選擇卷期
- 期刊
In this paper, the antimicrobial effect of inert flue gas on indicator microorganisms in ballast water was investigated based on a 265h test. The inert flue gas consists of nitrogen (N_2) and carbon dioxide (CO_2) the microorganisms include Chlorella and Escherichia coli. Within the scope of the test, the killing effect of the microbes treated by combining N_2 and CO_2 was higher than that of using only either N_2 or CO_2. When the dissolved oxygen concentration in the ballast water was 0.5 mg/L and the pH value was 6, the killing effect was the highest. At this time, the mortality rate of Chlorella sp. and E. coli reached 99.99%, and 99.98%, respectively. After the experiment, property of the ballast water treated by N_2 and CO_2 were analyzed. The dissolved organic carbon concentration was lower than the recommended minimum concentration of 5 mg/L. The concentration of particulate organic carbon was higher than the standard value of 0.3%.The experiment proposes a new method for ballast water treatment of large ocean-going vessels in the future.
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Driven by the development of world's technology, the concept of Internet of things (IoT) not only promotes the leapfrog development of global information technology, but also makes computer and communication technology realize further perfection. IoT technology enables the global sharing of network resources and the overall perception of information to achieve the goal of ＂interconnection of all things together,＂ which is the third wave of world's information industry development after the computer and Internet. Recently, the rapid expansion of IoT technology has made many conventional industries more intelligent. With the accelerated expansion of port traffic, many conventional ports are facing the transformation of operation mode. They urgently need to improve the service quality of infrastructure, comprehensive processing capacity for information and the optimized allocation of resources of their related logistics parks. Therefore, from the aspects of intelligent supervision, intelligent service and technology security, this study constructs the data envelopment analysis (DEA) framework of factors influencing the intelligent transformation of international commercial ports with the application of IoT technology. This study hopes to help port managers to improve the operational performance through an intelligent cloud connection, and to transform conventional port to intelligent commercial port 4.0 as soon as possible.
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This study aims to improve maritime safety by enhancing administrative management based on human factors. This study used Fuzzy analytic hierarchy process to analyze the risks and threats regarding safety maritime criteria. Establishing administrative reform is given the highest priority. First, the current model for crew training system is explored. Second, the marine surveyor is examined to determine if it is professional enough for inspection work. Third, the investigation system used by maritime safety investigators should be inspected. The suggestions mentioned expect to establish a maritime administrative reform that could pave the way for the application of maritime safety around the world.
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Ice navigation is currently one of the important issues in path planning studies. Most studies are using sea ice models or ice charts for large-scale path planning, but the weather and ice conditions in the polar waters usually change quickly and are not easy to predict. Under these conditions, small-scale path planning that can be adjusted in time for sea ice collision avoidance is needed. This study uses marine radar imaging to reconstruct the ice navigation scene, and establishes a visualization function of sea ice warning on the radar image. We combine the bidirectional rapidly-exploring random tree (B-RRT) algorithm and the greedy algorithm to propose a path planning algorithm that generates various path planning schemes for ice navigation. After a number of path planning schemes are quickly generated, the path risk index proposed in this study can be used to evaluate and choose a relatively optimal path planning scheme with lower risk, as well as serve as an assistant reference for path planning decisions in ice navigation.
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Many techniques have been developed to produce landslide susceptibility maps. However, mapping the spatial distribution of landslide susceptibility involves critical steps. This study evaluated susceptibility to the occurrence of shallow landslides in upstream areas of the Jingshan River, Taiwan, where heavy rainfall has resulted in increased landslide occurrence and reservoir sedimentation. The landslide susceptibility case study was conducted using logistic regression, an instability index method, and support vector machine (SVM). A selection procedure was first developed to identify the factors influencing landslide occurrence. Historical landslide data were used to assess the corresponding parameters of each model. The receiver operating characteristic curve was then used to evaluate the accuracy of model results. The results indicated that the instability index method underestimated landslide susceptibilities in areas near the river. The instability index method was highly affected by the classifications of model factors. Of the models, the SVR model was the most accurate regarding landslide susceptibility in the study area. Employing this framework, governments may implement suitable, cost-effective improvements to structural measures and land-use planning.
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This document deals with the problem of passive fuzzy controller design with the state-derivative feedback approach for the nonlinear stochastic singular systems. Recently, the singular systems have a greater focus on literature because they can keep more physical system characteristics than conventional systems. At first, the Takagi-Sugeno fuzzy stochastic singular models are used to represent the nonlinear stochastic singular systems. Then, the state-derivative feedback approach and parallel distributed compensation method are employed to design the passive fuzzy controllers. In the design process, the Lyapunov stability conditions are developed subject to multiple performance constraints, including the passivity constraint and decay rate constraint. According to these Lyapunov stability conditions, the proposed fuzzy control problem can be effectively shifted into the linear matrix inequality problem that can be solved by using the convex optimal programming algorithm. At last, two examples are provided to verify the applicability and effectivity of the proposed passive fuzzy controller design approach.
