• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1441-1446
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• 2014

For the escape from a maze, the cooperative method by robot swarm was proposed in this paper. The robots can freely move by collecting essential data and making a decision in the use of sensors; however, a central control system is required to organize all robots for the escape from the maze. The robots explore new mazes and then send the information to the system for analyzing and mapping the escaping route. Three issues were considered as follows for the effective escape by multiple robots from the mazes in this paper. In the first, the mazes began to divide and secondly, dead-ends should be blocked. Finally, after the first arrivals at the destination, a shortcut should be provided for rapid escaping from the maze. The parallel-escape algorithms were applied to the different size of mazes, so that robot swarm can effectively get away the mazes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.87-94
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• 2010

It is widely known that cooperative spectrum sensing in which secondary users scattered in some region collaborate to detect primary users can significantly reduce the performance degradation due to the fading phenomenon. Most of previous works on cooperative spectrum sensing are based on the assumption that the local spectrum sensing decisions of secondary users are statistically independent. However, there can be practically some statistical correlation between the local decisions of any two secondary users in close proximity, which is caused by shadowing effect. In order to evaluate the effect of this correlation on the performance of collaborative spectrum sensing, we assumed that, for the case that a primary user are active in the spectrum of interest, any two local decisions are statistically correlated to each other with some level of constant correlation and independent otherwise, and analyzed the achievable throughput with the degree of correlation varying. The results showed that, as the degree of correlation gets higher, the throughput increases for the case of the AND fusion rule and decreases for the OR fusion rule.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7B
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• pp.517-527
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• 2012

This paper considers a cooperative communication system with a single relay node, where two-layer superposition coding and successive decoding is employed to reduce the expected distortion of a Gaussian source delivered. For the system, we propose a relay scheme which forwards an appropriate relay signal at the relay node, based on the local decoding result of layers and the decoding result of layers at the destination node fed back to the relay node. In the scheme, the relay signal is designed not only by applying decode-and-forward but also by applying amplify-and-forward to reduce the outage probability in final decoding of each layer. The performance of the proposed scheme is evaluated numerically in terms of the expected distortion at various relay locations using outage probabilities derived. The results show that the proposed scheme outperforms the conventional schemes in most cases of the relay location and the gain gets larger when the relay node is closer to the source node in particular.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.93-100
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• 2022

In the era of information overload on the Internet, the recommendation system, which is an indispensable function, is a service that recommends products that a user may prefer, and has been successfully provided in various commercial sites. Recently, studies to reflect the rating time of items to improve the performance of collaborative filtering, a representative recommendation technique, are active. The core idea of these studies is to generate the recommendation list by giving an exponentially lower weight to the items rated in the past. However, this has a disadvantage in that a time function is uniformly applied to all items without considering changes in users' preferences according to the characteristics of the items. In this study, we propose a time-aware collaborative filtering technique from a completely different point of view by developing a new similarity measure that integrates the change in similarity values between items over time into a weighted sum. As a result of the experiment, the prediction performance and recommendation performance of the proposed method were significantly superior to the existing representative time aware methods and traditional methods.

• 한국도로학회지:도로
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• v.17 no.3
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• pp.54-60
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• 2015

개발 시스템은 실용적 측면에서는 기존 수동형 장비에 비해 최대 20배(기존 2km/h, 개발장비 40km/h) 효율성을 향상시켰다. 국제민간항공기구(ICAO) 에서 권고하고 있는"Runway Surface evenness"에 대응할 수 있는 시스템을 개발하였으며, 개발 시스템은 국내 외 공항포장관리에 적용할 수 있는 시스템으로써 유관기관과 협력하여 향후 국내 외 장비시장에 진출할 수 있는 기술을 확보하였다.

• 월간 기계설비
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• no.9 s.206
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• pp.42-45
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• 2007

일반건설사들이 최근 시공 합리화를 통한 고부가가치 창출을 위해 건설현장의 전 과정을 데이터화한 정보시스템 개발 및 도입에 들어갔다. 건설사들이 선보인 현장관리시스템은 건설 프로젝트의 전 과정을 데이터화 및 공유하는 건설관리 정보화 시스템이다. 최근 들어 건설 산업의 전산화·정보화는 건설업무 진행 단계인 기획, 설계, 시공, 유지관리 절차에 따라 다양한 형태로 개발.활용되고 있다. 특히 시공단계에서 협력업체들 간의 다양한 정보공유로 불필요한 노동력 및 재정 낭비를 줄여 생산성 향상을 꾀하고 있다. 이번호에는 GS건설(주)의 현장관리시스템을 살펴본다.

