1,697 research outputs found

    A comparative study on face recognition techniques and neural network

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    In modern times, face recognition has become one of the key aspects of computer vision. There are at least two reasons for this trend; the first is the commercial and law enforcement applications, and the second is the availability of feasible technologies after years of research. Due to the very nature of the problem, computer scientists, neuro-scientists and psychologists all share a keen interest in this field. In plain words, it is a computer application for automatically identifying a person from a still image or video frame. One of the ways to accomplish this is by comparing selected features from the image and a facial database. There are hundreds if not thousand factors associated with this. In this paper some of the most common techniques available including applications of neural network in facial recognition are studied and compared with respect to their performance.Comment: 8 page

    Design of Cognitive Radio Database using Terrain Maps and Validated Propagation Models

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    Cognitive Radio (CR) encompasses a number of technologies which enable adaptive self-programing of systems at different levels to provide more effective use of the increasingly congested radio spectrum. CRs have potential to use spectrum allocated to TV services, which is not used by the primary user (TV), without causing disruptive interference to licensed users by using appropriate propagation modelling in TV White Spaces (TVWS). In this paper we address two related aspects of channel occupancy prediction for cognitive radio. Firstly, we continue to investigate the best propagation model among three propagation models (Extended-Hata, Davidson-Hata and Egli) for use in the TV band, whilst also finding the optimum terrain data resolution to use (1000, 100 or 30 m). We compare modelled results with measurements taken in randomly-selected locations around Hull UK, using the two comparison criteria of implementation time and accuracy, when used for predicting TVWS system performance. Secondly, we describe how such models can be integrated into a database-driven tool for CR channel selection within the TVWS environment by creating a flexible simulation system for creating a TVWS database

    A slot-loaded reduced-size CPW-fed aperture antenna for UWB applications

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    The paper presents a co-planar wave guide (CPW)-fed slot loaded low return loss planar printed antenna with a small size designed for wireless communication and UWB applications. First, a conventional UWB antenna is modeled to provide a reference point for the modeling and then the shape is modified by a self inverted configuration to achieve higher bandwidth and size reduction. To improve the gain and efficiency, a combination of corner features and loading slots are introduced. The primary aim throughout the modeling was to achieve the minimum possible value of return loss (S11) below -10 dB over the FCC-defined UWB frequency range. The antenna was designed, simulated and modified using Agilent's Advanced Design System (ADS). It was fabricated on FR4 substrate and measured return loss results are presented

    System model for the evaluation of interference "Cosite Analysis Model"

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    There is an increasing demand to solve the interference between wireless communication systems. This means in particular to antenna networks that placed near together such as radio mast as well at warship and airplane antenna. In this case the system may become limited by interference rather than anything else. One promising technology for radio station in interference-limited systems is Cosite Analysis Model (COSAM). This is technology allows both for reducing the space between antenna and reducing interference in the same time. As result, can reducing the proliferation of towers. The aim of this project is to introduce comprehensive case study about an integrate cosite system models for the evaluation of interference between antennas. Furthermore, since that the most important reason of interference is intermodulation (IM); this project introduces an intermodulation product interference detection and analysis tools. One of promising method which will use in this project is known as Method of Performing Antenna Cosite Analysis using Intermodulation Technique. The main power of this method is to analyze and detect all possible intermodulation products that could cause interference

    Relationship between synaptic dysfunction and degeneration in a rodent model of dementia

