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The research tries to give response to a question that all Venezuelan people constantly ask: are economic resources of the nation well administered? Based on this question, we realize a study on the efficiency and the productivity of the State in the use of the gross domestic product (GDP) for generating social welfare, to increase the economic levels of the country and to cancel the foreign debt...
In this paper we apply a passive testing methodology to the analysis of a non-trivial system. In our framework, so-called invariants provide us with a formal representation of the requirements of the system. In order to precisely express new properties in multi-node environments, in this paper we introduce a new kind of invariants. We apply the resulting framework to perform a complete study of a...
In this paper we define simulation relations for distributed systems. Taking as starting point our previous work on the distributed testing architecture, we introduce novel simulation relations that can be used to define, given a specification, what a good implementation is. We approach the problem from two different perspectives. First, we consider that different ports of the system cannot share...
In this paper we present a formal passive testing framework and use it to analyze time aspects in the stream control transmission protocol (SCTP). This protocol presents different phases where time aspects are critical. In order to represent temporal requirements we use so-called timed invariants since they allow us to easily verify that the traces collected from the observation of the protocol fulfill...
Testing is one of the most widely used techniques to increase the quality and reliability of complex software systems. In this paper we extend our previous work on passive testing with invariants to incorporate (probabilistic) knowledge obtained from users of the system under test. In order to apply our technique, we need to obtain a set of invariants compiling the relevant properties of the system...
In this paper we extend our previous work on passive testing of timed systems to establish a formal criterion to determine correctness of an implementation under test. In our framework, an invariant expresses the fact that if the implementation under test performs a given sequence of actions, then it must exhibit a behavior in a lapse of time reflected in the invariant. In a previous paper we gave...
In this paper we introduce a formal methodology to perform passive testing, based on invariants, for systems where the passing of time is represented in probabilistic terms by means of probability distributions functions. In our approach, invariants express the fact that each time the implementation under test performs a given sequence of actions, then it must exhibit a behavior according to the probability...
In this paper we introduce a formal framework to specifyagent-based systems where each agent is specialized ina single task that will be fulfilled by making calls to other simpler agents. In other words, we are interested in systems that can perform a task by subdividing it in easier tasks and by using the knowledge about each agent already introduced in the system. The idea is to prefabricate a basic...
The main goal of this paper is to provide an algorithm to derive finite test suites, from timed specifications, according to a given coverage criterium. First, we introduce a timed extension of the finite state machines model. We consider that (output) actions take time to be performed. In addition to present our formalism, we develop a testing theory. Thus, we introduce a notion of timed test and...
One of the main problems to test timed systems is that the tester has to decide when to apply the next input to the system under test. Even though the tester could determine good sequences of inputs to find a big variety of errors, the quality of the test suite usually depends on the time when the different parts of the sequences are applied. In this paper we give a formal methodology to provide good...
In November 2002, the sinking of the Prestige oil tanker off the Galician coast (N.W. Spain) caused the largest ecological catastrophe in the history of Spain, affecting the coast called the ‘Costa da Morte’ (Galicia, N.W. Spain).This work is focused on the study of the oil contamination of the intertidal area of two beaches located on this stretch of coast. The study of twenty cores extracted from...
Abstract. We have performed detailed resistivity measurements as a function of temperature in the range from 12 to 300K on oxygen loaded C60 films. We observe that two ordering phase transitions (i.e., T0=260 K and Tg=90 K) are present in (T), which, in addition, strongly depends on the oxygen content. We find a decrease of both ordering temperatures with increasing oxygen concentrations. The mechanisms...
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