A Query-Centric Approach to Supporting the Development of Context-Aware Applications for Mobile Ad Hoc Networks, Doctoral Dissertation, August 2006

The wide-spread use of mobile computing devices has led to an increased demand for applications that operate dependably in opportunistically formed networks. A promising approach to supporting software development for such dynamic settings is to rely on the context-aware computing paradigm, in which an application views the state of the surrounding ad hoc network as a valuable source of contextual information that can be used to adapt its behavior. Collecting context information distributed across a constantly changing network remains a significant technical challenge. This dissertation presents a query-centered approach to simplifying context interactions in mobile ad hoc networks. Using such an approach, an application programmer views the surrounding world asa single data repository over which descriptive queries can be issued. Distributed context information appears to be locally available, effectively hiding the complex networking tasks required to acquire context in an open and dynamic setting. This dissertation identifies the research issues associated with developing a query-centric approach and discusses solutions to providing query-centric support to application developers. To promote rapid and dependable software development, a query-centric middleware is provided to the application programmer. These solutions provide the means to reason about the correctness of an application\u27s design and potentially to reduce programmer effort and error

Incentive Mechanisms for Participatory Sensing: Survey and Research Challenges

Participatory sensing is a powerful paradigm which takes advantage of smartphones to collect and analyze data beyond the scale of what was previously possible. Given that participatory sensing systems rely completely on the users' willingness to submit up-to-date and accurate information, it is paramount to effectively incentivize users' active and reliable participation. In this paper, we survey existing literature on incentive mechanisms for participatory sensing systems. In particular, we present a taxonomy of existing incentive mechanisms for participatory sensing systems, which are subsequently discussed in depth by comparing and contrasting different approaches. Finally, we discuss an agenda of open research challenges in incentivizing users in participatory sensing.Comment: Updated version, 4/25/201

A Principled Exploration of Coordination Models

Coordination is a style of interaction in which information exchange among independent system components is accomplished by means of high-level constructs designed to enhance the degree of decoupling among participants. A de-coupled mode of computation is particularly important in the design of mobile systems which emerge dynamically through the composition of independently developed components meeting under unpredictable circumstances and thrust into achieving purposeful cooperative behaviors. This paper examines a range of coordination models tailored for use in mobile computing and shows that the constructs they provide are reducible to simple schema definitions in Mobile UNITY. Intellectually, this exercise contributes to achieving a better operational-level understanding of the relation among several important classes of models of mobility. Pragmatically, this work demonstrates the immediate applicability of Mobile UNITY to the formal specification of coordination constructs supporting mobile computing. Moreover, the resulting schemas are shown to be helpful in reducing the complexity of the formal verification effort

A Termination Detection Protocol for Use in Mobile Ad Hoc Networks

As computing devices become smaller and wireless networking technologies improve, the popularity of mobile computing continues to rise. In today\u27s business world, many consider devices such as cell phones, PDAs, and laptops as essential tools. As these and other devices become increasingly independent of the wired infrastructure, new kinds of applications that assume an ad hoc network infrastructure will need to be deployed. Such a setting poses new challenges for the software developer, e.g., the lack of an established network topology, bandwidth limitations, and frequent disconnections. In this paper, we begin to explore design strategies for developing applications over ad hoc networks. The study of termination detection in diffusing computations, along with the formulation of an algorithmic solution amenable to usage in mobile ad joc networks, gives us the opportunity to bring to light several important software engineering concerns and design strategies one might employ in a mobile setting. We view this effort as a first step towards creating a repertoire of commonly used design solutions for frequently encountered problems in the development of applications over mobile ad hoc networks

An Architecture to Support Learning-based Adaptation of Persistent Queries in Mobile Environments

Queries are frequently used by applications in dynamically formed mobile networks to discover and acquire information and services available in the surrounding environment. A number of inquiry strategies exist, each of which embodies an approach to disseminating a query and collecting results. The choice of inquiry strategy has different tradeoffs under different operating conditions. Therefore, it is beneficial to allow a query-based application to dynamically adapt its inquiry strategy to the changing environmental conditions. To promote development by non-expert domain programmers, we can automate the decision-making process associated with adapting the inquiry strategy. In this paper, we propose an architecture to support automated adaptative query processing for dynamic mobile environments. The decision-support module of our architecture relies on an instance-based learning approach to support context-aware adaptation of the inquiry strategy

