• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(D)
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• pp.213-214
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• 2011

This paper presents a distributed relay selection algorithm for cooperative communication. The algorithm separates the decision making into two simple steps, decision making for employing cooperative communication and decision making for relay selection.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1288-1293
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• 2009

Performing 'Mega Project' in which various stakeholders are involved is difficult to control due to the respective conflicting objectives. Urban regeneration which is being challenged issue in various ways can be defined as the mega project. Since the mega project like urban regeneration a long-continued project and includes a lot of participants whose benefits conflict, cooperation among stakeholders is essential. Moreover, as the project goes, diverse decision making situations which require collaboration happen, and if proper decision making cannot be given at that time, the whole project would have critical effects. Also, since each activity concerns numerous stakeholders, prompt decision making is difficult in the mega project. Therefore, the objective of this study is to support stakeholder's cooperative decision making in order for conducting successful project. For the purpose of the paper, the concept of cooperation in mega project is redefined and a cooperative decision making framework is suggested. Also, the term of governance, which means cooperative mechanism based on the mutual trust, information sharing and partnership, is applied to the newly defined cooperation. The suggested cooperative decision making framework contains the structure of stakeholders in urban regeneration project which enables participants to understand the relationship among bodies and checklists for supporting decision making appropriately. The application of the framework proposed in this research is expected to contribute subjects' suitable decision making by providing proper information in a timely manner.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.1144-1149
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• 2005

This paper presents how to establish the decision support model for the cooperative design in order to improve design coordination and optimize the building system. With this view, the paper presents the method that analyzes decision making participants of each building system on drawings. It also presents the combination evaluation method from the viewpoint of performance, cost and constructability to improve the decision making process in cooperative design.

• 한국전자파학회논문지
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• 제22권4호
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• pp.423-429
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• 2011

협력 스펙트럼 센싱은 스펙트럼 센싱의 신뢰성 및 정확도를 높이기 위해 다수의 CR 기기들이 정보를 공유하여 면허 사용자를 검출하는 방식이다. 이때, CR 기기의 센싱 결과를 융합하는 방식에 따라 경판정 방식(hard decision method)과 연판정 방식(soft decision method)으로 구별할 수 있다. 본 논문은 면허 사용자와 CR 기기 사이의 거리에 따른 가중치가 적용된 결합 방식(Distance based Weight Combining: DWC)을 사용하여 에너지 검출기반 협력 스펙트럼 센싱을 제안하고, 이에 따른 분석 및 모의 실험 결과를 나타낸다. 면허 사용자의 신호는 OFDM 기반의 시스템을 가정하였으며, 면허 사용자와 CR 기기 사이의 무선 채널은 가우시안(Gaussian) 채널로 모델링하였다. 에너지 검출법을 위한 임계값은 각 채널의 SNR(Signal to Noise Ratio)에 따라 다르게 적용되었으며, 각 채널의 잡음 신호의 평균값으로 가정하였다. DWC를 적용한 협력 스펙트럼 센싱을 수행한 결과, 거리에 따라 다양한 검출 확률을 나타낸 단일 센싱에 비해 비교적 안정된 검출 확률을 나타내는 것으로 알 수 있었으며, 동일 이득 결합을 반영하여 협력 스펙트럼 센싱을 수행한 것보다 우수한 스펙트럼 센싱을 나타내었다.

• 한국전자파학회논문지
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• 제22권4호
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• pp.416-422
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• 2011

본 논문에서는 개별 센싱 결과를 결합하기 위해 센싱의 성능은 연판정 방식보다 낮지만, 시스템의 부담이 적고 비교적 단순한 방식인 경판정 방식을 적용하였으며, 센싱의 성능을 높이기 위해 각 CR 기기의 검출 확률을 반영하여 가중치를 설정하고, 계산된 가중치가 개별 센싱 결과에 재반영되어 결합하는 최적화된 경판정 방식을 제안한다. 기존의 경판정 방식과 달리 가중치를 적용하여 센싱 성능을 높이도록 하였고, 모의 실험 및 분석을 통하여 성능을 나타내었다. 1차 사용자의 신호는 OFDM 기반의 시스템을 가정하였고, 1차 사용자와 CR 기기 사이의 무선 채널은 가우시안(Gaussian) 채널로 모델링하였다.

