• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.348-357
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• 2007

One of the major issues in recent researches on wireless sensor networks is to reduce energy consumption of sensor nodes operating with limited battery power, in order to lengthen their lifespan. Among the researches, we are interested in the schemes in which a sensor node periodically turns on and off its radio and requires information on the time when its neighbors will wake up (or turn on). Clock synchronization is essential for wakeup scheduling in such schemes. This paper proposes three methods based on the asynchronous averaging algorithm for clock synchronization in sensor nodes which periodically wake up: (1) a fast clock synchronization method during an initial network construction period, (2) a periodic clock synchronization method for saving energy consumption, and (3) a decision method for switching the operation mode of sensor nodes between the two clock synchronization methods. Through simulation, we analyze maximum clock difference and the number of messages required for clock synchronization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.304-310
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• 2006

This paper evaluates the performance of three types of data delivery mechanisms in clustered sensor networks, as a basic research to develop an energy efficient topology management scheme. In the first mechanism, one node per cluster(clusterhead) turns on its radio(or wakes up) to transmit and receive RTS/CTS/DATA/ACK messages, but in the second one, k nodes per cluster wake up and participate in the message exchange. In the last mechanism, clusterheads turn on the radio to exchange RTS/CTS messages, and if a clusterhead receives RTS containing its cluster m as a destination, it makes k nodes in the cluster hun on the radio to receive DATA and transmit ACK. Through simulation, we show the energy consumption of the three types of data delivery mechanisms as functions of the number of active nodes per cluster, offered load, and packet loss probability.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.427-428
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• 2017

현재 사격 및 전술훈련에 반드시 필요한 실전적인 소대급 이하에 적용 가능한 범용의 특화된 레이저 발사기를 활용한 사격 및 전술훈련 시스템의 개발이 필요하다고 볼 수 있다. 본 연구에서는 사격 및 전술훈련에 필요한 개발 규격 및 사양은 군부대 표준규격을 적용하고, 개발 제품에 대한 성능평가는 군부대 및 경찰사격장 및 전술훈련장에 설치하여 사용자 요구사항을 기준으로 테스트 및 평가하여, 소대급 이하 전문 사격 및 전술훈련용 장비를 개발한다. 실질적인 소대급 이하 사격 및 전술훈련용으로 레이저 발사기, 격발장치, 감적장치, 각종 제어모듈 개발을 통하여 유 무선 송수신을 체계화하여 통합 제어 시스템을 구축함으로써, 실제 총기에 레이저 발사기를 부착하여 사격 및 전술훈련용으로 다양한 기술 확보를 통하여 관련 시장 선점 및 관련 산업활성화에 기대할 것으로 전망된다.