Search For:

Displaying 1-50 out of 50 total
Keynote
Found in: 2012 IEEE 33rd Real-Time Systems Symposium (RTSS 2012)
By Edward A. Lee
Issue Date:December 2012
pp. xiii
Summary form only given. All widely used software and networking abstractions lack temporal semantics. The notion of correct execution of a program written in every widely-used programming language, in nearly every processor instruction-set, and the most w...
   
A Heterogeneous Architecture for Evaluating Real-Time One-Dimensional Computational Fluid Dynamics on FPGAs
Found in: Field-Programmable Custom Computing Machines, Annual IEEE Symposium on
By Isaac Liu,Edward A. Lee,Matthew Viele,Guoqiang Wang,Hugo Andrade
Issue Date:May 2012
pp. 125-132
Many fuel systems for diesel engines are developed with the help of commercial one-dimensional computational fluid dynamics (1D CFD) solvers that model and simulate the behavior of fluid flow through the interconnected pipes off-line. This paper presents a...
 
Cyber Physical Systems: Design Challenges
Found in: Object-Oriented Real-Time Distributed Computing, IEEE International Symposium on
By Edward A. Lee
Issue Date:May 2008
pp. 363-369
Cyber-Physical Systems (CPS) are integrations of computation and physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops where physical processes affect computations and vice versa. The ec...
 
Counting Interface Automata and their Application in Static Analysis of Actor Models
Found in: Software Engineering and Formal Methods, IEEE International Conference on
By Ernesto Wandeler, Jorn W. Janneck, Edward A. Lee, Lothar Thiele
Issue Date:September 2005
pp. 106-116
We present an interface theory based approach to static analysis of actor models. We first introduce a new interface theory, which is based on Interface Automata, and which is capable of counting with numbers. Using this new interface theory, we can captur...
 
Hierarchical Concurrent Finite State Machines in Ptolemy
Found in: Application of Concurrency to System Design, International Conference on
By Bilung Lee, Edward A. Lee
Issue Date:March 1998
pp. 34
We implement a finite state machine (FSM) domain for specifying and simulating control functionality of a system within the Ptolemy software environment. The FSM domain is successfully integrated with synchronous dataflow (SDF) and discrete-event (DE) conc...
 
A PRET microarchitecture implementation with repeatable timing and competitive performance
Found in: 2012 IEEE 30th International Conference on Computer Design (ICCD 2012)
By Isaac Liu,Jan Reineke,David Broman,Michael Zimmer,Edward A. Lee
Issue Date:September 2012
pp. 87-93
We contend that repeatability of execution times is crucial to the validity of testing of real-time systems. However, computer architecture designs fail to deliver repeatable timing, a consequence of aggressive techniques that improve average-case performa...
 
PtidyOS: A Lightweight Microkernel for Ptides Real-Time Systems
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Jia Zou,Slobodan Matic,Edward A. Lee
Issue Date:April 2012
pp. 209-218
Ptides, a programming model for distributed real-time embedded systems, was proposed previously. In this work, we focus on a work flow that applies Ptides in a single-CPU environment using model-based design techniques. Our work flow starts with a programm...
 
Deploying Hard Real-Time Control Software on Chip-Multiprocessors
Found in: Real-Time Computing Systems and Applications, International Workshop on
By Dai N. Bui, Hiren D. Patel, Edward A. Lee
Issue Date:August 2010
pp. 283-292
Deploying real-time control systems software on multiprocessors requires distributing tasks on multiple processing nodes and coordinating their executions using a protocol. One such protocol is the discrete-event (DE) model of computation. In this paper, w...
 
Toward the Design of Robotic Software with Verifiable Safety
Found in: Computer Software and Applications Conference, Annual International
By Chih-Hong Cheng, Markus Rickert, Christian Buckl, Edward A. Lee, Alois Knoll
Issue Date:July 2009
pp. 622-623
In this report, we mention some challenges and preliminary solutions toward designing robotic software with verifiable safety.
 
The Case for Timing-Centric Distributed Software
Found in: Distributed Computing Systems Workshops, International Conference on
By Edward A. Lee, Slobodan Matic, Sanjit A. Seshia, Jia Zou
Issue Date:June 2009
pp. 57-64
This paper makes the case that the time is right to introduce temporal semantics into programming models for cyber-physical systems. Specifically, we argue for a programming model called PTIDES that provides a coordination language rooted in discreteevent ...
 
