• 한국인터넷방송통신학회논문지
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• 제15권4호
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• pp.63-70
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• 2015

유비쿼터스 시대의 도래와 함께 센서를 기반으로 하는 무선 센서 네트워크의 응용 분야는 광범위하게 확산되고 있다. 따라서 무선 센서 네트워크에서 센서들로부터 수집되는 기밀 데이터를 허가 받지 않은 사용자로부터 보호하기 위해, 널리 사용되어지는 스마트카드와 패스워드 기반의 사용자 인증도 견고한 보안을 요구한다. 최근 무선 센서 네트워크는 클러스터 헤드와 센서 노드 이원화를 통해 운용상 보다 효과적인 계층적 무선 센서 네트워크로 전개 발전되고 있다. 2012년 Das 등은 계층적 무선 센서 네트워크에 실제 적용 가능한 동적 패스워드 기반 사용자 인증 스킴을 제안하였다. 본 논문은 안정성 분석을 통해 Das 등의 스킴이 그들의 주장과 달리 여전히 중간자 공격, 패스워드 추측 공격, 패스워드 변경 공격을 막을 수 없을 뿐 아니라, 필수적인 보안 요구사항인 사용자와 클러스터 헤드 간의 상호인증을 투명하게 제공하지 못함을 입증한다.

• Journal of information and communication convergence engineering
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• 제8권2호
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• pp.212-218
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• 2010

In wireless sensor networks (WSNs), both efficient energy management and Quality of Service (QoS) are important issues for some applications. For creating robust networks, real-time services are usually employed to satisfy the QoS requirements. In this paper, we proposed a hierarchical real-time MAC (medium access control) protocol for (m,k)-firm constraint in wireless sensor networks shortly called HRTS-MAC. The proposed HRTS-MAC protocol is based on a dynamic priority assignment by (m,k)-firm constraint. In a tree structure topology, the scheduling algorithm assigns uniform transmitting opportunities to each node. The paper also provides experimental results and comparison of the proposed protocol with E_DBP scheduling algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3468-3495
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• 2015

In this paper, we present a multi-chain based hierarchical topology control algorithm (MCHTC) for wireless sensor networks. In this algorithm, the topology control process using static clustering is divided into sensing layer that is composed by sensor nodes and multi-hop data forwarding layer that is composed by leader nodes. The communication cost and residual energy of nodes are considered to organize nodes into a chain in each cluster, and leader nodes form a tree topology. Leader nodes are elected based on the residual energy and distance between themselves and the base station. Analysis and simulation results show that MCHTC outperforms LEACH, PEGASIS and IEEPB in terms of network lifetime, energy consumption and network energy balance.

• 한국신뢰성학회지:신뢰성응용연구
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• 제5권4호
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• pp.465-486
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• 2005

A unreliable network system results in unsatisfied performance. A performance criterion of a network is throughput and availability. One of the most compelling technological advances of this decade has been the advent of deploying wireless networks of heterogeneous smart sensor nodes for complex information gathering tasks, The advancement and popularization of wireless communication technologies make more efficiency to network devices with wireless technology than with wired technology. Recently, the research of wireless sensor network has been drawing much attentions. In this paper, We evaluate throughput and availability of wireless sensor network, which have hierarchical structure based on clustering and estimate the maximum hroughput, average throughput and availability of the network considering several link failure patterns likely to happen at a cluster consisted of sensor nodes. Also increasing a number of sensor nodes in a cluster, We analysis the average throughput and availability of the network.

• Journal of Communications and Networks
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• 제17권5호
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• pp.473-481
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• 2015

In this study, we propose a clustering algorithm to enhance the performance of wireless sensor and actuator networks (WSANs). In each cluster, a multi-level hierarchical structure can be applied to reduce energy consumption. In addition to the cluster head, some nodes can be selected as intermediate nodes (INs). Each IN manages a subcluster that includes its neighbors. INs aggregate data from members in its subcluster, then send them to the cluster head. The selection of intermediate nodes aiming to optimize energy consumption can be considered high computational complexity mixed-integer linear programming. Therefore, a heuristic lowest energy path searching algorithm is proposed to reduce computational time. Moreover, a channel assignment scheme for subclusters is proposed to minimize interference between neighboring subclusters, thereby increasing aggregated throughput. Simulation results confirm that the proposed scheme can prolong network lifetime in WSANs.

• 한국통신학회논문지
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• 제33권1B호
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• pp.48-57
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• 2008

센서 네트워크는 수많은 센서 노드로 구성되어 있으며, 주변 환경을 감시하는 용도로 사용된다. 현재까지 수행되어 온 센서 네트워크에 대한 연구는 대부분 고정된 상태의 싱크 노드를 고려하고 있기 때문에, 싱크 노드의 이동성을 바탕으로 한 유비쿼터스 응용에서는 센서 필드에서 수집된 데이터가 이동 싱크 노드가지 끊김없이 전송되는데 어려움이 존재한다. 센서 데이터가 손실되지 않고 이동 싱크 노드에 전달되기 위해서는 라우팅 경로가 싱크 노드의 이동에 따라 갱신되어야 하는데, 본 논문에서는 센서 네트워크의 계층적 멀티 홉 라우팅 프로토콜에서 이동 싱크 노드로 향한 라우팅 경로가 손실되지 않고 계속해서 갱신되도록 하는 방안을 제안한다. 컴퓨터 시뮬레이션을 통해 제안한 방안의 우수성을 검증하였으며, 위치 기반 라우팅 프로토콜을 사용하여 이동 싱크 노드로 향한 경로를 갱신하는 기존 방법과 성능을 비교하여 제안된 방안이 기존 방안 보다 우수함을 보였다.

