Programming language RIGAL as a compiler writing tool

A b s t r a c t . A new programming language for compiler writing is described briefly in this paper. The main data structures are atoms, lists and trees. The control structures are based on a advanced pattern matching. All phases of compilation,including parsing, optimization and code generation, can be programmed in this language in short and readable form

A Unified Approach for the Integration of Distributed Heterogeneous Software Components

Proceedings of the 2001 Monterey Workshop (Sponsored by DARPA, ONR, ARO and AFOSR), pp: 109-119, Monterey, CA, 2001Distributed systems are omnipresent these days. Creating efficient and robust software for such systems is a highly complex task. One possible approach to developing distributed software is based on the integration of heterogeneous sofwtare components that are scattered across many machines. In this paper, a comprehensive framework that will allow a seamless integration of distributed heterogeneous software components is proposed. This framework involves: a) a metamodel for components and associated hierarchical setup for indicating the contracts and constraints of the components. b) an automatic generation of glues and wrappers, based on a designer's specifications, for achieving interoperability, c) a formal mechanism for precisely describing the meta-model, and d) a formalization of quality of service (QoS) offered by each component and ensemble of components. A case study from the domain of distributed information filtering is described in the context of this framework.This material is based upon work supported by, or in part by, the U.S. Office of Naval Research under award number N00014-01-1-0746. This material is based upon work supported by, or in part by, the U.S. Army Research Laboratory and the U.S. Army Research Office under contract/grant number 40473-MA

A compositional monitoring framework for hard real-time systems

Runtime Monitoring of hard real-time embedded systems is a promising technique for ensuring that a running system respects timing constraints, possibly combined with faults originated by the software and/or hardware. This is particularly important when we have real-time embedded systems made of several components that must combine different levels of criticality, and different levels of correctness requirements. This paper introduces a compositional monitoring framework coupled with guarantees that include time isolation and the response time of a monitor for a predicted violation. The kind of monitors that we propose are automatically generated by synthesizing logic formulas of a timed temporal logic, and their correctness is ensured by construction.This work was partially supported by National Funds through FCT (Portuguese Foundation for Science and Technology) and by ERDF (European Regional Development Fund) through COMPETE (Operational Programme ’Thematic Factors of Competitiveness’), within projects Ref. FCOMP-01-0124-FEDER-022701 (CISTER), FCOMP-01-0124- FEDER-015006 (VIPCORE) and FCOMP-01-0124-FEDER-020486 (AVIACC)

Replication for Web Hosting Systems

Replication is a well-known technique to improve the accessibility of Web sites. It generally offers reduced client latencies and increases a site’s availability. However, applying replication techniques is not trivial, and various Content Delivery Networks (CDNs) have been created to facilitate replication for digital content providers. Th