Testing and calibration of smart pebble for river bed sediment transport monitoring

The Smart Pebble (smart particle), SP, has been developed for the past two years to monitor sediment transport in riverbeds. The implementation is based on use of small size and low cost acceleration and angular motion sensors. In this stage, the project is focused on calibrating and testing the final version of the SP as well as its packaging in a 4-cm diameter spherical package. The calibration was done in two stages; individual sensor calibration and complete system calibration. The complete SP unit was tested under linear motions generated by a shake table, and 2D rotational motions using two manually controlled servomotors. Offline digital signal conditioning was done in MATLAB. The preliminary results show that the system has relatively large amplitude error due to low sampling frequency. Experiments conducted by sampling a 1-Hz sinusoidal signal at different rates show that to keep the amplitude error of the system under 5% the sampling rate has to be at least 10 times the maximum bandwidth of the signals acquired from sensors

Detecting Turns And Correcting Headings Using Low-Cost INS

Unlike industrial-grade Inertial Navigation Sensors (INSs) that can provide credible tracking performance, more affordable consumer-grade low-cost INSs produce drifts in heading angles and positions that result in a poor tracking accuracy. Researchers have proposed drift correction methods that attempt to attenuate the drifts when walking straight along the dominant directions is detected. While determining the type of a pedestrian's walk is essential before the heading corrections are made, the current detection techniques heavily rely on thresholding. This paper proposes a novel threshold-less method to detect turns in walking by using pelvic rotation and correct the heading angle based on consumer-grade INSs. The experiments indicate the proposed turn detector and heading correction methods produce very good results which can be applied for future pedestrian tracking, activity recognition or rehabilitation

The SystemJ approach to system-level design

In this paper, we propose a new system-level design language, called SystemJ. It extends Java with synchronous reactive features present in Esterel and asynchronous constructs suitable for modelling globally asynchronous locally synchronous systems. The strength of SystemJ comes from its ability to offer the data processing and encapsulation elegance of Java, Esterel-like reactivity and synchrony, and the asynchronous de-coupling of CSP all within the Java framework. Using standard Java environments, for specification and modelling, or specialised reactive embedded processors, for high performance implementation, the SystemJ design flow is extremely versatile. With the increasing attention that Java gets in embedded systems, SystemJ comes to address data and control, software and hardware, modelling and implementation in a unified manner

A GALS Language for Dynamic Distributed and Reactive Programs

International audienceWe propose a Globally Asynchronous Locally Syn- chronous language DSystemJ for designing dynamic distributed systems. DSystemJ, an extension of the reactive asynchronous SystemJ language, enhances it with dynamic creation and process mobility, and uses the Java language for programming sequential data computations. Moreover, DSystemJ is equipped with a formal semantics, which allows, formal system specifi- cation, reasoning, and automatic code generation. Compared to special purpose languages, DSystemJ is better in terms of implementation, scalability, and features. Compared to general purpose languages, DSystemJ is better because it exposes, at the language level, OS features like communication, concurrency, process creation and migration, therefore making it better suited for system level design of complex distributed systems

The DSystemJ programming language for dynamic GALS systems: it's semantics, compilation, implementation, and run-time system

