Functional and Object-Oriented Views in Embedded Software Modeling

The main aim of this article is to discuss how the functional and the object-oriented views can be inter-played in order to model the various modeling perspectives of an embedded system. We discuss if the object-oriented modeling paradigm, most likely the predominant one to develop nowadays software, in the broader sense of the term, is also adequate for modeling embedded software and how it must be conjugated with the functional paradigm. More specifically, we present how Data Flow Diagrams (DFDs), the main diagram in the traditional structured methods, can be integrated in an object-oriented development strategy based on the Unified Modeling Language (UML).CIMO - HH-02-383; Fundação para a Ciência e Tecnologia; Fundo Europeu de Desenvolvimento Regional - Project METHODES: Methodologies and Tools for Developing Complex Real-Time Embedded Systems (POSI/37334/CHS/2001)

Tool Support for DFD-UML Model-Based Transformations

This paper presents a model-based approach that combines the data-flow and object-oriented computing paradigms to model embedded systems. The rationale behind the approach is that both views are important for modelling purposes in embedded systems environments, and thus a combined and integrated usage is not only useful, but also fundamental for developing complex systems. We also show that by using models we were able to implement automated transformations between different views of the system under design. We exemplify the approach with an IPv6 router case study.HPY Research Foundation; CIMO - HH-02-383; Fundação para a Ciência e Tecnologia; Fundo Europeu de Desenvolvimento Regional - Project METHODES: Methodologies and Tools for Developing Complex Real-Time Embedded Systems (POSI/37334/CHS/2001)

Content Scheduling in Multimedia Interactive Mobile Games

In this paper, we study how to implement interactive multimedia services using a DVB-H broadcast channel combined with a point-to-point channel, such as 3G or GPRS. We study the problem in the context of a location-based interactive mobile game. The technical challenge is to schedule the sending of data over the broadcast channel while maintaining Quality-of-Service, that is, sending the right data to the right user at the right time to provide a seamless interactive experience. We explore design issues and problems related to the scheduling of content in the game, present a usecase study to describe scheduling problems and propose a content scheduling algorithm to solve these problems. Moreover, we provide a simulation of the system and the experimental results to show how different game parameters influence the in-time delivery of the multimedia content to the players. We conclude that most of the problems involved with our approach can be expressed as the problem of defining delivery deadlines for a scheduling algorithm

Interfacing and scheduling legacy code within the Canals framework

International audienceThe need for understanding how to distribute computations across multiple cores, have obviously increased in the multi-core era. Scheduling the functional blocks of an application for concurrent execution requires not only a good understanding of data dependencies, but also a structured way to describe the intended scheduling. In this paper we describe how the Canals language and its scheduling framework can be used for the purpose of scheduling and executing legacy code. Additionally a set of translation guidelines for translating RVC-CAL applications into Canals are presented. The proposed approaches are applied to an existing MPEG-4 Simple Profile decoder for evaluation purposes. The inverse discrete cosine transform (IDCT) is accelerated by the means of OpenCL

Power-Aware HEVC Decoding with Tunable Image Quality

International audienceA high pressure is put on mobile devices to support increasingly advanced applications requiring more processing capabilities. Among those, the emerging High Efficiency Video Coding (HEVC) provides a better video quality for the same bit rate than the previous H.264 standard. A limitation in the usability of a mobile video playing device is the lack of support for guaranteeing stand-by time and up time for battery driven devices. The Green Metadata initiative within the MPEG standard was launched to address the power saving issues of the decoder and defines the technology requirements. In this paper, we propose a HEVC decoder with tunable decoding quality levels for maximum power savings as suggested in the scope of the Green Metadata initiative. Our experiments reveal that the modified HEVC video decoder can save up to 28 % of power consumption in real-world platforms while keeping better quality than decoding with H.264

