Application coordination in pervasive systems

Our future environment will be managed by a multitude of different pervasive systems. A pervasive system consists of users and devices which cooperate to provide functionality to the users. The provision of functionality is realized by pervasive applications. A major characteristic of pervasive applications is their context-interactivity. On one hand, pervasive applications are context-aware and can adapt themselves to changing context. This ability enables them to provide their functionality in different configurations. On the other hand, pervasive applications have the ability to influence and change the context themselves. A context change can be caused implicitly as a side effect of employed resources or explicitly through the use of actuators. Due to the context-interactivity, problems are likely to occur when two or more applications are executed in the same physical space. Since applications share a common context and interact with it, they can have a direct impact on each other. The described problem is defined as an interference in this thesis. An interference is an application-produced context that impairs the functionality provision of another application. To manage interferences in pervasive systems, a coordination framework is presented. The framework detects interferences using a context model and information about how applications interact with the shared context. The resolution of an interference is achieved through a coordinated application adaptation. The idea is based on the assumption that an alternative application configuration may yield a different context interaction. Thus, the framework determines a configuration for each application such that the context interactions do not interfere. Once a configuration is found for each application, the framework instructs applications to instantiate the selected configuration, resolving the interference. The framework is unique due to three design decisions. At first, the framework is realized as a cross-system coordination layer in order to allow an integration of arbitrary systems. Secondly, the integration of applications can be achieved through the extension of existing systems while preserving their system characteristics. Thirdly, the framework supports a generic interface to integrate arbitrary resolution strategies in order to allow the customization of the framework to the needs of different pervasive systems. The thesis introduces the theoretical concepts of the framework, presents a prototypical implementation and evaluates the prototype and its implemented concepts through extensive measurements

Architecturing Conflict Handling of Pervasive Computing Resources

International audiencePervasive computing environments are created to support human activities in different domains (e.g., home automation and healthcare). To do so, applications orchestrate deployed services and devices. In a realistic setting, applications are bound to conflict in their usage of shared resources, e.g., controlling doors for security and fire evacuation purposes. These conflicts can have critical effects on the physical world, putting people and assets at risk. This paper presents a domain-specific approach to architecturing conflict handling of pervasive computing resources. This approach covers the software development lifecycle and consists of enriching the description of a pervasive computing system with declarations for resource handling. These declarations are used to automate conflict detection, manage the states of a pervasive computing system, and orchestrate resource accesses accordingly at runtime. In effect, our approach separates the application logic from resource conflict handling. Our approach has been implemented and validated on various building automation applications

Quality of Context in Context-Aware Systems

Context-aware Systems (CASs) are becoming increasingly popular and can be found in the areas of wearable computing, mobile computing, robotics, adaptive and intelligent user interfaces. Sensors are the corner stone of context capturing however, sensed context data are commonly prone to imperfection due to the technical limitations of sensors, their availability, dysfunction, and highly dynamic nature of environment. Consequently, sensed context data might be imprecise, erroneous, conflicting, or simply missing. To limit the impact of context imperfection on the behavior of a context-aware system, a notion of Quality of Context (QoC) is used to measure quality of any information that is used as context information. Adaptation is performed only if the context data used in the decision-making has an appropriate quality level. This paper reports an analytical review for state of the art quality of context in context-aware systems and points to future research directions

The Political Nature of Defense Policy in Congress

Is defense policy more collegial than other policy issues addressed by Congress? More specifically, what are the institutional and political motives which drive a majority of the members of Congress to consistently transcend partisanship in order to pass defense focused legislation into law? The purpose of this study was to test whether or not the consideration of defense policy in the House of Representatives is unique in its ability to transcend partisanship. And if so, why? Hypothesis: The formulation of defense policy in the U.S. House of Representatives is approached with more collegiality than other policy issue areas, mainly due to institutional, domestic, and international political pressures on members that transcend competing partisan motivations. Defense policy was operationalized by the National Defense Authorization Act (NDAA). “Other types of policy” was operationalized by the Farm Bill and the Highway Bill. “Collegiality,” the primary dependent variable, was defined as exceptional and consistent cooperative interaction among colleagues over time that rendered legislation which garnered support of at least a bipartisan supermajority (two-thirds) of the House of Representatives upon its final passage. A mixed methods approach was employed using the annual NDAA process as a study vehicle. Qualitative and quantitative analysis included case studies of U.S. legislative history that compared the NDAA process with that of the Farm Bill and Highway Bill. Deliberations over the bills were explored during three five-year periods of notable partisanship in U.S. politics that coupled with notable U.S. security concerns abroad: 1961-66, 1993-98, and 2007-12. Case studies were complemented by interviews with 25 members of the policy community The study concluded that the NDAA is essentially a de facto annual omnibus authorization bill with unparalleled political and institutional momentum that serves individual policymaker interests as well as the public interest. As such, the NDAA is an institution unto itself and its annual process consistently demands House members approach it in a uniquely collegial manner, providing strong evidence defense policy formulation is more collegial than other policy areas

'You see, it's sort of tricky for the L2-user': the puzzle of idiomaticity in English as a lingua franca

Much has been claimed recently for the role of idiomaticity in L1 acquisition and fluency and many of these insights have been applied, in my view, uncritically in many cases, to the context of L2 use. Until recently, very little attempt was made to test out the applicability of these insights to English as a Lingua Franca by examining naturally-occurring L2 discourse. This thesis sets out to explore the reasons why even successful L2-users may find the phenomenon of idiomaticity difficult. It investigates the apparent paradox between idiomaticity in L1 use and L2 use, whereby for the L1-user, idiomaticity, in all its guises, makes for ease of processing and the promotion of fluency while in L2 use it seems, in some of its manifestations at least, to be error- prone and elusive. Drawing on an original corpus of spoken English as a Lingua Franca, I apply a combination of corpus techniques and techniques of discourse analysis within a sociocultural framework in order to identify the underlying factors that differentiate L1 and L2 idiomaticity. I illustrate the argument by looking at two different manifestations of idiomaticity: ‘minimal’ units of idiomaticity (two word phrases) and more traditional ‘colourful’ idioms. The results suggest that L2-users avoid or have difficulty with ‘native-like’ idiomaticity because L1 idiomaticity involves more than formulaic sequences of greater or lesser semantic opacity; it is a more extended and diffuse phenomenon that generates subtle webs of semantic, pragmatic and discourse prosodies. It is through these situated webs of signification that L1-users achieve fluency and the promotion of self rather than in the manipulation of isolated idiomatic units in vacuo. Note: When I use the terms ‘native’ and ‘non-native’ I put them in inverted commas to indicate to the reader that I do not subscribe to the deficit view of L2 use that these terms are often associated with. My preferred terms are ‘L1-user’ and ‘L2-user’ (Cook, 2002)

Toward a Criminal Law for Cyberspace: Distributed Security

Cybercrime creates unique challenges for the reactive model of crime control that has been predominant for approximately the last century and a half. That model makes certain assumptions about crime, which derive from characteristics of real-world crime. These assumptions do not hold for cybercrime, so the reactive model is not an appropriate means of dealing with online crime. The article explains how modified principles of criminal law can be utilized to implement a new, non-reactive model which can deal effectively with cybercrime. This model of distributed security emphasizes prevention, rather than reaction, which is achieved by holding citizens liable for their failure to prevent cybercrime