Interactive applications of personal situation-aware assistants

Ultraportable mobile computers provide electronic assistance for environments and usage situations, where computer support up to now has not been feasible. For the first time, a true physical and cognitive integration of computer support into the everyday business of the real-world becomes possible, as envisioned in Mark Weiser's concept of “ubiquitous computing” (Weiser, Communication of the ICM 1993, 36 (12): 75–85). However, although Handheld-PC, etc. today; already support a good deal of personal information management and basic access to distributed multimedia information services such as the World-Wide Web, they are still surprisingly difficult to use in “full action”. Specifically, lengthy interaction sequences and the inability to find quickly that important piece of information which is embedded somewhere in the machine, makes using those devices sometimes a very disappointing experience. In this, paper, we outline a new approach to realizing an easy-to-use personal digital assistant systems, based on the concept of Situation Awareness. Using knowledge about task structures, situation dependencies, and task contexts, our concept allows a mobile assistant to proactively provide the right information at the right time and the right place, without intruding upon the users primary task: interacting with reality.     

面向移动互联网终端的安全态势感知研究

本文在分析移动互联网终端的安全态势基础上,采用面向对象方法设计了移动终端安全态势模型,采用UML类图对终端态势指标进行描述。设计了一个态势数据感知框架,研究并实现了移动终端态势数据的远程获取。     

Experiences in developing mobile applications using the Apricot Agent Platform

The trend of increasing mobile services has set a new challenge for service providers: how to develop more advanced and user-friendly, context-aware and personalized mobile services for the users. Apricot Agent Platform is an agent-based software platform designed for developing context-aware and personalized mobile services. Apricot Agent Platform supports the development of user-friendly mobile services by providing tools for combining various mobile and Internet-based services. Apricot agent architecture consists of an agent platform, agents and agent containers. For the developers of mobile services, it provides built-in functionality and communication mechanism. Furthermore, this paper describes four demonstrators that are built up on the Apricot Agent Platform to evaluate the usability and efficiency of the platform in the processes of building mobile services. The outcome of the evaluation indicates relatively promising results and the further target for development is revealed.     

移动协同感知研究综述

移动感知网在军事、工业、医疗、交通、商业上运用极其广泛.为了进一步提高移动感知网的性能,更好地协同节点的移动感知行为,本文提出了移动协同感知技术.首先介绍了国内外近年来有关移动协同感知技术的发展情况和关键技术,包括移动协同感知模型、移动协同感知中间件、移动协同感知相关技术,然后概括归纳了技术特点,最后总结了移动协同感知技术的研究意义和发展趋势.     

Reduction of the broadcast redundancy by location awareness in mobile ad hoc networks

In this paper, a reachability-guaranteed approach for reducing broadcast storms in MANET is proposed. The approach is based on location awareness of each node, which means each node in the network needs to equip the positioning device like GPS and exchanges location information in the HELLO message with its neighbors. Three mechanisms are included in the proposed approach: Relay Set (RS), Neighbor Coverage (NC), and Transmission Order (TO). RS is a sender-based mechanism in which the sending node of the broadcast message determines the relay set of its neighbors for rebroadcast according to the radio coverage of the neighbors. The idea of the received-based NC is: a node receiving a broadcast message does not have to rebroadcast the message if all its neighbors have received the same message. TO mechanism requires a farther neighbor node away from the sending node to rebroadcast the message earlier than closer nodes so that a closer node may have more chances to save the rebroadcast. Simulation results have shown that the proposed approach ‘RS+NC+TO’ has a better performance than existing solutions like threshold-based schemes and angle-based scheme in terms of 100% reachability, more saved rebroadcast, and shorter average latency.     

Network-aware support for mobile distributed teams

An experiment evaluated network-aware support to increase understanding of the factors that are important for successful teamwork in mobile geographically dispersed teams of first responders. Participants performed a simulated search and rescue team task and were equipped with a digitized map and real-time situation updates on the location of other participants in a simulated disaster area. The connection to a server, however, was made deliberately error-prone, leading to occasional losses of network connections. Consequently, participants were not provided with real-time situation updates. To deal with this problem we equipped team members with a network-aware application that signaled network loss to them and adapted the graphical representation of the location of fellow team members accordingly to the quality of location information present. The experiment revealed that presenting complete and reliable geospatial information improves teamwork. Teams connected to a server over a fast and reliable link showed superior performance over teams with no network connection whatsoever to a server. The present study failed, however, to demonstrate the added value of network-aware support when teams had to collaborate in the presence of an unreliable communications infrastructure. Although participants indicated a slight preference for the network-aware application over a condition without support signaling network loss, no differences were observed in team process and outcome measures.     

