• Journal of KIISE
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• v.44 no.7
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• pp.726-732
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• 2017

In practical distributed sensing and prediction applications over wireless sensor networks (WSN), environmental sensing activities are highly dynamic because of noisy sensory information from moving source signals. The recent distributed online convex optimization frameworks have been developed as promising approaches for solving approximately stochastic learning problems over network of sensors in a distributed manner. Negligence of mobility consequence in the original distributed saddle point algorithm (DSPA) could strongly affect the convergence rate and stability of learning results. In this paper, we propose an integrated sliding windows mechanism in order to stabilize predictions and achieve better convergence rates in cooperative detection of a moving source signal scenario.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4B
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• pp.184-191
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• 2008

NanoQplus, which is an embedded operating system for wireless sensor networks (WSNs) and developed by Electronics and Telecommunications Research Institute (ETRI), provides programmer-friendly preemptive multi-threading programming technique, but it has poor network protocol stack, as compared to TinyOS, one of the famous operating systems for WSNs. In this paper, we apply dynamic MANET on-demand routing (DYMO) protocol, which is being standardized in Internet Engineering Task Force (IETF), to NanoQplus. Since DYMO has been proposed for mobile ad-hoc networks (MANETs) and MANETs have less resource restrictions than WSNs, the basic DYMO protocol cannot be applied to WSNs without modifications. Moreover, coherence with MAC protocol should be considered in order to eliminate redundant data between MAC and network layers. Thus, we propose a modified version of the basic DYMO protocol for NanoQplus. The experimental results from a real sensor network test-bed show that the DYMO implementation using NanoQplus works efficiently in WSNs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.659-661
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• 2011

In this paper, we propose a study of scheme to detect mobile object. In special zone needed detection, sensor network based system development can provide safety of pedestrian. Instead current CCTV, intelligent sensor network and service can provide reliability to guarantee safe zone. Base on pedestrian characteristic, if unusual situation is detected and it is included in previous agreed scenario, safety service can be provided.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1134-1141
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• 2008

As sensor network technologies developed, the sphere field of application is escalated unfortunately, the applicable size is smaller than the actual quantity of cattle in feedlot. In this paper, we simulated and evaluated biological data transmission performance of virtual cattle feedlot. Deducted conclusions show us a more efficient cattle control scenario is required and effective routing protocol design and modification are needed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.637-646
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• 2012

Recently, Wireless Sensor Networks (WSNs) are used in many applications. When sensor nodes are deployed on special areas, where humans have any difficulties to get in, the nodes form network topology themselves. By using the sensor nodes, users are able to obtain environmental information. Due to the lack of the battery capability, sensor nodes should be efficiently managed with energy consumption in WSNs. In specific applications (e.g. in intrusion detections), intruders tend to occur unexpectedly. For the energy efficiency in the applications, an appropriate algorithm is strongly required. In this paper, we propose tree-based routing algorithm for the specific applications, which based on the intrusion detection. In addition, In order to decrease traffic density, the proposed algorithm provides enhanced method considering link cost and load balance, and it establishes efficient links amongst the sensor nodes. Simultaneously, by using the proposed scheme, parent and child nodes are (re-)defined. Furthermore, efficient routing table management facilitates to improve energy efficiency especially in the limited power source. In order to apply a realistic military environment, in this paper, we design three scenarios according to an intruder's moving direction; (1) the intruder is passing along a path where sensor nodes have been already deployed. (2) the intruders are crossing the path. (3) the intruders, who are moving as (1)'s scenario, are certainly deviating from the middle of the path. In conclusion, through the simulation results, we obtain the performance results in terms of latency and energy consumption, and analyze them. Finally, we validate our algorithm is highly able to adapt on such the application environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.79-84
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• 2009

Recently, many researches are being carried out on monitoring animal behaviour and interactions with the environment using sensor networks and for tracing animal chain management and identifying animals using RFID techniques. And we are studying about the management and burglarproof of a pet using GPS technique. But there is a lack of study for providing users intelligence services in zoo using GPS, RFID, and sensor networks. Accordingly, in this paper, we propose a intelligence tracking service of animal situation based on GPS, RFID, and sensor in zoo. Firstly, we present a tracking service scenario of animal situation and system configuration according to this scenario. The proposed service provides users realtime animal situation information of animal like the present location, temperature, image, etc. In addition, we can chase the animals to know a location and situation of animal when the animals escapes from their cages. Next, we implement and test prototype operations of animal tracking system based on this scenario to verify the proposed service.

