3829528
Dynamically inferring temporal properties
Model checking requires a specification of the target system's desirable properties, some of which are temporal. Formulating a temporal property of the system based on either its abstract model or implementation requires a deep understanding of its behavior and sophisticated knowledge of the chosen formalism. This has been a major impediment to documenting and verifying temporal properties. We propose a dynamic approach to automatically infer a program's temporal properties based on a set of property pattern templates. We describe a preliminary implementation of this approach, and report on our experience using it to discover interesting temporal properties of a small program.
368438
Perracotta: mining temporal API rules from imperfect traces
Dynamic inference techniques have been demonstrated to provide useful support for various software engineering tasks including bug finding, test suite evaluation and improvement, and specification generation. To date, however, dynamic inference has only been used effectively on small programs under controlled conditions. In this paper, we identify reasons why scaling dynamic inference techniques has proven difficult, and introduce solutions that enable a dynamic inference technique to scale to large programs and work effectively with the imperfect traces typically available in industrial scenarios. We describe our approximate inference algorithm, present and evaluate heuristics for winnowing the large number of inferred properties to a manageable set of interesting properties, and report on experiments using inferred properties. We evaluate our techniques on JBoss and the Windows kernel. Our tool is able to infer many of the properties checked by the Static Driver Verifier and leads us to discover a previously unknown bug in Windows.
3836964
Automatically inferring temporal properties for program evolution
It is important that program maintainers understand important properties of the programs they modify and ensure that the changes they make do not alter essential properties in unintended ways. Manually documenting those properties, especially temporal ones that constrain the ordering of events, is difficult and rarely done in practice. We propose an automatic approach to inferring a target system's temporal properties based on analyzing its event traces. The core of our technique is a set of pre-defined property patterns among a few events. These patterns form a partial order in terms of their strictness. Our approach finds the strictest properties satisfied by a set of events based on the traces. We report results from experiments on two sets of programs: student solutions for a class assignment, and several recent versions of OpenSSL Comparing properties inferred from different implementations led us to discover important behavioral differences which revealed flaws in the programs. Differences in automatically inferred temporal properties can provide useful information to programmers evolving complex, often unspecified, programs whose correctness depends on preservation of undocumented temporal properties.
214792426
TIP: a temporal extension to Informix
Commercial relational database systems today provide only limited temporal support. To address the needs of applications requiring rich temporal data and queries, we have built TIP (Temporal Information Processor), a temporal extension to the Informix database system based on its DataBlade technology. Our TIP DataBlade extends Informix with a rich set of datatypes and routines that facilitate temporal modeling and querying. TIP provides both C and Java libraries for client applications to access a TIP-enabled database, and provides end-users with a GUI interface for querying and browsing temporal data.
7182462
On the database/network interface in large-scale publish/subscribe systems
The work performed by a publish/subscribe system can conceptually be divided into subscription processing and notification dissemination. Traditionally, research in the database and networking communities has focused on these aspects in isolation. The interface between the database server and the network is often overlooked by previous research. At one extreme, database servers are directly responsible for notifying individual subscribers; at the other extreme, updates are injected directly into the network, and the network is solely responsible for processing subscriptions and forwarding notifications. These extremes are unsuitable for complex and stateful subscription queries. A primary goal of this paper is to explore the design space between the two extremes, and to devise solutions that incorporate both database-side and network-side considerations in order to reduce the communication and server load and maintain system scalability. Our techniques apply to a broad range of stateful query types, and we present solutions for several of them. Our detailed experiments based on real and synthetic workloads with varying characteristics and link-level network simulation show that by exploiting the query semantics and building an appropriate interface between the database and the network, it is possible to achieve orders-of-magnitude savings in network traffic at low server-side processing cost.
2345378
Segmentation of 3D deformable objects with level set based prior models
We propose a level set based deformable model for the segmentation of multiple objects from 3D medical images using shape prior constraints. As an extension to the level set distribution model of object shape presented in previous papers, this paper evaluates the performance of the level set representation of the object shape by comparing it with the point distribution model(PDM) using the Chi-square test. We define a maximum a posteriori (MAP) estimation model using level set based prior information to realize the segmentation of the multiple objects. To achieve this , only one level set function is employed as the representation of the multiple objects of interest within the image. We then define the probability distribution over the variations of objects contained in a set of training images. We found the algorithm to be computationally efficient, robust to noise, able to handle multidimensional data, and avoids the need for explicit point correspondences during the training phase. Results and validation from various experiments on 2D/3D medical images are demonstrated.
9944435
On the centroids of fuzzy numbers
In a paper by Cheng [A new approach for ranking fuzzy numbers by distance method, Fuzzy Sets and Systems 95 (1998) 307-317], a centroid-based distance method was suggested for ranking fuzzy numbers, both normal and non-normal, where the fuzzy numbers are compared and ranked in terms of their Euclidean distances from their centroid points to the origin. It is found that the centroid formulae provided by the above paper are incorrect and have led to some misapplications. In this paper we present the correct centroid formulae for fuzzy numbers and justify them from the viewpoint of analytical geometry. A numerical example demonstrates that Cheng's formulae can significantly alter the result of the ranking procedure.
5502812
A Continuous Genetic Algorithm for Global Optimization