• 한국정보과학회논문지:정보통신
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• 제32권6호
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• pp.687-695
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• 2005

최근 무선 접속망의 급속한 발전으로 이동 통신 환경에서 인터넷 서비스 제공에 대한 요구가 늘어남에 따라, IP기반의 이동성 지원과 마이크로 이동성에 따른 위치관리 트래픽을 줄일 수 있도록 해주는 HMIPv6 프로토콜이 제안되었다. HMIPv6에 페이징을 적용함으로써 MN의 위치등록에 필요한 시그널링 및 위치정보 데이타베이스의 갱신을 위한 처리를 줄일 수 있다. 본 논문에서는 각기 다른 특성을 갖는 이동 노드들에 하나의 동일한 페이징 영역이 정적으로 적용되는 것이 아닌, 각 이동 노드의 특성를 고려하여 각각의 이동 노드에 적합한 최적의 페이징 영역이 설정되는 HMIPv6 환경에서의 새로운 동적 페이징 기법(DP-HMIPv6)을 제안한다. 수학적 성능 분석을 통해 정적 페이징 기법보다 제안 기법인 동적 페이징 기법을 이용하였을 때 비용이 절감되었음을 확인 할 수 있었다. 또한 네트워크 상에 이동 노드의 수가 많아질수록 동적 페이징 기법을 통한 비용 절감은 더욱더 효과적임을 알 수 있다.

• 한국산업정보학회논문지
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• 제11권5호
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• pp.141-149
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• 2006

Ubiquitous computing environment means the computing environment that has taken its position so closely with the ordinary living so much like air or water. In building up the U-Korea, one of the important issues is the social issue from the drasticincrease of senior population. The contemporary society has its distinct trend in increase of senior household following the nuclear family orientation, increase of working parents with the advancement of women in society, unable to support seniors for long distance or short distance of business trip and other reasons that the need of senior welfare has been ever more felt. Accordingly, the Ministry of Government Affairs and Home Administration has developed the wireless paging system to make prompt response system for 119 Rescue when the single senior is encountered with emergency situation that is has been widely provided for the socially neglected people such as single senior, the disabled persons and others. Currently, the wireless paging system is operated as the sub-system for emergency rescue informationsystem, but due to the lack of reliability of product, problems of terminal portable transmitter, receptor and others, rejection of beneficiary and lack of knowledge in use, insufficient management and supervision of managing officers, the efficiency has been declined that there is a need of development for the system. Therefore, this study proposes the context aware information structure of the subject of ubiquitous wireless paging system required forthe development of the wireless paging system model of ubiquitous environment that improved the problems of currently operated wireless paging system.

• 대한산업공학회지
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• 제25권3호
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• pp.321-329
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• 1999

An efficient location management for mobile stations plays an important role in mobile communication network. This paper studies a movement-based registration(MBR) method with a selective paging scheme. In the movement-based registration method, a mobile station performs a location registration when the number of cell boundary crossings since the last registration equals to the given movement threshold. In the selective paging scheme, the network first partitions the location area of the called mobile station into a number of subareas and then pages each subarea one after another until the MS is found. To reduce the paging and registration load, we propose a modified MBR(MMBR) method in the aspect of minimization of signaling traffic on radio channels. First, we propose a new establishment of the paging area to reduce the paging load on radio channels and then analyze its effects. Next, we propose the MMBR to reduce the registration load. Numerical results show that our proposed movement-based registration provides the better performance compared with the conventional method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.74-77
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• 1998

We consider connection-oriented wireless cellular networks. These networks employ dedicated radio channels for the transmission of signaling information. A forward signaling channel is a common signaling channel assigned to carry the multiplexed stream of paging and channel allocation(virtual circuit allocation) packets from a base station to mobile stations. The delay levels experienced by paging and channel allocation packets have serious effect on the utilization level of the limited radio channel capacity. While a slotted mode operation is used to reduce the power consumption level at mobile stations, it may induce an increase in packet delay levels. In this paper, we thus consider a multiplexing scheme for paging and channel allocation packets under which slots are dynamically allocated for the paging packet transmission. For this dynamic scheme, we develop an analytical method for deriving the delay characteristics exhibited by paging and channel allocation packets, and investigate the effect of network parameters on the delay level by using this method.

• Journal of Information Technology Applications and Management
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• 제13권2호
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• pp.115-126
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• 2006

Recently, flash memories are one of best media to support portable computer's storages in mobile computing environment. We propose a new transaction recovery scheme for a flash memory database environment which is based on a flash media file system. We improved traditional shadow paging schemes by reusing old data pages which are supposed to be invalidated in the course of writing a new data page in the flash file system environment. In order to reuse these data pages, we exploit deferred cleaning list structure in our flash memory shadow paging (FMSP) scheme. FMSP scheme removes the additional storage overhead for keeping shadow pages and minimizes the I/O performance degradation caused by data page distribution phenomena of traditional shadow paging schemes. We also propose a simulation model to show the performance of FMSP. Based on the results of the performance evaluation, we conclude that FMSP outperforms the traditional scheme.

