• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.663-663
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• 2002

The National Oceanographic Research Institute of KOREA started to survey for the basic data necessary to territorial sea and EEZ identification and marine development with Multi-Beam Echo Sounder(L3 SeaBeam 2112) since 1996. The Multi-Beam surveys has provided a very new and precise way of describing the morphology and nature of the underwater seabed. Multi-Beam Echo Sounder systems employ sound waves propagating at angles which vary from vertical to nearly horizontal. The locations on the bottom where echoes are generated cover a swath whose port to starboard width may be equal to many times the water depth. Newer Multi-beam bathymetric sonars provide both a beam by beam depth and backscatter amplitude of the bottom. But The backscattered amplitude didn't use for identification of bottom properties because backscatter amplitude effects by the many environmental variables of underwater and seabed. We investigates the utilization of geo-referenced backscatter amplitude and analysis of relationship between The Backscattered Amplitude and Sidescan Sonar imagery from Sea Beam 2112. For the backscattered amplitude imagery mainly represents the properties of sediment, we computed the beam geometry, time-varied amplifier gain, and mainly incidence angle to the topography using bathymetric model at each ping. In this paper, those issues are illustrated, and the angular independent imagery based on swath topographic model is described.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.4
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• pp.157-179
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• 2006

Recently, as business becomes more dependent on information technology for their operations, SI project managers are under increasing pressure to implement SI projects on time and within budget, and to satisfy customer requirements. For the success of SI projects and customer satisfaction, SI project managers should master the critical shills and knowledge requirements and consider the proper leadership style to lead the team members and to manage SI projects. The leadership style includes four categories, such as directive leadership, supportive leadership, participative leadership, and achievement-oriented leadership. This study has examined the project managers' competency and suggests the three competency factors, which are technical, human, and conceptual shills, for the success of SI projects and customer satisfaction. The study suggests that SI project managers should master the three critical skills and knowledge requirements, and consider the proper leadership style for the successful implementation of SI projects. Also SI project managers should consider contingency factors such as project size and duration and outcome variables such as protect performance and customer satisfaction so as to enhance the leadership effectiveness.

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.491-502
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• 2005

Reliable human performance is a prerequisite in securing the safety of complicated process systems such as nuclear power plants. However, the amount of available knowledge that can explain why operators deviate from an expected performance level is so small because of the infrequency of real accidents. Therefore, in this study, a database that contains a set of useful information extracted from simulated emergencies was developed in order to provide important clues for understanding the change of operators' performance under stressful conditions (i.e., real accidents). The database was developed under Microsoft Windows TM environment using Microsoft Access $97^{TM}$ and Microsoft Visual Basic $6.0^{TM}$. In the database, operators' performance data obtained from the analysis of over 100 audio-visual records for simulated emergencies were stored using twenty kinds of distinctive data fields. A total of ten kinds of operators' performance data are available from the developed database. Although it is still difficult to predict operators' performance under stressful conditions based on the results of simulated emergencies, simulation studies remain the most feasible way to scrutinize performance. Accordingly, it is expected that the performance data of this study will provide a concrete foundation for understanding the change of operators' performance in emergency situations.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.320-328
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• 2007

The sheath in underground power cables serves as a layer to prevent moisture ingress into the insulation layer and provide a path for earth return current. Nowadays, owing to the maturity of manufacturing technologies, there are normally no problems for the quality of the sheath itself. However, after the cable is laid in the cable tunnel and is operating as part of the transmission network, due to network construction and some unexpected factors, some problems may be caused to the sheath. One of them is the high sheath circulating current. In a power cable system, the uniform configuration of the cables between sections is sometimes difficult to achieve because of the geometrical limitation. This will cause the increase of sheath circulating current, which results in the increase of sheath loss and the decrease of permissible current. This paper will study the various characteristics and effects of sheath circulating current, and then will prove why the sheath current rises on the underground power cable system. A newly designed device known as the Power Cable Current Analyser, as well as ATP simulation and calculation equation are used for this analysis.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.305-323
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• 2015

Since various R&D projects about technology convergence was conducted by the government of Korea, the lack of liaisons among the projects has been accepted as serious issues related on the duplicated funding. In this article, we propose a research framework to analyze the relationship among national R&D projects about technology convergence. In detail, the projects have been sorted and categorized with the data collected from National Science and Technology Information Service (NTIS) in order to analyze the current state of national R&D projects. The linkages among projects are then established using the results of analysis on national R&D projects. Finally, the relationship maps have been developed. It is expected that the result could be applied to identify the relations among projects and handle problems on the duplicated funding.