Social functions of location in mobile telephony

Location appears to be one of the most important aspects of context in mobile communication. It is a complex piece of information involving several levels of detail. Location intertwines with other relevant aspects of context: the parties’ present activity, relative time and identities. The analysis of mobile conversations provides insights into the functions of “location” for mobile users. Most mobile calls involve a sequence in which location is reported. Location is made relevant by the parties’ activities. Location telling takes place in five different activity contexts during mobile calls. Location may be an index of interactional availability, a precursor for mutual activity, part of an ongoing activity, or it may bear emergent relevance for the activity or be presented as a social fact. Typically, joint activities make relevant spatio-temporal location such as distance in minutes from the meeting point via the vehicle used. For users, location does not appear to be relevant in purely geographical terms.     

Continuous awareness: A visual mobile approach

Facing the challenges of global distribution in software development, Continuous Coordination constitutes a new coordination paradigm that helps break the communication barriers in distributed teams by providing awareness information and integrating heterogeneous tools. Continuous Awareness is an extension of Continuous Coordination emphasizing continuous awareness support across space and time. Traditional desktop-based approaches are insufficient for the requirements of continuous awareness. Team Radar Mobile takes a visual mobile approach to awareness by extending the visualization of awareness information on desktop platforms to mobile platforms. The concept of continuous awareness and its implementation on multiple platforms are discussed. An experiment has evaluated the visual mobile approach to continuous awareness, and found visualization express awareness information more efficiently than the non-visual approach. Our work also provides experience on mobile visualization.     

A two-tier test approach to developing location-aware mobile learning systems for natural science courses

The advancement of wireless and mobile technologies has enabled students to learn in an environment that combines learning resources from both the real world and the digital world. Although such an approach has been recognized as being innovative and important, several problems have been revealed in practical learning activities. One major problem is owing to the lack of proper learning strategies or tools for assisting the students to acquire knowledge in such a complex learning scenario. Students might feel excited or engaged when using the mobile devices to learn in the real context; nevertheless, their learning achievements could be disappointing. To deal with this problem, this study presents a mobile learning system that employs Radio Frequency Identification (RFID) technology to detect and examine real-world learning behaviors of students. This study also utilizes each student’s responses from a two-tier test (i.e., multiple-choice questions in a two-level format) to provide personalized learning guidance (called two-tier test guiding, T³G). The experimental results from a natural science course of an elementary school show that this innovative approach is able to improve the learning achievements of students as well as enhance their learning motivation.     

移动云计算中的上下文相关身份认证

上下文相关信息,例如可操作的、用户个人的、空间的、环境的信息能够为用户提供他们确实需要而没有明确表示的服务。利用上下文内容相关的方法分析移动设备提供的用户通话记录、日程表、GPS和用户安装的应用。在收集这几方面信息之后,加以考虑时间和地点的因素,使整个认证过程更有可靠性。提出在移动云计算背景下的上下文相关身份认证框架,并详细描述框架的各个组件及决策器的算法模型和通信协议部分,使用户能够更加方便、安全地使用移动云。     

A lightweight and distributed middleware to provide presence awareness in mobile ubiquitous systems

Several researchers have identified the need to count on presence awareness in ubiquitous systems that support mobile activities, particularly when these systems are used to perform loosely-coupled mobile work. In such a work style, mobile users conduct face-to-face on-demand interactions, therefore counting on awareness information about the position and availability of potential collaborators becomes mandatory for these applications. Most proposed solutions that provide user presence awareness involve centralized components, have reusability limitations, or simply address a part of that service. This article presents a lightweight and fully distributed middleware named Moware, which allows developers to embed presence awareness services in mobile ubiquitous systems in a simple way. The article also describes the Moware architecture, its main components and strategies used to deal with several aspects of the presence awareness support. These design strategies can be reused by software designers to provide presence awareness capabilities into middleware and specific software applications. Moware services were embedded in a mobile ubiquitous system that supports inspectors during the construction inspection process. The preliminary results indicate that the middleware was easy to use for developers, and its services were useful for the end-users.     

