Papers by Alejandro Alonso
Embedded Software and …, May 25, 2009
Media processing in high-quality multimedia embedded systems (HQMES) has real-time constraints. T... more Media processing in high-quality multimedia embedded systems (HQMES) has real-time constraints. Timely processing and rendering of video frames and audio samples is essential to meet user expectations. The nature of incoming media suffers unforeseen variations which have different resource requirements. Therefore, HQMES have to integrate policies for efficiently and smoothly adapting to these changes. Mode change protocols allow applications to switch their state (for instance, to transition from one quality level to ...
Safety critical applications and hard real-time profile for Java: a case study in avionics
ABSTRACT Despite Java's initial promise of providing a reliable and cost-effecti... more ABSTRACT Despite Java's initial promise of providing a reliable and cost-effective platform-independent environment, the lan-guage appears to be unfavourable in the area of high-integrity systems and real-time systems. To address this issue, the language environment must pro-vide ...
QoS-Based Resource Management for Ambient Intelligence
Future homes will probably be equipped with in-home networks, combining a backbone of wired netwo... more Future homes will probably be equipped with in-home networks, combining a backbone of wired networks and a large number of devices connected through wireless links, to provide a responsive and supportive environment, known as Ambient Intelligence. Many of the applications provided to the user lean heavily on media processing and streaming data. Therefore it is expected that consumer terminals will play an important role in providing new experiences to the users. Most of the devices have to be very cost and power effective, while digital media processing is able to consume all the resources a device can offer, and more. Typically, the number of applications and the resource needs of the applications change over time. To adapt to these variations, applications have the ability to trade resource usage for quality of service (QoS). QoS based resource management enables these tradeoffs in resource-constrained systems. In this paper we present our QoS approach, and we explore an integrated approach that addresses terminal and network resources, and takes power issues into account.
The IPTES Environment: Support for Incremental Heterogeneous and Distributed Prototyping
Real-time Systems, 1993
This paper summarizes the support for incremental, heterogeneous and distributed prototyping of r... more This paper summarizes the support for incremental, heterogeneous and distributed prototyping of real time systems developed as a part of the IPTES environment. After describing the overall architecture of the environment and related approaches, the paper focuses on the internal levels of the environment. IPTES environment supports the incremental development of Real-Time Systems under a spiral life cycle model. The user starts from a SA/RT description enhanced with an executable VDM dialect for minispecifications. Both parts are converted into high level timed Petri nets (HLTPN). The partition of the model at the SA/RT level is reflected at the HLTPN as distributed subnets. A distributed prototype execution implies the joint execution of distributed subnets. Finally, some parts of the prototype could be substituted by actual target code and executed with the rest of the prototype. This is the concept of heterogeneous prototype supported by IPTES tools. A communication protocol to allow the interchange of information while executing has been designed and implemented in the IPTES environment. A detailed description of the Real Time Object Communication Layer (RTOC), its constituent primitives and internal algorithms is presented. This discussion provides the background to understand the behavior of the High Level Timed Petri Net Kernel (HLTPNK) to execute distributed subnets and the Run Time Adaptation Kernel (RTAK) to control the execution of target code as users of the RTOC. Finally, the method used to generate successive versions of the protocol and kernel modules in order to reduce the risks during the implementaton is outlined.
The lack of documentation of the decisions taken during the development is common to many s o w a... more The lack of documentation of the decisions taken during the development is common to many s o w a r e systems. This makes it diflcult to use the experience in future developments. This picture is worse when dealing with a family of products. The lack of documentation on the design decisions may preclude coherent evolution and development of products. This paper presents a framework for representing and supporting design decisions in the development of product families. The injormation is structured as a DDT (Design Decision Tree), where nodes represent design decisions and branches relate nodes to each other. The access to this information is based on HTML and WWW navigators. A simple case study is presented in order to illustrate the approach and to show its feasibility.
Assessment of Timing Properties of Family Products
This paper presents an approach to obtain the timing implications introduced by variations in new... more This paper presents an approach to obtain the timing implications introduced by variations in new products of a family. This is carried out by building a global RMA model of a system from the individual models of its components. These individual models are integrated according to some interconnection information.
Timing analysis of a generic robot teleoperation software architecture
Control Engineering Practice, 1998
The development of generic software architectures for specific application domains is an effectiv... more The development of generic software architectures for specific application domains is an effective way of reusing software. This was one of the aims in the development of an architecture for teleoperating robots, which can be adapted to deal with different jobs, operational environments and robots. However these kinds of systems have timing requirements. The purpose of this paper is to present a characterization of this architecture, for an analysis of its timing properties using the Rate Monotonic Analysis method. In this ...
The lack of documentation of the decisions taken during the development is common to many s o w a... more The lack of documentation of the decisions taken during the development is common to many s o w a r e systems. This makes it diflcult to use the experience in future developments. This picture is worse when dealing with a family of products. The lack of documentation on the design decisions may preclude coherent evolution and development of products. This paper presents a framework for representing and supporting design decisions in the development of product families. The injormation is structured as a DDT (Design Decision Tree), where nodes represent design decisions and branches relate nodes to each other. The access to this information is based on HTML and WWW navigators. A simple case study is presented in order to illustrate the approach and to show its feasibility.
Iet Software/iee Proceedings - Software, 2008
Safety critical software requires integrating verification techniques in software development met... more Safety critical software requires integrating verification techniques in software development methods. Software architectures must guarantee that developed systems will meet safety requirements and safety analyses are frequently used in the assessment. Safety engineers and software architects must reach a common understanding on an optimal architecture from both perspectives. Currently both groups of engineers apply different modelling techniques and languages: safety analysis models and software modelling languages. The solutions proposed seek to integrate both domains coupling the languages of each domain. It constitutes a sound example of the use of language engineering to improve efficiency in a software-related domain. A model-driven development approach and the use of a platform-independent language are used to bridge the gap between safety analyses (failure mode effects and criticality analysis and fault tree analysis) and software development languages (e.g. unified modelling language). Language abstract syntaxes (metamodels), profiles, language mappings (model transformations) and language refinements, support the direct application of safety analysis to software architectures for the verification of safety requirements. Model consistency and the possibility of automation are found among the benefits.
Uploads
Papers by Alejandro Alonso