The paper presents a programming language called DSystemJ, for dynamic distributed Globally Asynchronous Locally Synchronous systems (GALS), its formal model, formal syntax and semantics, its compilation and implementation. The language is aimed at dynamic distributed systems, which use socket based communication protocols for communicating between components. DSystemJ allows the creation and control at runtime of asynchronous processes called clock-domains, their mobility on a distributed execution platform, as well as the runtime reconfiguration of the system's functionality and topology. As DSystemJ is based on a GALS model of computation and has formal semantics, it offers very safe mechanisms for implementation of dynamic distributed systems and potential for their formal verification. The principles and details of DSystemJ's compilation, as well as its required runtime support are described. The runtime support is itself implemented in the SystemJ GALS language, which can be considered as a static subset of DSystemJ.Cet article pr´esente un nouveau langage de programmation appel´e DSystemJ, destin´e aux syst`emes r´epartis dynamiques Globalement Asynchrones Localement Synchrones (GALS), ainsi que son mod`ele formel de calcul, sa syntaxe et sa s´emantique formelle, sa compilation et sa mise en oeuvre. Le langage est destin´e `a la conception des syst`emes r´epartis dynamiques, qui utilisent des protocoles de communication bas´es sur les sockets. DSystemJ permet la cr´eation et le contrˆole durant l'ex´ecution de processus asynchrones appel´es clockdomains, leur mobilit´e sur des plateformes d'ex´ecution r´epartie, ainsi que la reconfiguration `a l'ex´ecution des fonctionnalit´es du syst`eme et de sa topologie. Puisque le mod`ele formel de calcul de DSystemJ est bas´e sur le mod`ele GALS et poss`ede une s´emantique formelle, il offre des m´ecanismes tr`es sˆurs pour la mise en oeuvre de syst`emes dynamiques r´epartis et le potentiel pour leur v´erification formelle. Nous donnons les principes et les d´etails de la compilation de DSystemJ ainsi que son environnement de support `a l'ex´ecution. Cet environnement de support est lui-mˆeme mis en oeuvre dans le langage GALS SystemJ, qui peut ˆetre consid´er´e comme un sous-ensemble statique de DSystemJ

A GALS Language for Dynamic Distributed and Reactive Programs

International audienceWe propose a Globally Asynchronous Locally Syn- chronous language DSystemJ for designing dynamic distributed systems. DSystemJ, an extension of the reactive asynchronous SystemJ language, enhances it with dynamic creation and process mobility, and uses the Java language for programming sequential data computations. Moreover, DSystemJ is equipped with a formal semantics, which allows, formal system specifi- cation, reasoning, and automatic code generation. Compared to special purpose languages, DSystemJ is better in terms of implementation, scalability, and features. Compared to general purpose languages, DSystemJ is better because it exposes, at the language level, OS features like communication, concurrency, process creation and migration, therefore making it better suited for system level design of complex distributed systems

The DSystemJ programming language for dynamic GALS systems: it's semantics, compilation, implementation, and run-time system

The paper presents a programming language called DSystemJ, for dynamic distributed Globally Asynchronous Locally Synchronous systems (GALS), its formal model, formal syntax and semantics, its compilation and implementation. The language is aimed at dynamic distributed systems, which use socket based communication protocols for communicating between components. DSystemJ allows the creation and control at runtime of asynchronous processes called clock-domains, their mobility on a distributed execution platform, as well as the runtime reconfiguration of the system's functionality and topology. As DSystemJ is based on a GALS model of computation and has formal semantics, it offers very safe mechanisms for implementation of dynamic distributed systems and potential for their formal verification. The principles and details of DSystemJ's compilation, as well as its required runtime support are described. The runtime support is itself implemented in the SystemJ GALS language, which can be considered as a static subset of DSystemJ.Cet article pr´esente un nouveau langage de programmation appel´e DSystemJ, destin´e aux syst`emes r´epartis dynamiques Globalement Asynchrones Localement Synchrones (GALS), ainsi que son mod`ele formel de calcul, sa syntaxe et sa s´emantique formelle, sa compilation et sa mise en oeuvre. Le langage est destin´e `a la conception des syst`emes r´epartis dynamiques, qui utilisent des protocoles de communication bas´es sur les sockets. DSystemJ permet la cr´eation et le contrˆole durant l'ex´ecution de processus asynchrones appel´es clockdomains, leur mobilit´e sur des plateformes d'ex´ecution r´epartie, ainsi que la reconfiguration `a l'ex´ecution des fonctionnalit´es du syst`eme et de sa topologie. Puisque le mod`ele formel de calcul de DSystemJ est bas´e sur le mod`ele GALS et poss`ede une s´emantique formelle, il offre des m´ecanismes tr`es sˆurs pour la mise en oeuvre de syst`emes dynamiques r´epartis et le potentiel pour leur v´erification formelle. Nous donnons les principes et les d´etails de la compilation de DSystemJ ainsi que son environnement de support `a l'ex´ecution. Cet environnement de support est lui-mˆeme mis en oeuvre dans le langage GALS SystemJ, qui peut ˆetre consid´er´e comme un sous-ensemble statique de DSystemJ