Gregorio Díaz

University of Castilla-La Mancha · Computer Systems

Renewal energies are key to face the challenges of climate change. The power generation using Wind Turbines (WT) is among the technologies with higher growth during the last year. The Operation and Maintenance (OM) of WT using condition-monitoring (CM) to minimize failures determine the cost of the produced energy and therefore its efficiency. In t...

Tsunamis and earthquakes have a great impact in human lives, infrastructures and economy. Although preventing tsunamis from occurring is impossible, minimizing their negative effects is in our hands. The aim of the Intelligent Transportation System (ITS) proposed in this paper is to provide safer routes for emergency and rescue vehicles. This syste...

Obtaining routes has been a challenge during the recent history of software systems. GPS has helped this technology to be widely used. Some challenges still remain like providing routes in the presence of obstacles. The term obstacle differs depending on the scenario. It is not the same for wheelchair users than for a group of school children. In t...

The control of the pandemic caused by SARS-CoV-2 is a challenge for governments all around the globe. To manage this situation, countries have adopted a bundle of measures, including restrictions to population mobility. As a consequence, drivers face with the problem of obtaining fast routes to reach their destinations. In this context, some recent...

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-...

Business processes (BPs) are subject to frequent and unpredictable changes caused by new laws or modifications in the business environment, including user requirements. Many running instances are migrated to new BPs during a BP change, even when these instances satisfy the new requirements. We propose a migration strategy to ignore the migration of...

Models@runtime (models at runtime) are based on computation reflection. Runtime models can be regarded as a reflexive layer causally connected with the underlying system. Hence, every change in the runtime model involves a change in the reflected system, and vice versa. To the best of our knowledge, there are no runtime models for Python applicatio...

We propose a formal approach based on Bigraphical Reactive Systems (BRSs) and model checking techniques for modeling and verifying the interaction behaviours of SLA-based cloud computing systems. In the first phase of this approach, we address the modeling of the static structure and the dynamic behavior of cloud systems using BRSs. We show how big...

Air pollution generated by road traffic in large cities is a great concern in today’s society since pollution has an important impact on human health, even causing premature deaths. To address the problem, this paper presents an Intelligent Transportation System model based on Complex Event Processing technology and Colored Petri Nets (CPNs). It ta...

Complex event processing (CEP) is a computational intelligence technology capable of analyzing big data streams for event pattern recognition in real time. In particular, this technology is vastly useful for analyzing multicriteria conditions in a pattern, which will trigger alerts (complex events) upon their fulfillment. However, one of the main c...

Road traffic has become a main source of air pollution in urban areas. For this reason, governments are applying traffic regulations trying to fulfill the recommendations of Air Quality (AQ) standards in order to reduce the pollution level. In this paper, we present a novel proposal to improve AQ in cities by combining fuzzy logic and Complex Event...

Air pollution is currently a great concern especially in large cities. To reduce pollution levels, governments are imposing traffic restrictions. However, the decision about which grade of traffic restriction must be applied in a particular city zone is a cumbersome task. This decision depends on the pollution scenario occurred at a time period. To...

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 ev...

Computational thinking may be defined as the systematic development of critical thinking and problem solving skills supported by computational concepts. The literature shows the numerous benefits of implementing the ideas behind computational thinking in the teaching/learning process at very early ages. This means in practice that children and teen...

Pollution due to road traffic in big cities is an important problem in our society, with consequences for human health. In this paper we deal with this problem, proposing an Intelligent Transportation System (ITS) model based on Complex Event Processes (CEP) technologies and Petri nets that takes into account the levels of environmental pollution a...

We present two data-aware algorithms to automatically derive web service compositions from global specifications. We show that a natural projection oriented derivation does not work in general, since some issues arise when projecting the set of implementations from the global specification, and we show how our approach deals with them. We use the c...

Complex Event Processing (CEP) is a technology that allows us to process and correlate large volumes of data by using event patterns, aiming at promptly detecting specific situations that could require special treatment. The event types and event patterns for a particular application domain are implemented by using an Event Processing Language (EPL...

