Zoran Salcic

A Synchronous Approach for IEC 61499 Function Block Implementation

IEC 61499 has been endorsed as the standard for modeling and implementing distributed industrial process measurement and control systems. The standard prescribes the use of function blocks for designing systems in a component-oriented approach. The execution model of a basic function block and the manner for event/data connections between blocks are described therein. Unfortunately, the standard does not provide exhaustive specifications for function block execution. Consequently, multiple standard-compliant implementations exhibiting different behaviors are possible. This not only defeats the purpose of having a standard but also makes verification of function block systems difficult. To overcome this, we propose synchronous semantics for function blocks and show its feasibility by translating function blocks into a subset of Esterel, a well-known synchronous language. The proposed semantics avoids causal cycles common in Esterel and is proved to be reactive and deterministic under any composition. Moreover, verification techniques developed for synchronous systems can now be applied to function blocks.

A Comparison of Accuracy Using a GPS and a Low-Cost DGPS

After the cancellation of selective availability in May 2000, the accuracy of plain uncorrected global positioning systems (GPSs) is significantly increased. Currently, the main cause of error in plain GPS receivers is imperfect compensation of the ionospheric error. Tests performed in New Zealand show that even a simple code range differential GPS (DGPS) provides significant improvement in accuracy over a plain GPS and can be implemented using low-cost off-the-shelf equipment. A simple statistical model of positioning error estimation is developed and applied on data obtained by measurements in order to verify the findings. The method, which needs only position information without satellite constellation, provides sufficient accuracy when simultaneously gathered plain GPS and DGPS data are compared

Hardware–Software Codesign of Automatic Speech Recognition System for Embedded Real-Time Applications

We present a hardware-software coprocessing speech recognizer for real-time embedded applications. The system consists of a standard microprocessor and a hardware accelerator for Gaussian mixture model (GMM) emission probability calculation implemented on a field-programmable gate array. The GMM accelerator is optimized for timing performance by exploiting data parallelism. In order to avoid large memory requirement, the accelerator adopts a double buffering scheme for accessing the acoustic parameters with no assumption made on the access pattern of these parameters. Experiments on widely used benchmark data show that the real-time factor of the proposed system is 0.62, which is about three times faster than the pure software-based baseline system, while the word accuracy rate is preserved at 93.33%. As a part of the recognizer, a new adaptive beam-pruning algorithm is also proposed and implemented, which further reduces the average real-time factor to 0.54 with the word accuracy rate of 93.16%. The proposed speech recognizer is suitable for integration in various types of voice (speech)-controlled applications.

Fast track article: Ambient intelligence platform using multi-agent system and mobile ubiquitous hardware

In this paper, a novel ambient intelligence (AmI) platform is proposed to facilitate fast integration of different control algorithms, device networks and user interfaces. This platform defines the overall hardware/software architecture and communication standards. It consists of four layers, namely the ubiquitous environment, middleware, multi-agent system and application layer. The multi-agent system is implemented using Java Agent DEvelopment (JADE) framework and allows users to incorporate multiple control algorithms as agents for managing different tasks. The Universal Plug and Play (UPnP) device discovery protocol is used as a middleware, which isolates the multi-agent system and physical ubiquitous environment while providing a standard communication channel between the two. An XML content language has been designed to provide standard communication between various user interfaces and the multi-agent system. A mobile ubiquitous setup box is designed to allow fast construction of ubiquitous environments in any physical space. The real time performance analysis shows the potential of the proposed AmI platform to be used in real-life AmI applications. A case study has also been carried out to demonstrate the possibility of integrating multiple control algorithms in the multi-agent system and achieving a significant improvement on the overall offline learning performance.

