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Qi Liu

Qi Liu
IBM · Thomas J. Watson Research Center

PhD in Electrical and Computer Engineering

About

19
Publications
4,154
Reads
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300
Citations
Citations since 2016
0 Research Items
130 Citations
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20162017201820192020202120220510152025

Publications

Publications (19)
Article
Full-text available
This work attempts to provide insight into the problem of executing discrete event simulation in a distributed fashion. The article serves as the state of the art in Parallel Discrete-Event Simulation (PDES) by surveying existing algorithms and analyzing the merits and drawbacks of various techniques. We discuss the main characteristics of existing...
Conference Paper
To address the challenge of automated performance benchmarking in virtualized cloud infrastructures, an extensible and adaptable framework called CloudBench has been developed to conduct scalable, controllable, and repeatable experiments in such environments. This paper presents the hardware-in-the-loop simulation technique used in CloudBench, whic...
Conference Paper
The increasing scale and complexity of virtualized data centers pose significant challenges to system management software stacks, which still rely on special-purpose controllers to optimize the operation of cloud infrastructures. Autonomic computing allows complex systems to assume much of their own management, achieving self-configuration, self-op...
Conference Paper
Full-text available
Traffic simulation can be very computationally intensive, especially for microscopic simulations of large urban areas (tens of thousands of road segments, hundreds of thousands of agents) and when real-time or better than real-time simulation is required. For instance, running a couple of what-if scenarios for road management authorities/police dur...
Article
Parallel discrete-event simulation on heterogeneous multicore platforms requires innovative redesign of existing algorithms in return for better performance. Based on the Discrete Event System Specification (DEVS) methodology, a technique called Multicore Acceleration of DEVS Systems is proposed for efficient parallel discrete-event simulation on t...
Conference Paper
The growth in the adoption of cloud computing is driven by distinct and clear benefits for both cloud customers and cloud providers. However, the increase in the number of cloud providers as well as in the variety of offerings from each provider has made it harder for customers to choose. At the same time, the number of options to build a cloud inf...
Conference Paper
Full-text available
This paper presents a new technique for efficient parallel simulation of large-scale DEVS-based models on the IBM Cell processor, which has one Power Processing Element (PPE) and eight Synergistic Processing Elements (SPEs). By taking a performance-centered approach, the technique allows for exploitation of multi-dimensional parallelism to overcome...
Conference Paper
Full-text available
This paper presents a computing technique for efficient parallel simulation of large-scale discrete-event models on the IBM Cell Broadband Engine (CBE), which has one Power Processor Element (PPE) and eight Synergistic Processing Elements (SPE). Based on the general-purpose Discrete Event System Specification (DEVS), the technique tackles all perfo...
Conference Paper
Full-text available
We propose a computing technique for efficient parallel simulation of compute-intensive DEVS models on the IBM Cell processor, combining multi-grained parallelism and various optimizations to speed up the event execution. Unlike most existing parallelization strategies, our approach explicitly exploits the massive fine-grained event-level paralleli...
Article
Full-text available
Cellular automata were designed by John von Neumann in the 1940s, as a mathematical abstraction for modeling self-replicating algorithms. Since then, cellular automata have been widely studied theoretically and evolved into multiple variants. In the 1970s, Bernard P. Zeigler proposed a formalism rooted on systems theory principles, named DEVS (disc...
Conference Paper
Full-text available
The Lightweight Time Warp (LTW) protocol offers a novel approach to high-performance optimistic parallel discrete-event simulation, especially when a large number of simultaneous events need to be executed at each virtual time. With LTW, the local simulation space on each node is partitioned into two sub-domains, allowing purely optimistic simulati...
Article
Full-text available
We introduce advanced graphical modeling and visualization facilities for Discrete Event System Specification (DEVS) modeling and simulation (M&S) in the CD++ environment. The objective is to provide general users with a variety of easy-to-use environments to facilitate the model analysis process and thereby promoting the adoption of M&S by a wider...
Conference Paper
Full-text available
This paper proposes a novel Lightweight Time Warp (LTW) protocol for high-performance parallel optimistic simulation of large-scale DEVS and Cell- DEVS models. By exploiting the characteristics of t he simulation process, the protocol is able to set fre e most logical processes (LPs) from the Time Warp mechanism , while the overall simulation still...
Conference Paper
Full-text available
The emergence of recent XML-based technologies paved the way for new types of architectures and message exchanges on the Internet through Web services. Mash-ups consist of combining existing systems capabilities in order to create new added value services. This paper focuses on a mash-up of different Web services that can be used by emergency plann...
Conference Paper
Full-text available
This paper presents a case study of Web-based distributed simulation across the Atlantic Ocean between Canada and France. The distributed simulation engine, known as DCD++, extends the CD++ environment to expose the simulation functionalities as machine- consumable services based on the DEVS and Cell-DEVS formalisms and commonly-used Web Service te...
Conference Paper
Full-text available
The growing popularity of Networks of Workstations (NOW) in scientific computation has drawn increasing interest from the M&S community. This paper addresses the issue of parallel discrete-event simulation of DEVS and Cell-DEVS models on a Microsoft Windows-based cluster system comprising interconnected general-purpose personal computers. We presen...
Article
Full-text available
Discrete Event System Specification (DEVS) is a sound formalism to describe generic dynamic systems in a hierarchical and modular way. Cell-DEVS is a DEVS-based formalism intended to model compleX physical systems as cell spaces. This work presents new techniques for eXecuting DEVS and Cell-DEVS models in parallel and distributed environments based...
Conference Paper
Full-text available
DEVS is a formalism to describe generic dynamic systems in a hierarchical and modular way. We present new techniques for executing DEVS and Cell-DEVS models in parallel and distributed environments based on the warped kernel. The parallel simulator PCD++ has been extended to support optimistic simulations. A non-hierarchical approach is employed to...
Conference Paper
Full-text available
CD++ is an implementation of the Cell-DEVS formalism, which has been used to simulate various complex systems. In this study, we constructed a Cell-DEVS to simulate the dynamics of a dual market. Using new features of CD++, we obtained accurate results taking into account consumers' purchasing history. The resulting model allows fast execution, eas...

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