Next-generation multiprocessor systems point to the integration of a large number of cores (e.g., processing and memory) where electrical networks-on-chip (eNoCs) can improve the communication performance. As the number of integrated cores increases, metallic interconnect in eNoCs becomes a bottleneck, leading to communication performance degradation and increased power consumption. Optical interconnection networks (OINs) have emerged to outperform the communication infrastructure in multiprocessor systems. Nevertheless, OINs’ full capability is curbed by high latency electrical controllers required to orchestrate and (re)configure the underlying photonic components, realizing a path between sending and receiving cores. Control techniques impose a high latency to perform the network routing, limiting the full utilization of OINs. In this paper, we design a novel low-latency Hybrid Controller (HyCo) that employs acceleration techniques to reduce its execution time. HyCo is developed based on integrating centralized and distributed control techniques as well as by using pre-calculated network routes and a Bloom filter, all of which result in a considerable reduction in HyCo’s latency. Simulation and prototyping results for networks up to 64×64 indicate a latency smaller than 50 ns, in the worst-case scenario.

Abstract Edge computing paradigm enables moving Internet of Things (IoT) applications from the Cloud to the edge of the network. Modern software engineering approaches are adhering to microservices to enable the deployment of such applications on edge devices. Microservices consist of the disaggregation of an application into smaller pieces that operate independently. Recent works have explored microservices packaged into containers and advocate that containers result in a reduced footprint and avoid the unwanted overhead caused by traditional virtualization. However, containers cannot be used in many deeply embedded systems (DES) due to an underlying operating system's (OSs) requirement. DES are edge devices with minimal resources regarding storage, memory, and processing power. Thus, they cannot afford large and sophisticated OSs. This article presents the Hellfire hypervisor, a lightweight virtualization implementation that enables separation and improves security in IoT applications on DES. Our proposal simplifies the traditional hypervisor approach and reaches devices where the existing techniques fail. The results show that the proposed model has a small footprint of 23 KB while keeping a low average virtualization overhead of 0.62% for multiple virtual machines execution.

Silicon photonic interconnects (SPIs) have emerged as a promising solution to outperform the communication infrastructure in multiprocessor systems-on-chip (MPSoCs). Routing a message from one node to another in an MPSoC integrating SPIs, several photonic components (e.g., switching elements) need to be configured to realize an optical path between sending and receiving nodes. Such configurations are performed in an electronic controller, which, if not fast, imposes high latency in SPIs, constraining the application of SPIs in MPSoCs. Realizing a full exploitation of SPIs, this paper presents a look-up-table-based centralized controller (LUCC). We indicate that LUCC has the lowest latency among the state-of-the-art controllers for SPIs while it can be applied to different SPI architectures. Employing acceleration techniques based on off-line routings, we report (simulation and prototyping) a worst-case control latency smaller than 5 ns. Moreover, LUCC is experimentally integrated with a photonic switch in the lab, where we show contention resolution in one clock cycle.

The adoption of the Internet of Things (IoT) demands advances to cope with the large heterogeneity of IoT entities (i.e., systems, applications, and devices). Context information is an essential characteristic of these entities, which can store relevant details about their environments and related events. However, with the integration of different IoT vertical domains, providing isolated context is no longer enough. Sharing the context information is mandatory to have interoperability. Edge computing emerges as a promising approach to help in filling the context sharing gap by minimizing information overhead and reducing network latency. In this sense, this paper defines an Edge-centric Context Sharing Architecture able to make context sharing based on edge-to-fog approach. We also discuss the requirements for context sharing and the related work in the area to make clear the novelty of the architecture.

The Internet of Things (IoT) will connect billions of devices deployed around the world in a near future by embedding mobile network and processing power capabilities into a wide range of physical computing devices used in everyday life of many people. Recent studies concerning IoT have addressed not only the interoperability of devices, but also the context awareness feature which makes easy to discover, understand, and store relevant information related to IoT devices. This work aims to present a Context-Aware System called CONASYS, a system able to sense the environment and to provide contextualized services to the users, meeting the users needs without specific knowledge of the environment, and improving the Quality of Experience (QoE). We present in details the architecture of CONASYS, the technical issues related to the implementation of the system, and evaluation tests.