Bandwidth determined transmoding through fuzzy logic in mobile intelligent multimedia presentation systems

Mobile intelligent multimedia presentation systems are subject to various resource constraints including mobile network characteristics, mobile device capabilities and user preferences. Those presentation systems which incorporate remote multimedia content accessed across HTTP (Hyper Text Transfer Protocol) or RTP (Real Time Transfer Protocol) protocols are particularly reliant on the capabilities of the connecting mobile network (i.e. minimum, average and maximum bandwidth) and in particular on the real-time constraints (i.e. currently available bandwidth, packet loss, bit error rate, latency) which prevail during actual content transmission. One approach to address this is to scale content, thus reducing its datarate requirement, although this technique is inherently limited by the lowest acceptable quality of that media element. Alternatively, content can be converted from one modality to another with a lower resource requirement. TeleMorph, a cross-modality adaptation control platform is detailed here. Initially a brief introduction to Intelligent Multimedia and to Mobile Intelligent Multimedia is given, and key systems discussed. The main premise of TeleMorph is that cross-modality adaptations in mobile presentation systems must be controlled in a manner which gives primary consideration to bandwidth fluctuations as well as the constraints listed above. The current prototype of TeleMorph, which uses a fuzzy inference system to control cross-modality adaptations between video and audio, is described. Particular focus is given to the fuzzy inputs, fuzzy control rules and fuzzy outputs which have been utilised in decision making. TeleTuras, a tourist information application which has been implemented as a testbed for TeleMorph, gives promising evaluation results based on multimedia and bandwidth specific test scenarios. TeleMorph is related to other approaches in the area of Mobile Intelligent Multimedia Presentation Systems. TeleMorph differs from other approaches in that it focuses specifically on the challenges posed by controlling bandwidth determined cross-modality adaptations in a mobile network environment. Future work on TeleMorph’s output presentation composition will incorporate images and text also, thus allowing for extended adaptation between video, audio, images and text, as well as multimodal combinations of these media elements.     

Refining visualization reference model for context information

Context-awareness can be used to decrease the need for interaction with a mobile device. This is increasingly important since the functionality of mobile devices and personal digital assistants gets more and more complex while the input and output capabilities remain restricted. An important aspect of context-awareness is to present the current context to the user. We propose a model for visualizing contextual information on the mobile terminal screen. The model is a refinement of a well-known visualization reference model; it takes into account the specific characteristics of mobile use and context information. We present the design of the model in detail, and discuss its applicability for a variety of contexts and tasks by providing a full-fledged use case.     

Automated context aggregation and file annotation for PAN-based computing

This paper presents a method for automatically annotating files created on portable devices with contextual metadata. We achieve this through the combination of two system components. One is a context dissemination mechanism which allows devices in a personal area network (PAN) to maintain a shared aggregate contextual perception. The other is a storage management system that uses such context information to automatically decorate files created on personal devices with annotations. As a result, the user is able to flexibly browse and lookup files that were generated on the move, based on the contextual situation at the time of their creation. What is equally important is that the user is relieved from the cumbersome task of having to manually provide annotations in an explicit fashion. This is especially valuable when generating files on the move, using U/I-restricted portable devices.

Comparison of efficient random walk strategies for wireless multi-hop networks

Wireless multi-hop networks have drawn great attention from research and business communities, since they suit well diverse application scenarios, such as environmental monitoring, military support in hostile environments and emergency applications. However, this challenging communication paradigm requires solutions able to fit specific requirements in terms of resource constrains, node mobility and quality of service. Random Walks (RWs) are probabilistic approaches to perform distributed operations, such as data search and retrieval. They are effective and have relatively small overhead compared to classic schemes, such as flooding. To further improve performance of RWs, hybrid solutions may be employed. Such strategies increase system performance at the cost of additional energy consumption. In this work, we propose two novel schemes that exploit local topological information in order to increase the hybrid RW protocols performance. Through simulations, we compare hybrid protocols with a traditional RW solution, studying their performance in static and mobile scenarios. An analysis of the trade-off between the number of node revisits and energy consumption allows to identify the more fitting protocols for different application scenarios in wireless multi-hop networks. Advantages and drawbacks of different RW strategies are highlighted, along with research challenges that need to be investigated in the future.     