• 전기전자학회논문지
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• 제11권4호
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• pp.322-330
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• 2007

Recent advances in wireless networks and low-cost, low-power design have led to active research in large-scale networks of small, wireless, low power sensors and actuators, In large-scale networks, lots of timing-synchronization protocols already exist (such as NTP, GPS), In ad-hoc networks, especially wireless sensor networks, it is hard to synchronize all nodes in networks because it has no infrastructure. In addition, sensor nodes have low-power CPU (it cannot perform the complex computation), low batteries, and even they have to have active and inactive section by periods. Therefore, new approach to time synchronization is needed for wireless sensor networks, In this paper, I propose Energy-Efficient Time Synchronization (EETS) protocol providing network-wide time synchronization in wireless sensor networks, The algorithm is organized two phase, In first phase, I make a hierarchical tree with sensor nodes by broadcasting "Level Discovery" packet. In second phase, I synchronize them by exchanging time stamp packets, And I also consider send time, access time and propagation time. I have shown the performance of EETS comparing Timing-sync Protocol for Sensor Networks (TPSN) and Reference Broadcast Synchronization (RBS) about energy efficiency and time synchronization accuracy using NESLsim.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.224-242
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• 2010

Data routing in wireless sensor networks must be energy-efficient because tiny sensor nodes have limited power. A cluster-based hierarchical routing is known to be more efficient than a flat routing because only cluster-heads communicate with a sink node. Existing hierarchical routings, however, assume unrealistically large radio transmission ranges for sensor nodes so they cannot be employed in real environments. In this paper, by considering the practical transmission ranges of the sensor nodes, we propose a clustering and routing method for hierarchical sensor networks: First, we provide the optimal ratio of cluster-heads for the clustering. Second, we propose a d-hop clustering scheme. It expands the range of clusters to d-hops calculated by the ratio of cluster-heads. Third, we present an intra-cluster routing in which sensor nodes reach their cluster-heads within d-hops. Finally, an inter-clustering routing is presented to route data from cluster-heads to a sink node using multiple hops because cluster-heads cannot communicate with a sink node directly. The efficiency of the proposed clustering and routing method is validated through extensive simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2732-2753
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• 2019

With the application of wireless sensor networks in the fields of ecological observation, defense military, architecture and urban management etc., the security problem is becoming more and more serious. Characteristics and constraint conditions of wireless sensor networks such as computing power, storage space and battery have brought huge challenges to protection research. Inspired by the danger theory in biological immune system, this paper proposes an intrusion detection model for wireless sensor networks. The model abstracts expressions of antigens and antibodies in wireless sensor networks, defines meanings and functions of danger signals and danger areas, and expounds the process of intrusion detection based on the danger theory. The model realizes the distributed deployment, and there is no need to arrange an instance at each sensor node. In addition, sensor nodes trigger danger signals according to their own environmental information, and do not need to communicate with other nodes, which saves resources. When danger is perceived, the model acquires the global knowledge through node cooperation, and can perform more accurate real-time intrusion detection. In this paper, the performance of the model is analyzed including complexity and efficiency, and experimental results show that the model has good detection performance and reduces energy consumption.

• 한국통신학회논문지
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• 제34권12B호
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• pp.1514-1523
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• 2009

현재 무선 센서 네트워크의 주소 할당 기법들은 수백 개 이상의 노드로 구성된 대규모 센서 네트워크를 지원함에 있어 한계를 갖고 있다. WSNs 관련 대표적인 표준화 단체인 ZigBee Alliance에서는 균형 트리 기반의 주소 영역을 구성한 후, 트리 구조에 맞추어 네트워크의 주소를 할당하는 분산 주소 할당 기법이 제시되었다. 하지만 일반적으로 실제 배치된 네트워크는 균형 트리 구조를 갖지 않으며 이로 인해 주소의 낭비 및 고갈이 발생한다. 본 논문에서는 이러한 단점을 해결하기 위해 다수의 균형 트리를 동적으로 구성하는 계층적 클러스터 트리 기반 분산 주소 할당 기법을 제시한다. 제안된 방안에서는 16-bit 주소 영역을 클러스터 식별자 영역과 클러스터 내 주소 영역으로 구분하여 각 클러스터 내부에서는 균형 트리 기반 분산 주소 할당 기법을 사용하고, 주소 고갈 발생시에는 동적으로 새로운 클러스터를 형성하여 주소를 할당한다. 시뮬레이션을 통한 성능 분석에서는 제안된 프로토콜이 기존의 기법보다 주소 사용의 효율 및 고아 노드 발생 부분에서 향상된 결과를 보여준다.