• Journal of Communications and Networks
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• 제7권2호
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• pp.126-134
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• 2005

Reducing energy consumption in mobile hosts (MHs) is one of the most critical issues in wireles/mobile networks. IP paging protocol at network layer and power saving mechanism (PSM) at link layer are two core technologies to reduce the energy consumption of MHs. First, we investigate the energy efficiency of the current IEEE 802.11 power saving mechanism (PSM) when IP paging protocol is deployed over IEEE 802.11 networks. The result reveal that the current IEEE 802.11 PSM with a fixed wakeup interval (i.e., the static PSM) exhibits a degraded performance when it is integrated with IP paging protocol. Therefore, we propose an adaptive power saving mechanism in IEEE 802.11-based wireless IP networks. Unlike the static PSM, the adaptive PSM adjusts the wake-up interval adaptively depending on the session activity at IP layer. Specifically, the MH estimates the idle periods for incoming sessions based on the exponentially weighted moving average (EWMA) scheme and sets its wake-up interval dynamically by considering the estimated idle period and paging delay bound. For performance evaluation, we have conducted comprehensive simulations and compared the total cost and energy consumption, which are incurred in IP paging protocol in conjunction with various power saving mechanisms: The static PSM, the adaptive PSM, and the optimum PSM. Simulation results show that the adaptive PSM provides a closer performance to the optimum PSM than the static PSM.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.55-60
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• 2005

Ubiquitous computing environment means the computing environment that has taken its position so closely with the ordinary living so much like air or water. In building up the U-Korea, one of the important issues is the social issue from the drastic increase of senior population. The contemporary society has its distinct trend in increase of senior household following the nuclear family orientation, increase of working parents with the advancement of women in society, unable to support seniors for long distance or short distance of business trip and other reasons that the need of senior welfare has been ever more felt. Accordingly, the Ministry of Government Affairs and Home Administration has developed the wireless paging system to make prompt response system for 119 Rescue when the single senior is encountered with emergency situation that is has been widely provided for the socially neglected people such as single senior, the disabled persons and others. Currently, the wireless paging system is operated as the sub-system for emergency rescue information system, but due to the lack of reliability of product, problems of terminal portable transmitter, receptor and others, rejection of beneficiary and lack of knowledge in use, insufficient management and supervision of managing officers, the efficiency has been declined that there is a need of development for the system. Therefore, this study proposes the context aware information structure of the subject of ubiquitous wireless paging system required for the development of the wireless paging system model of ubiquitous environment that improved the problems of currently operated wireless paging system.

• 한국경영과학회지
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• 제30권3호
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• pp.119-135
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• 2005

Design of location erea(LA) in a cellular network is to partition the network into clusters of cells so as to minimize the cost of location updating and paging. Most research works dealing with the LA design problem assume that the call. arrival rate and mobile flow rate are fixed parameters which can be estimated independently. In this aspect, most Problems addressed so far are deterministic LA design problems(DLADP), known to be NP hard. The mobile flow and call arrival rate are, however, varying with time and should be treated simultaneously because the call arrival rate in a cell during a day is influenced by the change of a population size of the cell. This Paper Presents a new model on IA design problems considering the time-dependent call arrival and mobile flow rate. The new model becomes a stochastic LA design problem(SLADP) because It takes into account the possibility of paging waiting and blocking caused by the changing call arrival rate and finite paging capacity. Un order to obtain the optimal solution of the LA design problem, the SIADP is transformed Into the DLADP by introducing the utilization factor of paging channels and the problem is solved iteratively until the required paging quality is satisfied. Finally, an illustrative example reflecting the metropolitan area, Seoul, is provided and the optimal partitions of a cell structure are presented.

• 대한전자공학회논문지TC
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• 제44권10호
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• pp.29-36
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• 2007

무선 IP 네트워크에서 단말의 이동성 지원 방법의 문제점을 해결하기 위한 기존의 IP 페이징 기법은 페이징 영역내의 라우터를 이동하는 idle 상태의 이동단말이 등록을 수행하지 않아 등록 메시지와 오버헤드를 감소시키는 효과가 있다. 하지만, 최근 IP 기반 무선 센서 네트워크에 대한 연구와 구현이 활발한 시점에서 IP 페이징 기법을 이러한 환경에 바로 적용할 경우 지속적인 페이징 신호 수신 시도로 인하여 이동단말이 전력을 과도하게 소비한다는 문제점을 가지고 있다. 본 논문에서는 이를 해결하고자 센서 네트워크와 이동단말의 특징을 이용한 가변적 페이징 주기에 근거한 동기화된 간헐적 페이징 수신 기법을 제안한다. 수학적 분석의 결과는 제안하는 방법에서 이동성과 페이징 영역 내의 라우터의 개수가 감소할수록 단말의 전력 소모가 현저히 감소함을 보여준다. 또한 제안하는 방법에 사용된 파라미터를 조정함으로써 기존의 연속적 페이징 수신 기법으로의 전환은 물론 이동단말의 전력 소비 정보 및 간헐적 페이징 수신 기법으로 인한 지연 등을 조정할 수 있어 IP 기반의 무선 센서 네트워크에 효과적으로 적용될 것으로 기대된다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.222-225
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• 2003

최근 공중 무선랜 서비스와 같이 IP 기반의 액세스 망을 사용하는 네트워크 환경이 증가하고, IT를 기반으로 하는 차세대 네트워크 환경이 대두됨에 따라 IP 기반의 이동성 관리 기술의 필요성이 증가하고 있다. IP 기반의 이동성 지원을 위해 MIPv6 프로토콜이 제시되었으며, 위치관리를 위한 트래픽을 줄이기 위해 지역 내에서의 이동성을 따로 관리하는 HMIPv6 프로토콜이 제시되었다. 또한 이동통신 망에서 사용하는 페이징 기술을 IP 망에서 사용함으로써 망이 단말의 개략적인 위치만 관리하도록 하여 위치 등을 위한 트래픽을 줄이고 단말의 전력 소모를 줄이는 IP 페이징 기술이 소개되었다. 본 논문에서는 페이징 서비스를 제공함으로써 지역 내의 이동성 관리를 위한 트래픽을 효과적으로 줄일 수 있는 P-HMIPv6 프로토콜을 제안한다.