1214419
On the Axiomatizability of Priority
This paper studies the equational theory of bisimulation equivalence over the process algebra BCCSP extended with the priority operator of Baeten, Bergstra and Klop. It is proven that, in the presence of an infinite set of actions, bisimulation equivalence has no finite, sound, ground-complete equational axiomatization over that language. This negative result applies even if the syntax is extended with an arbitrary collection of auxiliary operators, and motivates the study of axiomatizations using conditional equations. In the presence of an infinite set of actions, it is shown that, in general, bisimulation equivalence has no finite, sound, ground-complete axiomatization consisting of conditional equations over BCCSP. Sufficient conditions on the priority structure over actions are identified that lead to a finite, ground-complete axiomatization of bisimulation equivalence using conditional equations
17432425
Structure analysis for dynamic software architecture
The open and dynamic Internet environment greatly urges software entities that are distributed on different locations to coordinate with each other to accomplish a computing task. Software architecture is applied to abstract the software entities to be components and the coordination between them to be connectors and then a model is extracted as the architecture on which the design, analysis and verification are based. Currently, the notion of dynamic software architectures that can modify their architecture and enact modifications during the system execution has become one of the most active research areas. In this paper, we focus on the dynamic evolution of system structure other than coordination mechanisms (e.g. communication protocols). It is widely recognized that some restrictions should be imposed on the system evolution to ensure that the system structure may remain one style or transform within a scope. These conditions, to a large extent, make the system execute under control as expected.
8665982
Structure analysis for dynamic software architecture based on spatial logic
The requirement for modifying system structure during system execution is specified by dynamic software architectures. The system architecture style should remain one style or transform within a scope so that some constraints need to be imposed on during the system execution. Our work expands such an idea along two directions in the setting of formalism. The first direction is to model the system by a graph-based calculus stressing the structure. The other direction lies in that we tailor spatial logic to be a suitable logic as the system specification for structure. The model and specification are basis for the model checking algorithm that is to verify whether the system evolution satisfies some structure constraints. We invite a master-slave architecture style as a running example from the beginning and throughout the paper to demonstrate our approach. Such work can be seen as the basis of the structure analysis for architectures.
8043922
Intensionality of modal logic for Robust Ambient Calculus
Abstract Computation with mobility becomes a novel distributed computation paradigm with the development of network technology. The calculus of Mobile Ambient is a widely studied formal mechanism for describing both mobile computing and mobile computation. To improve this process calculus, Robust Mobile Ambient is introduced by providing co-actions. This paper deals with the modal logic for finite fragment of this calculus without communication primitives. In details, we compare standard behavioral equivalence with the equivalence induced by the logic (=L) and with the structural congruence. As a result, we prove the intensionality of the logic and at the same time, an axiomatization for = L is given. The authors thank the three referees for many constructive suggestions and comments.
15877902
Tree logic with recursion and model checking algorithm
Semi-structured data plays an increasingly important role in the exchange of information between globally distributed applications, which invokes renewed interests in typed programming languages that can manipulate tree-like data structures. Tree logic, inherited from ambient logic, is introduced as the formal foundation of related programming language and type systems. In this paper, we introduce recursion into such logic system, which can describe the tree data more clearly and concisely. By making a distinction between proposition and predicate, a concise semantics interpretation for our modal logic is given. We also develop a model checking algorithm for the logic without . operator. The correctness of the algorithm is shown. Such work can be seen as the basis of the semi-structured data processing language and more flexible type system.
17905406
On the Markovian Randomized Strategy of Controller for Markov Decision Processes
This paper focuses on the so called controller synthesis problem, which addresses the question of how to limit the internal behavior of a given system implementation to meet its specification, regardless of the behavior enforced by the environment. We consider this problem in the probabilistic setting, where the underlying model has both probabilism and nondeterminism and the nondeterministic choices in some states are assumed to be controllable while the others are under the control of an unpredictable environment. As for the specification, it is defined by probabilistic computation tree logic. We show that under the restriction that the controller exploits only Markovian randomized strategy, the existence of such a controller is decidable, which is done by a reduction to the decidability of first-order theory for reals. This also gives rise to an algorithm which can synthesize the controller if it does exist.
