基于移动代理的上下文感知系统研究

上下文表是用上下文信息描述实体状态,原子上下文感知反应则说明了系统根据当前上下文和历史上下文做出合适的响应.基于以上两个概念设计了上下文感知移动代理、系统代理和上下文感知移动代理服务环境,目的是解决普适计算系统需要自动适应用户行为及环境变化的问题.首先使用历史上下文与当前上下文提取上下文表达式,根据该表达式在上下文反应容器中匹配对应的操作,然后由系统代理执行该操作,为用户提供任务相关的服务或者信息.其次根据原子上下文感知提出若干实例,并由上下文感知演算验证,同时指出上下文感知演算的不足.最后,用染色Petri网对一个实例场景仿真,证明了系统的可行性.     

无线传感器网络追踪系统中的一种高效位置更新机制

在传统的追踪系统中,移动节点需要周期性地向服务器汇报其位置信息.但是随着移动节点数目的增加,这种方式会导致很高的丢包率和快速的能量消耗.同时,在实际的追踪应用中,观察到节点之间距离通常很接近.因此,如果选出部分节点作为代理,由代理节点周期性地汇报位置信息能够极大地减少网络中的消息复杂度和能量消耗.基于此想法,提出了无线传感器网络追踪系统中的一种高效位置更新机制(LUM).在该机制中,移动节点只通过远程代理和近程代理这两种代理节点来更新位置信息.为验证该机制的性能,在真实的实验室环境中布置一个包含38个Micaz节点的原型系统.实验结果显示,与传统方法相比,LUM能够平均减少45%的消息发送和48%的能量消耗.     

移动代理应用中上下文相关的客观协调

移动代理之间需要进行交互合作才能完成系统任务,每个移动代理也需要与它运行所在的移动代理环境进行交互。文章提出了一种在移动代理应用系统中的上下文相关的客观协调模型,适合移动代理系统中移动代理之间的交互和移动代理与移动代理环境之间的交互,它把全局的耦合交互转变成本地独立的元组空间交互,用可编程的元组空间解决由代理移动引起的上下文相关协调问题,而且环境相关的协调策略和应用相关的协调策略可以集成到可编程的元组空间中。     

基于位置服务的研究综述

基于位置的服务是指移动终端利用各种定位技术获得当前位置信息,再通过无线通信将这些信息传输给服务提供商,服务提供商根据用户的位置信息以及用户的上下文信息提供个性化的服务。对位置服务按照不同的方面进行了分类,然后分析了基于位置服务中的关键技术,包括定位、信息传输以及位置索引,接着总结了基于位置服务的典型应用,最后指出了存在的一些问题。     

Web资源地理位置分类与检测

检测Web资源地理位置信息是建立各种基于地理位置的Web应用的关键问题。本文在调研大量地理位置应用需求的基础上提出将Web资源地理位置区分为实体位置、内容位置和服务位置,并针对这三种不同的位置定义给出了一套自成体系的学习与检测架构。在该系统中,每种位置定义的计算只考虑与其相关的地理信息源和相适应的检测方法。基于
大规模真实Web数据集上的实验结果证明了所提出的分类与检测机制的合理性和有效性。     

基于位置信息的流式移动应用推送系统的研究

目前与位置相关的移动应用越来越多,传统应用分发模式中,用户需要手动对应用进行搜索、下载、安装以及卸载,不利于提升用户使用应用服务的体验。设计并实现了基于位置信息的流式移动应用推送系统,该系统中服务器利用移动终端位置信息将相关应用解析、安装,并推送到移动终端显示,移动终端根据用户的选择从服务器流式加载应用。该系统使得用户在切换位置时,不用下载、安装即可使用和当前位置相关的应用服务。实验表明,和传统应用分发模式相比,在3G网络环境下可以减少64.37%的应用获取时延,在4G网络环境下可以减少74.49%的应用获取时延。     

