Lui R. Sha

Software Engineering Institute

Publications by Lui R. Sha

Risk Detection and Mitigation Metrics and Design Check Lists for Real Time and Embedded Systems

April 19, 2009 • White Paper

Doug Locke Lui R. Sha

A whitepaper by Lui Sha of the University of Illinois and C. Douglass Locke of LC System Services Inc. The paper discusses risk detection and mitigation metrics and design check lists for real time and embedded systems.
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Results of SEI Independent Research and Development Projects (FY 2008)

December 01, 2008 • Technical Report

Dionisio de Niz Gabriel Moreno Robert Nord

This report describes the independent research and development (IRAD) projects that were conducted during fiscal year 2008 (October 2007 through September 2008).
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Results of SEI Independent Research and Development Projects (FY 2007)

July 01, 2008 • Technical Report

Len Bass Lui R. Sha Dennis B. Smith

This report describes the independent research and development (IRAD) projects that were conducted during fiscal year 2007 (October 2006 through September 2007).
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QUASAR: A Method for the Quality Assessment of Software-Intensive System Architectures

July 01, 2006 • Handbook

Donald Firesmith Peter Capell Joseph P. Elm

This 2006 handbook documents the QUASAR (QUality Assessment of System ARchitectures) method for assessing the quality of the architecture of a software-intensive system.
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A Case Study on Analytical Analysis of the Inverted Pendulum Real-Time Control System

November 01, 1999 • Technical Report

Danbing Seto Lui R. Sha

An inverted pendulum has been used as the controlled device in a prototype real-time control system employing the Simplex architecture. In this report, we address the control issues of such a system in an analytic way.
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Simplex in a Hostile Communications Environment: The Coordinated Prototype

August 01, 1999 • Technical Report

Neal Altman Charles B. Weinstock Lui R. Sha

This report describes an approach to using Simplex to construct a COTS-based computer system capable of coordinated real-time motion control in a hostile communications environment.
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An Engineering Method for Safety Region Development

August 01, 1999 • Technical Report

Danbing Seto Lui R. Sha

This report studies tolerance of semantic faults, one of the crucial issues in the Simplex architecture.
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An Architectural Description of the Simplex Architecture

March 01, 1996 • Technical Report

JoseGermanRivera AlejandroAndresDanylyszyn Charles B. Weinstock

This report describes SEI-developed Simplex, a software architecture for dependable and evolvable process-control systems.
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Distributed System Design Using Generalized Rate Monotonic Theory

September 01, 1995 • Technical Report

Lui R. Sha Shirishq S. Sathaye

This 1995 paper reviews the rate monotonic scheduling theory, examines the architectural requirements for the use of the theory, and provides an application example.
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A Software Architecture for Dependable and Evolvable Industrial Computing Systems

July 01, 1995 • Technical Report

Lui R. Sha

This paper gives a brief overview of the underlying technologies of the Simplex architecture, which was developed to support safe and reliable online upgrade of hardware and software components.
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Distributed Real-Time System Design: Theoretical Concepts and Applications

March 01, 1993 • Technical Report

Lui R. Sha Shirishq S. Sathaye

This 1993 paper describes the use of generalized rate monotonic scheduling theory for the design and analysis of a distributed real-time system.
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Analysis of Reservation-Based Dual-Link Networks

June 01, 1992 • Technical Report

Lui R. Sha Shirishq S. Sathaye Jay K. Strosnider

This report outlines a general model of reservation-based dual-link networks to support real-time communication.
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An Application-Level Implementation of the Sporadic Server

September 01, 1991 • Technical Report

Michael Gonzalez Harbour Lui R. Sha

The purpose of this paper is to introduce a sporadic server algorithm that can be implemented as an application-level task, and that can be used when no runtime or operating system level implementation of the sporadic server is available.
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Rate Monotonic Analysis for Real-Time Systems

March 01, 1991 • Technical Report

Lui R. Sha Mark H. Klein John B. Goodenough

In this report, we review important decisions in the development of RMA. Our experience indicates that technology transition considerations should be embedded in the process of technology development from the start, rather than as an afterthought.
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Implementing Sporadic Servers in ADA

May 01, 1990 • Technical Report

Brinkley Sprunt Lui R. Sha

This 1990 paper presents the data structures and algorithms for implementing sporadic servers in real-time systems programmed in ADA.
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Scheduling Sporadic and Aperiodic Events in a Hard Real-Time System

April 01, 1989 • Technical Report

Brinkley Sprunt Lui R. Sha J. Lehoczky

This 1989 report introduces a new algorithm, the Sporadic Server algorithm, which greatly improves response times for soft-deadline aperiodic tasks and can guarantee hard deadlines for both periodic and aperiodic tasks.
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Real-Time Scheduling Theory and ADA

April 01, 1989 • Technical Report

Lui R. Sha John B. Goodenough

This 1989 report reviews important results of a priority-based scheduling theory and discusses implications for the Ada tasking model.
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A Real-Time Locking Protocol

April 01, 1989 • Technical Report

Lui R. Sha Ragunathan Rajkumar Sang Son

This 1989 report examines a priority-driven, two-phase lock protocol called the read- or write-priority ceiling protocol.
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Real-Time Scheduling Theory and ADA (1988)

November 01, 1988 • Technical Report

Lui R. Sha John B. Goodenough

This 1988 report reviews results of a priority-based scheduling theory, illustrates its applications with examples, discusses its implications for the Ada tasking model, and suggests workarounds.
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Mode Change Protocols for Priority-Driven Preemptive Scheduling

November 01, 1988 • Technical Report

Lui R. Sha John B. Goodenough Ragunathan Rajkumar

This 1988 report discusses a protocol for accomplishing mode change in the context of a priority-driven preemptive scheduling environment.
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The Priority Ceiling Protocol: A Method for Minimizing the Blocking of High-Priority ADA Tasks

March 01, 1988 • Special Report

John B. Goodenough Lui R. Sha

The priority ceiling protocol is a new technique that addresses the priority inversion problem. Under the priority ceiling protocol, a high priority task can be blocked at most once by a lower priority task.
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