• Geomechanics and Engineering
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• 제23권5호
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• pp.455-466
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• 2020

This paper presents analysis of the interaction between tunnel and Qanat with a particular interest for the optimization of Qanat shape using the discrete element code, PFC2D, and the results will be compared with the FEM results of PLAXIS2D. For these concerns, using software PFC2D based on Discrete Element Method (DEM), a model with dimension of 100m ^⁎ 100 m was prepared. A circular tunnel with dimension of 9 m was situated 20 m below the ground surface. Also one Qanat was situated perpendicularly above the tunnel roof. Distance between Qanat center and ground surface was 8 m. Five different shapes for Qanat were selected i.e., square, semi-circular, vertical ellipse, circular and horizontal ellipse. Confining pressure of 5 MPa was applied to the model. The vertical displacement of balls situated in ground surface was picked up to measure the ground subsidence. Also two measuring circles were situated at the tunnel roof and at the Qanat roof to check the vertical displacements. The properties of the alluvial soil of Tehran city are: γ_dry=19 (KN/㎥), E= 750 (kg/㎠), ν=0.35, c=0.3(kg/㎠), φ=34°. In order to validate the DEM results, a comparison between the numerical results (obtained in this study) and analytical and field monitoring have been done. The PFC2D results are compared with the FEM results. The results shows that when Qanat has rectangular shape, the tensile stress concentration at the Qanat corners has maximum value while it has minimum value for vertical ellipse shape. The ground subsidence for Qanat rectangular shape has maximum value while it has minimum value for ellipse shape of Qanat. The vertical displacements at the tunnel roof for Qanat rectangular shape has maximum value while it has minimum value for ellipse shape of Qanat. Historical shape of Qante approved the finding of this research.

• 정보학연구
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• 제4권1호
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• pp.71-79
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• 2001

본 논문에서는 역 전파 신경회로망의 학습파라미터를 발생한 오차에 따라서 유동성 있게 갱신할 수 있고 이 학습알고리즘의 효율을 향상시킬 수 있는 초기연결강도 설정 방법을 제안하였다. 제안한 알고리즘은 국소 점을 벗어날 수 있는 것으로 기대되고, 수렴환경에 알맞은 초기 연결강도 발생을 설정할 수 있다. 모의실험에서는 세 가지의 학습패턴을 가지고 실험하였다. 첫 번째 3-패리티 문제에 대한 학습을 수행하였고, 두 번째는 $7{\times}5$ 알파벳 영문자 폰트에 대한 학습이고 세 번째는 필기체 숫자 및 한글의 기본 획에 적용하였다. 모의실험결과, 제안된 방법은 기존의 표준 역 전파 알고리즘에 비하여 약 27%~57.2%정도 학습효율이 향상됨을 고찰하였다

• 한국식품영양과학회지
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• 제28권4호
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• pp.810-815
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• 1999

The pectinase treatment conditions for clarification of persimmon vinegar were optimized and monitored by response surface methodology. In clarification of persimmon vinegar by pectinase treatment with variations in temperature, time and concentration, coefficients of determinations(R2) of the models were above 0.91(p<0.05) in turbidity, browning color intensity and tannin content. The turbidity of persimmon vinegar was decreased along with an increase of pectinase treatment temperature. The minimum value of turbidity by pectinase treatment was 0.0021(absorbance at 660nm) in 49.38oC of pectinase treatment temperature, 73.08min of pectinase treatment time and 55.57ppm of pectinase concentration. The minimum value of browning color intensity by pectinase treatment was 0.27(absorbance at 660nm) in 48.39oC, 71.74min and 65.69ppm. The minimum value of total tannin contents by pectinase treatment was 43.72mg/100 ml in 40.05oC, 66.02min and 65.26ppm. The optimum conditions of pectinase treatment that satisfies the least common multiple of turbidity, browning color and tannin content were 40~50oC, 60~70min and 55~70ppm.

• 한국농공학회논문집
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• 제49권6호
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• pp.93-101
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• 2007

In general, geotechnical properties have many uncertain aspects, thus probabilistic analysis have been used to consider these aspects. It is, however, quite difficult to select an appropriate target probability for a certain structure or construction process. In this study, minimum expected cost design method based on probabilistic analysis is suggested for design of vertical drains generally used to accelerate consolidation in soft clayey soils. A sensitivity analysis is performed to select the most important uncertain parameters for the design of vertical drains. Monte Carlo simulation is used in sensitivity analysis and probabilistic analysis. Total expected cost, defined as the sum of initial cost and expected additive cost, varies widely with variation of input parameters used in design of vertical drain systems. And probability of failure to get the minimum total expected cost varies under the different design conditions. A minimum value of total expected cost is suggested as a design value in this study. The proposed design concept is applicable to unit construction process because this approach is to consider the uncertainties using probabilistic analysis and uncertainties of geotechnical properties.

• 중환자간호학회지
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• 제12권1호
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• pp.46-56
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• 2019

Purpose : The purpose of this study was to identify minimum data sets for oral mucous integrity-related documentation and to analyze nursing records for oral care. Methods: To identify minimum data sets for oral status, the authors reviewed 26 assessment tools and a practical guideline for oral care. The content validity of the minimum data sets was assessed by three nurse specialists. To map the minimum data sets to nursing records, the authors examined 107 nursing records derived from 44 patients who received chemotherapy or hematopoietic stem cell transplantation in one tertiary hospital. Results: The minimum data sets were 10 elements such as location, mucositis grade, pain, hygiene, dysphagia, exudate, inflammation, difficulty speaking, and moisture. Inflammation contained two value sets: type and color. Mucositis grade, pain, dysphagia and inflammation were recorded well, accounting for a complete mapping rate of 100%. Hygiene (100%) was incompletely mapped, and there were no records for exudate (83.2%), difficulty speaking (99.1%), or moisture (88.8%). Conclusion: This study found that nursing records on oral mucous integrity were not sufficient and could be improved by adopting minimum data sets as identified in this study.

