Scott A. Hissam

AGORA: a search engine for software components

Using JavaBeans and CORBA agents in conjunction with Web search technologies, this prototype search engine (Agora), automatically generates and indexes a worldwide database of software products, classified by component model. Users of Agora can search for components in this database by describing specific properties of a components interface. The system combines Web search engines with an introspection process. Introspection, primarily associated with JavaBeans, describes the capability of components to provide information about their own interfaces. The Common Object Request Broker Architecture offers a similar capability, although this data is maintained external to the CORBA server in an interface repository.

Complex COTS-based software systems: practical steps for their maintenance

This paper makes pragmatic recommendations for the maintenance of complex COTS-based systems. We first enumerate the issues that can arise in systems that rely on COTS products, whether in operational systems themselves or in the support systems used to create, modify, or test operational systems. We then suggest principles by which maintenance practice for such systems can be facilitated, particularly for those safety-critical systems for which significant risk is present if they fail. These principles aim at making explicit, during system creation, the COTS-related development practices upon which successful system maintenance will subsequently depend. They also depend on a reasonable means of determining, during system maintenance, how much risk is acceptable in using new releases of COTS products. Copyright

Isolating faults in complex COTS-based systems

Abstract : This monograph provides an overview of a method for isolating and overcoming faults in COTS-based systems. It provides a method and mechanisms that are useful for engineers and integrators who are tasked with assembling complex systems from heterogeneous sources. While other readers may find value in this report, it is specifically written for a technical audience. The method described in this monograph has been used on various systems. One such use is described in the SEI monograph Case Study: Correcting System Failure in a COTS Information System.

Custom vs. off-the-shelf architecture

Members of the COTS-based system initiative at the Software Engineering Institute have developed the Generic Enterprise Ensemble (GEE), a generic approach to building distributed, transaction based, secure enterprise information systems (EIS). GEE is a tool to help in the selection of technologies and architectural choices when building enterprise information systems. Enterprise JavaBeans/sup TM/ (EJB) is a specification from Sun Microsystems for an application server based on Java technology. a comparison is made between GEE based solutions and off-the-shelf solutions based on the EJB specification.

Experience report: correcting system failure in a COTS information system

This paper provides an in-depth technical study about a COTS-based information system made up of several commercial components. In particular, this paper provides detail on the activities needed to make the system functionally useful. While all readers may find value in this report, it is expressly aimed at a technical audience. The organization that performed the work described herein is not named, nor are the specific commercial products. All of them, however, are common products, and the work is very typical of the type of effort that integrating and tuning a COTS-based information system can entail.

Predictability by construction

The Predictable Assembly from Certifiable Components (PACC) team at the Software Engineering Institute has developed a vehicle to create component-based systems that have predictable behavior prior to implementation. The project has been used to successfully predict performance and safety properties of real-time systems, but the concepts and technology can be applied to predict other properties (e.g., reliability, security).

Predicting the Behavior of a Highly Configurable Component Based Real-Time System

Software components and the technology supporting component based software engineering contribute greatly to the rapid development and configuration of systems for a variety of application domains. Such domains go beyond desktop office applications and information systems supporting e-commerce, but include systems having real-time performance requirements and critical functionality. Discussed in this paper are the results from an experiment that demonstrates the ability to predict deadline satisfaction of threads in a real-time system where the functionality performed is based on the configuration of the assembled software components. Presented is the method used to abstract the large, legacy code base of the system software and the application software components in the system; the model of those abstractions based on available architecture documentation and empirically-based, runtime observations; and the analysis of the predictions which yielded objective confidence in the observations and model created which formed the underlying basis for the predictions.

High Assurance for Distributed Cyber Physical Systems

Distributed Adaptive Real-Time (DART) systems are interconnected and collaborating systems that continuously must satisfy guaranteed and highly critical requirements (e.g., collision avoidance), while at the same time adapt, smartly, to achieve best-effort and low-critical application requirements (e.g., protection coverage) when operating in dynamic and uncertain environments. This short paper introduces our architecture and approach to engineering a DART system so that we achieve high assurance in its runtime behavior against a set of formally specified requirements. It describes our technique to: (i) ensure asymmetric timing protection between high- and low-critical threads on each node in the DART system, and (ii) verify that the self-adaptation within, and coordination between, the nodes and their interaction with the physical environment do not violate high and low criticality requirements. We present our ongoing research to integrate advances in model-based engineering with compositional analysis techniques to formally verify safety-critical properties demanded in safety-conscious domains such as aviation and automotive; and introduce our DART model problem to demonstrate of our engineering approach.

Adaptive Quality of Service in ad hoc wireless networks

In high criticality crisis scenarios, such as disaster management, ad hoc wireless networks are quickly assembled in the field to support decision makers through situational awareness using messaging-, voice-, and video-based applications. These applications cannot afford the luxury of stalling or failing due to overwhelming bandwidth demand on these networks as this could contribute to overall mission failure. This paper describes an approach for satisfying application-specific Quality of Service (QoS) expectations operating on ad hoc wireless networks where available bandwidth fluctuates. The proposed algorithm, D-Q-RAM (Distributed QoS Resource Allocation Model) incorporates a distributed optimization heuristic that results in near optimal adaptation without the need to know, estimate, or predict available bandwidth at any moment in time.

Browsers for distributed systems: Universal paradigm or siren’s song?

Web‐based browsers are quickly becoming ubiquitous in the workplace. Software development managers are quick to incorporate browsers into a broad range of software development projects, often inappropriately. The purpose of this paper is to examine the technical issues relevant to incorporating browsers as a component of a commercial off‐the‐shelf (COTS)‐based solution. Issues examined include portability, performance, functionality, security, human factors, distribution, installation, upgrading, component‐based development, runtime configuration management, and licensing.