• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.10a
• /
• pp.141-145
• /
• 2004

The residual propellant of satellite is the primary factor of satellite life. This propellant used in the satellite is stored as liquid in tanks. But it is very difficult to accurately measure propellant to be used for maintaining of satellite by an irregular influence of environment. In this paper, a new method of gauging propellant residual of satellite employing multi-tank system by measuring mass flow of thermal pumping liquid propellant is presented. In cases of being connected between tanks, propellant in tanks move by temperature difference of tanks. If propellant mass flow is measured at line between tanks, residual propellant in tanks is able to be estimated.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.05a
• /
• pp.1493-1496
• /
• 2005

연결형 dominating set기반의 라우팅 알고리즘에서 잦은 dominating set의 재구성은 루트 손실로 인한 전송 에러를 발생시키기 때문에, 노드의 잔여 전력량과 이동성을 고려하여 게이트웨이 노드를 선택하여야 한다. 또한 같은 지역에 노드가 집중되어 있다면 매체를 공유하는 무선 네트워크의 특성상 병목으로 인한 충돌 및 지연 등이 야기 될 가능성이 크다. 따라서 본 논문에서는 노드의 잔여 전력량 및 이동성, 이웃 노드수의 가중 가산 값에 비례하여 이웃 구성 통보 메시지 (neighbor set advertisement message)의 브로드캐스팅을 지연시키는 방법을 통해 연결형 dominating set의 재구성을 최소화 하여 신뢰성 있고 효율적인 데이터 전송을 보장하는 새로운 연결형 dominating set 구성 방법을 제안하고 다양한 상황에서의 실험을 통해 그 성능을 비교 평가하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1173-1178
• /
• 2012

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.27-30
• /
• 2012

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases of header re-elected problem, decreases of header re-elected problem and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header because the remaining energy level goes low, it sends a beacon message to neighbor member nodes and the second header will serve as the cluster header.

• Journal of the Korean earth science society
• /
• v.21 no.2
• /
• pp.128-136
• /
• 2000

To understand the variation and transport pattern of suspended matters, salinity, tidal current and suspended matters in semiclosed Muan Bay have been monitored during winter and summer. The suspended matters show considerably seasonal variations with low concentration and homogeneity in the water column during winter season, but with high concentration and layering during summer season. Particularly, during summer season, the freshwater and the suspended matters influxed by the gate operation of the Youngsan River sea-dike are transported northward in accordance with the would flow into the inner-bay by relaxed flood currents after the construction of sea-dike and sea-walls in the Mokpo coastal zone. But, in the south bay-mouth, those matters outflow through the bay-mouth, resulting from tidal ebb dominance and asymmetry in the west bay-mouth. The residual suspended matter flux is much higher in the south bay-mouth(-0.0955kg/m ${\cdot}$ sec) than that of west bay-mouth(0.0078kg1m ${\cdot}$ sec). Accordingly, The Muan Bay is interpreted as erosion-dominated environments, and the erosion somewhat progresses in the intertidal flat of the bay.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.224-227
• /
• 2012

In the Cluster-Based Routing Protocol (CBRP), a cluster header in each cluster is selected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP selects a cluster header without considering the remaining energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be selected frequently. In this paper, we propose the advanced protocol which prolongs the lifetime of the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining energies of all of nodes are compared with one another, and the node with the highest energy is selected as the cluster header.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.1
• /
• pp.63-71
• /
• 2013

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other member nodes do because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exist problems that the cluster header has short average lifetime, and a new cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases the problem of re-electing the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header any more because the remaining energy level goes low, it sends a beacon message to neighbor member nodes, then the second header will serve as the cluster header.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.5B
• /
• pp.274-286
• /
• 2005