• 한국인터넷방송통신학회논문지
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• 제13권1호
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• pp.143-152
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• 2013

주어진 그래프 G=(V,E), n=|V|, m=|E|에 대해 최소절단을 찾는 연구는 공급처 s와 수요처 t가 주어지지 않은 경우와 주어진 경우로 구분된다. s와 t가 주어지지 않은 무방향 가중 그래프에 대한 Stoer-Wagner 알고리즘은 임의의 정점을 고정시키고 최대 인접 순서로 나열하여 마지막 정점의 절단 값과 마지막 2개 정점을 병합하면서 정점을 축소시키는 방법으로 $\frac{n(n-1)}{2}$회를 수행한다. 또한, s와 t가 주어진 그래프에 대한 Ford-Fulkerson 알고리즘은 증대경로를 탐색하여 절단 간선을 결정한다. 더 이상의 증대 경로가 없으면 절단 간선들의 조합으로 최소절단을 결정해야 한다. 본 논문은 단일 s와 t가 주어진 무방향 가중 그래프에 대해 최대인접 병합과 절단값을 동시에 계산하는 방법으로 n-1회 수행으로 단축시켰다. 또한, Stoer-Wagner 알고리즘은 최소 절단을 기준으로 V=S+T로 양분하지 못할 수 있는데 반해 제안된 알고리즘은 정확히 양분시켰다. 제안된 알고리즘은 Ford-Fulkerson의 증대경로를 찾는 수행횟수보다 많이 수행하지만 수행과정에서 최소절단을 결정하는 장점이 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.69-72
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• 1996

This paper considers a global resolution of kinematic redundancy under inequality constraints as a constrained optimal control. In this formulation, joint limits and obstacles are regarded as state variable inequality constraints, and joint velocity limits as control variable inequality constraints. Necessary and sufficient conditions are derived by using Pontryagin's minimum principle and penalty function method. These conditions leads to a two-point boundary-value problem (TPBVP) with natural, periodic and inequality boundary conditions. In order to solve the TPBVP and to find a global minimum, a numerical algorithm, named two-stage algorithm, is presented. Given initial joint pose, the first stage finds the optimal joint trajectory and its corresponding minimum performance cost. The second stage searches for the optimal initial joint pose with globally minimum cost in the self-motion manifold. The effectiveness of the proposed algorithm is demonstrated through a simulation with a 3-dof planar redundant manipulator.

• Communications for Statistical Applications and Methods
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• 제20권4호
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• pp.311-319
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• 2013

Cooray and Ananda (2005) proposed a composite lognormal-Pareto model to analyze loss payment data in the actuarial and insurance industries. Their model is based on a lognormal density up to an unknown threshold value and a two-parameter Pareto density. In this paper, we implement the minimum density power divergence estimation for the composite lognormal-Pareto density. We compare the performances of the minimum density power divergence estimator (MDPDE) and the maximum likelihood estimator (MLE) by simulations and an example. The minimum density power divergence estimator performs reasonably well against various violations in the distribution. The minimum density power divergence estimator better fits small observations and better resists against extraordinary large observations than the maximum likelihood estimator.

• International Journal of Air-Conditioning and Refrigeration
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• 제14권3호
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• pp.94-101
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• 2006

A theoretical investigation to find thermodynamically optimum design conditions of conduction-cooled Peltier current leads is performed. A Peltier current lead (PCL) is composed of a thermoelectric element (TE), a metallic lead and a high temperature superconductor (HTS) lead in the order of decreasing temperature. Mathematical expressions for the minimum heat flow per unit current crossing the TE-metal interface and the minimum heat flow per unit current from the metal lead to the joint of the metal and the HTS leads are obtained. It is shown that the temperature at the TE -metal interface possesses a unique optimal value that minimizes the heat flow to the joint and that this optimal value depends on the material properties of the TE and the metallic lead but not the joint temperature nor electric current. It is also shown that there exists a unique optimal value for the joint temperature between the metal and the HTS leads that minimizes the sum of the power dissipated by ohmic heating in the current leads and the refrigerator power consumed to cool the lead, for a given length of the HTS.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.366-366
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• 2002

Cloud-to ground lightning and total precipitation over Korean peninsula during the summer monsoon season are studied extensively with a special emphasis on the characteristics of convective precipitation. Ten years (1988-1997) lightning and rainfall data and a temporal and spatial scale of one month and 10$^2$ km$^2$ respectively are used to calculate the monthly number of CG lightning flash count. Monsoonal convective activity is higher over the west coast with maxima at two different regions, one in the northern part which increases nortwestward and the other is at the middle west coast of Korea increasing towards the west coast. East coast represents the minimum value of monsoonal convective activity. In the east coast of Korean peninsula, particularly in the region east of Tae-back mountain, the value of Rain yield, (which is defined as the ratio of total precipitation to CG flash count over a common area), is maximum with an average value of 3$\times$10$^{8}$ kg fl$^{-1}$, while the minimum value of rain yield is occurred in the west of Tae-back mountain, with an average value of 0.8$\times$10$^{8}$ kg fl$^{-1}$. Results show in the west coast stations, nearly 82% of the total rainfall is convective in nature, at the middle of the peninsula 53% of the total rain is convective while in the east coast stations 46% contribution from the convective rain is seen. Kanghwa receives the maximum convective rain while at Ulsan the convective rain is minimum. Correlation coefficient between the total precipitation and CG lightning during the summer monsoon season is 0.54.