The evolution of the Internet of Things (IoT) has brought new security requirements in terms of communication services with respect to data transmitted in mobile networks. Although IoT middleware systems have been used to cope with the most relevant requirements demanded by different IoT applications, security is a special topic that is not mature enough in this kind of technology. E-health is an example of environment that exposes sensitive data. The security challenges regarding e-health applications are concentrated mainly on issues surrounding the communication layer, specially those cases where data are transmitted over insecure networks. TLS and DTLS protocols have been chosen by most of the existing IoT systems in order to protect such communications. However, none of them was designed to be used in IoT situations. In addition, none of the existing works analyzes their suitability to the IoT regarding the usage of mobile networks, which are common in real-world scenarios of e-health. In this paper, we analyze the use of TLS and DTLS protocols in IoT middleware systems applied to the e-health environment regarding performance (i.e., response time), overhead, network latency and packet loss when operating in mobile networks. We evaluated both protocols through a specific e-health scenario. Tests revealed the usage of mobile networks increases response time and overhead of both protocols, on average, when compared to traditional networks.

During the past few years, with the fast development and proliferation of the Internet of Things (IoT), many application areas have started to exploit this new computing paradigm. The number of active computing devices has been growing at a rapid pace in IoT environments around the world. Consequently, a mechanism to deal with this different devices has become necessary. Middleware systems solutions for IoT have been developed in both research and industrial environments to supply this need. However, decision analytics remain a critical challenge. In this work we present the Decision Support IoT Framework composed of COBASEN, an IoT search engine to address the research challenge regarding the discovery and selection of IoT devices when large number of devices with overlapping and sometimes redundant functionality are available in IoT middleware systems, and DMS, a rule-based reasoner engine allowing to set up computational analytics on device data when it is still in motion, extracting valuable information from it for automated decision making. DMS uses Complex Event Processing to analyze and react over streaming data, allowing for example, to trigger an actuator when a specific error or condition appears in the stream. The main goal of this work is to highlight the importance of a decision support system for decision analytics in the IoT paradigm. We developed a system which implements DMS concepts. However, for preliminarily tests, we made a functional evaluation of both systems in terms of performance. Our initial findings suggest that the Decision Support IoT Framework provides important approaches that facilitate the development of IoT applications, and provides a new way to see how the business rules and decision-making will be made towards the Internet of Things.

Embedded virtualization has emerged as a valuable way to reduce costs, improve software quality, and decrease design time. Additionally, virtualization can enforce the overall system's security from several perspectives. One is security due to separation, where the hypervisor ensures that one domain does not compromise the execution of other domains. At the same time, the advances in the development of IoT applications opened discussions about the security flaws that were introduced by IoT devices. In a few years, billions of these devices will be connected to the cloud exchanging information. This is an opportunity for hackers to exploit their vulnerabilities, endangering applications connected to such devices. At this point, it is inevitable to consider virtualization as a possible approach for IoT security. In this paper we discuss how embedded virtualization could take place on IoT devices as a sound solution for security.

During the past few years, with the fast development and proliferation of the Internet of Things (IoT), many application areas have started to exploit this new computing paradigm. An interesting use of IoT is in the Industrial field, which has resulted in a new business concept called IIoT (Industrial Internet of Things). Another important fact is the number of active computing devices has been growing at a rapid pace in IoT environments around the world. Consequently, a mechanism to deal with this different devices has become necessary. Middleware systems solutions for IoT have been developed in both research and industrial environments to supply this need. However, discover, search, select, and interact with devices remain a critical challenge. In this paper we present COBASEN, a software framework composed of a Context Module and a Search Engine to address the research challenge regarding the discovery and interaction with IoT devices when large number of devices with overlapping and sometimes redundant functionality are available in IoT middleware systems. The search engine of the COBASEN operates based on the semantic characteristics of the devices, which is provided by the context module, and that helps users in their interactions with desired devices. The main goal of this work is to highlight the importance of a context-based search engine in the IoT paradigm and to provide a solution that addresses the proper management of search and usage in IoT middleware environments. We developed a tool that implements all COBASEN concepts. However, for preliminarily tests, we made a functional evaluation of the search engine in terms of performance for indexing and querying response time. Our initial findings suggest that COBASEN provides important approaches that facilitate the development of IIoT applications, which based on the COBASEN systems support, may perform essential roles to improve industrial processes.