记忆计算:概念、特性及研究进展

随着信息技术的发展,尤其是移动互联网与物联网的发展,有关个人工作和生活的数据呈指数型增长。这些海量的数据中蕴含着丰富而有价值的个人信息,如何从这些数据中挖掘出有价值的信息成为当前信息领域的重要问题。针对该问题,介绍了普适计算领域新兴起的研究主题——记忆计算。记忆计算旨在通过各种带感知和计算功能的设备,比如智能手机、可穿戴设备等,实时感知和捕获用户线上线下活动的数据,分析并挖掘其内在价值,进而组织和管理有意义的记忆数据,实现基于情境的记忆数据呈现,以辅助个体记忆,支持社群交流与协作。讨论了基于移动情境感知的记忆计算的概念、特性、系统模型以及当前研究的关键技术与挑战,综述了记忆计算在生活日志、记忆提醒、往事回忆和群体记忆分享等方面的研究进展,并对其未来发展进行了展望。     

Bridging the gap between students and computers: supporting activity awareness for network collaborative learning with GSM network

The internet has been widely used to promote collaborative learning among students. However, students do not always have access to the system, leading to doubt in the interaction among the students, and reducing the effectiveness of collaborative learning, since the web-based collaborative learning environment relies entirely on the availability of computers and the internet. A web-based collaborative learning scheme based on activity awareness carried out through mobile phones is proposed herein. The proposed mechanism automatically sends SMS messages on a GSM network, based on student identity and learning activity, making the student aware of the collaborative learning context, and further improving the student's learning. A web-based collaborative learning activity was implemented in a Taiwan undergraduate class to examine the proposed scheme. Experiments demonstrated that awareness of the collaborative learning context through mobile phones significantly increased student participation in learning activity and improving student learning performance.     

Bayesian approach to sensor-based context awareness

The usability of a mobile device and services can be enhanced by context awareness. The aim of this experiment was to expand the set of generally recognizable constituents of context concerning personal mobile device usage. Naive Bayesian networks were applied to classify the contexts of a mobile device user in her normal daily activities. The distinguishing feature of this experiment in comparison to earlier context recognition research is the use of a naive Bayes framework, and an extensive set of audio features derived partly from the algorithms of the upcoming MPEG-7 standard. The classification was based mainly on audio features measured in a home scenario. The classification results indicate that with a resolution of one second in segments of 5–30 seconds, situations can be extracted fairly well, but most of the contexts are likely to be valid only in a restricted scenario. Naive Bayes framework is feasible for context recognition. In real world conditions, the recognition accuracy using leave-one-out cross validation was 87% of true positives and 95% of true negatives, averaged over nine eight-minute scenarios containing 17 segments of different lengths and nine different contexts. Respectively, the reference accuracies measured by testing with training data were 88% and 95%, suggesting that the model was capable of covering the variability introduced in the data on purpose. Reference recognition accuracy in controlled conditions was 96% and 100%, respectively. However, from the applicability viewpoint, generalization remains a problem, as from a wider perspective almost any feature may refer to many possible real world situations.     

Comparing the effects of mobile computers and traditional approaches in environmental education

Environmental education and computers? That was traditionally seen as an antagonism. But environmental educators who compete for attention and face new challenges in an age of mobile devices, have begun to explore the opportunities that mobile computers may offer in supporting environmental learning experiences. This study investigates the impact of a mobile guide system on different parameters of environmental literacy in comparison to traditional instruments of environmental education (i.e. brochure, human guide). In a field experiment at a floodplain conservation site, 185 school children and 76 adults participated in a guided tour using different media. Despite the novelty of mobile devices and usability issues associated with the prototype mobile nature guide, participants using the computer-assisted medium achieved similar results concerning environmental literacy components. The computer as mobile guide can lead to an increase in environmental knowledge and in case of the children it can increase their motivation to engage in environmental education activities.     

Acoustic environment as an indicator of social and physical context

Acoustic environments provide many valuable cues for context-aware computing applications. From the acoustic environment we can infer the types of activity, communication modes and other actors involved in the activity. Environmental or background noise can be classified with a high degree of accuracy using recordings from microphones commonly found in PDAs and other consumer devices. We describe an acoustic environment recognition system incorporating an adaptive learning mechanism and its use in a noise tracker. We show how this information is exploited in a mobile context framework. To illustrate our approach we describe a context-aware multimodal weather forecasting service, which accepts spoken or written queries and presents forecast information in several forms, including email, voice and sign languages.