基于云计算的LBS应用研究

伴随着移动互联网的发展,基于位置的服务LBS(location Based Service)服务应用市场爆发式发展。随着大数据时代的到来,人们的位置信息数据规模巨大,如何利用云计算平台处理LBS应用及相关服务成为人们下一步的研究重点。本项目基于对LBS在国内外的应用的研究,讨论云计算平台在LBS相关服务中实现方式;并基于高德地图位置云服务,构建基于Android黄冈旅游手机客户端系统。     

基于移动代理的入侵检测系统关键技术研究

移动代理作为一种先进的软件技术,可有效解决入侵检测系统分布式天然特性所带来的诸多问题。本文提出了一种基于移动代理的入侵检测系统模型并实现了其原型系统,深入阐述了在入侵检测系统中应用移动代理技术所需要解决的关键问题。     

一种智能选择多维位置数据的移动定位体系结构

通过动态获取和发送移动终端相关的位置信息，下一代移动通信网络（3G／4G）能提供一个较广范围的新应用。移动网络现在能越来越准确地确定终端的位置，使得时移动终端提供移动定位服务（MLS）成为可能。提出了一个与定位服务相关的层次模型和一种支持互联网及定位导航的定位服务体系结构，移动用户可以根据其当前的需要选择不同类型的位置数据输出。     

一种智能手机上下文信息获取的代价模型及其应用

随着信息技术的发展和应用需求的增长,智能手机中嵌入了各种传感器和网络接口,它们是获取上下文信息,进而构建智能型移动应用的关键。尽管在智能手机中获取上下文信息的代价很大,但是这种代价却通常被移动应用开发者所忽视。提出了一个上下文信息获取的代价模型,它能对上下文信息获取的代价进行度量。设计并实现了一个上下文信息获取代价模型的测量工具CRCTest,并对Android智能手机的代价模型进行了测量。基于测量得到的Android平台上下文信息获取的代价模型实现了一个应用实例,通过对比两种位置上下文信息生成方式的代价,说明了基于代价模型优化设计上下文获取的可行性。     

A hybrid positioning system for technology‐independent location‐aware computing

Location‐aware computing is a form of context‐aware mobile computing that refers to the ability of providing users with services that depend on their position. Locating the user terminal, often called positioning, is essential in this form of computing. Towards this aim, several technologies exist, ranging from personal area networking, to indoor, outdoor, and up to geographic area systems. Developers of location‐aware software applications have to face with a number of design choices, that typically depend on the chosen technology. This work addresses the problem of easing the development of pull location‐aware applications, by allowing uniform access to multiple heterogeneous positioning systems. Towards this aim, the paper proposes an approach to structure location‐aware mobile computing systems in a way independent of positioning technologies. The approach consists in structuring the system into a layered architecture, that provides application developers with a standard Java Application Programming Interface (JSR‐179 API), and encapsulates location data management and technology‐specific positioning subsystems into lower layers with clear interfaces. In order to demonstrate the proposed approach we present the development of HyLocSys. It is an open hybrid software architecture designed to support indoor/outdoor applications, which allows the uniform (combined or separate) use of several positioning technologies. HyLocSys uses a hybrid data model, which allows the integration of different location information representations (using symbolic and geometric coordinates). Moreover, it allows support to handset‐ and infrastructure‐based positioning approaches while respecting the privacy of the user. The paper presents a prototypal implementation of HyLocSys for heterogeneous scenarios. It has been implemented and tested on several platforms and mobile devices. Copyright © 2009 John Wiley & Sons, Ltd.     

