• IE interfaces
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• v.17 no.spc
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• pp.69-78
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• 2004

This paper presents a simulated algorithm(SA) for the optimal reliability design problem of a series system with multiple component choices incorporated at each subsystem. The objective of the problem is to maximize the system reliability while satisfying some constraint on system budget. The problem is formulated as a nonlinear binary integer programming problem and characterized as an NP-hard problem. The SA algorithm is developed by introducing some solution-improvements methods. Numerical examples are tested and the results are compared. The results have demonstrated the efficiency and the effectiveness of the proposed SA algorithm.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.2
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• pp.78-86
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• 2010

The traveling purchaser problem(TPP) is a generalization of the well-known traveling salesman problem(TSP), which has many real-world applications such as purchasing the required raw materials for the manufacturing factories and the scheduling of a set of jobs over some machines, and many others. TPP also could be extended to the vehicle routing problem(VRP) by incorporating additional constraints such as multi-purchaser, capacity, distance and time restrictions. In the last decade, TPP has received some attention of the researchers in the operational research area. However it has not received the equivalent interest as much as TSP and VRP. Therefore, there does not exist a review of the TPP. The purpose of this paper is to review the TPP and to describe solution procedures proposed for this problem. We also introduce the ILP formulation for the multiple TPP(mTPP) which is generalized type of TPP. We compare the system performance according to change from TPP to mTPP.

• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.106-118
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• 2007

This paper present a new optimization model to generate aggregate production planning by considering electric cost. The new Time Of Switching (TOS) electric type is introduced by switching over Time Of Day (TOD) and Time Of Use (TOU) electric types to minimize the electric cost. The fuzzy demand and Dynamic inventory tracking with multiple plant capacity are modeled to cover the uncertain demand of customer. The constraint for minimum hour limitation of plant running per one start up event is introduced to minimize plants idle time. Furthermore; the Optimal Weight Moving Average Factor for customer demand forecasting is introduced by monthly factors to reduce forecasting error. Application is illustrated for multiple cement mill plants. The mathematical model was formulated in spreadsheet format. Then the spreadsheet-solver technique was used as a tool to solve the model. A simulation running on part of the system in a test for six months shows the optimal solution could save 60% of the actual cost.

• Management Science and Financial Engineering
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• v.6 no.2
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• pp.47-67
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• 2000

It is discussed how to assign delivery tasks to automated guided vehicles (AGVs) for multiple container cranes in automated container terminals. The primary goal of dispatching AGVs is to complete all the lading and discharging operations as early as possible, and the secondary goal is to minimize the total travel distance of AGVs. It is assumed that AGVs are not dedicated to a specific container crane but shared among multiple cranes. A mathematical formulation is developed and a heuristic algorithm is suggested to obtain a near optimal solution with a reasonable amount of computational time. The single-cycle and the dual-cycle operations in both the seaside and the landside operations are analyzed. The effects of pooling AGVs for multiple container cranes on the performance of an entire AGV system are also analyze through a numerical experiment.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1549-1558
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• 2011

In this paper, we address the problem of bandwidth sharing among multiple primary users and multiple secondary users in a cognitive radio network. In cognitive radio networks, effective spectrum assignment for primary and secondary users is a challenge due to the available broad range of radio frequency spectrum as well as the requisition of harmonious coexistence of both users. To handle this problem, firstly, Bertrand game model is used to analyze a spectrum pricing in which multiple primary users emulate with each other to acquire maximal profit. After that, we employ Cournot game to model the spectrum sharing of secondary users to obtain optimal profit for each user also. Simulation results show that our scheme obtains optimal solution at Nash equilibrium.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.1
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• pp.85-92
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• 2008

An architecture for multiple radar tracking systems can be broadly categorized according to the methods in which the tracking functions are performed : central-level tracking and distributed tracking. In the central-level tracking, target tracking is performed using observations from all radar systems. This architecture provides optimal solution to target tracking. In distributed tracking, tracking is performed at each radar system and the composite track information is formed through track fusion integrating multiple radar-level tracks. Track-to-track fusion and track-to-track association are required to perform in this architecture. In this paper, issues and recent research on the two tracking architectures are surveyed.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.10
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• pp.930-939
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• 2004

In this paper, both dynamic constraints and kinematic constraints are considered for the analysis of manipulability of robotic systems comprised of multiple cooperating arms. Given bounds on the torques of each Joint actuator for every robot, the purpose of this study is to drive the bounds of task-space acceleration of object carried by the system. Bounds on each joint torque, described as a polytope, is transformed to the task-space acceleration through matrices related with robot dynamics, robot kinematics, object dynamics, grasp conditions, and contact conditions. A series of mathematical manipulations including the procedure calculating minimum infinite-norm solution of linear equation is applied to get the reachable acceleration bounds from given actuator dynamic constrains. Several examples including two robot systems as well as three robot system are shown with the assumptions of complete-constraint contact model(or' very soft contact') and insufficient or proper degree of freedom robot.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.1
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• pp.63-72
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• 2008

This study considers the motion response of multiple adjacent floating bodies in waves. As a method of solution, a three-dimensional Rankine panel method is adopted in time domain. For the validation of the developed numerical method, the motions of two adjacent Series 60 hulls and ship-barge model are estimated. The computational results are compared with other numerical and experimental analyses, showing favorable agreement.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.921-922
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• 2006

This paper presents a novel scheme that quickly searches for the sweet spot of multiple array antennas, and locks on to it for high-speed millimeter wavelength transmissions. The proposed method utilizes a modified genetic algorithm, which selects a superior initial group through preprocessing in order to solve the local solution in a genetic algorithm. TDD (Time Division Duplex) is utilized as the transfer method and data controller for the antenna. Once the initial communication is completed for the specific number of individuals, no longer antenna's data will be transmitted until each station processes GA in order to produce the next generation. After reproduction, individuals of the next generation become the data, and communication between each station is made again. Simulation results confirmed the efficiency of the proposed method.

• Structural Engineering and Mechanics
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• v.41 no.5
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• pp.591-604
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• 2012

This paper provides an iteration approach for the solution of multiple notch problem, which is based on the complex variable boundary integral equation (CVBIE). The contours of notches are applied by some loadings. The source points are assumed on the boundary of individual notch and the displacements along the boundaries become unknowns to be investigated. After discretization of the BIE, many influence matrices are obtained. One does not need to assemble many influence matrices into a larger matrix. This will considerably reduce the work in the program. The displacements along the many boundaries can be obtained from an iteration. There is no limitation for the configuration of notches. Several numerical examples are provided to prove the efficiency of the suggested approach.