Th. Laopoulos

Instruction-level power consumption estimation embedded processors low-power applications

A power consumption measurement framework for embedded processing systems is presented in this work. Given an assembly or machine level program as input to this setup, the energy consumption of the specific program in the specific processing systems may be estimated. The instruction level power models are derived based on the power supply current measurement technique. The instantaneous variations of the power supply current provide the appropriate information for the accurate estimation of the power consumption at different operating situations of the processor (core) and of the overall processing system as well (consumption of peripheral units). The proposed instantaneous current measuring approach, along with the execution of special test programs for analysis of inter-instruction effects provides a clear insight into the power behavior of embedded processing systems.

Sensor errors prediction using neural networks

The features of neural networks used for increasing the accuracy of physical quantity measurement are considered by prediction of sensor drift. The technique of data volume increasing for predicting neural network training is offered at the expense of various data types replacement for neural network training and at the expense of the separate approximating neural network use.

Model reference adaptive control for an ionic polymer metal composite in underwater applications

Ionic polymer metal composite (IPMC) materials are in an early stage of development. Their response as actuators is still very unpredictable. Their dynamic response is still subjected to several critical parameters that vary with time, thus extracting an accurate and repeatable model is very difficult. This paper presents the design and implementation of an adaptive efficient position control system for an IPMC actuator working in underwater conditions. The control system is an model reference adaptive control (MRAC) based on a reference model and an adaptation that controls a 1 cm × 0.5 cm length IPMC strip based on a Nafion 117 Na+ membrane. As the reference model a second-order empirical model of the plant is used. The control system is first simulated and then experimentally implemented within the LabVIEW framework.

Design and applications of an easily integrable CMOS operational floating amplifier for the megahertz range

The design and major applications of a general purpose current mode building block are presented in this paper. This circuit is basically a high gain transconductance scheme with differential current output terminals previously termed operational floating amplifier (OFA). The novel structure proposed here is shown to implement a very flexible and high performance amplifier which can be used in almost all applications employing conveyors, current feedback amplifiers or even conventional operational amplifiers with improved performance characteristics. This presentation is also supported by experimental measurements on a prototype circuit realized in CMOS technology.

Aspects of Traditional versus Virtual Laboratory for Education in Instrumentation and Measurement

Nowadays the multimedia tools have an important role in both the management of the lectures and the organization of the course program on instrumentation and measurement. In this new scenario, the virtual laboratory (VL) represents the environment in which the learning activities are performed. Starting from this observation, in the paper an overview of the state of the art of the VL-based education on instrumentation and measurement is given. The fundamental aspects concerning both the software and the hardware to design the VL are examined. Attention it is also devoted to innovative requirements and interesting open questions arising from the large diffusion of the VLs

THE INTERMITTENCY ROUTE TO CHAOS OF AN ELECTRONIC DIGITAL OSCILLATOR

An electronic oscillator producing digital signals, formed by a second-order, nonlinear, nonautonomous, closed loop topology that is based on two integrators and nonlinear elements (a comparator and a XOR gate), was experimentally investigated. For a certain frequency and amplitude range of the periodic driving signal, the intermittency route to chaos was observed and studied.

Error compensation in an intelligent sensing instrumentation system

Methods of improving the measurement accuracy by estimation and correction of the maximum error components, are analyzed. The functional structure of the measurement channel in an intelligent sensing instrumentation system is described along with the procedures of component error correction. An experimental setup, implementing such methods in a multi-processing neural network configuration, is presented.

Reducing power consumption in pseudo-ZigBee sensor networks

This paper presents a new method for power minimization in wireless sensor networks using the ZigBee protocol. A modification of the standard protocol is proposed for use to any low bit-rate data communications application resulting in a ZigBee-like network with considerably reduced power consumption. Time scheduling is proposed to switch on and off the power of the transmitter/receiver circuit, minimizing the power consumed in router devices. Thus the attractive capability of ZigBee networks to reduce the consumption at end-devices is extended to the coordinator and the routers. A small 3-nodes wireless network using the proposed method was built and studied experimentally and the results presented in this paper show a significant reduction to consumption, reaching up 85% compared to standard ZigBee configurations.

High performance frequency-to-voltage converter

ABSTRACT An analogue frequency-to-voltage converter, suitable for low and variable-frequency applications is presented. Circuit advantages include nominally zero output ripple, fast dynamic response, good accuracy and linearity in a wide frequency range.

A simple analog division scheme

A technique for analog division of two voltage signals that offers high accuracy (0.5%) and relatively good response, especially when the numerator value is nearly constant, is presented. The proposed method is based on the relation of a signals frequency to its period. The basic idea is to convert input voltage to frequency (through a voltage-controlled oscillator (VCO)) and then produce an output voltage proportional to the period of this signal. The circuit implementing this method is easy to build and may be used in many instrumentation and control applications where the reciprocal of a voltage is needed. Supporting experimental results and performance measurements are also given. >