• Journal of Communications and Networks
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• 제13권3호
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• pp.257-265
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• 2011

In this paper, a cooperative relaying protocol called soft-decision-and-forward (SDF) with multiple antennas in each node is introduced. SDF protocol exploits the soft decision source symbol values from the received signal at the relay node. For orthogonal transmission (OT), orthogonal codes including Alamouti code are used and for non-orthogonal transmission (NT), distributed space-time codes are designed by using a quasi-orthogonal space-time block code. The optimal maximum likelihood (ML) decoders for the proposed protocol with low decoding complexity are proposed. For OT, the ML decoders are derived as symbolwise decoders while for NT, the ML decoders are derived as pairwise decoders. It can be seen through simulations that SDF protocol outperforms AF protocol for both OT and NT.

• 플랜트 저널
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• 제7권4호
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• pp.67-76
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• 2011

Two main features of the recent building project are the enlargement of the size and the technological complexity. Due to these features, the number or the size of organizations participating in building project is also increasing and the relationships between the organizations are becoming more interdependent than ever. Owing to these features, some delays or errors in the decision-making process in the phase of planning of a building project may influence many subjects related to the project. The most important factor for a successful project is to arbitrate confrontations and build cooperative relationships between parties who have different interests with one another in the project. Efforts were made to find out general features of building project and the features in the phase of planning in order to set a direction of this research. To solve problems in the phase of planning, the concept of 'cooperative design', which means that different features and interests of various organizations should be reflected from the phase of planning, was introduced. By introducing cooperative design in building projects, more rapid and objective decision-makings are possible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.649-664
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• 2011

Cooperative spectrum sensing (CSS) with decision fusion is considered as a key technology for tackling the challenges caused by fading/shadowing effects and noise uncertainty in spectrum sensing in cognitive radio. However, most existing solutions assume an error-free decision transmission, which is obviously not the case in realistic scenarios. This paper extends the general decision-fusion-based CSS scheme by considering the fading/shadowing effects and noise corruption in the common control channels. With this more practical model, the fusion centre first estimates the local decisions using a binary minimum error probability detector, and then combines them to get the final result. Theoretical analysis and simulation of this CSS scheme are performed over typical channels, which suggest some performance deterioration compared with the pure case that assumes an error-free decision transmission. Furthermore, the fusion strategy optimization in the proposed cooperation model is also investigated using the Bayesian criteria. The numerical results show that the total error rate of noisy CSS is higher than that of the pure case, and the optimal values of fusion parameter in the counting rule under both cases decrease as the local detection threshold increases.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권5호
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• pp.461-474
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• 2009

The cognitive radio (CR) technique is a useful tool for improving spectrum utilization by detecting and using the vacant spectrum bands in which cooperative spectrum sensing is a key element, while avoiding interfering with the primary user. In this paper, we propose a novel cluster-based cooperative spectrum sensing scheme in cognitive radio with two solutions for the purpose of improving in sensing performance. First, for the cluster header, we use the double adaptive energy thresholds and a multi-bit quantization with different quantization interval for improving the cluster performance. Second, in the common receiver, the weighed HALF-voting rule will be applied to achieve a better combination of all cluster decisions into a global decision.

• 인터넷정보학회논문지
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• 제12권2호
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• pp.1-8
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• 2011

본 논문에서는 무선인지시스템에서 스펙트럼 센싱을 효율적으로 수행하기 위한 선택적 협력 스펙트럼 검출 기법을 제안한다. 제안된 알고리즘에서는 각 무선인지 사용자가 자신의 유도비(likelihood ratio)를 기반으로 자신의 센싱 신뢰도를 평가하고, 센싱 신뢰도에 따른 타이머를 활용하는 경쟁기반의 센싱 결과 보고 메커니즘을 활용한다. 이를 통해, 제안된 선택적 협력 스펙트럼 기법에서는 가장 높은 센싱 신뢰도를 갖는 무선인지 사용자만이 국부 스펙트럼 센싱값을 융합센터로 전송함으로써, 스펙트럼 센싱의 성능을 일정한 레벨로 유지하고, 협력 스펙트럼 센싱의 단점인 제어 트래픽 및 협력 센싱 시간을 줄이는 이점을 갖는다.