• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.171-177
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• 2018

In 3D printing technologies, many parameters should be optimized for obtaining a part with higher quality. FDM (fused deposition modeling) printer has also diverse parameters to be optimized. Among them, it can be said that nozzle temperature and moving speed of nozzle are fundamental parameters. Thus, it should be preceded to know the optimal combination of the two parameters in the use of FDM 3D printer. In this paper, a new method is proposed to estimate the range of the stable combinations of the two parameters, based on the single line quality. The proposed method was verified by comparing the results between single line printing and multi-layered single line printing. Based on the comparison, it can be said that the proposed method is very meaningful in that it has a simple test approach and can be easily implemented. In addition, it is very helpful to provide the basic data for the optimization of process parameters.

• Water for future
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• v.29 no.5
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• pp.223-233
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• 1996

Daily streamflow model, DAWAST, considering the meteorologic and geographic characteristics of the Korean watersheds has been developed to simulate the daily streamflow with the input data of daily rainfall and pan evaporation. The model is the conceptual one with three sub-models which are optimization, generalization, and regionalization models. The conceptual model consists of three linear reservoirs representing the surface, unsaturated, and saturated soil zones and water balance analysis was carried out in each soil zones on a daily basis. Optimization model calibrates the parameters by optimization technique and is applicable to the watersheds where the daily streamflow data are available Generalization model predicts the parameters by regression equations considering the geographic, soil type, land use, and hydrogeologic characteristics of watershed and is appicable to ungaged medium or small watersheds. Regionalization model cites the parameters from the analysed ones considering river system, latitude and longitude, and is applicable to ungaged large watersheds.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.139-150
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• 2005

Finite element method is applied to the determinations of the two eigenvalues(the elastic critical load and the natural frequence of lateral vibrations) of single story-3 equal bay rectangular frame. The analysis parameters are taper parameter ${\alpha}$ for column, and beam span to column height ratio, ${\beta}$ and second moment area ratio of beam to column, ${\Upsilon}$. Support condition at the column base and sway condition at the column top are also considered in the stability analysis of frame. The changes in the coefficient of eigenvalue are represented by algebraic function of analysis parameter. The coefficients estimated by the proposed algebraic function show good agreement with those determined by finite element method, which suggest the design aid role of the proposed function. By increasing the column axial forces step by step, the corresponding frequencies are also determined, which makes one examine or confirm the relationship suggested by other studies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.383-386
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• 2009

본 연구는 HAZUS에서 제시하고 있는 비보강 조적조 건축물의 구조적 손상상태에 대한 지진취약도함수와 관련하여 층간변위율 및 스펙트럼 변위 등의 매개변수를 평가하고 또한 국내 상황에 적합한 기존 비보강 조적조 건축물의 지진취약도곡선의 도출을 목적으로 하였다. 국내 상황을 고려한 지진피해를 추정하기 위하여 먼저 기존 비보강 조적조 건축물의 현황파악 및 지진취약도함수 산출방법을 분석하였다. 일반적으로 HAZUS에서 제시하고 있는 지진취약도함수는 역량스펙트럼을 변환시킨 가속도-변위응답 스펙트럼법을 기본적으로 사용하는 상황으로 국내 기존 비보강 조적조 건축물에 대한 지진취약도함수 개발을 위하여 Midas GEN Ver.741 구조해석프로그램을 사용하여 실제 23개동의 비보강 조적조 건축물을 대상으로 역량스펙트럼 해석을 수행하였다. 연구결과를 통하여 지진취약도함수의 주요 매개변수인 손상상태별 층간변위율 및 스펙트럼 변위를 제시하였다.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.61-61
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• 2017

