Using a SAT solver to generate checking sequences

Methods for software testing based on Finite State Machines (FSMs) have been researched since the early 60’s. Many of these methods are about generating a checking sequence from a given FSM which is an input sequence that determines whether an implementation of the FSM is faulty or correct. In this paper, we consider one of these methods, which constructs a checking sequence by reducing the problem of generating a checking sequence to finding a Chinese rural postman tour on a graph induced by the FSM; we re-formulate the constraints used in this method as a set of Boolean formulas; and use a SAT solver to generate a checking sequence of minimal length

Checking sequence construction using adaptive and preset distinguishing sequences

Methods for testing from finite state machine-based specifications often require the existence of a preset distinguishing sequence for constructing checking sequences. It has been shown that an adaptive distinguishing sequence is sufficient for these methods. This result is significant because adaptive distinguishing sequences are strictly more common and up to exponentially shorter than preset ones. However, there has been no study on the actual effect of using adaptive distinguishing sequences on the length of checking sequences. This paper describes experiments that show that checking sequences constructed using adaptive distinguishing sequences are almost consistently shorter than those based on preset distinguishing sequences. This is investigated for three different checking sequence generation methods and the results obtained from an extensive experimental study are given

Minimizing coordination channels in distributed testing

Testing may be used to show that a system under test conforms to its specication. In the case of a distributed system, one may have to use a distributed test architecture, involving p testers in order to test the system under test. These p testers may under some circumstances have to coordinate their actions with each other using external coordination channels. This may require the use of up to p2 p unidirectional coordination channels in the test architecture, which can be an extensive and expensive setup. In this paper, we propose a method to generate checking sequences while minimizing the number of required coordination channels, by adapting existing methods that generate checking sequences to be applied in a centralized test architecture. We consider the case of unidirectional and bidirectional coordination channels, and the case of transitive coordination

A Brief History of Web Crawlers

Web crawlers visit internet applications, collect data, and learn about new web pages from visited pages. Web crawlers have a long and interesting history. Early web crawlers collected statistics about the web. In addition to collecting statistics about the web and indexing the applications for search engines, modern crawlers can be used to perform accessibility and vulnerability checks on the application. Quick expansion of the web, and the complexity added to web applications have made the process of crawling a very challenging one. Throughout the history of web crawling many researchers and industrial groups addressed different issues and challenges that web crawlers face. Different solutions have been proposed to reduce the time and cost of crawling. Performing an exhaustive crawl is a challenging question. Additionally capturing the model of a modern web application and extracting data from it automatically is another open question. What follows is a brief history of different technique and algorithms used from the early days of crawling up to the recent days. We introduce criteria to evaluate the relative performance of web crawlers. Based on these criteria we plot the evolution of web crawlers and compare their performanc

Recovering representations of systems with repetitive subfunctions from observations

This paper proposes an algorithm for the construction of an MSC graph from a given set of actual observations of an existing concurrent system which has repetitive subfunctions. When a design representing the current functionality of the existing system is desired, such a graph can be checked for safe realizability and be used as input to existing synthesis techniques to construct the design for the system functionality

Degree Navigator^TM: The Journey of a Visualization Software

In this paper, we follow the evolution of a tool that has its roots in academic research on visualization and graph drawing. From its ancestor Order Explorer (1994) and initial version of 1995, to its latest version of 2003, we analyze the significant steps of a software that has gone from being a relatively simple, very specialized research tool to being a successful, widely deployed, complex commercial software used for academic degree audits. As the tool has expanded over the years, the initial scope has been completely outgrown and finding back the original idea in the current version is not completely obvious. Never the less, Degree Navigator^TM is a wonderful example of a research project that has gone a long way

Improved Usage Model for Web Application Reliability Testing

International audienceTesting the reliability of an application usually requires a good usage model that accurately captures the likely sequences of inputs that the application will receive from the environment. The models being used in the literature are mostly based on Markov chains. They are used to generate test cases that are statistically close to what the application is expected to receive when in production. In this paper, we study the specific case of web applications. We present a model that is created directly from the log file of the application. This model is also based on Markov chains and has two components: one component, based on a modified tree, captures the most frequent behavior, while the other component is another Markov chain that captures infrequent behaviors. The result is a statistically correct model that exhibits clearly what most users do on the site. We present an experimental study on the log of a real web site and discuss strength and weakness of the model for reliability testing

AutoGAN: An Automated Human-Out-of-the-Loop Approach for Training Generative Adversarial Networks

Generative Adversarial Networks (GANs) have been used for many applications with overwhelming success. The training process of these models is complex, involving a zero-sum game between two neural networks trained in an adversarial manner. Thus, to use GANs, researchers and developers need to answer the question: “Is the GAN sufficiently trained?”. However, understanding when a GAN is well trained for a given problem is a challenging and laborious task that usually requires monitoring the training process and human intervention for assessing the quality of the GAN generated outcomes. Currently, there is no automatic mechanism for determining the required number of epochs that correspond to a well-trained GAN, allowing the training process to be safely stopped. In this paper, we propose AutoGAN, an algorithm that allows one to answer this question in a fully automatic manner with minimal human intervention, being applicable to different data modalities including imagery and tabular data. Through an extensive set of experiments, we show the clear advantage of our solution when compared against alternative methods, for a task where the GAN outputs are used as an oversampling method. Moreover, we show that AutoGAN not only determines a good stopping point for training the GAN, but it also allows one to run fewer training epochs to achieve a similar or better performance with the GAN outputs