• Journal of Korea Ship Safrty Technology Authority
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• no.7 s.25
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• pp.47-63
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• 2008

저항성능 측면에서 한국 어선선형의 특성을 파악하기 위하여, 본 연구에서는 한국과 일본에서 건조되어진 대표적인 어선을 한 척씩 선정하여 두 어선의 선형적 특성을 비교하였다. 또한 한국 어선의 선형적 특성들, 즉 일부 대표적인 선형요소들과 이를 제외한 기타의 국부적 선형특성들을 일본어선의 선형을 참고로 보정함으로써 우리나라 어선들의 저항성능을 향상시킬 수 있는 방안에 대하여 연구하였다. 한국어선과 일본어선은 해양환경과 어업의 종류가 다를 뿐만 아니라 관습적인 이유 등으로 선형의 차이가 있게 되며, 이것은 한국 어선이 일본 어선에 비하여 같은 배수량을 가지더라도 배 길이가 짧은 반면 폭이 넓으며 흘수가 얕은 대표적인 선형요소들의 차이로 확인할 수 있다. 이러한 차이를 고려하여, 일본어선들에 대한 유효마력 추정프로그램을 한국어선들에 맞게 보정.개발하는 과정을 통하여 양국 어선의 저항성능 차이를 확인할 수 있었으며, 보정된 프로그램을 이용하여 연구대상의 한국어선에 대한 저항저감효과를 줄 수 있는 선형요소들을 도출함으로써 선형요소들의 변화에 따른 저항성능 효과를 확인할 수 있었다. 그러나 선형요소들의 보정에도 불구하고 한국어선의 저항성능은 여전히 일본어선의 그것보다 떨어짐을 확인하여, 본 연구에서는 대표적인 선형요소들뿐만 아니라 국부적 선형특성 즉, 선수부에서 차인선(chine line) 경사도, 용골의 형상, 선미길이(용골 끝에서 선미단까지의 거리)를 각각 보정해 봄으로써 보다 더 큰 저항성능의 개선효과를 확인하였다. 본 연구결과는 앞으로 저항성능이 우수하면서도 실용 가능한 개량된 한국 어선선형의 개발에 기초적인 자료로서 활용이 가능할 것으로 사료된다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.639-642
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• 2011

이 연구에서는 완전 조립식 교량 하부구조의 비선형해석을 위한 전산플랫폼을 개발하였다. 완전 조립식 교량 하부구조의 비선형거동을 정확하게 파악하고 합리적이면서 경제적인 설계기준의 개발을 위한 자료를 제공하는데 그 목적이 있다. 재료적 비선형성에 대해서는 균열콘크리트에 대한 인장, 압축, 전단모델과 콘크리트 속에 있는 철근모델을 조합하여 고려하였다. 사용된 부착 또는 비부착 텐던요소는 유한요소법에 근거하며 프리스트레스트 콘크리트 부재의 콘크리트와 텐던의 상호작용을 구현할 수 있다. 그리고 접합면요소는 세그먼트 접합부의 비탄성거동을 예측할 수 있다. 제안된 해석기법은 수치예제에 대하여 비선형거동을 비교적 정확하게 예측하였다.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.157-165
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• 2007

In this research, a vertical alignment analysis algorithm was developed. The developed algorithm used acquired data from a vehicle with multiple sensors such as a global positioning system (GPS) an inertial navigation system (INS), and a distance measuring unit (DMI) to collect information about vehicle position and altitude. The vertical alignment analysis algorithm includes the identification of vertical tangent sections, the beginning and ending points of vertical curves, and the calculation of length of vortical curves. Also, the algorithm can help build models for vertical tangent sections and vertical curve sections. In order to verify the algorithm, a field survey was conducted at an actual highway section and the result of the field survey was compared to a highway CAD drawing.

• Computational Structural Engineering
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• v.8 no.3
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• pp.79-89
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• 1995

Two-element plate concept is incorporated into the buckling problem in order to simplify the nonlinear distribution of stress through the thickness of plate. Finite element formulations and programs based upon the Reissner functional and the modified Reissner functional using two-element plate concept are developed for buckling analysis of plates under axial compression. The two programs have been applied to obtain the linear elastic buckling behavior of axially compressed flat plates. Excellent agreement of linear elastic-solution results with exact or approximate solutions of other authors for the same boundary conditions proves the validity of the finite element method using two-element plate theory.

