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With sensor networks expected to be deployed for long periods of time, the ability to reprogram them remotely is necessary for providing new services, fixing bugs, and enhancing applications and system software. Given the envisioned scales of future sensor network deployments, their restricted accessibility, and the limited energy and computing resources of(More)
Modern software must evolve in response to changing conditions. In the most widely used programming environments, code is static and cannot change at runtime. This poses problems for applications, that have limited down-time. More support is needed for dynamic evolution. In this paper we present an approach for supporting dynamic evolution of Java programs.(More)
Sensor networks are being deployed at massive scales, containing a range of platforms. Programming paradigms for sensor networks should meet the attendant challenges of scale and heterogeneity. Researchers have considered virtual machines as a means to address these challenges. However, in order to satisfy the resource limitations of sensor nodes, they(More)
Resource constrained systems often are programmed using an event-based model. Many applications do not lend themselves well to an event-based approach, but preemptive multithreading pre-allocates resources that cannot be used even while not in use by the owning thread. In this paper, we propose a hybrid approach called Y-Threads. Y-Threads provide separate(More)
There is considerable interest in developing runtime in-frastructures for programs that can migrate from one host to another. Mobile programs are appealing because they support efficient utilization of network resources and extensibil-ity of information servers. This paper presents a scheduling scheme for allocating resources to a mix of real-time and non(More)
A security policy states the acceptable actions of an information system, as the actions bear on security. There is a pressing need for organizations to declare their security policies, even informal statements would be better than the current practice. But, formal policy statements are preferable to support (1) reasoning about policies, e.g., for(More)
A widely used technique for securing computer systems is to execute programs inside protection domains that enforce established security policies. These containers , often referred to as sandboxes, come in a variety of forms. Although current sandboxing techniques have individual strengths, they also have limitations that reduce the scope of their(More)