Execution Strategies for PTIDES, a Programming Model for Distributed Embedded Systems
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Jia Zou, Slobodan Matic, Edward A. Lee, Thomas Huining Feng, Patricia Derler
Issue Date:April 2009
pp. 77-86
We define a family of execution policies for a programming model called PTIDES (Programming Temporally Integrated Distributed Embedded Systems). A PTIDES application (factory automation, for example) is given as a discrete-event (DE) model of a distributed...
 
An Automated Mapping of Timed Functional Specification to a Precision Timed Architecture
Found in: Distributed Simulation and Real Time Applications, IEEE/ACM International Symposium on
By Shanna-Shaye Forbes, Hiren D. Patel, Edward A. Lee, Hugo A. Andrade
Issue Date:October 2008
pp. 322-325
Most common real-time embedded programming languages provide a means to specify functionality; however, they have few constructs to specify precise timing constraints. LabVIEW is one example of a graphical programming language that supports timing specific...
 
Simulation and Implementation of the PTIDES Programming Model
Found in: Distributed Simulation and Real Time Applications, IEEE/ACM International Symposium on
By Patricia Derler, Edward A. Lee, Slobodan Matic
Issue Date:October 2008
pp. 330-333
We have previously proposed PTIDES (Programming Temporally Integrated Distributed Embedded Systems), a discrete-event framework that binds realtime with model time at sensors, actuators, and network interfaces. In this experimental effort we focus on perfo...
 
Time is a Resource, and Other Stories
Found in: Object-Oriented Real-Time Distributed Computing, IEEE International Symposium on
By Edward A. Lee
Issue Date:May 2008
pp. 355
This paper examines some misleading aphorisms.
   
Real-Time Distributed Discrete-Event Execution with Fault Tolerance
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Thomas Huining Feng, Edward A. Lee
Issue Date:April 2008
pp. 205-214
We build on PTIDES, a programming model for distributed embedded systems that uses discrete-event (DE) models as program specifications. PTIDES improves on distributed DE execution by allowing more concurrent event processing without backtracking. This pap...
 
A Programming Model for Time-Synchronized Distributed Real-Time Systems
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Yang Zhao, Jie Liu, Edward A. Lee
Issue Date:April 2007
pp. 259-268
Discrete-event (DE) models are formal system specifications that have analyzable deterministic behaviors. Using a global, consistent notion of time, DE components communicate via time-stamped events. DE models have primarily been used in performance modeli...
 
The Problem with Threads
Found in: Computer
By Edward A. Lee
Issue Date:May 2006
pp. 33-42
For concurrent programming to become mainstream, we must discard threads as a programming model. Nondeterminism should be judiciously and carefully introduced where needed, and it should be explicit in programs.
 
Absolutely Positively on Time: What Would It Take?
Found in: Computer
By Edward A. Lee
Issue Date:July 2005
pp. 85-87
For embedded computing to realize its full potential, the author challenges researchers to develop methodologies that will ensure that the systems they design will operate on time.
 
CMOS High-Speed I/Os - Present and Future
Found in: Computer Design, International Conference on
By M.-J. Edward Lee, William J. Dally, Ramin Farjad-Rad, Hiok-Tiaq Ng, Ramesh Senthinathan, John Edmondson, John Poulton
Issue Date:October 2003
pp. 454
High-speed I/O circuits, once used only for PHYs, are now widely used for intra-system signaling as well because of their bandwidth, power, area, and cost advantages. This technology enables chips with over 1 Tb/s of I/O bandwidth today and over 10 Tb/s of...
 
The Ptolemy II Framework for Visual Languages
Found in: Human-Centric Computing Languages and Environments, IEEE CS International Symposium on
By Xiaojun Liu, Yuhong Xiong, Edward A. Lee
Issue Date:September 2001
pp. 50
This paper presents the Ptolemy II framework that supports the visual modeling and design of heterogeneous systems. Models in this framework are structured as hierarchical clustered graphs. The framework provides the infrastructure to support the implement...
   
What's Ahead for Embedded Software?
Found in: Computer
By Edward A. Lee
Issue Date:September 2000
pp. 18-26
<p>Most of today's gadgets and cars use embedded software, which in many cases has taken over what mechanical and dedicated electronic systems used to do. Indeed, embedded software appears in everything from telephones and pagers to systems for medic...
 
