• 대한세포병리학회지
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• 제18권2호
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• pp.100-111
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• 2007

Fine needle aspiration (FNA) cytology of breast disease is recognized to be highly accurate and cost effective, especially when this is used in combination with clinical examination and imaging as part of a triple approach. A probabilistic/categorical approach is used for the classification of breast FNA specimens. Criteria are defined from the perspective of the likelihood of making a definitive diagnosis of cancer on excision. This approach is an accurate way of classifying breast FNA specimens, and this can be reliably applied regardless of the level of experience of the pathologist for interpreting the case. When a definitive diagnosis of malignancy is made, the next step is to determining the specific histologic types of the malignancy according to their cytological features. In order to make an accurate diagnosis of carcinoma and for correct typing a tumor, an adequate, correctly sampled aspirate without any other artifacts is required.

• 한국연소학회지
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• 제18권3호
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• pp.54-60
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• 2013

This paper shows a general development process for aircraft gas turbine combustors. As a first step for developing the preliminary combustor design program, several combustor sizing methodologies using reference area concepts are reviewed. There are three ways to determine the reference area; 1) combustion efficiency approach, 2) pressure loss approach, 3) velocity assumption approach. The current study shows the comparisons of the calculated results of combustor reference values from the pressure loss and velocity assumption approaches. Further works are required to add iterative steps in the program using more reasonable values of pressure loss and velocities, and to evaluate the sizing results using data for actual combustor performance and sizes.

• 한국농공학회논문집
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• 제60권2호
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• pp.37-44
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• 2018

Universal soil loss equation (USLE) had been employed to estimate potential soil loss since it was developed from the statewide data measured and collected in the United States. The equation had an origin in average annual soil loss estimation though, it was modified or improved to provide better opportunities of soil loss estimation outside the United States. The equation has five factors, most studies modifying them to adapt regional status were focused on rainfall erosivity factor and cover management factor. While the conservation practice factor (USLE P factor) is to represent distinct features in agricultural fields, it is challenging to find studies regarding the factor improvements. Moreover, the factor is typically defined using slopes. The factor defining approach was suggested in the study, the approach is a step-by-step method allowing USLE P factor definition with given condition. The minimum condition is slope and field location to provide an opportunity for using in any GIS software and to reflect regionally distinct features. If watershed location, slope, crop type, and mulching type on furrows are given, detailed definition of the factors are possible. The approach was developed from field survey in South-Korea, it is expected to be used for potential soil loss using USLE in South-Korea.

• Advances in Computational Design
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• 제2권3호
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• pp.123-141
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• 2017

Solving a system of linear or non-linear equations is required to analyze any kind of structures. There are many ways to solve a system of equations, and they can be classified as implicit and explicit techniques. The explicit methods eliminate round-off errors and use less memory. The dynamic relaxation method (DR) is one of the powerful and simple explicit processes. The important point is that the DR does not require to store the global stiffness matrix, for which it just uses the residual loads vector. In this paper, a new approach to the DR method is expressed. In this approach, the damping, mass and time steps are similar to those of the traditional method of dynamic relaxation. The difference of this proposed method is focused on the method of calculating the damping. The proposed method is expressed such that the time step is constant, damping is equal to zero except in steps with maximum energy and the concentrated damping can be applied to minimize the energy of system in this step. In this condition, the calculation of damping in all steps is not required. Then the volume of computation is reduced. The DR method for form-finding of membrane structures is employed in this paper. The form-finding of the three plans related to the membrane structures with different loading is considered to investigate the efficiency of the proposed method. The numerical results show that the convergence rate based on the proposed method increases in all cases than other methods.

• 대한전자공학회논문지
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• 제26권6호
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• pp.71-78
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• 1989

비선형 시스템의 입출력 관계는 볼테라 급수로 나타낼 수 있으며 그것은 볼테라 커널에 의해 규명될 수 있다. 본 연구는 소수의 볼테라 급수항을 사용하여 계단 입력에 의한 고무의 힘-변위 관계를 모델링하는데 관한 것이다. 무한의 기울기를 가진 계단 입력을 가하여 얻어진 실험결과에서 일정한 압축시의 계단입력에 대한 결과를 예측한다. 비스코일레스틱 재료를 나타내는 현저한 특징중의 하나인 힘-변위 관계를 모델링하기 위해 2차와 3차 볼테라 급수 모델을 사용한다. 3차 볼테라 급수 모델이 2차 볼테라 급수 모델의 결과에 비해 더 좋은 결과가 얻어지고 있다.