Hybrid indoor and outdoor location services for new generation mobile terminals

In the last years, an increasing interest in location services characterized the market of mobile ubiquitous devices (smartphones, handhelds, etc.). Several technologies and solutions have been developed to determine the position of mobile devices in their operating space, each with its specific degree of precision and accuracy. In this scenario, the ideal location service should be able of tracking the mobile terminal in any place it moves to, both indoors and outdoors. However, while outdoor location services have already achieved a satisfactory degree of technological maturity and effectiveness, a really ubiquitous location service that works satisfactorily in both indoor and outdoor scenarios is not yet available. In order to cope with the above challenge, this work proposes a hybrid location approach designed to choose and switch among multiple positioning technologies supported by the mobile device and available in the surrounding environment, in a dynamic and transparent way during the user movement. It combines signal strength–based fingerprinting techniques for indoor positioning together with traditional GPS-based positioning for the outdoor localization and performs opportunistic technology switching according to a count-and-threshold mechanism. The resulting solution is able to leverage the different features of the wireless networks and of the global positioning technologies, in order to provide ubiquitous location services across indoor and outdoor scenarios, as well as to minimize power consumption of the mobile device.     

Ein UML-basiertes Framework zur Modellierung ubiquitärer Web-Anwendungen

Electronic commerce (e-commerce) and mobile commerce (m-commerce) have dramatically boosted the demand for services which enable ubiquitous access. Ubiquity offers opportunities in terms of time aware, location aware, device aware, and personalised services. Development of ubiquitous Web applications, however, turns out to be rather complex and thus requires appropriate methodological support. Existing methods for modelling Web applications only partially match the requirements resulting from their ubiquitous nature.This article aims at filling this gap by presenting a UML based framework for modelling ubiquitous Web applications, focussing on issues of adaptation modelling. It encompasses both, context modelling by providing a physical and a logical context model, and modelling the adaptation process per se. The latter is realised in terms of a rule model enabling monitoring of context changes and activation of corresponding adaptation operations. The separation of a Web application in a stable and context independent part on the one hand and a variable and context dependent part on the other hand supports reusability and locality of change.     

The personalized context‐aware mobile advertisement system using a novel approaching detection method over cellular networks

With the rapid development of smartphones and personal tablet computers, it brings a greatly growing rate of ubiquitous applications for location‐based services (LBS). One famous LBS is the mobile advertisement. A mobile advertisement system brings benefits and opportunities among users, service providers, and advertisers. In this paper, we propose a personalized context‐aware mobile advertisement system (PCA‐MAS) over cellular networks, which contains two new techniques called (i) approaching detection method (ADM) and (ii) context‐aware ad targeting method (CAADTM). ADM can find some point of interests that a user is approaching; CAADTM pushes advertisements that satisfy user's requirement based on the user's context, that is, user's profile, current time, current position, and so on. Our experimental results show that (i) ADM has the good hit rate to determine those point of interests that a user is approaching within the 150‐m radius of the approaching range, and (ii) CAADTM has the good hit rate of finding appropriate advertisements that a user prefers through the favorite content table filtering, the annoying content table filtering, and the advertisement clicking feedback. Copyright © 2013 John Wiley & Sons, Ltd.     

An indoor location tracking based on mobile RFID for smart exhibition service

Recently, various smart application services have been developed using GPS (Global Positioning System), RFID (Radio Frequency IDentification) and sensor networks. The GPS has been successfully applied for outdoor location tracking by many applications, but it might still be insufficient in an indoor environment where GPS signals are often severely obstructed. The RFID technology has been utilized to play an important role in location tracking for indoor smart applications. Therefore, in this paper, we present the scenario and architecture of an indoor location tracking service for things or space in an exhibition environment based on mobile RFID. The RFID tags of things or spaces are identified as the locations of point being passed and we obtain the spatial data from the tags using mobile RFID readers, Web server and Database server. We have designed and implemented the prototype of location tracking system for exhibition scenario using Microsoft .NET framework. Additionally, we have verified the functionality of this system so various other indoor smart services may be provided using the proposed system.     

