• 한국수자원학회논문집
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• 제31권1호
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• pp.59-69
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• 1998

빈도별 홍수량의 지역분석을 위하여 유역의 지형특성을 독립변수로 이용하는 회귀모형을 검정하였다. 그런데 이들 독립변수들간의 상관관계가 존재할 경우 능형회귀모형이 이용되기도 하는 이 방법은 다중공선성 문제를 극복하는데 적합한 방법으로 알려져 있다. 능형회귀모형을 최적화하기 위해서는 조정변수가 포함되는 비용함수를 최소화하여야 한다. 본 연구에서는 이 최적화를 위하여 유전알고리즘을 이용하였다. 유전알고리즘은 자연 생물의 유전 및 진화과정을 모방한 추계학적 탐색방법을 말한다. 이러한 유전알고리즘을 이용하여 지역분석 모형을 검정한 결과 안정된 매개변수의 가중치를 얻을 수 있었다.

• 농약과학회지
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• 제4권2호
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• pp.11-17
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• 2000

분석 대상인 24종 농약을 극성이 다른 캐필러리 칼럼인 DB-17, SPB-608, 및 Ultra-2를 이용하여 전자적압력조절장치(Electronic pressure control, EPC)가 장착된 HP 5890 series II Plus 가스크로마토그래피에서 전자포획검출기로 동시분석법의 최적조건을 모색하였다. 본 실험에서 EPC 시스템의 압력조절기능을 도입하므로써 다음과 같은 분석향상을 얻었다. DB-17, SPB-608, 및 Ultra-2 캐필러리 칼럼에서 EPC 기능없이 동시 분석한 결과 일부 농약들이 분리되지 않았다. 그러나 EPC 시스템의 압력조절 기능을 적용한 결과 vinclozolin과 acetochlor를 제외한 22종 농약 모두 SPB-608 캐필러리 칼럼에서 동시 분석되었다. 또한 농약들의 분리 시간에도 영향을 주어 총 분석시간이 단축되었다. 즉 EPC 시스템 없이 분석한 시간이 $61{\sim}81$분인데 반해 EPC 시스템도입으로 45분으로 단축되었다. 각 농약들에 대한 검출한계는 $0.1{\sim}12.9$ ng/mL 검출되었다.

• Journal of Communications and Networks
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• 제14권4호
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• pp.451-460
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• 2012

Natural disasters often lead to regional failures that can cause network nodes and links co-located in a large geographical area to fail. Novel approaches are required to assess the network vulnerability under such regional failures. In this paper, we investigate the vulnerability of networks by considering the geometric properties of regional failures and network nodes. To evaluate the criticality of node locations and determine the critical areas in a network, we propose the concept of ${\alpha}$-critical-distance with a given failure impact ratio ${\alpha}$, and we formulate two optimization problems based on the concept. By analyzing the geometric properties of the problems, we show that although finding critical nodes or links in a pure graph is a NP-complete problem, the problem of finding critical areas has polynomial time complexity. We propose two algorithms to deal with these problems and analyze their time complexities. Using real city-level Internet topology data, we conducted experiments to compute the ${\alpha}$-critical-distances for different networks. The computational results demonstrate the differences in vulnerability of different networks. The results also indicate that the critical area of a network can be estimated by limiting failure centers on the locations of network nodes. Additionally, we find that with the same impact ratio ${\alpha}$, the topologies examined have larger ${\alpha}$-critical-distances when the network performance is measured using the giant component size instead of the other two metrics. Similar results are obtained when the network performance is measured using the average two terminal reliability and the network efficiency, although computation of the former entails less time complexity than that of the latter.

• 한국국방경영분석학회지
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• 제11권1호
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• pp.87-110
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• 1985

This paper presents optimum policy of water supply distribution of the Osaka Prefecural Waterworks System located in the midwest of Japanese Islands. Owing to the ever increasing demand for water, the Osaka Prefectural Government endeavors to expand potable and industrial water distribution system to satisfy the growing water demand of the constituents under its jurisdiction. In this regard, the paper discusses a problem of establishing an efficient and effective water distribution system. The criteria to be considered are stability of water level at the reservoirs, stability of flow in the network, and the water treatment and distribution cost. These objective functions may be combined to form a multiple objective optimization problem or may be used independently and formulated into single objective optimization problems.