In this paper, we propose a new power-efficient and reliable connected dominating set based routing protocol in the mobile ad hoc networks. Gateway nodes must be elected in consideration of residual energy and mobility because frequent reconstruction of connected dominating set result in transmission error for route losses. If node density is high, it results in a lot of contentions and more delays for network congestion. Therefore, in this paper, we propose a new construction method of connected dominating set that supports reliable and efficient data transmission through minimizing reconstruction of connected dominating set by delaying neighbor set advertisement message broadcast in proportion to weighted sum of residual energy, mobility, and the number of neighbor nodes. The performance of the proposed protocol is proved by simulation of various conditions.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.51 no.2
• /
• pp.15-27
• /
• 2009

토지이용변화가 수질에 미치는 영향을 평가하기 위하여 비점오염모형이 광범위하게 사용되고 있다. 본 연구에서는 최적관리기법이 수문 수질에 미치는 영향을 평가하기위한 통합모형시스템을 개발하였다. 통합모형시스템은 DANSAT (Dynamic Agricultural Non-point Source Assessment Tool)과 사용자 인터페이스로 구성되어 있다. DANSAT은 분포형 연속 강우사상 모형으로서 농업소유역에서의 유출량, 유사량, 농약 물질의 이동기작 등을 모의한다. DANSAT은 크게 동적변수 부모형, 수문 부모형, 유사 이용 부모형, 농약 물질 이동 부모형등 4개의 부모형으로 구성되어있다. 동적변수 부모형은 토양의 특성, 작물의 생장 및 작물 잔여물질의 분해 등을 모의하는 하부모형으로 구성되어있으며, 토지 이용 변화에 관계되는 내부 변수들의 시간적 변화를 모의한다. 수문 부모형은 차단, 증발산량, 침투량, 침루량 등을 모의하는 격자 단위 프로세스와 지표유출, 중간유출, 기저유출 및 하천에서의 물의 이동을 모의하는 유역 단위 프로세스로 구성되어있다. 유사 이동 부모형은 세류간 (interrill) 토양입자의 분리, 세류 (rill) 및 하천내의 토양분리, 운송가능량 등을 모의하며, 농약 물질 이동 부모형은 농약의 분해, 평형, 식물에 의한 흡수, 침출 등을 고려하여 농약 물질의 이동을 모의한다. 입력변수는 최적관리기법의 시 공간적인 변화를 고려할 수 있도록 계층구조로 구성하였다. 유역출구에서의 결과 출력 뿐만 아니라, 유역전체에 걸쳐 지표면과 지하수면 사이에서 물 및 오염물질의 이동량 분석을 위한 출력 및 격자단위의 상세 결과 출력을 통하여 최적관리기법을 평가하고 분석할 수 있다. 한편, 사용자 인터페이스는 모형의 구동을 위해 요구되는 광범위한 시 공간 입력 자료를 기존에 존재하는 데이터베이스를 이용하여 생성할 수 있도록 개발되었다.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.19-22
• /
• 2000

최근 이동전화의 사용이 급격히 확산됨에 따라 핸즈프리 단말기를 이용한 전화통신의 필요성이 대두되고 있다. 차량내 핸즈프리 통신상황의 경우 근거리에 위치한 스피커와 마이크로폰의 커플링에 의해 발생하는 음향반향과 차량내에 존재하는 배경잡음은 통화 품질을 크게 저하시킨다. 본 논문에서는 이동통신에 적합한 음향반향제거기와 잡음제거기의 결합시스템을 제안하고, 이를 고정 소수점 DSP를 이용하여 실시간 구현하였다. 실시간 구현을 위하여 음향반향제거기에는 NLMS 알고리즘에 의해 구동되는 제한된 차수의 적응반향제거기법을 사용하였다. 잔여반향 및 배경잡음제거를 위해 CDMA방식의 셀룰라 이동통신에 사용되는IS-127 EVRC음성 부호화기의 표준안에 포함된 잡음제거방식을 사용하였다. 제안된 시스템을 16 비트 고정소수점DSP인 OAK DSP Core를 이용하여 약 18.6MIPS의 연산량으로 실시간 구현되었다.