• Annual Conference of KIPS
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• 2005.05a
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• pp.1303-1306
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• 2005

무선 센서 네트워크는 저가의 많은 노드들로 구성되어 있으며. 이 노드들은 정보수집, 계산, 통신을 위한 전력등을 가지고 있다. 센서 네크워크에서의 보안을 위하여 주로 암호화 방법이 사용되고 있으나 자원이 제약적인 센서 네크워크에서 많은 에너지와 계산을 필요로 하는 암호화 방법은 센서 노드의 수명을 단축시킨다. 이를 보완하기 위하여 본 논문에서는 위치정보 은닉을 이용한 저전력 보안방법을 제안한다. 제안된 방법에서는 위치정보의 은닉을 위하여 상대거리정보를 사용하며, 센서 노드간 통신에서는 상대좌표로부터 구할 수 있는 노드사이의 상대거리정보가 사용된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1004-1014
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• 2007

In sensor networks, it is crucial to reliably and energy-efficiently deliver sensed information from each source to a sink node. Specifically, in mobile sink (user) applications, due to the sink mobility, a stationary dissemination path may no longer be effective. The path will have to be continuously reconfigured according to the current location of the sink. Moreover, the dynamic optimal path from each source to the sink is required in order to reduce end-to-end delay and additional energy wastage. In this paper, an Adaptive Reversal Optimal path Tree (AROT) protocol is proposed. Information delivery from each source to a mobile sink can be easily achieved along the AROT without additional control overhead, because the AROT proactively performs adaptive sink mobility management. In addition, the dynamic path is optimal in terms of hop counts and the AROT can maintain a robust tree structure by quickly recovering the partitioned tree with minimum packet transmission. Finally, the simulation results demonstrate that the AROT is a considerably energy-efficient and robust protocol.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.67-73
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• 2010

A Wireless Sensor Network(WSN) is a promising infrastructure for the future U-healthcare system. In a WSN for the U-healthcare system, both biometric data and location data are transferred hierarchically from lots of mobile patients to the base station server and some countermeasures are made in real time if necessary. In this process, we encounter the load-balancing problem when many patients gather in a specific area. We also encounter the data duplication problem when each patient moves into an area monitored by several supervisors. The second problem is closely related to the first one. In this paper, we propose a mobile patient monitoring system with priority-based policy in load-balancing to solve the previous two problems and perform a DEVS Java-based system simulation to verify the system efficiency.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.2
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• pp.43-58
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• 2004

Up-to-date cargo transport system, CVO(Commercial Vehicle Operations) is the system to manage efficiently cargo distribution as providing at real time the information of cargo location and situation through ITS and GPS technology. In this paper, we proposed the Gate Automation System of harbors among AEI/AVI. To implement his system, we use the DSRC/RFID(Dedicated Short Range Communication / Radio Frequency IDentification) which adopts an wireless communication between RSE(Road-side Equipment) and OBE(on-Board Equipment) on a vehicle. When constructing the Gate automation system of harbors, the business application ability are reviewed practically and the logistics facilities to be constructed in the near future may use this project results according to the international standard and it could help complete integrated logistics system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1177-1184
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• 2008

Non-line-of-sight (NLOS) propagation can severely weaken the accuracy of ranging and localization in wireless location systems. NLOS bias mitigation techniques have recently been proposed to relieve the NLOS effects, but positively rely on the capability to accurately distinguish between LOS and NLOS propagation scenarios. This paper proposes an energy-capture-based NLOS identification method for LDR-UWB systems, based on the analysis of the characteristics of the channel impulse response (CIR). With this proposed energy capture method, the probability of successfully identifying NLOS is much improved than the existing methods, such as the kurtosis method, the strongest path compare method, etc. This NLOS identification method can be employed in adaptive modulation scheme to decrease bit error ratio (BER) level for certain signal-to-noise ratio (SNR). The BER performance with the adaptive modulation can be significantly enhanced by selecting proper modulation method with the knowledge of channel information from the proposed NLOS identification method.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.202-208
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• 2014