• Fire Science and Engineering
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• v.24 no.1
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• pp.72-80
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• 2010

This study suggests ubiquitous railway disaster prevention system that gearing Ubiquitous Sensor Network system information take to the subway fire accident information which emergency response procedure as occurring subway fire accident scenario. Also it is proposed that emergency response system though fire scenario. collected Information was analyzed each system over providing information and it is designed to exchanging information structure though relation system. The ubiquitous railway disaster prevention system basically consists by four unit stages as prevention, preparedness, response and recovery system. Especially, in this system can supply real time accident information to the relevant government offices and public through forecasting and warning system by utilizing recognition of the five senses in case of accident. also, it is build that to make decisions as linking 2-dimension and 3-dimension space information interface of ubiquitous sensor networks and expected scenarios.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.802-807
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• 2006

유비쿼터스 컴퓨팅 시스템은 무선 네트워크와 모바일 네트워크 환경과 함께 발전하고 있으며, 일부에서 실제 유비쿼터스 컴퓨팅 시스템이 우리 생활에 사용되고 있고, 앞으로는 더 많이 이용 될 것이다. 이러한 유비쿼터스 시스템을 여러 분야에 적용시키기 위해서 실제 유비쿼터스 시스템을 설계, 구축하고 적절한 시나리오에 맞추어서 동작시켜봄으로써 유비쿼터스 시스템의 발전에 도움을 줄 수 있을 것이다. 또한 이러한 시스템을 설계하기 위하여 센서, DB, PDA등의 여러 장비를 실제 다뤄 볼 수 있고, 이러한 시스템을 보다 안전하게 제어하는 기술을 습득하고 이러한 시스템을 실제 생활에 적용시키는 시나리오에 대하여 분석한다.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.123-126
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• 2016

Energy efficiency in heterogeneous network is considered as one of the main issues when deploying the wireless sensor network. In heterogeneous network, the random distribution of initial energy at each node could lead to an instability of the network. Therefore, a resonable policy must be established in order to maintain the fairness in energy consumption and extend the working time of each node in the network. In this paper, we evaluate the performance of the distributed clustering protocol (DCP) in heterogeneous network on different scenarios. Simulation results are compared with the results of a LEACH protocol in a heterogeneous network. In addition, the performance of system in heterogeneous network are also compared with the homogeneous network to illustrate the effect of imbalance in the initial energy on the life time of each node in the system. The result illustrates that the DCP protocol demonstrates better performance than LEACH protocol in both the heterogeneous and the homogeneous networks.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.1-10
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• 2006

Ubiquitous computing, a new type of network environment has been generating much interest recently and has been actively studied. In ubiquitous computing, the sensor network which consists of low electric power ad-hoc network-based sensors and sensor nodes, is particularly the most important factor The sensor network serves as the mediator between ubiquitous computing and the actual environment. Related studies are focused on network . management through lightweight hardware using RFID. However, to apply these to actual environment, more practical scenarios as well as more secured studies equipped with secures and efficiency features are needed. Therefore, this study aims to build a wireless network based on PTD for multi users, which provides the largest utility in individual networks, and propose an appropriate management method. The proposed method is designed to enhance security and efficiency related to various services required in wireless networks, based on the reliable peripheral devices for users or pm. using pm, which has been applied to electronic commerce transactions in existing papers, this study also proposed an appropriate management method that is suitable for a dynamic environment and setting a temporary group to provide various services.