• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1B
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• pp.10-15
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• 2009

Recently, there are tendency that wireless sensor network is one of the important techniques for the future IT industry and thereby application areas in it are getting growing. Researches based on the hierarchical network topology are evaluated in good at energy efficiency in related protocols for wireless sensor network. LEACH is the best well known routing protocol for the hierarchical topology. However, there are problems in the range of message broadcasting, which should be expand into the overall network coverage, in LEACH related protocols. Thereby, this paper proposes a new clustering scheme to solve the co-shared problems in them. The basic idea of our scheme is using the inherent memory restrictions in sensor nodes. The results show that the proposed scheme could support the load balancing by distributing the clusters with a reasonable number of member nodes and thereby the network life time would be extended in about 1.8 times longer than LEACH.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1082-1092
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• 2008

In wireless sensor networks, clustering protocol such as LEACH is an efficient method to increase whole networks lifetime. However, this protocol result in high energy consumption at the cluster head node. Hence, this protocol must changes the cluster formation and cluster head node in each round to prolong the network lifetime. But this method also causes a high amount of energy consumption during the set-up process of cluster formation. In order to improve energy efficiency, in this paper, we propose a new cluster formation algorithm. In this algorithm, we define a intra cluster as the sensor nodes within close proximity of each other. In a intra cluster, a node senses and transmits data at a time on the round-robin basis. In a view of whole network, intra cluster is treated as one node. During the setup phase of a round, intra clusters are formed first and then they are re-clustered(network cluster) by choosing cluster-heads(intra clusters). In the intra cluster with a cluster-head, every member node plays the role of cluster-head on the round-robin basis. Hence, we can lengthen periodic round by a factor of intra cluster size. Also, in the steady-state phase, a node in each intra cluster senses and transmits data to its cluster-head of network cluster on the round-robin basis. As a result of analysis and comparison, our scheme reduces energy consumption of nodes, and improve the efficiency of communications in sensor networks compared with current clustering methods.

• Journal of Korea Multimedia Society
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• v.25 no.11
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• pp.1564-1571
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• 2022

Wireless sensor network(WSN) is being used in various fields such as reconnaissance, echelon scale identification, weather observation, etc. using small sensors in an environment without a network infrastructure environment. In addition, WSN uses limited battery power, so study on routing protocols to extend the lifetime of the network is important. PEGASIS, a hierarchical routing protocol, accounts for the majority of energy-efficient routing protocol studies and is well known as a representative protocol. In this study, based on PEGASIS, we propose a protocol that constructs multiple chains rather than one chain using the AoA of nodes. The proposed protocol has the advantage of reducing the transmission distance of nodes and eliminating unnecessary transmissions, thereby increasing energy efficiency compared to the existing protocols.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.710-713
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• 2008

센서 네트워크는 습도, 온도, 조도 등의 다양한 정보를 수집할 수 있는 센서들을 특정한 지역이나 광범위한 지역에 분포하여 특정 이벤트를 탐지하거나 계속적으로 환경을 관찰하여 수집된 정보를 효율적으로 Base Station으로 전송하는 일종의 애드 혹 네트워크이다. 본 논문은 센서 네트워크의 라우팅 프로토콜 중 PEGASIS와 동심원 형태의 클러스터링 방법에 대해 취약점을 알아보고, 이를 해결하기 위한 방법으로 클러스터 헤드 선출을 위한 두 가지 기준을 정하고, 퍼지 이론을 기반으로 적절한 선택 값을 도출하여 효율적인 클러스터 헤드를 선출하는 방법을 제안한다. 이 방법은 각 센서 노드들의 남아있는 에너지를 고려할 수 있으며, 각 레벨에서 클러스터 헤드들은 가깝게 위치하게 되어 Multi-hop으로 데이터 전송 시 기존의 방법들보다 전송 거리를 줄일 수 있는 장점을 가지고 있다.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.141-150
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• 2005