Relationships between entities in today’s increasingly interconnected context have grown in complexity and evolved from simple communication processes to more complicated distributed systems. Electronics contracts (e-contracts) are of general purpose and aimed to specify relationships in a wide variety of scenario, including web and cloud services,...

In this paper we present a Timed Automata model for the Publish/Subscribe paradigm in the context of Web Service Compositions with distributed resources, on the basis of an algebraic language inspired by the WSRF standard constructions. This framework allows a set of participants in a Web Service composition to interact with one another and also to...

In this paper a Prioritized-Timed Colored Petri Net model for the Publish/Subscribe paradigm in the context of Web services distributed resources is considered. We present a generic CPN model for publishing and managing WS-resources, which includes operations for clients to subscribe to these resources, with the intention of being notified when the...

In this paper we consider a Timed Automata model for the Publish/Subscribe paradigm, where special attention is given to its temporal aspects. Despite this special interest, we present a generic model for publishing and managing WS-resourses in the context of Web services with distributed resources. The model includes operations for clients to disc...

Composite Web services technologies are widely used due to their ability to provide interoperability among services from different companies. Web services are usually stateless, which means that no state is stored from the clients viewpoint. However, some new applications and services require to capture the state of some resources after each comput...

C-O diagrams have been introduced as a means to have a more visual representation of normative texts and electronic contracts, where it is possible to represent the obligations, permissions and prohibitions of the different signatories, as well as the penalties resulting from non-fulfillment of their obligations and prohibitions. In such diagrams w...

Design and implementation via contractual specifications helps designers and programmers understand and analyze when the requirements have been elicited according to the client’ desires. In general, software is released when some tests have been successfully passed. However, these tests only cover a finite set of possible executions. But in systems...

We present DIEGO 2.0, a new version of our tool DIEGO. Given a WS-CDL choreography, it automatically ex-tracts a set of WS-BPEL web services such that, if these services interact with each other, they necessarily produce the behavior defined in the choreography even if the natural projection does not work. This is achieved by introducing some contr...

C-O Diagrams have been introduced as a means to have a visual representation of normative texts and electronic contracts, where it is possible to represent the obligations, permissions and prohibitions of the different signatories, as well as what are the penalties in case of not fulfillment of their obligations and prohibitions. In such diagrams w...

Web service compositions are gaining attention to develop complex web systems by combination of existing services. Thus, there are many works that leverage the advantages of this approach. However, there are only few works that use web service compositions to manage distributed resources. In this paper, we then present a formal model that combines...

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 (...

We present a formal model to represent orchestrations and choreographies and we define several conformance semantic relations allowing to detect whether a set of orchestration models, representing some web services, leads to the overall communications described in a choreography. Given this formal model, we develop automatic methods to derive a set...

In the field of service-oriented computing, an e-contract is used to regulate the acceptable behaviours of the services taking part in a composition. C-O Diagrams are a visual model for the specification of deontic e-contracts, including reparations, conditional clauses and real-time restrictions. In this work we define a set of satisfaction rules...

C-O Diagrams have been introduced as a means to have a more visual representation of electronic contracts, where it is possible to represent the obligations, permissions and prohibitions of the different signatories, as well as what are the penalties in case of not fulfillment of their obligations and prohibitions. In such diagrams we are also able...

Web service compositions are gaining increasingly attention for the development of complex web systems by combination of existing ones. In this paper, we present a formal framework that integrates a well-known business process language (BPEL) with a recent technology for describing distributed resources throughout the Internet (WSRF). We define an...

We present a tool to automatically derive choreography-conforming web services systems. The user provides a specification that describes peer-to-peer collaborations of the observable behavior of parties from a global viewpoint, in our case WS-CDL documents, and the tool automatically extracts the particular behavior of each participant, more concre...

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...

In a web service composition, an electronic contract (e-contract) regulates how the services participating in the composition should behave, including the restrictions that these services must fulfill, such as real-time constraints. In this work we present a visual model that allows us to specify e-contracts in a user friendly way, including condit...

As the consensus of using web services as an alternative to traditional deployment models has been growing during the last years, also new techniques to face the new arisen problems have been developed. In this work, we present the design of a conference management system by using a composition of web services as deployment model. We bring our atte...

