Julio Medina | Universidad de Cantabria (original) (raw)

Papers by Julio Medina

2015 Forum on Specification and Design Languages (FDL), 2015

The design of distributed embedded systems is a challenging task that requires raising the level ... more The design of distributed embedded systems is a challenging task that requires raising the level of abstraction to handle the different involved concerns. In particular, standard modeling languages and precise semantics specification are necessary to address the networking-related aspects at a high level of abstraction. The Unified Modeling Language (UML) and its MARTE profile are valid formalisms to model real-time embedded systems but they lack precise modeling elements when addressing applications and platforms forming distributed embedded systems. In this work, we formalize a coherent set of modeling elements for the design and deployment of distributed embedded systems. A novel UML profile for networking is proposed as a semantic and syntactic extension to the UML Profile for MARTE: The Network Profile.

2016 Euromicro Conference on Digital System Design (DSD), 2016

This document may be copied freely for use in the public domain. Sections of it may be copied pro... more This document may be copied freely for use in the public domain. Sections of it may be copied provided that acknowledgement is given of this original work. No responsibility is assumed by CONTREX or its members for any application or design, nor for any infringements of patents or rights of others which may result from the use of this document.

a series of events focusing on designing robust components and systems with testability for vario... more a series of events focusing on designing robust components and systems with testability for various features of behavior and interconnection. Complex distributed systems with heterogeneous interconnections operating at different speeds and based on various nano-and micro-technologies raise serious problems of testing, diagnosing, and debugging. Despite current solutions, virtualization and abstraction for large scale systems provide less visibility for vulnerability discovery and resolution, and make testing tedious, sometimes unsuccessful, if not properly thought from the design phase. The conference on advances in system testing and validation considered the concepts, methodologies, and solutions dealing with designing robust and available systems. Its target covered aspects related to debugging and defects, vulnerability discovery, diagnosis, and testing. The conference provided a forum where researchers were able to present recent research results and new research problems and d...

Due to the rapid increase in the functionality requirements of automotive control networks, mixed... more Due to the rapid increase in the functionality requirements of automotive control networks, mixed CAN (Controller Area Network) and Ethernet networks have recently gained considerable attention. This paper presents a simulation environment for CAN–Ethernet networks based on the opensource network simulator OMNeT++, part of the INET framework. We develop simulation models of CAN and a CAN– Ethernet Gateway (GW). To validate the CAN model, we measure the end-to-end latency of CAN messages and compare its performance with an existing CAN network simulator. We apply the proposed simulation environment to an automotive CAN– Ethernet system, and confirm that it is an effective aid in the design and evaluation of such networks.

ACM SIGBED Review, 2011

Consider the design of hard real-time distributed systems using a model-based and composable appr... more Consider the design of hard real-time distributed systems using a model-based and composable approach, in which their specification is made using a high level modelling language like UML. This demo abstract, presents a tool-aided methodology to enable the composition and transformation of such design intended models into also composable schedulability analysis models usable in the verification of the timing properties of the fully composed and loaded systems. In order to annotate the required non-functional properties and state other real-time enabling features, the UML profile for Modeling and Analysis of Real-Time and Embedded systems (MARTE), a recent modeling standard of the OMG, has been used. The methodology comprises several methodological guidelines, specific model transformations, and finally the generation as an output of the concrete schedulability analysis models used by the MAST set of tools, whose results are back annotated into the high level design UML models. 1. This work has been funded by the European Union under contracts, FP7/NoE/214373 (ArtistDesign), and FP7/CSA/224330 (ADAMS); and by the Spanish Government under grant TSI-020400-2009-108 (ITEA2-EVOLVE). This work reflects only the author's views; the EU is not liable for any use that may be made of the information contained herein.

Proceedings of IX Forum on Specification …, 2006

The specification of real-time components must include information about their timing behaviour i... more The specification of real-time components must include information about their timing behaviour in order to evaluate the schedulability of the applications that use them. This work presents a set of concepts that may be considered in the standardization effort of the ...