• Annual Conference of KIPS
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• 2012.04a
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• pp.892-893
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• 2012

마이크로그리드 (microgrid)의 성능을 최적화하기 위해서는 마이크로그리드를 구성하는 분산 시스템간 협력적인 제어 기능이 요구된다. 멀티 에이전트 (multi-agent) 시스템은 이러한 마이크로그리드의 분산 제어를 위한 해결책 중 하나이다. 본 논문에서는 중앙 집중방식 멀티에이전트 시스템을 기반으로 마이크로그리드의 효율적인 제어를 위한 시스템을 설계하였다.

• Journal of the Economic Geographical Society of Korea
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• v.12 no.4
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• pp.477-493
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• 2009

This research aims to examine Korean regional innovation governance, find structural problems, and explore alternative strategies of regional innovation governance. Especially the alternative governance was searched through the case study of Daegu-Kyungbuk mobile cluster, of which formulation Samsung is the anchor institution. Regional innovation governance in this research is defined as a policy system to link knowledge generation & diffusion subsystem and knowledge application & exploitation subsystem, and institutional conditions to steer the system. "Social Capital Assessment Tool (SOCAT)" of the World Bank was utilized for the appreciation of cluster governance. The regional innovation governance of Daegu-Kyungbuk mobile cluster is characterized as production networks dominated by one-to-one relationship between Samsung and hardware/software developers, decentralized R&D networks and policy networks with multiple hubs. Major policy agents have not developed networks with local companies, and rare are interactions between the policy agents. Local companies, especially software developers, responded they have had experiences to cooperate for local problem solving and shared their community goal, however, the degree of trust in major local project leaders is not high. Local hardware/software developers with core technologies need to be cooperative to develop similar technologies or products in Daegu-Kyungbuk mobile cluster. Regional administrative actors, such as the City of Daegu and Kyungsangbuk-do, and diverse innovation-related institutes should build cooperative environment where diverse project-based cooperation units are incessantly created, taken apart, and recreated.

• The Korean Journal of Archival Studies
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• no.52
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• pp.119-170
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• 2017

This study aims to analyze the environment for the open-source records system and to identify the risk and requirements for the success of the strategy in Korea. For this, Chapter 2 presented a review of the strategic benefits of open source to public organizations, developers, and users. It also discussed the process of cooperatively developing and releasing the source code and the technology infrastructure supporting open source. In Chapter 3, six representative open-source projects in the field of records management were selected, and case studies were conducted. To derive comprehensive implications, we have divided the main development body of open-source projects into international organizations, international cooperation systems, national archives, and software development companies. We also analyzed the background and purpose of each project, the agents of development and funding, the governance model, the development period and cost, the business model and software architecture, the community composition, and the licensing strategy. Through this, we have derived four critical success factors. In terms of technology, a component-based design was required; therefore, we proposed a microservice architecture and a model-view-controller design pattern. Next, it was necessary to reestablish system requirements of records center and archives. Moreover, we also proposed a dual licensing strategy to allow developers to easily participate in open-source projects. Lastly, we emphasized a strong governance structure and an effective cooperation framework to create a sustainable community. For a record system to be open-source successfully in an organization-centered market, the roles of software developers and end users should be exercised more in the community. To achieve this, it is important to build various collaborative tools and development infrastructure from a planning stage to a centralized one.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.253-255
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• 2005

P2P 웹 캐싱 기술은 자신의 로컬 캐시에서 원하는 웹 객체를 찾지 못한 경우, 중앙 서버나 프락시 서버로부터 웹 객체를 받기 전에 P2P 네트워크에 참여하는 이웃으로부터 웹 객체를 받음으로써 기존의 서버-클라이언트 방식을 탈피하여 중앙 서버의 고장에 영향을 적게 받고, 중앙 서버로의 과도한 부하를 막아준다. 기존의 많은 P2P 웹 캐싱 시스템은 피어의 로컬 캐시 교체 정책으로 LRU기법을 사용한다. 하지만 이는 P2P 환경을 고려하지 않는 단순한 정책이다. 따라서 본 논문에서는 P2P 환경을 고려한 디렉토리 기반의 웹 캐싱 시스템을 통해서 P2P 협력적인 캐시 교체 정책을 제시하고 실제 웹 로그 트레이스로 시뮬레이션을 하여, 제안하는 교체 정책이 효과가 있음을 기술한다.