• Informatization Policy
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• v.22 no.4
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• pp.91-104
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• 2015

This study tests the effects of differential association, definitions, differential reinforcement and imitation from social learning theory in the explanation of university students' crimes in social network services. In addition, this study tests the interaction effects between social learning factors and other factors such as low self-control, subcultural environment, and crime opportunity for the integrated approach. Using data from 486 university students in Seoul, results show that both definition and imitation have significant influences on crimes, even though differential association and differential reinforcement factors have no significant influences on crimes in social network services. Results also reveal that there are significant interaction effects between definition and subcultural environment, which meana that definition has a strong effect on crimes in high subcultural environment. In addition, it is found that reinforcement has also a strong effect on crimes in high crime opportunity and that interaction effect between imitation and low self-control is significant, which means that imitation has a strong effect on crimes in low self-control students.

• Journal of the Korean Regional Science Association
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• v.6 no.2
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• pp.123-147
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• 1990

This paper examines the changing geography of producer service industries in the 1980s. The foci of this study are to analyze the regional distribution of each producer services, and to reveal the spatial linkage of producer services. Further this paper asserts the potential role of producer services for reducing the potential endogenous development in the periphery. During the 1981-86 period, producer service industries grew more rapidly than other service sectors and manufacturing sector. The main reason of the raid growth of producer services is attributable to an increase in demand for intermediate services from manufacturing firms. In order to compete an increasingly complex business environment, firms have expanded the amount of effort devoted to activities such as planning, coordination and control, and consequently have increased their use of producer services. The most distinctive feature of the location of producer services is spatial concentration into Seoul and surrounding region. Especially the degree of the concentration o business services into the Capital Region has been accelerating during the 1990s. The pattern of employment growth and regional distribution of producer services show a clear core / periphery disparity. Much of the regional inequality in producer services is largely due to variation in demand associated with the pattern of corporation headquarters with the pattern of corporation headquarters and branch plants location with large manufacturing firms. The analysis of spatial division of labor reflects that producer services are related to the location of headquarters in manufacturing industry. Headquarters in manufacturing firms and business service firms tend to cluster each other. Most of the headquarters spatially separated from branch offices are clustered heavily in Seoul. Especially headquarters of business services and insurance services are overwhelmingly concentrated into Seoul. The firms whose headquarters are located in Seoul have a linkage pattern on a nationwide scale. It is viewed have little potential for generating local multiplier effects and regional development. In the light of the result of this study, producer services are not likely to disperse soon to peripheral regions. Consequently the absence of policies directed at enhancing producer sevice in the periphery, concentration tendency would continue to reinforce the core's dominance at the expense of peripheral regions. From a regional perspective, the quality of a region's producer service sector is a key determinant of economic growth, since manu industrial location decisions are influenced by the differential availability of producer services among regions. Poor performance of producer services in peripheral regions seemed to be linked to the region's manufacturing base. Low-wage, standardized branch plants are not likely to induce the growth in knowledge intensive services associated with high-technology corporate headquarters. Producer services may help to create and attract new business including manufacturing firms, and also to enhance the productivity and competitiveness of local firms. Therefore the provision of service producing activities would be lead not only to generate and retain endogenous development but also to attract external firms, especially small and medium sized firms which have a lower propensity of internalized services. Hence, it may be more efficient to create and expanse new locally owned producer services rather than to attract branch plants of mult-locational firms in order to make indigenous economic development.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1855-1858
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• 2002

A number of MPLS ATM systems have been proposed to increase the access speed of current routers, which only support the best-effort service. However, the MPLS ATM systems have to support the so-called differential service, which discriminates the applications according to the service class because they do not be satisfied the Internet users who use diverse applications. In this paper, to support this differential service a detailed forwarding procedure based on a LSP control method and an application-based marking algorithm is suggested. The LSP control method establishes several different LSPs for each FEC according to the service class and the application-based marking algorithm chooses a proper differential service depending on the application category. Also, a design scheme of forwarding engine, which can be easily implemented with a minimum modification of existing MPLS ATM systems is proposed. And, the best simulation result of high priority application category is gained when the proposed forwarding algorithm is comparedwithexistingalgorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1869-1876
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• 2006

