• 한국CDE학회논문집
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• 제19권1호
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• pp.41-49
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• 2014

For the reuse of the existing 3D block model of a ship, we analyze the hull modeling process using AVEVA Marine which is a representative CAD (Computer-Aided Design) system for the shipbuilding. In the AVEVA Marine environment where the design engineer makes 3D model on the 2D view that is so-called 2.5D, it cannot be possible to copy to reuse the block model just simply copying the 3D feature model itself like in the general mechanical CAD system or Smart Marine 3D which are on the basis of the 3D model representation. In this paper, we analyze the scheme file where the 3D model is defined in AVEVA Marine so that we develop the program for the block copy and the translation using this scheme file. It is significant that this program can be immediately available as a real-world application on the AVEVA Marine environment.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.903-908
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• 2006

Building energy simulation has become a useful tool for predicting cooling, heating and air-conditioning loads for facilities. It is important to provide building energy performances feed back to the mechanical and electrical system operator and engineer for energy conservation and maintenance of building. From this research, we set up the typical weather data of location, basic description of building, geometric modelling data and the specification of Installed primary HVAC system for establishing the simulation model about energy consuming that take place in multipurpose building complex. The simulation tool of building energy - EnergyPlus (DOE and BLAST based simulation S/W), it has been used and accomplished calculations and analyses for evaluating the effect of the system types and operating condition of central HVAC plant on the building energy consumption. In this paper, we offer comparison and simultaneous results those involve electricity consumption pattern and amount between actual operation versus EnergyPlus simulation to the object building during summer season.

• Computers and Concrete
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• 제31권5호
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• pp.371-384
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• 2023

Precast roofing systems employing prestressed elements often serve as smart structural solutions for the construction of industrial buildings. The precast concrete elements usually employed are highly engineered, and often consist in thin-walled members, characterised by a complex behaviour in fire. The present study was carried out after a fire event damaged a precast industrial building made with prestressed beam and roof elements, and non-prestressed curved barrel vault elements interposed in between the spaced roof elements. As a consequence of the exposure to the fire, the main elements were found standing, although some locally damaged and distorted, and the local collapse of few curved barrel vault elements was observed in one edge row only. In order to understand and interpret the observed structural performance of the roof system under fire, a full fire safety engineering process was carried out according to the following steps: (a) realistic temperature-time curves acting on the structural elements were simulated through computational fluid dynamics, (b) temperature distribution within the concrete elements was obtained with non-linear thermal analysis in variable regime, (c) strength and deformation of the concrete elements were checked with non-linear thermal-mechanical analysis. The analysis of the results allowed to identify the causes of the local collapses occurred, attributable to the distortion caused by temperature to the elements causing loss of support in early fire stage rather than to the material strength reduction due to the progressive exposure of the elements to fire. Finally, practical hints are provided to avoid such a phenomenon to occur when designing similar structures.

• 대한기계학회논문집B
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• 제36권3호
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• pp.351-361
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• 2012

슬관절 내반슬과 외반슬의 부정정렬을 교정하는 방법 중 대표적인 수술법이 근위경골절골술이다. 개방형 쐐기 근위경골절골술(OWHTO)의 경우 근위비골 인접부의 경골외측 비골신경을 손상시킬 우려가 없고, 수술도중 교정각의 개방 정도를 임의대로 조절 변경 가능한 장점으로 최근 선호되고 있다. 그러나 술후 관상면에서의 외반 및 내반 교정은 바르게 이루어지는 반면, 시상면에서는 수술자가 의도하지 않은 경골내측고평부의 후방경사각(PSA) 변화가 발생한다는 문제점이 있다. 저자들은 이와 같은 문제의 극복을 위해 Computer Assisted Surgery를 이용한 근위경골절골술 기법을 자체적으로 개발하였고, 근위경골부의 CT 이미지 3차원 재건과 컴퓨터를 이용한 가상절골술을 수행하였다. 또한 술후에도 후방경사각(PSA)이 변화하지 않는 수술기법에 대해 제시하였다. 본 연구결과는 환자고유의 전내측피질골 경사각(ACOA)과 후방경사각(PSA)의 명확한 관계성에 대해 제시해줄 것이며 환자마다 다른 최적의 후방경사각 결정법에 대해 제시해 줄 것으로 판단된다.

