• 산업경영시스템학회지
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• 제43권2호
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• pp.79-86
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• 2020

To make a satisfactory decision regarding project scheduling, a trade-off between the resource-related cost and project duration must be considered. A beneficial method for decision makers is to provide a number of alternative schedules of diverse project duration with minimum resource cost. In view of optimization, the alternative schedules are Pareto sets under multi-objective of project duration and resource cost. Assuming that resource cost is closely related to resource leveling, a heuristic algorithm for resource capacity reduction (HRCR) is developed in this study in order to generate the Pareto sets efficiently. The heuristic is based on the fact that resource leveling can be improved by systematically reducing the resource capacity. Once the reduced resource capacity is given, a schedule with minimum project duration can be obtained by solving a resource-constrained project scheduling problem. In HRCR, VNS (Variable Neighborhood Search) is implemented to solve the resource-constrained project scheduling problem. Extensive experiments to evaluate the HRCR performance are accomplished with standard benchmarking data sets, PSPLIB. Considering 5 resource leveling objective functions, it is shown that HRCR outperforms well-known multi-objective optimization algorithm, SPEA2 (Strength Pareto Evolutionary Algorithm-2), in generating dominant Pareto sets. The number of approximate Pareto optimal also can be extended by modifying weight parameter to reduce resource capacity in HRCR.

• 대한토목학회논문집
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• 제26권1B호
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• pp.27-38
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• 2006

현재 국내의 홍수예보시스템의 예측 모형으로 저류함수모형을 사용하고 있다. 저류함수모형은 계산절차가 간편하고 홍수유출의 비선형성을 고려할 수 있는 방법이므로 선형모형보다 합리적이라고 알려져 있다. 그러나 저류함수모형을 실제 홍수사상에 적용하는데 있어 매개변수를 결정하는 것이 매우 어렵다. 저류함수모형의 매개변수 보정을 모형 운영자의 주관적인 판단아래 시행착오에 의한 수동보정 방법을 사용하여 왔다. 본 논문에서는 홍수통제소에서 사용하고 있는 저류함수 모형의 대표(평균) 매개변수와 시행착오법(Trial & Error Method) 그리고 최적화기법(Optimization Technique)에 의해 보정된 매개변수를 비교 분석하였다. 또한 모의효율을 평가하기 위하여 목적함수별, 보정방법별로 평가지표들을 산정하고 비교 분석하였다. 분석 결과, 최적화기법의 하나인 유전자 알고리즘(Genetic Algorithm)이 목적함수에 따른 변동성이 가장 적었으며, 목적함수로는 SSR(Sum of Squared of Residual)이 가장 적합한 것으로 판단하였다.

• 한국통신학회논문지
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• 제29권6C호
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• pp.842-847
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• 2004

본 논문에서는 낮은 전송률에서 공간적 시간적 해상도를 tradeoff하는 새로운 비디오 코딩 알고리듬을 제안한다. 먼저 영상의 움직임을 측정하여 최적의 frame rate를 선택한다. DCT quantization parameter (QP)는 앞에서 결정된 frame rate와 주어진 bit rate에 따라 결정한다. 마지막으로, 본 논문은 skip된 비디오 영상에 대해 단순하고 효과적인 distortion 측정방법을 제안한다. 실험결과, 제안한 알고리듬이 H.263 TMN5 보다 영상 품질이 2 ㏈ 정도 개선되었다.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.850-856
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• 2009

A new type bi-directional damper using a tuned liquid column damper(TLCD) and a tuned sloshing damper(TSD) is introduced in this study. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with one damper. One of objectives of this study is to derive analytical dynamics to investigate coupled effects due to TLCD and TSD. Another objective is to address the effect of coupled control force due to TLCD and TSD on the dynamic characteristic of the damper based on analytical dynamics. Shaking table test is undertaken to experimentally grasp dynamic characteristics of the damper under white noise excitation. Its dynamic characteristic is expressed by the transfer function from the shaking table acceleration to the control force generated from the damper. Finally, its design parameters are identified based on the coupled dynamics, which include the mass ratio of horizontal liquid column to total liquid for a TLCD, the participation factor of the fundamental liquid sloshing for a TSD and damping ratio for both cases.

• 한국산업융합학회 논문집
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• 제7권3호
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• pp.281-288
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• 2004

The objective of this study is to propose a methodology of the flood runoff analysis in steep mountainous basins and the analysis basin is the Jasa valley basin in Chungju city Analyzing the spatial pattern of the rainfall in 1994. 6 30~7.1, the seasonal rainy front was tied up in the whole central district, and the rainfall center was moving from the northern Chungbuk province to the northern Kyongbuk province and caused heavy storm. Analyzing the temporal pattern with the Huff method, the 52.5% of the rainfall was concentrated on the 3rd quartile. Rainfall frequency analysis is accomplished by five distribution types; 2-parameter Lognomal, 3-parameter Lognomal, Pearson Type III, Log-Pearson Type III and Extremal Type I distribution Rainfall-runoff analysis in Jasa valley basin was made using HEC-HMS model. Jasa valley basin was divided into 3 sub-basins and the analysis point was 3 points{A, B and C point) With the rainfall data measured by the 10 minutes, the flood runoff also was calculated by as many minutes. SCS CN model, Clark UH model and Muskingum routing model in HEC-HMS model were used to simulate the runoff volume using selected rainfall event.

