DCU Online Research Access Service

    Formulating queries for collecting training examples in visual concept classification

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    Video content can be automatically analysed and indexed using trained classifiers which map low-level features to semantic concepts. Such classifiers need training data consisting of sets of images which contain such concepts and recently it has been discovered that such training data can be located using text-based search to image databases on the internet. Formulating the text queries which locate these training images is the challenge we address here. In this paper we present preliminary results on TRECVid data of concept classification using automatically crawled images as training data and we compare the results with those obtained from manually annotated training sets

    Thermal stability of laser treated die material for semi-solid metal forming

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    This paper presents laser surface modification work performed to improve the lifetime of die materials. Die material AISI H13, with typical hardness in the range of 42 to 48 HRC, offers high wear and corrosion resistance. However the cyclic high temperature conditions along with exposure to high viscosity molten metal in semi-solid forming cause the die to wear and crack with resultant shortened die lifetime. In this study, the thermal stability of die material at elevated temperature was investigated through micro-hardness testing and a metallographic study. AISI H13 samples were laser glazed using CO2 continuous wave mode laser with 10.6 µm wavelength. Samples were attached to a specially designed rotating chuck to enable it to be rotated at speeds up to 1500 rpm and allow flat surface glazing to take place. The micro-hardness was measured for as-glazed samples and annealed samples which were held at temperatures ranging from 550oC to 800oC with 50oC intervals. The metallographic study conducted examined the formation of three zones at different depths which were the glazed zone, the heat affected zone and the substrate. As a result of rapid heating and cooling from the laser glazing process, a metallic glass layer was developed which exhibited an average micro-hardness of 900 HV when exposed to 3.34E+10 W/m2 laser irradiance within a range of 3.64 to 5.66 ms exposure time. Crystallization in glazed zone increased as the annealing temperature increased. As the annealing temperature reached above approximately 600oC, the micro-hardness decreased to approximately 600 HV (equivalent to approx. 54 HRC) due to local crystallization. These findings show potential direct application of glazed dies for non-ferrous semi-solid forming and the requirement for thermal barrier protection for application at higher temperatures

    Orthogonal variability modeling to support multi-cloud application configuration

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    Cloud service providers benefit from a vast majority of customers due to variability and making profit from commonalities between the cloud services that they provide. Recently, application configuration dimensions has been increased dramatically due to multi-tenant, multi-device and multi-cloud paradigm. This challenges the configuration and customization of cloud-based software that are typically offered as a service due to the intrinsic variability. In this paper, we present a model-driven approach based on variability models originating from the software product line community to handle such multi-dimensional variability in the cloud. We exploit orthogonal variability models to systematically manage and create tenant-specific configuration and customizations. We also demonstrate how such variability models can be utilized to take into account the already deployed application parts to enable harmonized deployments for new tenants in a multi-cloud setting. The approach considers application functional and non-functional requirements to provide a set of valid multi-cloud configurations. We illustrate our approach through a case study

    A sleep bruxism detection system based on sensors in a splint – pilot clinical data

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    It is difficult in a dental setting to accurately diagnose sleep bruxism and to objectively assess the severity, frequency or natural history of the condition in an individual patient. Yet this information is essential for the management of sleep bruxism and to plan appropriate dental treatment. The objective of this study was to clinically test a device that could be used to record bruxism events in a home environment. Pressure sensors were developed for use under the surface of an occlusal splint, and circuitry was designed to facilitate the recording and wireless transmission of the pressure sensor signal to a computer. Controlled mandibular movements were carried out in vivo to simulate bruxism and non-bruxism patterns. These patterns of force application were graphically presented to two examiners who were asked to identify the type of activity represented by the force curves. Examiners were largely able to distinguish bruxism from non-bruxism activity; the sensitivity ranged from 80% to 100% and the specificity from 75% to 100%. Using sensors in an occlusal splint, it is possible to recognise the typical tooth contact patterns seen in sleep bruxism. Such a device may be useful for monitoring sleep bruxism over an extended period at home

    Porting a summarizer to the French language

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    We describe the porting of the English language REZIME text summarizer to the French language. REZIME is a single-document summarizer particularly focused on summarization of medical documents. Summaries are created by extracting key sentences from the original document. The sentence selection employs machine learning techniques, using statistical, syntactic and lexical features which are computed based on specialized language resources. The REZIME system was initially developed for English documents.In this paper we present the summarizer architecture, and describe the steps required to adapt it to the French language. The summarizer performance is evaluated for English and French datasets. Results show that the adaptation to French results in a system performance comparable to English

    Generation and control of reactive species in low temperature atmospheric pressure plasma sources.