Wireless network information services allow end systems to discover heterogeneous networks and spectrum available for secondary use at or near their current location, helping them to cope with increasing traffic and finite spectrum resources. We propose a unified architecture that allows end systems to find nearby base stations that are using either licensed, shared or unlicensed spectrum across multiple network operators. Our study evaluates the performance and scalability of spatial databases storing base station coverage area geometries. The measurement results indicate that the current spatial databases perform well even when the number of coverage areas is very large. A single logical spatial database would likely be able to satisfy the query load for a large national cellular network. We also observe that coarse geographic divisions can significantly improve query performance.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1930-1935
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• 2008

Bimodal tram is able to run both general and special road. It has also the advantages of both public bus and subway which have the charateristics of easiness to approach and punctuality respectively. These advantages are accomplished by the cooperative communication between the control center and bimodal tram which is running with the fleet. This paper have investigated the requirement analysis and designing of the car operating computer system which have the functions of communication, broadcasting and display. car operating computer system communicates between bimodal tram and control center with wireless antenna. It can also transmit the location and status information of bimodal tram to control center for managing the bimodal tram fleet on road efficiently and economically.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.31-37
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• 2011

Recently, MANET(Mobile Ad-hoc Network) is developing increasingly in the wireless network. MANET has weakness because phases change frequently and MANET doesn't have middle management system. Every node which consists of MANET has to perform data forwarding, but traceback is not reliable if these nodes do malicious action owing to attack. It also is not easy to find location of attacker when it is attacked as moving of nodes. In this paper, we propose a hierarchical-based traceback method that reduce waste of memory and can manage path information efficiently. In order to manage trace path information and reduce using resource in the cluster head after network is formed to cluster, method which recomposes the path efficiently is proposed. Proposed method in this paper can reduce path trace failure rate remarkably due to moving of nodes. It can also reduce the cost for traceback and time it takes to collect information.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.262-265
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• 2008

수천 개의 센서 노드들 간의 공동 작업을 기반으로 한 무선 센서 네트워크는 대규모 서식지 모니터링, 침입 탐지, 자동화된 실시간 위치 평가, 홈 어플리케이션, 과학적인 탐사 등 수많은 응용에 대한 새로운 플랫폼을 제공하고 있다. 본 논문은 수천 개의 센서노드들이 센서 필드에 전개되어 있는 경우에 센서 노드의 상태를 효율적으로 관리하기 위해 센서 노드의 위치를 탐지하기 위한 방법에 관하여 기술하였다. 기본적으로 PEGASIS 라우팅 알고리즘을 이용하여 노드들 간의 상대 거리 정보를 수집하여 센서 노드의 위치 정보를 탐지하였다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.147-166
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• 2004

최근 정보기술의 동향을 살펴보면 공통적인 키워드를 발견할 수 있는데, 그것은 바로 모바일(Mobile)이다. 이에 GIS 분야에서도 무선환경에서의 GIS 활용을 위한 기술이 확산되고 있으며, 대표적인 기술로 LBS(Location Based Service)와 모바일 GIS(Mobile GIS)가 있다. 이러한 배경하에 선진국가에서는 고도화된 전자정부 구현을 위해 무선 GIS 기술적용이 추진되고 있으며, 국내에서도 모바일 전자정부 추진계획이 수립되었다. 이에 본 논문에서는 공공분야에서 효율적인 무선 GIS 기술도입을 위해 공공분야의 무선 GIS라는 개념을 제시하고, 무선 GIS 서비스 구현의 기반이 되는 서비스 유형을 제시하였다. 공공분야의 무선 GIS 서비스 유형은 LBS와 모바일 GIS를 기반으로 적용 가능한 업무유형과 무선 GIS 특성에 따른 서비스 구조로 구분하여 고찰하였으며, 두 내용을 종합하여 공공분야의 무선 GIS 서비스유형을 제시하였다. 제시된 무선 GTS 서비스 유형은 향후 모바일 전자정부 및 공공분야에서의 모바일 관련 GIS 서비스 구현시 참조할 수 있을 것이라 예상된다.