Trust-based security in pervasive computing environments

Traditionally, stand-alone computers and small networks rely on user authentication and access control to provide security. These physical methods use system-based controls to verify the identity of a person or process, explicitly enabling or restricting the ability to use, change, or view a computer resource. However, these strategies are inadequate for the increased flexibility that distributed networks such as the Internet and pervasive computing environments require because such systems lack central control and their users are not all predetermined. Mobile users expect to access locally hosted resources and services anytime and anywhere, leading to serious security risks and access control problems. We propose a solution based on trust management that involves developing a security policy, assigning credentials to entities, verifying that the credentials fulfill the policy, delegating trust to third parties, and reasoning about users' access rights. This architecture is generally applicable to distributed systems but geared toward pervasive computing environments     

Situation-based testing for pervasive computing environments

A challenge for designing pervasive computing systems, particularly for indoor sensor-rich environments, is the complexity of causal relationships between contextual inputs, exhibited system behaviour, and overall appropriateness of resulting outcomes. Two key challenges faced by designers when testing these systems lie in the difficulty of monitoring the deployment environment for inappropriate outcomes and subsequently tracing the physical and digital causal factors leading to specific situations. This paper presents InSitu, a situation-based testing approach that applies generalised situation specifications to a global representation of simulated environment state to detect instances of specified situations. An access control case study demonstrates the modelling capabilities of InSitu and notes the importance of the overlap, exclusivity, and subsumption relationships between situation specifications in order to achieve informative results.     

Understanding identity exposure in pervasive computing environments

Various miniaturized computing devices that store our identity information are emerging rapidly and are likely to become ubiquitous in the future. They allow private information to be exposed and accessed easily via wireless networks. When identity and context information is gathered by pervasive computing devices, personal privacy might be sacrificed to a greater extent than ever before. People whose information is targeted may have different privacy protection skills, awareness, and privacy preferences. In this research, we studied the following issues and their relations: (a) identity information that people think is important to keep private; (b) actions that people claim to take to protect their identities and privacy; (c) privacy concerns; (d) how people expose their identity information in pervasive computing environments; and (e) how our RationalExposure model can help minimize unnecessary identity exposure. We conducted the research in three stages, a comprehensive survey and two in-lab experiments. We built a simulated pervasive computing shopping system, called InfoSource. It consisted of two applications and our RationalExposure model. Our data show that identity exposure decisions depended on participants’ attitudes about maintaining privacy, but did not depend on participants’ concerns or security actions that they claimed to have taken. Our RationalExposure model did help the participants reduce unnecessary disclosures.     

On data management in pervasive computing environments

This paper presents a framework to address new data management challenges introduced by data-intensive, pervasive computing environments. These challenges include a spatio-temporal variation of data and data source availability, lack of a global catalog and schema, and no guarantee of reconnection among peers due to the serendipitous nature of the environment. An important aspect of our solution is to treat devices as semiautonomous peers guided in their interactions by profiles and context. The profiles are grounded in a semantically rich language and represent information about users, devices, and data described in terms of "beliefs," "desires," and "intentions." We present a prototype implementation of this framework over combined Bluetooth and Ad Hoc 802.11 networks and present experimental and simulation results that validate our approach and measure system performance.     

Context-driven personalized service discovery in pervasive environments

Pervasive environments are characterized by a large number of embedded devices offering their services to the user. Which of the available services are of most interest to the user considerably depends on the user’s current context. User context is often rich and very dynamic; making an explicit, user-driven discovery of services impractical. Users in such environments would instead like to be continuously informed about services relevant to them. Implicit discovery requests triggered by changes in the context are therefore prevalent. This paper proposes a proactive service discovery approach for pervasive environments addressing these implicit requests. Services and user preferences are described by a formal context model called Hyperspace Analogue to Context, which effectively captures the dynamics of context and the relationship between services and context. Based on the model, we propose a set of algorithms that can continuously present the most relevant services to the user in response to changes of context, services or user preferences. Numeric coding methods are applied to improve the algorithms’ performance. The algorithms are grounded in a context-driven service discovery system that automatically reacts to changes in the environment. New context sources and services can be dynamically integrated into the system. A client for smart phones continuously informs users about the discovery results. Experiments show, that the system can efficiently provide the user with continuous, up-to-date information about the most useful services in real time.     