43120543
A simulation study on some heuristics for test suite reduction
In order to test a program, software testers must first define a testing objective. From this a test suite is then constructed. In fact, some subsets of the constructed test suite may still satisfy the same testing objective. Such subsets are referred to as representative sets of the test suite. Finding the optimal representative sets of the test suite reduction problem is known to be NP-complete. Different heuristics, including G, GE, grE and H, have been proposed by different researchers. However, it has been demonstrated that none of these four heuristics are guaranteed to deliver smaller sized representative sets. This paper presents the result of a simulation study of these four heuristics. The aim of the study is to provide application guidelines for choosing the most appropriate heuristic for test suite reduction.
60400
A dynamic programming approach to de novo peptide sequencing via tandem mass spectrometry
Tandem mass spectrometry fragments a large number of molecules of the same peptide sequence into charged molecules of prefix and suffix peptide subsequences and then measures mass/charge ratios of these ions. The de novo peptide sequencing problem is to reconstruct the peptide sequence from a given tandem mass spectral data of k ions. By implicitly transforming the spectral data into an NC-spectrum graph G (V, E) where /V/ = 2k + 2, we can solve this problem in O(/V//E/) time and O(/V/2) space using dynamic programming. For an ideal noise-free spectrum with only b- and y-ions, we improve the algorithm to O(/V/ + /E/) time and O(/V/) space. Our approach can be further used to discover a modified amino acid in O(/V//E/) time. The algorithms have been implemented and tested on experimental data.
305291
Toward an Efficient Column Minimum Degree Code for Symmetric Multiprocessors
Ordering the columns of a nonsymmetric sparse matrix can reduce the fill created in its factorization. Minimum-degree is a popular heuristic for ordering symmetric matrices; a variant that can be used to order nonsymmetric matrices is called column minimum degree. In this paper we describe the design of a multithreaded approximate column minimum degree code. We present a framework for the algorithm, study potential sources of parallel inefficiency, and describe our attempts to circumvent the obstacles. We present experimental results that support our analysis.
11068219
An approximation algorithm for haplotype inference by maximum parsimony
This paper studies haplotype inference by maximum parsimony using population data. We define the optimal haplotype inference (OHI) problem as given a set of genotypes and a set of related haplotypes, find a minimum subset of haplotypes that can resolve all the genotypes. We prove that OHI is NP-hard and can be formulated as an integer quadratic programming (IQP) problem. To solve the IQP problem, we propose an iterative semi-definite programming based approximation algorithm, (called SDPHapInfer). We show that this algorithm finds a solution within a factor of O(logn) of the optimal solution, where n is the number of genotypes. This algorithm has been implemented and tested on a variety of simulated and biological data. In comparison with three other methods: HAPAR, HAPLOTYPER, and PHASE, the experimental results indicate that SDPHapInfer and HAPLOTYPER have similar error rates. In addition, the results generated by PHASE have lower error rates on some data but higher error rates on others. The error rates of HAPAR are higher than the others on biological data. In terms of efficiency, SDPHapInfer, HAPLOTYPER, and PHASE output a solution in a stable and consistent way, and they run much faster than HAPAR when the number of genotypes becomes large.
29539871
On the effectiveness of classification trees for test case construction
Abstract The notion of the classification-hierarchy table and the classification-tree construction algorithm provide a systematic approach to the construction of classification trees from given sets of classifications and their associated classes. Using classification trees, the set of all possible test cases can be constructed from functional specifications. This paper extends their study by introducing a metric to measure the effectiveness of a classification tree with respect to the construction of test cases, and providing ways to improve this effectiveness.