• Proceedings of the KOR-KST Conference
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• 2007.02a
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• pp.306-314
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• 2007

This paper is to develop a model for evaluation of highway alignment design considering the driver's behavior in order to enhance the highway safety. Under the conditions, this research included a new evaluation criteria development and an analysis on how to change evaluation criteria according to roadway alignments, to evaluate safety. The vehicle spacing and speed deviation are suggested as new evaluation index The evaluation criteria model can be used to compare the anticipated safety performance of two or more geometric alternatives for a proposed highway improvement.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.21-40
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• 2003

A traffic accident analysis method was developed and tested based on the highway alignment risk indices using geographic information systems(GIS). Impacts of the highway alignment on traffic accidents have been identified by examining accidents occurred on different alignment conditions and by investigating traffic accident risk indices(TARI). Evaluative criteria are suggested using geometric design elements as an independent variable. Traffic accident rates were forecasted more realistically and objectively by considering the interaction between highway alignment factors and the design consistency. And traffic accident risk indices and risk ratings were suggested based on model estimation results and accident data. Finally, forecasting traffic accident rates, evaluating the level of risk and then visualizing information graphically were combined into one system called risk assessment system by means of GIS. This risk assessment system is expected to play a major role in designing four-lane highways and developing remedies for highway sections susceptible to traffic accidents.

• Journal of the Korea Institute of Building Construction
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• v.11 no.1
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• pp.1-8
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• 2011

Linear scheduling method limits to present works of work breakdown structure as a form of lines and was often developed manually. In other words, linear schedule could not utilize activity, work breakdown structure, and etc. information of network schedule such as CPM(Critical Path Method) and has been used only for reporting or confirming construction master plan. Therefore, it is necessary to develop system which can automatically generating the linear schedule based on the network schedule having many accumulated and useful construction schedule information. Thus, this research has an effort to establish data process model, data flow diagram, and data model in order to make linear schedule. In addition, this research addresses the system solution structure, user interface class diagram and logic diagram, and data type schema. The results of this paper can be used as a preliminary research for developing linear schedule generating system prototype by utilizing the network schedule information.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.1
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• pp.33-45
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• 1995

This paper as a sequel to Kang et al. (1994) describes the development of a three-dimensional nonlinear Galerkin-FEM model. Nonlinear advective terms have been incorporated in a manner used by Lardner and Song (1992), that is, using velocities at given nodes computed with linear Galerkin FEM model. The Proposed model is computationally more efficient than previous nonlinear Galerkin models developed by Owen (1980) and Davies (1980) because the model uses a linear shape function as a basis and, furthermore, the similarity transform technique developed by Kang (1994). Two experiments have been carried out to examine effects of nonlinear terms. One is an experiment of wind-driven current in a rectangular basin (Heaps' basin) and the other is an experiment concerning eddy generation behind a jetty with specified downstream and upstream open boundary conditions. The computed Pattern was found to be in good agreement qualitatively with previous model experiments by Stelling (1984).

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.170-171
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• 2003

비선형 광학은 새로운 광원 개발, 광신호의 전광 고속 처리 같은 분야에 응용 가능하기 때문에 비선형 광학 특성이 좋은 물질의 개발과 정해진 특성을 극대화시킬 수 있는 여러 가지 위상정합 방법의 개발이 진행되고 있다. 우리는 특성이 클 뿐 아니라 만들기 쉽고 제조가격이 싸다는 장점을 갖는 유기 고분자에 대해 2차 비선형 광학 계수를 측정해 보았는데, 단순히 계수의 크기만을 측정하지 않고 계수의 부호도 직접 관찰하여 고분자를 이용한 준위상정합의 가능성을 확인하였다. (중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.432-438
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• 2017

The primary objective of the current work was to develop a standardized retrofit hull form capable of saving energy based on existing vessels. The bow shape of existing vessels was investigated, giving consideration to design draft and speed. Resistance performances were assessed for existing vessels according to operating conditions. Commercial CFD codes and model test materials were used for assessment of effective power. Three retrofit hull forms with minimum resistance were selected given real operating conditions. These vessels were named after customized ready-made hull forms to enable ship owners to make easier choices. The effective power of each vessel was estimated under real operating conditions. Subjects were operated with the lowest draft, and performance for retrofit No. 3 showed an 11-16% improvement in effective power at low speed ranges of 16-18 knots compared to existing vessels. When operated with a middle draft, performance for retrofit No. 3 showed a 6-11% improvement in effective power at low speed ranges compared to existing vessels. When operated with the highest draft, performance for all vessels showed little difference in effective power.