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    Synaptic degeneration is currently the best biomarker correlate of cognitive decline in dementia. In the years prior to dementia onset, many neurophysiological changes are occurring hypothesised to preserve cognitive function, including alterations in synaptic and neuronal function. This thesis aims to characterise the early synaptic and neurophysiological alterations occurring in a mouse model of tauopathy-driven neurodegeneration (rTg4510). This work was performed in the somatosensory cortex, a well characterised region of the brain in the mouse, which serves as a prototypical model of the neocortex. The work presented in Chapters two and three revealed alterations in synaptic glutamatergic receptor function (reduced NMDA:AMPA receptor ratio) and intrinsic neuronal properties in prodromal tauopathy in rTg4510 mice, using in vitro whole-cell patch clamp electrophysiology. Increased dendritic branching proximal to the soma was seen in these recorded neurons following post hoc imaging of their structure. In more advanced stages of tauopathy, reductions in putative AMPA receptor-mediated spontaneous synaptic activity was observed. Significant reductions in glutamatergic receptor expression and synaptic markers was detected in both prodromal and more advanced tauopathy, quantified from isolated synaptosomes. To characterise how glutamatergic receptor dysfunction manifested in vivo, recording paradigms were optimised for in vivo two-photon targeted whole-cell patch clamp electrophysiology, outlined in Chapter four. This technique was used to simultaneously record subthreshold synaptic properties, network activity, and evoked synaptic responses in the rTg4510 model in early neurodegeneration in Chapter five. Whilst spontaneous network activity was similar between genotypes, there was an observable increase in the fast peak response of evoked activity. This work suggests that synaptic dysfunction is a feature of both prodromal and advanced tauopathy, with different functional and biochemical correlates manifesting at different stages of disease progression. Further characterisation of these processes, and how this contributes to symptomatic decline, can provide a basis to develop novel therapeutic strategies to alleviate tau-mediated synaptic and neuronal dysfunction prior to widespread cell loss

    Inverse parameter identification of elastic and inelastic constitutive material models

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    Formulating the complete description of a material behavior includes finding the numerical values of parameters involved in its constitutive equations [I]. Traditionally, this is based on running some experimental tests and manipulating their results in order to extract the values of these parameters [2]. This chapter presents an alternative approach, based on inverse problems, which will provide a numerical method for determining accurate material parameters. This numerical tool combines an optimization algorithm with a finite element solver giving the material response to arbitrary loading. Two numerical examples are used to demonstrate the effectiveness of the developed identification techniqu

    Joint Learning of Pre-Trained and Random Units for Domain Adaptation in Part-of-Speech Tagging

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    Fine-tuning neural networks is widely used to transfer valuable knowledge from high-resource to low-resource domains. In a standard fine-tuning scheme, source and target problems are trained using the same architecture. Although capable of adapting to new domains, pre-trained units struggle with learning uncommon target-specific patterns. In this paper, we propose to augment the target-network with normalised, weighted and randomly initialised units that beget a better adaptation while maintaining the valuable source knowledge. Our experiments on POS tagging of social media texts (Tweets domain) demonstrate that our method achieves state-of-the-art performances on 3 commonly used datasets

    A comparison of CK and Martin's package metric suites in predicting reusability in open source object-oriented software

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    Packages are units that organize source code in large object-oriented systems. Metrics used at the package granularity level mostly characterize attributes such as complexity, size, cohesion and coupling. Many of these characterized attributes have direct relationships with the quality of the software system being produced. Empirical evidence is required to support the collection of measures for such metrics; hence these metrics are used as early indicators of such important external quality attributes. This research compared the CK and Martin’s package metric suites in order to characterize the package reusability level in object-oriented software. Comparing the package level of metrics suites as they measure an external software quality attribute is supposed to help a developer knows which metric suite can be used to effectively predict the software quality attribute at package level. In this research two open source Java applications, namely; jEdit and BlueJ were used in the evaluation of two package metrics suites, and were compared empirically to predict the package reusability level. The metric measures were also used to compare the effectiveness of the metrics in these package metrics suites in evaluating the reusability at the package granularity level. Thereafter metric measures of each package were normalized to allow for the comparison of the package reusability level among packages within an application. The Bansiya reusability model equation was adapted as a reusability reference quality model in this research work. Correlation analysis was performed to help compare the metrics within package metrics suites. Through the ranking of the package reusability level, results show that the jEdit application has 30% of its packages ranked with a very high reusability level, thus conformed to the Pareto rule (80:20). This means that the jEdit application has packages that are more reusable than packages in the BlueJ application. Empirically, the Martin’s package coupling metric Ce with an r value of 0.68, is ranked as having a positive strong correlation with RL, and this has distinguished the Martin’s package metrics suite as an effective predictor of package reusability level from the CK package metrics suite
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