• 융합보안논문지
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• 제12권3호
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• pp.67-73
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• 2012

본 논문에서는 지그비를 이용한 무선 기반 센서 네트워크 단점을 극복하기 위하여 유무선 네트워크 연동 기술을 이용한 하이브리드 센서 네트워크 구현 방안을 제시하였다. 제안된 유무선 연동 센서 네트워크는 CATV망에서의 저손실 전송 특성을 바탕으로 실내 무선 환경의 열악한 전송 특성을 보완할 수 있으며, 마찬가지로 동일 주파수 대역의 무선랜과 블루투스의 간섭에서도 자유로울 수 있다. 또한 이미 충분한 인프라가 구축되어 있는 CATV망을 변경없이 사용하고, 기존 무선망의 전송 부정확성에 대한 안정성과 예측 가능한 전송 링크를 제공함으로써 네트워크 설계가 보다 효율적이었으며, 센서 네트워크의 안정성과 높은 신뢰성을 보장하였다.

• 인터넷정보학회논문지
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• 제9권6호
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• pp.15-25
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• 2008

이동 에드 혹 네트워크와 센서 네트워크의 차이 때문에 이동 에드 혹 네트워크를 위한 pre-existing autoconfiguration를 센서 네트워크에 간단히 적용할 수 없다. 그러나, 아직 지역적으로 효과적인 유일한 주소 할당이 필요한 메커니즘이 있다. 본 논문은 지역적인 센서 네트워크의 하이브리드 방식의 아이디 할당 계획안을 제안한다. 이러한 하이브리드 방식은 proactive IDs assignment와 reactive IDs assignment를 결합한 방식이다. 제안된 계획안은 reactive IDs assignment을 사용하여 효율적인 통신을 고려하고, zone-based self-organized clustering with Byzantine Agreement를 사용하여 공격에 대한 안전을 고려한다. 따라서 본 논문은 네트워크 트래픽을 최소화하고 센서 네트워크의 이탈한 노드로부터 네트워크를 회복하는 문제를 해결한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권9호
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• pp.3151-3168
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• 2021

Internet of Things (IoT) connects several objects with embedded sensors and they are capable of exchanging information between devices to create a smart environment. IoT smart devices have limited resources, such as batteries, computing power, and bandwidth, but comprehensive sensing causes severe energy restrictions, lowering data quality. The main objective of the proposal is to build a hybrid protocol which provides high data quality and reduced energy consumption in IoT sensor network. The hybrid protocol gives a flexible and complete solution for sensor selection problem. It selects a subset of active sensor nodes in the network which will increase the data quality and optimize the energy consumption. Since the unused sensor nodes switch off during the sensing phase, the energy consumption is greatly reduced. The hybrid protocol uses Dijkstra's algorithm for determining the shortest path for sensing data and Ant colony inspired variable path selection algorithm for selecting active nodes in the network. The missing data due to inactive sensor nodes is reconstructed using enhanced belief propagation algorithm. The proposed hybrid method is evaluated using real sensor data and the demonstrated results show significant improvement in energy consumption, data utility and data reconstruction rate compared to other existing methods.

• 한국IT서비스학회지
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• 제8권3호
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• pp.171-184
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• 2009

Since the development of the Distributed Hash Tables (DHTs), the distributed lookup services are one of the hot topics in the networking area. The main reason of this popularity is the simplicity of the lookup structure. However, the simple key based search mechanism makes the so called "keyword" based search difficult if not impossible. Thus, the applicability of the DHTs is limited to certain areas. In this paper. we find that DHTs can be used as the ubiquitous sensor network (USN) metadata lookup service across a large number of sensor networks. The popularity of the Ubiquitous Sensor Network has motivated the development of the USN middleware services for the sensor networks. One of the key functionalities of the USN middleware service is the lookup of the USN metadata, by which users get various information about the sensor network such as the type of the sensor networks and/or nodes, the residual of the batteries, the type of the sensor nodes. Traditional distributed hash table based lookup systems are good for one sensor network. However, as the number of sensor network increases, the need to integrate the lookup services of many autonomous sensor networks so that they can provide the users an integrated view of the entire sensor network. In this paper, we provide a hybrid lookup model, in which the autonomous lookup services are combined together and provide seamless services across the boundary of a single lookup services. We show that the hybrid model can provide far better lookup performance than a single lookup system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권4호
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• pp.1224-1248
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• 2022

In various sensor network applications, such as climate observation organizations, sensor nodes need to collect information from time to time and pass it on to the recipient of information through multiple bounces. According to field tests, this information corresponds to most of the energy use of the sensor hub. Decreasing the measurement of information transmission in sensor networks becomes an important issue.Compression sensing (CS) can reduce the amount of information delivered to the network and reduce traffic load. However, the total number of classification of information delivered using pure CS is still enormous. The hybrid technique for utilizing CS was proposed to diminish the quantity of transmissions in sensor networks.Further the energy productivity is a test task for the sensor nodes. However, in previous studies, a clustering approach using hybrid CS for a sensor network and an explanatory model was used to investigate the relationship between beam size and number of transmissions of hybrid CS technology. It uses efficient data integration techniques for large networks, but leads to clone attacks or attacks. Here, a new algorithm called SBEA (Snowball Endurance Algorithm) was proposed and tested with a bow. Thus, you can extend the battery life of your WSN by running effective copy detection. Often, multiple nodes, called observers, are selected to verify the reliability of the nodes within the network. Personal data from the source centre (e.g. personality and geographical data) is provided to the observer at the optional witness stage. The trust and reputation system is used to find the reliability of data aggregation across the cluster head and cluster nodes. It is also possible to obtain a mechanism to perform sleep and standby procedures to improve the life of the sensor node. The sniffers have been implemented to monitor the energy of the sensor nodes periodically in the sink. The proposed algorithm SBEA (Snowball Endurance Algorithm) is a combination of ERCD protocol and a combined mobility and routing algorithm that can identify the cluster head and adjacent cluster head nodes.This algorithm is used to yield the network life time and the performance of the sensor nodes can be increased.