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In this research, Kuroshio-induced vortex shedding in the lee of Green Island was numerically studied using the three-dimensional Princeton Ocean Model. The temporal and spatial characteristics of the vortex street were analyzed at different tidal levels, wind fields and water depths. The numerical results were validated by comparing with in-situ measurements from the Green Island tidal station, shipboard acoustic doppler current profiler (ADCP), conductivity-temperature-depth (CTD) profiler, and moderate resolution imaging spectroradiometer (MODIS) satellite image datasets. Also, the three-dimensional results of velocity, temperature, and salinity fields were compared well with observational data. Furthermore, the influence depths of the wind effect and vortex shedding were found to be approximately 100 and 300 m, respectively. The aspect ratio and dimensionless width were evaluated to be 3.64 and 1.46, respectively. In addition, the temporal scales (Strouhal numbers), and propagation speeds were analyzed at various water depths. Finally, the elongation of the Kuroshio-induced vortex street was studied under wind and tide effects at various water depths.
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Sightseeing and tourism not only brings economic benefits to the local community but also drive the development of related industries. In 1992, when the Matsu's battlefield mission was dissolved, tourism became one of the key development strategies to boom the region. Although the number of visitors to Matsu Islands has risen significantly in recent years, how to increase the island's willingness to revisit the island has been an important issue. Since local tourism has its own characteristics, island tourism marketing strategies should be different. Many previous studies have quantified the relationship between tourism area satisfaction and willingness to revisit, but there is no research analyzing of island tourism marketing importance performance to evaluate the influencing factors of revisiting willingness. Based on the local tourism marketing position, this paper mainly adopts the SAVE marketing model, taking the Matsu Islands as an example, to explore the key influencing factors on island tourism revisit intentions. Next, it transforms the model into the island tourism marketing mix, and conducts an empirical analysis of the key influencing factors on Matsu tourism revisit intentions by the Importance-Performance (IPA) method. The study indicates that the main criteria of the desire to revisit Matsu Islands are ＂Integration Solution＂ and ＂Tourism Education,＂ while the key influencing factor of the major improvement area is ＂The Integrity of Transportation Construction.＂ It is suggested the local government and related companies strengthen marketing and improve the current situation. The findings may serve as a reference for the allocation of tourism resources in Matsu Islands.
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Underwater vehicles are equipped with a device for discharging projectiles, called the underwater discharge system. Because these vehicles have limited space, many studies have attempted to reduce the volume of the underwater discharge system while improving its performance. However, owing to the characteristics of the system, the occupied volume and performance conflict with each other. Therefore, minimizing the occupied volume while satisfying the required performance criteria is the most significant requirement in the design stage. To address this, an optimization problem for the underwater discharge system was mathematically formulated and solved using multi-objective genetic algorithms. Additionally, we proposed a method of using the surrogate modeling technique to find an optimum solution quickly. Linear regression, radial basis functions, and artificial neural networks were compared to generate an appropriate surrogate model. To evaluate the applicability of the proposed method, it was applied to optimize the design of an underwater discharge system. The results demonstrate that the proposed method can be effectively utilized to obtain the optimum design of an underwater discharge system within an acceptable time.
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The harbor tugboat operation is a very important business and process of Kaohsiung port. To ensure the safety of harbor tugboat operations and to reduce the occurrence of accidents, it is an important issue to conduct a risk assessment of tugboat operations for Kaohsiung port. Hence, the main purpose of this paper is employ the analytic hierarchy process (AHP) method to evaluate key risk factors influencing the harbor tugboat operations for Kaohsiung port. At first, a total of three evaluation dimensions with 14 preliminary risk factors are generated from literature and interviews of tugboat captains. We then applied the steps of AHP method and AHP experts' questionnaires to evaluate the key risk factors. The empirical results showed that: (1) 'Tugboat operators' is the most important risk evaluation dimension influencing harbor tugboat operations for Kaohsiung port in Taiwan. (2) In order of relative importance, The top six key risk factors influencing the harbor tugboat operations for Kaohsiung port are ＂judgment error,＂ ＂work fatigue,＂ ＂poor skills,＂ ＂communication misunderstanding,＂ ＂negligence of the relative motion between tugboats and commercial ships,＂ and ＂personality factors,＂ respectively. Furthermore, some recommendations concerning effective risk management strategies and advices are provided for harbor tugboat practitioners.