• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.15-21
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• 2017

In this paper, the decentralized fuzzy observer design technique is presented for discrete-time nonlinear interconnected systems, which are assumed to be with unknown interconnections. To design the decentralized fuzzy observer, the design problem is considered and the performance function is defined to solve the design problem. Based on the performance function, the sufficient condition is derived for the observer design, and its condition is formulated into linear matrix inequalities. Finally, by the simulation result, the validity of the proposed observer design technique is shown.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.1-9
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• 2008

Five bases for of highways are sight distance, vehicle stability, driver comfort, drainage and aesthetics. Among these bases, the sight distance is the most critical one in the highway alignment design. It is certain that highways and drivers' observation actions are 3-dimensional in nature. But, the highway alignment design and the sight distance analysis have been performed on 2-dimensional planes because of various constraints and complexity of calculating 3-dimensional sight distance. The purpose of this study is to derive a model for determining exact available sight distance in 3-D combined horizontal and vertical alignments. Application of the model is illustrated using numerical examples. The proposed model should be useful in quantifying the criteria for 3-D highway alignments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.792-800
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• 2021

This paper presents a new structure for a linear active magnetic bearing using a Halbach magnet array. The proposed magnetic bearing consisted of a Halbach magnet array, center magnet, and single coil. The proposed linear active magnetic bearing has a high dynamic force compared to the previous study. The high dynamic force could be obtained by varying the thickness of a horizontally magnetized magnet. The new structure of Halbach linear active magnetic bearing has a high dynamic force. Therefore, the proposed linear active magnetic bearing increased the bandwidth of the system. Magnetic modeling and optimal design of the new structure of the Halbach linear active magnetic bearing were performed. The optimal design was executed on the geometric parameters of the proposed linear active magnetic bearing using Sequential Quadratic Programming. The proposed linear active magnetic bearing had a static force of 45.06 N and a Lorentz force constant of 19.54 N/A, which is higher than previous research.

• Computational Structural Engineering
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• v.10 no.3
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• pp.30-38
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• 1997

본 논문에서는 선형파괴역학의 관점에서의 파괴강도해석 기법들에 대해서 포괄적으로 논의하였다. 파괴강도해석을 위하여 규정되어야 할 파라메타들의 결정방법들에 대하여 설명하고 이들 파라메타들을 파괴강도설계에 적용시키는 과정들을 압력용기를 예를 들어 체계적으로 설명하였다. 선형파괴강도해석을 근간으로 한 파괴강도설계 방법으로 구조물을 설계하면 파괴응력에 대한 안전계수를 정확하게 산정할 수 있어서 안전성이 제고된 구조물을 설계.제작할 수 있게 될 것이다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.137-141
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• 2000

본 논문에서는 전력증폭기의 선형성을 광대역으로 개선하기 위하여 Delay 라인의 영향에 대하여 고려하려다. 사용된 전력 증폭기의 이득은 37dB이고, 3단의 l1W급으로 설계되었다. Error 증폭기는 4단으로 설계되었으며 이득은 55dB이다. 그리고 크기와 위상을조절하기 위한 장치로 Vector modulator를 사용하였으며, 또한 방향성 결합기 및 전력분배기를 설계하였다. 각 모듈을 통합하여 주파수 2.11GHz에서 2.2GHz까지 Delay 특성을 고려한 광대역 선형 전력 증폭기를 설계하였으며 대역폭이 30MHz에 걸쳐 IMD성분의 제거 특성이 25dB이상의 개선 효과를 얻었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.558-570
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• 2015

A study on the green ship design for Ultra Large Container Ship (ULCS, 18,000 TEU Class Container Ship) was performed based on the four step procedures of the initial design and hull form optimization to maximize economic and propulsive performance. The first, the design procedure for ULCS was surveyed with economic evaluation considering environmental rules and regulations. The second, the characteristics of single and twin skeg container ships were investigated in view of initial design and performances. The third, the hull form optimization for single and twin skeg ships with the same dimensions was conducted to improve the resistance and propulsive performances at design draught and speed by several variations and the results of the optimization were verified by numerical calculations of CFD and model test. The last, for the estimated operating profile of draught and speed, the hull forms of single and twin sked ships were optimized by CFD. From this study, the methodologies to optimize the hull form of ULCS were proposed with considerations during the green ship design and the improvement of the energy efficiency for the optimized hull forms was confirmed by the proposed formula of the total energy considering design conditions, operating profile and fuel oil consumption.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.72-83
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• 1997

The purpose of present study is to find an appropriate hull shape of a container ship which can operate along the coast and through canals. A 200TEU class container ship is designed with dimensional modifications of an existing 140TEU container ship which is a domestic coastwise vessel. For the fore-body shape including bulbous bow. additional modification is done by changing the sectional area curve and frameline shape using the data of series resistance test. The model tests are performed in the towing tank to measure total resistance sinkage and trim of the model. And a finite-difference method based on MAC method is utilized to analyze the flow field around the ships in deep and restricted water. From the result of model test and numerical analysis, the resistance characteristics of the designed hull form are predicted.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.118-126
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• 2024

In this paper, the research contents and results related to the automation of the hull-form optimal design of container ships are summarized. A container ship is a ship that generally operates near Froude number of 0.26. To implement hull-form optimal design automation for ships operating at this speed, an optimization algorithm, a hull-form change algorithm, a ship performance prediction algorithm, an automation algorithm, and an iterative calculation technique were applied to develop a numerical analysis computer program that enables hull-form optimal design automation of the container ship, and it was named HOTCONTAINER. In this study, a sensitivity analysis algorithm was developed and applied to appropriately set design variables for hull-form optimal design. To understand the reliability and real ship applicability of the developed algorithm, a numerical analysis was performed on KCS(KRISO Container Ship), a container ship that has been studied in various ways worldwide. Consequently, the optimal ship was derived, and the wave resistance, wave pattern, and wave height of the target and optimal ship were compared. In conclusion, compared the target ship, the optimal ship a 47.63% decrease in wave resistance, and the displacement and wet surface area decreased by 0.50% and 0.39%, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.677-685
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• 2014

Despite the significant benefits of BIM (Building Information Modeling), it is not being vitalized for the facilities that are designed based on the horizontal and vertical alignments because of the lack of flexibility in manipulating surface models generated based on alignments. Alignment-based design produces a surface model in one piece through the definition of the typical cross-section along the alignment. Therefore, linking these alignment-based 3D surface models, that are not modularized and difficult to partition, to the required attribute information is very difficult This paper presents design of a flexible BIM technology suitable for the alignment-based civil infrastructure by providing the partitioning functionality for surface models, the contents library for cross-sectional design components, and the attribute information along with the critical functionalities needed for the design, construction and maintenance of alignment-based civil infrastructure.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.42-53
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• 2002

This paper is for the hull form development of high-speed passenger ship in the Yellow Sea. To carry out hull form development in Yellow Sea, a catamaran which is designed for high-speed as well as comfortable passenger vessel up to now is selected and investigated. For this, environments of the Yellow Sea such as tide, water depth and so on are considered as important factor. The economical efficiency of the designed ship is considered too. In order to estimate the resistance characteristics of the designed hull form, numerical simulations and model test are performed.