8,432 research outputs found

    Town centre improvements through sustainable procurement

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    The project is investigating the potential to reduce town centre business costs and negative environmental impacts through the use of innovations in procurement and freight transport. These innovations include collaborative procurement, Business Improvement Districts, and Delivery and Servicing Plans. These approaches were being trialled and evaluated in three British towns: Cambridge, Lowestoft and Norwich. 17 companies were developing and applying a Delivery and Servicing Plan. Transport reduction effects were achieved

    Microfog lubricant application system for advanced turbine engine components, phase 3

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    The wetting characteristics and deposit forming tendencies of a series of lubricants were evaluated using a microfog jet delivery system to wet a flat heated rotating disc. The performances of the nine lubricants are discussed in terms of the various testing parameters which include temperature, disc speed and lubricant gas flow rates. Also discussed are the heat transfer characteristics of two of the lubricants on that same plane disc specimen. The wetting characteristics and heat transfer characteristics of one of the lubricants on a complex disc simulating bearing geometry are also discussed

    Perturbative unitarity bounds for effective composite models

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    In this paper we present the partial wave unitarity bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a compositeness scenario. These are routinely used in experimental searches at the LHC to constraint contact and gauge interactions between ordinary Standard Model fermions and excited (composite) states of mass MM. After deducing the unitarity bound for the production process of a composite neutrino, we implement such bound and compare it with the recent experimental exclusion curves for Run 2, the High-Luminosity and High-Energy configurations of the LHC. Our results also applies to the searches where a generic single excited state is produced via contact interactions. We find that the unitarity bound, so far overlooked, is quite complelling and significant portions of the parameter space (M,ΛM,\Lambda) become excluded in addition to the standard request MΛM \le \Lambda.Comment: This version of the paper merges the previous version published in Phys. Lett. B 795 (2019) 644-649 (https://doi.org/10.1016/j.physletb.2019.06.042) with the subsequent Erratum currently in press in Physics Letters B (https://doi.org/10.1016/j.physletb.2019.134990

    AVIR – Audio-Visual Indexing and Retrieval for Non IT Expert Users

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    The AVIR proposal originates from the demand for new solutions allowing common users to easily access, store and retrieve relevant audio-visual information from the vast amounts of resources at their disposal. The next generation of television systems will be connected to many sources of information and entertainment (TV-and radio from air, cable or satellite, video and audio libraries, video tape/disk recorders, Internet). Literally hundreds of channels will soon be offered to the user, which could be disoriented by this overload of information. Users will not pay for just more extra channels, but will appreciate if the content in the channels is easily accessible and, more importantly, can be easily selected according to the user's personal interest. This can only be achieved if the broadcaster delivers meta-data describing the actual content in sufficient detail enabling for automatic handling by agents residing on the end user's system. AVIR investigates on novel procedures for automatic analysis and indexing of audio-visual information, specifically meant to support consumer services. The objective of this project is to investigate and experiment end-to-end solutions for delivering new added value services on top of digital video broadcast services, which will enable a better exploitation of multimedia information resources by non-IT experts. As a result the project is building a prototype service user platform and will demonstrate its feasibility on a broadcast delivery chain. It takes into account extraction of high quality meta-data and electronic delivery of meta-data associated to audio-visual content, including adaptation of consumer receivers and recorders towards a personalized multimedia repository. Intelligent agents based on a user interest profile will help the user to browse and access most relevant programmes via an intelligent, personal electronic guide. A low cost, high capacity home storage device, will also be used to increment the capabilities of the consumer system. Thanks to the received descriptors, advanced retrieval features can be implemented on the stored assets and, in combination with the user’s profile, automatic recording feature is possible. A visual navigation system, a search engine and agents will help the user identifyvideo material of interest on the home video-recorder, transfo rming it into a personal multimedia repository

    Indoor radon survey in university buildings: a case study of Sapienza - University of Rome

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    The indoor radon concentration in underground workplaces pertaining to Sapienza – University of Rome have been monitored since the 90’s according to prescription of Italian Legislative Decree 230/95. In the last years, the recommendations contained in the Council Directive 2013/59/Euratom have shifted the focus to all indoor exposure situations by promoting actions to identify workplaces and dwellings with radon concentrations exceeding the reference level of 300 Bq/m3. In response to the upcoming transposition into national legislation, Sapienza has promoted the first Italian survey addressing workplaces in university buildings, regardless of the position with respect to the ground floor. The survey has interested more than three hundred workplaces, i.e. administration and professors’ offices, research and educational laboratories, conference rooms and classrooms, distributed in fifteen different buildings. Places monitored are strongly heterogeneous in terms of users’ habit, occupancy pattern and building characteristics. The influence of these parameters into seasonal variation have been addressed by organizing the survey in four quarters. The indoor radon concentration is measured by solid state nuclear track detectors, CR39. The aim of the paper is to present features, methods and intermediate results of the survey. The work, relying on the analysis of previous measurements interesting underground workplaces, focuses on methodology followed during all the preliminary and preparatory phases: active measurements by ionization chamber radon continuous monitor, radon progeny equilibrium factor estimations by radon daughters monitor, strategies for occupants’ awareness, positioning protocol and provisions to maximize representativity of results

