• 한국지능시스템학회논문지
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• 제22권3호
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• pp.312-318
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• 2012

최근에는, 극한 분야에서 해양로봇의 필요성이 제기되고 있으나, 그 기반이 매우 부족한 실정이다. 다행히 로봇경진대회가 활성화되고 로봇교육에 대한 수요가 증가하는 추세이므로, 해양로봇키트의 개발/보급을 통하여 해양로봇 연구개발/산업화 기반을 마련하고 전문인력을 양성하는 것이 바람직하다. 그런데, 기존에는 수중이동 및 표적 탐지/회피가 가능한 해양로봇경진대회용 수중형 자율운항 해양로봇키트가 없었다. 이 문제를 해결하기 위해서 수중이동성, 수중방수성 및 무게조절성이 우수한 보급형 해양로봇키트가 개발되었다. 개발된 키트의 성능 검증을 위해서 Surge, Pitch, Yaw, 장애물회피 등의 시험 평가가 수행되었다. 시험평가 결과는 개발된 키트의 실제 적용 가능성을 보여준다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권7호
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• pp.872-880
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• 2007

The development of a Marine Engine Room Simulator system for training and research is described. Development objectives of the system are for both student training, research and development work. The system includes a distributed server/client architecture for 1 to 1, or 1 to many client simulation operation through OPC server, complete separation of visual elements from the controlling routines and the ability to work on the mathematical model independent of the controller and visual systems. A graphical user interface for the man-machine interface has been developed and the mathematical model has been updated. Various engine room operational situations can be simulated. The use of marine engine room simulator for training of sea going engineers and its competency for STCW-95 is discussed.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2000년도 춘계학술대회
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• pp.139-139
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• 2000

• Journal of Advanced Marine Engineering and Technology
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• 제38권2호
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• pp.225-232
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• 2014

The traditional RAP (Redundancy Allocation Problem) of complex systems has considered only the redundancy of subsystem with homogeneous components. In this paper we extend it as a RAP of complex systems with heterogeneous components which is more flexible than the case of homogeneous components. We model this problem as a nonlinear integer programming problem, find its optimal solution by tabu search, and suggest an example of the efficient reliability design with heterogeneous components. In order to improve the quality of the solution of the tabu search, we suggest a modified tabu search to employ an adaptive procedure (1-opt or 2-opt exchange) to generate the efficient neighborhood solutions. Computational results show that our modified procedure obtains better solutions as the size of problem increases from 30 to 50, even though it requires rather more computing time. With some adjustment of the parameters of the proposed method, it can be applied to the optimal reliability designs of complex systems of ships.

• Journal of Advanced Marine Engineering and Technology
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• 제19권2호
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• pp.67-80
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• 1995

In order to control systems which are dominantly subjected to modeling errors and uncertainties, control strategies must deal with the effect of modeling errors and uncertainties. Since most of control methods based on system mathematical model, such as LQG/LTR method, have been developed mainly focused on stability robustness, they can not smartly improve the transient response disturbed by modeling errors and/or uncertainties. In this research, a fuzzy PID control method is suggested, which can stably improve the transient responses of systems disturbed by modeling errors as well as systems not entirely using mathematical models. So as to assure the effectiveness of suggested control method, computer simulations are accomplished for some example systems, through the comparison of transient responses.

• 수산해양교육연구
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• 제6권2호
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• pp.161-182
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• 1994

The steady rise in life expectancy resulting from progress in medical science and economic growth and improved living conditions is responsible for large and increasing-number of older peoples in our country. The older peoples who are increasing make up a large percentage of our total population. Now a day the percentage of older people 60 and 65 years old over compose around 8.7% and 5% of the total population in each. In spite of such a rapidly increasing trend of older population, there has had no provisions for elderly welfare in our country. The reason why some children do not want to take care of their older parents, and the other is the lack of elderly welfare, are responsible for large and increasing anxiety of livelihood and alienation to the number of older peoples. As mentioned above, especially studying Swedish elderly welfare model of many developed countries, it intend to provide many of the useful materials to make the elderly welfare systems in our country. The main research for Swedish elderly welfare are as follows : (1) Old age pension systems (2) Social service systems (3) Health care service systems (4) Housing care service systems.

