• 한국농공학회지
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• 제37권E호
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• pp.31-39
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• 1995

Weight minimization for the steel bridge girders using an approximation based optimization technique is presented. To accomplish this, an optimization oriented finite element program is used to achieve continuous weight reduction until the optimum is reached. To reduce computational cost, approximation techniques are adopted during the optimization process. Constraint deletion as well as intermediate design variables and responses are also used for higher qualitv of approximations and for a better convergence rate. Both the reliability and the effectiveness of the underlying optimization method are reviewed.

• 조명전기설비학회논문지
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• 제24권3호
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• pp.39-45
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• 2010

This paper deals with investigation on the spot for grounding systems of buildings based on international standards at construction sites. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for a lightning protection system, continuity of steelwork in reinforced concrete structures, etc. The investigation on the spot was performed by a researcher and engineer with over fifteen years of industry experience all over the country. As a result of the investigation on the spot in 13 buildings, common grounding and structure grounding methods were dominant. The safety improvement methods include installation of equipotential bonding conductors for the connection to the main earthing terminal, equipotential bonding conductors for supplementary bonding, use of Surge Protective Devices (SPD), and safe connections between earthing conductors and the rebar.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.81-85
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• 1998

In the present study, the design method of containment walls is proposed by utilizing an existing site. The selected remedy for the Source Area of Operable Unit 2 at Hill Air Force Base stipulated containment of the pure-phase trichloroethylene contamination. The in-place-mixed wall construction was selected because of the irregular topography, small area of the site, and the requirement to reach depths of greater than 90 feet below ground surface. Bench-scale compatibility studies were performed for the containment wall mix design on three commercial bentonite clays. The samples were subject to screening tests and long-term tests for evaluation of changed soil properties when exposed to the contaminated groundwater.

• Transactions on Control, Automation and Systems Engineering
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• 제1권1호
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• pp.75-86
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• 1999

An air-data estimator for generic air-breathing hypersonic vehicles (AHSVs) is developed and demonstrated with an example vehicle configuration. The AHSV air-data estimation strategy emphasized improvement of the angle of attack estimate accuracy to a degree necessitated by the stringent operational requirements of the air-breathing propulsion. the resulting estimation problem involves highly nonlinear diffusion process (propagation); consequently, significant distortion of a posteriori conditional density is suspected. A simulation based statistical analysis tool is developed to characterize the nonlinear diffusion process. The statistical analysis results indicate that the diffusion process preserves the symmetry and unimodality of initial probability density shape state variables, and provide the basis for applicability of an Extended Kalman Filter (EKF). An EKF is designed for the AHSV air-data system and the air data estimation capabilities are demonstrated.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 춘계학술대회
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• pp.158-159
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• 2018

전 세계적으로 진행 중인 스마트 선박 개발 관련 국내 외 동향을 분석하고, 스마트 선박 특히 자율운항 선박에 필요한 주요 기능을 식별하여, 자율운항 선박을 위한 INS(Integrated Navigation System) 개발에 활용되어 질 수 있는 핵심 기술을 소개한다.

• Earthquakes and Structures
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• 제16권1호
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• pp.29-39
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• 2019

A three-step screening process is presented in this article for selection of consistent earthquake records in which number of suitable ground motions is quickly screened and reduced to a handful number. Records that remain at the end of this screening process considerably reduce the dispersion of structural responses. Then, an effective method is presented for spectral matching and modification of the selected records. Dispersion of structural responses is explored using different statistical measures for each scaling procedure. It is shown that the Uniform Design Method, presented in this study for scaling of earthquake records, results in most cases in the least dispersion measure.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.305-310
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• 2004

소규모 공사는 건축에 있어 가장 기초적이며 근본이 되는 의미를 가진다. 현재 $\ulcorner$건축법$\lrcorner$ 제8조(건축허가)에는 도시계획구역 이외의 지역에 대하여 연면적 $200m^{2}$ 이상이거나 3층 이상인 건축물에는 공사현장에 감리원을 배치하도록 명시하고 있으며 이러한 기준 이하의 건축물에 관해서는 건축신고로 이루어지고 있다. 하지만, 법의 범위를 벗어난 공사현장에서 많은 문제점이 발생하고 있다. 건물의 설계는 전문가인 건축사가 하지 않으며 별도의 감리자도 없이 지역담당 공무원의 현장 방문으로만 관리하고 있는 실정이다. 현장의 기술력은 1980년대의 그것과 크게 다르지 않고, 노동자들의 안전은 더욱 문제가 되고 있으며, 또한 자재선택이 적절치 못해 건축물의 전체적인 품질저하를 초래하기도 한다. 따라서 본 연구에서는 소규모 프로젝트에 대한 현행 법규를 검토하고 소규모 공사현장 책임자와의 설문 및 인터뷰조사를 통하여 현장관리실태를 파악하고 문제점을 분석한다. 그리고 문제점에 대해 많은 현장을 경험한 고령의 기술자를 적극 활용하기 위해 Data Base를 구축하고 온라인 및 오프라인을 통해 공사를 조언 및 관리하는 방안을 제시하는 것을 목적으로 한다.

• Journal of Biosystems Engineering
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• 제36권3호
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• pp.163-170
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• 2011

Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.

• 한국지반공학회지:지반
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• 제12권3호
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• pp.73-82
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• 1996

하중과 저항계수 설계론을 채택하는 극한상태 설계 법이 지반공학분야에도 세계적인 추세로 적용되고 있다. 현재의 허용응력설계법은 논란을 거듭하면서 극한상태 설계법으로 교체되리라 전망된다. 최근에 북미와 유럽에서 시방서로 발간되면서 본격적으로 지반공학설계분야에 관심이 되고 있다. 이러한 세계적인 설계이론을 적절히 비교분석함은 장차 한국의 건설여건에 맞도록 적용하는데 기본요건이라 하겠다. 본 논문에서는 극한상태설계 법을 검토하고 말뚝설계에 하중과 저항계수 설계론을 적용하여 분석하고자 한다.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.411-417
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• 2016

Since the development of Graphic Processing Unit (GPU) in 1999, the development speed of GPUs has become much faster than that of CPUs and currently, the computational power of GPUs exceeds CPUs dozens and hundreds times in terms of decimal calculations and costs much less. Owing to recent technological development of hardwares, general-purpose computing and utilization using GPUs are on the rise. Thus, in this paper, we have identified the elements to be considered for the Smart Grid Security. Focusing on a Performance Improvement of the Basic Algorithm for the Stateful Inspection to Detect DDoS Attacks using CUDA. In the program, we compared the search speeds of GPU against CPU while they search for the suffix trees. For the computation, the system constraints and specifications were made identical during the experiment. We were able to understand from the results of the experiment that the problem-solving capability improves when GPU is used. The other finding was that performance of the system had been enhanced when shared memory was used explicitly instead of a global memory as the volume of data became larger.