    Hunting for heavy composite Majorana neutrinos at the LHC

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    We investigate the search for heavy Majorana neutrinos stemming from a composite model scenario at the upcoming LHC Run II at a center of mass energy of 13 TeV. While previous studies of the composite Majorana neutrino were focussed on gauge interactions via magnetic type transition coupling between ordinary and heavy fermions (with mass mm^*) here we complement the composite model with contact interactions at the energy scale Λ\Lambda and we find that the production cross sections are dominated by such contact interactions by roughly two/three orders of magnitude. This mechanism provides therefore very interesting rates at the prospected luminosities. We study the same sign di-lepton and di-jet signature (ppjjpp \to \ell\ell jj) and perform a fast detector simulation based on Delphes. We compute 3σ\sigma and 5σ\sigma contour plots of the statistical significance in the parameter space (Λ,m\Lambda,m^*). We find that the potentially excluded regions at s=13\sqrt{s} =13 TeV are quite larger than those excluded so far at Run I considering searches with other signatures.Comment: 14 pages, 9 figures, Minor comments and few references added. Version accepted by the European Physical Journal C (EPJC

    Estimating Dynamic Traffic Matrices by using Viable Routing Changes

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    Abstract: In this paper we propose a new approach for dealing with the ill-posed nature of traffic matrix estimation. We present three solution enhancers: an algorithm for deliberately changing link weights to obtain additional information that can make the underlying linear system full rank; a cyclo-stationary model to capture both long-term and short-term traffic variability, and a method for estimating the variance of origin-destination (OD) flows. We show how these three elements can be combined into a comprehensive traffic matrix estimation procedure that dramatically reduces the errors compared to existing methods. We demonstrate that our variance estimates can be used to identify the elephant OD flows, and we thus propose a variant of our algorithm that addresses the problem of estimating only the heavy flows in a traffic matrix. One of our key findings is that by focusing only on heavy flows, we can simplify the measurement and estimation procedure so as to render it more practical. Although there is a tradeoff between practicality and accuracy, we find that increasing the rank is so helpful that we can nevertheless keep the average errors consistently below the 10% carrier target error rate. We validate the effectiveness of our methodology and the intuition behind it using commercial traffic matrix data from Sprint's Tier-1 backbon

    QoE in Pull Based P2P-TV Systems: Overlay Topology Design Tradeoff

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    Abstract—This paper presents a systematic performance anal-ysis of pull P2P video streaming systems for live applications, providing guidelines for the design of the overlay topology and the chunk scheduling algorithm. The contribution of the paper is threefold: 1) we propose a realistic simulative model of the system that represents the effects of access bandwidth heterogeneity, latencies, peculiar characteristics of the video, while still guaranteeing good scalability properties; 2) we propose a new latency/bandwidth-aware overlay topology design strategy that improves application layer performance while reducing the underlying transport network stress; 3) we investigate the impact of chunk scheduling algorithms that explicitly exploit properties of encoded video. Results show that our proposal jointly improves the actual Quality of Experience of users and reduces the cost the transport network has to support. I

    Simple Tools for Abstraction and Instantiation

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    A simplified version of tools for abstraction and instantiation [1,2,3] are proposed here. The tools are merely two new attributes applicable to any DS instances. The merit of abstraction and instantiation is the economy of description and clarification of structural commonality. Abstractions allow you to avoid repeating similar descriptions. You write one template to address the shared structure of descriptions and reuse it when you want similar descriptions. Suppose you want to describe many occurrences of a common pattern of events and states of affairs, such as a type of configuration of soccer players in the field. You will describe the positions of eleven or twenty two people to address this configuration. Once you have described this common pattern, you can capture each occurrence of the pattern by just substituting the eleven or twenty-two people to with particular players, without repeating the descriptions of their positions, among others. Although the AbstractionLevel DataType in MPEG-7 FDIS is apparently claimed to address abstraction and instantiation, its usage and semantics have not been clarified enough to actually employ it. What follows should provide a far simpler and practically usable set of tools for abstraction and instantiation
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