• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.70-79
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• 2012

The Korean Government recently has been focused on strengthening competitiveness of order and stimulating construction market in the international construction industry. It has planned to extend the ODPs (overseas development projects) in order to diversifying the international construction market of which is domestic construction companies, placing too much emphasis on plant projects of the Middle East. However, literature review of risk analysis in the ODPs shows that the number of case study is several. Therefore, Authors asserted the necessity of risk analysis in the ODPs. The purpose of this study is to suggest a methodology that find KRFs (key risk factors) in the ODPs and analyze them, using AHP and Fuzzy theory. As a result, the 37 KRFs are selected and explained characteristics of them. A future direction of this study is to suggest a risk management model in the ODPs and prove feasibility of it.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12B
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• pp.758-766
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• 2007

IStreaming services with a client-server architecture have scalability problem because a server cannot accomodate clients more than its processing capability. This paper introduces a case study for implementing H.264 streaming system based on P2P architecture in order to provide scalable and stable broadcast streaming services over the internet. The prototype system called OmniCast264 consists of the H.264 encoding server, the streaming server, the proxy server, and peer nodes. The proxy server dynamically manages placement of the peer nodes on the P2P network. Omnicast264 has the concepts of distributed streaming loads, real-time playback, error-robustness and modularity. Thus, it can provide large-scale broadcast streaming services. Finally, we have built P2P streaming systems with 12 PCs connected serially or in parallel. The experiment shows that OmniCast264 can provide real-time playback.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.581-592
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• 2015

In the GORRAM, the estimation of resource requirements for wartime equipment is based on the ELCON of the USA. The number of vulnerability groups of ELCON are 22, but unfortunately it is hard to determine how the 22 groups are classified. Thus, in this research we collected 505 types of basic items used in wartime and classified those items into new vulnerability groups using AHP and cluster analysis methods. We selected 11 variables through AHP to classify those items with cluster analysis. Next, we decided the number of vulnerability groups through hierarchical clustering and then we classified 505 types of basic items into the new vulnerability groups through K-means clustering.This paper presents new vulnerability groups of 505 types of basic items fitted to Korean weapon systems. Furthermore, our approach can be applied to a new weapon system which needs to be classified into a vulnerability group. We believe that our approach will provide practitioners in the military with a reliable and rational method for classifying wartime equipment and thus consequentially predict the exact estimation of resource requirements in wartime.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.711-723
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• 2017

This paper proposes a flight control system for an organic flight array(OFA) which has a new configuration to consist of multi modularized ducted-fan unmanned aerial vehicles (UAVs). The OFA is able to apply to various missions such as indoor reconnaissance, communication relay, and radar jamming by using capability of hover flight. The OFA has a distinguished advantage due to reconfigurable structure to assemble or separate with respect to its missions or operational conditions. A dynamic modelling of the OFA is derived based on equations of motion of the single ducted-fan modules. In order to apply nonlinear control method, an affine system of attitude dynamics is derived. Moreover, the control system is composed of a back-stepping controller for attitude control and a PID controller for position control. Then the performance of the proposed controller is verified via a numerical simulation under wind disturbance.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.472-485
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• 2014

This study focuses on the news making system of the prime time news of PSB in Korean society, where the presence of ethnic minorities is increasing rapidly. Although the World Wide Web has become one of the most attractive media over the last decade, Korean PSB, Korean Broadcasting System (KBS), still remains the most popular and influential medium. Therefore, the process of analyzing news making system of ethnic minorities in Korean society represented in Korean PSB as a social construction is meaningful in that it provides an important key to understand the cultural and political background and characteristics of society. For this purpose, the article tries to understand news making process when producing news related to ethnic minorities in the Korean society such as migrant workers, married migrant women and mixed-heritage children of multicultural families by interview with ten reporters in KBS. As a result, most KBS reporters had stereotypes towards multiculturalism and migrants and news reports relating to ethnic minorities are usually produced routinely, using a set of rules that have become part of KBS culture.

