• 대한산업공학회지
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• 제39권4호
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• pp.253-259
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• 2013

Investment scenarios in the transportation network design problem usually contain installation or expansion of multi-mode transportation links. When one applies the mode choice analysis and traffic assignment sequentially for each investment scenario, it is possible that the travel impedance used in the mode choice analysis is different from the user equilibrium cost of the traffic assignment step. Therefore, to estimate the travel impedance and mode choice accurately, one needs to develop a combined model for the mode choice and traffic assignment. In this paper, we derive the inverse demand and the excess demand functions for the multi-mode multinomial logit mode choice function and develop a combined model for the multi-mode variable demand traffic assignment problem. Using data from the regional O/D and network data provided by the KTDB, we compared the performance of the partial linearization algorithm with the Frank-Wolfe algorithm applied to the excess demand model and with the sequential heuristic procedures.

• IEIE Transactions on Smart Processing and Computing
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• 제6권3호
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• pp.151-157
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• 2017

Management optimization is very important in tourism, especially when it is related to productivity. One of the problems in management optimization is tour guide assignment. Well-arranged tour guide assignment will increase productivity while maintaining service quality. A cellular genetic algorithm is one of the methods that can be used to solve this problem. Furthermore, previous study has shown that a cellular dimension increase can lead to promising benefits for certain problems. The objective of this research is to give a clear understanding of the advantages of increasing cellular dimensionality on the tour guide assignment problem by using a cellular genetic algorithm.

• 산업공학
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• 제19권2호
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• pp.160-167
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• 2006

It is a crucial managerial issue how to manage assembly blocks at shipyard. Based on the project experience in Hyundai Heavy Industries, this study points out the difficulties on the block stockyard operations, formalizes the JIBUN (location) assignment problem for assembly blocks, and develops the JIBUN (location) assignment algorithm whose purpose is to reduce the number of unproductive block moves. Through simulation experiments for various situations, this study demonstrates the usefulness of JIBUN (location) assignment algorithm. In addition, this study examines the impacts of block move sequence rules and of block stockyard layouts on the block stockyard operations.

• 지능정보연구
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• 제6권1호
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• pp.113-128
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• 2000

This paper presents a first year report of an ongoing multi-year project to develop a systolic parallel simulation system for dynamic traffic assignment. The fundamental approach to the simulation is systolic parallel processing based on autonomous agent modeling. Agents continuously act on their own initiatives and access to database to get the status of the simulation world. Various agents are defined in order to populate the simulation world. In particular existing modls and algorithm were incorporated in designing the behavior of relevant agents such as car-following model headway distribution Frank-Wolf algorithm and so on. Simulation is based on predetermined routes between centroids that are computed off-line by a conventional optimal path-finding algorithm. Iterating the cycles of optimization-then-simulation the proposed system will provide a realistic and valuable traffic assignment. Gangnum-Gu district in Seoul is selected for the target are for the modeling. It is expected that realtime traffic assignment services can be provided on the internet within 3 years.

• International Journal of Control, Automation, and Systems
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• 제4권5호
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• pp.601-614
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• 2006

In this paper, a study on task assignment strategies for a complex real-time network system is presented. Firstly, two task assignment strategies are proposed to improve previous strategies. The proposed strategies assign tasks with meeting end-to-end real-time constraints, and also with optimizing system utilization through period modulation of the tasks. Consequently, the strategies aim at the optimizationto optimize of system performance with while still meeting real-time constraints. The proposed task assignment strategies are devised using the genetic algorithmswith heuristic real-time constraints in the generation of new populations. The strategies are differentiated by the optimization method of the two objectives-meeting end-to-end real-time constraints and optimizing system utilization: the first one has sequential genetic algorithm routines for the objectives, and the second one has one multiple objective genetic algorithm routine to find a Pareto solution. Secondly, the performances of the proposed strategies and a well-known existing task assignment strategy using the BnB(Branch and Bound) optimization are compared with one other through some simulation tests. Through the comparison of the simulation results, the most adequate task assignment strategies are proposed for some as system requirements-: the optimization of system utilization, the maximization of running tasktasks, and the minimization of the number of network node nodesnumber for a network system.

