• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.33-41
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• 2018

The idea of the Internet of Things as a platform on the Smart Campus has become increasingly popular. It requires an infrastructure consisting of communication networks, sensor nodes and gateways to connect to the Internet. Each sensor node is responsible for gathering data from the environment. This document outlines a network of wireless sensors on the Internet for the application of Smart Campus monitoring. Wireless sensor network Monitoring have become a complete solution to using a low power implementation and integrated systems. The numerous restrictions however result from the low communication range, the limited computing power, the lack of availability of the network protocol, the lack of programming security and the security failures in the areas of confidentiality, integrity and availability. A new security technique and its functionality for WSNM nodes developed. Development in the research of a secure network and suggestions for avoiding denial of service (DOS) and complexity attacks. These systems if properly implemented can provide an energy efficiency mechanism through pre-allocation and a new key from key management models with a secure routine algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.12
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• pp.1021-1026
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• 2016

The graph-based SLAM (Simultaneous Localization and Mapping) approach has been gaining much attention in SLAM research recently thanks to its ability to provide better maps and full trajectory estimations when compared to the filtering-based SLAM approach. Even though graph-based SLAM requires batch processing causing it to be computationally heavy, recent advancements in optimization and computing power enable it to run fast enough to be used in real-time. However, data association problems still require large amount of computation when building a pose graph. For example, to find loop closures it is necessary to consider the whole history of the robot trajectory and sensor data within the confident range. As a pose graph grows, the number of candidates to be searched also grows. It makes searching the loop closures a bottleneck when solving the SLAM problem. Our approach to alleviate this bottleneck is to sample a limited number of pose nodes in which loop closures are searched. We propose a heuristic for sampling pose nodes that are most advantageous to closing loops by providing a way of ranking pose nodes in order of usefulness for closing loops.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.4
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• pp.637-644
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• 2019

This paper describes an implementation of a graph-based simultaneous localization and mapping(SLAM) method called the General Graph Optimization. The General Graph Optimization formulates the SLAM problem using nodes and edges. The nodes represent the location and attitude of a robot in time sequence, and the edge between the nodes depict the constraint between the nodes. The constraints are imposed by sensor measurements. The General Graph Optimization solves the problem by optimizing the performance index determined by the constraints. The implementation is verified using the measurement data sets which are open for test of various SLAM methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.516-518
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• 2022

In this paper, we introduce a dependence of number of nodes of hidden-layer in fall detection system using Long Short-Term Memory that can detect falls. Its training is carried out using the parameter theta(θ), which indicates the angle formed by the x, y, and z-axis data for the direction of gravity using a 3-axis acceleration sensor. In its learning, validation is performed and divided into training data and test data in a ratio of 8:2, and training is performed by changing the number of nodes in the hidden layer to increase efficiency. When the number of nodes is 128, the best accuracy is shown with Accuracy = 99.82%, Specificity = 99.58%, and Sensitivity = 100%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.845-848
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• 2008

In case of application test in wireless sensor network, there are many difficulties in power supplying to wireless sensor node, installing and deploying of sensor nodes, maintaining and debugging. For efficient development and maintenance of wireless sensor network-based application, a simulator is essentially needed. However, the existing wireless sensor network simulators are focused to distribution of MAC address, routing, power management, it is not suitable to test the function of application in host which processes message through sink node. In this paper, we designed and implemented a log-based simulator for application running in host connected sink node.

• Journal of Korea Multimedia Society
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• v.17 no.8
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• pp.977-987
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• 2014

Many of the recent performance evaluation of clustering schemes in wireless sensor networks considered one sink node operation and fixed sink node location without mentioning about any network application requirements. However, application environments have variable requirements about their networks. In addition, network performance is sufficiently influenced by different sink node location scenarios in multi-hop based network. We also know that sink location can influence to the sensor network performance evaluation because of changed multipath of sensor nodes and changed overload spots in multipath based wireless sensor network environment. Thus, the performance evaluation results are hard to trust because sensor network is easily changed their network connection through their routing algorithms. Therefore, we suggest that these schemes need to evaluate with different sink node location scenarios to show fair evaluation result. Under the results of that, network performance evaluation results are acknowledged by researchers. In this paper, we measured several clustering scheme's performance variations in accordance with various types of sink node location scenarios. As a result, in the case of the clustering scheme that did not consider various types of sink location scenarios, fair evaluation cannot be expected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.893-895
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• 2012

The rapid spread of Internet and network technology advances the current USN (Ubiquitous Sensor Network) in order to realize research is taking place. USN individual sensor information of the sensor nodes to provide the service is equipped with various kinds of sensors. To do this, you can use a service unspecified XML-based Web services to leverage in the standardized data representation language is needed. In this paper, the required sensor information expressed in a standardized form for USN application service was designed in the sensor data representation language. The USN-based technologies and services in the field will be utilized to activate.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.142-149
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• 2007

Wireless sensor network technology is an emerging technology consisting of small, low power, and low cost devices that integrate limited computation, sensing, and radio communication capabilities. An ad-hoc home network system based embedded system for home environment monitoring was fabricated and tested. The wireless sensor node consists of a MCU, RF transceiver and sensors (temperature, humidity and light). Wireless sensor nodes run application software for data sampling and wireless communication, that was developed using 'nesC language' which runs on TinyOS. In our tests, acquired sensors data were monitored on 6.4" TFT-LCD of base-station through IEEE802.15.4 standard wireless communication. Also, the sensor data can be monitored by client user at the terminal PC to monitor environmental status of home in real time.

• Journal of KIISE:Information Networking
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• v.35 no.3
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• pp.207-214
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• 2008

There are lots of studies on application systems using wireless sensor networks. As the application systems are adapted to industrial field, the reliability of these systems becomes new key feature. The lack of reliability is an obstacle to extension of wireless sensor networks. In this paper, we propose the monitoring system framework that can offer the reliability of wireless sensor networks using a micro camera module and wireless sensor network nodes. And also we propose the efficient transfer method for image information over low rate wireless networks. Using these system framework and transfer method, we implement WiSN(Wireless image Sensor Network) based fire monitoring system.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.913-919
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• 2011

In this paper, we present a new efficient event detection algorithm for sensor networks with faults. We focus on multi-attributed events, which are sets of data points that correspond to interesting or unusual patterns in the underlying phenomenon that the network monitors. Conventional algorithms cannot detect some events because they treat only their own sensor readings which can be affected easily by environmental or physical problem. Our approach exploits spatio-temporal correlation of sensor readings. Sensor nodes exchange a fault-tolerant code encoded their own readings with neighbors, organize virtual sensor readings which have spatio-temporal correlation, and determine a result for multi-attributed events from them. In the result, our proposed algorithm provides improvement of detecting multi-attributed events and reduces the number of false-negatives due to negative environmental effects.