• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.101-108
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• 2013

In this paper, we propose a method in which the negative acknowledge (NACK) message is used as command for cooperation and spectrum sharing. This allows for an automatic request for cooperation and sharing when the direct link of the primary user is in outage, and also allows for saving the number of control messages in cooperation-spectrum sharing based paradigm. In the sharing phase, the selected relay shares a power fraction of $1-{\alpha}$ for secondary transmitted signal while the remaining of ${\alpha}$ is for primary retransmitted signal. In the case of no relay collected, primary transmitter uses NACK as a command to retransmit the signal with fully power fraction (${\alpha}=1$). Both systems are assumed to employ BPSK signals. In this scheme, we propose the joint optimal decoding in the secondary user. The frame error rate (FER) performance at both systems is then analyzed. The theoretical and simulation results validate the analysis and confirm the efficiency of the protocol.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.89-99
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• 2010

Military Barracks and Bachelor Officer's Quarters are public buildings representing architectural characteristics with repeating the same room modules. These buildings require easy dismantling and reusing for the next generation' military re-organization. For these reasons, since 2005, the modular construction has been applied to military buildings. The most important factors required for modular military buildings are standardization, lowcost construction and reusable construction method. However, conventional modular building system have not been matched with these requirements. This study suggests a new modular system for Bachelor Officer's Quarters using Six-sigma design tool. To reflect the voices of customers, market study and surveys were carried out. Through the QFD, the voices of customers were converted into quality characteristics of building system for BOQ. The various design concepts meeting customer's requirement were derived by the QFD and Pugh matrix methodology. The proposed modular building system shows 80% increased factory production rate and 62% decreased weight of steel frame as compared with the conventional modular building system.