The main objective of this paper is to present an approach to accomplish verification in the early design phases of a system, which allows us to make the system verification easier, specifically for those systems with timing restrictions. For this purpose we use RT-UML sequence diagrams in the design phase and we translate these diagrams into timed...

In this paper we introduce a tool called the Web Service Translation tool (WST), which we are developing to implement a methodology for the design, validation and verification of Web Services with timed restrictions. This methodology works by making several translations, from phase to phase in the software development life cycle, where the system i...

This paper presents an enhanced derivation procedure to obtain a system of services, from a given choreography. In addition to the basic framework, we introduce several situations where nondeterminism appears and it is resolved by using a dynamic prioritized system. The priority policy is based on several parameters such as the request dispatching,...

As the consensus of using web services as an alternative to traditional deployment models has been growing during the last years, also new techniques to face the new arisen problems have been developed. In this work, we present the design of a conference management system by using a composition of web services as deployment model. We bring our atte...

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 t...

In this paper we present a formal model to represent orchestrations and choreographies, and we provide some semantic relations to detect their conformance, i.e., whether a set of orchestrations representing some web services leads to the overall communications described in a choreography.

In this work we explain how to perform the design and verification of a Web services composition with time restrictions using the Web services translation tool, WST for short. We pay special attention to Web services systems with timing restrictions. As illustration, we use a case study called ldquoform generator servicerdquo, a system that allows...

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 inte...

In this paper, a formal analysis of security protocols in the field of wireless sensor networks is presented. Three complementary protocols, TinySec, LEAP and TinyPK, are modelled using the high-level formal language HLPSL, and verified using the model checking tool AVISPA, where two main security properties are checked: authenticity and confidenti...

We present a formal method to derive a set of web ser- vices from a given choreography, in such a way that the sys- tem consisting of these services necessarily conforms to th e choreography. A formal model to represent orchestrations and choreographies is given, and we define several confor- mance semantic relations allowing to detect whether a se...

In this work we extend SCA models with timing restrictions to capture the behavior of systems where time determines the correctness of the implementation. Furthermore, we establish a translation from this extended model in the timed automata formal model. In this case, we have considered the timed automata formalism supported by the UPPAAL tool, du...

Choreography languages allow us to describe Web Ser- vices compositions from a global viewpoint in Service Ori- ented Architectures (SOA). However, none of the existing languages has achieved the status of de facto standard for that purpose until now. In this paper we compare three ex- isting proposals to specify Web Services choreographies: WSCI,...

Transport Layer Security (TLS) is a security protocol widely used in e-commerce in recent years. This protocol has been extended in order to deal with clients connecting from mobile devices (PDAs, cellular phones) through a wireless network. The main goal of this paper is to prove, using model checking techniques, that TLS Handshake and its wireles...

Process Algebra Description Language, PADL in short, is a description language for describing structural components specified as individual process working in parallel with communication capabilities. This description is close to what we consider a web service except for the communication process. The PADL language is consider for synchronous commu...

In previous work we have presented the generation of WS-CDL and WS-BPEL documents. In this paper we show the unification of both generations. The aim is to generate correct WS-BPEL skeleton documents from WS-CDL documents by using the Timed Automata as an intermediary model in order to check the correctness of the generated Web Services with Model...

In this paper we have used the Markovian process algebra ROSA to both specify and analyze the memorizing process. ROSA , reasoning on stochastic algebras, is an algebraic language for the description of probabilistic and non-deterministic processes, which allows us to evaluate performance indexes and to check some temporal requirements.

In this paper we show how we can use a classical UML diagram, the sequence diagram, for the description of business process behavior based on Web services with time constraints. More specifically, we see how these diagrams can capture the main elements of the Web services business process execution language (WS-BPEL), and then, how we can translate...

Web services secure conversation extends Web services trust to provide mechanisms for establishing security contexts. A security context is an abstract concept that refers an authenticated state where the participants have derived secure session keys for multiples request/response exchanges. In this paper we model this protocol with the HLPSL langu...

In this paper we present the testing of time goal requirements by using model checking as an engine for test generation. The goal model that we use to capture the time requirements is an extension of KAOS. This goal model specifies the properties that the system must satisfy and how they are tested by using the model checker engine, UPPAAL. As an i...

