• 한국정보과학회논문지:시스템및이론
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• 제26권9호
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• pp.1135-1144
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• 1999

본 논문에서 우리는 셀룰러 통신 시스템을 위한 위치갱신과 위치질의 비용을 줄일 수 있는 새로운 위치관리 기법을 제안한다. 위치갱신 및 위치질의 비용을 줄이기 위하여, 제안한 위치관리 기법은 사용자 지역성을 사용한다. 사용자 지역성은 이동 지역성과 호 지역성으로 이루어진다. 이동 지역성을 갖는 이동단말들을 위한 위치갱신은 지역 PVLR(Proxy-Visitor Location Register) 갱신에 의해 위치갱신 비용을 줄일 수 있다. 호 지역성을 갖는 이동단말들을 위한 위치질의는 지역 PVLR 질의에 의해 위치질의 비용을 줄일 수 있다. 분석 모델을 통하여, 제안한 기법의 성능 분석과 IS-41 표준과 제안 기법과의 성능을 비교한다. 사용된 비교 척도는 네트워크 비용, 데이타베이스 비용 그리고 호 설정 지연이다. 이들 모든 척도들에 대해서, 제안 기법이 IS-41 표준에서 정의된 위치관리 기법보다 더 좋은 성능을 보인다. 또한 비교 결과는 CMR(Call-to-Mobility Ratio)에 상관없이 제안 기법이 IS-41 기법보다 성능이 좋음을 보여준다. Abstract In this paper, we propose a new location management scheme for cellular communication systems with the goal of reducing both location update and query cost. In order to reduce both location update and query cost, the proposed scheme uses user locality. User locality consists of movement and call locality. For mobile terminals with movement locality, location update cost is reduced by local PVLR(Proxy-Visitor Location Register) update. Location query cost is reduced by local PVLR query for mobile terminals with call locality. Through analytical models, we analyze the performance of the proposed scheme and compare it with that of the IS-41 scheme. The measures of comparison used are the network cost, the database cost, and the call set up delay. For all these measures, the proposed scheme performs better than the location management scheme defined in the IS-41 standard. Result comparison also shows that the our scheme performs better than the IS-41 scheme, regardless of CMR(Call-to-Mobility Ratio).

• 한국콘텐츠학회논문지
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• 제7권5호
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• pp.138-145
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• 2007

이동통신망 고도화와 유비쿼터스 센서 네트워크 기술 개발에 따라 상황인지 기반 신규 서비스 모델이 개발되고 있다. 이동통신사업자는 셀 기반의 위치정보를 이용한 친구 찾기 서비스 GPS 위치정보를 이용한 텔레매틱스 서비스 등을 제공하고 있고 최근에는 셀 기반의 위치정보 서비스를 이용한 114 서비스를 제공하고 있다. 본 논문에서는 이동통신망에서 위치정보와 상용자 정보를 이용한 모바일 상황인지 맛집 추천 서비스를 위피 플랫폼을 이용하여 개발하였다. 개발된 모바일 상황인지 맛집 추천 서비스는 이동통신망의 LBS(Location Based Service) 플랫폼으로부터 사용자 위치정보, 유선 웹 서버로부터 계절, 시간, 기상 등의 상황정보, 데이터베이스에 저장된 개인 선호 정보 등을 이용하여 최적의 맛집을 추천한다. 개발된 맛집 추천 서비스는 관광 정보 시스템과 연동하여 텔레매틱스 핵심 서비스로 제공할 수 있다.

• 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.

• Molecules and Cells
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• 제22권1호
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• pp.97-103
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• 2006

