Màrius Montón

Mixed SW/SystemC SoC Emulation Framework

Developing HW modules for standard platforms like PCs or embedded devices requires a complete system emulator availability to detect and fix bugs on developed HW, Operating Systems (OS) drivers and applications. This paper presents a set of plug-ins to an open-source CPU emulator that enables mixed simulations between platforms emulators and hardware (HW) modules described in SystemC. In this paper three plugins for QEMU are described: one for connecting TLM SystemC modules to any bus QEMU emulates, one for connecting SystemC to PCI bus for PC based platform and one plug-in for connecting SystemC to AMBA bus for ARM platforms. With this framework, it is possible to develop OS drivers at the same time HW is developed and final application tested running in this virtual platform.

The Power of Models: Modeling Power Consumption for IoT Devices

Low-energy technologies in the Internet of Things (IoTs) era are still unable to provide the reliability needed by the industrial world, particularly in terms of the wireless operation that pervasive deployments demand. While the industrial wireless performance has achieved an acceptable degree in communications, it is no easy task to determine an efficient energy-dimensioning of the device in order to meet the application requirements. This is especially true in the face of the uncertainty inherent in energy harvesting. Thus, it is of utmost importance to model and dimension the energy consumption of the IoT applications at the pre-deployment or pre-production stages, especially when considering critical factors, such as reduced cost, life-time, and available energy. This paper presents a comprehensive model for the power consumption of wireless sensor nodes. The model takes a system-level perspective to account for all energy expenditures: communications, acquisition and processing. Furthermore, it is based only on parameters that can empirically be quantified once the platform (i.e., technology) and the application (i.e., operating conditions) are defined. This results in a new framework for studying and analyzing the energy life-cycles in applications, and it is suitable for determining in advance the specific weight of application parameters, as well as for understanding the tolerance margins and tradeoffs in the system.

Checkpoint and Restore for SystemC models

We present preliminary work in the field of saving and restoring model state within a SystemC simulation environment. Save and restore (or checkpointing) is a useful technique that can greatly assist target software and simulation model development and debug. In contrast to other approaches that aim at saving and restoring the state of an entire simulation process, we investigate mechanisms by which only the essential simulation state is saved. This makes the checkpoints far more compact, and saved simulation states can be moved between host machines, and be used with updated or completely different simulation models. Our results indicate that SystemC models written to certain coding guidelines can be saved and restored reliably. As a result, virtual platforms and platform components written in SystemC can be made more useful to software developers, and support smarter workflows.

An Open-Source Cloud Architecture for Big Stream IoT Applications

The Internet of Things (IoT) is shaping to a worldwide network of networks consisting of billions of interconnected heterogeneous sensor/actuator-equipped devices (denoted as “things” or “smart objects”), which are expected to exceed 50 billions by 2020. Smart objects, which will be pervasively deployed, are constrained devices with (i) limited processing power and available memory and (ii) limited communication capabilities, in terms of transmission rate and reliability. Future Smart-X applications, such as Smart Cities and Home Automation, will be fostered by the use of standard and interoperable IP-based communication protocols that smart objects are going to implement, by simplifying their development, integration, and deployment. Smart-X applications will significantly differ from traditional Internet services, in terms of: (i) the number of data sources; (ii) rate of information exchange; and, (iii) need for real-time processing. Because of these requirements, such services are denoted as “Big Stream” applications, in order to distinguish them from traditional Big Data applications. In this paper, we present an implementation of a novel Cloud architecture for Big Stream applications based on standard protocols and open-source components, which provides a scalable and efficient processing platform for IoT applications, designed to be open and extensible and to guarantee minimal latency between data generation and consumption. We also provide a performance evaluation based on experimentation in a real-world Smart Parking scenario, to assess the feasibility and scalability of the proposed architecture.

Checkpointing for Virtual Platforms and SystemC-TLM

Integrating simulation models created using different simulation systems is a common problem when constructing virtual platforms. Different companies and different departments can create models, and virtual platforms for different purposes using different tools. There are also existing models that need to be integrated into new tools, or the other way around. The simulators can be quite different in details, even in the case of transaction-level models. We present work in integrating SystemC transaction-level models into two typical full-system simulation environments, QEMU and Simics. We present issues in reconciling the semantics of the different platforms, and our proposed solutions. In the Simics integration, we additionally enable checkpointing in the models, based on the Simics checkpoint mechanism.

