• Journal of the Korea Society for Simulation
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• v.23 no.2
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• pp.65-72
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• 2014

Sensor nodes are easily compromised by attacker when which are divided in open environment. The attacker may inject false report and false vote attack through compromised sensor node. These attacks interrupt to transmission legitimate report or the energy of sensor node is exhausted. PVFS are proposed by Li and Wu for countermeasure in two attacks. The scheme use inefficiency to energy of sensor node as fixed report threshold and verification node. In this paper, our propose the next neighbor node selection scheme based on fuzzy logic system for energy improvement of PVFS. The parameter of fuzzy logic system are energy, hops, verification success count, CH select high the next neighbor node among neighbor nodes of two as deduction based on fuzzy logic system. In the experimental, our proposed scheme was improvement to energy of about 9% compare to PVFS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1200-1209
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• 2011

In this paper, we propose a novel energy efficient MAC protocol which is based on orthogonal frequency division multiple access (OFDMA) and exploits the physical characteristic that propagation loss of acoustic wave depends on the distance. In the proposed scheme, sensor nodes are grouped according to the distance to sink node. Then, each group uses a different frequency band. The proposed scheme not only enables all sensor nodes to maintain the signal-to-noise ratio above a certain required level (Accepted Minimum SNR, AMS), but also reduces overall transmission power consumption. In addition, the dynamic sub-channel allocation is employed in order to improve data transmission rate. Simulations show that proposed MAC protocol has better performance in a delay-tolerant underwater acoustic sensor networks.

• Journal of KIISE:Databases
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• v.37 no.3
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• pp.137-145
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• 2010

Wireless sensors play important roles in various areas as ubiquitous computing is generalized. Depending on applications properties, each sensor can be equipped with limited computing power in addition to general function of gathering environment-related information. One of main issues in this environment is to improve energy-efficiency in sensor nodes. In this paper, we devise a new attribute-query processing algorithm. Each sensor has to maintain partial information locally about attributes values gathered at its all descendent nodes. As the volume is higher, however, the maintenance cost also increases. And the update cost also has to be considered in the proposed algorithm. Thus, some bits, AVB(Attribute-Value Bits), are delivered instead of the value itself, where each bit represents a bound of attribute. Thus, the partial information can decrease the number of exchanged messages with a little cost during query processing. Through simulation works, the proposed algorithm is analyzed from several points of view.

• Journal of KIISE:Databases
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• v.33 no.2
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• pp.188-200
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• 2006

Once a continuous query, which is commonly used in sensor networks, is issued, the query is executed many times with a certain interval and the results of those query executions are collected to the base station. Since this comes many communication messages continuously, it is important to reduce communication cost for collecting data to the base station. In sensor networks, in-network processing reduces the number of message transmissions by partially aggregating results of an aggregate query in intermediate nodes, or merging the results in one message, resulting in reduction of communication cost. In this paper, we propose a routing tree for sensor nodes that qualify the given query predicate, called the query specific routing tree(QSRT). The idea of the QSRT is to maximize in-network processing opportunity. A QSRT is created seperately for each query during dissemination of the query. It is constructed in such a way that during the collection of query results partial aggregation and packet merging of intermediate results can be fully utilized. Our experimental results show that our proposed method can reduce message transmissions more than 18% compared to the existing one.

• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.31-36
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• 2008

The clock frequency difference of sensor nodes is one of main parameters in TOF estimation and affect to degrade ranging algorithms to estimate positions of mobile nodes in wireless sensor networks. The specification of IEEE802.15.4a describes asynchronous TWR and SDS-TWR insensitive to frequency difference without any additional network synchronization. But the TWR and SDS-TWR can not eliminate sufficiently the effect of frequency difference of node pair, packet processing delay and its difference. Especially use of low cost oscillator with wide range offset, sensor node with different hardware and software can make the positioning errors worse. We propose an estimation method of frequency differences, and apply the measured frequency differences to TWR and SDS-TWR. We evaluate the performance of the proposed algorithm with simulation, and make certain that the proposed method enhances the performance of existing algorithms with positioning errors less than 25 cm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.596-603
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• 2019