• 임산에너지
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• 제18권2호
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• pp.84-91
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• 1999

The objective of this study was to present creep and the effects of mechano-sorptive deflection of drift pin moment resisting joint between LVL members under changing relative humidity (RH) conditions. The LVL members with steel gusset were jointed by a square pattern of eight injected drift pin. Three diameter drift pins were used to test specimens (6mm, 10mm, and 16mm). The creep test was conducted under two constant loading conditions : one at 30 kgf(840 kgf-cm) and the other at 60 kgf(1680 kgf-cm). The experiment was conducted in an open shed outside. (1)The total rotation creep model of moment resisting joing can be expressed as the sum of the creep of controlled environment (3-parameter model), dimensional change and mechano-sorptive deflection resulting from the variable environment. (2)Mechanosorptive rotation creep is recoverable as moisture content increases during adsorption. Least squares method for linear regression analysis was performed using mechano-sorptive rotation creep as the dependent variable and moisture content as the independent variable. The slope of low moment specimens are compared with those of high moment. This means that low moment condition is more easily affected by changes in humidity than high moment conditions. (3)Although creep deflection is higher for small diameter drift pin than for large diameter drift pin, the shape of creep deflection curves for all specimens is similar.

• 한국멀티미디어학회논문지
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• 제9권8호
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• pp.1000-1009
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• 2006

본 논문에서는 부화소 단위의 적응적인 선형 보간법을 제안한다. 보통의 선형 보간법에 화소 마다 매개변수가 도입되고 이 매개 변수를 최적으로 구하기 위해서 저역 필터와 MMSE (minimum mean square error) 방법을 이용한 일반적인 보간 구조를 제안한다. 또한 제안된 일반적인 적응 선형 보간 구조에서 복잡도를 최소화한 방법을 유도하여 간단한 닫힌 형태의 식으로 제시한다. 기존 방법인 보통의 선형 보간법, 3차 컨볼루션 보간법에 비교하여 주관적으로나 객관적으로 제안된 방법의 우수함을 실험 결과로 알 수 있을 뿐만 아니라 왜곡 거리 선형 보간법(warped distance linear interpolation), 이동 선형 보간법(shifted linear interpolation) 등의 최근 기술과 비교하여도 우수함을 실험결과는 보여준다.

• 한국해양공학회지
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• 제23권6호
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• pp.105-110
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• 2009

The objective of this paper is to investigate the statistical properties of Vickers hardness (HV) for friction welded parts in a Ni-based super alloy (Alloy718). In the case of post weld heat treatment (PWHT) parts, hardness tests were repeated for three different applied loads, 100, 200, and 300 g, with a duration time of 10 seconds. The arithmetic means of the Vickers hardness in heat affected zone (HAZ) materials were smaller than those of the base metal (BM) in all of the applied loads. The coefficient of variation (COV) for the BM and HAZ decreased by increasing the applied load. The probability distribution of the Vickers hardness followed the Weibull distribution well. The distribution of the Vickers hardness was not found to be symmetric. The shape parameter and scale parameter increased by increasing the applied load at both the BM and HAZ.

• 한국멀티미디어학회논문지
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• 제2권2호
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• pp.129-136
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• 1999

특정 이미지에서의 선형적 특정은 이미지를 분석하고 이해하는데 충분한 정보를 제공하기도 한다. 본고에 서는 이미지에서 선형적 특징을 추출하기 위한 신뢰성 있는 방법을 제시한다. 일반적으로 후프 변형 방법은 이러한 선형적 특정을 추출하는 최적의 방법 중의 하나로 인식되어 왔다. 대부분의 후프 기반 방법들은 특정 edge 모델올 선택하고, 인식된 edge 픽셀의 속성을 반영하는 변형식을 활용하여 파라미터 공간에 그 발생빈도 를 기록하는 과정을 거치게 된다. 주로 edge 픽셀의 gradient 크기와 방향이 선형적 특정을 결정하는데 사용되 지만, 본고에서는 그 값틀이 퍼지변수로 활용될 수 있음을 보이고 파라미터 공간에 누적값을 계산하는데 활용한다- 이 방법을 기존의 방법과 비교하기 위하여 에러 측정 방식을 제안하고, 실험을 한 결과, 기존의 방법과 비교하여 우수한 성능을 보인다.

• 한국생산제조학회지
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• 제26권4호
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• pp.351-356
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• 2017

The resistance of printed patterns for electrodes fabricated using printing technology should be minimized. This parameter depends on the pattern width and thickness; however, from the viewpoint of printability, the printed patterns should be printed at the designed width. The resistance of the printed patterns as well as printability is affected by various printing conditions. In this paper, the printing condition is optimized to minimize the resistance of electrodes printed by the roll-to-roll gravure method. This is done by considering the spread ratio of pattern width as a parameter of printability using design experiments. The drying temperature, dryer fan speed, and printing speed are selected as effective factors for the experiment objective. The optimized conditions are obtained and reproducibility test using these demonstrates that the optimized conditions can produce low-resistance electrodes for printability of the pattern width.