• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.138-144
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• 2020

The Army's engineers are carrying out a range of operations using various equipment, of which, artillery unit support is the representative engineering operation field. The main task of the artillery unit is to attack the enemy's center with firepower from the rear of a friendly force. The artillery must move its original position after firing several times to prevent exposure of the shooting position. This paper proposed a mathematical model and heuristic algorithm that can be used to determine the optimal allocation among engineer equipment, the team (work), and position while reflecting the constraints of the construction of an artillery position. The model proposed in this paper derived the optimal solution for the small size problems, but it takes a long time to derive the optimal solution for the problem of equipment placement of the engineer battalion and brigade scale. Although the heuristic suggested in this study does not guarantee the optimal solution, the solution could be obtained in a reasonable amount of time.

• The Journal of the Korea Contents Association
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• v.8 no.5
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• pp.52-60
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• 2008

A simple Time Division Multiplex(TDM) switching system which has been widely in satellite networks provides any size of bandwidth for a number of low bandwidth subscribers by allocating proper number of time slots in a frame. In this paper, we propose a new approach based on graph coloring model for efficient time slot assignment algorithm in contrast to network flow model in previous works. When the frame length of an initial matrix of time slot requests is 2's power, this matrix is divided into two matrices of time slot requests using binary divide and conquer method based on the graph coloring model. This process is continued until resulting matrices of time slot requests are of length one. While the most efficient algorithm proposed in the literature has time complexity of $O(N^{4.5})$, the time complexity of the proposed algorithm is $O(NLlog_2L)$, where N is the number of input/output links and L is the number of time slot alloted to each link in the frame.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.77-90
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• 2002

Network expansion has been an inevitable method for most traffic equilibrium assignments to consider intersection movements such as intersection delays. The drawback of network expansion is that because it dramatically increases network sizes to emulate possible directional movements as corresponding links, not only is complexities for building network amplified, but computational performance is shrunk. This paper Proposes a new variational inequality formulation for a user-optimal traffic equilibrium assignment model to explicitly consider directional delays without building expanded network structures. In the formulation, directional delay functions are directly embedded into the objective function, thus any modification of networks is not required. By applying a vine-based shortest Path algorithm into the diagonalization algorithm to solve the problem, it is additionally demonstrated that various loop-related movements such as U-Turn, P-Turn, etc., which are frequently witnessed near urban intersections, can also be imitated by blocking some turning movements of intersections. The proposed formulation expects to augment computational performance through reduction of network-building complexities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.287-295
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• 2022

As low altitude long-range artillery threat has been strengthened, the development of anti-artillery interception system to protect assets against its attacks will be kicked off. We view the defense of long-range artillery attacks as a typical dynamic weapon target assignment (DWTA) problem. DWTA is a sequential decision process in which decision making under future uncertain attacks affects the subsequent decision processes and its results. These are typical characteristics of Markov decision process (MDP) model. We formulate the problem as a MDP model to examine the assignment policy for the defender. The proximity of the capital of South Korea to North Korea border limits the computation time for its solution to a few second. Within the allowed time interval, it is impossible to compute the exact optimal solution. We apply approximate dynamic programming (ADP) approach to check if ADP approach solve the MDP model within processing time limit. We employ Shoot-Shoot-Look policy as a baseline strategy and compare it with ADP approach for three scenarios. Simulation results show that ADP approach provide better solution than the baseline strategy.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.4
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• pp.1-17
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• 2014

The functions of stocking and releasing in logistics center consist of three major procedure such as receiving, shipping and stock managements. Each process includes various sub-processes which are complicatedly connected with each other. Furthermore, lots of operators execute various tasks in the different sub-processes, simultaneously. It makes difficult to standardize, monitor, and analyze the processes. This paper proposed the quantitative methodology using process mining approach to discover and analyze receiving and shipping processes. For this purpose, the PDA operation log data is analyzed to build a realistic process model. The deduced model has been compared with official process model. In addition, task assignment and social networks analysises are carried out by utilizing process mining tools. Also, it has been proposed how to improve the processes with the analytical simulation model based on the results of process mining.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.324-327
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• 1996

This paper describes the robust controller design methods applied to the problem of an automatic system for tow-vehicle/trailer combinations. This study followed an inverse Linear Quadratic Regulator(LQR) approach which combines pole assignment methods with conventional LOR methods. It overcomes two concerns associated with these separate methods. It overcomes the robustness problems associated with pole placement methods and trial and error required in the application of the LQR problem. Moreover, a Kalman filter is used as the observer, but is modified by using the loop transfer recovery (LTR) technique with modified transmission zero assignment. The proposed inverse LQG,/LTR controllers enhances the forward motion stability and maneuverability of the combination vehicles. At high speeds, where the inherent yaw damping of the vehicle system decreases, the controller operates to maintain an adequate level of yaw damping. At backward moton, both 4WS (2WS tow-vehicle, 2WS trailer) and 6WS (4WS tow-vehicle, 2WS trailer) control laws are proposed by using inverse LQG/LTR method. To evaluate the stability and robustness of the proposed controllers, simulations for both forward and backward motion were conducted using a detailed nonlinear model. The proposed controllers are significantly more robust than the previous controllers and continues to operate effectively in spite of parameter perturbations that would cause previous controllers to enters limit cycles or to loose stability.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1346-1349
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• 2004

