• ETRI Journal
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• v.42 no.3
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• pp.341-350
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• 2020

In a wireless sensor network (WSN), the data transmission technique based on the cooperative multiple-input multiple-output (CMIMO) scheme reduces the energy consumption of sensor nodes quite effectively by utilizing the space-time block coding scheme. However, in networks with high node density, the scheme is ineffective due to the high degree of correlated data. Therefore, to enhance the energy efficiency in high node density WSNs, we implemented the distributed source coding (DSC) with the virtual multiple-input multiple-output (MIMO) data transmission technique in the WSNs. The DSC-MIMO first compresses redundant source data using the DSC and then sends it to a virtual MIMO link. The results reveal that, in the DSC-MIMO scheme, energy consumption is lower than that in the CMIMO technique; it is also lower in the DSC single-input single-output (SISO) scheme, compared to that in the SISO technique at various code rates, compression rates, and training overhead factors. The results also indicate that the energy consumption per bit is directly proportional to the velocity and training overhead factor in all the energy saving schemes.

• Convergence Security Journal
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• v.16 no.5
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• pp.3-9
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• 2016

The wireless sensor networks have become an economically viable monitoring solution for a wide variety of civilian and military applications. The main challenge in wireless sensor networks is the secure transmission of information through the network, which ensures that the network is secure, energy-efficient and able to identify and prevent intrusions in a hostile or unattended environment. In that correspondence, this paper proposes a distributed clustering process that integrates the necessary measures for secure wireless sensors to ensure integrity, authenticity and confidentiality of the aggregated data. We use the notion of pre-distribution of symmetric and asymmetric keys for a secured key management scheme, and then describe the detailed scheme which each sensor node within its cluster makes use of the pre-distribution of cryptographic parameters before deployment. Finally, we present simulation results for the proposed scheme in wireless sensor network.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.74-80
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• 2007

Advances in electronic and computer technologies have paved the way for the proliferation of WSN(wireless sensor networks). Accordingly, necessity of anti-collusion and authentication technology is increasing on the sensor network system. Some of the algorithm developed for the anti-collision sensor network can be easily adopted to wireless sensor network platforms and in the same time they can meet the requirements for sensor networks like: simple parallel distributed computation, distributed storage, data robustness and auto-classification of sensor readings. To achieve security in wireless sensor networks, it is important to be able to establish safely channel among sensor nodes. In this paper, we proposed the USN(Ubiquitous Sensor Network) channel establishment algorithm for sensor's authentication and anti-collision. Two different data aggregation architectures will be presented, with algorithms which use wavelet filter to establish channels among sensor nodes and BIBD (Balanced Incomplete Block Design) which use anti-collision methods of the sensors. As a result, the proposed algorithm based on BIBD and wavelet filter was made for 98% collision detection rate on the ideal environment.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.605-606
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• 2012

In this paper, we consider the problem of scheduling sensor activity to prolong the network lifetime while guaranteeing both discrete target coverage and connectivity among all the active sensors and the sink, called connected target coverage (CTC) problem. We proposed a distributed scheme called Distributed Lifetime-Maximizing Scheme (DLMS) to solve the CTC problem. Our proposed scheme significantly reduces the cost of the construction of the connected cover graphs in comparison with the some conventional schemes. In addition, the energy consumption is more balanced so that the network lifetime will be increased. Our simulation results show that DLMS scheme performs much better than the conventional schemes in terms of the network lifetime.

• ETRI Journal
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• v.39 no.2
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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).

• KSCI Review
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• v.14 no.2
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• pp.199-204
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• 2006

The sensor network is a wireless network of the sensor nodes which sensing, computation and communication ability. Each sensor nodes create the data items by sensor nodes above one. Like this feature, the sensor network is similar to distributed data base system. The sensor node of the sensor network is restricted from the power and the memory resources is the biggest weak point and is becoming the important research object. In this paper, We try to see efficient sensor data stream management method and efficient query processing method under the restricted sensor network environment.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.525-534
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• 2005

We present several distributed algorithms for localizing nodes of a wireless sensor network. Our algorithms determine locations of nodes based on the connectivity between nodes. The basic idea behind our algorithms is to estimate distances between nearby nodes by counting their common neighbors. We analyze the performance of our algorithms experimentally. The results of experiments show that our algorithms achieve performance improvements upon the existing algorithms

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4774-4796
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• 2018

Wireless sensor networks are composed of a large number of inexpensive and tiny sensors used in different areas including military, industry, agriculture, space, and environment. Fault tolerance, which is considered a challenging task in these networks, is defined as the ability of the system to offer an appropriate level of functionality in the event of failures. The present study proposed an intelligent throughput descent and distributed energy-efficient mechanism in order to improve fault tolerance of the system against soft and permanent faults. This mechanism includes determining the intelligent neighborhood radius threshold, the intelligent neighborhood nodes number threshold, customizing the base paper algorithm for distributed systems, redefining the base paper scenarios for failure detection procedure to predict network behavior when running into soft and permanent faults, and some cases have been described for handling failure exception procedures. The experimental results from simulation indicate that the proposed mechanism was able to improve network throughput, fault detection accuracy, reliability, and network lifetime with respect to the base paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.50-58
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• 2013

In Wireless Sensor Network, clustering scheme is used to prolong the lifetime of WSN by efficient usage of energy of sensor. In the distributed clustering protocol just like LEACH, every sensor in a network plays a cluster head role once during each epoch. So the FND is prolonged. But, even though every sensor plays a head role, the energy consumed by each sensor is different because the energy consumed increases according to the distance to the Base Station by the way of multiple increase. In this paper, we propose a mechanism to select a head depending on the distance to Base Station, which extends the timing of FND occurrence by 68% compared to the LEACH and makes network stable.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.13-20
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• 2008

Sensor network consists of a large number of sensor node distributed in the environment being sensed and controlled. The resource-constrained sensor nodes tend to have various and heterogeneous architecture. Thus, it is important to make its software environment platform-independent and reprogrammable. In this paper, we present BeeVM, a Java operating system designed for sensor networks. BeeVM offers a platform-independent Java programming environment with its efficiently executable file format and a set of class APIs for basic operating functions, sensing and wireless networking. BeeVM's high-level native interface and layered network subsystem allow complex program for sensor network to be short and readable. Our platform has been ported on two currently popular hardware platforms and we show its effectiveness through the evaluation of a simple application.