Engineering an Education for the Future
Found in: Computer
By Edward A. Lee, David G. Messerschmitt
Issue Date:January 1998
pp. 77-85
<p>Faced with rapid and unremitting change in the disciplines of electrical and computer engineering (ECE), some educators argue that they should deliberately not respond aggressively. Rather, educators should focus on fundamentals that will serve th...
 
Compile-Time Scheduling of Dynamic Constructs in Dataflow Program Graphs
Found in: IEEE Transactions on Computers
By Soonhoi Ha, Edward A. Lee
Issue Date:July 1997
pp. 768-778
<p><b>Abstract</b>—Scheduling dataflow graphs onto processors consists of assigning actors to processors, ordering their execution within the processors, and specifying their firing time. While all scheduling decisions can be made at runt...
 
Self-Timed Resynchronization: A Post-Optimization for Static Multiprocessor Schedules
Found in: Parallel Processing Symposium, International
By Shuvra S. Bhattacharyya, Sundararajan Sriram, Edward A. Lee
Issue Date:April 1996
pp. 199
In a shared-memory multiprocessor system, it is possible that certain synchronization operations are redundant - that is, their corresponding sequencing requirements are enforced completely by other synchronizations in the system - and can be eliminated wi...
 
A Hierarchical Multiprocessor Scheduling System for DSP Applications
Found in: Asilomar Conference on Signals, Systems and Computers
By Jose Luis Pino, Edward A. Lee, Shuvra S. Bhattacharyya
Issue Date:November 1995
pp. 122
This paper discusses a hierarchical scheduling framework which reduces the complexity of scheduling synchronous datajow (SDF) graphs onto multiple processors. The core of this framework is a clustering algorithm that decreases the number of nodes before ex...
 
Minimizing Synchronization Overhead in Statically Scheduled Multiprocessor Systems
Found in: Application-Specific Systems, Architectures and Processors, IEEE International Conference on
By Shuvra S. Bhattacharyya, Sundararajan Sriram, Edward A. Lee
Issue Date:July 1995
pp. 298
Synchronization overhead can significantly degrade performance in embedded multiprocessor systems. This paper develops techniques to determine a minimal set of processor synchronizations that are essential for correct execution in an embedded multiprocesso...
 
A Hardware-Software Codesign Methodology for DSP Applications
Found in: IEEE Design and Test of Computers
By Asawaree Kalavade, Edward A. Lee
Issue Date:July 1993
pp. 16-28
<p>The authors describe a systematic, heterogeneous design methodology using the Ptolemy framework for simulation, prototyping, and software synthesis of systems containing a mixture of hardware and software components. They focus on signal-processin...
 
Programmable DSPs: A Brief Overview
Found in: IEEE Micro
By Edward A. Lee
Issue Date:September 1990
pp. 14-16
<p>A brief history of digital signal processors (DSPs), which may become the key to the integration of telecommunications and computation, is presented. A tabular summary of models to date is provided. The recent emergence of DSP cores is discussed.&...
 
A Theory of Synchronous Relational Interfaces
Found in: ACM Transactions on Programming Languages and Systems (TOPLAS)
By Ben Lickly, Edward A. Lee, Edward A. Lee, Stavros Tripakis, Stavros Tripakis, Thomas A. Henzinger, Thomas A. Henzinger
Issue Date:July 2011
pp. 1-41
Compositional theories are crucial when designing large and complex systems from smaller components. In this work we propose such a theory for synchronous concurrent systems. Our approach follows so-called interface theories, which use game-theoretic inter...
     
Predictable programming on a precision timed architecture
Found in: Proceedings of the 2008 international conference on Compilers, architectures and synthesis for embedded systems (CASES '08)
By Ben Lickly, Edward A. Lee, Hiren D. Patel, Isaac Liu, Stephen A. Edwards, Sungjun Kim
Issue Date:October 2008
pp. 79-79
In a hard real-time embedded system, the time at which a result is computed is as important as the result itself. Modern processors go to extreme lengths to ensure their function is predictable, but have abandoned predictable timing in favor of average-cas...
     
The case for the precision timed (PRET) machine
Found in: Proceedings of the 44th annual conference on Design automation (DAC '07)
By Edward A. Lee, Stephen A. Edwards
Issue Date:June 2007
pp. 264-265
Patterson and Ditzel [12] did not invent reduced instruction set computers (RISC) in 1980. Earlier computers all had reduced instruction sets. Instead, they argued that trends in computer architecture had gotten off the sweet spot, and that by dropping bac...
     
