• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.778-786
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• 2012

Sensors that are used on wireless sensor networks can be divided into two types: directional sensors, such as PIR, image, and electromagnetic sensors; and non-directional sensors, such as seismic, acoustic and magnetic sensors. In order to guarantee the line-of-sight of a directional sensor, the installation location of the sensor must be higher than ground level. Among non-directional sensors, seismic sensors should be installed on the ground in order to ensure the maximal performance. As a result, seismic sensors may have network connectivity problems due to communication failure. In this paper, we propose a 3D node deployment method to maximize the coverage and the network connectivity considering the sensor-specific properties. The proposed method is for non-directional sensors to be placed on the ground, while the directional sensor is installed above the ground, using trees or poles, to maximize the coverage. As a result, through the topology that the detection data from non-directional sensors are transmitted to the directional sensor, we can maximize the network connectivity. Simulation results show that our strategy improves sensor coverage and network connectivity.

• Electronics and Telecommunications Trends
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• v.38 no.2
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• pp.36-45
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• 2023

Segment routing (SR) is a source-based routing architecture in which a node steers packets adhering to service and topological requirements. Using programmable segments, SR enables end-to-end service connectivity to satisfy the network constraints of various services. SR can be implemented with both MPLS and IPv6 dataplanes. This survey presents the overview of SR for IPv6 dataplane (SRv6), network programming technologies based on SRv6, and the SR deployment status.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2178-2181
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• 2003

Active networks allow active node’s functionality to be extended dynamically through the use of active extensions. This flexible architecture facilitates the deployment of new network protocols and services. However, the active nature of a network also raises serious safety and security concerns. These concerns must be addressed before active networks can be deployed. In this paper we look at how we can control active extension’s access to different active nodes. Specifically, the authentication between active nodes is very important in this case. We use unique identity each node has for transferring access policies between active nodes. In this paper, we suggest a new method of transferring access policies performing authentications using identities between active nodes.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.219-220
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• 2009

Many surveillance cameras used in security system are controlled with RS-485 communication protocol. In this situation, if RS-485 connection can be replaced with wireless connection using sensor network technology, an installation will become ease because of no wired connection and also a deployment of cameras will become free. This paper explains about the design of wireless sensor node and the necessary implementation for an operation, which can be replacing RS-485 connection for the development of CCTV control system based on wireless sensor network. The hardware platform of sensor node was designed based on MicaZ and the software was developed based on TinyOS. To control surveillance cameras deployed on wide area, the supporting of multi-hop also was implemented. With the result of experiment deploying on real environment, it was revealed that the controller could control cameras quickly with wireless.

• Journal of information and communication convergence engineering
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• v.16 no.1
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• pp.6-11
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• 2018

It is important to find the random estimation points in wireless sensor network. A link quality indicator (LQI) is part of a network management service that is suitable for a ZigBee network and can be used for localization. The current quality of the received signal is referred as LQI. It is a technique to demodulate the received signal by accumulating the magnitude of the error between ideal constellations and the received signal. This proposed model accepts any number of random estimation point in the network and calculated its nearest anchor centroid node pair. Coordinates of the LQI sphere are calculated from the pair and are added iteratively to the initially estimated point. With the help of the LQI and weighted centroid localization, the proposed system finds the position of target node more accurately than the existing system by solving the problems related to higher error in terms of the distance and the deployment of nodes.

• Journal of Information Processing Systems
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• v.9 no.3
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• pp.477-488
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• 2013

Wireless Sensor Networks (WSNs) are comprised of sensor nodes that forward data in the shape of packets inside a network. Proficient packet forwarding is a prerequisite in sensor networks since many tasks in the network, together with redundancy evaluation and localization, depend upon the methods of packet forwarding. With the motivation to develop a fault tolerant packet forwarding scheme a Self-Localized Packet Forwarding Algorithm (SLPFA) to control redundancy in WSNs is proposed in this paper. The proposed algorithm infuses the aspects of the gossip protocol for forwarding packets and the end to end performance of the proposed algorithm is evaluated for different values of node densities in the same deployment area by means of simulations.

• 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.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.571-578
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• 1998

In this paper, we deal with a node weighted Steiner Ring Problem (SRP) arising from the deployment of Synchronous Optical Networks (SONET), a standard of transmission using optical fiber technology. The problem is to find a minimum weight cycle (ring) covering a subset of nodes in the network considering node and link weights. We have developed two mathematical models, one of which is stronger than the other in terms of LP bounds, whereas the number of constraints of the weaker one is polynomially bounded. In order to solve the problem optimally, we have developed some preprocessing rules and valid inequalities. We have also prescribed an effective heuristic procedure for providing tight upper bounds. Computational results show that the stronger model is better in terms of computation time, and valid inequalities and preprocessing rules are effective for solving the problem optimally.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.412-414
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• 2005

Because a sensor node must operate on a tiny battery, the goal to eliminate energy inefficiencies leads the current researchers excavating for new techniques to advocate. As sensor networks edge closer towards wide spread deployment, security issues become a central concern. So far much research has focused on making sensor networks feasible and useful, and has not concentrated much on security issues especially computationally inexpensive techniques. In this paper we introduce a simple scheme relying on one-way hash-functions that greatly enhances location privacy by changing traceable identifiers on every read getting by with only a single, unreliable message exchange. Thereby the scheme is safe from many threats like eavesdropping, message interception, spoofing, and replay attacks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.646-648
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• 2010

A Sensor Node in Wireless Sensor Network has very limited resources such as processing capability, memory capacity, battery power, and communication capability. When the communication between any two sensor nodes are required to be secured, the symmetric key cryptography technique is used for its advantage over public key cryptography in terms of requirement of less resources. Keys are pre-distributed to each sensor node from a set of keys called key pool before deployment of sensors nodes. Combinatorial design helps in a great way to determine the way keys are drawn from the key pool for distributing to individual sensor nodes. We study various deterministic key predistribution techniques that are based on combinatorial design.