• 천문학회보
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• 제44권1호
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• pp.56.1-56.1
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• 2019

The concordance LCDM model has been very successful at reproducing a wide range of observations. However, the nature of its main components, such as dark energy, dark matter, and inflation, are still unkown. Therefore, it is of prime importance to question the underlying hypotheses of the model and tests there prediction. While most constraints have been obtained assuming a LCDM universe, model-independent approaches, which do not make assumptions regarding the model, are a powerful approach. To falsify the LCDM model, I applied model-indepedent methods to the latests available data to test different aspects of the concordance model, such as the FLRW metric, the curvature, dark energy as the cosmological constant, and gravity as general relativity. The Universe is consistent with flat-LCDM with GR. However, at z>1, tensions start to appear, and more data are required.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.154-161
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• 2014

To study and locate partial discharge(PD) and analyze the transient state of power transformer, there is a need for a high frequency model of transformer winding and calculation of its parameters. Due to the high frequency nature of partial discharge phenomenon, there is a need for an accurate model for this frequency range. To attain this goal, a Multi-Conductor Transmission Line (MTL) model is used in this paper for modeling this transformer winding. In order that the MTL model can properly simulate the transformer behavior within a frequency range it is required that its parameters be accurately calculated. In this paper, all the basic parameters of this model are calculated by the use of Finite Element Method (FEM) for a 20kV winding of a distribution transformer. The comparison of the results obtained from this model with the obtained shape of the waves by the application of PD pulse to the winding in laboratory environment shows the validity and accuracy of this model.

• 한국시스템다이내믹스연구
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• 제1권1호
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• pp.57-79
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• 2000

Most model constructs in organization studies are descriptive in nature, and the conclusions relating to the model behavior over time are speculative. The usefulness of System Dynamics as a methodology for modeling and testing dynamic behavioral hypotheses in organizational behavioral studies is presented, and how to construct a System Dynamics model using simulation software(VENSIM) is shown, The well-know March and Simon motivation model is used to demonstrate the step by step application of System Dynamics to model of this type. The dynamic behavior of the model, both transient and steady state, is obtained, Even though the paper has focused on one model in the area of individual behavior, the approach is general and can be applied to other areas of organizational behavior as will. The usefulness of System Dynamics as a methodology for theory building is identified as well.

• 한국조경학회지
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• 제27권4호
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• pp.1-12
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• 1999

This study aims to find basic data for using the quantitative assessment of the sustainability and establishing the systematic index of the planning for local cities to consider the environmentally sound and sustainable development. The research designs to review professional responding to surveys preceded by separate questionnaires and interviews from book reviews, and suggests to make an assessment model of the sustainability for local cities. The research found consequently as follows. Firstly, the research survey items were decides totally 52, grouped 9 assessmental issues and distributed under 4 assessmental domains for the sustainability from the references of book reviews. Secondly, the research result concentrated on the followings from the professional responding to surveys. 1. A most influent factor is the distribution of animals and plants in a nature domain. The next influent factors are the ratio of mass-transportation systems, the numbers of the species of animals and plants, the acreage of conservative forestry, the numbers of reused water resources, and the usage number of water supply, orderly in the nature domain. 2. A most influent factor is the usage number of synthetic detergents in a pollution domain. The next influent factors are the volume of waste water, the number of registered vehicles, the degree of soil pollution, and the charge of development imposition, orderly in the pollution domain. 3. A most influent factor is the acreage of athletic facilities, in an urban domain. the next influent factors are the acreage of recreational facilities, the number and acreage of cultural assets, the number of cultural facilities, the acreage of landscape conservation area, the charge of cultural asset management, orderly in the urban domain. 4. A most influent factor is the number of waste disposal facilities in a participation domain. The next influent factors are the capacity of reused waste, the usage of synthetic detergents, the ratio of waste water disposal, orderly in the participation domain. 5. A most contributed influent domain to the assessment of the sustainability for local cities is the urban domain. The next influent domains are nature domain, participation domain, and pollution domain, orderly in the contribution of the assessment of the sustainability. But, the pollution domain is little relationship with the sustainability. Therefore, it is clear that the abundant greens and the improved level of culture are dominant influences on the sustainabiligy, as like improving the ratio of roadside trees, the acreage of parks, and enlarging the number of cultural facilities.