Balancing Power Consumption in IoT Devices by Using Variable Packet Size

Currently, IoT devices are becoming more and more popular, being deployed in different scenarios such as monitoring the power consumption of a house or the state of an outdoor parking spot. These networks tend to be densely populated by a huge amount of sensors that send really short messages. Given these characteristics, their main problem is the great variability and unpredictability of battery lifetime, when they cannot be plugged to a power outlet. In this paper, we analyze the mote behaviour on a real IoT network and use the extracted data to propose a mechanism to distribute the power consumption more equally between all motes, regardless the number of messages each one sends. This new proposal decreases the numbers of interventions required to replace batteries, minimizing costs and increasing network lifetime.

The e-Sentencias Prototype: A Procedural Ontology for Legal Multimedia Applications in the Spanish Civil Courts

Search, retrieval, and management of multimedia contents are challenging tasks for users and researchers alike. We introduce a software-hardware system for the global management of the multimedia contents produced by Spanish Civil Courts. The ultimate goal is to obtain an automatic classification of images and segments of the audiovisual records that, coupled with textual semantics, allows an efficient navigation and retrieval of judicial documents and additional legal sources. This paper describes our knowledge acquisition process, sets a typology of Spanish Civil hearings as performed in practice, and a preliminary procedural ontology at its actual stage of development (e-Sentencias ontology). A discussion on procedural, contextual and multimedia ontologies is also provided.

Device-to-device communications in wireless sensor networks

In device-to-device (D2D) communications, devices communicate with each other autonomously without any centralized control and collaborate to gather, share, and forward information in short-range networks such as wireless sensor networks (WSNs), LTE Direct, Wi-Fi Direct, or Bluetooth Low Energy (BLE). D2D communications and networking are a promising concept to improve resource utilization and enhance user quality of experience (QoE) for both licensed and unlicensed spectra. Moreover, D2D communications may extend the network coverage and facilitate new types of wireless peer-to-peer services, while at the same time, increasing energy efficiency of communications. The scope of this Special Issue is in line with recent research advances of D2D communications in WSN. For the current issue, we are pleased to introduce a collection of papers covering a range of topics as follows:

Energy-Aware MPEG-4 Single Profile in HW-SW Multi-Platform Implementation

Developers of next generation Multi-Processor Systems-on-a-chip (MPSoC) silicon platforms used in multimedia mobile devices should design efficient systems for diverse execution time vs. energy consumption trade-offs for a given quality of service. By exploiting Dynamic Voltage and Frequency Scaling (DVFS) techniques we can obtain singular computational/power trades offs points and thus design energy efficient platforms. This paper presents a high level methodology to acquire an optimal set of working points for an MPEG-4 Single Profile (SP) Video encoder implementation. The flow starts from a MPEG-4 encoder described in C++ language which is translated to a SystemC hard/soft description which will be analyzed and further mapped into different platforms. Refined code is migrated to four different processor architectures: a processor research framework (CRISP-Trimaran), a soft core processor with specific functional units implemented on an Altera FPGA, an ASIC and a classic DSP.

Dynamic Voltage Scaling for Power Efficient MPEG4-SP Implementation

Traditionally, engineers design for the worst case scenario but in most cases the maximum performance is not required so that there is an important waste of energy consumption. Developers should design systems for different power consumption versus execution time tradeoffs. By exploiting Dynamic Voltage and Frequency Scaling (DVFS) techniques we can reach different computational/power trades offs points and thus design power efficient platforms. In this paper, we present a high level methodology to get an optimal set of working points for an MPEG-4 Single Profile (SP) Video encoder implementation. The flow starts from a C++ description of a MPEG-4 encoder which is translated to a SystemC implementation which will be analyzed and further mapped into different platforms. Refined code is migrated to four different processor architectures: a processor research framework (trimaran), a soft core processor with specific functional units implemented on an Altera FPGA, an ASIC and a typical DSP.