Ptera: an event-oriented model of computation for heterogeneous systems
Found in: Proceedings of the tenth ACM international conference on Embedded software (EMSOFT '10)
By Edward A. Lee, Lee W. Shruben, Thomas Huining Feng
Issue Date:October 2010
pp. 219-228
Many modeling techniques for embedded systems focus on events that occur in time and the causality relationships between them. Event-oriented modeling complements class-oriented, object-oriented, actor-oriented and state-oriented approaches. To facilitate ...
     
Modeling uncertainty for middleware-based streaming power grid applications
Found in: Proceedings of the 8th Workshop on Middleware for Next Generation Internet Computing (MW4NextGen '13)
By Edward A. Lee, Yan Liu, Ian Gorton, Ilge Akkaya
Issue Date:December 2013
pp. 1-6
The power grid is incorporating high throughput sensor devices into power distribution networks. The future power grid needs to guarantee accuracy and responsiveness of applications that consume data from multiple sensor streams. The end-to-end performance...
     
How we recreated the 2001: A Space Odyssey's star-gate effect for PixelJunk 4am
Found in: ACM SIGGRAPH 2012 Dailies (SIGGRAPH '12)
By Edward Lee
Issue Date:August 2012
pp. 1-1
The Distinguished Artist Award is awarded annually to an artist who has created a substantial and important body of work that significantly advances aesthetic content in the field of digital art. The 2012 recipient of the Distinguished Artist Award is Jean...
     
Model-based specification of timing requirements
Found in: Proceedings of the tenth ACM international conference on Embedded software (EMSOFT '10)
By Alois Knoll, Christian Buckl, Edward A. Lee, Irina Gaponova, Michael Geisinger
Issue Date:October 2010
pp. 239-248
In the past, model-based development focused mainly on functional and structural aspects of the system to be developed. Recently, several approaches to include timing aspects have been suggested. However, these approaches are typically applied in later dev...
     
Exploring models of computation with ptolemy II
Found in: Proceedings of the eighth IEEE/ACM/IFIP international conference on Hardware/software codesign and system synthesis (CODES/ISSS '10)
By Christopher X. Brooks, Edward A. Lee, Stavros Tripakis
Issue Date:October 2010
pp. 331-332
The Ptolemy project studies modeling, simulation, and design of concurrent, real-time, embedded systems. The focus is on assembly of concurrent components. The key underlying principle in the project is the use of well-defined models of computation that go...
     
Modeling and analyzing real-time multiprocessor systems
Found in: Proceedings of the eighth IEEE/ACM/IFIP international conference on Hardware/software codesign and system synthesis (CODES/ISSS '10)
By Edward A. Lee, Lothar Thiele, Maarten Wiggers, Marco Bekooij, Simon Schliecker
Issue Date:October 2010
pp. 329-330
Approaches have been developed to verify that real-time multi-processor systems meet their timeliness constraints. Such approaches make assumptions on the model of computation, the load placed on the multi-processor system, and the faults that can arise. T...
     
CPS foundations
Found in: Proceedings of the 47th Design Automation Conference (DAC '10)
By Edward A. Lee
Issue Date:June 2010
pp. 737-742
This paper argues that cyber-physical systems present a sub-stantial intellectual challenge that requires changes in both theories of computation and dynamical systems theory. The CPS problem is not the union of cyber and physical problems, but rather thei...
     
Introducing embedded systems: a cyber-physical approach: extended abstract
Found in: Proceedings of the 2009 Workshop on Embedded Systems Education (WESS '09)
By Edward A. Lee
Issue Date:October 2009
pp. 1-2
I suggest that embedded systems education should focus more on the interplay of embedded systems and the physical environment in which they operate, rather than on the collection of software and hardware technologies needed to get computers to interact wit...
     
On relational interfaces
Found in: Proceedings of the seventh ACM international conference on Embedded software (EMSOFT '09)
By Ben Lickly, Edward A. Lee, Stavros Tripakis, Thomas A. Henzinger
Issue Date:October 2009
pp. 67-76
In this paper we extend the work of Alfaro, Henzinger et al. on interface theories for component-based design. Existing interface theories often fail to capture functional relations between the inputs and outputs of an interface. For example, a simple sync...
     