• 대한안전경영과학회지
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• 제14권1호
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• pp.137-145
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• 2012

In the previous study, the construction guide line of IT infra-structure for a u-City was introduced. However, it is only concentrated on the components and construction procedure for provider-oriented and technology-oriented sensor networks. In this paper the architecture and building process of demander-oriented sensor networks for sustainable u-City service are proposed. In the paper it is described (1) the enhancement methods of the procedure that can be flexibly constructed according to the scale of the project, (2) the methods that can improve the structure from the wireless sensor network such as RFID/USN to the hybrid sensor network, and (3) the consideration factors for providing the sustainable u-City service.

• 대한토목학회논문집
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• 제26권4A호
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• pp.639-645
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• 2006

FRP(Fiber Reinforced Polymer)는 부식의 저항성, 고강도, 피로저항 능력 및 성형성 등에서 우수한 건설 신소재이다. 광섬유 브래그 격자(Fiber Bragg Grating; FBG) 센서는 전자기 저항, 작은 소재의 크기, 그리고 높은 내구성 등의 이점으로 smart sensor로서 현재 많이 사용되고 있다. 하지만 FBG 센서의 변위 측정 기술 능력의 부족으로 현재까지는 변형률, 온도 등의 물리량 측정센서로서 활용되고 있는 실정이다. 본 연구에서는 FRP와 FBG센서의 기능 복합화(Hybrid)를 통하여 smart FRP Rod를 개발 한 후 인장시험을 실시하였다. 또한, FBG센서에 의해 측정된 변형률 데이터를 신경망(Neural Network) 기법을 이용하여 변위 추정 모형을 개발함으로서 FBG 센서 단점인 변형률 계측만을 위한 센싱 역할을 극복하고자 한다. 인공신경망 모형은 MLP(Multi-layer Perceptron)로, 오차범위 0.001에 수렴 될 수 있도록 학습(training)을 실시하였다. 학습에는 비선형 목적함수와 역전파 학습(Back-propagation) 알고리즘을 적용하였으며 모형의 검증은 UTM에서 측정된 변위 값과 수치해석에 의한 결과 값을 비교함으로서 실시하였다.

• ETRI Journal
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• 제39권2호
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• pp.222-233
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• 2017

Debugging in distributed environments, such as wireless sensor networks (WSNs), which consist of sensor nodes with limited resources, is an iterative and occasionally laborious process for programmers. In sensor networks, it is not easy to find unintended bugs that arise during development and deployment, and that are due to a lack of visibility into the nodes and a dearth of effective debugging tools. Most sensor network debugging tools are not provided with effective facilities such as real-time tracing, remote debugging, or a GUI environment. In this paper, we present a hybrid debugging framework (HDF) that works on WSNs. This framework supports query-based monitoring and real-time tracing on sensor nodes. The monitoring supports commands to manage/control the deployed nodes, and provides new debug commands. To do so, we devised a debugging device called a Docking Debug-Box (D2-Box), and two program agents. In addition, we provide a scalable node monitor to enable all deployed nodes for viewing. To transmit and collect their data or information reliably, all nodes are connected using a scalable node monitor applied through the Internet. Therefore, the suggested framework in theory does not increase the network traffic for debugging on WSNs, and the traffic complexity is nearly O(1).

• Journal of information and communication convergence engineering
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• 제8권5호
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• pp.549-553
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• 2010

Lim et al. proposed a Hybrid Group Key Management scheme for Hierarchical Self-Organizing Sensor Network in 2008 to provide a secure way to pass down the group key for cluster-based communication. This paper presents two practical attacks on the scheme proposed by Lim et al. by tampering sensor nodes of a cluster to recover necessary secret keys and by exploiting the IDS employed by the scheme. The first attack enables a long-term but slow data fabrication while other attack causes more severe DoS on the access to cluster sensor nodes.

• 한국컴퓨터정보학회논문지
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• 제13권2호
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• pp.177-183
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• 2008

본 논문에서는 무선센서 네트워크에서 네트워크 성능을 향상시키는 하이브리드 MAC 프로토콜을 제안한다. 제안된 MAC 프로토콜 구조는 많은 노드들로 구성된 무선센서 네트워크를 위해 특별히 설계되었다. 본 논문에서 기여한 점은 다음과 같다. 먼저, 제안된 스케줄링 알고리즘은 네트워크 토폴로지에 무관하게 동작한다 BS의 원 홉(one hop) 노드 수가 증가하는 밀도가 높은 네트워크 환경에서도 주파수의 추가 사용 없이 모든 타임 슬롯을 사용 할 수 있다. 둘째로, BS의 one hop 노드는 필요에 따라 하나 이상의 타임 슬롯을 사용할 수 있기 때문에 네트워크 성능이 향상된다. 본 논문에서 제안된 구조와 기존의 연구인 HyMAC[1]과의 네트워크 성능 비교를 하였다.