• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.668-679
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• 2004

When users of mobile environments move fast or slow into a number of base stations(BS) and request the services of continuous media data such as video or audio, this study examines what the caching has the usefulness in mobile environments. Namely, to reduce packet disconnections and network overheads in mobile environments and minimize transmission delay time, we propose domain-based hierarchical caching structure and study whether application of caching has the usefulness. So we have a model based on user environments and hierarchical network structure to process continuous media services, and analyze the usefulness of caching which depends on the mobile patterns of user and the locations of caching nodes. And then, we research whether caching offers the usefulness in mobile environments. As the result, we are able to see that an adaptable application of caching is needed because the hit ratio and the number of replacement vary in large according to mobile patterns of user and locations of caching.

• Electronics and Telecommunications Trends
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• v.21 no.2 s.98
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• pp.88-97
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• 2006

융합과 복합이라는 컨버전스가 이슈가 되고 있는 가운데, 통신사업자들은 새로운 형태의 컨버전스 서비스를 통해 신규 수익원을 확보하고 이용자 편의를 증대시키고자 많은노력과 투자를 하고 있다. 하지만 학계, 산업계 일부에서는 이러한 컨버전스 서비스가 융합, 결합할 때 나타나는 기술적 결함과 기존 서비스 및 신규 서비스 간 대체, 보완 경쟁 등으로 그 수요가 틈새 시장 수준에 그칠 것이라는 우려를 나타내기도 한다. 컨버전스는 이미 통신시장의 새로운 패러다임으로 자리를 잡았으며, 정부도 IT839의 지속적인 추진과 발전을 위해 컨버전스 형태 서비스에 많은 관심을 보이고 있다. 이에 본 고에서는 주요 컨버전스 서비스의 최근 동향을 살펴보고, 소비자 설문 조사를 통해 신규 컨버전스 서비스에 느끼는 효용과 중요도 분석을 하고 이를 바탕으로 사업자는 물론 고객들에게 보다 경쟁력 있는 컨버전스 서비스가 자리매김하기 위한 전략적 시사점을 제시하고자 한다.

• The Journal of Korean Institute of Information Technology
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• v.17 no.7
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• pp.123-131
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• 2019

In this paper, related studies were investigated by dividing them into cost-benefit analysis, security continuity services, and SW-centric calculations. The case analysis was conducted on A institutions in the United States, Japan and South Korea. Based on this, an improvement model was prepared through comparison with the current system. The SCS(Security Continuity Service) performance evaluation system-based information protection service cost calculation model is proposed. This method applies a service level agreement(SLA) and NIST Cybersecurity framework that are highly effective through cost-effectiveness analysis and calculates consideration based on characteristics, performance criteria, and weights by information protection service. This model can be used as a tool to objectively calculate the cost of information protection services at public institutions. It is also expected that this system can be established by strengthening the current recommended statutory level to the enforceability level, improving the evaluation system of state agencies and public institutions, introducing a verification system of information protection services by national certification bodies, and expanding its scope to all systems.

• Journal of Korean Society of societal Security
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• v.4 no.1
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• pp.57-65
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• 2011

Studying the operation of urban control plan and control program of urban plan facilities to present development direction of urban plan in the future by performing multi-variate analysis, the research acquired the following conclusion. It is required to institutionally activate the inhabitants' participation by reflecting spontaneous participation and opinion of inhabitants to adminstration so that the effect of business can be maximized in the stage of establishing urban control plan. Furthermore, the participation of role dividing type is necessary to adjust and connect the interest of expert that has experience in practical business of overall urban plan, inhabitant and self-governing body. It is required to reduce the service supplied by government so as to enhance policy of plan-first and development last for facilities with high importance and utility such as road, park and water supply/sewage, etc as well as to seek control program that expands the participation of private sector for administration for which private service is possible.

