• International journal of advanced smart convergence
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• 제7권1호
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• pp.15-23
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• 2018

Spectrum allocation is a key operation in cognitive radio networks (CRNs), where secondary users (SUs) are usually selfish - to achieve itself utility maximization. In view of this context, much prior lit literature proposed spectrum allocation base on non-cooperative game models. However, the most of them proposed non-cooperative game models based on complete information of CRNs. In practical, primary users (PUs) in a dynamic wireless environment with noise uncertainty, shadowing, and fading is difficult to attain a complete information about them. In this paper, we propose a non-cooperative game joint hidden markov model scheme for spectrum allocation in CRNs. Firstly, we propose a new hidden markov model for SUs to predict the sensing results of competitors. Then, we introduce the proposed hidden markov model into the non-cooperative game. That is, it predicts the sensing results of competitors before the non-cooperative game. The simulation results show that the proposed scheme improves the energy efficiency of networks and utilization of SUs.

• Journal of electromagnetic engineering and science
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• 제6권3호
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• pp.176-181
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• 2006

Signal distortion due to the path loss, shadow, and multi-path fading is very serious in radio channel. In this paper, we propose CDMA-OFDM cooperative communication system based on DFP(Decode and Forward Protocol) to overcome these phenomena using spread spectrum technique, orthogonal sub-carrier, and the space diversity. We simulated proposed system under Rayleigh flat fading channel environment. A variety of simulation results reveal the cooperation can provide performance gain of up to 12 dB over direct communications in ideal inter-user case at BER of $10^{-3}$. And we can also confirm variation of diversity effect as channel environment changes.

• 컴퓨터교육학회논문지
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• 제11권5호
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• pp.19-32
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• 2008

창의적 문제해결에 대한 연구들은 온라인 환경에서나 면대면 환경 모두 대부분 개인적 측면에서 접근이 이루어지고 있어 협동적인 측면에서의 접근이 필요하다. 온라인 환경은 면대면 환경보다는 협동적 상호작용 촉진과 창의적 문제해결을 위한 효과적인 환경을 제공하고 있다. 따라서 본 연구는 협동을 통해 창의적 문제해결을 할 수 있는 온라인 지원 시스템을 개발하는 데 목적이 있다. 이를 위하여 본 연구는 첫째, 기존의 창의적 문제해결모형으로부터 온라인 환경에서 적합한 창의적 문제해결을 할 수 있는 모형을 도출하였다. 둘째, 통합된 창의적 문제해결모형을 토대로 협동 창의적 문제해결 모형의 온라인 지원 시스템을 위한 설계 원리를 개발하고 이에 기초하여 시스템을 개발하였다. 마지막으로 본 연구는 시스템의 향상을 위해서 형성평가를 실시하였다. 개발된 시스템은 협동 창의적 문제해결을 위한 효과적이고 효율적인 온라인 학습 환경을 제공해 줄 것이다.

• 한국컴퓨터정보학회논문지
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• 제11권2호
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• pp.285-294
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• 2006

분산 환경에서 다중 사용자간의 협력 작업을 효과적으로 지원하는 협력 작업에 대한 요구가 급격하게 증가하고 있다. 이러한 협력 작업은 그룹 통신 기술, 분산 처리 기술 등의 다양한 기술적 사항들이 해결되어야 하며, 협력 작업 응용이 갖는 공통적인 요구 사항들이 많이 존재하므로 응용을 개발할 때마다 이러한 요구 사항들을 중복하여 개발하는 것은 많은 개발 비용이 소요되며 중복 투자되는 부분이 많게 된다. 따라서, 협력 작업 응용이 공통적인 요구 사항들과 응용을 보다 경제적으로 개발할 수 있는 체계적인 개발 환경이 필요하다. 이 연구에서는 기존의 이동 에이전트의 조정 모델을 협력 작업응용에 적합하도록 개선한 계층형 역할 기반 조정 모델을 제안하고, 이를 이용해서 이동 에이전트 기반 협력 작업 응용을 위한 개발환경을 설계한다. 계층형 역할 기반 조정 모델은 이동 에이전트들의 다층형 그룹 개념을 제공하고, 각각의 그룹별로 효과적인 조정 정책 구현을 가능하게 하며, 그룹 단위 별로 역할을 부여해서 효과적인 협력 작업 응용 개발을 지원할 수 있다.

• Journal of Mechanical Science and Technology
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• 제14권9호
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• pp.956-967
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• 2000

In this paper, we explore the issues of force display in the cooperative virtual environment shared by multiple users distributed over the network with heterogeneous hardware platforms. The proposed method is to cope with the problem of small time delay and the difference of sampling rate in the distributed configuration. In the proposed approach the interaction forces of the participants are just treated as the independent sources of acceleration. Thus the action of a participant simply changes the acceleration of the virtual object and consequently the states of the virtual object will be updated. When the updated states are reported to all the participants, the information on the time of state changes is delivered, too. Employing the discrete state information updated by the other users, each user modifies his own virtual environment and pseudo-realtime simulation can be realized. Excluding the software interface and the communication technique, it is proposed the simulation method for the operation of respective users and the way of calculating the driving input to the display device. For experimental verification we construct a cooperative virtual environment shared by two remote users and outline the results of experiments.