Energy Efficiency and Performance Management of Parallel Dataflow Applications

International audienceParallelizing software is a popular way of achieving high energy efficiency since parallel applications can be mapped on many cores and the clock frequency can be lowered. Perfect parallelism is, however, not often reached and different program phases usually contain different levels of parallelism due to data dependencies. Applications have currently no means of expressing the level of parallelism, and the power management is mostly done based on only the workload. In this work, we provide means of expressing QoS and levels of parallelism in applications for more tight integration with the power management to obtain optimal energy efficiency in multi-core systems. We utilize the dataflow framework PREESM to create and analyze program structures and expose the parallelism in the program phases to the power management. We use the derived parameters in a NLP (NonLinear Programming) solver to determine the minimum power for allocating resources to the applications

Indoor positioning system for movement path analysis in healthcare institutions

In this paper, we describe an indoor positioning system designed to provide data on the movement patterns of hospital personnel. The data collection is ongoing and part of a larger study project, which aims to evaluate the impact of an information system implemented in a hospital setting. The indoor positioning system was designed to be non-intrusive and straightforward to deploy in multiple hospitals, while requiring minimal existing infrastructure. To this end, the system is based on battery-powered Bluetooth beacons, and mobile phones measuring the signal strength of the beacons to position their bearers. This paper describes the design and implementation of the system. We analyze the positioning accuracy of the system in order to evaluate its fitness for purpose. Based on the results, the system is suitable for short-term deployments due to its low cost and ease of installation.  In this paper, we describe an indoor positioning system designed to provide data on the movement patterns of hospital personnel. The data collection is ongoing and part of a larger study project, which aims to evaluate the impact of an information system implemented in a hospital setting. The indoor positioning system was designed to be non-intrusive and straightforward to deploy in multiple hospitals, while requiring minimal existing infrastructure. To this end, the system is based on battery-powered Bluetooth beacons, and mobile phones measuring the signal strength of the beacons to position their bearers. This paper describes the design and implementation of the system. We analyze the positioning accuracy of the system in order to evaluate its fitness for purpose. Based on the results, the system is suitable for short-term deployments due to its low cost and ease of installation

Rialto 2.0: A Language for Heterogeneous Computations

International audienceModern embedded systems are often heterogeneous in that their design requires several description paradigms, based on different models of computation and concurrency (MoCCs). In this paper we present Rialto, a formal language intended at expressing computations in several MoCCs. The distinguishing features of Rialto and its implementation are 1) A formal semantics: the language is formalized using SOS (structured operational semantics) rules; 2) Encapsulation of models of computation into policies: we thus distinguish between the syntactic elements of the language (parallelism, interrupts) and its semantics; 3) efficient implementation algorithms. Policies are expressed in the language itself, which allows for more expressive power and a sounder semantics

Handling Real-World Context Awareness, Uncertainty and Vagueness in Real-Time Human Activity Tracking and Recognition with a Fuzzy Ontology-Based Hybrid Method

Human activity recognition is a key task in ambient intelligence applications to achieve proper ambient assisted living. There has been remarkable progress in this domain, but some challenges still remain to obtain robust methods. Our goal in this work is to provide a system that allows the modeling and recognition of a set of complex activities in real life scenarios involving interaction with the environment. The proposed framework is a hybrid model that comprises two main modules: a low level sub-activity recognizer, based on data-driven methods, and a high-level activity recognizer, implemented with a fuzzy ontology to include the semantic interpretation of actions performed by users. The fuzzy ontology is fed by the sub-activities recognized by the low level data-driven component and provides fuzzy ontological reasoning to recognize both the activities and their influence in the environment with semantics. An additional benefit of the approach is the ability to handle vagueness and uncertainty in the knowledge-based module, which substantially outperforms the treatment of incomplete and/or imprecise data with respect to classic crisp ontologies. We validate these advantages with the public CAD-120 dataset (Cornell Activity Dataset), achieving an accuracy of 90.1% and 91.07% for low-level and high-level activities, respectively. This entails an improvement over fully data-driven or ontology-based approaches.This work was funded by TUCS (Turku Centre for Computer Science), Finnish Cultural Foundation, Nokia Foundation, Google Anita Borg Scholarship, CEI BioTIC Project CEI2013-P-3, Contrato-Programa of Faculty of Education, Economy and Technology of Ceuta and Project TIN2012-30939 from National I+D Research Program (Spain). We also thank Fernando Bobillo for his support with FuzzyOWL and FuzzyDL tools