• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.739-742
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• 2005

현재 사용되고 정보 서비스 기술의 형태는 다양화, 복잡화되고 있지만 대부분 웹 기반 서비스 기술을 사용하고 있다. 그러나 이러한 기술은 분산되어 있는 정보를 가공하는 과정이 복잡하고, 검색결과가 너무 많아 정보의 질이 저하된다. 또한, 한정적인 대역폭으로 인해 네트워크 상에 지연문제가 발생하여 효율적인 정보를 사용자에게 전달하지 못한다. 따라서 본 논문에서는 멀티 에이전트 기반의 Web/Mobile 환경에서의 능동적 정보 서비스를 위한 시스템을 구현한다. 제안된 멀티 에이전트시스템에서는 기존의 웹 기반 정보 서비스가 가진 단점들을 해결하기 위해서 이동 에이전트의 작업 실행 모듈을 분리하는 CORBA 기반의 이동에이전트를 구현하여 분산된 다양한 정보를 효과적으로 수집하였고, 네이밍 에이전트의 호스트 이주를 위해 노드의 위치 투명성 및 최초 라우팅 스케줄을 지정하는 네이밍 에이전트를 구현하였다. 마지막으로 사용자에게 지속적인 정보 서비스를 제공함으로 네트워크 트래픽을 가중시키는 문제를 해결하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.522-523
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• 2013

Delay Tolerant Network (DTN)란 노드 간 통신의 지연 시간이 길고 연결 단절이 자주 일어나는 네트워크 상황에서 데이터를 안정적으로 전달할 수 있도록 지원할 수 있는 네트워크를 말한다. DTN은 노드들 간의 연결 정도의 강약을 파악하여 연결 정도가 높은 노드를 통해 목적 노드로 메시지를 전달하는 방식을 사용한다. 노드들의 움직임이 빠르고 서로간의 거리가 멀어 지속적인 종단 간 연결성이 보장 되지 않는 상황일 때 DTN을 사용하면 안정적인 전송이 가능하다. 이때 이 노드들의 움직임을 예측 할 수 있다면 더 효과적인 메시지 전달이 가능 할 것이다. 이 논문에서는 이동 노드의 속도와 목적지 등과 같은 이동성 정보를 이용해 노드의 위치를 예측하여 효과적인 메시지 전달 경로를 결정하는 이동 예측 기반의 DTN 알고리즘을 제안한다. 이 알고리즘은 Mobility Strategy Sharing Location Service Protocol을 발전시켜 위치 정보 업데이트의 오버헤드를 최소화한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1148-1161
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• 2012

Recently, developments in the field of communication and network technologies induced new paradigm in the defense weapon system. As a consequence, military authorities develop the Tactical Information Communication Network(TICN) system to adapt to the changing paradigm. One of the most important functions of TICN is real-time communication. As a result, TICN system needs to receive real-time information from the battlefield, and the key technology to support these features is MANET(Mobile Ad-Hoc Network) routing protocol. In this paper, we analyze problems of the shortest path scheme in tactical Ad-Hoc networks, which is widely used in common Ad-Hoc networks. We propose efficient routing protocol for tactical MANET by considering the environment of small combat units, such as node position, speed and data size. The proposed algorithm shows reliable data transfer and low latency in battlefield.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.151-157
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• 2010

Rapid technological advances in the area of micro electro-mechanical systems (MEMS) have spurred the development of small inexpensive sensors capable of intelligent sensing. A significant amount of research has been done in the area of connecting large numbers of these sensors to create robust and scalable Wireless Sensor Networks (WSNs). The resource scarcity, ad-hoc deployment, and immense scale of WSNs make secure communication a particularly challenging problem. Since the primary consideration for sensor networks is energy efficiency, security schemes must balance their security features against the communication and computational overhead required to implement them. In this paper, we combine location information and probability to create a new security aware multipath geographic routing protocol. The implemented result in network simulator (ns-2) showed that our protocol has a better performance under attacks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.293-300
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• 2007

