Research Projects
The Mobile and Pervasive Computing Group's research revolves around software engineering issues related to mobile and pervasive computing. We are a member of UT's Center for Excellence in Distributed Global Environments (EDGE). Some information about our specific ongoing and completed research projects can be found on this page. Also see our Publications for up-to-date pending and published papers.

Table of Contents

Current Projects Past Projects

Current Projects

  • Gander: Search mechanisms for pervasive computing environments
    Gander is a distributed search engine for mobile networked environments characterized by high volumes of short-lived data. We refer to these emerging types of environments as Personalized Networked Spaces (PNetS).

    PNetS are comprised of digital devices, both mobile and embedded in the environment (e.g., smart phones, sensors, RFID tags), connected by a dynamic network topology. As in the Internet, large volumes of data motivate the need for expressive search mechanisms that efficiently identify and provide access to information relevant to users' needs. However, the volatile and heterogeneous nature of PNetS' network and data preclude traditional information retrieval techniques.

    This project aims to address the novel research and software engineering challenges that arise from the new requirements in this emerging search space.

    People
    • Jonas Michel, Dr. Christine Julien, Dr. Jamie Payton, Dr. Gruia-Catalin Roman

    Project Page:


  • Grapevine: Efficient situational awareness in pervasive computing environments
    Grapevine is a framework that enables applications to share context information in a localized region of a pervasive computing network, use that information to dynamically form groups defined by their shared situations, and assess the aggregate context of that group.

    Moving beyond more typical egocentric world views, Grapevine allows an application to distribute its own context information while simultaneously leveraging the context information it receives to modify its behavior and aggregate task-relevant group context information that can also distributed within the network. We use novel data structures such as probabilistic Bloomier filters to represent context information efficiently and minimize the network resources required to support Grapevine's use.

    Our long term vision is a framework that allows a pervasive computing application developer to delegate all context related functionality to Grapevine and focus solely on the task at hand. Instead of spending time determining what context information is needed, who it should be sent to, and managing the lifecycle of the information it has received, a Grapevine-enabled application can merely indicate the context information it has to offer and the context information it is interested in receiving. Achieving this vision leaves many interesting research challenges such as communicating and responding to interest gradients within the network, determining the frequency with which information should be sent, assessing a quality metric for the context information on hand, and finding ways to provide all this functionality without placing undue burden on the limited resources available to pervasive computing platforms.

    People
    • Evan Grim, Dr. Chien-Liang Fok, and Dr. Christine Julien

  • Delay Tolerant Networking
    The delay tolerant networking project is a multi-disciplinary research effort that spans software engineering, network protocols, all the way to the physical layer. It is a joint effort of three professors in the Department of Electrical and Computer Engineering at the Univeristy of Texas: Dr. Christine Julien, Dr. Sanjay Shakkottai, and Dr. Sriram Vishwanath.

    We are researching delay-tolerant middleware which will enable nodes to opportunistically and automatically adapt to changes in network and user context to make more intelligent use of the limited resources available in a delay-tolerant network. Our work is in the sensing and aggregation of context, as well as in the adaptation mechanisms as they apply to delay-tolerant routing and transport protocols. This project is sponsored by the Department of Defense.

    People
    • Tony Petz, Justin Enderle, and Dr. Christine Julien

    MaDMAN Middleware Page:
    Old Project Page (no longer supported):


  • Programming Abstractions for Ubiquitous Computing
    This project is developing programming abstractions and development tools that enable application developers to effeciently interact with ubiquitous and pervasive systems. Traditional pervasive systems are typically designed for a specific application and can afford tight coupling between applications and the deployment technologies of the application's evironment. These application-specific deployments will soon give way to more generic and flexible deployments which will support multiple applications developed by disjoint development teams. To support this transistion we must provide consistent programming interfaces and flexible support to application developers.

    At the heart of this project is the need to find the proper level of abstraction for ubiquitous environments, and developing programming metaphors that are appropriate. Currently, we are pursuing two lines of research in this area. The Application Sessions Middleware project unifies the tasks of resource discovery and connection maintenance into a single session. The Evolving Tuples project provides a generic platform which is deployed to nodes in a pervasive environment. The Evolving Tuples platform can be leveraged by new applications without requiring updates to the individual nodes, while still protecting them from attackers.

    People
    • Dr. Drew Stovall and Dr. Christine Julien

    Project Pages:

  • Pervasive Computing Test Bed (Pharos Project)
    The PCTB is an interdisciplinary facility conceived to support research goals in a variety of fields related to mobile, ad-hoc, pervasive, and cyber-physical systems. By providing a central repository for hardware, software, and knowledge, the PCTB reduces the barriers to practical, hand-on testing and evaluation of new concepts, protocols, techniques, and methods.

    The PCTB is co-sponsored by the MPC Lab and the LINC Lab.