OMG document formal/03- …, 2003

In this paper we address some aspects of the &amp;quot;UML Profile for Schedulability, Pe... more In this paper we address some aspects of the &amp;quot;UML Profile for Schedulability, Performance and Time&amp;quot; (SPT), that have been found to be improvable. In particular, we describe problems and possible solutions related to the usage of the profile in the representation of schedulability analysis models for real-time distributed systems. The issues appear mainly from a comparison between the SPT and the concepts used in MAST (Modeling and Analysis Suite for Real-Time Applications).

Handbook of Hardware/Software Codesign, 2017

Model-based design has shown to be a powerful approach for embedded software systems. The Unified... more Model-based design has shown to be a powerful approach for embedded software systems. The Unified Modeling Language (UML) provides a standard, graphically based formalism for capturing system models. The standard Modeling and Analysis of Real-Time Embedded Systems (MARTE) profile provides syntactical and semantical extensions required for the modeling and HW/SW codesign of real-time and embedded systems. However, the UML/MARTE standard is not sufficient. In addition, a modeling methodology stating how to build a model capable to support the analysis and HW/SW codesign activities of complex embedded systems is required. This chapter presents a UML/MARTE modeling methodology capable to address such analysis and design activities. A distinguishing aspect of the modeling methodology is that it supports a singlesource design approach.

2015 Conference on Design of Circuits and Integrated Systems (DCIS), 2015

Mixed-critical systems combine highly-critical tasks with non-critical activities. Among them, th... more Mixed-critical systems combine highly-critical tasks with non-critical activities. Among them, there is a trend of sharing the available HW resources for all these activities, as a way of optimizing costs and power consumption. However, the design of such complex systems is a challenge, due to the different requirements and goals of critical and non-critical tasks, and the side effects resulting from their integration. As a consequence, the design of mixed critical systems requires the integration of different design flows and tools, and consideration of the whole system during the development of each specific component. To handle this challenge, this paper presents a single-source proposal where UML models are used as a common input that drives a flow of different design tools in a mixed-critical context. The flow covers performance estimation, static schedulability analysis and code synthesis to guarantee the critical tasks' constraints and to evaluate the remaining times available for the execution of non-real time tasks.

Real-Time and Computers Group. University of Cantabria. SPAIN http://www.ctr.unican.es !UML-MAST ... more Real-Time and Computers Group. University of Cantabria. SPAIN http://www.ctr.unican.es !UML-MAST models and tools can be used in combination with most of the available UML CASE tools. At present, we have implemented for Rational Rose.

Resumen: El modelo de tiempo real es la base del proceso de especificación, análisis, diseño y va... more Resumen: El modelo de tiempo real es la base del proceso de especificación, análisis, diseño y validación de cualquier aplicación de tiempo real. Tradicional- mente este modelo se ha formulado siguiendo el modelo reactivo con el que la aplicación ha sido concebida. Sin embargo, en sistemas complejos, en los que las aplicaciones de tiempo real se diseñan utilizando una metodología

IEEE Symposium on Emerging Technologies and Factory Automation, ETFA, 2007

In this paper we overview the integration of a framework that generically manages the system reso... more In this paper we overview the integration of a framework that generically manages the system resources in the form of contracts, namely the FRESCOR framework, with a flexible network resource. We describe how a network resource, namely FTT-SE, supports the FRESCOR framework services and, likewise, how the network services are made available to the application through the contracting framework. In a designer perspective, we also describe how a typical distributed application can be easily deployed using such a framework.

32nd EUROMICRO Conference on Software Engineering and Advanced Applications (EUROMICRO'06)

This paper presents a modular modelling methodology to formulate the timing behaviour of real-tim... more This paper presents a modular modelling methodology to formulate the timing behaviour of real-time distributed component-based applications. It allows to build real-time models of the platform resources and software components, which are reusable and independent of the applications that use them. The proposed methodology satisfies the completeness, opacity and composability properties, required to ensure that the complete real-time model of an application, able to predict its temporal behaviour by schedulability analysis or simulation, may be assembled by composition of the real-time models of its constituent parts. These real-time models present a dual descriptor/instance based nature. A class of component, independent of any application, is modelled as a parameterized class-type descriptor, which describes its inherent temporal behaviour and includes references to the real-time models of other hardware/software modules that it requires. An instance of the component in a concrete application context is modelled by an instance-type model, which is generated by assigning concrete values to the parameters and unsolved references of its corresponding descriptor. Instances are formed and combined by automatic tools to build complete analysis models for each specific real-time situation.

