Ming-Ying Chung - Academia.edu (original) (raw)

Uploads

Papers by Ming-Ying Chung

The Saturation algorithm for symbolic state-space generation, has been a recent break-through in ... more The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive verification of complex systems, in particular globally-asyn-chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo-rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache poli-cies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme a...

The Saturation algorithm for symbolic state-space generation, has been a recent break-through in ... more The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive verification of complex systems, in particular globally-asyn-chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo-rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache poli-cies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme a...

Summary form only given. Stochastic automata networks and generalized stochastic Petri nets are t... more Summary form only given. Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used to model complex Markov systems in a structured "Kronecker" approach. We compare them on a suite of examples using two tools, PEPS and SMART.

18th International Parallel and Distributed Processing Symposium, 2004. Proceedings., 2004

Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used t... more Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used to model complex Markov systems in a structured "Kronecker" approach. We compare them on a suite of examples using two tools, PEPS and SMART.

First International Conference on the Quantitative Evaluation of Systems, 2004. QEST 2004. Proceedings., 2004

Outline • Introduction • Parallel and distributed state-space generation • Background • MDDs enco... more Outline • Introduction • Parallel and distributed state-space generation • Background • MDDs encoding of the state-space • Kronecker encoding of the next state function • Saturation-style fixed point iteration strategy • Saturation NOW (Network of workstation) • MDDs distribution, canonicity, and cache management • Saturation NOW in action • Dynamic memory load balancing • Pairwise memory load balancing dilemmas • Nested memory load balancing approach • Experimental results and conclusions Introduction Saturation NOW Parallel and distributed state-space generation • Formal verification : for quality assurance • Model checking : a, model base, automatic verification approach E. Clarke and E. Emerson. Synthesis of synchronization skeletons for branching time temporal logic, Logic of Programs 1981 • State-space generation : the first step in model checking (memory-intensive)

Proceedings 20th IEEE International Parallel & Distributed Processing Symposium, 2006

Lecture Notes in Computer Science, 2006

Chaining can reduce the number of iterations required for symbolic state-space generation and mod... more Chaining can reduce the number of iterations required for symbolic state-space generation and model-checking, especially in Petri nets and similar asynchronous systems, but requires considerable insight and is limited to a static ordering of the events in the high-level model. We introduce a two-step approach that is instead fine-grained and dynamically applied to the decision diagrams nodes. The first step, based on a precedence relation, is guaranteed to improve convergence, while the second one, based on a notion of node fullness, is heuristic. We apply our approach to traditional breadth-first and saturation state-space generation, and show that it is effective in both cases.

Journal of Logic and Computation, 2011

The Saturation-style fixpoint iteration strategy for symbolic reachability analysis is particular... more The Saturation-style fixpoint iteration strategy for symbolic reachability analysis is particularly effective for globally asynchronous locally synchronous discrete-state systems. However, its inherently sequential nature makes it difficult to parallelize Saturation on a network workstations (NOW). We then propose the idea of using idle workstation time to perform speculative image computations. Since an unrestrained prediction may make excessive use of computational resources, we introduce a history-based approach to dynamically recognize image computation (event firing) patterns and explore only firings that conform to these patterns. In addition, we employ an implicit encoding for the patterns, so that the actual image computation history can be efficiently preserved. Experiments not only show that image speculation works on a realistic model, but also indicate that the use of an implicit encoding together with two heuristics results in a better informed speculation.

Electronic Notes in Theoretical Computer Science, 2006

The saturation strategy for symbolic state-space generation is particularly effective for globall... more The saturation strategy for symbolic state-space generation is particularly effective for globally-asynchronous locally-synchronous systems. A distributed version of saturation, SaturationNOW, uses the overall memory available on a network of workstations to effectively spread the memory load, but its execution is essentially sequential. To achieve true parallelism, we explore a speculative firing prediction, where idle workstations work on predicted future event firing requests. A naïve approach where all possible firings may be explored a priori, given enough idle time, can result in excessive memory requirements. Thus, we introduce a historybased approach for firing prediction that recognizes firing patterns and explores only firings conforming to these patterns. Experiments show that our heuristic improves the runtime and has a small memory overhead.

The Saturation algorithm for symbolic state-space generation is a recent advance in exhaustive ve... more The Saturation algorithm for symbolic state-space generation is a recent advance in exhaustive verification of complex systems, in particular globally-asynchronous/ locally-synchronous systems. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during its highly irregular exploration. A crucial factor in limiting the memory consumption in symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache policies become critical while analyzing large-scale systems using a symbolic approach. In this paper, we develop a garbage collection scheme and several operation cache policies to help the analysis of complex systems. Experiments show that our schemes improve the performance of the original distributed implementation, S m A r T N ow , in terms of both time and memory efficiency.