Providing location based information/advertising for existing mobile phone users

In the emerging world of m-commerce potential users consistently cite location based information as one of the emergent services that they would most likely utilise. However, solutions for obtaining the specific location of a mobile user predominately rely on the provision of additional hardware and/or software within either the mobile phone or system infrastructure. Further, these techniques are often inappropriate for indoor and highly urban environments, where they are often most useful, as the line of sight to the location measurement unit is often obscured resulting in inaccurate and unreliable positional information. In this paper we present a system that can be used with any current mobile phone system to provide location based information/advertisements to any mobile phone, equipped with Bluetooth technology, without any necessity of installing client side software. The system is readily deployable and can be used to provide systems such as location based information for tourist in cities or museums or indeed location based advertisements.     

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 ashttp://mhp.net/+49123456789 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.     

iConAwa - An intelligent context-aware system

Context-awareness becomes an increasingly important concept in the development of mobile and ubiquitous systems. Applications and services, which run in these kinds of highly dynamic environments, should be aware of and adapt to their contexts. Context-aware applications improve and enrich people’s interactions with devices, computers and other people.In this paper, design and development of iConAwa, which is an intelligent context-aware multi-agent system proactively providing mobile users with context-aware information and services, is described. In iConAwa, mobile users can get information and services about nearby resources (attraction points) according to their context and also communicate with each other by exchanging messages. Context and point of interest ontologies are developed in OWL. Context and points of interest are modelled in a flexible and extensible way by the developed ontology models. Knowledge sharing and knowledge reuse are also provided by using these ontology models. iConAwa makes use of rule-based context reasoning which provides derivation of high level implicit context from low level explicit context. With this approach context reasoning is decoupled from the source code of the system. JADE agent development framework is used to develop the agents and Jena semantic web framework is used to manipulate ontologies and for rule based reasoning.     

Examining Factors Influencing the Disruptiveness of Notifications in a Mobile Museum Context

Ubiquitous computing environments continuously infer our context and proactively offer us context aware services and information, suggested by notifications on our mobile devices. However, notifications come with a cost. They may interrupt the user in the current task and be annoying in the wrong context. The challenge becomes how to notify the user about the availability of relevant services while minimizing the level of disruptiveness. Thus, an understanding of what affects the subjective perception of the disruptiveness of the notification is needed. As yet, most of the research on disruptiveness of notifications focused on stationary, task-oriented environments. In this study, we examine the effect of notifications in a special leisure scenario—a museum visit. In two user studies conducted in a museum setting, participants used a context-aware mobile museum guide to receive information on various museum exhibits while periodically receiving notifications. We examined how the user’s activity, the modality of the notification, and the message content affected the perceived level of disruption that the notifications created. We discuss our results in light of existing work in the desktop and mobile domains and provide a framework and recommendations for designing notifications for a mobile museum guide system.     

On the Design and Prototype Implementation of a Multimodal Situation Aware System

In this paper we describe the design concepts and prototype implementation of a situation aware ubiquitous computing system using multiple modalities such as National Marine Electronics Association (NMEA) data from global positioning system (GPS) receivers, text, speech, environmental audio, and handwriting inputs. While most mobile and communication devices know where and who they are, by accessing context information primarily in the form of location, time stamps, and user identity, the concept of sharing of this information in a reliable and intelligent fashion is crucial in many scenarios. A framework which takes the concept of context aware computing to the level of situation aware computing by intelligent information exchange between context aware devices is designed and implemented in this work. Four sensual modes of contextual information like text, speech, environmental audio, and handwriting are augmented to conventional contextual information sources like location from GPS, user identity based on IP addresses (IPA), and time stamps. Each device derives its context not necessarily using the same criteria or parameters but by employing selective fusion and fission of multiple modalities. The processing of each individual modality takes place at the client device followed by the summarization of context as a text file. Exchange of dynamic context information between devices is enabled in real time to create multimodal situation aware devices. A central repository of all user context profiles is also created to enable self-learning devices in the future. Based on the results of simulated situations and real field deployments it is shown that the use of multiple modalities like speech, environmental audio, and handwriting inputs along with conventional modalities can create devices with enhanced situational awareness.