Real-time Systems

Bluehive — A Field-Programable Custom Computing Machine for Extreme-Scale Real-Time Neural Network Simulation

by Paul Fox

Presented at FCCM 2012

Bluehive is a custom 64-FPGA machine targeted at scientific simulations with demanding communication re- quirements.... more Bluehive is a custom 64-FPGA machine targeted at scientific simulations with demanding communication re- quirements. Bluehive is designed to be extensible with a recon- figurable communication topology suited to algorithms with demanding high-bandwidth and low-latency communication, something which is unattainable with commodity GPGPUs and CPUs. We demonstrate that a spiking neuron algorithm can be efficiently mapped to Bluehive using Bluespec SystemVerilog by taking a communication-centric approach. This contrasts with many FPGA-based neural systems which are very focused on parallel computation, resulting in inefficient use of FPGA resources. Our design allows 64k neurons with 64M synapses per FPGA and is scalable to a large number of FPGAs.

Real-Time Virtual Metrology and Control of Plasma Electron Density in an Industrial Plasma Etch Chamber

by Shane Lynn

18th IFAC World Congress, Aug. 2011.
co-Authored with Niall MacGearailt and John V. Ringwood

Plasma etching is a semiconductor manufacturing process during which material is removed from the surface of silicon... more Plasma etching is a semiconductor manufacturing process during which material is removed from the surface of silicon wafers using gases in plasma form. A host of chemical and
electrical complexities make the etch process notoriously difficult to model and troublesome to control. This work demonstrates the use of a real-time model predictive control scheme to maintain a consistent plasma electron density in the presence of disturbances to the ground path of the chamber. The electron density is estimated in real time using a virtual metrology model based on plasma impedance measurements. Recursive least squares is used to update the controller model parameters in real time to achieve satisfactory control of electron density over a wide operating space.

Design of Adaptive Security Mechanisms for Real-Time Embedded Systems

by Mehrdad Saadatmand

The 4th International Symposium on Engineering Secure Software and Systems

Continuous data recording on fast real-time systems

by Gianmaria De Tommasi

published in 'Fusion Engineering and Design', 2010

The PCU-Project [1] launched for the enhancement of the vertical stabilisation system at JET required the design of a... more The PCU-Project [1] launched for the enhancement of the vertical stabilisation system at JET required the design of a new real-time control system with the challenging specifications of  and a cycle time of 50 s. The RTAI based architecture running on an x86 multi-core processor technology demonstrated to be the best platform for meeting the high requirements. Moreover, on this architecture thanks to the smart allocation of the interrupts it was possible to demonstrate simultaneous data streaming at 50 MBs on Ethernet while handling a real-time 100 kHz interrupt source with a maximum jitter of just 3 s.

Because of the memory limitation imposed by 32 bit version Linux running in kernel mode, the RTAI-based new controller allows a maximum practical data storage of 800 MB per pulse. While this amount of data can be accepted for JET normal operation it posed some limitations in the debugging and commissioning of the system. In order to increase the capability of the data acquisition of the system we have designed a mechanism that allows continuous full bandwidth (56 MB/s) data streaming from the real-time task (running in kernel mode) to either a data collector (running in user mode) or an external data acquisition server. The exploited architecture involves a peer to peer mechanisms where the sender running in RTAI kernel mode broadcasts large chunks of data using UDP packets, implemented using the ‘fcomm’ RTAI extension [2], to a receiver that will store the data. The paper will present the results of the initial RTAI operating system tests, the design of the streaming architecture and the first experimental results.