본 연구는 경력단절여성의 창업의지를 고취시키기 위해 필요한 변수를 분석하고, 성공적인 창업으로의 연결을 위한 교육 프로그램의 재구성 및 향후 정책이나 사업을 기획함에 있어 이론적 기반을 제공함에 목적을 두고 작성 되었다. 여자의 삶을 살면서 겪게 되는 출산 및 양육은 경력단절을 만드는 주된 이유이며, 이는 개인의 문제 뿐 아니라 저 출산 이라는 또 다른 사회적 문제를 야기 시킨다. 이런 사회적 문제의 해결방안으로 현재 정부는 여성기업의 활동과 여성의 창업을 지원하기 위해 2009년 12월 여성기업지원에 관한 법률을 제정하고, 여성기업 활동 촉진 기본계획을 수립하는 등 여성 창업 촉진을 위해 많은 노력을 하고 있다. 이러한 노력들이 실제 경력단절여성들에게 영향을 미치고 있는지 선행연구를 통해 알아보고, 경력단절여성의 창업의지를 고취시키기 위해 필요한 변수를 분석하여 실증 분석을 통해 관련성을 연구하고자 한다. 경력단절여성의 특성을 파악하여 경력단절 전 보다는 창업에 필요한 소통이 단절되었을 것으로 판단하여 외부의 영향력이 아닌 내부의 개인특성을 중점으로 변수들을 추출하였다는 선행연구와의 차이점이 있고, 일반 예비창업자 혹은 교육학에서 변수로 작용했던 창의성을 경력단절여성을 대상으로 연구하였다는 차이점이 있고, 창업 이라는 교육 커리큘럼에 여성을 대표하는 "감성"을 더해 "여성창업"을 위한 효과적인 교육 및 훈련 프로그램이 만들어 져야 하고, 경력단절여성들이 창업활동을 활발히 할 수 있도록, 일 가정 양립을 위한 제도적인 지원제도가 더욱 많아져 경력단절 여성창업률을 높이려는 노력이 더욱 필요할 것으로 판단된다.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.69-74
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• 2011

It may be an important issue to estimate population of a concerned country. In this study, an appropriate variable was selected to establish a model which fits best the relationship between the night time imagery of DMSP-OLS and population data. Exponential model was selected which was proposed by previous study. Accuracy validation was also performed for each variable extracted from the night time imagery of DMSP-OLS. Consequently, the model showed high accuracy when applied to the area of a certain amount of light was existed. However, further consideration should be necessary when to applied other country or other part of regions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.31-38
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• 2016

In this paper, the deformation-energy curves of the plastic hinges and the vessel bow, which are the major energy dissipation mechanism of a pile protective structures, were estimated, and the parametric study was performed by using those curves to apply the simplified collision model which developed in the previous study. Considered parameters were the mass of slab, the number of piles, the mass of vessel and the collision speed. As results, the difference of energy dissipation mechanism of two pile types (filled and non-filled) were revealed, and the collision behaviors of the protective structures could be tuned by the control of the inertia mass of capping slab. Therefore the simplified collision model can be used in a primary design and optimal design.

• Computational Structural Engineering
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• v.10 no.3
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• pp.195-202
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• 1997

The charateristics of stabilization for stabilized truss unit-structures with cable and truss are investigated in this paper. This unit system is composed of a central post and eight cables, and is connected by hinge joints, and stabilized by self-equilibrated stress field. As this unit structure itself is a statically closed and stabilized system individually, it can be employed to assemble structures with various configurations. In this study, for stabilization of truss structures stabilized by cable tension, the structural concept of unit structures, the range of various geometrical parameters and the relationship of governing parameters about unit systems are explained.

• Computational Structural Engineering
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• v.10 no.3
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• pp.217-223
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• 1997

This paper deals with the basic concepts of sensitivity analysis in a time domain for the transient response of a lumped mass system. Sensitivity analysis methods in thme domain for determining the effects of parameter changes on the response of a dynamic system by external excitation are presented. The parametric sensitivity of a lumped mass system in time domain can be investigated using different types of sensitivity functions, including first order standard and percentage sensitivity functions. These sensitivity functions are determined as a function of partial derivatives of system variables taken with respect to system parameters. In addition, we compared the results of the analytical method by direct method and those of numerical methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.51-56
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• 2005

Ground resistance measurement is an elementary technique for the evaluation of grounding system. There are main environmental factors to consider for correct measurement, but the problem is that it is practically most cases to measure ground resistance unable to know the factors. This paper presents a methodology toward true value of resistance in the unknown circumstance, utilizing the defined term, 'variation rate' of potential difference curve appearing in the distance to a current probe as in the three point fall-of-potential method which comprises the characteristics of environmental factors. This methodology is a induced result from the previous demostrated studies.