In this paper, we have proposed the new link-weight calculating function using for routing decision in WDM networks. The proposed link-weight calculating functions includes following factors those are available wavelengths per link, distance loss, total wavelengths, and limited wavelength conversion. The calculated link-weight is applied into the algorithm of routing decision in order to determine the available lightpath that qualifies user requests. The objective is to improve the performance of wavelengths assignment with fast determining the suitable lightpath by using the proposed link-weights calculating function. The analytical model of WDM switching networks is introduced for numerical analysis. The link-weight calculating function is performed. Finally, the performance of proposed algorithm is displayed with numerical results in term of the blocking probability, the probability that connection requests from users are rejected due to there are no available lightpath to be assigned for them. It is also shown that the blocking probability is varied in depending on the number of available wavelengths and the degree of wavelength conversion. The numerical results also show that the proposed link-weight calculating function is more cost-effective choice for the routing decision in WDM switching networks.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.12
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• pp.1458-1467
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• 1999

VLSI 공정 기술이 발달하면서 이웃한 전선 간의 간격이 점점 더 가까워 지고 있으며, 그에 따라 인접 전선 간의 혼신 문제가 심각해지고 있다. 본 논문에서는 3층 그리드 채널 배선에 적용 가능한 혼신을 최소화시키는 배선층 할당 방법을 제안한다. 이 방법은 선형 의사 불린 최적화 기법에 맞도록 고안되었으며, 적절한 변수 선택 휴리스틱과 상한값 추정 방법을 통하여 최적의 결과를 짧은 시간 안에 찾아낸다. 실험 결과를 통하여, 일반적인 0/1 정수 선형 프로그래밍 기법과 비교하여 성능과 수행시간 면에서 우수함을 보인다. Abstract Current deep-submicron VLSI technology appears to cause crosstalk problem severe since it requires adjacent wires to be placed closer and closer. In this paper, we deal with a horizontal layer assignment problem for three layer HVH channel routing to minimize coupling capacitance, a main source of crosstalk. It is formulated in a 0/1 integer linear programming problem which is then solved by a linear pseudo boolean optimization technique. Experiments show that accurate upper bound estimation technique effectively reduces crosstalk in a reasonable amount of running times.

• Korean Management Science Review
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• v.16 no.1
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• pp.157-171
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• 1999

In a increasingly competitive marketplace, the manufacturing companies have no choice but looking for ways to improve productivity to sustain their competitiveness and survive in the industry. Recently cellular manufacturing has been under discussion as an option to be easily implemented without burdensome capital investment. The objective of cellular manufacturing is to realize many aspects of efficiencies associated with mass production in the less repetitive job-shop production systems. The very first step for cellular manufacturing is to group the sets of parts having similar processing requirements into part families, and the equipment needed to process a particular part family into machine cells. The underlying problem to determine the part and machine assignments to each manufacturing cell is called the cell formation. The purpose of this study is to develop a clustering algorithm based on the neural network approach which overcomes the drawbacks of ART1 algorithm for cell formation problems. In this paper, a generalized learning vector quantization(GLVQ) algorithm was devised in order to transform a 0/1 part-machine assignment matrix into the matrix with diagonal blocks in such a way to increase clustering performance. Furthermore, an assignment problem model and a rearrangement procedure has been embedded to increase efficiency. The performance of the proposed algorithm has been evaluated using data sets adopted by prior studies on cell formation. The proposed algorithm dominates almost all the cell formation reported so far, based on the grouping index($\alpha$ = 0.2). Among 27 cell formation problems investigated, the result by the proposed algorithm was superior in 11, equal 15, and inferior only in 1.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.153-161
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• 2002

다사용자계층 통행배정(Multiple User Class Assignment) 문제란 교통망을 이용하는 통행자들이 이질적인 통행계층으로 구성된 경우, 이들 각 계층의 통행수요를 교통망에 배정하는 문제를 의미한다. 이는 기존 통행 배정모형들이 모든 통행자의 통행특성이 동질적이라고 가정함으로서 발생하는 불합리한 통행배정 결과를 완화시키기 위한 방법이다. 또한, 최근 지능형교통체계(Intelligent Transportation Systems, ITS)사업에서 교통정보제공시스템이 구현될 예정임에 따라, 교통정보를 제공받는 계층과 그렇지 못한 계층간의 영향을 분석하거나 혼잡통행료부과 등과 같은 교통관리전략을 정확히 평가하기 위해서 다사용자계층 통행배정모형에 대한 관심이 증가하고 있다. 그러나, 다사용자계층 통행배정모형의 경우, 사용자간의 상호영향으로 통행비용함수의 1차 편미분행렬(Jacobian matrix)이 비대칭(Asymmetric)이 되어 동등 수리최소화문제(Equivalency mathematical Minimization program)로 구성할 수 없고 또한 수치적으로 풀기가 어렵다는 문제가 있다. 본 연구는 이런 문제점을 극복할 수 있는 모형식과 알고리듬을 제시코자 한다. 본 연구에서 제시된 모형은 2가지 특징이 있다. 먼저, 각 사용자 계층간의 상호영향을 모형내에 반영하며, 기종점쌍간의 통행시간변화에 따른 수요변화를 고려한다는 점이다. 이를 위하여 변동부등모형(Variational Inequality Model. VI)으로 문제를 구성하며, 이에 대한 해석 알고리듬도 제시한다. 또한, 변동부등모형으로 구축된 다사용자계층 모형이 다사용자계층 균형조건과 동일함을 보여주는 동등성조건(Equivalency condition)도 제시한다.