• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.83-88
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• 2017

This paper describes the azimuth accuracy test of phase comparison direction finding method using F-16 fighter scale-down model. When the antennas are placed on the bottom of a fighter, reflection signals caused by an aircraft structure arises and an azimuth error occurs. In this research, the F-16 fighter scale-down model was made to 5:1, and five antennas were placed on the bottom of the model, then the radio waves of emitters were received by the antennas in the $0-360^{\circ}$ azimuth angles. The accuracy test was performed by numerically analyzing the phases of the radio waves received by the five antennas. The azimuth error of the phase comparison direction finding with scale-down model was measured to be less than $0.5^{\circ}$ when the signal noise ratio was larger then 0dB, and it could be very useful for the design of the phase comparison direction finding method of the fighter.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.425-430
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• 2016

This study is to improve the design of bus transfer information that can be substantially used. This study has been processed using the following steps. First, I tried to define the information design and way-finding information design. Secondly, I have researched several case studies, and considered solutions. Finally, I evaluated way-finding maps through pair-wise comparisons, and drew needs through an interview. As the result of this research, there were some problems in font size, improper space between letters and non-consistent information. To solve these problems, the information has to be clear using easy symbols to be well-recognized by citizens. Also, the font size needs to be decided by a calculation of minimum legible size of letters. Lastly, a value contrast between a background color and a letter color needs to be applied more than 70 percent for better visibility. The study is expected to be used as a reference which helps informational design to be developed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.9
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• pp.609-616
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• 2022

The performance of antenna reflectors crucially depends on the faceting error of the surface. The force density method (FDM) has been widely used for the form-finding analysis of the cable nets of reflectors. However, after performing form-finding of some cable nets, the effective reflective area will decrease. In addition, nonlinear deformations of the cable can not be achieved by using the FDM. Thus, an effective form-find methodology is proposed in this research. The whole parts of the cable networks are described by the absolute nodal coordinate formulation. The form-finding analysis of the reflector with standard configuration is performed to validate the proposed methodology. The influence of boundary condition changes on the configuration accuracy of the cable net is investigated.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.2
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• pp.1-11
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• 2005

The network structures of a hyperlinked environment can be a rich source of information about the contents of the environment and it provides effective means for understanding it. Recently, there have been a number of algorithms proposed analyzing hypertext link structure so as to determine the best authorities for a given topic or query. In this paper, we review the algorithm of mutual reinforcement relationship for finding hubs and authorities from World Wide Web, and suggest SHA, a new approach for link-structure analysis, which uses the relationships among a set of relative authoritative pages, a set of hub pages, and a set of super hub pages.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.2
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• pp.47-58
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• 2001

The purpose of this study is to present methods for determining the k most vital arcs (k-MVAs) in shortest path problem (SPP) using evolutionary algorithms. The problem of finding the k-MVAs in SPP is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the shortest distance between two specified nodes. Generally, the problem of determining the k-MVAs in SPP has been known as NP-hard. Therefore, to deal with problems of the real world, heuristic algorithms are needed. In this study we present three kinds of evolutionary algorithms for finding the k-MVAs in SPP, and then to evaluate the performance of proposed algorithms.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2665-2667
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• 2004

This paper presents a study of a position finding system for a reactor inspection robot. The position of PSD(Position Sensitive Detector) sensor is calculated by the degree of pan-tilt and the difference in height between pan-tilt and PSD. For that, the DSP which control pan-tilt is used for precise operation and the PIC microcontroller process PSD sensor data that indicate light incident position. A user using computer can acquire the conditions of pan-tilt and PSD.

• ETRI Journal
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• v.20 no.4
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• pp.327-345
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• 1998

This paper deals with the problem of one-to-one mapping of 2$^n$ task modules of a parallel program to an n-dimensional hypercube multicomputer so as to minimize the total communication cost during the execution of the task. The problem of finding an optimal mapping has been proven to be NP-complete. First we show that the mapping problem in a hypercube multicomputer can be transformed into the problem of finding a set of maximum cutsets on a given task graph using a graph modification technique. Then we propose a repeated mapping scheme, using an existing graph bipartitioning algorithm, for the effective mapping of task modules onto the processors of a hypercube multicomputer. The repeated mapping scheme is shown to be highly effective on a number of test task graphs; it increasingly outperforms the greedy and recursive mapping algorithms as the number of processors increases. Our repeated mapping scheme is shown to be very effective for regular graphs, such as hypercube-isomorphic or 'almost' isomorphic graphs and meshes; it finds optimal mappings on almost all the regular task graphs considered.

• Journal of Electrochemical Science and Technology
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• v.7 no.2
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• pp.115-131
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• 2016

Though battery chemistry and technology had been developed for over a hundred years back, increase in demand for storage energy, in the computer accessories, cell phones, automobile industries for future battery car and uninterrupted power supply, has made, the development of existing and new battery, as an emerging areas of research. With innovation of high energetic inexpensive Nano structure materials, a more energy efficient battery with lower cost can be competitive with the present primary and rechargeable batteries. Materials electrochemistry of electrode materials, their synthesis and testing have been explained in the present paper to find new high efficient battery materials. The paper discusses fundamental of electrochemistry in finding true cell potential, overvoltages, current, specific energy of various combinations of anode-cathode system. It also describes of finding the performance of new electrode materials by various experiments viz. i. Cyclic Voltammetry ii. Chronoamperometry iii. Potentiodynamic Polarization iv. Electrochemical Impedance Spectroscopy (EIS). Research works of different battery materials scientists are discussed for the development of existing battery materials and new nano materials for high energetic electrodes. Problems and prospects of a few promising future batteries are explained.

• Management Science and Financial Engineering
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• v.19 no.2
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• pp.1-11
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• 2013

An interesting puzzle in business practices is that although many researchers emphasize the benefits of a revenue-sharing contract, a wholesale contract has remained to be the most common contractual form. By introducing the concept of unobservable efforts, we examine the contractual efficiency of a wholesale contract and a revenue-sharing contract. The multi-task agency model and experimental design approach are used to analyze the relationship between the contractual efficiency and parameters. A major finding of our study is that a wholesale contract coordinates unobservable efforts, while it fails to coordinate the order quantity decision. Because unobservable efforts have mixed effects on the contractual efficiency, the superiority of contract type depends on parameters. This finding implies that a wholesale contract can be a competitive contract, especially when unobservable efforts are heavily involved. Our conclusion is that the current popularity of a wholesale contract is manager's rational response to complex supply chain environments rather than irrational behaviors.

• Journal of the military operations research society of Korea
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• v.26 no.2
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• pp.120-130
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• 2000

The purpose of this study is to present a method for determining the k most vital arcs in shortest path problem using an evolutionary algorithm. The problem of finding the k most vital arcs in shortest path problem is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the total length of shortest path. Generally, the problem determining the k most vital arcs in shortest path problem has known as NP-hard. Therefore, in order to deal with the problem of real world the heuristic algorithm is needed. In this study we propose to the method of finding the k most vital arcs in shortest path problem using an evolutionary algorithm which known as the most efficient algorithm among heuristics. The method presented in this study is developed using the library of the evolutionary algorithm framework and then the performance of algorithm is analyzed through the computer experiment.