EDALab (Italy)

Cyber-Physical Systems consist of cyber components controlling physical entities. Their development involves different engineering disciplines, that use different models, written in languages with different semantics. A coupled simulation of these models is of prime importance to rapidly understand the emerging system behavior. The coupling of the simulations is realized by a coordinator that conveys data and ensures time consistency between the different models/simulators. Existing coordinators are usually time triggered. In this paper we show that time-triggered coordinators may introduce poor performance and accuracy (both temporal and functional) when used to co-simulate cyber-physical models. Therefore, we propose a new coordinator mixing time- and event-triggered mechanisms. We validated the approach in the context of the FMI standard for co-simulation. To make possible the writing of the new coordinators, we implemented backward compatible extensions to the FMI API. Also, we implemented a new FMI exporter in an industrial tool.

The future smart power grid will consist of an unlimited number of smart devices that communicate with control units to maintain the grid's sustainability, efficiency, and balancing. In order to build and verify such controllers over a large grid, a scalable simulation environment is needed. This paper presents an open source smart grid simulator (SGSim). The simulator is based on open source SystemC Network Simulation Library (SCNSL) and aims to model scalable smart grid applications. SGSim has been tested under different smart grid scenarios that contain hundreds of thousands of households and appliances. By using SGSim, different smart grid control strategies and protocols can be tested, validated and evaluated in a scalable environment.

This work provides a taxonomy of abstraction levels and design domains of a smart system, for analyzing the support of simulation/co-simulation and the effect of homogeneity/heterogeneity on simulation. The paper presents also flows and tools that can be exploited to gain homogeneous simulation. The overall approach is applied to a complex industrial case study.

An optical CMOS heart rate sensor that processes the photoplethysmographic signal was designed and fabricated in Austriamicrosystems 0.35μm CMOS process. The sensor consists of photodiode, transimpedance amplifier, analogue bandpass filters, analogue-to-digital converters, digital signal processor, and a timing circuit that is used to modulate the external light-emitting diodes. The mixed-signal simulation has been carried out to validate the system design. With modulated green light source and integrated lock-in detection the sensor is capable of extracting clean photoplethysmographic signal when it is operated in reflectance mode. The heart rate output was compared with commercial devices and they show a good agreement. The chip-level integration enables a small foot print of the design and makes it suitable for the applications of ambulatory monitoring.

Smart systems implement the leading technology advances in the context of embedded devices. Current design methodologies are not suitable to deal with tightly interacting subsystems of different technological domains, namely analog, digital, discrete and power devices, MEMS and power sources. The effects of interaction between components and with the environment must be modeled and simulated at system level to achieve high performance. Focusing on the digital domain, additional design constraints have to be considered as a result of the integration of multi-domain subsystems in a single device. The main digital design challenges, combined with those emerging from the heterogeneous nature of the whole system, directly impact on performance and on propagation delay of the digital component. This paper proposes a design approach to enhance the RTL model of a given digital component for the integration in smart systems, and a methodology to verify the added features at system-level. The design approach consists of augmenting the RTL model through the automatic insertion of delay sensors, which can detect and correct timing failures. The augmented model is abstracted to SystemC TLM and, then, mutants (i.e., code mutations for emulating timing failures) are automatically injected into the model. Experimental results demonstrate the applicability of the proposed design and verification methodology and the effectiveness of the simulation performance.

Smart systems implement the leading technology advances in the context of embedded devices. Current design methodologies are not suitable to deal with tightly interacting subsystems of different technological domains, namely analog, digital, discrete and power devices, MEMS and power sources. The effects of interaction between components and with the environment must be modeled and simulated at system level to achieve high performance. Focusing on the digital domain, additional design constraints have to be considered as a result of the integration of multi-domain subsystems in a single device. The main digital design challenges, combined with those emerging from the heterogeneous nature of the whole system, directly impact on performance and on propagation delay of the digital component. This paper proposes a design approach to enhance the RTL model of a given digital component for the integration in smart systems, and a methodology to verify the added features at system-level. The design approach consists of augmenting the RTL model through the automatic insertion of delay sensors, which can detect and correct timing failures. The augmented model is abstracted to SystemC TLM and, then, mutants (i.e., code mutations for emulating timing failures) are automatically injected into the model. Experimental results demonstrate the applicability of the proposed design and verification methodology and the effectiveness of the simulation performance.

This work proposes an advanced methodology based on an open source virtual prototyping framework for verification of complex Heterogeneous Embedded Systems (HES). It supports early rapid modelling of complex HES through smooth refinements, an open interface based on IP-XACT extensions for secure composition of HES components, and automatic testbench generation over different abstraction levels.

Ambient intelligence and ubiquitous computing are the center of a great deal of attention because of their promise to bring benefits for end-users, higher revenues for manufacturers and new challenges for researchers [1]. The key aspects of these applications are their distributed nature and the presence of very limited HW resources, as in case of WSNs. Their wide adoption requires interoperability across different manufacturers, simplification of application development, simulation tools for functional validation and the fulfilment of tight HW/SW constraints.