• ETRI Journal
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• v.32 no.5
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• pp.740-749
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• 2010

In a machine translation system, word sense disambiguation has an essential role in the proper translation of words when the target word can be translated differently depending on the context. Previous research on sense identification has mostly focused on adjacent words as context information. Therefore, in the case of nominal compounds, sense tagging of unit nouns mainly depended on other nouns surrounding the target word. In this paper, we present a practical method for the sense tagging of Korean unit nouns in a nominal compound. To overcome the weakness of traditional methods regarding the data sparseness problem, the proposed method adopts complement-predicate relation knowledge that was constructed for machine translation systems. Our method is based on a sentential form recovery technique, which recognizes grammatical relationships between unit nouns. This technique makes use of the characteristics of Korean predicative nouns. To show that our method is effective on text in general domains, the experiments were performed on a test set randomly extracted from article titles in various newspaper sections.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4159-4164
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• 2012

This paper presents a chaotic circuit with voltage controllability for secure communication applications. The proposed circuit which has two control voltages consists of the nonlinear function block(NFB) with three MOS transistors, one source follower and non-overlapping two-phase clock generator for sample and hold. By SPICE simulation, chaotic dynamics such as time waveform, frequency analysis and bifurcations were analyzed. SPICE results showed that proposed circuit can make various chaotic signals by control voltage.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.187-200
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• 1998

This paper presents an original approach for solving short-term power scheduling in extended power system with two fuels in a unit and a limited fuel using Lagrangian relaxations. The underlying model incorporates the full set of costs and constraints including setup, production, ramping, and operational status, and takes the form of a mixed integer nonlinear control problem. Moreover, the mathematical model developed includes two fuels in a unit and a limited fuel, regulation reserve requirements of prespecified group of units. Lagrangian relaxation is used to disaggregate the model by generator into separate subproblems which are then solved with a nested dynamic program including empirical knowledges. The strength of the methodology lies partially in its ability to construct good feasible solutions from information provided by the dual. Thus, the need for branch-and-bound is eliminated. In addition, the inclusion of two fuels in a unit and a limited fuel provides new insight into the limitations of current techniques. Computational experience with the proposed algorithm indicates that Problems containing up to 23 units including 8 unit used two fuels and 24 time periods can be readily solved in reasonable times. Duality gaps of less than 4％ were achieved.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.27-47
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• 1999

Many enterprises are interested in using the IS development methodologies as a means of increasing system performance and solving the problems of delayed delivery time, excessive budget, and failure of integrated systems. Even if previous researches showed that the system productivity and quality improvement using the system development methodologies are very poor, we tried to find that the methodologies are meaningful as an innovative means for IS performance. We defined that the IS development methodology as a technical and managerial innovation for IS department. We intended to study the relationship between the implementation process of the IS development methodology divided into four steps and IS performance. A cross-sectional field survey with IS departments of domestic companies was conducted, and we used LISREL 8.12a to perform the structural equation model analysis and hypothesis verification. We found the meaningful relationship between the development methodology and qualitative performance. We reconfirmed that the relationship between the development methodology and quantitative performance is not meaningful as expected, which is the same result with the previous researches. But the qualitative performance affects very strongly to the quantitative performance. As a results, we suggest that IS managers and developers keep the principles of the IS development methodologies to get the quantitative performance through the qualitative performance improvement.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.11-33
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• 2013

We analyzed the structures and properties of the global financial market networks using social network analysis approach. The Minimum Spanning Tree (MST) lengths and networks of the global financial markets based on the correlation coefficients have been analyzed. Firstly, similar to the previous studies on the global stock indices using MST length, the diversification effects in the global multi-asset portfolio can disappear during the crisis as the correlations among the asset class and within the asset class increase due to the system risks. Second, through the network visualization, we found the clustering of the asset class in the global financial markets network, which confirms the possible diversification effect in the global multi-asset portfolio. Meanwhile, we found the changes in the structure of the network during the crisis. For the last one, in terms of the degree centrality, the stock indices were the most influential to other assets in the global financial markets network, while in terms of the betweenness centrality, Gold, Silver and AUD. In the practical perspective, we propose the methods such as MST length and network visualization to monitor the change of the correlation risk for the risk management of the multi-asset portfolio.