• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1062-1064
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• 2009

지하 산업시설에 u-기반 지능형 서비스를 제공하기 위해 주요습득인자인 상황정보를 목적지에 전송할 수 있는 무선 인프라 구축이 요구되며, 이제까지 유비쿼터스 분야에서 공통기술 위주로 연구 및 개발되었기 때문에 시설별 특성을 고려한 인프라 구축 및 서비스는 부족한 상황이다. 본 논문은 도시가스 지하 폐쇄환경인 가스밸브박스와 전용통신 시설이 존재하는 정압기까지 상황정보 전송을 위해 환경특성을 추출하고, 적용 가능한 무선 방식을 시험하며 환경특성과 시험결과에 따라 적절한 무선 상황정보 전송방식의 토대를 제공한다.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.41-46
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• 2018

The wireless sensor network system has the advantage of confirming the behavior of the entire facility by improving the disadvantages of conventional monitoring system. As a result, it is widely proposed as safety diagnosis and measurement of structures, water management systems, and management systems for dam structures. However, there is a lack of research that can evaluate the condition of facilities such as safety at the same time as monitoring. In this study, it is proposed a wireless sensor network system which can evaluate the behavior characteristics of facilities and evaluate the safety status for improving the technical disadvantages on conventional monitoring system. The geotechnical risk factors for the reservoir dam facility were evaluated and the limit values for the risk factors causing the failure of the facility were set. In other words, the system was set up so that the risk factors can be measured and the limit status can be evaluated immediately for each factor. In this study, numerical analysis is carried out for seepage and slope stability analysis using the typical cross section for reservoir dams. The stress-porewater coupling finite difference numerical analysis is performed for establishing the limit displacement for reservoir dam structures. It is developed a system that can estimate the time to reach the critical value by regression analysis using the measured datas.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.232-235
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• 2006

일반적으로 선형 토폴로지 (chain topology) 무선메쉬네트워크의 종단간 최대 전송률은 경쟁관계 그래프 (contention graph)에 기반하여 트래픽 병목 구간의 노드 개수와 1 홉 링크의 평균 전송률을 결정하여 계산하는 방식이 널리 이용된다. 본 논문은 평균을 이용한 방법은 IEEE 802.11 DCF (Distributed Coordination Function)를 MAC 프로토콜로서 사용하는 무선메쉬네트워크에서 정확성에 한계가 있음을 보이며, 이와 같은 정확성의 한계를 유도하는 인자로서 전송률의 편차를 소개한다. 또한 전송률 편차를 고려하여, 단일 선형 토폴로지에서 종단간 최대 전송률을 구하는 방법을 ns2 시뮬레이션을 통해 검증한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.87-92
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• 2015

In this Paper, we proposed optimization of system performance, optimal splitting factor ${\alpha}$ applied to power splitting protocol with relay protocol with decode and forward undergo co-channel interference. We can possible to optimize and maximize the channel capacity of the receive performance and the efficiency of the network through optimal factor of splitting protocol. We verified BER performance and Channel capacity and Outage probability for the proposed scheme over Rayleigh fading through Monte-Carlo simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.225-236
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• 2002

In this paper, to counteract a cross-polarization interference caused by co-channel dual polarization technique of digital radio relay system(DRRS), we analyze the theoretical model and digital design of cross-polarization interference canceller(XPIC). In addition a complex adaptive time domain equalizer(ATDE) is designed using a finite impulse response filter, and the structure of XPIC and its control method are also illustrated including ATDE. Our computer simulation shows that about 25 dB signature and more than 23 dB XPIC improvement factor can be obtained with XPIC and ATDE. In order to verify the operation of designed XPIC, we review the simulated results in view of tap number, algorithm convergence, system signature, and XPlC improvement factor in connection with 64-QAM DRRS with co-channel dual polarization.

