Search results for "Detection"

Time-of-flight - Energy spectrometer for elemental depth profiling - Jyväskylä design

2014

Abstract A new time-of-flight elastic recoil detection spectrometer has been built, and initially the main effort was focused in getting good timing resolution and high detection efficiency for light elements. With the ready system, a 154 ps timing resolution was recorded for scattered 4.8 MeV 4 He 2+ ions. The hydrogen detection efficiency was from 80% to 20% for energies from 100 keV to 1 MeV, respectively, and this was achieved by having an additional atomic layer deposited Al 2 O 3 coating on the first timing detector’s carbon foil. The data acquisition system utilizes an FPGA-card to time-stamp every time-of-flight and energy event with 25 ns resolution. The different origins of the ba…

Improvement of time-of-flight spectrometer for elastic recoil detection analysis

2013

Quantitative detection of pseudomonas corrugata and pseudomonas mediterranea in tomato plants by duplex real-time PCR

2011

Pseudomonas corrugata and P. mediterranea are two closely related bacterial species both causal agents of tomato pith necrosis. To screen tomato planting material reliably, a quantitative real-time PCR assay was developed, to detect and/or discriminate both bacterial pathogens in a single tube. So, two species-specific primer/probe sets were designed on the sequences of two DNA fragments amplified by a previously reported specific PCR protocol. TaqMan real-time PCR assays were developed for individual (simplex PCR) and simultaneous (duplex PCR) amplifications. The assays were performed with the SmartCycler TD II System (Cepheid) and the fluorescence from both FAM and Texas Red channels were…

A novel approach based on nonactive powers for the identification of disturbing loads in power systems

2007

In this paper, a new approach is proposed for the detection of harmonic sources in polluted power systems. It is a single- point strategy, based on a comparison among different "nonactive" power quantities proposed in literature that, in the same working conditions, assume different values at the same metering section. Some simulations tests were carried out on a standard IEEE test system proposed by other authors as a benchmark system for the analysis of multipoint measurement techniques for harmonic pollution monitoring. The obtained results show that the proposed single-point approach is in agreement with other strategies already proposed in the literature and can provide useful indicati…

Detection of disturbing loads in distorted and/or unbalanced power systems: a technique based on a comparison among nonactive powers

2007

This paper presents an innovative technique for the detection of disturbing loads in distorted power systems. It is a single-point strategy, based on a comparison among different "nonactive" power quantities already proposed in literature, that are measured at the same metering section. In the paper, the results obtained with the application of the proposed technique are compared with those of other techniques for the monitoring of the harmonic pollution, both single-point and multi-point. Moreover, the effectiveness of the strategy is discussed, considering also the errors of the measurement transducers.

Comparison of Nonactive Powers for the Detection of Dominant Harmonic Sources in Power Systems

2008

This paper deals with an innovative technique for the detection of disturbing loads in distorted power systems. The technique is a single-point strategy based on a comparison among different ldquononactiverdquo power quantities already proposed in the literature, which are measured at the same metering section. In this paper, the effectiveness of the strategy is discussed, which also considered the errors of the measurement transducers; the analysis is supported by simulation tests, which were carried out on both a simple single-phase system and an IEEE standard three-phase test power system. The latter was used by other authors as a benchmark system for the analysis of multipoint measureme…

Computer-Aided Diagnosis System with Backpropagation Artificial Neural Network—Improving Human Readers Performance

2016

This article presents the results of a study into possibility of artificial neural networks (ANNs) to classify cancer changes in mammographic images. Today’s Computer-Aided Detection (CAD) systems cannot detect 100 % of pathological changes. One of the properties of an ANN is generalized information —it can identify not only learned data but also data that is similar to training set. The combination of CAD and ANN could give better result and help radiologists to take the right decision.

Learning the structure of HMM's through grammatical inference techniques

2002

A technique is described in which all the components of a hidden Markov model are learnt from training speech data. The structure or topology of the model (i.e. the number of states and the actual transitions) is obtained by means of an error-correcting grammatical inference algorithm (ECGI). This structure is then reduced by using an appropriate state pruning criterion. The statistical parameters that are associated with the obtained topology are estimated from the same training data by means of the standard Baum-Welch algorithm. Experimental results showing the applicability of this technique to speech recognition are presented. >

One-Class Classifiers : A Review and Analysis of Suitability in the Context of Mobile-Masquerader Detection

2007

One-class classifiers employing for training only the data from one class are justified when the data from other classes is difficult to obtain. In particular, their use is justified in mobile-masquerader detection, where user characteristics are classified as belonging to the legitimate user class or to the impostor class, and where collecting the data originated from impostors is problematic. This paper systematically reviews various one-class classification methods, and analyses their suitability in the context of mobile-masquerader detection. For each classification method, its sensitivity to the errors in the training set, computational requirements, and other characteristics are consi…

Current-Based Measurement Technique for High Sensitivity Detection of Resistive Bridges With External Balancing Through Control Voltages

2017

We present a novel approach based on differential measurements of dc currents with very high sensitivity suitable for the detection of very small variations of resistors in Wheatstone full-bridge configurations. External control voltages allow for the compensation of the bridge unbalancing avoiding the need of changing its elements so making the solution suitable for integrated sensor systems. The proposed current-based measurement technique has been implemented through three different circuits, in transimpedance configuration and without the use of any further amplification stage, employing only two active blocks that allow for a very high integration level. The main characteristics of the…