Master Interface for On-Chip Hardware Accelerator Burst Communications

International audienceWe explain a systematic way of interfacing data-flow hardware accelerators (IP) for their integration in a system on chip. We abstract the communication behaviour of the data flow IP so as to provide basis for an interface generator. Then we measure the throughput obtained for different architectures of the interface mechanism by a cycle accurate bit accurate simulation of a SoC integrating a data-flow IP. We show in which configuration the optimal communication scheme can be reached

Cycle Accurate Simulation Model Generation for SoC Prototyping

RR 2004-18, ENS-Lyon, 24 pagesWe present new results concerning the integration of high level designed ips into a complete System on Chip. We first introduce a new compu- tation model that can be used for cycle accurate simulation of register transfer level synthesized hardware. Then we provide simulation of a SoC integrating a data-flow ip synthesized with MMAlpha and the So- cLib cycle accurate simulation environment. This integration also vali- dates an efficient generic interface mechanism for data-flow ips

Efficient on-chip communications for data-flow IPs

International audienceWe explain a systematic way of interfacing data-flow hardware accelerators (IP) for their integration in a system on chip. We abstract the communication behaviour of the data flow IP so as to provide basis for an interface generator. We also explain which parameter this interface generator has to take into account. We validate our interface mechanism by a cycle accurate bit accurate simulation of a SoC integrating a data-flow ip

Demonstration of worldsens: a fast prototyping and performance evaluation of wireless sensor network applications & protocols

International audienceWe present Worldsens, a complete environment for fast prototyping of wireless sensor protocols and applications. Our environment proposes a full simulation platform with both embedded software instruction and radio packet accuracy. We propose a demonstration including a full software design, simulation, performance estimation and deployment on a set of nodes within the same design environment. Through these first experimentations, we show that accurate sensor network simulation is feasible and that complex application design and deployment is affordable

Fast and Accurate Embedded Systems Energy Characterization Using Non-intrusive Measurements

International audienceIn this paper we propose a complete system energy model based on non-intrusive measurements. This model aims at being integrated in fast cycle accurate simulation tools to give energy consumption feedback for embedded systems software design. Estimations takes into account the whole system consumption including peripherals. Experiments on a complex ARM9 platform show that our model estimates are in error by less than 10% from real system consumption, which is precise enough for source code application design, while simulation speed remains fast

On Frequency Optimisation for Power Saving in WSNs: Finding Optimum Hardware Timers Frequencies

Wireless Sensor Networks research and demand are now in full expansion, since people came to understand these are the key to a large number of issues in industry, commerce, home automation, healthcare, agriculture and environment, monitoring, public safety etc. One of the most challenging research problems in sensor networks research is power awareness and power-saving techniques. In this master's thesis, we have studied one particular power-saving technique, i.e. frequency scaling. In particular, we analysed the close relationship between clock frequencies in a microcontroller and several types of constraints imposed on these frequencies, e.g. by other components of the microcontroller, by protocol specifications, by external factors etc. Among these constraints, we were especially interested in the ones imposed by the timer service and by the serial ports' transmission rates. Our efforts resulted in a microcontroller configuration management tool which aims at assisting application programmers in choosing microcontroller configurations, in function of the particular needs and constraints of their application

Embedded Systems Energy Characterization using non-Intrusive Instrumentation

Research Report RR2006-37, LIP - ENS LyonThis research report presents a non intrusive methodology for building embedded systems energy consumption models. The method is based on measurement on real hardware in order to get a quantitative approach that takes into account the full architecture. Based on these measurements, data are grouped into class of instructions and events. These classes can then be reused in software simulators and in high-level source code transformation cost functions for optimizing compilers. The computed power model is much more simpler than previous power models while being accurate at the platform level. The methodology is illustrated using experimental results made on an ARM Integrator platform for which an accurate and full system energy model is build

Worldsens: development and prototyping tools for application specific wireless sensors networks

International audienceIn this paper we present Worldsens, an integrated environment for development and rapid prototyping of wireless sensor network applications. Our environment relies on software simulation to help the designer during the whole development process. The refinement is done starting from the high level design choices down to the target code implementation, debug and performance analysis. In the early stages of the design, high level parameters, like for example the node sleep and activity periods, can be tuned using WS-Net, an event driven wireless network simulator. WSNet uses models for applications, protocols and radio medium communication with a parameterized accuracy. The second step of the sensor network application design takes place after the hardware implementation choices. This second step relies on the WSim cycle accurate hardware platform simulator. WSim is used to debug the application using the real target binary code. Precise performance evaluation, including real-time analysis at the interrupt level, are made possible at this low simulation level. WSim can be connected to WSNet, in place of the application and protocol models used during the high level simulation to achieve a full distributed application simulation. WSNet and WSNet+WSim allow a continuous refinement from high level estimations down to low level real-time validation. We illustrate the complete application design process using a real life demonstrator that implements a hello protocol for dynamic neighborhood discovery in a wireless sensor network environment

A wireless sensor network to measure the health care workers exposure to tuberculosis

International audienceIn parallel to the advances in modern medicine, health sciences and public health policy, epidemic models aided by computer simulations and information technologies offer an important alternative for the understanding of transmission dynamics and epidemic patterns. In this paper, we focus on the first steps that may lead towards the design of epidemic models, i.e. the measure and analysis of interactions within a closed socio-professional context. More precisely, this project was motivated by the study of the Health Care Workers (HCWs) exposure to tuberculosis in their work environment. Despite the progresses in treatment and prevention, tuberculosis remains a disease in expansion and represents the third cause of death by infectious pathologies in the world. In the health care context, if the transmission is globally controlled, the HCWs exposure remains obscure. Individual factors associated to the contamination of HCWs in their work environment are not precisely known. Our study focus on the evaluation of the intensity and the frequency of contacts between tuberculosis infected patients and HCWs. To gather this information, classical methods consist in performing audits, consulting medical and administrative files or using self-reports of conversations and trusting HCW souvenirs. All these methods are time-consuming, subject to memory failures and interpretations. As an alternate method, we have chosen to dedicate a Wireless Sensor Network (WSN) to gather these interactions inside a Service of Infectious and Tropical Diseases (Bichat-Claude Bernard Hospital, Paris) and a Service of Pneumology (La Piti ´ e Salp ´ etri ` ere Hospital, Paris). Within the two services, each room has been equipped with a sensor node and each HCW carries an autonomous sensor during his presence in the service. An important characteristic of this measurement campaign is that it was performed in a closed environment, over a closed population and during a large continuous period of time. That is, the presence of all HCWs of the units was monitored in all patient rooms, 24/7 during a three months period. In addition to the experimental measure system description, this paper main contributions are the analysis and characterization of this huge and unique data set describing a complex dynamic interaction network, and the impact study of the measurement process bias on the network dynamic. The analyze of large dynamic in situ interaction networks provides an opportunity to study dynamical processes occurring on dynamical networks, such as spreading or epidemical processes, taking into account the dynamics both on and of the network structure

Demonstration of worldsens: a fast prototyping and performance evaluation of wireless sensor network applications & protocols

International audienceWe present Worldsens, a complete environment for fast prototyping of wireless sensor protocols and applications. Our environment proposes a full simulation platform with both embedded software instruction and radio packet accuracy. We propose a demonstration including a full software design, simulation, performance estimation and deployment on a set of nodes within the same design environment. Through these first experimentations, we show that accurate sensor network simulation is feasible and that complex application design and deployment is affordable