• 한국수자원학회논문집
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• 제40권12호
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• pp.969-983
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• 2007

본 연구에서는 도시화로 인해 왜곡된 물순환을 치수, 이수, 수질관리 등의 측면에서 건전화시키기 위해 지속가능한 유역통합관리 계획을 수립하기 위한 10단계의 절차와 적용방법을 개발하여 제시하였으며 이 중 Step 2에 해당하는 문제점 도출 및 우선순위 결정 단계를 수행하였다. 유역의 잠재적인 위험도를 나타내는 홍수피해잠재능(PFD), 건천잠재능(PSD), 수질오염잠재능(PWQD), 유역평가지수(WEI)를 산정하기 위해 다기준 의사결정기법과 지속가능성평가지수 개념을 사용하였다. 사용된 다기준 의사결정 기법들은 복합계획법, 타협계획법, Regime, ELECTRE II, EVAMIX 방법이며 자료의 가용성과 목적(예비타당성, 타당성)에 따라 다르게 사용될 수 있다.

• 대기
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• 제31권1호
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• pp.29-43
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• 2021

In this study, two-step statistical approach including Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) was employed, and main meteorological factors explaining the high-PM2.5 episodes were identified in two regions: Seoul and Busan. We first performed PCA to isolate the Principal Component (PC) that is linear combination of the meteorological variables observed at two levels: surface and 850 hPa level. The employed variables at surface are: temperature (T2m), wind speed, sea level pressure, south-north and west-east wind component and those at 850 hPa upper level variables are: south-north (v850) and west-east (u850) wind component and vertical stability. Secondly we carried out MLR analysis and verified the relationships between PM2.5 daily mean concentration and meteorological PCs. Our two-step statistical approach revealed that in Seoul, dominant factors for influencing the high PM2.5 days are mainly composed of upper wind characteristics in winter including positive u850 and negative v850, indicating that continental (or Siberian) anticyclone had a strong influence. In Busan, however, the dominant factors in explanaining in high PM2.5 concentrations were associated with high T2m and negative u850 in summer. This is suggesting that marine anticyclone had a considerable effect on Busan's high PM2.5 with high temperature which is relevant to the vigorous photochemical secondary generation. Our results of both differences and similarities between two regions derived from only statistical approaches imply the high-PM2.5 episodes in Korea show their own unique characteristics and seasonality which are mostly explainable by two layer (surface and upper) mesoscale meteorological variables.

• Journal of Computing Science and Engineering
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• 제8권2호
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• pp.94-106
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• 2014

Schema matching is widely used in many applications, such as data integration, ontology merging, data warehouse and dataspaces. In this paper, we propose a novel matching technique that is based on the order of attributes appearing in the schema structure of query results. The appearance order embodies the extent of the importance of an attribute for the user examining the query results. The core idea of our approach is to collect statistics about the appearance order of attributes from the query logs, to find correspondences between attributes in the schemas to be matched. As a first step, we employ a matrix to structure the statistics around the appearance order of attributes. Then, two scoring functions are considered to measure the similarity of the collected statistics. Finally, a traditional algorithm is employed to find the mapping with the highest score. Furthermore, our approach can be seen as a complementary member to the family of the existing matchers, and can also be combined with them to obtain more accurate results. We validate our approach with an experimental study, the results of which demonstrate that our approach is effective, and has good performance.

• Interaction and multiscale mechanics
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• 제1권4호
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• pp.449-465
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• 2008

In this paper a general approach for studying the motion of a cantilever beam interacting with a 2D fluid flow is presented. The fluid is solved by a general purpose commercial computational fluid dynamics (CFD) package (FLUENT 6.2), while the structure is managed by means of a dedicated finite element method solver, coded in FLUENT as a user-defined function (UDF). A weak fluid structure interaction coupling scheme is adopted exchanging information at the end of each time step. An arbitrary cantilever beam can be introduced in the CFD mesh with its wetted boundaries specified; the cantilever can also interact with specified rigid and flexible walls through use of a non-linear contact algorithm. After a brief review of relevant scientific contributions, some test cases and application examples are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2108-2111
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• 2005

The mission life of a satellite determines the amount of fuel required on-board, while the total mass requirement limits the fuel to be loaded. Hence, for the design of thruster control loop, not only the satellite pointing accuracy but the saving of fuel is to be considered. In this paper, a two-step fuzzy controller is proposed for the thruster control loop to save fuel consumption. This approach combines requirements for pointing control accuracy with minimum fuel consumption into a fuzzy controller design. To demonstrate this approach, we have designed a fuzzy controller for the Sun point Mode of KOMPSAT-2. The performance of this fuzzy controller design is compared with that of PD controller used for KOMPSAT-2.