As the development of the various IP-based services, it is expected that Internet telephony service will gradually replace the traditional PSTN-based telephony service. But there are many issues resolved to spread the Internet telephony service. One of them is to support the emergency services in the Internet telephony. In the case of USA, it has been regulated that 911 services should be supported in the Internet telephony services using VoIP on the similar performance level to PSTN 911 service. According to the regulation, basic VoIP 911 calls should be routed to the general access line of LEA without the location information or the callback number, but the enhanced VoIP 911 calls with the location information and callback number should be routed on the dedicated 911 network and destined to the local 911 distribution center such as PSAP. But, in the current VoIP-based Internet telephony network, the emergency call service has not been handled as one of the special services as well at has a worse performance in comparison to it on PSTN. Moreover, the service has a critical problem that it can not be destined to the nearest PSAP because of the insufficient information about the location information and the call back number. In this paper, we suggest the SIP-based emergency call service mechanism in order to resolve the problems above mentioned. This suggested mechanism is implemented to show its effectiveness and efficiency.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.620-622
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• 2009

본 논문에서는 독거노인의 응급상황이 실내에서 발생할 경우, 집안에 사람이 없을지라도 신속히 대처할 수 있는 방안을 연구하였다. 이를 위해 USN기반의 네트워크을 설계하고, 위치인식 알고리즘과 노드간 라우팅 기술을 개발하였다. 위치인식 알고리즘으로는 RSSI방식에 의해 이동노드가 고정노드로부터 오는 전파세기를 감지하는 방식을 이용하여, 비례값을 산출하는 방식을 채택하였으며, 삼각 측량법에 의한 이동노드 위치인식 알고리즘을 적용하였다.

• Journal of KIISE
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• v.41 no.10
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• pp.810-823
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• 2014

The wireless mesh network based on IEEE 802.11s provides a routing based on a destination address as it inherits legacy internet architecture. However, this architecture interested in not 'what' which is originally the users goal but 'where'. Futhermore, because of the rapid increase of the number of mobile devices recently, the mobile traffic increases geometrically. It reduces the network effectiveness as increasing many packets which have same payload in the situation of many users access to the same contents. In this paper, we propose an OpenFlow-based contents routing for the wireless mesh network(WMN) to solve this problem. We implement contents layer to the legacy network layer which mesh network uses and the routing technique based on contents identifier for efficient contents routing. In addition we provide flexibility as we use OpenFlow. By using this, we implement caching technique to improve effectiveness of network as decreasing the packet which has same payload in WSN. We measure the network usage to compare the flooding technique, we measure the delay to compare environment using caching and non caching. As a result of delay measure it shows 20% of performance improve, and controller message decrease maximum 89%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.607-614
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• 2016

In generating station, cable spreading design is a very important task, which is very much time consuming, due to the type of cable used in generating station is very diverse. The raceway means the cable line section from source equipment to destination, and consists of cable tray and conduit. The process of existing cable spreading design was written in by hand. Thereby, there are grossly inefficient gain such as cable omission and unfixed fill value by a personal and time investment. In this paper, we proposed and implemented the automated cable route design based flexible cable fill check in generating station, and proposed the automated cable route design can be calculated the cable fill with flexible changing of raceway. Some experimental result shows that implemented cable route design is well performed and conducted as the design specifications, and it will be able to reduce the cable spreading design time.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.116-122
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• 2009

Mobile Wireless Sensor Network is an organized collection of sensor nodes and mobile sink nodes, in which the sensor node transmits the signal to the sink node. In real environment, there are many cases in which sinks have mobility caused by the people, the vehicle and etc. Since all nodes in the sensor networks have limited energy, many researches have been done in order to prolong the lifetime of the entire network. In this paper we propose Dynamic Local Update-based Routing Protocol(D-LURP) that prolong the lifetime of the entire network to efficiently maintain frequent location update of mobile sink static sensor nodes in Mobile WSNs. When the sink node moves out of the local broadcasting area the proposed D-LURP configures dynamically the local update area consisted of the new local broadcasting area and the previous dissemination node(DN) and find the path between the DN and the sink node, instead of processing a new discovering path like LURP. In this way the processing of broadcasting sink node's location information in the entire network will be omitted. and thus less energy will be consumpted. We compare the performances of the proposed scheme and existing Protocols.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.83-89
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• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.