Seyed Hosein Attarzadeh Niaki

Co-simulation of embedded systems in a heterogeneous MoC-based modeling framework

New design methodologies and modeling frameworks are required to provide a solution for integrating legacy code and IP models in order to be accepted in the industry. To tackle this problem, we introduce the concept of wrappers in the context of a formal heterogeneous embedded system modeling framework. The formalism is based on the language-independent concept of models of computation. Wrappers enable the framework to co-simulate/co-execute with external models which might be legacy code, an IP block, or an implementation of a partially refined system. They are defined formally in order to keep the analyzability of the original framework and also enable automations such as generation of model wrappers and co-simulation interfaces. As a proof of concept, three wrappers for models in different abstraction levels are introduced and implemented for two case studies.

An automated parallel simulation flow for heterogeneous embedded systems

Simulation of complex embedded and cyber-physical systems requires exploitation of the computation power of available parallel architectures. Current simulation environments either do not address this parallelism or use separate models for parallel simulation and for analysis and synthesis, which might lead to model mismatches. We extend a formal modeling framework targeting heterogeneous systems with elements that enable parallel simulations. An automated flow is then proposed that starting from a serial executable specification generates an efficient MPI-based parallel simulation model by using a constraint-based method. The proposed flow generates parallel models with acceptable speedups for a representative example.

Towards a Modelling and Design Framework for Mixed-Criticality SoCs and Systems-of-Systems

Mixed-criticality system (MCS) design is an emerging discipline, which has been identified as a core foundational concept in fields such as cyber-physical systems. The hard real-time design community has pioneered the contributions to MCS design, extending scheduling theory to consider mixed-criticalities and the impact of on-chip and off-chip communication infrastructures. However, the development of MCS design methodologies capable to provide safe and efficient solutions for complex applications and platforms in an acceptable design time demands a more interdisciplinary approach. This paper is a first step towards such an approach in the development of MCS design methodologies. The paper first identifies main design disciplines to be involved in MCS design, both at SoC and system-of-systems (SoS) scales. Then, the paper proposes a core ontology for modelling a mixed-criticality system at both SoC scale (MCSoC) and SoS scale (MCSoS). Finally, the paper introduces a set of aspects required for MCS design which have been identified as open and challenging attending the overviewed state-of-the-art.

Design space exploration for field programmable compressor trees

The Field Programmable Compressor Tree (FPCT) is a programmable compressor tree (e.g., a Wallace or Dadda Tree) intended for integration in an FPGA or other reconfigurable device. This paper presents a design space exploration (DSE) method that can be used to identify the best FPCT architecture for a given set of arithmetic benchmark circuits; in practice, an FPGA vendor can use the design space exploration to tailor the FPCT to meet the needs of the most important benchmark circuits of the vendors largest-volume clients. One novel feature of the DSE is the introduction of a metric called I/O utilization; we found that I/O utilization has a strong correlation with both the critical path delay and area of the benchmark circuits under study. Pruning the search space using I/O utilization allowed us to reduce significantly the number of FPCTs that must be synthesized and evaluated during the DSE, while giving high confidence that the best architectures are still explored. The DSE was applied to seven small-to-medium range benchmark circuits; one FPCT architecture was found that was 30% faster than the second best in terms of critical path delay, and only 3.34% larger than the smallest.

Automatic Generation of Virtual Prototypes from Platform Templates

Virtual Prototypes (VPs) provide an early development platform to embedded software designers when the hardware is not ready yet and allows them to explore the design space of a system, both from the software and architecture perspective. However, automatic generation of VPs is not straightforward because several aspects such as the validity of the generated platforms and the timing of the components needs to be considered. To address this problem, based on a framework which characterizes predictable platform templates, we propose a method for automated generation of VPs which is integrated into a combined design flow consisting of analytic and simulation based design-space exploration. Using our approach the valid TLM-2.0-based simulated VP instances with timing annotation can be generated automatically and used for further development of the system in the design flow. We have demonstrated the potential of our method by designing a JPEG encoder system.

Heterogeneous system-level modeling for small and medium enterprises

The design of todays electronic embedded systems is an increasingly complicated task. This is especially problematic for Small and Medium Enterprises (SMEs) which have limited resources. In this work, we identify a set of common design practices used in industry, with a special focus on problems faced by smaller companies, and formulate them as design scenarios. We show how SMEs can benefit from a system-level design approach by customizing a formal heterogeneous system modeling framework for each scenario. The applicability of this approach is demonstrated by two industrial use cases, an impulse-radio radar and a UART-based protocol.