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    This work presents results of novel numerical studies investigating the interaction of plasma, gas and heat dynamics for a variety of popular source geometries. Plasma produced chemistry and heat flux reaching a treatment surface is investigated offering fundamental insight into induced plasma effects. Control opportunities for reactive species delivery and heat limitation is investigated in this context. The mixing of helium and air species in a corona plasma jet(’plasma needle’) is shown to define the shape and composition of the plasma region. Numerical analysis reveals an electropositive plasma core surrounded by an electro-negative edge reflecting the gas mixture profile. This non-uniform plasma results in non-uniform reactive species production. Circular and annular killing patterns recently found on bacteria treated by the source is shown here to correlate with atomic oxygen distributions at the surface. Interaction of the source with an aqueous surface reveals hydrogen peroxide as the dominant species dissolving at this interface. Atomic oxygen produced by O2 admixing to helium in a capacitively coupled jet(’micro-Atmospheric Pressure Plasma Jet’) is shown to quickly convert to ozone for increasing device to surface separation. Gas heating is dominated by elastic electron collisions and positive ion heating. Power modulation of a capacitively coupled jet(’micro-Atmospheric Pressure Plasma Jet’) is demonstrated as a mechanism for control of reactive species and heat flux delivery to a surface. Power is found to be coupled extensively to the electrons with large initial electron losses leading to weak interference between successive modulation phases. Frequency variation in a dielectric barrier discharge plasma source driven in the ~kHz frequency range is shown here to vary power deposition to the plasma by changing the interval between current pulses. O2(a1D) and O3 production is found to be coupled strongly to the O2 admixture

    Head first: living labs for ad-hoc search evaluation

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    The information retrieval (IR) community strives to make evaluation more centered on real users and their needs. The living labs evaluation paradigm, i.e., observing users in their natural task environments, offers great promise in this regard. Yet, progress in an academic setting has been limited. This paper presents the first living labs for the IR community benchmarking campaign initiative, taking as test two use-cases: local domain search on a university website and product search on an e-commerce site. There are many challenges associated with this setting, including incorporating results from experimental search systems into live production systems, and obtaining sufficiently many impressions from relatively low traffic sites. We propose that head queries can be used to generate result lists offline, which are then interleaved with results of the production system for live evaluation. An API is developed to orchestrate the communication between commercial parties and benchmark participants. This campaign acts to progress the living labs for IR evaluation methodology, and offers important insight into the role of living labs in this space

    The luminescent properties of CuAlO2

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    In this work we examine the room temperature photoluminescence, Raman and low temperature photoluminescence properties of CuAlO2 prepared using different precursors. At room temperatures the luminescence associated with bulk CuAlO2 occurs at 355 nm and is associated with strong resonant Raman effects. At low temperatures we find that the UV emission is dominated by strong electron– phonon coupling leading to a Franck–Condon type emission band. A second strongly phonon coupled band is also observed in the blue spectral region. In addition we also show that at low temperatures the luminescent properties of CuAlO2 are meta-stable, with anomalous temperature dependence. The possible origins of the blue band, the meta-stability and anomalous temperature dependence are discussed

    The development of a theoretical and computational framework for ultrafast processes of complex atomic systems in a strong radiation field

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    A time-dependent density matrix approach is used to investigate the effects of strong laser fields on the ionisation dynamics of complex atomic systems. In particular, two-step ionisation of neon and lithium with autoionising state (AIS) resonances are investigated and the effects of the resonances on the ion yields is determined. The stochasticity of a free-electron laser (FEL) pulse due to phase fluctuations is also modelled by using the phase diffusion model to obtain field-averaged time-dependent density matrix equations. A rate equation method is also investigated and analysed for reliability. One of the main advances developed in this work is the use of the density matrix method to investigate two-electron continuum states. For the neon system, the dependence of the branching ratios of singly and doubly ionised neon on the field intensity and duration is investigated. The rate equation method was also developed for this system in order to test its applicability. The possibility of single-colour AIS-AIS resonances in lithium is also investigated. To the author’s knowledge, no such system has been examined either theoretically, or experimentally. Thus, this work provides a first investigation into two new topics
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