    People
    • Dr. Drew Stovall, Tony Petz, Justin Enderle, and Dr. Christine Julien

    Project Page

  • Simplifying the Programming of Intelligent Environments
    Intelligent environments, a research and sci-fi favorite, are lagging woefully behind predictions. Researchers alone cannot make smart spaces into a reality; we must open the development to everyone. This work aims to lower the barrier for entry of programming intelligent environments in two distinct ways: first, by providing an easy-to-understand middleware that allows average programmers to develop pervasive computing applications without a deep understanding of sensors and actuators and second, by providing an intuitive end-user programming framework that brings the power of intelligent environments to the masses.

    People
    • Seth Holloway and Dr. Christine Julien

    Project Pages:

  • Query Semantics for Dynamic Networks
    Self organized networks like mobile ad hoc networks and sensor networks enable pervasive computing applications to observe and monitor the physical world. Queries present an application-friendly abstraction to gather information from these emerging opportunistic networks. However, these networks are inherently dynamic because of changes induced by mobility and the unpredictable lifetime inherent to battery operated devices. Consequently, the state of the environment changes during the execution of a query. We propose to explore techniques to interpret the quality of information obtained from networks in the face of such dynamics. This project investigates the quality dimensions for both applications that require both immediate information just once and those that require periodic monitoring. Our ultimate goal is to present a software framework that allows software engineers the ability to exercise control over the data collection process and subsequently interpret how well the response represents the actual state of the environment. Interpreting the degree of dynamics allows application developers to write adaptive query processing applications easily where the application changes its behavior in response to changes in the environment constantly.

    People
    • Vasanth Rajamani and Dr. Christine Julien

    Collaborators
    • Dr Jamie Payton and Dr. Gruia-Catalin Roman

    Project Page:

  • Chameleon: Rapid Deployment of Adaptive Communication-Aware Applications
    This project addresses a framework that facilitates real-time routing protocol decisions based on given application and environmental characteristics. Our approach develops analytical models for important network layer performance measures capturing various inter-dependent factors that affect routing protocol behavior. In this project, we provide an analytical framework that expresses protocol performance metrics in terms of environment-, protocol-, and application-dependent parameters.

    My proposed framework will result in detailed models for two important metrics: end-to-end delay and throughput. We specify detailed models for the parameters embedded in the models with respect to the ability of network deployers, protocol designers, and application developers to reasonably provide the information. In a systematic manner, the project proposes the Chameleon software framework to integrate the analytical models with parameters specified by these three groups of stakeholders.

    People
    • Taesoo Jun and Dr. Christine Julien

    Project Page:

  • Cross-Layer Discovery and Routing
    In pervasive computing environments, applications find themselves in constantly changing operating conditions. Such applications often need to discover locally available resources on-demand. Communication protocols that base discovery not on the unique address of the destination but on application-level characteristics of the destination host can more closely match application requirements. Our Cross-Layer Discovery and Routing (CDR) protocol is one such example; using a simple extension to standard source routing used in mobile ad hoc networks, we have demostrated the ability to efficiently discover and maintain routes to resources using application information to define the target of discovery. In addition, because the types of resources desired may be common across pervasive computing applications, the discovery and routing tasks may benefit from some degree of proactivity. Following this motivation, we have extended our CDR protocol to an adaptive version that incorporates resource advertisement. We have built mechanisms to allow CDR to dynamically tune its behavior to optimize itself for a dynamic operating environment.

    People
    • Dr. Christine Julien

    Collaborators
    • Dr. Angela Dalton (Johns Hopkins Applied Research Labs)

    Project Page:

  • Resource and Task Allocation in Pervasive Computing Networks
    Given the scale and complexity of network-centric computing, enabling a sensor network to support multiple applications simultaneously is of paramount importance. In this project, we are investigating a formal framework for specifying the allocation of resources to the potentially competing tasks comprising these applications. We take the commonly used tiered sensor network architecture a step further, defining a range of tiers that, moving up and away from individual nodes, can provide increasingly abstract and application-specific behaviors. Within this sensor network, we categorize the tasks the network performs into three groups: capture tasks, storage tasks, and distribution tasks. Our goal is to allocate resources in the network, e.g, computation, storage and communication capabilities, to these tasks. In conjunction with our hierarchical model, we are defining a distributed algorithmic framework for dynamically determining how the task and resources in the sensor network can be best allocated to multiple concurrent and potentially competing applications.

    People
    • Dr. Nirmalya Roy, Vasanth Rajamani, and Dr. Christine Julien

  • Quality-of-Inference (QoINF)-Aware Context Determination
    Energy-efficient determination of an individual's context (both physiological and activity) is an important technical challenge for pervasive computing environments. Given the expected availability of multiple sensors, context determination may be viewed as an estimation problem over multiple sensor data streams. In this project we are developing a formal and practically applicable model to capture the tradeoff between the accuracy of context estimation and the communication overheads of sensing. In particular, we propose the use of tolerance ranges to reduce an individual sensor's reporting frequency, while ensuring acceptable accuracy of the derived context. In our vision, applications specify their minimally acceptable value for a Quality-of Inference (QoINF) metric. We introduce an optimization technique allowing a Context Service to compute both the best set of sensors, and their associated tolerance values, that satisfy the QoINF target at minimum communication cost. This approach is validated using a SunSPOT sensors testbed.