Classes and inheritance in actor-oriented design
Found in: ACM Transactions on Embedded Computing Systems (TECS)
By Edward A. Lee, Stephen Neuendorffer, Xiaojun Liu
Issue Date:July 2009
pp. 1-26
Actor-oriented components emphasize concurrency and temporal semantics and are used for modeling and designing embedded software and hardware. Actors interact with one another through ports via a messaging schema that can follow any of several concurrent s...
     
PTIDES on flexible task graph: real-time embedded systembuilding from theory to practice
Found in: Proceedings of the 2009 ACM SIGPLAN/SIGBED conference on Languages, compilers, and tools for embedded systems (LCTES '09)
By David F. Bacon, Edward A. Lee, Jia Zou, Joshua Auerbach
Issue Date:June 2009
pp. 83-92
The Flexotask system claims to enable implementation of both real-time applications and real-time schedulers in a Java Virtual Machine using an actors-like model. The PTIDES model is an actors-like model that claims to deliver precise control over end-to-e...
     
Computing needs time
Found in: Communications of the ACM
By Edward A. Lee
Issue Date:May 2009
pp. 101-104
The passage of time is essential to ensuring the repeatability and predictability of software and networks in cyber-physical systems.
     
Branch-on-random
Found in: Proceedings of the sixth annual IEEE/ACM international symposium on Code generation and optimization (CGO '08)
By Craig Zilles, Edward Lee
Issue Date:April 2008
pp. 49-54
We propose a new instruction, branch-on-random, that is like a standard conditional branch, except rather than specifying the condition on which the branch should be taken, it specifies a frequency at which the branch should be taken. We show that branch-o...
     
Causality interfaces for actor networks
Found in: ACM Transactions on Embedded Computing Systems (TECS)
By Edward A. Lee, Ye Zhou
Issue Date:April 2008
pp. 1-35
We consider concurrent models of computation where “actors” (components that are in charge of their own actions) communicate by exchanging messages. The interfaces of actors principally consist of “ports,” which mediate the exchange...
     
A causality interface for deadlock analysis in dataflow
Found in: Proceedings of the 6th ACM & IEEE International conference on Embedded software (EMSOFT '06)
By Edward A. Lee, Ye Zhou
Issue Date:October 2006
pp. 44-52
In this paper, we consider a concurrent model of computation called dataflow, where components (actors) communicate via streams of data tokens. Dataflow semantics has been adopted by experimental and production languages used to design embedded systems. Th...
     
A code generation framework for Java component-based designs
Found in: Proceedings of the international conference on Compilers, architectures, and synthesis for embedded systems (CASES '00)
By Christopher Hylands, Edward Lee, Jeff Tsay
Issue Date:November 2000
pp. 18-25
Existing CHI interaction models are focused on understanding the needs of users. They begin with user tasks and user feedback. While the involvement of users is critical for human computer interaction development, so is the imagination the artist-scientist...
     
Embedded systems education (panel session) (abstract only)
Found in: Proceedings of the 37th conference on Design automation (DAC '00)
By Alberto Sangiovanni-Vincentelli, D. K. Arvind, Edward Lee, Phil Koopman, Sharad Malik, Wayne Wolf
Issue Date:June 2000
pp. 519
The design and design automation of embedded systems is rapidly emerging as a research area in its own right. It draws from several traditional areas of study such as system specification, modeling and analysis; computer architecture and micro-architecture...
     
Manifestations of heterogeneity in hardware/software co-design
Found in: Proceedings of the 31st annual conference on Design automation conference (DAC '94)
By Asawaree Kalavadee, Edward A. Lee
Issue Date:June 1994
pp. 437-438
A new gridless router accelerated by Content Addressable Memory (CAM) is presented. A gridless version of the line-expansion algorithm is implemented, which always finds a path if one exists. The router runs in linear time by means of the CAM-based acceler...
     
A component-based approach to modeling and simulating mixed-signal and hybrid systems
Found in: ACM Transactions on Modeling and Computer Simulation (TOMACS)
By Edward A. Lee, Jie Liu
Issue Date:January 1991
pp. 343-368
Systems with both continuous and discrete behaviors can be modeled using a mixed-signal style or a hybrid systems style. This article presents a component-based modeling and simulation framework that supports both modeling styles. The component framework, ...
     
 1