Simplifying Context-Aware Agent Coordination Using Context-Sensitive Data Structures

Context-aware computing, an emerging paradigm in which applications sense and adapt their behavior to changes in their operational environment, is key to developing dependable agent-based soft-ware systems for use in the often unpredictable settings of ad hoc net-works. However, designing an application agent which interacts with other agents to gather, maintain, and adapt to context can be a difficult undertaking in an open and continuously changing environment, even for a seasoned programmer. Our goal is to simplify the programming task by hiding the details of agent coordination from the programmer, allowing one to quickly and reliably produce a context-aware application agent for use in large-scale ad hoc networks. With this goal in mind, we introduce a novel abstraction called context-sensitive data structures (CSDS). The programmer interacts with the CSDS through a familiar programming interface, without direct knowledge of the context gathering and maintenance tasks that occur behind the scenes. In this paper, we define a model of context-sensitive data structures, and we identify key requirements and issues associated with building an infrastructure to support the development of context-sensitive data structures

Bringing Context-Awareness to Applications in Ad Hoc Mobile Networks

Context-aware mobile applications require constant adapta-tion to their changing environments. Technological advancements have increased the pervasiveness of mobile computing devices such as laptops, handhelds, cellular phones, and embedded sensors. The sheer amount of context information necessary for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this data-rich environment requires a middleware infrastructure for sensing, collect-ing, and providing context information to applications. In this paper, we demonstrate the feasibility of providing such a middleware that allows programmers to focus on high-level interactions among programs and to employ declarative abstract specifications of context in settings that exhibit high levels of mobility and transient interactions with opportunis-tically encountered components. We also discuss the novel context-aware abstractions the middleware provides and the programming knowledge necessary to write applications using our middleware. Finally, we provide examples demonstrating the flexibility of the infrastructure and its abil-ity to support differing tasks from a wide variety of application domains

A Software Engineering Perspective on Context-Awareness in Ad Hoc Mobile Environments

Context-aware mobile applications require constant adaptation to their changing environments. Technological advancements have increased the pervasiveness of mobile computing devices such as laptops, handhelds, cellular phones, and embedded sensors. The sheer amount of context information necessary for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this data-rich environment requires an infrastructure for sensing, collecting, and providing context information to applications. In this paper, we demonstrate the feasibility of providing such an infrastructure. It allows programmers to focus on high-level interactions among programs and to employ declarative abstract specifications of context in settings that exhibit high levels of mobility and transient interactions with opportunistically encountered components. We also discuss the novel context-aware abstractions we implemented and the programming knowledge necessary to write applications using our middleware. Finally, we provide examples that demonstrate the flexibility of the infrastructure and its ability to support a variety of applications

Reasoning About Context-Awareness in the Presence of Mobility

Context-awareness is emerging as an important computing paradigm designed to address the special needs of applications that must accommodate or exploit the highly dynamic environments that occur in the presence of physical or logical mobility. A number of formal models are available for reasoning about concurrency. Models designed to capture the specifics of mobility are fewer but still well represented (e.g., Mobile Ambients, π-Calculus, and Mobile UNITY). These models do not, however, provide constructs necessary for explicit modeling of context-aware interactions. This paper builds upon earlier efforts on state-based formal reasoning about mobility and explores the process by which a model such as Mobile UNITY can be transformed to explicitly capture context-awareness. Starting with an ex-amination of the essential features of context-aware systems, this paper explores a range of constructs designed to facilitate a highly decoupled style of programming among context-aware components. The result of this exploration is a model called Context UNITY

Context-Sensitive Data Structures Supporting Software Development in Ad Hoc Mobile Settings

Context-aware computing, an emerging paradigm in which applications sense and adapt their behavior to changes in their operational environment, is key to developing dependable software for use in the often unpredictable settings of ad hoc networks. However, designing an application which gathers, maintains, and adapts to context can be a difficult undertaking, even for a seasoned programmer. Our goal is to simplify the programming task by hiding such issues from the programmer, allowing one to quickly and reliably produce a context-aware application for use in ad hoc networks. With this goal in mind, we introduce a novel abstraction called context-sensitive data structures (CSDS). The programmer interacts with the CSDS through a familiar programming interface, without direct knowledge of the context gathering and maintenance tasks that occur behind the scenes. In this paper, we define a model of context-sensitive data structures and present protocols which enable the programmer to construct and main-tain a CSDS as a distributed structure over a mobile ad hoc network in a state of flux