In the last years a new computing paradigm called Internet of Things (IoT) has been gaining more attention. This paradigm has become popular by embedding mobile network and processing capability into a wide range of physical computing devices used in everyday life of many people. An important part that composes the IoT is the middleware, which is a system that abstracts the management of physical devices and provides services based on the information of these devices. Context-aware is an important feature of IoT middleware systems. This feature allows to discover, understand, and store relevant information related to devices and their respective events. In this sense, this work aims to present an ongoing system that has been developed to provide services of contextualized information about IoT devices in heterogeneous environments.

Multiprocessor System-on-Chip (MPSoC) can be found in almost every market branch and its design typically presents several restrictions such as chip area and energy consumption. State-of-art MPSoCs uses networks-on-chip as the primary communication infrastructure and the tendency is that NoC-based systems will still be used for a long time, thanks to a greater design flexibility and also a high communication bandwidth and parallelism. However, such systems also have certain usage restrictions, such as the location of the tasks that compose the application. Mapping and partitioning techniques seek to solve this problem or at least reduce it to a non critical point by diving tasks along the architecture but are not always completely successful. In this context, cluster-based architectures emerges as a viable alternative to MPSoCs. This type of system typically has a hybrid architecture on its constitution, using more than one communication infrastructure, thus being able to group elements by affinity and still use high-speed communication channels, such as NoCs. In this way, the presented work introduces the HC-MPSoC, an architecture for cluster-based intrachip systems, which uses buses and a NoC in a joint way, forming groups of elements independently distributed throughout the platform. The extensions made on the HellfireOS in order to execute it over the hybrid architecture are also presented. All HC-MPSoC modules as well as the HellfireOS modules and the results obtained using the platform are presented along the text.

Multiprocessed System-on-Chip (MPSoCs) have become a recurrent implementation alternative to modern embedded systems and, lately, have counted on resources previously available only on general purpose machines. In this context, it is possible to highlight that many techniques formerly adopted in general-purpose computers have been studied and adapted to the embedded reality. Thus, embedded communication infrastructures such as buses and networks-on-Chip (NoCs) are based on general-purpose solutions and are widely accepted for embedded systems. Also, embedded systems make use of Operating Systems (OS), as they provide standard interfaces to access hardware resources, including the communication facilities. However, although the underlying communication infrastructure can differ in order to improve a given metric, such as performance, power or area, it is desirable that the software layer remains the same, especially in terms of the application's and OS's code improving the overall software quality. Still, certain OS parameters can directly influence on the overall system performance. This paper presents a highly configurable Real Time OS (RTOS) that implements a communication protocol to provide a transparent communication interface for both bus- and NoC-based MPSoCs' applications.

The emergence of wireless networks has contributed to a growing number of studies and protocols regarding its performance and reliability requirements, among others. Several issues have to be considered when deploying such devices under harsh environmental conditions. These issues often force the designer to adopt decisions that are usually difficult to verify in real world settings. In order to mitigate such problems, an alternative resides in the use of simulation models for both homogeneous and heterogeneous devices. This paper describes an event-based Wireless Network Simulator (WiNeS) for devices operating in several topologies and configurations of networks. WiNeS is a Java-based framework specially built to support customized network options that offers hybrid simulation for virtual and physical nodes in the same environment. Some of WiNeS' features include the computation of maximum communication distances among devices in 2D and 3D spatial node distributions as well as pairing rules to evaluate the nodes connectivity.

