Request-Based Mediated Execution

How do you dynamically customize the programming language available in a context within an existing system, without changing the underlying system? This dissertation introduces a language design approach that addresses this problem. The basic idea is to structure programs as systems of multiple interacting levels of abstraction, where all of the primitive constructs used by higher levels are actually implemented as defined constructs by lower levels. This is accomplished by allowing lower levels to mediate the execution of higher levels. This structure is much like system-level virtualization, but much finer-grained. The approach builds on three existing programming language technologies: delimited continuations, dynamic scoping, and call-by-name nonstrict evaluation. The dissertation examines how to define a variety of different language constructs using this approach, including variable binding, control structures, and basic concurrency features. The approach is then applied to mediating execution of third-party Javascript code on web pages.unpublishedis peer reviewe

ActorNet: An Actor Platform for Wireless Sensor Networks

We present an actor platform for wireless sensor networks (WSNs). A typical WSN may consist of hundreds to tens of thousands of tiny nodes embdedded in an environment. Hence, manual reprogramming of nodes for development, fixing bugs and updating features is an arduous process; moreover, in some cases physical access to nodes is simply out of the question. In an attempt to address this problem, network reprogramming tools such as Deluge and MNP have been developed. Unfortunately, these bulk reprogramming services incur significant costs in terms of energy usage, latency, and loss of sensing coverage when nodes are rebooted into a new program image. ActorNet, in contrast, provides an environment for lightweight concurrent object-oriented mobile code on WSNs. As such, actorNet enables a wide range of new dynamic applications on WSNs, including support for fully customizable queries and aggregation functions, in-network interactive debugging facilities, and high-level concurrent programming on the inherently parallel sensor network platform. Moreover, actorNet cleanly integrates all of these features into a fine-tuned, multi-threaded embedded Scheme interpreter which supports compact, maintainable programs -- a significant advantage over primitive stack-based virtual machines

Request-Based Mediated Execution

126 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.How do you dynamically customize the programming language available in a context within an existing system, without changing the underlying system? This dissertation introduces a language design approach that addresses this problem. The basic idea is to structure programs as systems of multiple interacting levels of abstraction, where all of the primitive constructs used by higher levels are actually implemented as defined constructs by lower levels. This is accomplished by allowing lower levels to mediate the execution of higher levels. This structure is much like system-level virtualization, but much finer-grained. The approach builds on three existing programming language technologies: delimited continuations, dynamic scoping, and call-by-name nonstrict evaluation. The dissertation examines how to define a variety of different language constructs using this approach, including variable binding, control structures, and basic concurrency features. The approach is then applied to mediating execution of third-party Javascript code on web pages.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Localization of Sparse Sensor Networks Using Layout Information

Localization is the process by which sensor networks associate spatial position information with individual sensors' measurements. While manual surveying is sufficient for small-scale prototypes, it is too time-consuming and costly for the large-scale deployments anticipated in the near future. Our experiments with medium-scale outdoor sensor network deployments show that sparsity of ranging measurements is a key factor limiting the accuracy of localization; often, several solutions are equally consistent with the data. Fortunately, layout information can usually be obtained at little extra cost; for example, if it is used to guide the deployment process, or by analyzing a photograph of the network. We have developed an algorithm based on subgraph isomorphism which uses the known layout information in conjunction with ranging measurements to find a family of localization solutions for a sensor network deployment. Although subgraph isomorphism is in general NP-complete, the more specific cases that occur in real-world scenarios are usually tractable. Experiments with a 50-node network show that our algorithm is very efficient in practice

Resilient Localization for Sensor Networks in Outdoor Environments

A process which computes the physical locations of nodes in a wireless sensor network is called localization. Self-localization is critical for large-scale sensor networks because manual or assisted localization is often impractical due to time requirements, economic constraints or inherent limitations of deployment scenarios. We have developed a service for reliably localizing wireless sensor networks in environments conducive to ranging errors by using a custom hardware-software solution for acoustic ranging and a family of self-localization algorithms. The ranging solution improves on previous work, extending the practical measurement range threefold (20-30m) while maintaining a distance-invariant median measurement error of about 1% of maximum range (33cm). The localization scheme is based on least squares scaling with soft constraints. Evaluation using ranging results obtained from sensor network field experiments shows that the localization scheme is resilient against large-magnitude ranging errors and sparse range measurements, both of which are common in large-scale outdoor sensor network deployments

ActorNet: An actor platform for wireless sensor networks

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SENS: A Sensor, Environment and Network Simulator

Recent advances in micro electro-mechanical systems and VLSI lithography have enabled the miniaturization of sensors and controllers. Such minitiarization facilitates the deployment of large-scale wireless sensor networks (WSNs). However, the considerable cost of deploying and maintaining large-scale WSNs for experimental purposes makes simulation useful in developing dependable and portable WSN applications. SENS is a customizable sensor network simulator for WSN applications, consisting of interchangeable and extensible components for applications, network communication, and the physical environment. Multiple component implementations in SENS offer varying degrees of realism. Users can assemble application-specific environment