• 한국정보통신학회논문지
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• 제14권9호
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• pp.2016-2022
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• 2010

점들의 집합으로부터 곡선이나 곡면을 구성하는 문제는 기하학적 모델링, 컴퓨터그래픽스, 영상처리 등의 분야에서 중요한 역할을 수행하고 있다. 특히 곡선 재구성 문제는 기존에 존재하는 곡선으로부터 샘플링된 점들로부터 순서를 부여하여 점들을 연결하는 문제이다. 이러한 문제에 대한 대부분의 기존 방법들은 유클리언 거리를 기초로 하고 있기 때문에 자기교차를 가지고 있는 곡선의 재구성 문제를 해결하지 못하고 있는 실정이다. 본 논문에서는 이러한 문제점을 해결하기 위하여 방향도 함께 고려하는 거리를 제안하고, 이를 이용하여 데이터 점들에게 순서를 부여하는 알고리즘을 제안한다. 본 논문에서 제안하는 거리함수는 브라운 운동의 확산 특성을 반영한 것으로서, 다음 점의 위치에 대한 정보를 표준정규분포로 전환함에 의해서 유도되었다. 본 논문의 우수성은 기존의 방법으로는 해결하지 못했던 자기교차 곡선 재구성 문제를 해결할 수 있다는 점이다.

• 한국전산구조공학회논문집
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• 제26권3호
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• pp.183-189
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• 2013

본 논문에서는 불확실성을 확률변수로 가정하고 구조물의 파손기준을 한계상태식(Limit State Equation)으로 정의하였다. 한계상태식을 Fleishman의 3차 다항식으로 근사하고 이론적인 확률 모멘트(Moments)를 계산하였다. Fleishman은 표준정규 분포 확률변수에 대해서만 3차 다항식을 제시하였으나, 본 논문에서는 이를 확장하여 베타, 감마, 균일 분포 등 다양한 확률 변수에 적용하였다. 확률 모멘트를 계산하기 위해서 누률(Cumulants)과 정규화된 한계상태식을 활용하였으며, 피어슨 시스템(Pearson System)을 통해 한계상태식의 확률분포를 근사하였다.

• Structural Engineering and Mechanics
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• 제20권3호
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• pp.313-334
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• 2005

The paper presents a new approach for the analysis of slope stability that is based on the numerical solution of a differential equation, which describes the thrust force distribution within the potential sliding mass. It is based on the evaluation of the thrust force value at the endpoint of the slip line. A coupled approximation of the slip and thrust lines is applied. The model is based on subdivision of the sliding mass into slices that are normal to the slip line and the equilibrium differential equation is obtained as the slice width approaches zero. Opposed to common iterative limit equilibrium procedures the present method is straightforward and gives an estimate of slope stability at the value of the safety factor prescribed in advance by standard requirements. Considering the location of the thrust line within the soil mass above the trial slip line eliminates the possible development of a tensile thrust force in the stable and critical states of the slope. The location of the upper boundary point of the thrust line is determined by the equilibrium of the upper triangular slice. The method can be applied to any smooth shape of a slip line, i.e., to a slip line without break points. An approximation of the slip and thrust lines by quadratic parabolas is used in the numerical examples for a series of slopes.

• 한국해양공학회지
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• 제13권3B호
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• pp.29-37
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• 1999

Ventilation of the marine engine room is very important for the health of the workers as well as the normal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-${\epsilon}$ model was carried out. In the present study, the marine engine room is separated to two floors with porus horizontal partition and considered as a closed space with a heat source and forced ventilation ducts. The porosity of horizontal partition is found to be important. For the engine room with 2 supply ports & 2 exhaust ports, the increasing of the porosity of horizontal partition is effective to reduce the recirculation flow zone in the second floor. When the engine room is ventilated with three supply air ports & one exhaust port, the increasing of the porosity of horizontal partition is effective to reduce the recirculating flow zone in the exhaust air area, but there is a possibility of local extreme heating at the lower side of engine near bottom.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.319-326
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• 2004

Uncertainty is inevitably involved in rock slope engineering since the rock masses are formed by natural process and subsequently the geotechnical characteristics of rock masses cannot be exactly obtained. Therefore the reliability analysis method has been suggested to deal properly with uncertainty. The reliability analysis method can be divided into level I, II and III on the basis of the approach for consideration of random variable and probability density function of reliability function. The level II approach, which is focused in this study, assumes the probability density function of random variables as normal distribution and evaluates the probability of failure with statistical moments such as mean and standard deviation. This method has the advantage that can be used the problem which the Monte Carlo simulation approach cannot be applied since the complete information on the random variables are not available. In this study, the analysis results of level II reliability approach compared with the analysis results of level III approach to verify the appropriateness of the level II approach. In addition, the results are compared with the results of the deterministic analysis.

