• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.760-765
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• 2007

The sensor network system which has limited resources is deployed in a wide area and plays an important role of gethering information and monitoring. Generally, fault of sensor nodes which was caused by limited resources and poor environment happens. Futhermore, this fault poses many problems related with required quality of whole network. In this paper, new fault detection algorithm which utilizes both consensus algorithm and localized faulty sensor detection scheme is proposed. To verify the feasibility of the proposed scheme, some simulation and experiment are carried out.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.386-390
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• 2007

센서 네트워크 시스템은 한정된 자원을 갖는 센서노드들을 광대한 영역에 설치하여 새로운 정보를 수집 하고 모니터링 하는 기능을 한다. 센서 노드와 센서의 고장(Sensor node faulty or Sensor faulty)은 열악한 설치 환경이나 제한된 리소스에 의해 종종 발생 되는데 이들 고장은 네트워크 내에서 요구되는 양질의 서비스 제공에 많은 문제를 가져온다. 본 논문에서는 센서 노드의 고장 검출 알고리즘으로 알려져 있는 Consensus 알고리즘과 센서노드에서 사용되는 센서의 고장을 검출할 수 있는 localized faulty sensor detection 알고리즘을 혼합하여 시스템에 안정된 서비스를 제공할 수 있는 방법을 제안하며 실제 시뮬레이션과 제작된 실험장치에 적용함으로써 그 유용성을 확인하고자 한다.

• Journal of IKEEE
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• v.20 no.4
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• pp.449-453
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• 2016

Failures would occur because of the hostile nature environment in Wireless Sensor Networks (WSNs) which is deployed randomly. Therefore, considering faults in WSNs is essential when we design WSN. This paper classified fault model in the sensor node. Especially, this paper proposed new error correcting code scheme and fault recovery algorithm in the CH(Cluster Head) node. For the range of the small size information (<16), the parity size of the proposed code scheme has the same parity length compared with the Hamming code, and it has a benefit to generate code word very simple way. This is very essential to maintain reliability in WSN with increase power efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.3965-3982
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• 2015

Event detection is one of the key issues in many wireless sensor network (WSN) applications. The uncertainties that are derived from the instability of sensor node, measurement noise and incomplete sampling would influence the performance of event detection to a large degree. Many of the present researches described the sensor readings with crisp values, which cannot adequately handle the uncertainties inhered in the imprecise sensor readings. In this paper, a fault-tolerant event detection algorithm is proposed based on Dempster-Shafer (D-S) theory (also called evidence theory). Instead of crisp values, all possible states of the event are represented by the Basic Probability Assignment (BPA) functions, with which the output of each sensor node are characterized as weighted evidences. The combination rule was subsequently applied on each sensor node to fuse the evidences gathered from the neighboring nodes to make the final decision on whether the event occurs. Simulation results show that even 20% nodes are faulty, the accuracy of the proposed algorithm is around 80% for event region detection. Moreover, 97% of the error readings have been corrected, and an improved detection capability at the boundary of the event region is gained by 75%. The proposed algorithm can enhance the detection accuracy of the event region even in high error-rate environment, which reflects good reliability and robustness. The proposed algorithm is also applicable to boundary detection as it performs well at the boundary of the event.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.147-151
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• 2005

CAN(Controller Area Network) is a simple and efficient network system for real time control and measurement. As it is not only good at error detection but also strong in electromagnetic interference, CAN has been widely used all over the industries. Basically, CAN needs a master node in charge of sensor data collection, node scheduling for data transmission to a monitoring system and error detection. According to the number of mater nodes, the CAN system is classified into two type of master system. One is a single master system that has only one master node and the other is a multi-master system where any sensor node can become a master node depending on the system's conditions. While it has the advantage of its fault tolerance, the multi-master system will suffer form the overall performance degradation when a defect is found in the master node. It is because all sensor nodes pertaining to a defective master node lose their position. Moreover, it is difficult and expensive to implement. For a single master system, the whole system will be broken down when a problem happens to a single master. In this paper, a dynamic master system is presented that there are several sub-master nodes of which basic functions are those of other sensor nodes at ordinary times but dynamically changed to replace the failing master node. An effective scheduling algorithm is also proposed to choose an appropriate node among sub-master nodes, where each sub-master node has its precedence value. The performance of the dynamic master system is experimented and analyzed.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.667-676
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• 2014

Connectivity is a crucial quality of service measure in wireless sensor networks. However, the network is always at risk of being split into several disconnected components owing to the sensor failures caused by various factors. To handle the connectivity problem, this paper introduces an in-advance mechanism to prevent network partitioning in the initial deployment phase. The approach is implemented in a distributed manner, and every node only needs to know local information of its 1-hop neighbors, which makes the approach scalable to large networks. The goal of the proposed mechanism is twofold. First, critical nodes are locally detected by the critical node detection (CND) algorithm based on the concept of maximal simplicial complex, and backups are arranged to tolerate their failures. Second, under a greedy rule, topological holes within the maximal simplicial complex as another potential risk to the network connectivity are patched step by step. Finally, we demonstrate the effectiveness of the proposed algorithm through simulation experiments.

• The KIPS Transactions:PartA
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• v.16A no.1
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• pp.17-26
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• 2009

Large-scale wireless sensor network are expected to play an increasingly important role for the data collection in harmful area. However, the physical fragility of sensor node makes reliable routing in harmful area a challenging problem. Since several sensor nodes in harmful area could be damaged all at once, the network should have the availability to recover routing from node failures in large area. Many routing protocols take accounts of failure recovery of single node but it is very hard these protocols to recover routing from large scale failures. In this paper, we propose a routing protocol, which we refer to as LSFA, to recover network fast from failures in large area. LSFA detects the failure by counting the packet loss from parent node and in case of failure detection LSFAdecreases the routing interval to notify the failure to the neighbor nodes. Our experimental results indicate clearly that LSFA could recover large area failures fast with less packets than previous protocols.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.69-74
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• 2010

Now the CAN(controller Area Network) is using electronic modules as a serial communication which is very robust to noise. Especially the CAN is using for automotive part that very popular in which automotive electronic control module, engine controller unit, sensor modules, etc. but the CAN has the order of priority to linking node and also has fault confinement so using in these features that is applied to in factory automation product line. The CAN communication is basically very robust to electric noise so varied applying to others part. In this paper, we suggest to CAN interface for embedded system that is possible for error detection using two CAN nodes on Hi-speed, full-CAN.

• Journal of IKEEE
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• v.22 no.4
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• pp.1104-1108
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• 2018

IIoT applies IoT to industrial sites to monitor factors such as production, manufacturing, and safety, and it is a solution that allows the worker to easily manage the site. An important technology element in this IIoT is a technology that collects information on industrial sites and delivers reliable information to managers using sensors. Therefore, general industrial sites use wired network methods such as Ethernet and RS485 to deliver information. However, there are limitations to the problem of infrastructure costs and to the wide range of line constructions in network deployment. Therefore, in this paper, the network of IEEE 802.15.4 Ad-Hoc wireless sensors is deployed on production lines with machine tools. In addition, we describe the routing method considering machine tool layout and sensor node failure detection algorithm.