The downscaling of silicon technology and the possibility of building MPSoCs, make intrachip communication a mainstream research topic. NoCs are an elegant solution to provide communication scalability and modularity. NoCs are already common in MPSoC design. Moreover, new technology challenges point to a growth in the use of non-synchronous NoCs. However, the design of asynchronous infrastructures with current EDA tools is challenging. That is due to the fact that most of these tools are oriented towards synchronous design. This work proposes and evaluates a fully asynchronous NoC router based on the Balsa language and framework. The design is validates through FPGA synthesis.

Modern embedded systems implemented through Multiprocessor System-on-Chip (MPSoCs) benefit themselves from resources that were previously available solely in generalpurpose computers. Currently, these systems are able to provide more features at the cost of an increased design complexity. In this scenario, the applications' behaviour has changed. In the past, the majority of applications showed a static behaviour throughout their entire lifetime. Applications could be divided into tasks and mapped onto processing elements at design time. Currently, the applications' dynamic nature imposes that efficient dynamic load balancing techniques with different task mapping strategies must arise, although a fair static mapping still helps increasing the system overall performance. In this paper we present a task model suitable for dynamic load balancing of real-time applications with special support for Network-on-Chip (NoC)-based MPSoCs that aims to stabilize the system load throughout its lifetime. Results show a reduction in both system stabilization time (mean of 47.62%) and deadline misses (mean of 32.28%) for several benchmarks, compared to classic approaches which employ a centralized migration manager.

RFID systems usually need to be applied where the installation cost can be very high, and thus, running a simulation in such environments would bring many benefits such as saving time and money. In this case, the simulation could be considered as a prediction method that verifies whether the configuration for the desired scenario works correctly and meets the system's requirements. This work presents a research about statistical prediction models for RFID systems' coverage in a specific scenario. In order to predict the RFID system coverage, the tag read count was measured in an indoor environment. In the chosen scenario, RFID technology is applied to smart cards. This research presents a model using Multiple Linear Regression and another approach using Artificial Neural Networks on the prediction of the read count. Results showed improvements on the prediction of area coverage, bringing advantages to RFID projects, such as less time and resources required to RFID systems deployment.

Virtualization has become a hot topic in embedded systems for both academia and industry development. Among its main advantages, we can highlight (i) software design quality; (ii) security levels of the system; (iii) software reuse, and; (iv) hardware utilization. However, it still presents constraints that have lessened the excitement towards itself, since the greater concerns are its implicit overhead and whether it is worthy or not. Thus, we detail how to adapt an existing MIPS-based architecture aiming to support the virtualization principles. In this paper we present detailed information about the architecture implementation and results demonstrating its correctness and efficiency.

SUMMARY Traditionally, virtualization has been adopted by enterprise industry to make better use of the general purpose processors (single and multicore) besides improving the utilization of existing computational resources, especially in data centers. Until recently, its use in embedded systems (ESs) seemed to be a distant, unnecessary, and unfeasible reality. However, with the rise of each more powerful multiprocessed ESs, typically implemented as multiprocessor system‐on‐chip, virtualization has become a very promising technique to achieve and improve functionalities in future multiprocessor system‐on‐chips. One of the main advantages of virtualizing ESs is to improve the software design quality because legacy software can be reused along with newer applications. Also, we have the classic use cases, such as allowing several operating systems (OSs) to work in the same physical resource, simultaneously. Still, we can provide more secure ESs by splitting the system into user application OS and security certified OS, for instance. Moreover, depending on the way that embedded virtualization is employed, it may be even possible to reduce manufacturing costs and energy consumption levels. However, it is well understood that although ESs deal with increasingly more powerful solutions, they are still far more restricted than general purpose computers, especially in terms of area, memory size, and power consumption. In this article, we provide an extensive analysis of what is being currently offered as embedded virtualization solution, the pros and cons, besides presenting an innovative proposal regarding virtualization for restricted embedded architectures and its possible advantages. Copyright © 2012 John Wiley & Sons, Ltd.

