• 한국컴퓨터정보학회논문지
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• 제12권6호
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• pp.115-121
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• 2007

최근 유비쿼터스 컴퓨팅 환경에서 위치 추적 및 길찾기 서비스와 같은 위치 기반 서비스가 빠르게 발전하고 있다. 또한, 사용자 또는 사물의 위치가 다양한 장치 및 방법으로 획득되고 있다. 그러나, 기존의 위치 데이터 관리 시스템은 단일 위치 획득 시스템만을 기반으로 하여 설계되어 있어서 이러한 유비쿼터스 컴퓨팅 환경에는 많은 문제를 가지게 된다. 따라서, 본 논문에서는 유비쿼터스 컴퓨팅 환경의 다양한 센서로부터 획득되는 대용량의 위치 데이타를 효율적으로 저장하고 관리할 수 있는 위치 데이타 관리 시스템과 효율적인 위치 데이타 갱신을 위한 갱신 전략을 제시하였다. 특히, 본 논문에서 제시한 위치 데이타 관리 시스템은 유비쿼터스 컴퓨팅 환경에서 위치 기반의 효율적인 context-aware 서비스나, 자동화 서비스에 중요한 컴포넌트로 제공될 수 있다.

• Journal of Communications and Networks
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• 제15권2호
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• pp.153-163
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• 2013

In recent years, more and more researches have been focusing on trust management of vehicle ad-hoc networks (VANETs) for improving the safety of vehicles. However, in these researches, little attention has been paid to the location privacy due to the natural conflict between trust and anonymity, which is the basic protection of privacy. Although traffic safety remains the most crucial issue in VANETs, location privacy can be just as important for drivers, and neither can be ignored. In this paper, we propose a beacon-based trust management system, called BTM, that aims to thwart internal attackers from sending false messages in privacy-enhanced VANETs. To evaluate the reliability and performance of the proposed system, we conducted a set of simulations under alteration attacks, bogus message attacks, and message suppression attacks. The simulation results show that the proposed system is highly resilient to adversarial attacks, whether it is under a fixed silent period or random silent period location privacy-enhancement scheme.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.388-394
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• 2007

In wireless network, we propose a predictive location update scheme which considers mobile user's(MU's) mobility patterns. MU's mobility patterns can be found from a movement history data. The prediction accuracy and model complexity depend on the degree of application of history data. The more data we use, the more accurate the prediction is. As a result, the location management cost is reduced, but complexity of the model increases. In this paper, we classify MU's mobility patterns into four types. For each type, we find the respective optimal number of application of history data, and predictive location area by using the simulation. The optimal numbers of four types are shown to be different. When we use more than three application of history data, the simulation time and data storage are shown to increase very steeply.

• 전기학회논문지
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• 제56권7호
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• pp.1309-1314
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• 2007

The assignment of cells to reporting or non-reporting cells is an NP-hard problem having an exponential complexity in the Reporting Cell Location Management (RCLM) system. Frequent location update may result in degradation of quality of service due to interference. Miss on the location of a mobile terminal will necessitate a search operation on the network when a call comes in. The number of reporting cells and which cell must be reporting cell should be determined to balance the registration (location update) and search (paging) operations to minimize the cost of RCLM system. T1is paper compares Max-Min ant system (MMAS), rank-based ant system (RAS) and hybrid method of MMAS and RAS that generally used to solve combinatorial optimization problems. Experimental results demonstrate that hybrid method of MMAS and RAS is an effective and competitive approach in fairly satisfactory results with respect to solution quality and execution time for the optimal design of location management system.

• 보건행정학회지
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• 제9권3호
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• pp.21-32
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• 1999

The purpose of this study is to assess individual decisive factors for distribution of medical specialists in Korea. A data set was constructed using several published data sources. including the Korean Medical Association's physician master file as a principal source for physician information. Linear logistic regression analysis was performed to assess the relationship between the location of private specialist clinic for practice with six variables related with individual characteristics: age. sex. location of postgraduate training hospital. location of medical school graduated, size of hospital for training, and specialty. Analysis showed that location of practice. classified into urban and rural areas, was significantly associated with the variables of sex. location of postgraduate training hospital. location of medical school. In addition, significant association was found between the location of practice which was categorized into "near-Seoul area" and others, and sex, location of postgraduate training hospital. and location of medical school. We could conclude that to improve area maldistribution of physicians locations of hospitals for training and medical schools have to have the highest priority in the policymaking.icymaking.