• Asia pacific journal of information systems
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• v.9 no.3
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• pp.159-175
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• 1999

For the past decade, although there have been many studies which examined factors influencing the extent of EDI systems implementation, it is very hard to find out studies which directly investigated what the effectiveness of EDI systems are, and which factors contribute to the successful implementation of EDI systems. In this regard, this research aims to explore for the factors which constitute the effectiveness of EDI systems as perceived, based on a survey from 202 companies. The major steps of the current research are as follows. First, in order to identify important factors constituting the effectiveness of EDI systems, previous research related to the effectiveness of EDI systems was reviewed and analyzed. Second, individual items which can be considered as candidates to represent the effectiveness of EDI systems were derived from this previous research review, and a survey questionnaire was developed using those derived items. Based on the developed survey questionnaire, a pretest was administered at several domestic business firms with experiences of EDI systems. Third, survey questionnaires were distributed to and collected from the 202 companies which experienced EDI implementation. Accordingly, this research derived out five factors constituting the effectiveness of EDI systems from the result of a multivariate data analysis: strategic advantage, time reduction in business process, accuracy improvement, cost reduction, and improvement of business process quality. It was also interesting to find that the factors of EDI effectiveness are divided into three levels, similarly to three levels of the Anthony's hierarchical model of organization(Anthony, 1965): strategic, managerial, and operational levels. Furthermore, from the levels of derived factors, we developed a conceptual model which explains the possible causal relations of those factors in a hierarchical manner.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.4
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• pp.15-22
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• 2004

This paper presents the channel analysis considering power distribution network(PDN) system of PCB. For achieve the target PDN system we proposed the useful design approach for acquiring the characteristic target of power distribution network in overall frequency ranges. The proposed method is based on the hierarchical approach related to frequency ranges and the path-based equivalent circuit model to consider the interference of the current paths between the decoupling capacitors and the board through it is a lumped model for fast and easy calculation, experimental results show that the proposed model is almost as precise as the numerical analysis. The analysis of PDN system shows that although the effective inductance of package dominatly affects the power noise and the signal transfer through data channel, the board PDNs also can not be neglected for achieving the accurate channel signaling. Therefore, we must design concurrently the chip, package, and board from the initial spec design of high speed digital system.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.38-45
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• 2016

For higher efficiency and reliability of railroad trains with many electronic sensors and actuators, a distributed control system with which electronic components communicate with each other in a distributed manner via a data network is considered. This paper considers Ethernet-based Train Communication Network (TCN) for this purpose and proposes a methodology to optimize the topology in terms of transmission latency and reliability, each of which is modeled as the number of traversing backbone nodes and the number of cables between vehicles, respectively. An objective function is derived accordingly and a closed-form optimum is obtained by relaxing the integer constraint of the number of vehicles for a unit network. Then, the final integer optimum is searched around it. Through numerical evaluation, the validity of the proposed methodology and the characteristics of the resulting solutions are shown.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.19-30
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• 2012

In recent decades, it has been known that the Discrete Event System Specification, or DEVS, formalism provides sound semantics to design a modular and hierarchical model of a discrete event system. In spite of this benefit, practitioners have difficulties in applying the semantics to real-world systems modeling because DEVS needs to specify a large size of sets of events and/or states in an unstructured form. To resolve the difficulties, this paper proposes an extension of the DEVS formalism, called the Structured DEVS formalism, with an associated graphical representation, called the DEVS diagram, by means of structural representation of such sets based on closure property of set theory. The proposed formalism is proved to be equivalent to the original DEVS formalism in their model specification, yet the new formalism specifies sets in a structured form with a concept of phases, variables and ports. A simplified example of the structured DEVS with the DEVS diagram shows the effectiveness of the proposed formalism which can be easily implemented in an objected-oriented simulation environment.

• Korean Journal of Social Welfare
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• v.65 no.3
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• pp.265-289
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• 2013

The purpose of this study is to analyse the reality and dynamics of transition of work-family reconciliation policy and gender regime in Germany to focus on recent introduction of parents benefit by applying meta path analysis. There is made of 'layering' in work-family reconciliation policy area. Because political barrier has alleviated they can introduce parents benefit, but cannot help stick to child care benefit because of internal barrier. But because parents benefit has activated by 'differential growth', German gender regime has suffered core transition of complementation that dominant structure has changed from 'sequential reconciliation' to 'concomitant reconciliation'. On the other hand, by 'purposeful decoupling' of gender area, core activists have attempted to cut the possibility of weakening of coordination relationship on main institutional areas of German model.