• Spatial Information Research
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• v.8 no.1
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• pp.85-99
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• 2000

Accurate information on habitat distribution of protected fauna is essential for the habitat management of Korea, a country with very high development pressure. The objectives of this study were to develop a habitat suitability model of wild boar based on GIS and logistic regression, and to create habitat distribution map, and to prepare the basis for habitat management of our country s endangered and protected species. The modeling process of this restudyarch had following three steps. First, GIS database of environmental factors related to use and availability of wild boar habitat were built. Wild boar locations were collected by Radio-Telemetry and GPS. Second, environmental factors affecting the habitat use and availability of wild boars were identified through chi-square test. Third, habitat suitability model based on logistic regression were developed, and the validity of the model was tested. Finally , habitat assessment map was created by utilizing a rule-based approach. The results of the study were as folos. First , distinct difference in wild boar habitat use by season and habitat types were found, however, no difference in wild boar habiat use by season and habitat types were found , however, ho difference by sex and activity types were found. Second, it was found, through habitat availability analysis, that elevation , aspect , forest type, and forest age were significant natural environmental factors affecting wild boar hatibate selection, but the effects of slope, ridge/valley, water, and solar radiation could not be identified, Finally, the habitat at cutoff value of 0.5. The model validation showed that inside validation site had the classification accuracy of 73.07% for total habitat and 80.00% for cover habitat , and outside validation site had the classification accuracy of 75.00% for total habitat.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.954-961
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• 2011

To apply Wi-Fi technique to the Broadcast field, we have to study features of IEEE 802.11 Broadcast packet. IEEE 802.11 Broadcast technique cannot guarantee successful packet delivery than IEEE 802.11 Unicast. A promising solution to this problem is the use of FEC(Forward Error Correction) mechanisms. However, the adjustment of the FEC redundancy rate is not a trivial issue due to the dynamic wireless environment. In order to explore the above issues we conducted an experimental study of the packet loss behavior of the IEEE 802.11g protocol. In order to study, we implemented a broadcast test bed. Based on the experimental results, we provide guidelines on wireless lan parameters(packet size, transmission rate(11g), background traffic). From this experimental study, we provide FEC redundancy rate.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.178-180
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• 2012

차량간 무선 통신 환경인 VANET에서 중요하게 여겨지는 문제점 중에 하나는 메시지 브로드캐스팅시 발생 가능한 메시지 폭주 현상(Broadcasting Storm)이다. 최근 무선 애드 혹 네트워크나 이동 애드 혹 네트워크(MANET) 환경에서 이를 해결하기 위해 Connected Dominating Set(CDS) 기법을 제안하여 최대한 중복된 메시지가 전달되지 않도록 하였다. MANET의 한 분야인 차량 애드 혹 네트워크(VANET)에서도 이러한 CDS 가상 백본 망을 이용하면 효율적인 메시지 전파를 기대할 수 있지만, 그 동안의 CDS 생성 기법은 노드의 속도와 방향이 고려되지 않았기 때문에 안정적인 CDS 망을 유지할 수 없다. 본 논문에서는 VANET 환경에 적합한 CDS 환경을 만들기 위해 노드의 이동성을 고려한 기존의 Timer-based CDS 생성 기법에 속도와 방향 두 가지 인자를 추가하여 Velocity-based Multi-CDS(VM-CDS) 기법을 제안하였고, 시뮬레이션을 통해 기존 방안보다 더 안정적으로 유지됨을 입증하였다.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.449-454
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• 2012

According to the development of the ubiquitous computing technic today, the sensor base system is becoming a big issue in IT fields. This study is to develop a smart weather watching system which allows us to carry out temperature measuring without regard to location and altitude using the sensor devices. this system is composed of the wireless receiver module(PC base) and the wireless measuring module(ATmega2560 base).

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.19-21
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• 2006

무선 센서 네트워크에서 많은 라우팅 프로토콜이 연구되고 있음에도 불구하고 다양한 응용 프로그램의 요구사항을 만족할 수 있는 최적의 방법은 없다. 본 논문에서는 응용 프로그램들이 요구하는 라우팅 프로토콜의 중요한 영역 인자인 시간성 신뢰성 그리고 에너지 상태를 모두 고려한 라우팅 프로토콜을 제안한다. 제안된 라우팅은 해당 가지 영역에 대해 각 노드의 라우팅 cost를 계산하며 해당 영역의 인자를 기준으로 절충한 결과를 이용하여 다음 노드를 선택한다. 따라서 각 패킷은 적절한 서비스를 받을 뿐만 아니라 인접 노드의 정보만을 사용하므로 Scalable 하다. 실험 결과는 각 영역에 대한 단일 요구에 대해서는 best-effort service를 하며 복합적 요구에 대해서는 절충 알고리즘을 거쳐 적합한 서비스를 제공함을 보인다.