Wireless Sensor Networks have been rapidly developed due to the advances of sensor technology and are expected to be applied to various applications in many fields. In Wireless Sensor Networks, schemes for managing the network energy-efficiently are most important. For this purpose, there have been a variety of researches to suggest routing protocols. However, existing researches have ideal assumption that all sensor nodes have sensing data to transmit. In this paper, we designed and implemented a sensing-aware cluster selection algorithm based on LEACH-C for the sensor network in which part of sensors have sensing data. We also simulated proposed algorithm on several network situation and analyzed which situation is suitable for the algorithm. By the simulation result, selecting cluster head among the sensing nodes is most energy-efficient and the result shows application of sensing-awareness in cluster head selection when not all sensors have sensing data.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.465-476
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• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. In order to alleviate the inherent vulnerability in security of the wireless sensor nodes with the hardware constraints, the lightweight security protocol is needed and a variety of research is ongoing. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring man-made objects such as bridges. This paper, furthermore, explores a two-layer authentication, key distribution scheme which distributes the key and location of a sensor node in advance, and an effective security routing protocol which can take advantage of the Sleep and Awake state. This also results in the increased data transfer rate by increasing the number of alternative routing paths and the reduced energy consumption rate.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.316-320
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• 2008

Data dissemination schemes for wireless sensor networks, where sinks and event targets might be mobile, has been one of the active research fields. For doing that, stationary nodes gathered data on behalf of mobile sinks and the relayed data in previous studies. their schemes, however, lead to frequent query flooding and report congestion problems over sink moving. We propose a data dissemination protocol to solve both the query flooding and the report congestion problem. Our scheme improves the two shortcomings through sink location management. Finally, we prove effectiveness of our protocol through computer simulations.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.56-63
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• 2012

The WBAN technology means a short distance wireless network which provides each device interactive communication by connecting devices inside and outside of body. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. Wireless body area network is usually configured in energy efficient using sensor and zigbee device due to the power limitation and the characteristics of human body. Wireless sensor network consist of sensor field and sink node. Sensor field are composed a lot of sensor node and sink node collect sensing data. Wireless sensor network has capacity of the self constitution by protocol where placed in large area without fixed position. Mobile sink node distribute energy consumption therefore network life time was increased than fixed sink node. The energy efficient is important matter in wireless body area network because energy resource was limited on sensor node. In this paper we proposed cluster topology algorithm for efficient data transmission in wireless body area network based mobile sink. The proposed algorithm show good performance under the advantage of grid routing protocol and TDMA scheduling that minimized overlap area on cluster and reduced amount of data on cluster header in error prone wireless sensor network based on mobile sink.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.10
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• pp.785-800
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• 2013

In MANET, AODV(Ad hoc On-demand Distance Vector) has its advantages as on-demand approach but it also has a disadvantage that the control packet overhead is high compared to other routing protocols. This paper improves the problem caused by Hello messages that are broadcasted periodically to detect the local connectivity and maintain neighbor list. Periodic hello messages reduce the Packet delivery ratio and the efficiency in the limited bandwidth. And its increased Control packet overhead leads to decrease the Residual battery capacity and the Network lifetime. Further, non-reactive nature of periodic hello messages in AODV has also been the source of numerous controversies. In order to solve these problems, this paper improves the performance by using the interrupt driven approach which removes periodic hello messages and decreases the Control packet overhead. Performance comparisons between the traditional AODV and proposed mod_AODV done with network simulator QualNet 5.0 show that the mod_AODV performs better in most performance metrics under scenarios with various values of simulation parameters.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.259-266
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• 2005

Recently data centric routing or application dependent routing protocols are emerged in mobile ad hoc networks. In this paper, we propose a routing method for query processing in MANET(Mobile Ad hoc NETwork) environment, called road-based query routing, with consideration on real time traffic information of large number of vehicles. In particular, we focus on the method that process arrival time dependent shortest path query in MANET without a central server on the road networks. The main idea of our approach lies in a routing message that includes query predicates based on the road connectivity and on data gathering method in real time from vehicles on the road by ad-hoc network. We unify route discovery phase and data delivery(query processing) phase in our mechanism and reduce unnecessary flooding messages by pruning mobile nodes which are not on the same or neighboring road segments. In order to evaluate the performances of the proposed method, we established a model of road networks and mobile nodes which travel along the roads. The measurement factor is the number of nodes to whom route request is propagated according to each pruning strategy. Simulation result shows that road information is a dominant factor to reduce the number of messages.