Public transportation companies aim to incorporate quality and modern technologies on their services hoping to achieve the optimization of the employed material resources. Although the available resources are controlled, there is a lack of reliability in the process involved, mainly due human interactions which are subject to failures. This work presents an RFID system for fuel supply control of vehicles fleets. The system is based on a modular and adaptative RFID middleware (CloudRFID) which surveys as a foundation to the development of RFID applications. The outcome of this work demonstrates the advantages of the integration of RFID systems with process and business functionalities involving resources control and automation.

The rising use of RFID has been stimulating the world market through strong financial investments heading for the adoption of RFID as a standard identification technology. Such initiative has been fomenting the necessity of an infrastructure able to deal with the restrictions and limitations imposed by business areas and RFID environments. This work presents a modular and adaptive framework architecture that implements the EPC Network specifications and that aims at facilitating the RFID applications development. The framework is composed by modules that provide communication interfaces for different applications and reader devices and also a set of functions for data processing and information services. For the work validation, the framework was integrated in a real system for fuel supply control of vehicle fleets and the results demonstrated its efficiency in the integration of RFID systems.

Embedded Systems-

Efficient energy consumption became an important requirement and constraint to be considered in many systems implementations, mainly to the embedded ones. Accurate and efficient power estimation during the design phase is required, in order to meet the power specifications without a costly redesign. High abstraction levels descriptions enable fast energy consumption estimations, but hardly enable accurate estimations. It normally requires evaluations at low abstraction levels, such as electric ones. On the other hand, low abstraction levels require too much design effort and design time. In this sense, this work presents an approach for energy consumption estimation for systems written in synthesizable VHDLs. A VHDL cell library is the base of the methodology, which is characterized with some relevant energy consumption information according to foundry parameters. The use of this approach leads to high-quality energy consumption estimations and design time saving.

This paper describes the implementation of a passive RFID tag targeting low power implementation, which works on 915 MHz UHF frequency. The proposed architecture allows customizing the command sets implemented inside its digital block, according to the target application needs, saving area and reducing power consumption. A flexible design flow is proposed for the customization, verification and synthesis of the digital block, targeting low power requirements.

Scheduling decision for real-time embedded software applications has a great impact on system performance and, therefore, is an important issue in RTOS design. Moreover, it is highly desirable to have the system designer able to evaluate and select the right scheduling policy at high abstraction levels, in order to allow faster exploration of the design space. In this paper, we address this problem by introducing an abstract RTOS model, as well as a new approach to refine an unscheduled high-level model to a high-level model with RTOS scheduling. This approach is based on SystemC language and enables the system designer to quickly evaluate different dynamic scheduling policies and make the optimal choice in early design stages. Furthermore, we present a case of study where our model is used to simulate and analyze a telecom system.

Complex applications implemented as systems on chip (SoC) demand extensive use of system level modeling and validation. Their implementation gathers a large number of complex IP cores and advanced interconnection schemes, such as hierarchical bus architectures or networks on chip (NoC). Modeling applications involves capturing its computation and communication characteristics. Previously proposed communication weighted models (CWM) consider only the application communication aspects. This work proposes a communication dependence and computation model (CDCM) that can simultaneously consider both aspects of an application. It presents a solution to the problem of mapping applications on regular NoC while considering execution time and energy consumption. The use of CDCM is shown to provide estimated average reductions of 40% in execution time, and 20% in energy consumption, for current technologies.

The complexity of modern embedded systems requires the cooperation of several teams belonging to different cultures and using different languages as well as the reuse of software, hardware and communication IP modules at the early design steps. The key issue for the design of such systems is the overall system validation and the synthesis of the communication between the different subsystems. In this paper we focus on the problem of multi-level communication synthesis and show the results of the application of this methodology on an example. Designers get feedback at all design steps via the cosimulation engine that permits fast evaluation.