System-Level Modeling, Analysis and Code Generation: Object Recognition Case Study

International audienceOne of the most important challenges in complex embedded systems design is developing methods and tools for modeling and analyzing the behavior of application software running on multi-processor platforms. We propose a tool-supported flow for systematic and compositional construction of mixed software/hardware system models. These models are intended to represent, in an operational way, the set of timed executions of parallel application software statically mapped on a multi-processor platform. As such, system models will be used for performance analysis using simulation-based techniques as well as for code generation on specific platforms. The construction of the system model proceeds in two steps. In the first step, an abstract system model is obtained by composition and specific transformations of (1) the (untimed) model of the application software, (2) the model of the platform and (3) the mapping between them. In the second step, the abstract system model is refined into concrete system model, by including specific timing constraints for execution of the application software, according to chosen mapping on the platform. We illustrate the system model construction method and its use for performance analysis and code generation on an object recognition application provided by Hellenic Airspace Industry. This case study is build upon the HMAX models algorithm [RP99] and is looking at significant speedup factors. This paper reports results obtained on different system model configurations and used to determine the optimal implementation strategy in accordance to hardware resources

Pretrial Case Management Under the Amended Rules: Too Many Words for a Good Idea

To cope with the increasing complexity of embedded and cyber-physical system design, different system-level design approaches are proposed which start from abstract models and implement them using design flows with high degrees of automation. However, creating models of such systems and also formulating the mathematical problems arising in these design flows are themselves challenging tasks. A promising approach is the composable construction of these models and problems from more basic entities. Unfortunately, it is non-trivial to propose such compositional formulations today because the current practice in the electronic design automation domain tends to be on using imperative languages and frameworks due to legacy and performance-oriented reasons. This thesis addresses the system design complexity by first promoting proper formalisms and frameworks for capturing models and formulating design-space exploration problems for electronic system-level design in a declarative style; and second, propose realizations based on the industrially accepted languages and frameworks which hold the interesting properties such as composability and parallelism. For modeling, ForSyDe, a denotational system-level modeling formalism for heterogeneous embedded systems is chosen, extended with timed domains to make it more appropriate for capturing cyber-physical systems, and mapped on top of the IEEE standard system design language SystemC. The realized modeling framework, called ForSyDe-SystemC, can be used for modeling systems of heterogeneous nature and their composition to form more sophisticated systems and also conducting parallel and distributed simulation for boosting the simulation speed. Another extension to ForSyDe, named wrapper processes, introduces the ability to compose formal ForSyDe models with legacy IP blocks running in external execution environments to perform a heterogeneous co-simulation. In platform-based design flows, the correct and optimal mapping of an application model onto a flexible platform involves solving a hard problem, named design space exploration. This work proposes Tahmuras, a constraint- based framework to construct generic design space exploration problems as the composition of three individual sub-problems: the application, the platform, and the mapping and scheduling problems. In this way, the model of the design space exploration problem in Tahmuras is automatically generated for each combination of application semantics, target platform, and mapping and scheduling policy simply by composing their respective problems. Using constraint programming, problems can be modeled in a declarative style, while they can be solved in a variety of different styles, including imperative solving heuristics commonly used to solve difficult problems. Efficient parallel solvers exists for constraint programming. Den ökande komplexiteten är en stor utmaning för konstruktionen av framtida inbyggda system. För att möta utmaningen utvecklas nu konstruktionsmetoder som har som mål att starta från en abstrakt modell och att generera en implementering genom ett konstruktionsflöde med hög automatiseringsgrad. Dessvärre är dock skapandet av abstrakta systemmodeller och formaliseringen av de relaterade matematiska problemen i sig ett mycket utmanande problem. Konstruktion genom komposition av basenheter är en lovande idé, men tyvärr är det väldigt svårt att introducera metoden i dagens industriella konstruktionsflöden på grund av imperativa programmeringsspråk och ett gammalt arv i form av existerande kodbas och äldre konstruktioner. Avhandlingen adresserar komplexiten inom systemkonstruktion genom att föreslå passande formalismer för att uttrycka modeller i en deklarativ stil och angripa problemet att hitta en passande implementering. Dessutom visar avhandlingen hur dessa formalismer kan realiseras i en form som kan användas i ett industriellt sammanhang utan att förlora formalismens viktiga grundläggande egenskaper som komposition och parallelism. Modelleringen använder och utökar ForSyDe, en konstruktionsmetod för heterogena inbyggda system. Tilläggen består av en modelleringsmodell som kan fånga specifika egenskaper hos heterogena inbyggda system, samt en implementering av ForSyDe i SystemC, ett industriellt modelleringsspråk som är standardiserat av IEEE. Den nya utvecklingsmiljön, ForSyDe-SystemC, kan användas för att modellera inbyggda system, komponera systemmodeller till större system, samt möjliggör genomförandet av parallella och distribuerade simuleringar med medföljande hög simuleringshastighet. Avhandlingen introducerar också “wrapper”-konceptet i ForSyDe som möjliggör integrationen av existerande modeller och system som en del av en formell ForSyDe-modell och deras co-simulering. ForSyDe-SystemC har använts inom EU-projekt av industriella partner för modellering av egna system. Att hitta en korrekt och effektiv implementering av en abstrakt systemmodell är målet inom aktiviteten “design space exploration” (DSE) som är ett svårt problem för parametriserbara och flexibla plattformar. Avhandlingen presenterar två generationer av Tahmuras, som är baserade på villkorsprogrammering och har som mål att konstruera DSE-problemet som en komposition av tre olika delproblem: applikation, plattform, och bindning. Ett integrerat DSE-problem kan sedan automatiskt genereras genom en kombination av dessa delproblem. Olika metoder, från heuristisk till komplett sökning, kan användas inom villkorsprogrammering för att lösa DSE-problemet. För att visa Tahmuras potential har DSE-metoden validerats med hjälp av olika systemapplikationer av skilda tidsegenskaper och olika plattformar. QC 20141117</p

A component-oriented programming framework for developing embedded mobile robot software using PECOS model

A practical framework for component-based software engineering of embedded real-time systems, particularly for autonomous mobile robot embedded software development using PECOS component model is proposed The main features of this framework are: (1) use graphical representation for components definition and composition; (2) target C language for optimal code generation with small micro-controller; and (3) does not requires run-time support except for real-time kernel. Real-time implementation indicates that, the PECOS component model together with the proposed framework is suitable for resource constrained embedded systems

Middleware Technologies for Cloud of Things - a survey

The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

Middleware Technologies for Cloud of Things - a survey

The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

Schedulability analysis of timed CSP models using the PAT model checker

Timed CSP can be used to model and analyse real-time and concurrent behaviour of embedded control systems. Practical CSP implementations combine the CSP model of a real-time control system with prioritized scheduling to achieve efficient and orderly use of limited resources. Schedulability analysis of a timed CSP model of a system with respect to a scheduling scheme and a particular execution platform is important to ensure that the system design satisfies its timing requirements. In this paper, we propose a framework to analyse schedulability of CSP-based designs for non-preemptive fixed-priority multiprocessor scheduling. The framework is based on the PAT model checker and the analysis is done with dense-time model checking on timed CSP models. We also provide a schedulability analysis workflow to construct and analyse, using the proposed framework, a timed CSP model with scheduling from an initial untimed CSP model without scheduling. We demonstrate our schedulability analysis workflow on a case study of control software design for a mobile robot. The proposed approach provides non-pessimistic schedulability results