• Journal of the Korean Society for information Management
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• v.36 no.1
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• pp.269-294
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• 2019

To effectively cope with new and different types of disasters, it is very important to communicate and update disaster information to the public quickly and efficiently. SNS enables rapid spread of information and continuous exposure. SNS enables two-way communication by directly communicating with users. SNS complements the shortcomings of mass media, and increases the effectiveness of disaster management work. This study analyzed user awareness and requirements to derive effective methods of SNS operation of disaster management institutions. For this purpose, a user survey was conducted to identify the types of information that are highly user-interested and to select information items suitable for SNS services. Through this, we suggest ways to improve the SNS disaster record information service of the disaster management institution.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.151-160
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• 2005

In case of public transit such as bus system, the probability concept is used to evaluate the Level-of-Service of the operations. And each levels could be classified according to the linear probability value. (TCQSM: Transit Capacity and Quality of Service Manual-2nd Edition, TRB, Washington DC., 2003) In this case, the drivers or passengers wouldn't think that the service level isn't equivalent to the linear probability value. Thus the linear probability value doesn't exactly reflect the service level. This study shows the problems of using the linear probability value in classifying the service level through the case of evaluation of bus operation's punctuality, presented in TCQSM. To make up for the problems of such case, two methodologies are presented in this study. The method of determining Level-of-Service criteria using probability density of headway variation's distribution, presented in this paper, adequately reflects passenger's expected waiting time. According to the application result to real bus operation data, it tis better than the method of TCQSM to evaluate the reliability of bus operations. However further research about the relations between utility difference and passenger feeling of service level in necessary to apply the method that uses the utility function. It remains as the limitation of this paper.

• Journal of Korea Port Economic Association
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• v.28 no.3
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• pp.91-110
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• 2012

In the modern management literature, knowledge has been recognized as a new strategic resource enabling a firm to create its competitiveness. Shipping companies under fierce competitive structure need to pay attentions to the utility of knowledge management. A shipping firm may develop its unique service capability by classifying, sharing, and transferring the data, information and knowledge obtained from both inside and outside its global service network. The current study attempts to analyze influential relationships between liner shipping firms' knowledge management and service capabilities. In order to achieve this goal, this study designed a knowledge chain model measuring shipping companies' knowledge management levels and tested its validity and reliability based on a total of 80 replied questionnaires from national and foreign liners. The empirical result presents that supportive and primary activities composing a knowledge chain could exert significant positive influences on the enforcement of shipping service capabilities. This research shows that the utility of knowledge management is adoptable in the maritime industry, and recommends that shipping firms should recognize strategic importance of knowledge and actively pursue knowledge management at an entire firm level.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.1-11
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• 2012

The purpose of this paper is to estimate 'willingness to pay' for mobile data service by using contingent valuation method with double bounded dichotomous choice question. The findings are as follows.: First, the willingness to pay of mobile data service is considerably lower than current retail price. Second, the perceived degree of mobile data service such as awareness and benefit recognition is positively related to the willingness to pay of mobile data service. Our results suggest that active promotion and strengthening of the content of mobile data service are needed in order to enhance the profitability of mobile operators. The analysis results will be used to set the mobile operator's pricing strategy and to build up a successful communication policies in the mobile ecosystem.

• 한국IT서비스학회:학술대회논문집
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• 2003.11a
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• pp.339-347
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• 2003

최근 들어 CMM, SPICE 등 국제적 소프트웨어 프로세스 심사 및 개선 모형이 국내 SI업계 및 SW개발 기업들에 널리 활용되고 있다. 이러한 평가모형은 초기에 프로세스의 능력평가를 위해 이용되었으나 프로세스 개선을 통한 기업의 경쟁력 강화에 대한 효용성이 입증되면서 점진적으로 프로세스 개선활동의 핵심적 방법으로 활용되고 있다. 본 연구에서는 이러한 소프트웨어 프로세스 향상이 조직성과에 미치는 효과에 대해 실증적 자료를 토대로 분석한다.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.66-71
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• 2011

This paper evaluates the performance and effectiveness of a layered coding scheme for an integrated mobile satellite systems, where the main target services are multimedia broadcasting and multicasting services (MBMS). In this integrated system, the satellite and complementary ground components (CGC) cooperate to provide high quality services. A layered coding scheme is a receiver driven adaptive schemes which adapts to the channel condition at the receiver. In this paper, we introduce a layered turbo coding scheme, and evaluates the performance in various scenarios, and discuss its effectiveness. The demonstrated results in the paper can be utilized in order to design an efficient integrated mobile satellite system, in the future.