• Journal of Advanced Marine Engineering and Technology
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• 제39권10호
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• pp.1031-1036
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• 2015

Proportional-integral-derivative (PID) controllers are widely used in industrial sites. Most tuning methods for PID controllers use an empirical and experimental approach; thus, the experience and intuition of a designer greatly affect the tuning of the controller. The representative methods include the closed-loop tuning method of Ziegler-Nichols (Z-N), the C-C tuning method, and the Internal Model Control tuning method. There has been considerable research on the tuning of PID controllers for single-input single-output systems but very little for multi-input multi-output systems. It is more difficult to design PID controllers for multi-input multi-output systems than for single-input single-output systems because there are interactive control loops that affect each other. This paper presents a tuning method for the PID controller for a two-input two-output system. The proposed method uses a real-coded genetic algorithm (RCGA) as an optimization tool, which optimizes the PID controller parameters for minimizing the given objective function. Three types of objective functions are selected for the RCGA, and each PID controller parameter is determined accordingly. The performance of the proposed method is compared with that of the Z-N method, and the validity of the proposed method is examined.

• Advances in Energy Research
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• 제6권2호
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• pp.103-129
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• 2019

While global demand for energy increases annually, at the same time the demand for carbon-free, sulphur-free and NO_x-free energy sources grows considerably. This state poses a challenge in the research for newer sources like biomass and shale gas as well as renewable energy resources such as solar, wind, geothermal and hydraulic energy. Although wave energy also is a form of renewable energy it has not fully been exploited technically and economically so far. This study tries to explain those reasons in which it is beyond doubt that the demand for wave energy will soon increase as fossil energy resources are depleted and environmental concerns gain more importance. The electrical energy supplied to the grid shall be produced from wave energy whose conversion devices can basically work according to three different systems. i. Systems that exploit the motions or shape deformations of their mechanisms involved, being driven by the energy of passing waves. ii. Systems that exploit the weight of the seawater stored in a reservoir or the changes of water pressure by the oscillations of wave height, iii. Systems that convert the wave motions into air flow. One of the aims of this study is to present the classification deficits of the wave energy converters (WECs) of the "wave developers" prepared by the European Marine Energy Center, which were to be reclassified. Furthermore, a new classification of all WECs listed by the European Marine Energy Center was arranged independently. The other aim of the study is to assess the technological state of the art of these WECs designed and/or produced, to obtain an overview on them.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2736-2750
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• 2022

As demands for the maritime communications increase, a variety of functions and information are required to exchange via elements of maritime systems, which leads communication traffic increases in maritime frequency bands, especially in VHF (Very High Frequency) band. Thus, effective resource management is crucial to the future maritime communication systems not only to the typical terrestrial communication systems. VHF data exchange system (VDES) enables to utilize more flexible configuration according to the communication condition. This paper focuses on the VDES communication system among VDES terminals such as shore stations, ship stations and aids to navigation (AtoN) to address efficient resource allocation. We propose a resource management method considering a MIMO (Multiple Input Multiple Output) technique in VDES, which has been widely used for modern terrestrial wireless networks but not for marine environments by scheduling the essential communication resources. We introduce the general channel model in marine environment and give two metrics, spectral and the energy efficiencies to examine our resource scheduling algorithm. Based on the simulation results and analysis, the proposed method provides a possibility to enhance spectral and energy efficiencies. Additionally, we present a trade-off relationship between spectral and energy efficiencies. Furthermore, we examine the resource efficiencies related to the imperfect channel estimation.

• Journal of Ecology and Environment
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• 제33권2호
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• pp.95-103
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• 2010

The archipelago in the southwest sea, Korea, was registered as Shinan Dadohae Biosphere Reserve by United Nations Educational, Scientific and Cultural Organization Man and the Biosphere (UNESCO MAB) on May 26, 2009. This study was conducted to determine a method of reconciling natural and anthropogenic processes and to enable sustainable development in the vicinity of the Shinan Dadohae Biosphere Reserve (SDBR). To accomplish this, the characteristics of SDBR with respect to biodiversity and cultural diversity were evaluated. In addition, a management plan regarding the wise use of the SDBR was developed while focusing on four parts: cultural support to induce motivation for native conservation and development; development and specification of fisheries and cultivation based on local community systems; restructuring of marine food products and resource transporting systems; activation and discovery of indigenous knowledge to enable networking between local residents, academia and the UNESCO-international society.