• 한국소음진동공학회논문집
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• 제14권9호
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• pp.827-836
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• 2004

In this paper, we design a robust multi-objective track-following controller that satisfies transient response specifications and diminishes the influence of sinusoidal disturbance. To this end, a robust control problem with the multiple constraints is considered. We show that a sufficient condition satisfying the robust control problem can be expressed by linear matrix inequalities. Finally, the robust track-following controller can be designed by solving an LMI optimization problem. The effectiveness of the proposed controller design method is verified though experiments.

• 상하수도학회지
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• 제34권5호
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• pp.311-321
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• 2020

In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.161-161
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• 2019

Water security issues, stimulated by increasing population and changing climate, are growing and pausing major challenges for water resources managers around the world. Proper utilization, management and distribution of all available water resources is key to sustainable development for achieving water security To alleviate the water shortage, most of the current research on multi-sources combined water supplies depends on an overall generalization of regional water supply systems, which are seldom broken down into the detail required to address specific research objectives. This paper proposes the concept of optimization framework on multi water sources selection. A multi-objective water allocation model with four objective functions is introduced in this paper. Harmony search algorithm is employed to solve the applied model. The objective functions addresses the economic, environmental, and social factors that must be considered for achieving a sustainable water allocation to solve the issue of water security.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.492-495
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• 1990

This paper introduces a path planning technique for a mobile robot in the presence of obstacles. In the technique, workspace is described by regional graph and represented obstacles by the three-layer neural network. And performance cost is defined under consideration both the traveling distance and the safety of a mobile robot. Then a collision-free path is obtained using the neural optimization technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.800-801
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• 2007

본 연구는 지역별 전력수급을 고려한 발전기 보수 계획 수립에 관한 Hybrid Particle Swarm Optimization알고리즘(HPSO) 접근법을 제시하였다. 전체 계통의 예비력 확보에 초점이 맞춰진 기존의 연구에 지역별 예비력을 고려한 제약조건을 추가하였다. 본 연구의 목적함수로는 결정적 신뢰도 지수인 공급 예비율 분산값의 최소화(공급예비율 평활화)를 사용하였으며, IEEE RTS(1996) 계통에서의 사례연구를 수행하여 기존의 PSO알고리즘의 경우와의 비교분석을 통해 제안된 방법의 우수성을 보였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.500-504
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• 2008

The objective of this paper is to evaluate the feasibility of using an optimization model as a effective way to search conjunctive operation scheme to meet two conditions; one is to minimize the electric cost for pumping and another is to meet the water demand for satisfying customers. The feasibility is confirmed as comparing the best combinations of pumps between multi-regional water supply networks from multiple sources which are obtained through an optimization modeling and EPAnet modeling. KModsim model, a network optimization model, was used to determine conjunctive operation scheme in the pipe system. KModsim, based on Lagrangian Relaxation algorithm, is useful for modeling network system and obtaining simultaneously pump combination and water allocation with given input option such as energy unit cost supplying from a source into a consumer, operating pumping combination. This study develops the procedure of determining optimal conjunctive operation scheme with using KModsim model. As a study region, the water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. The EPAnet hydraulic simulation result(Ryu et al, 2007, KSWW) gave input data for optimization model; energy unit price(won/$m^3$), water service available area etc.. It was assured that the combination of pump operation through optimum conjunctive operation is to be optimum scheme to obtain the best economic water allocation with comparison to the hydraulic simulation result such as electric cost and pump combination cases. The results obtained through the study are as follows. First, It was found that a well-allocated water supply scheme, the best combination of pump operation through optimum joint operation, promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. Second, an application of KModSim, a network model, gave the amount of water allocation from each source to a consumer with consideration of economic supply. Finally, in a service area available to supply through conjunctive operation of existing inter-regional water supply networks within short distance, a conjunctive operation is useful for determining each transmission pipeline's service area and maximizing the effectiveness of optimizations in pumping operation time.