جستجوی مقالات مرتبط با کلیدواژه "sensitivity" در نشریات گروه "مهندسی دریا"

Estuaries and bays are areas with a wide range of hydrodynamic and morphological phenomena. The existence of this diversity in environmental processes will lead to complex and sometimes unknown interactions in their structure. Understanding the behavior and environmental conditions of these beaches will improve the attitude of coastal users for better management of these areas. Many classifications have been made by researchers to understand the behavior of this coastal environment. The dimensionless VU parameter is a numerical parameter to facilitate speed, accuracy as well as cost reduction in the classification of this coastal environment. This parameter classifies the estuaries into three categories: tidal domination, wave domination, and mixed energy, based on the relative strength of the tides and the river flow relative to the wave infiltration. Each of these classes has its own behavioral characteristics. The purpose of this study is to identify the type of performance of the North Persian Gulf estuaries and sensitivity measurement The dimensionless VU parameter in the classification of morphodynamic class of Persian Gulf estuaries. Morphological classification was used as the basic criterion for validation and Hayes hydrodynamic classification was used as a comparison tool. For this purpose, data from observing the trend of changes from satellite images, wave data and tides and meteorology have been used. To classify the dimensionless parameters of the estuaries, the tidal amplitude, the area of the estuaries and the tidal prism in the estuaries have been calculated. The results of morphological classification indicate that the study area is dominated by tides and the results of Hayes hydrodynamic classification with 96% accuracy have presented similar results to morphological classification. In contrast, the dimensionless parameter VU with poor accuracy of 53% presented poor results in classification. By examining the calculation results, the error rate of the dimensionless parameter VU in small estuaries and tidal domains has been determined. By defining the ratio of wave height to tidal amplitude (H / TR), regression lines of difference intervals, the dimensionless parameter VU with morphological classification is determined. It was also found that in a constant ratio of wave height to tidal amplitude, with increasing wave height, the percentage of classification the dimensionless parameter VU error increases. And also at a constant wave height, with decreasing tidal amplitude, the percentage of the dimensionless parameter VU increases.

The occurrence of faults, and consequently the loss of Autonomous Underwater Vehicles (AUV) may create catastrophic outcomes to their owners. Identification of these faults and their classification provide useful information result in the detection of system bottlenecks in the design process. This paper examines the basic faults of AUVs, and studies the failure probability of their components and subsystems. The paper is then builds up the fault tree model of the AUV from its identified faults and structural Topology to highlight its critical paths, critical sub-systems, components importance, and cut-set importance values. The reliability of the AUV is then calculated from its fault tree model in the absence/presence of uncertainty associated with the failure probability of basic events. Fuzzy approach is used for handling the uncertainties. The sensitivity of the vehicle failure to the variation of the failure probability of system components is also calculated by using an innovative way. By the aid of the results of paper, the AUV reliability can be assessed at any arbitrary time frame, the appropriate preventive and predictive maintenance time be determined and by recognition of the AUV failure path, make the system more fault tolerant.