The Saturation algorithm for symbolic state-space generation, has been a recent break-through in ... more The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive verification of complex systems, in particular globally-asyn-chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo-rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache poli-cies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme a...

The Saturation algorithm for symbolic state-space generation, has been a recent break-through in ... more The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive verification of complex systems, in particular globally-asyn-chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo-rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache poli-cies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme a...

Summary form only given. Stochastic automata networks and generalized stochastic Petri nets are t... more Summary form only given. Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used to model complex Markov systems in a structured "Kronecker" approach. We compare them on a suite of examples using two tools, PEPS and SMART.

18th International Parallel and Distributed Processing Symposium, 2004. Proceedings., 2004

Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used t... more Stochastic automata networks and generalized stochastic Petri nets are the main formalisms used to model complex Markov systems in a structured "Kronecker" approach. We compare them on a suite of examples using two tools, PEPS and SMART.

First International Conference on the Quantitative Evaluation of Systems, 2004. QEST 2004. Proceedings., 2004

Outline • Introduction • Parallel and distributed state-space generation • Background • MDDs enco... more Outline • Introduction • Parallel and distributed state-space generation • Background • MDDs encoding of the state-space • Kronecker encoding of the next state function • Saturation-style fixed point iteration strategy • Saturation NOW (Network of workstation) • MDDs distribution, canonicity, and cache management • Saturation NOW in action • Dynamic memory load balancing • Pairwise memory load balancing dilemmas • Nested memory load balancing approach • Experimental results and conclusions Introduction Saturation NOW Parallel and distributed state-space generation • Formal verification : for quality assurance • Model checking : a, model base, automatic verification approach E. Clarke and E. Emerson. Synthesis of synchronization skeletons for branching time temporal logic, Logic of Programs 1981 • State-space generation : the first step in model checking (memory-intensive)

Proceedings 20th IEEE International Parallel & Distributed Processing Symposium, 2006

Lecture Notes in Computer Science, 2006

Chaining can reduce the number of iterations required for symbolic state-space generation and mod... more Chaining can reduce the number of iterations required for symbolic state-space generation and model-checking, especially in Petri nets and similar asynchronous systems, but requires considerable insight and is limited to a static ordering of the events in the high-level model. We introduce a two-step approach that is instead fine-grained and dynamically applied to the decision diagrams nodes. The first step, based on a precedence relation, is guaranteed to improve convergence, while the second one, based on a notion of node fullness, is heuristic. We apply our approach to traditional breadth-first and saturation state-space generation, and show that it is effective in both cases.

Journal of Logic and Computation, 2011

The Saturation-style fixpoint iteration strategy for symbolic reachability analysis is particular... more The Saturation-style fixpoint iteration strategy for symbolic reachability analysis is particularly effective for globally asynchronous locally synchronous discrete-state systems. However, its inherently sequential nature makes it difficult to parallelize Saturation on a network workstations (NOW). We then propose the idea of using idle workstation time to perform speculative image computations. Since an unrestrained prediction may make excessive use of computational resources, we introduce a history-based approach to dynamically recognize image computation (event firing) patterns and explore only firings that conform to these patterns. In addition, we employ an implicit encoding for the patterns, so that the actual image computation history can be efficiently preserved. Experiments not only show that image speculation works on a realistic model, but also indicate that the use of an implicit encoding together with two heuristics results in a better informed speculation.

Electronic Notes in Theoretical Computer Science, 2006

The saturation strategy for symbolic state-space generation is particularly effective for globall... more The saturation strategy for symbolic state-space generation is particularly effective for globally-asynchronous locally-synchronous systems. A distributed version of saturation, SaturationNOW, uses the overall memory available on a network of workstations to effectively spread the memory load, but its execution is essentially sequential. To achieve true parallelism, we explore a speculative firing prediction, where idle workstations work on predicted future event firing requests. A naïve approach where all possible firings may be explored a priori, given enough idle time, can result in excessive memory requirements. Thus, we introduce a historybased approach for firing prediction that recognizes firing patterns and explores only firings conforming to these patterns. Experiments show that our heuristic improves the runtime and has a small memory overhead.

The Saturation algorithm for symbolic state-space generation is a recent advance in exhaustive ve... more The Saturation algorithm for symbolic state-space generation is a recent advance in exhaustive verification of complex systems, in particular globally-asynchronous/ locally-synchronous systems. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during its highly irregular exploration. A crucial factor in limiting the memory consumption in symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache policies become critical while analyzing large-scale systems using a symbolic approach. In this paper, we develop a garbage collection scheme and several operation cache policies to help the analysis of complex systems. Experiments show that our schemes improve the performance of the original distributed implementation, S m A r T N ow , in terms of both time and memory efficiency.