A floating-point FPGA-based self-tuning regulator

Recursive-least-square (RLS) algorithm is widely used in many areas with real-time implementation using digital signal processors. In this paper, the authors present a pure hardware implementation of a self-tuning regulator (STR) that uses a real-time RLS algorithm as the parameter estimator. The STR contains a controller design circuit and a controller circuit. Due to RLS computation-precision and dynamic-range requirements, the hardware implementation uses a floating-point format. The floating-point processing elements presented in this paper use parameterized design, where the number of exponents and mantissa bits can be changed as the data range and the accuracy of a specific application require. The strategies for overcoming the covariance matrix asymmetrical problem during the hardware computation and the covariance matrix resetting is introduced when the system is poorly exciting are presented. The design was verified with real-time experiments using a new testbed. The experiment results are presented.

Mobile Station Positioning Using GSM Cellular Phone and Artificial Neural Networks

In this paper, we describe a novelapproach to mobile station positioning using a GSMmobile phone. The approach is based on the use of aninherent feature of the GSM cellular system (themobile phone continuously measures radio signalstrengths from a number of the nearest base stations(antennas)) and on the use of this information to estimatethe phones location. The current values of the signalstrengths are processed by a trained artificial neuralnetwork executed at the computer attached to themobile phone to estimate the position of the mobilestation in real time. The neural network configurationis obtained by using a genetic algorithm that searchesthe space of specific neural network types anddetermines which one provides the best locationestimation results. Two general methods are explored:the first is based on using a neural network forclassification and the second uses functionapproximation. The experimental results are reportedand discussed.

Now That's Smart!

This article describes the features and development of intelligent machines and concentrates on their information processing infrastructure. IEC 61499 function blocks have been used in these experiments as the driving vehicle to achieve important features of the intelligent machines such as reconfigurability. Information infrastructure of intelligent machines is based on the IEC 61499 architecture . The function block architecture of IEC 61499 provides a new degree of flexibility in managing embedded control and information processing systems through the lifetime of industrial automation products. The requirements of flexible manufacturing and material handling systems, such as rapid integration and reconfiguration, as well as the growing information intensity of the production environments imply that manufacturing equipment is becoming more autonomous and intelligent.

High-performance FPGA-based implementation of Kalman filter

Abstract An FPGA-based fully hardware Kalman filter has been designed and presented and a reconfigurable Kalman filter-based coprocessor in FPGAs has been proposed. High-speed arithmetic function implementations and pipelining have been used and a substantial improvement in performance has been gained. The cycle time (one iteration) for computing Kalman filter is reduced from 1.8274 μs in our previous design to 0.4013 μs. The performance gained in our approach includes two to four orders of magnitude higher speed than other implementations. The high-speed, recongifuration and easy-to-develop characteristics of the FPGA-based Kalman filter will largely broaden the real-time application area of Kalman filter.

A Multi-Mode Dead Reckoning System for Pedestrian Tracking Using Smartphones

This paper proposes an approach for pedestrian tracking using dead reckoning enhanced with a mode detection using a standard smartphone. The mode represents a specific state of carrying device, and it is automatically detected while a person is walking. This paper presents a new approach, which extends and enhances previous methods by identifying in real-time three typical modes of carrying the device and using the identified mode to enhance tracking accuracy. The way of carrying the device in all modes is unconstrained to offer reliable person-independent tracking. Based on the identification of modes, a lightweight step-based tracking algorithm is developed with a novel step length estimation model. The tracking system is implemented on a commercial off-the-shelf smartphone equipped with a built-in inertial measurement unit with 3-D accelerometer and gyroscope. It achieves real-time tracking and localization performance with an average position accuracy of 98.91%.

The SystemJ approach to system-level design

In this paper, we propose a new system-level design language, called SystemJ. It extends Java with synchronous reactive features present in Esterel and asynchronous constructs suitable for modelling globally asynchronous locally synchronous systems. The strength of SystemJ comes from its ability to offer the data processing and encapsulation elegance of Java, Esterel-like reactivity and synchrony, and the asynchronous de-coupling of CSP all within the Java framework. Using standard Java environments, for specification and modelling, or specialised reactive embedded processors, for high performance implementation, the SystemJ design flow is extremely versatile. With the increasing attention that Java gets in embedded systems, SystemJ comes to address data and control, software and hardware, modelling and implementation in a unified manner