• 한국주거학회논문집
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• 제14권6호
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• pp.193-204
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• 2003

In connection with the plan for improving the residential environment gradually by analyzing the present condition of the reconstruction and parcel form of the housing area in a inner area, the main objective of this research is to develop a cooperative urban housing model based on the neighborhood agreement. The parcel form has a structure that is inappropriate for individual reconstruction； thus, the substantial improvement only through the residential environment improvement project has its limitations. As an alternative plan to resolve such limitations, I proposed a system that enables step-by-step reconstruction within the small-scaled blocks through the annexation of the land based on the neighborhood agreement. Nonetheless, I realized that it is difficult to apply such reconstruction system to individual housing. Therefore, I presented a design concept on the cooperative urban housing project as a residential form for the reconstruction inside blocks. A model plan vouches for its effectiveness. To apply substantially the cooperative urban housing plan based on the neighborhood agreement, we need to supplement the sectional plan system.

• 대한안전경영과학회지
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• 제12권2호
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• pp.125-132
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• 2010

In accordance with the trend for cooperation of related company, BOM (Bill of Materials) has become an important factor in the manufacturing of production. BOM manages a various basic information of design, production, and process and so on. Especially, automobile industries are related to many company, they build a cooperative system from the communication of information. In this study, we have analyzed a BOM structure of a well-used automobile part industry and proposed a structure of engineering BOM, manufacturing BOM, process BOM for cooperative environment. A proposed various BOM structure are flexible in responding to the situation of structure alternations for automobile part. And also they include in environment factors. It is expected that these BOM structure will be used to basic template in automobile part industry which could be loaded with cooperative hub-system.

• 한국항행학회논문지
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• 제25권6호
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• pp.450-455
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• 2021

본 논문에서는 V2X 통신 기반의 상용차 자율협력주행 플랫폼 평가환경 구축 연구의 내용을 소개한다. V2X 통신 기반의 자율협력주행 플랫폼 평가를 위해서는 다양한 주행 시나리오를 적용할 수 있는 도로 및 V2X 인프라 등의 테스트베드 구축과 함께 시험평가를 위한 각종 제반 규격 및 표준, 지침 등이 개발되어 피시험자에게 제공되어야 한다. 또한, 이를 기반으로 실제 시험평가를 진행할 수 있는 각종 레퍼런스 장비와 시험장비 등이 개발되어야 한다. 본 논문에서는 V2X 통신 기반 상용차 자율협력주행 플랫폼 평가환경을 구성하기 위해 개발된 다양한 기술과 규격, 장비 그리고 구축 인프라를 소개한다.

• 영어어문교육
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• 제10권1호
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• pp.127-152
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• 2004

The purpose of this study is to elaborate design strategies for a Web-based self-directed cooperative distance language learning community. Research was done regarding the theoretical foundations for self-directed cooperative language learning and Web-based learning communities. The components of a Web-based community for self-directed cooperative language learning system are also investigated. As a result of this study, design strategies for Web-based communities are suggested. There are performance and supporting environments(synchronous/asynchronous) for self- directed cooperative language learning. There are also cultural experiences and communication factors in the performance field. Furthermore, matching communicators, finding and offering information, language learning content and other supporting agents are important in the supporting environment.

• 수산경영론집
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• 제33권2호
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• pp.99-125
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• 2002

Fisheries cooperative requires dual characteristics in performing its original function. Economic characteristic as an business enterprise and democratic characteristic as cooperative entity need to complete its objectives and survive in the complex rapidly-changing environment. After IMF crisis, fisheries cooperative received enormous government's financial support and credit-business department is perfectly under government's control. Regional fisheries cooperative also faces business failure, therefore pure cooperative movement can't save the fisheries cooperative. Economic characteristic as an business enterprise is more emphasized than democratic characteristic as cooperative entity in recent years. The theory of corporate ownership and governance can be applied to explain the ownership and governance of fisheries cooperative because fisheries cooperative is now similar to an business enterprise. During the IMF crisis the board, the auditors and the minority shareholders in business enterprise were revealed to be powerless against the mighty influence of controlling shareholders. Unconstrained discretion exercised by those controlling shareholders not only led to the firms'insolvency, but also brought down the country's financial system. During the past few years, Korea has experienced many institutional changes regarding its corporate governance structure. The introduction of outside directors, the strengthening of minority shareholders' rights, and enhanced accounting transparency are achieved to improve the efficiency of economic system. Investors, including institutional and individual, also seem to be more aware of governance issues now. Credit-business department of fisheries cooperative is recommended to introduce the institutions same as the case of the corporate governance structure. Fisheries cooperative except economic and credit-business department requires other prescriptions because it is emphasized as democratic cooperative entity. But we should be careful to interpret the ownership and governance structure because they are products of nations, eras and organizations.