• 경영과학
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• 제25권2호
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• pp.73-80
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• 2008

The location area planning is to assign cells to the location areas of a wireless communication network in an optimum manner. The two important cost components are cost of location update and cost of paging that are of conflicting in nature; i.e., minimizing the registration cost might increase the search cost. Hence, it is important to find a compromise between the location update and paging operations such that the cost of mobile terminal location tracking cost is a minimum. The complete mobile network is divided into location areas. Each location area consists of a group of cells. In fact this is shown to be an NP-complete problem in an earlier study. In this paper, we use an ant colony optimization method to obtain the best/optimal group of cells for a given a network.

• 디지털콘텐츠학회 논문지
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• 제11권4호
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• pp.433-443
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• 2010

본 논문에서는, 무선 셀룰러 네트워크와 Mobile IP 기반의 네트워크를 위해 제안되었던 기존의 다양한 위치 관리 기법들에 대한 광범위한 소개 및 분류법을 제시한다. 또한, 기존에 제안되었던 다양한 위치 관리 기법들로부터, 네트워크의 종류와 관계없이 위치 관리 기법들의 이해를 돕기 위한 유용한 가이드를 제공할 수 있는 공통의 핵심 기술들 및 주요 설계상의 목표와 성능 고려 사항 등을 도출해 낸다. 본 논문의 목적은 위치 관리를 위한 새로운 기법을 제안하는 것이라기보다는, 기존에 제안되었던 위치관리 기법들의 다양한 설계상의 핵심적인 특징들을 도출해내고, 차세대 무선 이동 네트워크에서 보다 효율적이고 최적화된 위치 관리 기법을 설계하기 위해 근간이 되는 핵심 개념 및 기술들에 대한 통찰력을 향상시키는 것을 그 목적으로 한다. 또한, 이러한 근간이 되는 개념 및 기술들은 네트워크의 종류와 관계없이 향후의 이동 컴퓨팅 환경에서 보다 효율적인 이동성 및 서비스 품질 제공을 위해서도 쉽게 적용될 수 있을 것으로 기대되는 바이다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.473-476
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• 2008

유비쿼터스 센서 네트워크는 홈 네트워크, 텔레매틱스 등의 IT 산업분야를 비롯하여 물류, 유통, 환경, 교통 등 산업 전반에 다양하게 응용되고 있으며 이들 기술이 공통적으로 요구하는 기술 요소 중의 하나는 센서노드의 위치에 관한 정보를 추적하고 관리하는 것이다. 본고에서는 무선 센서 네트워크의 응용분야로서 무선센서노드의 전파수신강도(RSS)에 기반한 위치측정 기법을 캠퍼스 내 차량 위치 측정에 활용하는 것을 제안하고 그 구현방안에 대하여 기술하였다. 이를 위하여 무선센서노드의 최적의 경로 탐색 및 멀티홉 설정 방안을 고찰하였으며 실제 적용 시스템의 구성 및 동작 절차를 제안하였다. 실외환경에서의 실험 결과 제안된 방식은 캠퍼스환경에서 차량의 주차위치를 관리하기에 충분한 위치 정확도를 제공하는 것으로 판명되었다.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2004년도 International Conference on Digital Policy & Management
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• pp.185-202
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• 2004

Recent development in wireless computing and GPS technology cause the active development in the application system of location information in real-time environment such as transportation vehicle management, air traffic control and location based system. Especially, study about vehicle location tracking system, which monitors the vehicle's position in a control center, is appeared to be a representative application system. However, the current vehicle location tracking system can not provide vehicle position information that is not stored in a database at a specific time to users. We designed a vehicle location tracking system that could track vehicle location using mobile interface such as PDA. The proposed system consist of a vehicle location retrieving server and a mobile interface. It is provide not only the moving vehicle's current location but also the position at a past and future time which is not stored in database for users.

• 한국경영과학회지
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• 제31권4호
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• pp.139-155
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• 2006

The facility location problem of this paper is distinguished from the maximal covering location problem and the flxed-charge facility location problem. We propose the maximal profiting location problem (MPLP) that is the facility location problem maximizing profit with multi-product. We apply to the simulated annealing algorithm, the stochastic evolution algorithm and the accelerated simulated annealing algorithm to solve this problem. Through a scale-down and extension experiment, the MPLP was validated and all the three algorithm enable the near optimal solution to produce. As the computational complexity is increased, it is shown that the simulated annealing algorithm' is able to find the best solution than the other two algorithms in a relatively short computational time.