7872163
Closed and Logical Relations for Over- and Under-Approximation of Powersets
We redevelop and extend Dams’s results on over- and under-approximation with higher-order Galois connections:
42747855
Action Semantics-Directed Prototyping
We present a methodology for compiler synthesis based on Mosses-Watt's action semantics. Each action in action semantics notation is assigned specific ''analysis functions'', such as a typing function and a binding-time function. When a language is given an action semantics, the typing and binding-time functions for the individual actions compose into typing and binding-time analyses for the language; these are implemented as the type checker and static semantics processor, respectively, in the synthesized compiler. Other analyses can be similarly formalized and implemented. We show a sample language semantics and its synthesized compiler, and we describe the compiler synthesizer that we have developed.
11623434
Evaluating real-time Java features and performance for real-time embedded systems
This paper provides two contributions to the study of programming languages and middleware for real-time and embedded applications. First, we present the empirical results from applying the RTJPerf benchmarking suite to evaluate the efficiency and predictability of several implementations of the real-time specification for Java (RTSJ). Second, we describe some of the techniques used to develop jRate, which is an open-source ahead-of-time-compiled implementation of RTSJ we are developing. Our results indicate that RTSJ implementations are maturing to the point where they can be applied to a variety of real-time embedded applications.
10026978
Modularizing variability and scalability concerns in distributed real-time and embedded systems with modeling tools and component middleware
Developing real-time software for large-scale distributed real-time and embedded (DRE) systems is hard due to variabilities that arise from (I) integration with various subsystems based on different programming languages and hardware, OS, middleware platforms, (2) fine tuning the system to satisfy a range of customer requirements, such as various quality-of-service (QoS) properties, and (3) changing functional and QoS properties of the system based on available system resources. This paper describes our experience applying model-driven development (MDD) tools and QoS-enabled component middleware technologies to address domain- and middleware-specific variability challenges in an inventory tracking system, which manages the storage and flow of items in warehouses. Our results show that (I) coherent integration of MDD tools and component middleware can provide a productive software process for developing DRE systems by modularizing and composing variability concerns and (2) significant challenges remain that must be overcome to apply these technologies to a broader range of DRE systems
8977671
A flexible image search engine
ndessaig 63 ireste.fr Multimedia searching over Internet has gained substantial popularity in the past two years. Java’s networking features, along with the growing number of Web browsers that can execute Java apple&, facilitate distributed processing. Networking and computational performances are key concerns when considering the use of Java to develop performancesensitive distributed multimedia search engines. This paper describes MISE, the MediaSys Image Search Engine over a large-scale network. After an overview of the architecture, we present the search capabilities of MISE as companion part of image processing.
1561734
The Design and Performance of a Real-Time CORBA Scheduling Service
There is increasing demandto extend CORBA middleware to support applications with stringentquality of service (QoS) requirements. However, conventionalCORBA middleware does not define standard features to dynamicallyschedule operations for applications that possess deterministicreal-time requirements. This paper presents three contributionsto the study of real-time CORBA operation scheduling strategies.First, we document our evolution from static to dynamic schedulingfor applications with deterministic real-time requirements. Second,we describe the flexible scheduling service framework in ourreal-time CORBA implementation, TAO, which supports core schedulingstrategies efficiently. Third, we present results from empiricalbenchmarks that quantify the behavior of these scheduling strategiesand assess the overhead of dynamic scheduling in TAO. Our empiricalresults using TAO show that dynamic scheduling of CORBA operationscan be deterministic and can achieve acceptable latency for operations,even with moderate levels of queueing.
2571822
Towards Real-Time Fault-Tolerant CORBA Middleware
An increasing number of applications are being developed using Distributed Object Computing (DOC) middleware, such as CORBA. Many of these applications require the underlying middleware, operating systems, and networks to provide dependable end-to-end Quality of Service (QoS) support to enhance their efficiency, predictability, scalability, and reliability. The Object Management Group (OMG), which standardizes CORBA, has addressed many of these application requirements individually in the Real-Time CORBA (RT-CORBA) and Fault-Tolerant CORBA (FT-CORBA) specifications. Though the implementations of RT-CORBA are suitable for mission-critical commercial or military distributed Real-Time and Embedded (DRE) systems, the usage of FT-CORBA with RT-CORBA implementations are not yet suitable for systems that have stringent simultaneous dependability and predictability requirements.This paper provides three contributions to the study and evaluation of dependable CORBA middleware for performance-sensitive DRE systems. First, we provide an overview of FT-CORBA and illustrate the sources of unpredictability associated with conventional FT-CORBA implementations. Second, we discuss the QoS requirements of an important class of mission-critical DRE systems to show how these requirements are not well served by FT-CORBA today. Finally, we empirically evaluate new dependability strategies for FT-CORBA that can help make the use of DOC middleware for mission-critical DRE systems a reality.