• 인터넷정보학회논문지
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• 제9권1호
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• pp.55-67
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• 2008

본 논문에서는 코드 최적화를 위하여 계산적으로나 수명적으로 제한이 없는 배정문 모션 알고리즘을 제안한다. 이 알고리즘은 지나친 레지스터의 사용을 막기 위하여 불필요한 코드 모션을 억제한다. 본 논문은 최종 최적화단계가 추가된 배정문 모션 알고리즘을 제안한다. 또한 기존 알고리즘의 술어의 의미가 명확하지 않은 것을 개선하였고 노드 단위 분석과 명령어 단위 분석을 혼용했기 때문에 발생하는 모호함도 개선하였다. 따라서 제안한 알고리즘은 불필요하게 중복된 수식이나 배정문의 수행을 피하게 함으로써, 프로그램의 불필요한 재계산이나 재실행을 하지 않게 하여 프로그램의 능률 및 실행시간을 향상시킨다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1884-1903
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• 2019

Device-to-Device (D2D) communications can provide proximity based services in the future 5G cellular networks. It allows short range communication in a limited area with the advantages of power saving, high data rate and traffic offloading. However, D2D communications may reuse the licensed channels with cellular communications and potentially result in critical interferences to nearby devices. To control the interference and improve network throughput in overlaid D2D cellular networks, a novel channel assignment approach is proposed in this paper. First, we characterize the performance of devices by using Poisson point process model. Then, we convert the throughput maximization problem into an optimal spectrum allocation problem with signal to interference plus noise ratio constraints and solve it, i.e., assigning appropriate fractions of channels to cellular communications and D2D communications. In order to mitigate the interferences between D2D devices, a cluster-based multi-channel assignment algorithm is proposed. The algorithm first cluster D2D communications into clusters to reduce the problem scale. After that, a multi-channel assignment algorithm is proposed to mitigate critical interferences among nearby devices for each D2D cluster individually. The simulation analysis conforms that the proposed algorithm can greatly increase system throughput.

• 산업기술연구
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• 제22권B호
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• pp.71-78
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• 2002

The objective of this paper is to develop an efficient genetic algorithm (GA) to find a channel assignment method for minimum interference among the channels within reasonable time. The series of specific channel number is used as a representation of chromosome. We use minimum-channel-distance encoding scheme within the same cell to consider cosite channel interference (CSI) when chromosomes are generated. The cell base crossover is also used. This proposed method improves solution quality within limited time.

• 한국인터넷방송통신학회논문지
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• 제18권3호
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• pp.201-207
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• 2018

2차원 할당 문제는 다항시간 알고리즘이 알려지지 않은 NP-완전 문제이다. 본 논문은 위치간 거리가 일정하지 않은 랜덤형 2차원 할당 문제의 최적 해를 $O(n^2)$ 수행 복잡도로 찾을 수 있는 알고리즘을 제안하였다. 제안된 알고리즘은 단순히 거리 합을 오름차순으로, 물동량 합을 내림차순으로 정렬하여 1:1 매치시킨 최소 거리 위치에 최대 물동량 시설을 배정하는 전략을 수행하고, 위치별 거리와 시설별 물동량 상관관계를 최적으로 반영하기 위해 시설들을 교환하는 전략을 적용하였다. 실험 데이터에 적용한 결과, 제안 알고리즘은 $O(n^2)$의 다항시간 알고리즘임에도 불구하고 메타휴리스틱 방법의 일종인 유전자 알고리즘의 해를 개선할 수 있었다.

• Journal of Information Processing Systems
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• 제10권2호
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• pp.193-214
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• 2014

Load balancing is the major benefit of any distributed system. To facilitate this advantage, task duplication and migration methodologies are employed. As this paper deals with dependent tasks (DAG), we used duplication. Task duplication reduces the overall schedule length of DAG along-with load balancing. This paper proposes a new task duplication algorithm at the time of tasks assignment on various processors. With the intention of conducting proposed algorithm performance computation; simulation has been done on the Netbeans IDE. The mesh topology of a distributed system is simulated at this juncture. For task duplication, overall schedule length of DAG is the main parameter that decides the performance of a proposed duplication algorithm. After obtaining the results we compared our performance with arbitrary task assignment, CAWF and HEFT-TD algorithms. Additionally, we also compared the complexity of the proposed algorithm with the Duplication Based Bottom Up scheduling (DBUS) and Heterogeneous Earliest Finish Time with Task Duplication (HEFT-TD).