Performance Comparison of EPICS IOC and MARTe in a Hard Real-Time Control Application

by Gianmaria De Tommasi

published in 'IEEE Transactions on Nuclear Science', 2011

EPICS is used worldwide mostly for controlling accelerators and large experimental physics facilities. Although EPICS... more EPICS is used worldwide mostly for controlling accelerators and large experimental physics facilities. Although EPICS is well fit for the design and development of automation systems, which are typically VME or PLC-based systems, and for soft real-time systems, it may present several drawbacks when used to develop hard real-time systems/applications especially when general purpose operating systems as plain Linux are chosen. This is in particular true in fusion research devices typically employing several hard real-time systems, such as the magnetic control systems, that may require strict determinism, and high performance in terms of jitter and latency. Serious deterioration of important plasma parameters may happen otherwise, possibly leading to an abrupt termination of the plasma discharge. The MARTe framework has been recently developed to fulfill the demanding requirements for such real-time systems that are alike to run on general purpose operating systems, possibly integrated with the low-latency real-time preemption patches. MARTe has been adopted to develop a number of real-time systems in different Tokamaks. In this paper, we first summarize differences and similarities between EPICS IOC and MARTe. Then we report on a set of performance measurements executed on an x86 64 bit multicore machine running Linux with an IO control algorithm implemented in an EPICS IOC and in MARTe.

A Survey of Recent MARTe Based Systems

by Gianmaria De Tommasi

published in 'IEEE Transactions on Nuclear Science', 2011

The Multithreaded Application Real-Time executor (MARTe) is a data driven framework environment for the development... more The Multithreaded Application Real-Time executor (MARTe) is a data driven framework environment for the development and deployment of real-time control algorithms. The main ideas which led to the present version of the framework were to standardize the development of real-time control systems, while providing a set of strictly bounded standard interfaces to the outside world and also accommodating a collection of facilities which promote the speed and ease of development, commissioning and deployment of such systems. At the core of every MARTe based application, is a set of independent inter-communicating software blocks, named Generic Application Modules (GAM), orchestrated by a real-time scheduler. The platform independence of its core library provides MARTe the necessary robustness and flexibility for conveniently testing applications in different environments including non-real-time operating systems. MARTe is already being used in several machines, each with its own peculiarities regarding hardware interfacing, supervisory control configuration, operating system and target control application. This paper presents and compares the most recent results of systems using MARTe: the JET Vertical Stabilization system, which uses the Real Time Application Interface (RTAI) operating system on Intel multi-core processors; the COMPASS plasma control system, driven by Linux RT also on Intel multi-core processors; ISTTOK real-time tomography equilibrium reconstruction which shares the same support configuration of COMPASS; JET error field correction coils based on VME, PowerPC and VxWorks; FTU LH reflected power system running on VME, Intel with RTAI.

Real-time Systems in Tokamak Devices. A Case Study: the JET Tokamak

by Gianmaria De Tommasi

published in 'IEEE Transactions on Nuclear Science', 2011

The achievement of the required performances during the operation of large fusion experimental reactors, is strictly... more The achievement of the required performances during the operation of large fusion experimental reactors, is strictly related to the flexibility and reliability of the real-time infrastructures. It turns out that, in tokamak reactors, the real-time infrastructure has to be designed so as to meet a number of common requirements. An overview of the real-time infrastructure currently adopted at the JET tokamak is given in this paper, focusing the attention on the solutions that have been developed for addressing these common requirements. Furthermore, three real-time systems recently deployed at JET are described as example.

MARTe: a Multi-Platform Real-Time Framework

by Gianmaria De Tommasi

published in 'IEEE Transactions on Nuclear Science', 2010

Development of real-time applications is usually associated with nonportable code targeted at specific real-time... more Development of real-time applications is usually associated with nonportable code targeted at specific real-time operating systems. The boundary between hardware drivers, system services, and user code is commonly not well defined, making the development in the target host significantly difficult. The Multithreaded Application Real-Time executor (MARTe) is a framework built over a multiplatform library that allows the execution of the same code in different operating systems. The framework provides the high-level interfaces with hardware, external configuration programs, and user interfaces, assuring at the same time hard real-time performances. End-users of the framework are required to define and implement algorithms inside a well-defined block of software, named Generic Application Module (GAM), that is executed by the real-time scheduler. Each GAM is reconfigurable with a set of predefined configuration meta-parameters and interchanges information using a set of data pipes that are provided as inputs and required as output. Using these connections, different GAMs can be chained either in series or parallel. GAMs can be developed and debugged in a non-real-time system and, only once the robustness of the code and correctness of the algorithm are verified, deployed to the real-time system. The software also supplies a large set of utilities that greatly ease the interaction and debugging of a running system. Among the most useful are a highly efficient real-time logger, HTTP introspection of real-time objects, and HTTP remote configuration. MARTe is currently being used to successfully drive the plasma vertical stabilization controller on the largest magnetic confinement fusion device in the world, with a control loop cycle of 50 ?s and a jitter under 1 ?s. In this particular project, MARTe is used with the Real-Time Application Interface (RTAI)/Linux operating system exploiting the new ?86 multicore processors technology.