Affective e-Learning in residential and pervasive computing environments

This article examines how emerging pervasive computing and affective computing technologies might enhance the adoption of ICT in e-Learning which takes place in the home and wider city environment. In support of this vision we describe two cutting edge ICT environments which combine to form a holistic connected future learning environment. The first is the iSpace, a specialized digital-home test-bed that represents the kind of high-tech, context aware home-based learning environment we envisage future learners using, the second a sophisticated pervasive e-Learning platform that typifies the educational delivery platform our research is targeting. After describing these environments we then present our research that explores how emotion evolves during the learning process and how to leverage emotion feedback to provide adaptive e-Learning system. The motivation driving this work is our desire to improve the performance of the educational experience by developing learning systems that recognize and respond appropriately to emotions exhibited by learners. Finally we report on the results about the emotion recognition from physiological signals which achieved a best-case accuracy rate of 86.5% for four types of learning emotion. To the best of our knowledge, this is the first report on emotion detection by data collected from close-to-real-world learning sessions. We also report some finding about emotion evolution during learning, which are still not enough to validate Kort’s learning spiral model.

Context-aware active task discovery for pervasive computing

Task computing is mainly involved with how to interact with equipment and services for users. In such new mode users can only concern with the task need to be completed, without having to consider how to complete it. In recent years, this new mode has been considered the preferred choice under the environment of pervasive computing. Active task discovery is the key to task computing, which depends on context and automatically relates the corresponding services to complete the given operation. In this paper, based on active task computing model we present a new context-aware active task discovery mode and raise a good algorithm for discovering and executing task.     

Reasoning about uncertain contexts in pervasive computing environments

Context-aware systems can't always identify the current context precisely, so they need support for handling uncertainty. A prototype pervasive computing infrastructure, Gaia, allows applications and services to reason about uncertainty using mechanisms such as probabilistic logic, fuzzy logic, and Bayesian networks.     

普适计算环境下上下文信息推理的研究

从各种低层上下文信息得到对人们更加有用的高层上下文信息即上下文推理是当前研究的热点.针对该问题,采用描述逻辑,研究基于本体模型的上下文推理方法.首先简要介绍基于本体的上下文模型,该模型增加了对上下文特性的建模,然后分别研究基于本体的推理、基于规则的推理及不一致性验证3种推理方式,借助Jena框架的推理接口实现,推理功能全面,通用性强,基本满足了普适计算系统中上下文推理的需求,最后给出了推理的可用性.     

Trust force-based service selection in pervasive computing environments

Trust is an important aspect of decision making for pervasive applications and it is important to choose and use services efficiently in pervasive computing environments. Trust force is presented to specify trust relationships among interactive entities in a pervasive computing environment by using experience and knowledge in a social network and the coulomb＇s law in real word. Based on trust force, a Trust Management and Service Selection model are presented, named TMSS. TMSS was tested and the experimental results show that our method for selecting service is not only more efficient than traditional and heuristic methods, but also can identify good services from bad ones.     

Decentralized checking of context inconsistency in pervasive computing environments

Contexts are often inconsistent in pervasive computing environments, owing to many heterogeneous devices with limited processing capabilities, imperfect measurement techniques, and user movement. A variety of schemes have been proposed to check context inconsistency. However, they implicitly require central control. This requirement inhibits their effectiveness in some pervasive computing environments (e.g., transport systems) where all nodes are resource-constrained and cannot act as a centralized node. To this end, we propose in this paper DCCI—a scheme of Decentralized Checking of Context Inconsistency in pervasive computing environments. DCCI exploits a simple, yet efficient, preference-based locality that denotes nodes requiring that the same context can check the inconsistency on this type of contexts. According to this locality, DCCI constructs a preference-based shortcut structure such that it checks context inconsistency within the shortcut structure. Extensive experiments show that DCCI can accurately and efficiently check context inconsistency in the presence of node churns and heterogeneity.     

EASY: Efficient semAntic Service discoverY in pervasive computing environments with QoS and context support

Pervasive computing environments are populated with networked software and hardware resources providing various functionalities that are abstracted, thanks to the Service Oriented Architecture paradigm, as services. Within these environments, service discovery enabled by service discovery protocols (SDPs) is a critical functionality for establishing ad hoc associations between service providers and service requesters. Furthermore, the dynamics, the openness and the user-centric vision aimed at by the pervasive computing paradigm call for solutions that enable rich, semantic, context- and QoS-aware service discovery. Although the semantic Web paradigm envisions to achieve such support, current solutions are hardly deployable in the pervasive environment due to the costly underlying semantic reasoning with ontologies. In this article, we present EASY to support efficient, semantic, context- and QoS-aware service discovery on top of existing SDPs. EASY provides EASY-L, a language for semantic specification of functional and non-functional service properties, as well as EASY-M, a corresponding set of conformance relations. Furthermore, EASY provides solutions to efficiently assess conformance between service capabilities. These solutions are based on an efficient encoding technique, as well as on an efficient organization of service repositories (caches), which enables both fast service advertising and discovery. Experimental results show that the deployment of EASY on top of an existing SDP, namely Ariadne, enhancing it only with slight changes to EASY-Ariadne, enables rich semantic, context- and QoS-aware service discovery, which furthermore performs better than the classical, rigid, syntactic matching, and improves the scalability of Ariadne.     

