• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.375-378
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• 2009

대부분의 선박에서 송신하는 AIS 위치정보는 오차범위가 약 30미터인 일반적인 GPS 데이터에 의존하였다. 그러나 최근 DGPS의 보정정보를 활용하여 위치정확도를 개선할 수 있는 환경이 제공됨에 따라 고가의 DGPS 비콘리시버 없이 AIS 기반으로 DGNSS 메시지(17번)를 방송함으로써 위치정보를 보다 정밀하게 사용 할 수 있다.

• 동력기계공학회지
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• 제22권6호
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• pp.20-27
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• 2018

Vessel maneuvering problem in the harbor area is generating considerable interests in terms of marine cybernetics. In this sense, the vessel is operated and moves at ultimately low or zero speed in shallow water area. So the vessel is usually aided by the cooperation with thrusters, main propulsion system, tugboats and pilots, etc. In this paper, we suggest a new vessel berthing technique using dampers and winches as a solution for excessively complicate and dangerous berthing work. In the proposed berthing method, in order to manipulate the actuators (winches and dampers), a simple and heuristic control strategy is applied for a basic experiment. Finally, experiments are conducted to verify the effectiveness of the proposed automatic vessel berthing strategy based on the heuristic control method.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.80-83
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• 2021

The article analyzes and shows the rapid development information and telecommunication technologies, and their capabilities are becoming unprecedented for human development, effective solutions to many professional problems. The analysis of information and communication technologies of education used in higher educational institutions of Ukraine confirmed that for the effective use of special teaching methods, as well as software and technical teaching aids, it is necessary to have a trained teaching staff and students.

• 한국기계가공학회지
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• 제21권7호
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• pp.43-52
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• 2022

Design of a controller for a high-precision servo control system has been a popular topic while finding optimal parameters for multiple controllers is still a challenging subject. In this paper, we propose a practical scheme to optimize multi-parameters for the robust servo controller design by introducing a new cost function and optimization scheme. The proposed design method provides a simple and practical tool for the systematic servo design to reduce the control error with guaranteeing robust stability of the overall system. The reduction of the position error by 24% along with a faster convergence rate is demonstrated using a typical hard disk drive servo controller with 41 parameters.

• 한국기계가공학회지
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• 제21권8호
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• pp.32-42
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• 2022

Asymptotic tracking of a non-minimum phase nonlinear system has been a popular topic in control theory and application. In this paper, we propose a new control scheme to achieve asymptotic output tracking in anon-minimum phase nonlinear system for periodic trajectories through an iterative learning control with the stable inversion. The proposed design method is robust to parameter uncertainties and periodic external disturbances since it is based on iterative learning. The performance of the proposed algorithm was demonstrated through the simulation results using a typical non-minimum nonlinear system of an inverted pendulum on a cart.

• Journal of Contemporary Eastern Asia
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• 제12권2호
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• pp.35-47
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• 2013

This study aims to understand haiku phenomena from the viewpoint of communication, which emerges from reciprocal relationships among haiku poets, haiku societies, media on haiku, and other establishments relating to haiku. Such an analytic point of view, which tries to consider both the operation of each autonomous agent and that of the whole system consisted by the agents, is included in the realm of second-order cybernetics. The operation of a system cannot be reduced completely to a system's individual components, which is why such a viewpoint is required. Fundamental informatics, which is employed as a theoretical framework, and two haiku movements, which include shin keiko haiku ("new-trend" haiku) and dento ha haiku (Hototogisu-school haiku), forming an important part of modern haiku history, are the focus of this study. As a result, modern haiku history is considered to be an evolution of a haiku system, whose main incentive is an awareness of the production mechanism of haiku communication occurring through second-order observations in the system. This study also illuminates how haiku poets, haiku societies, and media covereage of haiku play roles in the evolution of the haiku system.

• 성인간호학회지
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• 제17권4호
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• pp.635-645
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• 2005

Purpose: This study was attempted and completed in order to settle down and qualitatively improve web-based nursing education by evaluating effect and managing strategy of tutor. Method: The development of tutor's managing strategy was based on "The Self-regulated Learning" and "The supportive Learning", then it was applied to 79 learners in one of the cyber-learning centers. After applying the tutor's managing strategy, self-regulated learning scale, attitude for school, preference for computer and academic achievement were evaluated. The development of tutor's managing strategy for web-based nursing education are consisted of participation promotion, psychological support and motivation, recognition and promotion strategy of learning activity, management strategy of evaluating stage. Result: The levels of learner's self-regulated learning, recognition, behavior, attitude on the school and learning achievement were meaningfully increased in statistics after applying for the managing strategy of tutor. The motivation level and learning participation kept high scores from the beginning with no significant statistical changes. Conclusion: It is required to develop an educational program for cultivating well-educated tutors in order to help the effective learning process of nurses based on understanding characteristics of learners.

• Wind and Structures
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• 제29권6호
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• pp.405-416
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• 2019

Aerodynamic characteristic of a small scale wind turbine under the influence of an incoming uniform wind field is studied using k-ω Shear Stress Transport turbulence model. Firstly, the lift and drag characteristics of the blade section consisting of S826 airfoil is studied using 2D simulations at a Reynolds number of 1×10⁵. After that, the full turbine including the rotational effects of the blade is simulated using Multiple Reference Frames (MRF) and Sliding Mesh Interface (SMI) numerical techniques. The differences between the two techniques are quantified. It is then followed by a detailed comparison of the turbine's power/thrust output and the associated wake development at three tip speeds ratios (λ = 3, 6, 10). The phenomenon of blockage effect and spatial features of the flow are explained and linked to the turbines power output. Validation of wake profiles patterns at multiple locations downstream is also performed at each λ. The present work aims to evaluate the potential of the numerical methods in reproducing wind tunnel experimental results such that the method can be applied to full-scale turbines operating under realistic conditions in which observation data is scarce or lacking.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 춘계학술발표회
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• pp.209-213
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• 2005

현재 우리나라는 선박자동식별장치(AIS)를 육상기지국 22개소, 운영시스템 11기 및 전국 통합망 구축사업을 완료하여 AIS 망과 시스템이 본격적으로 운용되고 있다. 그러나 항만 또는 항만 인근에서 레이더 탐지구역의 제한으로 인하여 한정된 서비스 범위를 갖는 해상교통관리제도(VTS)와 AIS를 연계하여, 서비스 범위를 인접해역과 연안수역까지 확대하여 선박교통을 관리할 필요성이 제기되고 있다. 따라서 본 논문에서는 기 구축된 AIS 시스템의 현황을 분석하고, 현행 시스템의 기술적 개선사항과 운영적 개선사항을 제시한다.

• 드라이브 ㆍ 컨트롤
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• 제11권3호
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• pp.7-13
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• 2014

Everyday about 90% of cargos are delivered by ships, and thousands of vessels enter and depart the international container harbors such as Shanghai, Singapore, Hong Kong, Busan, Rotterdam, etc. Maneuvering at harbor is known as the most sophisticated and difficult procedure, because the effectiveness of actuators during low speed berthing is reduced. In this paper, a new berthing method is discussed. Tugboats are combined with damper systems to ensure safe berthing. A mathematical model describing the interaction between unactuated ship, tugboats and damper systems is presented. An optimal controller is designed to maneuver the ship without oscillation and overshoot. MCL (Marine Cybernetics Lab) model ship is used to evaluate the efficiency of the proposed approach through MatLab simulation.