Recently, STC techniques have been considered to be candidate to support multimedia services in the next generation mobile radio communications and have been developed the many communications systems in order to achieve the high data rates. In this paper, we Nose the Trellis-Coded Differential Space Time Modulation system with multiple symbol detection. The Trellis-code performs the set partition with unitary group codes. The Viterbi decoder containing new branch metrics is introduced in order to improve the bit error rate (BER) in the differential detection of the unitary differential space time modulation. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbi decoder improves BER performance without sacrificing bandwidth and power efficiency.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.223-229
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• 2004

Recently, OFDM and STC techniques have been considered to be candidate to support multimedia services in the next generation mobile radio communications and have been developed the many communications systems in order to achieve the high data rates. In this paper, we propose the Trellis-Coded Differential Space Time Modulation-OFDM system with multiple symbol detection. The Trellis-code performs the set partition with unitary group codes. The Viterbi decoder containing new branch metrics is introduced in order to improve the bit error rate (BER) in the differential detection of the unitary differential space time modulation. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbl decoder improves BER performance without sacrificing bandwidth and power efficiency.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.219-228
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• 2020

The purpose of this research is to examines the effect of the audit offer and simultaneous tax services from auditors on the firm value of clients. To test this hypothesis, we used the samples of the auditors' tax services selected from firms listed on the securities markets of Korea. We use the methodology of regression analysis. The major findings are as follows. First, TAX_SER has a positive relationship with the firm value. The knowledge and experience resulting from the offer of audit services are applied to the process of offering tax services to enhance the professionalism of audit and tax services. Second, the analysis was performed to determine if the type of tax services from auditors and the type of listed markets make any difference in the effect of TAX_SER1 on TQ; the study has revealed that only tax adjustment has a positive effect on TQ in the type of tax services. Depending on the type of listed markets, TAX_SER1 has been found to have a differential effect on the firm value. The results show that investors might decide to invest in those firms where the auditor could increase the firm value through audit and tax services.

• Proceedings of the Technology Innovation Conference
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• 2006.02a
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• pp.248-263
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• 2006

The convergence in telecommunication and broadcasting is one of the most popular topics in these days. For example, the characteristic of IPTV -internet protocol television-is controversial in the extreme. In Korea the IPTV operators are mainly the telecommunication service operators. So it is natural that the IPTV services are categorized to the telecommunication services. But the Broadcasting service providers, especially the CATV providers who can serve the TPS-triple play service- like IPTV players insist that the IPTV should be regulated as a broadcasting service. This paper will analyze whether the regulation in which the IPTV is categorized to one of the broadcasting services is better than the case of telecommunication services. To examine this, the social welfare analysis is conduced and the differential oligopoly market model is used. Together with that, this paper suggests that we can improve the social welfare by the asymmetric regulation between IPTV and D-CA TV. This means that in Korea the IPTV has a weak substitution relation with the D-CA TV and the IPTV should be dealed as a new convergence service that differs from traditional broadcasting services.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.824-830
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• 2010

In order to prepare for increasing performance requirement for Differential Global Navigation Satellite System (DGNSS) services of International Maritime Organization (IMO) and International Association of Lighthouse Authorities (IALA), this paper focuses on design of network-based Automatic Identification System (AIS) reference station system that can perform the functionality of Differential Global Positioning System (DGPS) reference station in an AIS base station system. AIS base station receives the differential corrections from the DGPS reference station, and it is not a method for transmitting the received differential corrections to onboard AIS units, but it is a method for generating the optimized differential corrections for onboard AIS units in AIS coverage. Therefore this paper proposes an algorithm for generating the differential corrections at AIS reference station, and performs the performance assessment of the proposed algorithm based on DGPS correction data measured from a DGPS reference station. Finally this paper discusses the test results and efficiency of the proposed system.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.463-467
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• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. The field experiments on pressure differential systems for smoke management in two high buildings of 20 stories and 21 stories are carried out to evaluate the features of airflow through open door between accommodation and lobby. The procedures and results of experiments are presented.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.458-462
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• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. The core technology for development of smoke management system is analysis tool of fan used in pressure differential system. The experiments on performance of sirroco-typed fan are carried out to evaluate the features of fan and present the experimental data for numerical analysis.