• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1131-1136
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• 2020

Cooperative networks enhance the performance of communication systems by combining received signals from the several relay nodes where the source node transmits signals to relay nodes. In this paper, we analyze the effect of resource allocation in cooperative networks. We assume that the cooperative networks use the conventional modulation scheme between the source and relay nodes, and adopt space-time code between the relays and destination node. Both the synchronous and differential modulations are applied for the conventional scheme and differential modulation is used for the space-time code. We consider relay location and energy allocation for resource allocation, and the performance of cooperative networks depending on the number of relay is also investigated.

• Proceedings of the CALSEC Conference
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• 1998.10a
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• pp.175-186
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• 1998

국내 섬유ㆍ의류산업의 고비용/저효율 구조를 혁신하기 위해서는 산업간 공급사슬을 효율적으로 관리할 수 있는 QR 시스템의 도입이 불가피할 것으로 보인다. QR 시스템의 성공적인 도입을 위해서는 정보기술적 측면에서 효과적이며 통합적인 정보 파이프라인의 구현, 그리고 기업문화적 측면에서 서로 다른 기업문화와 산업환경하에서의 기업 상호간 전략적 협력관계의 창출이 필수적 요건이라고 하겠다.

• ICROS
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• v.3 no.5
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• pp.17-30
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• 1997

개방화 연구라는 것은 그 자체가 특정 제품을 구체적으로 개발하는 것이 아니라, 그 가능성 제공에 있음을 유의할 필요가 있다. 개방화 기술은 향후 새로운 기술장벽으로 작용할 수도 있으므로 우리나라도 관련 분야의 연구를 조직화하여 선진제국의 개방화 연구와 협력, 교류할 필요가 높아지고 있다. 참고로 일본의 OSEC II 프로젝트는 해외 연구기관 및 기업이 참여할 수 있도록 개방되어 있다고 한다.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.48-52
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• 2010

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.33-36
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.15-20
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• 1986

This paper gives a survey to robotics research and application in France. After a overview of French position in world market, an analysis on the R & D effort and technical peculiarity are presented. In view of the increasing needs for international co-operation in advanced robotics, the author points out the French option as a diversifing source.

• Korean Journal of Construction Engineering and Management
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• v.4 no.2 s.14
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• pp.66-73
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• 2003

Building construction projects are performed by a number of sub-contractors specialized in diverse trades. Therefore information management among these constituents is quite challenging especially due to exponentially increasing manpower and material resources. In recognition of the importance of information management in project sites a number of systems have been suggested, but the application is limited one of the main reason is that general contractors use these systems and sub-contractor's participation understanding and financial ability are limited. Besides other problems such as loss along communication channel, distortion of information due to inefficient input device and tremendous amount of time and labor are required for collection analysis, and management of information to prepare a daily-report. Therefore the Purpose of this study is to improve reporting process through analyzing current daily reporting system. This paper also suggests the direction of the improved daily reporting system to enhance the performance of construction projects through incorporating sub-contractor's participation in daily reporting system.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.59-66
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• 2016

India and China are capable of developing indigenous space launch vehicles, with the rocket technology transferred from the U.S., Western countries, and the Soviet Union, in the 1950s and 1960s. Barring the early 1990s, both countries are absent in the missile nonproliferation regime, and have no major space cooperation records with the U.S., since the establishment of the Missile Technology Control Regime in 1987. With the advent of the $21^{st}$ century, historic progress has been made in the U.S.-India space cooperation, which includes using Indian launch vehicles to launch U.S.non-commercial satellites. However, the U.S. is skeptical with regards to space cooperation and using Chinese space launch vehicle services. In this paper, we present the U.S. nonproliferation policy applied on launch vehicles of India and China, and different aspects of the policy will be examined to draw implications on Korean space activities.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.45-50
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• 2010

In this paper, we analysis the performance of cooperative spectrum sensing with distance based weight for cognitive radio (CR) systems and CR systems sense the spectrum of the licensed user by using a energy detection method. Threshold is determined in accordance with the constant false alarm rate (CFAR) algorithm for energy detection. The signal of licensed user is OFDM signal and the wireless channel between a licensed user and CR systems is modeled as Gaussian channel. From the simulation results, the cooperative spectrum sensing with distance based weight combining (DWC) and equal gain combing (EGC) methods shows higher spectrum sensing performance than single spectrum sensing does. And the detection probability performance with the DWC is higher than that with the EGC.