Obtain Location Information Research Articles

An Improvement in Maximum Likelihood Location Estimation Algorithm in Sensor Networks

A wireless sensor network contains many sensors that Spread in an environment and gather the information from their vicinity [1]. Wireless sensor networks are tremendously being used in different environments to perform various monitoring tasks such as search, rescue, disaster relief, target tracking and a number of tasks in smart environments. May be the location of sensors are not predefined and given [10]. This feature helps to use them in hazardous or inaccessible places. These sensors after gathering the information from environment and process the data send them to control stations. Later on other parts decide and act based on received information. One of the challenging problems exists in wireless sensor network that is how to obtain location information for sensor nodes present in the network [1].

RSSI Based Indoor Position Monitoring Using WSN in a Home Automation Application

Wireless Sensor Network (WSN) technology has become the key technology to all innovative and novel wireless applications because of its low cost and deployment simplicity. This paper presents a low cost ZigBee based WSN implementation for indoor position monitoring in a home automation application. The real-time knowledge of the location of personnel, assets, and portable instruments can increase home automation control efficiency. Position monitoring otherwise called as location estimation is the process of obtaining location information of a node with respect to a set of known reference positions. Different radio propagation models and localization techniques are discussed. Low cost Digi XBee PRO modules are deployed for location estimation using trilateration method inside a home and mean displacement error value is reported for the same. The application programs have been developed in python language using simple AT commands. The hardware and software framework and related programming are discussed in this paper.

Connectivity-Guaranteed and Obstacle-Adaptive Deployment Schemes for Mobile Sensor Networks

Mobile sensors can relocate and self-deploy into a network. While focusing on the problems of coverage, existing deployment schemes largely oversimplify the conditions for network connectivity: they either assume that the communication range is large enough for sensors in geometric neighborhoods to obtain location information through local communication, or they assume a dense network that remains connected. In addition, an obstacle-free field or full knowledge of the field layout is often assumed. We present new schemes that are not governed by these assumptions, and thus adapt to a wider range of application scenarios. The schemes are designed to maximize sensing coverage and also guarantee connectivity for a network with arbitrary sensor communication/sensing ranges or node densities, at the cost of a small moving distance. The schemes do not need any knowledge of the field layout, which can be irregular and have obstacles/holes of arbitrary shape. Our first scheme is an enhanced form of the traditional virtual-force-based method, which we term the connectivity-preserved virtual force (CPVF) scheme. We show that the localized communication, which is the very reason for its simplicity, results in poor coverage in certain cases. We then describe a floor-based scheme which overcomes the difficulties of CPVF and, as a result, significantly outperforms it and other state-of-the-art approaches. Throughout the paper our conclusions are corroborated by the results from extensive simulations.

Research on Spatial Location Unit Distribution Model in Pervasive Computing

How to obtain location information of an unknown node precisely is a key problem of locating service under ubiquitous computing environment. The paper proposes and proves the theorem of spatial location unit distribution model according to the analysis of the location error produced during location using the polygon location method in the three-dimensional space. On this basis, the location unit selection (LUS) algorithm is proposed by improving on the traditional polygon location algorithm. The simulation results indicate that the location unit distribution model theorem and the LUS algorithm can meet the requirements of a ubiquitous terminal’s real-time location and possess a preferable precision in location.

이동로봇을 위한 IR 랜드마크 기반의 실시간 실내 측위 시스템

The localization is one of the most important issues for mobile robot. This paper describes a novel localization system for the development of a location sensing network. The system comprises wirelessly controlled infrared landmarks and an image sensor which detects the pixel positions of infrared sources. The proposed localization system can operate irrespective of the illumination condition in the indoor environment. We describe the operating principles of the developed localization system and report the performance for mobile robot localization and navigation. The advantage of the developed system lies in its robustness and low cost to obtain location information as well as simplicity of deployment to build a robot location sensing network. Experimental results show that the developed system outperforms the state-of-the-art localization methods.

Three-dimensional optical tomographic imaging of scattering objects in tissue-simulating turbid media using independent component analysis

An information-theory-based approach for the detection and three-dimensional localization of scattering targets embedded in a turbid medium, such as a tumor in the breast, is introduced. The approach uses multisource illumination of the medium, multidetector transillumination signal acquisition, and independent component analysis of the information theory for target detection and localization. The efficacy of the approach is demonstrated by detecting and obtaining location information about scattering targets embedded in human breast tissue-simulating turbid media of thickness 50 times the transport mean-free path.

이동 객체의 과거 및 미래 위치 연산을 위한 데이터 모델

무선 환경에서 시공간 이동 객체들의 위치 정보를 획득할 수 있는 기술들의 발달로 인해, 차량 추적 시스템, 산불 관리 시스템, 디지털 전장 시스템 등과 같은 다양한 응용 시스템들이 개발되고 있다. 이와 같은 응용에서는 이동 객체의 연속적인 변화 과정을 표현하고, 처리할 수 있는 데이터 모델이 필요하다. 그러나 관계형 모델을 이용하여 이동 객체를 표현할 경우 매 시간 마다 변경된 모든 정보를 저장할 수 없는 문제점이 발생된다. 또한 기존의 이동 객체 데이터 모델에서는 질의 시점을 데이터베이스로 관리되는 과거 시간이나 현재로부터 가까운 미래 시간으로 제한하는 단점이 있다. 따라서 이 논문에서는 모양 변화 처리 기법과 과거와 미래의 위치 추정 함수를 사용함으로써 이동 점 및 이동 영역 객체의 연속적인 움직임을 표현하고 모든 질의 시점에서의 연산을 저리 할 수 있는 이동 객체 데이터 모델을 제안한다 아울러 제안 모델을 산불관리 시스템에 적용 및 구현한 결과를 통해 타당성을 평가한다. In the wireless environment, according to the development of technology, which is able to obtain location information of spatiotemporal moving object, the various application systems are developed such as vehicle tracking system, forest fire management system and digital battle field system. These application systems need the data model, which is able to represent and process the continuous change of moving object. However, if moving objects are expressed by a relational model, there is a problem which is not able to store all location information that changed per every time. Also, existing data models of moving object have a week point, which constrain the query time to the time that is managed in the database such as past or current and near future. Therefore, in this paper, we propose a data model, which is able to not only express the continuous movement of moving point and moving region but also process the operation at all query time by using shape-change process and location determination functions for past and future. In addition, we apply the proposed model to forest fire management system and evaluate the validity through the implementation result.

Look, Ma, My Homepage is Mobile!

Much of the ongoing research in ubiquitous computing has concentrated on providing context information, e.g. location information, to the level of services and applications. Typically, mobile clients obtain location information from their environment which is used to provide “locally optimal” services. In contrast, it may be of interest to obtain information about the current context a mobile user or device is in, from a client somewhere on the Web, i.e. to use the mobile device as an information provider for Internet clients. As an instance of such services we propose the metaphor of a “location-aware” Web homepage of mobile users providing information about, e.g. the current location a mobile user is at. Requesting this homepage can be as easy as typing a URL containing the mobile user’s phone number such as http://mhp.net/p49123456789 in an off-the-shelf browser. The homepage is dynamically constructed as Web users access it and it can be configured in various ways that are controlled by the mobile user. We present the architecture and implementation and discuss issues around this example of “inverse” ubiquitous computing.