigates the output-only methods in recognizing system identification and modal parameters of infrastructures, such as bridges and offshore platforms, etc., as an alternative to traditional methods such as impact testing and visual inspection. In engineering sciences, system identification means identifying a structural system's dynamic characteristics, i.e., stiffness, mass, damping or, Modal shapes, natural frequencies, and damping ratios, called structural identification. In this article, after defining the concepts of system identification and output-only, time domain, frequency domain, and time-frequency domain methods are reviewed. In the end, the latest research on this subject is pointed out. Finally, a simply supported beam has been modeled in finite element software, and the frequencies and shapes of the modes are compared to those coded in MATLAB program. The output algorithms' results (SSI method) showed good agreement with the finite element model, which can be considered a reliable method for health monitoring and damage detecting structures.

The location of Chabahar coastal areas on the development circuit requires knowledge of the environmental characteristics of this area for comprehensive planning. The genealogy of flood risk is very important for executives in planning and preparing the coast. One of the main drivers of floods on rainforest shores is that by identifying its behavior, floods can be managed Precipitation is one of the most variability climatic elements that it has complex behavior, spatially in arid and semi- arid arias. Therefore investigation of precipitation characteristics in a region has significant effects on the environmental planning. The recognition of precipitation characteristics of a region, its monthly and seasonal distributions, intensity, duration and amounts can result to determine the different types of precipitations patterns in a region. In this paper by using the daily precipitation data of Chabehar synoptic station (during 1985-2013) 280 rainy days from total days (4817 days) was obtainedFinally by applying a cluster analysis on the 183 rainy clusters in a 183*4 matrix, five patterns of precipitation types was recognized and the characteristics of these types were analyzed.

Coastal zones are one of the invaluable areas on earth with considerable effects on development. The interaction of two ecosystems, land and water, has resulted in a high level biodiversity. Sustainable development, which considers both aspects of ecosystem and Socio-economic system, can be considered as an appropriate approach for coastal zone management. This would be the strategy for Integrated Coastal Zone Management (ICZM). Due to the requirement of wide actions in ICZM toward several objectives and goals at the same time, there is a necessity of establishing an appropriate Monitoring (M) and Evaluation (E) system. The aim of M & E system for ICZM includes monitoring ecological and socio-economic trends; assessing the achievement of goals and objectives; assessing the impacts of ICZM; ensuring existence of correction mechanisms and enhancement of goals and mitigation plans. Indicators are key issue in the monitoring and evaluation procedure. The aim is to apply the indicators to evaluate the outcomes of ICZM and direct them toward the sustainable development principles. Such indicators were classified in three categories, namely: socio-economic, environmental and institutional. Customization of indicators and making them standard on the basis of national strategies and also availabilities are vital in this regard. In the present study the organization of the structure of M&E for ICZM is introduced and application of indicators based on sustainable development paradigm in the DPSIR model is presented. The indicators are customized and standardized based on the national strategies and availabilities and a number of new indicators are introduced.

The performance of ports is a function of hardware and software. The purpose of this study was to investigate the impact of marine and port systems on the performance of the Ports Authority and the level of stakeholder satisfaction in the General Administration of Ports and Maritime Affairs of Bushehr. From the perspective of the research method, this research was descriptive-survey and from the perspective of purposefulness, it was applied. First, using the literature and research background, the effects of marine and port systems on ports and customer satisfaction were identified. Then, a 14 question questionnaire was developed in Bushehr Ports and Maritime Administration to examine these factors. Its validity was confirmed through content and form and its reliability was confirmed according to Cronbach's alpha value (0.957). Finally, the statistical analysis of the questionnaires was done through the partial least squares technique and PLS software. Research findings showed Marine systems have affected 3 dimensions of port operations and 2 dimensions of customer satisfaction and port systems have affected 6 dimensions of port operations and 3 dimensions of customer satisfaction.