• 융합정보논문지
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• 제12권3호
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• pp.214-221
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• 2022

자연의 유기적 형태에서 모티브를 얻어 작품을 제작하였으며 다양한 형태 도출을 시도해 보는데 본 연구의 목적이 있다. 연구 방법으로는 국내 학술지 검색을 통해 문헌 조사를 하였고 자연의 유기적인 형태와 디자인 개념을 접목하여 실무에서 무난하게 쓰일 수 있는 헤어 조형 4작품을 제작하였다. 연구결과 첫째, 초승달을 모티브로 조화와 균형의 법칙을 적용하여 작품을 제작하였다. 둘째, 파도를 모티브로 반복의 법칙을 적용하여 물결 웨이브의 흐름을 표현하였다. 셋째, 폭포에서 피여 오르는 아지랑이를 비조화 법칙을 적용하여 표현하였다. 넷째, 떠오르는 해를 강조하여 새로운 시작을 알리는 태양의 이미지를 주고자 하였다. 이에 자연의 유기적 형태는 디자인을 창조하는데 무안한 영감을 준다는 것을 알 수 있었다. 본 연구의 제한점은 마네킹으로만 작품을 제작하여 실제 모델에 제작한 이미지 효과가 동일한 이미지로 연출되는 정확도에 제한점을 두고 후속 연구로는 실제 모델에 활용하여 실용적 활용도를 높일 수 있는 연구가 지속적으로 이루어져야 할 것으로 사료된다.

• 대한기계학회논문집A
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• 제38권11호
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• pp.1245-1256
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• 2014

피로균열 진전거동은 내재적, 외재적 요인에 의하여 시간 경과에 따라 많은 변동을 보인다. 감마과정 모델을 포함하여 연속적, 점진적 그리고 단조롭게 진전하는 피로균열 진전거동의 불확실성을 모사하기 위한 열화모델을 고찰하였다. Lu와 Meeker의 피로시험 자료에 감마과정 모델을 적용하여 시간에 따라 확률적으로 변동하는 피로균열 진전거동을 예측하였다. 피로균열 진전에 관한 상태저하와 수명을 시간에 따라 형상이 변화하는 확률분포 곡선으로 표현하였으며 비대칭도와의 관계로부터 기대수명으로 중위수의 적용이 적절함을 확인하였다. 최적 교체주기와 백분위 수명에 관한 고찰로 감마과정 모델이 예방정비을 위한 정책판단 기준으로 활용할 수 있음을 제시하였다.

• 한국통신학회논문지
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• 제23권8호
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• pp.1926-1940
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• 1998

본 논문은 완전 결합형 ATM 스위치의 성능 분석에 관한 연구결과를 제시하고자 한 내용의 II부로서, 버스티 트래픽 및 비균일 분포에 대한 성능 분석 결과를 포함하고 있다. 사용한 스위치 모델은 ETRI에서 제안한 완전 결합형 ATM 스위치로써 비교적 소규모용으로 설계되었으며 트래픽의 버스트 특성을 효과적으로 홉수하기 위해 2단 버퍼링 구조를 사용하며, 주소 기법은 비트 어드레싱 방식을 사용하여 별도의 기능 블럭 추가없이 멀티캐스팅 기능 구현을 용이하게 하였다. 모의실험을 위해 입력 트래픽 모델은 트래픽의 군집적(bursty) 성질을 포착할 수 있는 IBP 모델과 기존의 트래픽 모델로 사용되어 온 랜덤 트래픽 모델을 고려하였다. 또한 다양한 시나리오 구성을 위해 출력 포트 분포는 균일과 비균일 둘 다를 고려하고 멀티캐스팅 기능도 구현하였다. 본 논문에서는 다양한 환경 하에서 수행한 모의실험 결과를 제시하고 성능 분석을 수행하였다.

• Bulletin of the Korean Chemical Society
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• 제3권3호
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• pp.92-98
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• 1982

Solvolysis reactions of some substituted benzoyl chlorides were studied in ethanol-water, ethanol-trifluoroethanol and methanol-acetonitrile mixtures. Results showed that the reaction proceeds via an $S_N2$ process in which bond formation is more advanced than bond cleavage. Comparison of the two models for predicting transition state variation indicated superior nature of the quantum mechanical model relative to the potential energy surface model.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1990년도 가을 학술발표회 논문집
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• pp.63-68
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• 1990

The nature of fluctuating air pressure inside building was studied by testing a building model in a wind tunnel. The model has a single room and a sin81e window opening. Various opening conditions were tested in both laminar uniform wind and turbulent boundary-layer wind. The RMS and the spectra of the fluctuating internal pressure were measured. The test results support a recent theory which predicts the behavior of internal pressure under high wind based on aerodynamic analysis.

• 대한산업공학회지
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• 제2권1호
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• pp.85-92
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• 1976

In this paper, the employment planning model is developed which is a decision-making model for determining the optimum employment level with respect to varying net manpower requirement for each planing period such that total cost in a planning horizon is minimized. It is constructed as a nonlinear programming model and a dynamic programming model on the basis of studies in the areas of production smoothing and manpower scheduling. Costs for a planning period are categorized into regular wage cost, hiring cost, and overtime cost. The first is a linear function. The other two cost functions are of quadratic nature. The planning horizon of this planning model is intermediate range (five years) for which a fair planning accuracy can be guaranteed. The model considers learning period for each job class. It is simple and an optimum solution can be easily obtained by direct search techniques.