A flexible software for real-time control in nuclear fusion experiments

by Gianmaria De Tommasi

published in 'Control Engineering Practice', 2006

JETRT is a software framework particularly suited for implementation of both real-time control and data acquisition... more JETRT is a software framework particularly suited for implementation of both real-time control and data acquisition systems. It is especially designed to work in a complex experimental environment such as the JET nuclear fusion facility. This new architecture maximizes the software reusability. The project-specific algorithm is compiled into a separate software component, in order to achieve a separation from the plant interface code. JETRT provides a set of tools to perform most of the validation phase on a Windows running desktop PC. Thanks to these design choices, both the development costs and the commissioning time have been reduced and even non-specialist programmers can easily contribute to the deployment of a new real-time system.

A Real-Time Quality Assurance Tool for the Cyprus Construction Industry

by Vassos Vassiliou

APPLYING THE COMMONKADS-RT METHODOLOGY TO ANALYSE REAL-TIME ARTIFICIAL INTELLIGENCE SYSTEMS

by Monica Henao-Calad

http://www.lsi.us.es/iberamia2002/confman/SUBMISSIONS/222-icvsicibon.pdf

Advances in Real-Time Artificial Intelligence facilitate the creation of large AI applications. In order to more Advances in Real-Time Artificial Intelligence facilitate the creation of large AI applications. In order to
develop such applications, a methodology that encompasses development techniques, tools and processes
is needed. There are several important lines of research in RTAIS, such as architectures, languages,
methods and methodologies. All of them provide the necessary information and knowledge to build
computers systems to solve real-world problems.
This paper describes CommonKADS-RT, a methodology to analyse and design Real Time Intelligent
Systems. It is based on CommonKADS with the addition of elements necessary to model real-time
restrictions. We also present an application of this approach to examine maritime operation problems. On
this paper we describe the analysis phase.

Real-Time Modeling for Direct Load Control in Cyber-Physical Power Systems

by Marco Della Vedova

Co-authored with Tullio Facchinetti, pre-published in IEEE Transactions on Industrial Informatics, 2011

This paper presents an innovative approach to use real-time scheduling techniques for the automation of electric loads... more This paper presents an innovative approach to use real-time scheduling techniques for the automation of electric loads in Cyber-Physical Power Systems. The goal is to balance the electric power usage to achieve an optimized upper bound on the power peak load, while guaranteeing specific constraints on the physical process controlled by the electric loads. Timing parameters derived from the scheduling discipline of real-time computing systems are used to model electric devices. Real-time scheduling algorithms can be exploited to achieve the upper bound by predictably and timely switching on/off the devices composing the electrical system. The paper shows the relevance of electric load balancing in power systems to motivate the use of real-time techniques to achieve predictability of electric loads scheduling. Real-Time Physical Systems (RTPS) are introduced as a novel modeling methodology of a physical system based on real-time parameters. They enable the use of traditional realtime system models and scheduling algorithms, with adequate adaptations, to manage loads activation/deactivation. The model of the physical process considered in this work is characterized by uncertainties that are compensated by a suitable feedback control policy, based on the dynamic adaptation of real-time parameter values. A number of relevant relationships between real-time and physical parameters are derived.

Safe Programming Languages for ABB Automation System 800xA

by Markus Borg

The old master thesis should be here to make me feel... uncomfortable.