    People
    • Dr. Nirmalya Roy and Dr. Christine Julien

    Collaborators
    • Dr. Archan Misra (Telcordia Research) and Dr. Sajal K. Das (National Science Foundation)

    Project Page:

  • Passive Sensing for Context-Aware Mobile Computing
    As computing devices and their users become increasingly mobile, the demand for information about the application's environment, or context, becomes significantly important to the efficient and robust operation of mobile and pervasive computing systems. Applications must be able to adapt themselves to changing conditions to satisfy users' demands and expectations and to ensure that the application's resource usage matches the environment's capabilities. Sensing context using traditional means incurs network communication, which competes with the applications using the network and expends valuable network resources, especially communication bandwidth and battery power. In this project, we are exploring passively sensing context metrics. This results in measurements that are basically approximations of actual context, but can be collected with zero cost in terms of network communication. This project develops a model of passive context sensing and a general framework for building and deploying passively sensed context metrics.

    People
    • Dr. Nirmalya Roy, Taesoo Jun, and Dr. Christine Julien

    Collaborators
    • Dr. Angela Dalton (Johns Hopkins Applied Research Labs)

    Project Page:

Past Projects

  • DAIS: Declarative Applications in Immersive Environments: In this project, we are developing communication, coordination, and programming abstractions that allow a mobile application on a PDA to interact directly with resource-constrained sensors in the local environment to retrieve information on-demand without using a single network access point. The project includes novel abstractions for sensor data aggregation and fusion performed within the network on the resource constrained devices.

    Papers:

    Software:

  • Sliverware for Collaborative Mobile Applications: Despite computers' widespread use for supporting personal applications, very few programming frameworks exist for creating synchronous collaborative applications. Enabling real-time collaboration demands lightweight, modular middleware that enables the fine-grained interactions requried by collaborative applications. We have introduced sliverware that provides extreme modularity and customizability while at the same time realizing our goal of simplifying cooperative application development.

    Papers:

  • SMASH: Secure Mobile Agent Middleware: As software components become able to move among hosts in the network, a question arises in how to secure interactions between the agents and among the agents and their host platforms. SMASH investigates the variety of these security requirements, provides a mobile agent architecture that embodies them, and still allows agents to move and coordinate anonymously to a limited extent.

    Papers:
    • Pridgen, A. and Julien, C., "SMASH: Modular Security for Mobile Agents," In Software Engineering for Large-Scale Multi-Agent Systems V, Lecture Notes in Computer Science, 2007.
    • Pridgen, A. and Julien, C., "A Secure Modular Mobile Agent System," in Proceedings of the 5th International Workshop on Software Engineering for Large-Scale Multi-Agent Systems (SELMAS'2006) co-located with ICSE'06, Shanghai (China), May 2006.

  • Network Abstractions: The network abstractions model provides a formal abstract characterization of an application's context that extends to encompass a neighborhood within the ad hoc network. The model includes a context specification mechanism that allows individual applications to tailor their operating contexts to their personalized needs. The associated communication protocol, source initiated context construction, or SICC, provides this context abstraction in ad hoc networks through continuous evaluation of the context. This relieves the application developer of the obligation of explicitly managing mobility and its implications on behavior.

    Papers:

    Software:

  • EgoSpaces: EgoSpaces is a coordination model and middleware for ad hoc mobile environments that focuses on the needs of application development in ad hoc environments by proposing an agent-centered notion of context, called a view, whose scope extends beyonr the local host to data and resources associated with hosts and agents within a subnet surrounding the agent of interest. An agent may operate over multiple views whose definitions may change over time. An agent uses declarative specifications to constrain the contents of each view by employing a rich set of constraints that take into consideration properties of the individual data items, the agents that own them, the hosts on which the agents reside, and the physical and logical topology of the ad hoc network. We have formalized the concept of view, explored the notion of programming against views, discussed possible implementation strategies for transparent context maintenance, and generated a protoype system.

    Papers:

    Software:

  • Context UNITY: Context-aware computing refers to a paradigm in which applications sense aspects of the environment and use this information to adjust their behavior in response to changing circumstances. We have created a formal model and notation (Context UNITY) for expressing quintessential aspects of context-aware computations; existential quantification, for instance, proves to be higly effective in capturing the notion of discovery in open systems. Furthermore, Context UNITY treats context in a manner that is relative to the specific needs of an individual applications and promotes an approach to context maintenance that is transparent to the application.

    Papers:
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