• 토지주택연구
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• 제2권2호
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• pp.195-204
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• 2011

철근콘크리트 건축물에 중장비를 탑재하여 해체작업을 시행할 때, 중장비와 철거잔재의 중량은 건축물을 설계할 당시에 고려하지 못한 하중으로 작용한다. 그러나 우리나라 해체 현장에서는 건축물의 안전성에 대한 구조전문가의 검토 없이, 현장 관리자나 작업자의 경험에 의하여 중장비 탑재와 해체작업이 이루어지고 있어 작업 중에 건축물이 붕괴하거나 중장비가 추락하는 사례도 발생하고 있다. 따라서 해체공사 시행 과정에서 해체 대상 건축물의 구조안전성을 평가할 수 있는 평가기법과 구조부재가 부담할 수 있는 적정 장비중량에 대한 기준 마련이 시급한 실정이다. 이 논문에서는 기계해체 현장에 대한 방문조사와 작업근로자에 대한 설문조사를 통해 해체 대상 건축물의 안전성 평가에 필요한 철거잔재 하중, 하중계수, 강도감소계수, 작업하중 등을 제안하였다. 해체 현황을 고려한 구조물의 해석과 부재(슬래브, 보)의 적절한 안전성 평가방법을 제시하였으며, RC 슬래브와 RC 보의 제원에 따라 양중 가능한 중장비의 중량을 제시하였다. 이 연구에서 제안한 해체구조물의 안전성 평가기법과 중장비 탑재 등급은 해체대상 구조부재의 성능을 합리적으로 평가하고, 적정한 장비운영을 통한 해체작업의 효율성과 안전성을 향상하는 데 유용하게 활용될 수 있을 것으로 사료된다.

• Journal of Biosystems Engineering
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• 제26권6호
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• pp.563-570
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• 2001

To develop a stalk detaching system the effect of shape factor of red pepper affecting the performance of unfolding, arranging and cutting was analysed. The obtained results are as follows : By cutting experiment, it was found that the bending of stalk affected the cutting rate of stalk, and that the bending of body increased the amount of peppers that were expelled from the cutting guide by conveying brush. The ratios, 'bending length of a body/body length'and 'bending length of a stalk/stalk length', could be used as criteria far abnormality of body and stalk of peppers, respectively. As a result of experiment, it was concluded that mechanical treatment would be difficult for the peppers with indexes greater than 0.4 and 0.3 fur body bending and stack bending. respectively. So, these indexes were used as criteria for distinguishing abnormality from normality of peppers. In the unfolding unit, conveyance of peppers was impossible for both of normal and abnormal ones at the inclination angle of 10°, especially, at the frequency of 8.3 Hz peppers maintained stationary state. At the inclination angle of 20°, both of normal and abnormal peppers showed similar tendencies, but abnormal ones showed an accumulation trend gradually with increased feeding speed. In the arranging unit, conveyance of peppers was almost impossible for both of normal and abnormal ones at the inclination angle of 20°, showing almost no difference between the conveyances of normal and abnormal ones. In the case of the inclination angle of 30°, at the condition of the feeding speeds and frequency corresponding 0.06 m/s, 0.08 m/s and 8.3 Hz, respectively, the passing time of the abnormal peppers on the arranging plate increased rapidly.

• 마이크로전자및패키징학회지
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• 제21권3호
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• pp.7-17
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• 2014

Power electronics modules are semiconductor components that are widely used in airplanes, trains, automobiles, and energy generation and conversion facilities. In particular, insulated gate bipolar transistors(IGBT) have been widely utilized in high power and fast switching applications for power management including power supplies, uninterruptible power systems, and AC/DC converters. In these days, IGBT are the predominant power semiconductors for high current applications in electrical and hybrid vehicles application. In these application environments, the physical conditions are often severe with strong electric currents, high voltage, high temperature, high humidity, and vibrations. Therefore, IGBT module packages involves a number of challenges for the design engineer in terms of reliability. Thermal and thermal-mechanical management are critical for power electronics modules. The failure mechanisms that limit the number of power cycles are caused by the coefficient of thermal expansion mismatch between the materials used in the IGBT modules. All interfaces in the module could be locations for potential failures. Therefore, a proper thermal design where the temperature does not exceed an allowable limit of the devices has been a key factor in developing IGBT modules. In this paper, we discussed the effects of various package materials on heat dissipation and thermal management, as well as recent technology of the new package materials.

