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A way to reduce carbon emissions in cities is through movement by bicycle or on foot. However, it sometimes means to pass through high-pollution zones and consequently breath low quality air. We then propose a green Intelligent Transportation System (ITS) for zero-emission mobility users, providing users with low-pollution routes to avoid the high-pollution zones. This proposal uses ITS to promote the use of alternative transportation to classical motor vehicles to reduce carbon emissions. This is based on Complex Event Processing (CEP) technology to gather and process real-time data, a Decision Support System designed as a Fuzzy Inference System (FIS) to make decisions about recommended transit zones, taking also into account the user experience level and specific weather data, and Colored Petri Nets (CPN) as a tool to compute the routes. This is therefore an all-in-one solution to provide green routes, with the benefits of each one of the technologies used.

Complex Event Processing (CEP) is an event-based technology that allows us to process and correlate large data streams in order to promptly detect meaningful events or situations and respond to them appropriately. CEP implementations rely on the so-called Event Processing Languages (EPLs), which are used to implement the specific event types and event patterns to be detected for a particular application domain. To spare domain experts this implementation, the MEdit4CEP approach provides them with a graphical modeling editor for CEP domain, event pattern and action definition. From these graphical models, the editor automatically generates a corresponding Esper EPL code. Nevertheless, the generated code is syntactically but not semantically validated. To address this problem, MEdit4CEP is extended in this paper by Prioritized Colored Petri Net (PCPN) formalism, resulting in the MEdit4CEP-CPN approach. This approach provides both a novel PCPN domain-specific modeling language and a graphical editor. By using model transformations, event pattern models can be automatically transformed into PCPN models, and then into the corresponding PCPN code executable by CPN Tools. In addition, by using PCPNs we can compare the expected output with the actual output and can even conduct a quantitative analysis of the scenarios of interest. To illustrate our approach, we have conducted an air quality level detection case study and we show how this novel approach facilitates the modeling, simulation, analysis and semantic validation of complex event-based systems.

We propose discrete time stochastic Petri box calculus extended with immediate multiactions, called dt-siPBC. The step operational semantics is constructed via labeled probabilistic transition systems. The denotational semantics is defined via labeled discrete time stochastic Petri nets with immediate transitions (LDTSIPNs). A consistency of both semantics is demonstrated. In order to evaluate performance, the corresponding semi-Markov chains are analyzed. In a case study, performance of the shared memory system is evaluated.

Web services managing distributed resources is a technology that allows the user to have an easier and cheaper mechanism to access and manage distributed resources. Then, the formal modeling of web services with distributed resources becomes very important in order to understand accurately their behavior. In this paper, we present a framework to model these systems by using a widely adopted standard (UML 2.0), enriched with the resource management capabilities, on the basis on WSRF.

A Web Service is a self-describing, self-contained modular application that can be published, located, and invoked over a network, such as the Internet. Web Service composition provides a way to obtain value-added services by combining different existing facilities, which are then able to support the integration of commercial applications. WS-CDL (Web Services Choreography Description Language) is a W3C candidate recommendation for the description of peer-to-peer collaborations by participants in a Web Services composition. This paper focuses on several important aspects of WS-CDL, namely, data variables, timed restrictions, as well as the priorization of collaborations. In WS-CDL there are no priorities, thus, one of our first goals is to provide a WS-CDL definition of prioritized collaborations. We also define a semantics of WS-CDL (with priorities) by means of prioritized-timed colored Petri nets.

We present an approach for the validation and verification of Web services choreographies, and more specifically, for those composite Web services systems with timing restrictions. We use a W3C proposal for the description of composite Web services, WS-CDL (Web Services Choreography Description Language), and we define an operational semantics for a relevant subset of it. We then define a translation of the considered subset of WS-CDL into a network of timed automata, proving that this translation is correct. Finally, we use the UPPAAL tool for the validation and verification of the described system, by using the generated timed automata.

Web Services composition provides a way to obtain value-added services by combining several Web Services. WS-CDL (Web Services Choreography Description Language) is a W3C candidate recommendation for the description of peer-to-peer collaborations for the participants in a Web Services composition. However, the semantics of WS-CDL is provided in a textual way, and hence a complete rigorous semantics is lacking. In this paper we focus our attention on the WS-CDL elements related to concurrency, as well as on the collaborations that have timing restrictions associated. We then provide an operational semantics for a relevant subset of WS-CDL, paying special attention to timed collaborations. This operational semantics is based on barred terms, which allow us to capture the current state of the choreography throughout its execution.

A Web Service is a self-describing, self-contained modular application that can be published, located, and invoked over a network, e.g. the Internet. Web Services composition provides a way to obtain value-added services by combining several Web Services. The composition of Web Services is, therefore, suitable to support enterprise application integration. WS-CDL (Web Services Choreography Description Language) is a W3C candidate recommendation for the description of peer-to-peer collaborations for the participants in a Web Services composition. In this paper we focus our attention on the development of a methodology for the design and validation of composite Web Services using WS-CDL as the language for describing Web Services interactions and Petri nets as a formalism that allows us to simulate and validate the described systems. We specifically intend, then, to capture timed and prioritized collaborations in composite Web Services, so the model of Petri nets that we use is a prioritized version of Time Petri nets.

TPALp is an algebraic language for the description of concurrent systems with capabilities to express timed and probabilistic behaviours, as well as urgent interactions. In this paper we present the main features of the language, its operational semantics, and a translation of TPALp terms into a particular class of timed-probabilistic Petri nets. The language includes a probabilistic choice operator, a timed prefix operator, and an urgent prefix operator, as well as some other operators that we may find in classical process algebras. An important feature of the language is that urgency is considered at any instant by executing as many urgent actions as possible, with the goal of complying in a great extent with the urgent actions indicated in the user specifications.

The authors present both the specification and a performance analysis of the MPEG2 algorithm for video encoding, by using the Stochastic Process Algebra ROSA. This process algebra is a very general framework for describing and analyzing more complex Real Time Systems than the one presented. Some interesting results about the temporal behaviour of the algorithm and an immediate estimation of benefits when having a twin-processors platform have been obtained.

This paper introduces a general framework of probabilistic and nondeterministic recursive processes that considers three complementary views of the semantics of concurrent processes: behavioural (testing semantics), denotational and axiomatic. The process algebra we present, PNAL, is a full probabilistic extension of EPL ( Algebraic Theory of Processes , M. Hennessy) that maintains nondeterminism. This language allows us to consider both qualitative and quantitative aspects of concurrent systems, which are important in order to obtain more realistic models.

We present an algebraic language for the specification of probabilistic and nondeterministic processes, PNAL, which is a probabilistic extension of EPL that maintains nondeterminism.