Toward a standard ubiquitous computing framework

This paper surveys a variety of subsystems designed to be the building blocks from which sophisticated infrastructures for ubiquitous computing are assembled. Our experience shows that many of these building blocks fit neatly into one of five categories, each containing functionally-equivalent components. Effectively identifying the best-fit “lego pieces”, which in turn determines the composite functionality of the resulting infrastructure, is critical. The selection process, however, is impeded by the lack of convention for labeling these classes of building blocks. The lack of clarity with respect to what ready-made subsystems are available within each class often results in naive re-implementation of ready-made components, monolithic and clumsy implementations, and implementations that impose non-standard interfaces onto the applications above. This paper explores each class of subsystems in light of the experience gained over two years of active development of both ubiquitous computing applications and software infrastructures for their deployment

Mediabroker: An architecture for pervasive computing

MediaBroker is a distributed framework designed to support pervasive computing applications. Specifically, the architecture consists of a transport engine and peripheral clients and addresses issues in scalability, data sharing, data transformation and platform heterogeneity. Key features of MediaBroker are a type-aware data transport that is capable of dynamically transforming data en route from source to sinks; an extensible system for describing types of streaming data; and the interaction between the transformation engine and the type system. Details of the MediaBroker architecture and implementation are presented in this paper. Through experimental study, we show reasonable performance for selected streaming media-intensive applications. For example, relative to baseline TCP performance, MediaBroker incurs under 11 % latency overhead and achieves roughly 80 % of the TCP throughput when streaming items larger than 100 KB across our infrastructure

UbiqStack -- A taxonomy for a . . .

This paper describes a taxonomy for ubiquitous computing software stack called UbiqStack. Through the lens of the UbiqStack taxonomy we survey a variety of subsystems designed to be the building blocks from which sophisticated infrastructures for ubiquitous computing are assembled. Our experience shows that many of these building blocks fit neatly into one of five UbiqStack categories, each containing functionally-equivalent components. Effectively identifying the best-fit “Lego pieces”, which in turn determines the composite functionality of the resulting infrastructure, is critical. The selection process, however, is impeded by the lack of convention for labeling these classes of building blocks. The lack of clarity with respect to what ready-made subsystems are available within each class often results in naive reimplementation of ready-made components, monolithic and clumsy implementations, and implementations that impose non-standard interfaces onto the applications above. This paper describes the UbiqStack classes of subsystems and explores each in light of the experience gained over two years of active development of both ubiquitous computing applications and software infrastructures for their deployment

A single-stranded promoter for RNA polymerase III

Single strands of DNA serve, in rare instances, as promoters for transcription; duplex DNA promoters with individual strands that also have a promoter capacity/function have not been described. We show that the nontranscribed strand of the Saccharomyces cerevisiae U6 snRNA gene directs transcription initiation factor IIIB-requiring and accurately initiating transcription by RNA polymerase III. The nontranscribed strand promoter is much more extended than its duplex DNA counterpart, comprising the U6 gene TATA box, a downstream T(7) tract, and an upstream-lying segment. A requirement for placement of the 3′ end of the transcribed (template) strand within the confines of the transcription bubble is seen as indicating that the nontranscribed strand provides a scaffold for RNA polymerase recruitment but is deficient at a subsequent step of transcription initiation factor IIIB's direct involvement in promoter opening