• Advances in concrete construction
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• 제2권4호
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• pp.249-259
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• 2014

Mortar is a masonry product which is matrix of concrete. It consists of binder and fine aggregate and moreover, it is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The purpose of this research is to investigate the compressive strength and tensile strength of mortar, which are important mechanical properties, by replacing the cement and sand by stone dust. Moreover, to minimize the increasing demand of cement and sand, checking of appropriateness of stone dust as a construction material is necessary to ensure both solid waste minimization and recovery by exchanging stone dust with cement and sand. Stone dust passing by No. 200 sieve, is used as cement replacing material and retained by No. 100 sieve is used for sand replacement. Sand was replaced by stone dust of 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by weight of sand while cement was replaced by stone dust of 3%, 5%, and 7% by weight of cement. Test result indicates that, compressive strength of specimen mix with 35% of sand replacing stone dust and 3% of cement replacing stone dust increases 21.33% and 22.76% respectively than the normal mortar specimen at 7 and 28 days while for tensile it increases up to 13.47%. At the end, optimum dose was selected and crack analysis as well as discussion also included.

• 공학교육연구
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• 제17권4호
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• pp.87-94
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• 2014

이 연구는 공학교육 관련 문헌, 교육과정, 교육표준 등의 분석을 통하여 우리나라의 초등 및 중학교 수준의 공학교육을 정의하고, 공학교육 내용의 유형을 분석하고, 공학교육 내용표준을 개발하여 제안하였다. 공학 및 공학교육의 개념을 과학, 기술학, 공학의 어원적, 학문적, 방법적 차이에 따른 분석 및 조사에 근거하여 규정하였다. 공학교육 내용의 유형은 절차적 과정, 분야별 개념 및 지식, 과정과 지식을 융합 유형의 세 가지로 조사되었다. 공학교육 내용표준은 '공학 및 기술과 사회' '제품과 제조' '공학을 통한 문제해결' '공학기술시스템'의 네 개 대범주와 그에 따른 하위 요소로 개발하였다. 공학교육의 개념적 정의, 교육내용의 유형 및 내용표준은 초등 및 중학교 수준에서 공학교육을 제공하고, 비정규 교과로서 정규 교과와 연결하여 교육내용을 재구성하는 준거로 활용할 수 있을 것이다. 그리고 예비교사 교육 및 현직 교사의 공학교육 연수를 위한 기초 자료로 활용할 수 있을 것이다.

• 한국건설관리학회논문집
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• 제16권2호
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• pp.54-64
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• 2015

최근 건설산업의 환경변화에 따라 전문건설업체 종사자의 업무수행능력 향상을 통한 업체 경쟁력 강화가 요구되고 있다. 이에 본 연구는 전문건설업체 종사자의 능력향상에 가장 효율적인 방법이 교육이라는 점을 인식하고, 이들을 대상으로 한 효과적인 교육, 나아가 맞춤형 교육 프로그램 개발에 기초자료로 활용될 수 있는 직무별 경력별 업무수행수준 분석과 필요역량요인을 파악하기 위한 목적으로 수행되었다. 이를 위해 전문건설업체의 대표, 현장소장, 공사담당, 공무담당, 자재/노무담당, 안전담당 등을 대상으로 설문조사를 실시한 후, 이들의 업무부담수준과 업무수행 능력수준비 등 업무수준을 분석하였으며, 직무별 필요역량요인을 파악하였다. 본 연구의 분석결과를 통해 향후 전문건설업체 종사자의 직무별 경력별 특성을 반영한 수요자 중심의 맞춤형 교육이 가능 할 것으로 판단된다.