• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.207-209
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• 2004

저압간선의 굵기산정시 일반적으로 간이 계산식이 사용되고 있으나 이는 교류 임피던스를 적용한 정식과는 허용 전압강하를 기준으로한 포설거리에서 차이가 있으므로 저압간선의 설계시 보다 정확한 계산을 위해 교류 임피던스를 기준으로한 정식을 사용하여 계산이 이루어져야 한다. 따라서, 본 논문에서는 정식과 간이식에 따른 계산결과와 실측을 통한 전압강하를 비교하여 정확한 전압강하 계산법을 검토하여 보았다.

• Bulletin of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.50-54
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• 1995

선박의 구조설계단계에서 최종붕괴강도를 설계기준으로 삼는 경우는 거의 없으나 최근에 각국 선급에서 최종붕괴강도를 의무적인 설계기준으로 삼기 위해 자체적인 해석법과 설계식을 제시 하고 규정화하는 작업을 진행시키고 있다. [12, 17, 31, 32]. 1994년 ISSC [1]에서도 토론된바와 같이 특히 새로운 구조방식을 가진 선박의 합리적인 구조설계를 위하여는 해상플렛폼의 구조설 계시와 마찬가지로 삼아야 할 것이다. 본고에서는 선각거더의 최종붕괴강도에 대한 해석법과 간이계산식에 관한 연구동향을 문헌조사를 통하여 분석하였다. 그 결과 순수굽힘모멘트가 작용 하는 문제의 경우 최종붕괴강도 해석법은 어느정도 확립되었다고 판단되지만 최종붕괴강도의 간이계산식은 아직도 정도 등의 면에서 개선의 여지가 남아 있다고 생각된다. 앞으로 순수 굽 힘모멘트뿐만아니라 조합하중을 받는 경우와 피로균열을 비롯한 초기구조손상을 가진 노후화된 선박에 대한 최종붕괴강도를 보다 정밀하게 해석하기 위한 해석법의 개발과 간이계산식의 도 출이 필요하다고 사료된다. 또한, 충돌, 좌초, 폭발 등에 기인된 선각거더의 붕괴강도 평가를 위한 해석법의 개발도 앞으로 남은 과제중의 하나이다.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.12
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• pp.65-72
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• 2018

The purpose of this study is to predict vertical illuminance accurately at the design stage of a building without the help of simulation tools. Comparing two well-known vertical illuminance prediction algorithms with measured values, it is verified that the Igawa model is more consistent with the measured values than the Perez model. Using the DIVA program, we simulated the vertical illuminance at 30-degree intervals from south to north, compared with the vertical illuminance calculated with the Igawa model. The result of calculation values were verified from 120 degrees east to 120 degrees west. The vertical illuminance values with each of three shade devices were calculated using the Igawa model, and compared with the vertical illuminance simulated by DIVA program. As a result, all the errors when installing horizontal / vertical / grid shade divices were included in the error standard specified by ASHRAE.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.153-159
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• 2000

This study was carried out to develop a more convenient way to analyze soil texture by hydrometer. Standard Hydrometer Method(SM), in which at least 7 times of reading is required for soil texture analysis, was compared with two other methods named as Soil Clay Fraction Procedure(SCFP) and Simplified for Soil Texture Analysis(SSTA), in which 2 or 3 times of hydrometer reading may be enough for soil texture analysis, respectively. There appeared to be very close correlation(nearly 1.0) between clay contents measured by the above three methods. The clay content measured by SCFP were overestimated by 0~2 percent than those by SM. Textural classes of 28 soil samples determined by SSTA were identical to those by SM. But, textural classes determined by SCFP appeared to be different from those by SM in 4 of 28 soil samples. Because the measurements of particle size in SSTA is made near $2{\mu}m$ diameter, we can save time and labour to measure the clay contents. Therefore, SSTA could be used as a more convenient method to get the same data as SM.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.10
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• pp.854-862
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• 2002

In the previous research, a simplified correlation method was developed as an easy prediction tool for comparing energy use of cooling plants. The purpose of this paper is to test the applicability of this method for economic evaluation with two zones of a 20-story commercial building in Seoul. The results of this method were compared with the DOE-2 simulation and actual measured data. Then, Comparisons of life cycle cost were carried out for three types of cooling plants. Testing of one zone showed good agreement of within 10% error in cooling energy use and within 2% error in LCC. But testing of the other zone indicated that the use of this method were invalid when input variables were used beyond its valid range.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.114-122
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• 2014

An asphalt trackbed is to be adapted in Korea to provide better bearing capacity and stability to the track and a comfortable ride to passengers. The dynamic modulus of Hot Mixed Asphalt(HMA) mixes is a critical design input parameter to determine the thickness of the asphalt trackbed. In this study, impact resonant tests and ultrasonic test methods are designed to obtain the dynamic modulus. These test methods are also verified to check the etffectiveness of constructing a master curve of the dynamic modulus over a wide range of frequencies and temperatures. The test results are compared to the computed dynamic modulus using AASHTO 2002 and the KPRP's proposed model. It can be concluded that the proposed simple test methods are effective to obtain the dynamic moduli of the asphalt mixes for the design of an asphalt trackbed foundation.

• Bulletin of the Society of Naval Architects of Korea
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• v.15 no.1
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• pp.7-9
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• 1978

In this calculation of statical stability of a ship, mechanical integrator was used most popularly and the direct calculation method such as a Barn's wedge method was also adopted in some cases. Both of the above method was developed for manual calculation which include mechanical integration or drafting procedure on body plan. Therefore, the computerization of stability calculation by the above method is very difficult. In this paper a simplified method for stability calculation is suggested, with based on hydrostatic data and immerged wedged characteristics.

• Composites Research
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• v.14 no.1
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• pp.8-14
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• 2001

A simplified method for determining the three mode(I, II, III) components of the strain energy release rate of free-edge delaminations in composite laminates is proposed. The interlaminar stresses are evaluated using the interface moment and the interface shear forces which are obtained from the equilibrium equations at the interface between the adjacent layers. Deformation of an edge-delaminated laminate is analysed by using a generalized quasi-three dimensional classical laminated plate theory. The analysis provides closed-form expression for the three components of the strain energy release rate. The analyses are performed for composite laminates subjected to uniaxial tension, with free-edge delaminations located symmetrically and asymmetrically with respect to the laminate midplane. The analysis results agreed with a finite element solution using the virtual crack closure technique.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.1
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• pp.90-99
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• 2002

The prediction of stress intensity factor(SIF) is one of the most important factors to analyse the propagation behavior of cracks in hull structural members. Up to now, however, simplified prediction method of SIF has not yet been established for the cracks experienced in large complex structures. As a first step to predict crack propagation behavior in a ship structure with very large structural redundancies, simplified SIF prediction formulas for various crack shapes were derived based on the results of the stress analysis under a non-crack condition in this study. The adequacy of the proposed method was then verified in comparison with other experimental and analysis results.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.925-926
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• 2007

전자계 및 열/유동 해석 프로그램을 활용한 수치해석적 방법으로 변압기 외함의 자계손실과 온도상승을 계산하는 경우, 많은 시간이 소요되기 때문에, 설계 또는 고객 요구시 신속한 대응이 어렵다. 따라서 3차원 간이 계산법을 정립하여 신속 정확한 해석적 방법으로 접근할 필요가 있었다, 본 연구에서는 권선의 누설자속에 의해 발생하는 변압기 외함의 자계손실을 계산하고 이에 따른 온도상승을 추정하고자 하였다. 또한, 실제 변압기의 온도상승 시험을 통해 온도상승 계산 결과의 정확성을 검증하고자 하였다.