• 정보통신설비학회논문지
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• 제9권3호
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• pp.102-106
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• 2010

Recently process industries from oil and gas procedures and mining companies to manufactures of chemicals, foods, and beverages has been exploring the USN (Ubiquitous Sensor Networks) technology to improve safety of production processes. However, to apply the USN technology in the large-scale plant industry, reliability and security issues are not fully addressed yet, and the absence of the industrial sensor networking standard causes a compatibility problem with legacy equipment and systems. Although this situation, process industry such as energy plants are looking for the secure wireless plant solution to provide detailed, accurate safety monitoring from previously hard-reach, unaccordable area. In this paper, SPSF (Smart Plant Safety Framework based on Reliable-Secure USN) is suggested to fulfill the requirements of high-risk industrial environments for highly secure, reliable data collection and plant monitoring that is resistant to interference. The SPSF consists of three main layers: 1) Smart Safety Sensing Layer, 2) Smart Safety Network Layers, 3) Plant Network System Layer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2203-2217
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• 2016

To prevent structured peer to peer (P2P) overlay networksfrom being attacked by malicious nodes, a symmetric lookup-based routing algorithm referred to as Symmetric-Chord is proposed in this paper. The proposed algorithm determines the precision of routing lookup by constructing multiple paths to the destination. The selective routing algorithm is used to acquire information on the neighbors of the root. Authenticity of the root is validated via consistency shown between the information ascertained from the neighbors and information from the yet-to-be-verified root, resulting in greater efficiency of resource lookup. Simulation results demonstrate that Symmetric-Chordhas the capability of detecting malicious nodes both accurately and efficiently, so as to identify which root holds the correct key, and provides an effective approach to the routing security for the P2P overlay network.

• Journal of Communications and Networks
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• 제4권4호
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• pp.314-320
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• 2002

The various sectors of the International Telecommunication Union (ITU) have been addressing the evolution of thirdgeneration and future wireless systems in the context of a comprehensive International Mobile Telecommunications 2000 (IMT-2000) project, and within the ITU’s Telecommunication Standardization Sector (ITU-T) a Special Study Group on “IMT-2000 and Beyond” has been established to address the network aspects of these emerging wireless systems. The Special Study Group (SSG) is playing a global role in this general area, in which a number of regional standards development organizations and a variety of industry forums are also active. This paper provides background information on the SSG and describes the SSG’s ongoing work addressing medium-term issues relating to convergence of fixed and mobile systems and the harmonization of evolving IMT-2000 systems. The paper also addresses related mobility management aspects.

• Journal of information and communication convergence engineering
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• 제10권3호
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• pp.264-268
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• 2012

Tree-based structures offer assured optimal paths from the data source to the sink. Shortest routes are disregarded since these do not consider the remaining energy level of the nodes. This shortens the lifetime of the whole network. Most tree-based routing protocols, although aware of the nodes' energy, do not consider an energy aware sleep scheduling scheme. We propose an energy-aware sleep scheduling (EASS) scheme that will improve the sleep scheduling scheme of an existing tree-based routing protocol. An energy harvesting structure will be implemented on the wireless sensor network. The depth of sleep of every node will be based on the harvested energy.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.43-46
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• 2006

IEEE 802.16 WirelessMAN aiming to broadband wireless access (BWA) is evolving to 4G mobile communication system through the standardization of IEEE 802.16e supporting mobility on existing fixed WirelessMAN system. It is necessary for hand-over to provide seamless data service while MS (Mobile Station) moves to another BS (Base Station). Because the performance of handover affects packet loss or delay of any communications, it must consider low latency handover mechanism in packet based network. In this paper, we describes handover scheme of IEEE 802.16e with the cell edge interference problem and shows the way to solve the problem in frequency reuse one deployment. Our scheme reduces the handover latency and packet loss probability.

• Journal of Communications and Networks
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• 제11권2호
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• pp.187-195
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• 2009

The application of mathematical analysis to the study of wireless ad hoc networks has met with limited success due to the complexity of mobility, traffic models and the dynamic topology. A scenario based universal mobile telecommunications system (UMTS) time division duplex (TDD) opportunistic cellular system with an ad hoc behaviour that operates over UMTS frequency division duplex (FDD) licensed cellular network is considered. In this paper, we present a new routing metric which overall improves system performance in terms of interference and routing which operate in an ad hoc network in an opportunistic manner. Therefore we develop a simulation tool that addresses the goal of analysis and assessment of UMTS TDD opportunistic radio system with ad hoc behavior in coexistence with a UMTS FDD primary cellular networks.

• 전기학회논문지P
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• 제64권4호
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.273-278
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• 2007

In the next generation wireless mobile network, various methods are studied to offer interworking and mobility between various radio networks. To offer these harmoniously, network adaptation methods based on IP is generalized, and specifications of host-based mobility method with Mobile IPv4 and Mobile IPv6 to offer IP's mobility are defined in IETF specially. However, it is insufficient to satisfy quality of service that should be offered in wireless mobile network environment. Alternatively studies about Network-Based Mobility of Proxy Mobile IPv4, Proxy Mobile IPv6 etc. are preceded. This paper presents optimum plan that can offer mobility in the next generation radio transfer communication network by comparing and analyzing IP mobility methods divided by Host-based Mobility and Network-based Mobility.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.13-14
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• 2007

We propose HERAH(Hierarchical Energy-Aware Routing Algorithm for Heterogeneous Wireless Sensor Networks) that is the hierarchical routing algorithm in WSNs and is established on heterogeneous environment. HERAH performs CH selection by considering residual energy level and uses multi-hop communication within cluster. So, HERAH makes improvements in the energy savings and the network lifetime compared with LEACH.

• 한국항행학회논문지
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• 제19권6호
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• pp.601-606
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• 2015

최근 무선 데이터 서비스는 스마트폰을 중심으로 다양한 멀티미디어 기기들로 확산되고 있다. 무선 데이터 서비스는 과거 유선망을 기반으로 하는 데이터 서비스에서 모바일 기기를 이용한 무선 데이터 서비스로 대체되고, 특히 국내에서는 Wi-Fi (Wireless-Fidelity) 서비스 와 LTE (long term evolution) 서비스를 동시에 지원하는 단말기가 증가하고 있다. 현재 Wi-Fi 서비스망을 이용한 데이터 서비스는 무료로 제공되며, LET 망을 이용한 데이터 서비스는 유료로 제공 된다. 따라서 하나의 단말이 두 서비스를 동시에 지원하기 위해서 Wi-Fi 서비스를 우선순위로 하는 스마트 전환 기능을 제공하고 있다. 하지만 하나의 단말이 두 가지 서비스 지원을 위해 Wi-Fi 망과 LTE 망 사이에서 로밍과 핸드오버를 수행하는 과정 중 데이터 서비스가 멈추는 문제가 빈번히 발생되고 있다. 본 논문에서는 끊김 없는 무선데이터 서비스 지원을 위해 망과 망 전환 시 발생되는 데이터 서비스의 끊김 현상을 해결하기 위한 방법을 제안하였다.