Phosphoinositides are critical regulators of ion channel and transporter activity. There are multiple isomers of biologically active phosphoinositides in the plasma membrane and the different lipid species are non-randomly distributed. However, the mechanism by which cells impose selectivity and directionality on lipid movements and so generate a non-random lipid distribution remains unclear. In the present study we investigated which structural elements of phosphoinositides are responsible for their subcellular location and movement. We incubated phosphatidylinositol (PI), phosphatidylinositol 4-monophosphate (PI(4)P) and phosphatidylinositol 4,5-bisphosphate ($PI(4,5)P_2$) with short or long acyl chains in CHO and HEK cells. We show that phosphate number and acyl chain length determine cellular location and translocation movement. In CHO cells, $PI(4,5)P_2$ with a long acyl chain was released into the cytosol easily because of a low partition coefficient whereas long chain PI was released more slowly because of a high partition coefficient. In HEK cells, the cellular location and translocation movement of PI were similar to those of PI in CHO cells, whereas those of $PI(4,5)P_2$ were different; some mechanism restricted the translocation movement of $PI(4,5)P_2$, and this is in good agreement with the extremely low lateral diffusion of $PI(4,5)P_2$. In contrast to the dependence on the number of phosphates of the phospholipid head group of long acyl chain analogs, short acyl chain phospholipids easily undergo translocation movement regardless of cell type and number of phosphates in the lipid headgroup.

• 산업기술연구
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• 제26권B호
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• pp.191-198
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• 2006

In this paper, we focus on a question. Which is better between time-based location update method and movement-based location update method? Or, does any other method combining the two methods show better performance? For the question, we propose a hybrid location update scheme, which integrates the time-based and the movement-based methods. In the proposed scheme, a mobile terminal updates its location after n cell boundary crossing and a time interval of T, or the inverse. We derive an analytical solution for the performance of the hybrid scheme with exponential cell resident time. From the numerical analysis, we conclude that the movement-based method seems to have better performance than the time-based and hybrid methods, that is the optimal costs occur at T=0.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.261-264
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• 2004

We propose a location management with adaptive binding idle lifetime scheme for IP-based wireless network. In our proposed scheme, the binding idle lifetime value is adaptively varied according to user characteristics. The main idea is that the mobile node (MN) does location update (LU) even in idle state. Furthermore a sequential paging scheme is used to reduce the paging cost. The proposed scheme can be used in both cellular network and IP-based 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.

• 한국멀티미디어학회논문지
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• 제6권4호
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• pp.601-609
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• 2003

In wireless mobile networks, the service area is partitioned into several registration areas (RAs). Every RA is associated with a mobility database called Visitor Location Register (VLR). The VLR is used to achieve the location management of the mobile terminals. When a mobile terminal enters a new RA, the VLR stores the current location information of the mobile terminal before serving any mobile services. At that time, if the VLR is full, the registration procedure fails, and the system can not deliver services to the mobile user under the existing cellular technology To resolve this problem, we propose a VLR overflow control scheme considering mobility of mobile users to accomodate incoming users during VLR overflow. The performance of the proposed scheme is evaluated by an analytic model in terms of costs for the location search and the location update, and compared with those of the overflow control scheme proposed by Lin[1].

• 경영과학
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• 제29권1호
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• pp.143-152
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• 2012

Location area planning (LAP) problem is to partition the cellular/mobile network into location areas with the objective of minimizing the total cost in location management. The minimum cost has two components namely location update cost and searching cost. Location update cost is incurred when the user changes itself from one location area to another in the network. The searching cost incurred when a call arrives, the search is done only in the location area to find the user. 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. This partitioning problem is a difficult combinatorial optimization problem. In this paper, we use particle swarm optimization (PSO) to obtain the best/optimal group of cells for 16, 36, 49, and 64 cells network. Experimental studies illustrate that PSO is more efficient and surpasses those of precious studies for these benchmarking problems.

• Advances in Computational Design
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• 제7권2호
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• pp.153-171
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• 2022

The present study aimed to find a way to create forms that can simultaneously meet several architectural requirements by applying generative design methods specifically focused on cellular automata. In other words, it is tried to find various forms of architecture that all have common features. Because of the useful features of cellular automata, we decided to use it to generate various forms, but make a relation between the discrete nature of cellular automata and the continuous nature of architecture, was the major problem of our project. To achieve this goal, three consecutive stages were designed. In the first stage, independent variables including the location of the building, the height of the building, and the building area were considered as the inputs of the model. In the second stage, after locating the building, the building's main shell was designed as a hidden geometry for the cellular automata and then the cellular automata were determined based on this shell. The main result of this research is establishing a logical relationship between the discrete geometry of the cellular automata and the continuous search space such that it creates various optimized forms. Although we specify the site plan of this project at Iran-Tehran, this research can be generalized to various design sites as well as different projects, allowing the architectsto alter the cell dimensions, cell density, etc., based on their opinion and project needs.