• 한국간호교육학회지
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• 제10권2호
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• pp.297-307
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• 2004

This study aims to identify the types and type-specific characteristics of subjectivity on complementary alternative therapy of nursing students using Q-methodology and to provide them as basic materials for nursing education. Q-methodology provides a scientific method for identifying perception structures that exist within certain individuals or groups. Thirty C college nursing students' classified 35 selected Q-statements into 9 points standard, according to the level of agreement or disagreement by forced normal distribution. The collected data was analyzed by using a QUNAL PC program. Resultingly, the attitude of nursing students regarding complementary alternative therapy was divided into three types. Type 1 is positive recognition. The students who think the therapy contributes to maintaining and improving health, and is a way to protect human body and improve welfare by enhancing immunity. Type 2 is objective acceptance. The students who think the complementary alternative therapy is effective when it is properly used for specific constitutions in discussion with medical teams after its effects are scientifically reviewed. Type 3 is popularity consideration. The students who put focus on its popular use and regard the therapy as very useful for not only patients but also ordinary healthy people because it is based on the natural and human approach. In conclusion, proposed are studies on influence factor of nursing students' awareness about the complementary alternative therapy and reviews on the effects of the complementary alternative therapy that is applied as nursing intervention.

• 한국해양공학회지
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• 제27권4호
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• pp.83-89
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• 2013

A numerical scheme based on a mode superposition method is presented for the dynamic response analysis of a top-tensioned riser (TTR) under sheared current loads. The natural frequencies and mode shapes of the TTR have been calculated analytically for a beam with a slowly varying tension and pinned-pinned boundary conditions at the top and bottom ends. The lift coefficients and corresponding amplitudes used to estimate the vortex-induced modal force and damping for each mode were predicted via iterative calculations based on the input and output power balancing concept. Here, the power-in regions were controlled by the normal distribution function, for which the center was coincident with the lock -in location by local vortex-shedding, and the range was defined by the constant standard deviation for the reduced velocity by the local current speed. Finally, dynamic responses such as root-mean-squared displacement and stress were calculated using the mode superposition technique. In order to verify the presented scheme, a numerical calculation was performed for a TTR under an arbitrary linearly sheared current and linearly varying tension. A comparison with the results of the existing software showed that the presented scheme could give reliable and feasible solutions. Case studies were performed to investigate the effects of various current loads and tensions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1526-1530
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• 2007

In this study, the chukwookee data were evaluated by applying that for the historical rainfall frequency analysis. To derive a two parameter log-normal distribution by using historical data and modern data, censored data MLE and binomial censored data MLE were applied. As a result, we found that both average and standard deviation were all estimated smaller with chukwookee data then those with only modern data. This indicates that rather big events rarely happens during the period of chukwookee data then during the modern period. The frequency analysis results using the parameters estimated were also similar to those expected. The point to be noticed is that the rainfall quantiles estimated by both methods were similar, especially for the 99% threshold. This result indicates that the historical document records like the annals of Chosun dynasty could be valuable and effective for the frequency analysis. This also means the extension of data available for frequency analysis.

• 패션비즈니스
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• 제11권2호
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• pp.155-171
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• 2007

This research aims to present the corresponding dimensions of China men's clothes on the basis of size specification of Korea men's suits. The results of this study, with the cooperation of Sejung Company exporting men's clothes to Ningbo City, Zhejiang Province in China, are as follows: 1. Based on the drop standard of KS K 0050, the body types of Chinese men in their 20s were classified. A body types were 55.77%, Y body types were 32.16%, B body types were 11.55% and BB body types were 1.51%. 2. According to the criteria of ready-made dimensions of normal body type suggested in Korea Standards, and in consideration of the basic distribution reality of body dimensions, representative 5 sizes were selected. 3. Research jackets by different sizes were produced and went through wearing tests. The means of 1st wearing test were 3.86, 4.09, 4.09, 3.57, and 3.69. The mean of 2nd wearing test of 88-73-170 size was 4.32. 4. The corresponding size specification of China men's clothes based on those of Korea men's suits were presented here, showing product sizes and physical items in detail.

• 설비공학논문집
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• 제23권11호
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• pp.705-710
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• 2011

Fault detection has to be proceeded by steady state filtering to get rid of transient effect associated with thermal capacity. Coefficient of variance (COV), ratio of standard deviation devided by moving average, was employed as steady-state filter. Engine speed and refrigerant pressures were selected as parameters representing system dynamics. The filtered values were registered as members of steady-state DB. They were found to show good functional relationship with ambient temperature. The relationship was fitted with a second order polynomial and the distribution bounds of the data around the fitted curve were expressed by visual inspection because of varying average and random data interval. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the fault-free one. To make such isolation reliable, tests to construct good DB should be designed in a systematic way.