This paper advocates the use of RESTful data services in mobile commerce information spaces. REST is a restriction of web services to a simple protocol centered on a limited set of access operations against data resources. This paper analyzes how REST may be used as a general design principle for mobile commerce spaces. This analysis is threefold. First, it provides an abstract component model that contains a minimal embodiment of the REST functionality needed to support mobile commerce. Second, it describes and analyzes the operation of a mobile commerce space, resulting in a reference REST-based data decomposition that may be reused across a variety of domains. Third, it provides and analyzes a set of usage cases in the mobile commerce domain, which can form the basis of future REST-oriented programming models and tools. This analysis is based on a substantial mobile commerce framework we have implemented, called Celadon. This framework is currently being used to demonstrate several ambitious mobile commerce applications.

Searching and presenting rich data using mobile devices is hard given their inherent I/O limitations. One approach for alleviating these limitations is device symbiosis, whereby the interaction with one’s personal mobile device is augmented by additionally engaging with more capable infrastructure d

Pervasive computing environments augment physical spaces with a large number of devices and services that help users perform different kinds of tasks. Users in these environments interact with one or more Web services using various devices to achieve their goals. One of the problems in these environments is discovering and coordinating different Web services for achieving the user's goals. Users may not be aware of which services and devices are available in an unfamiliar environment and how to interact with them in order to achieve their goals. In order to simplify a user's interaction with the environment, we present a novel approach of modeling and managing a user's interaction with the environment based on workflows. We have built a prototype, using the popular business workflow language (BPEL) that models various processes in pervasive environments as workflows. We found that this approach improves the usability of these environments. It also increases flexibility in changing the model of interaction without having to touch individual services and applications. This approach is particularly useful in helping visitors in public spaces like malls, museums, supermarkets and hospitals.

This paper proposes a component-based programming approach to discovery. In this approach, individual discovery protocols, access models and authentication mechanisms are represented as software components called handlers. Handlers are registered with and coordinated by a software framework called a discovery agent. Configured with a battery of handlers, a discovery agent answers query and advertisement requests on behalf of mobile and other applications and applies authentication and access control policies. Based on its set of handlers, a diversity of request types and formats can be routed, translated, and fulfilled by a discovery agent. Discovery agents can easily be reconfigured, adapted, and extended as new underlying discovery protocols or client request types must be supported. A discovery agent can operate as a Web service, and can be deployed by an enterprise to service discovery requests on behalf of visiting clients. A discovery agent can also operate as a trusted co-module running on a device, and is useful for supporting mobile applications which move among environments and must accommodate a diversity of local discovery protocols.

Abstract We give two parallel algorithms for sequence comparison on the Connection Machine 2 (CM‐2). The specific comparison measure we compute is theedit distance: given a finite alphabet ∑ and two input sequencesXϵ ∑+andYϵ ∑+the edit distanced(X,Y)is the minimum cost of transformingXintoYvia a series of weighted insertions, deletions and substitutions of characters. The edit distance comparison measure is equivalent to or subsumes a broad range of well known sequence comparison measures. The CM‐2 is very fast at performing parallel prefix operations. Our contribution consists of casting the problem in terms of these operations. Our first algorithm computesd(X,Y)usingNprocessors andO(M S)time units, whereM= min(|X|,||Y|) + 1,N= max(|X|,|Y|) + 1 andSis the time required for a parallel prefix operation. The second algorithm computesd(X,Y)usingNMprocessors andO((logNlogM)(S+R)) time units, whereRis the time for a ‘router’ communication step—one in which each processor is able to read data, in parallel, from the memory of any other processor. Our algorithms can also be applied to several variants of the problem, such as subsequence comparisons, and one—many and many‐many comparisons on 'sequence databases'.

The string editing problem for input strings x and y consists of transforming x into y by performing a series of weighted edit operations on x of overall minimum cost. An edit operation on x can be the deletion of a symbol from x, the insertion of a symbol in x or the substitution of a symbol of x with another symbol. This problem has a well-known $O(|x||y|)$ time-sequential solution. Efficient PRAM parallel algorithms for the string editing problem are given. If $m = \min (|x|,|y|)$ and $n = \max (|x|,|y|)$, then the CREW bound is $O(\log m \log n)$ time with $O({{mn} / {\log m}})$ processors. The CROW bound is $O(\log n(\log \log m)^{2})$ time with $O(mn/ \log \log m)$ processors. In all algorithms, space is $O(mn)$.