Lecture Notes in Computer Science, 2002

Proceedings of the 11th international workshop on Real-time Ada workshop - IRTAW '02, 2002

The paper proposes a model for specific Ada structures that can be integrated into our methodolog... more The paper proposes a model for specific Ada structures that can be integrated into our methodology for modeling and performing schedulability analysis in the development phases of distributed real-time applications written in Ada 95 and using its Annexes D and E. This methodology is based on independently modeling the platform, the logical components used, and the real-time situations of the application itself (real-time transactions, workload or timing requirements). The specific models presented in the paper provide support for the automated analysis of local and remote access to distributed services; hence, if a procedure of a remote call interface is invoked from a component assigned to a remote node, the corresponding communication model (with marshalling, transmission, dispatching, and unmarshalling of messages) is implicitly integrated into the overall model that is being analyzed.

Lecture Notes in Computer Science

The concept of interface in Ada 2005 significantly facilitates its usage as the basis for a softw... more The concept of interface in Ada 2005 significantly facilitates its usage as the basis for a software components technology. This technology, taking benefit of the resources that Ada offers for real-time systems development, would be suitable for component-based real-time applications that run on embedded platforms with limited resources. This paper proposes a model based technology for the implementation of distributed real-time component-based applications with Ada 2005. The proposed technology uses the specification of components and the framework defined in the LwCCM standard, modifying it with some key features that make the temporal behaviour of the applications executed on it, predictable, and analysable with schedulability analysis tools. Among these features, the dependency on CORBA is replaced by specialized communication components called connectors, the threads required by the components are created and managed by the environment, and interception mechanisms are placed to control their scheduling parameters in a per-transaction basis. This effort aims to lead to a new IDL to Ada mapping, a prospective standard of the OMG.

Lecture Notes in Computer Science, 2008

This paper proposes a technology for the development of distributed real-time component-based app... more This paper proposes a technology for the development of distributed real-time component-based applications, which takes advantage of the features that Ada offers for the development of applications with predictable temporal behaviour, and which can be executed in embedded platforms with limited resources. The technology uses the Deployment and Configuration of Component-based Distributed Applications Specification of the OMG for describing the components, the execution platforms and the applications. The framework defined in the Lightweight CCM standard of the OMG is taken as the basis of the internal architecture of the components and the applications. It has been extended with a number of features to make the temporal behaviour of the applications predictable. Among these extensions, the usage of CORBA has been replaced by special distributed components, called connectors, which implement the interaction between components by means of predictable and customizable communication services. Besides, special mechanisms have been introduced in the environment to make the threading characteristics of the components configurable. The technology fixes the responsibilities and the knowledge required by each actor involved in the component-based development process, and for each of them it defines the input and output artifacts that they have to manage.

2009 35th Euromicro Conference on Software Engineering and Advanced Applications, 2009

This paper presents a strategy to include temporal behaviour metadata in the descriptors of softw... more This paper presents a strategy to include temporal behaviour metadata in the descriptors of software components in order to develop hard real-time component-based distributed applications, keeping the opacity and composability features that are inherent to the components paradigm. The Deployment and Configuration of Component-based Distributed Applications Specification of the OMG has been extended to include and manage the information that is required to design, analyse, and configure component-based applications with hard real-time requirements. The realtime data added to a component interface enable the application designers to validate scheduling and design decisions without any knowledge of the component's code. Besides, real-time reusable and composable analysis models, developed according to a concrete modelling methodology, are added to each implementation of the component interface. In the context of a concrete application, they are processed by tools to generate the complete real-time analysis model of the application, which is used to evaluate the configuration parameters that guarantee its schedulability.