• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.153-156
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• 2002

In this paper, we have designed a small size lumped/distributed hybrid element directional coupler using parallel coupled-line theory. a hybrid lumped equivalent circuit for a conventional parallel directional coupler is proposed. The equivalent circuit and design formula for the presented lumped element coupler are derived based on the even- and odd-mode properties of a parallel-coupled line. By using the derived design formula, we have extracted design parameters and designed the 3㏈ and 10㏈ small size lumped element directional couplers at the center frequency of 2Ghz. Excellent agreements between design theory and simulation on the designed directional couplers show the validity of this paper.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.269-272
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• 2001

In this paper we proposed the format converter design and implementation for real time image processing. This design method is based on realized the large processor-per-pixel array by integrated circuit technology in which this two types of integrated structure is can be classify associative parallel processor and parallel process with DRAM cell. Layout pitch of one-bit-wide logic is identical memory cell pitch to array high density PEs in integrate structure. This format converter design has control path implementation efficiently, and can be utilized the high technology without complicated controller hardware. Sequence of array instruction are generated by host computer before process start, and instructions are saved on unit controller. Host computer is executed the pixel-parallel operation starting at saved instructions after processing start

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.322-328
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• 2011

This paper presents inverse kinematics and workspace analysis of a planar three degree-of-freedom (DOF) parallel manipulator. Furthermore, optimization problem of the manipulator is presented. The manipulator adopts PRR (Prismatic-Revolute-Revolute) mechanism and the prismatic actuators are fixed to the base. This leads to a reduction of the inertia of the moving links and hence enables it to move with high speed. The actuators are linear electric motors. First, the mechanism based on the geometry of the manipulator is introduced. Second, a workspace analysis is performed. Finally, design optimization is carried out to have large workspace. The proposed approach can be applied to the design optimization of various three DOF parallel manipulators in order to maximize their workspace. The performance of mechanism is improved and satisfies the requirements of workspace to align micro-components.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.361-362
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• 2011

• Korean Journal of Computational Design and Engineering
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• v.13 no.3
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• pp.217-226
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• 2008

Web Services for CAD (WSC) aims at interoperation with CAD systems based on Web Services. This paper introduces one part of WSC which enables remote users to retrieve assembly model data using Web Services. However, retrieving assembly model data takes long time. To resolve this problem, this paper proposes using parallel Web Services. As assembly models comprise a set of part models, it is easy to separate the problem domain into smaller problems. In addition, Web Services inherently supports distributed computing. This characteristic makes the parallel processing of Web Services easy. Firstly, the implementation of WSC which retrieves assembly model data based parallel Web Services is shown. And then, for the comparison, the experiments on the retrieval of assembly model data based on single Web Services and parallel Web Services are shown.

• Structural Engineering and Mechanics
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• v.5 no.5
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• pp.635-644
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• 1997

The paper reviews the implementation and evaluation of exact methods for the computation of transcendental structural eigenvalues, i.e., critical buckling loads and natural frequencies of undamped vibration, on multiple instruction, multiple data parallel computers with distributed memory. Coarse, medium and fine grain parallel methods are described with illustrative examples. The methods are compared and combined into hybrid methods whose performance can be predicted from that of the component methods individually. An indication is given of how performance indicators can be presented in a generic form rather than being specific to one particular parallel computer. Current extensions to permit parallel optimum design of structures are outlined.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2077-2089
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• 1996

In this paper, a memory organization and its control method are proposed for the implementation of parallel Virterbi decoders. The design is mainly focused on lowering the hardware complexity of a parallel Viterbi decoder which is to reduce the decoding speed. The memories requeired in a Viterbi decoder are the SMM(State Metric Memory) and the TBM(Traceback Memory);the SMM for storing the path metrics of states and the TBM for storing the survial path information. A general parallel Viterbi decoder for high datarate usually consists of multiple ACS (Add-Compare-Select) units and their corresponding memeory modules.for parallel ACS units, SMMs and TBMs are partitioned into smaller independent pairs of memory modules which are separately interleaved to provide the maximum processing speed. In this design SMMs are controlled with addrss generators which can simultaneously compute addresses of the new path metrics. A bit shuffle technique is employed to provide a parallel access to the TBMs to store the survivor path informations from multiple ACS modules.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.408-421
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• 2008

In this paper, the parallel operation for a FC generation system is introduced and designed in order to increase the capacity for the distributed generation of a proton exchange membrane fuel cell (PEMFC) system. The equipment is the type that is used by parallel operated PEMFC generation systems which have two PEMFC systems, two dc/dc boost converters with shared dc link, and a grid-connected dc/ac inverter for embedded generation. The system requirement for the purpose of parallel operated generation using PEMFC system is also described. Aspects related to the mechanical (MBOP) and electrical (EBOP) component, size, and system complexity of the distributed generation system, it is explained in order to design an optimal distributed generation system using PEMFC. The optimal controller design for the parallel operation of the converter is suggested and informative simulations and experimental results are provided.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1121-1130
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• 2004

The Genetic Algorithm (GA), an optimization technique based on the theory of natural selection, has proven to be a relatively robust means of searching for global optimum. It converges to the global optimum point without auxiliary information such as differentiation of function. In the case of a complex problem, the GA involves a large population number and requires a lot of computing time. To improve the process, this research used parallel processing with several personal computers. Parallel process technique is classified into two methods according to subpopulation's size and number. One is the fine-grained method (FGM), and the other is the coarse-grained method (CGM). This study selected the CGM as a parallel process technique because the load is equally divided among several computers. The given design domain should be reduced according to the degree of feasibility, because mechanical system problems have constraints. The reduced domain is used as an initial design domain. It is consistent with the feasible domain and the infeasible domain around feasible domain boundary. This parallel process used the Message Passing Interface library.

• Journal of applied mathematics & informatics
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• v.5 no.2
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• pp.277-284
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• 1998

The reliability and an estimate for it are derived for series-parallel and parallel-deries stress-strength model under assumption that all components are subjected to a common stress. We also obtain the asymptotic normal distribution of the estimate.