Timed Automata is a well known formalism for the description of Real-Time System. In this paper we show that it is useful for modelling and analyzing Web Services with time constraints. For our purposes it is enough with the choreography level of the Web Services Architecture, so Web Services descriptions written in WSCDL (a XML-based description l...

In this paper we show how we can use the UML profile for modeling real time systems, which allows us to describe Web services choreographies with time constraints. More specifically, we see how by using the diagrams of this profile, we can capture the main elements of a real-time Web Services Choreography Description Language specification (WS-CDL)...

This work presents a new approach to the analysis and veri- flcation of the time requirements of Web Services compositions via goal- driven models,and model checking techniques. The goal-driven model used is an extension of the goal model KAOS and the model checker engine is the UPPAAL tool. The goal model,specifles the properties that the system m...

In this paper we show how we can use formal methods for describing and analyzing the behavior of Web Services, and more specifically those including time restrictions. Then, our starting point are Web Services descriptions written in WSCI – WSCDL (XML-based description languages). These descriptions are then translated into timed automata, and then...

In previous work we have presented the generation of WS-CDL and WS-BPEL documents. In this paper we show the unification of both generations. The aim is to generate correct WS-BPEL skeleton documents from WS-CDL documents by using the Timed Automata as an intermediary model in order to check the correctness of the generated Web Services with Model...

In this work we describe an approach to deal with systems having at the same time probabilistic and real-time behav-iors. The main goal in the paper is to show the automatic translation from a real time model based on UPPAAL tool, which makes automatic verification of Real Time Systems, to the RAPTURE tool, which makes verification of proba-bilisti...

Software engineers work gladly with process algebras, as they are very similar to programming languages. However, graphical models are better in order to understand how a system behaves, and even these graphical models allow us to analyze some properties of the systems. Then, in this paper we present two formalisms for the specification of concurre...

Web Services technologies have introduced a new challenge for security protocols. Traditional security protocols cannot handle intermediaries and the flexibility of Web Services bindings. Thus, several proposals for introducing security in Web Services have been presented. One of these is Web Services Security. In this paper we illustrate how this...

In this paper we show how,we can translate Web Services described by WS-CDL into a timed automata orchestration, and more specifically we are interested in Web services with time restrictions. Our starting point are Web Services descriptions written in WSBPEL - WSCDL (XML-based description languages). These descriptions are then automatically trans...

E-commerce is based on transactions between client and server agents. These transactions require a protocol that provides privacy and reliability between these two agents. A widely used protocol on e-commerce is Transport Layer Security (TLS). In this paper we present a way to use Formal Methods to ensure the e-commerce properties of this protocol....

The performance of many parallel applications takes great benefits from the improvements made on multicomputer interconnection networks. The routers on which these networks are based should be carefully designed in order to offer good performance, while keeping their implementations as simple and cost-effective as possible. In this paper, we presen...

The performance of many parallel applications takes great benefits from the improvements made on multicomputer interconnection networks. The routers on which these networks are based should be carefully designed in order to offer good performance, while keeping their implementations as simple and cost-effective as possible. In this paper we present...

We use a timed extension of Petri nets, the so called Timed-Arc Petri Nets, for the specification and analysis of the MPEG–2 Video Encoder. We have computed bounds for the necessary time to encode each type of frame, also we present an improvement on the encoding process which takes advantage of the potential parallelism degree of the MPEG–2 video...

In this paper, a formal analysis of a security protocol in the field of wireless sensor networks is presented. MiniSec is a secure network layer protocol for wireless sensor networks. It provides confiden-tiality, data authentication, replay protection and weak message fresh-ness with low energy consumption. It can work in two modes –MiniSec-U and...

Resumen En este articulo presentamos un trabajo que actualmente se encuentra en curso y en el que se realiza una modelizacion y analisis de un sistema de con- trol de riegos basado en servicios Web. Para conseguir nuestro objetivo el sistema es modelado mediante automatas temporizados que seran verificados mediante la herramienta UPPAAL que nos per...

Throughout the history of computing, engineers h