Abstract

Abstract
Sequences of data-dependent tasks, each one traversing large data sets, exist in many applications (such as video, image and signal processing applications). Those tasks usually perform computations (with loop intensive behavior) and produce new data to be consumed by subsequent tasks. This paper shows a scheme to pipeline sequences of data-dependent loops, in such a way that subsequent loops can start execution before the completion of the previous ones, which achieves performance improvements. It uses a hardware scheme with decoupled and concurrent data-path and control units that start execution at the same time. The communication of array elements between two loops in sequence is performed by special buffers with a data-driven, fine-grained scheme. Buffer elements are responsible to flag the availability of each array element requested by a subsequent loop (i.e., a ready protocol is used to trigger the execution of operations in the succeeding loop). Thus, the control execution of following loops is also orchestrated by data availability (in this case at the array element grain) and out-of-order produced-consumed pairs are permitted. The concept has been applied using Nau, a compiler infrastructure to map algorithms described in Java onto FPGAs. This paper presents very encouraging results showing important performance improvements and buffer size reductions for a number of benchmarks.

Abstract
This paper presents an overview regarding the synthesis of regular expressions targeting FPGAs. It describes current solutions and a number of open issues. Implementation of regular expressions can be very challenging when performance is critical. Software implementations may not be able to satisfy performance requirements and thus dedicated hardware engines have to be used. In the later case, automatic synthesis tools are of paramount importance to achieve fast prototyping of regular expression engines. As a case study, experimental results are presented, for FPGA implementations of the regular expressions included in the rule-set of a Network Intrusion Detection System (NIDS), Bleeding Edge, obtained using a state-of-the-art synthesis approach.

Abstract

Abstract
The growth of the Internet and its associated technologies did open space for a new type of human interaction: virtual, social interaction environments. The introduction of regulated interaction in these virtual interaction spaces may be a solution towards their organization and inherent increased credibility. In this paper we propose a model for interaction regulation and control for virtual, social interaction spaces, called Social Theatres. A multi-layer software architecture was developed to support this web-based interaction model, allowing easy construction of such social interaction spaces and adaptation to users' devices. This paper discusses the advantages of regulated interaction, addresses the Social Theatre metaphor and presents the software architecture for the implementation of these regulated social interaction spaces.

Abstract
The growth of the Internet and its associated technologies did open space for a new type of human interaction: virtual, social interaction environments. Nowadays, these virtual places are spread all over the Internet and are accessible to almost everyone. However, in these environments interaction is still mostly ad hoc, which is a drawback that, as pointed out by some authors, may lead to their future extinction. Therefore, the introduction of regulated interaction in these virtual interaction spaces may be a solution towards their organization and inherent increased credibility. In this paper we propose a model for interaction regulation and control for virtual, social interaction spaces, called Social Theatres. Social Theatres stand for the application of the theatrical metaphor to social virtual environments, intended to virtually reproduce some of the common useful people interaction contexts. Inside these environments, users become actors, playing previously well defined roles within a well known, commonly established virtual interaction scenario. The interaction between users becomes regulated and has to obey and follow very well established rules, flows and conversation protocols. This paper discusses the advantages of regulated interaction, presents the Social Theatre metaphor and proposes a software architecture for the implementation of these interaction spaces. A small case study of a regulated virtual interaction environment is also presented.