A reprogramming operation is necessary to update the software code of the node to change or update the functionality of the deployed node in wireless sensor networks. This paper proposes an optimization algorithm that minimizes the transmission energy of a node for the purpose of reprogramming a node in wireless sensor networks. We also design an algorithm that keeps energy consumption of all nodes balanced in order to maintain the lifetime of the network. In this paper, we propose a Tabu search algorithm with a new neighborhood generation method for minimizing transmission energy and energy consumption in wireless sensor networks with many nodes. The proposed algorithm is designed to obtain optimal results within a reasonable execution time. The performance of the proposed Tabu search algorithm was evaluated in terms of the node's transmission energy, remaining energy, and algorithm execution time. The performance evaluation results showed better performance than the previous methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.113-119
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• 2020

Large sensor networks require the collection and analysis of data from a large number of sensors. The number of sensors that can be controlled per micro controller is limited. In this paper, we propose how to aggregate sensor data from a large number of sensors using a large number of microcontrollers and multiple bridge nodes, and design and implement an efficient communication system for sensor data collection. Bridge nodes aggregate data from multiple microcontrollers using SPI communication, and transfer the aggregated data to PC servers using wireless TCP/IP communication. In this paper, the communication system was constructed using the Open H/W Aduo Mini and ESP8266 and performance of the system was analyzed. The performance analysis results showed that more than 30 sensing data can be collected per second from more than 700 sensors.

• The Journal of the Acoustical Society of Korea
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• v.28 no.8
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• pp.774-780
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• 2009

This paper proposes a transmitted power saving method for underwater acoustic sensors considering the acoustic wave propagation characteristic that propagation loss increases more rapidly in higher frequency band. In the proposed scheme, sensor nodes are divided into a few groups based on the distance between sink node and the sensor node, and each group uses its own frequency band. The node group with longer distance uses lower frequency and the node group with shorter distance uses higher frequency. By means of such a distance-dependent frequency allocation, all sensor nodes are able to maintain a certain target signal-to-noise ratio (SNR), but also save transmitted power. In addition, the optimum size of node group is obtained, and also a frequency allocation algorithm is proposed accordingly. Numerical results show that the proposed scheme saves transmitted power by more 10 dB comparing non-grouping methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.8
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• pp.2214-2229
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• 2024

Wireless sensor network (WSN) consists of large number of sensor nodes that are deployed in geographical locations to collect sensed information, process data and communicate it to the control station for further processing. Due the unfriendly environment where the sensors are deployed, there exist many possibilities of malicious nodes which performs malicious activities in the network. Therefore, the security threats affect performance and life time of sensor networks, whereas various security aspects are there to address security issues in WSN namely Cryptography, Trust Management, Intrusion Detection System (IDS) and Intrusion Prevention Systems (IPS). However, IDS detect the malicious activities and produce an alarm. These malicious activities exploit vulnerabilities in the network layer and affect all layers in the network. Existing feature selection methods such as filter-based methods are not considering the redundancy of the selected features and wrapper method has high risk of overfitting the classification of intrusion. Due to overfitting, the classification algorithm fails to detect the intrusion in better manner. The main objective of this paper is to provide the efficient feature selection algorithm which was suitable for any type classification algorithm to detect the intrusion in an effective manner. This paper, the security of the network is addressed by proposing Feature Selection Algorithm using Chi Squared with Ensemble Method (FSChE). The proposed scheme employs the combination of decision tree along with the random forest classification algorithm to form ensemble classifier. The experimental results justify the feasibility of the proposed scheme in terms of attack detection, packet delivery ratio and time analysis by employing NSL KDD cup data Set. The obtained results shows that the proposed ensemble method increases the overall performance by 10% to 25% with respect to mentioned parameters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1935-1940
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• 2009

One of the key technical challenges of wireless sensor network (WSN) is location management of sensor nodes. Typical node location management methods use GPS, ultrasonic sensors or RSSI. In this paper we propose a new location management method which adopts regression analysis of RSSI measurement to improve the accuracy of sensor node position estimation. We also evaluated the performance of proposed method by comparing the experimental results with existing scheme. According to the results, our proposed method, LM-RAR, shows better accuracy than existing location management scheme using RSSI and Friis' equation.