More than 90 % of all computers are embedded in different types of systems, for example mobile phones and industrial... more More than 90 % of all computers are embedded in different types of systems, for example mobile phones and industrial robots. Some of these systems are real-time systems; they have to produce their output within certain time constraints. They can also be safety critical; if something goes wrong, there is a risk that a great deal of damage is caused. Industrial Extended Automation System 800xA, developed by ABB, is a realtime control system intended for industrial use within a wide variety of applications where a certain focus on safety is required, for example power plants and oil platforms. The software is currently written in C and C++, languages that are not optimal from a safety point of view. In this master’s thesis, it is investigated whether there are any plausible alternatives to using C/C++ for safety critical real-time systems. A number of requirements that programming languages used in this area have to fulfill are stated and it is evaluated if some candidate languages fulfill these requirements. The candidate languages, Java and Ada, are compared to C and C++. It is determined that the Java-to-C compiler LJRT (Lund Java-based Real Time) is a suitable alternative. The practical part of this thesis is concerned with the introduction of Java in 800xA. A module of the system is ported to Java and executed together with the original C/C++ solution. The functionality of the system is tested using a formal test suite and the performance and memory footprint of our solution is measured. The results show that it is possible to gradually introduce Java in 800xA using LJRT, which is the main contribution of this thesis.

Syndromic surveillance use to detect the early effects of heat-waves: an analysis of NHS Direct data in England

by Giovanni Leonardi

Safety Applications of Automatic Vehicle Identification and Real-Time Weather Data on Freeways

by Mohamed Ahmed

Mohamed Ahmed, Rongjie Yu, and Mohamed Abdel-Aty
Presented at the 18th World Congress on Intelligent Transport Systems, 2011.

While the most common application of the Automatic Vehicle Identification is electronic toll collection and travel... more While the most common application of the Automatic Vehicle Identification is electronic toll collection and travel time estimation, there is a promising traffic safety application in the context of Advanced Travel Management. This paper examines the usefulness of traffic data collected from Automatic Vehicle Identification systems and weather data in real-time crash analysis. Matched case-control was used to link real-time space mean speed collected by AVI and real-time weather data and crash likelihood. The 10-minute average speed five minutes before the crash occurrence and the 1-hour visibility both before the crash time were found to be the most significant factors that affect the crash likelihood.

A Time-Triggered Object Tracking Subsystem for Advanced Driver Assistance Systems

by Wilfried Elmenreich

Multi-sensor object tracking is an important feature for advanced driver assistance systems in future automobiles.... more Multi-sensor object tracking is an important feature for advanced driver assistance systems in future automobiles. Most state-of-the-art systems cannot guarantee deterministic processing of the sensor values due to unsynchronized sensing and processing units. To overcome this shortcoming we propose a paradigm shift towards a time-triggered system architecture providing a deterministic bus system, synchronized nodes, and a global time-base. The paradigm shift is supported by results of a simulation of different synchronization and scheduling approaches which suggest that although non-time-triggered approaches perform well in scenarios with low process noise, the time-triggered model becomes advantageous in potentially dangerous scenarios with high dynamics. In order to validate the results of the simulation for real life scenarios, we analyzed test drives derived from a testbed featuring a Volkswagen Touran being equipped with a laser scanner, a stereo camera system, a FlexRay communication system, an object tracking subsystem and a differential GPS system as reference.

Prediction of end-to-end deadline missing in distributed threads systems

by Carlos Montez

Dealing with overloading in Tasks Scheduling

by Carlos Montez

Time Interval Semantics and Implementation of a Real-Time Programming Language

by Jonathan Bowen

Real-time platooning of mobile robots: design and implementation

by Marco Della Vedova

The platooning is a coordination technique for teams of mobile units that aims at letting each unit to move closely to... more The platooning is a coordination technique for teams of mobile units that aims at letting each unit to move closely to its receding neighbour, thus forming the so-called platoon.
This paper describes the design and implementation of a distributed robotics application where a team of autonomous mobile robots are coordinated to move as a platoon. The focus will be on the on-board real-time computing that allows a predictable robot's behavior. Experimental results are shown to assess the performance of the proposed platform.