Context reasoning using extended evidence theory in pervasive computing environments

Most existing context reasoning approaches implicitly assume that contexts are precise and complete. This assumption cannot be held in pervasive computing environments, where contexts are often imprecise and incomplete due to unreliable connectivity, user mobility and resource constraints. To this end, we propose an approach called CRET: Context Reasoning using extended Evidence Theory. CRET applies the evidence theory to context reasoning in pervasive computing environments. Because evidence theory is limited by two fundamental problems–computation-intensiveness and Zadeh paradox, CRET presents evidence selection and conflict resolution strategies. Empirical study shows that CRET is desirable for pervasive applications.     

Direction-aware resource discovery in large-scale distributed computing environments

As a system scales up, the peer-to-peer (P2P) approach is attractive to distributed computing environments, such as Grids and Clouds, due to the amount of resources increased. The major issue in large-scale distributed systems is to prevent the phenomenon of a communication bottleneck or a single point of failure. Conventional approaches may not be able to apply directly to such environments due to restricted queries and varied resource characteristics. Alternatively, a fully decentralized resource discovery service based on an unstructured overlay, which relies only on the information of resource attributes and characteristics, may be a feasible solution. One major challenge of such service is to locate desired and suitable resources without the global knowledge of distributed sharing resources. As a consequence, the more nodes the resource discovery service involves, the higher the network overhead incurs. In this paper, we proposed a direction-aware strategy which can alleviate the network traffic among unstructured information systems for distributed resource discovery service. Experimental results have demonstrated that the proposed approach achieves higher success rate at low cost and higher scalability.     

Shadow attacks on users’ anonymity in pervasive computing environments

Privacy preserving technologies are likely to become an essential component of adaptive services in pervasive and mobile computing. Although privacy issues have been studied for a long time in computer science as well as in other fields, most studies are focused on the release of data from large repositories. Mobile and pervasive computing pose new challenges, requiring specific formal models for attacks and new privacy preserving techniques. This paper considers a specific pervasive computing scenario, and shows that the application of state-of-the-art techniques for the anonymization of service requests is insufficient to protect the privacy of users. A specific class of attacks, called shadow attacks, is formally defined and a defense technique is proposed. This defense is formally proved to be correct, and its effectiveness is validated by extensive experiments in a simulated environment.     

Model-driven engineering of planning and optimisation algorithms for pervasive computing environments

This paper presents a model-driven approach to developing pervasive computing applications that exploits design-time information to support the engineering of planning and optimisation algorithms that reflect the presence of uncertainty, dynamism and complexity in the application domain. In particular, the task of generating code to implement planning and optimisation algorithms in pervasive computing domains is addressed.We present a layered domain model that provides a set of object-oriented specifications for modelling physical and sensor/actuator infrastructure and state-space information. Our model-driven engineering approach is implemented in two transformation algorithms. The initial transformation parses the domain model and generates a planning model for the application being developed that encodes an application’s states, actions and rewards. The second transformation parses the planning model and selects and seeds a planning or optimisation algorithm for use in the application.We present an empirical evaluation of the impact of our approach on the development effort associated with two pervasive computing applications from the Intelligent Transportation Systems (ITS) domain, and provide a quantitative evaluation of the performance of the algorithms generated by the transformations.     

Prototypes in pervasive computing

In product design, prototypes - approximations of a product along some dimensions - are the essential medium for information, interaction, integration, and collaboration. Information appliances such as mobile phones, digital cameras, and music players are a growing area of ubiquitous computing. Designers currently create two separate sets of prototypes: "looks-like" prototypes that show only the device's form (the atoms) and "works-like" prototypes that use a computer display to demonstrate the interaction (the bits). Because of the required skill and time investment, designers don't build comprehensive prototypes that join form and function until late in development.     

Toward pervasive computing

Summary form only given. The fundamental principles that guide pervasive computing environment design evolved with distributed systems: local area networks, middleware, wide-area networks, the WWW. Over the years, ever smaller, portable computers came on the market and wireless networking technology evolved, leading to the emergence of mobile and wireless computing. Embedded computing gave us small devices, sensors and actuators, increasingly with communications capability. There are now substantial projects that demonstrate that sensor-rich environments, such as active buildings and cities, are feasible and will be deployed widely in the real world in the near future. This issue of Pervasive Computing describes several such projects.