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Investigation of two-phase and three-phase relative permeability in different rocks with similar pore size distribution 75

Investigation of two-phase and three-phase relative permeabi...

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75th European Association of Geoscientists and Engineers conference and Exhibition 2013 Incorporating SPE EUROPEC 2013: Changing Frontiers

作者： Shahverdi, H. Sohrabi, M. Fatemi, S.M. Ireland, Shaun Centre for Enhanced Oil Recovery and CO2 Solutions Institute of Petroleum Engineering Heriot-Watt University United Kingdom

ISBN: (纸本)9781629937915

Relative permeability (kr) function describes the comparative ease by which different fluids flow in a porous medium and plays an influential role in numerical simulation of petroleum reservoirs. Since, the measurement of relative permeability, especially three-phase ones, in laboratories is time consuming and expensive, much research has directed towards developing correlations for estimating the three-phase relative permeability values. One assumption used in reservoir simulation is that relative permeability curves of different rocks with similar lithology and pore size distribution depict identical behaviour if expressed against normalised (mobile) fluid saturations. This paper present the results of a study carried out to assess the validity of this assumption for two-phase and three-phase flow systems. A set of two-phase (oil/gas) and three-phase (oil/gas/water) unsteady-state coreflood experiments were conducted on two Clashach sandstone samples with permeabilities of 1000 mD and 65 mD. The relative permeability curves for each experiment were then obtained by mathematical modelling of the coreflood tests and matching the laboratory measured data. Comparison between the measured two-phase oil/gas kr of the two cores show that the relative permeability curves versus mobile (normalized) saturation for the 1000 mD core are close to that of the 65 mD rock. This demonstrates that in the absence of measured relative permeability data for a low permeability core, the available data for a higher permeability core with similar lithology can be used for the low permeability rock and vice versa. However, this was not the case for three-phase kr. Comparison of the three-phase relative permeability obtained for water, oil and gas in the two cores shows significant difference for the two cores even when plotted againest normalized saturations. Hence, the simulation of the coreflood experiment involving three-phase flow carried out on the 65 mD core using the relative perme

关键词： Petroleum reservoir engineering

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Parallels between wind and crowd loading of bridges

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PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-mathematical PHYSICAL AND engineering SCIENCES 2013年第1993期371卷 20120430-20120430页

作者： McRobie, Allan Morgenthal, Guido Abrams, Danny Prendergast, John Univ Cambridge Dept Engn Cambridge CB2 1PZ England Bauhaus Univ Weimar D-99421 Weimar Germany Northwestern Univ Dept Engn Sci & Appl Math Evanston IL 60208 USA Renewable Energy Syst Ltd Kings Langley WD4 8LR England

Parallels between the dynamic response of flexible bridges under the action of wind and under the forces induced by crowds allow each field to inform the other. Wind-induced behaviour has been traditionally classified into categories such as flutter, galloping, vortex-induced vibration and buffeting. However, computational advances such as the vortex particle method have led to a more general picture where effects may occur simultaneously and interact, such that the simple semantic demarcations break down. Similarly, the modelling of individual pedestrians has progressed the understanding of human-structure interaction, particularly for large-amplitude lateral oscillations under crowd loading. In this paper, guided by the interaction of flutter and vortex-induced vibration in wind engineering, a framework is presented, which allows various human-structure interaction effects to coexist and interact, thereby providing a possible synthesis of previously disparate experimental and theoretical results.

关键词： bridges dynamics wind human-structure interaction aeroelasticity

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Requirements modelling by Synthesis of Deontic Input-Output Automata 13

Requirements Modelling by Synthesis of Deontic Input-Output ...

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International conference on Software engineering

作者： Emmanuel Letier William Heaven University College London UK

ISBN: (纸本)9781467330763

Requirements modelling helps software engineers understand a system's required behaviour and explore alternative system designs. It also generates a formal software specification that can be used for testing, verification, and debugging. However, elaborating such models requires expertise and significant human effort. The paper aims at reducing this effort by automating an essential activity of requirements modelling which consists in deriving a machine specification satisfying a set of goals in a domain. It introduces deontic input-output automata - an extension of input-output automata with permissions and obligations - and an automated synthesis technique over this formalism to support such derivation. This technique helps modellers identifying early when a goal is not realizable in a domain and can guide the exploration of alternative models to make goals realizable. Synthesis techniques for input-output or interface automata are not adequate for requirements modelling.

关键词： Tuners Transient analysis Semantics Automata Context Adaptation models

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Vibration behaviour of the asynchronous machine magnetic core

Vibration behaviour of the asynchronous machine magnetic cor...

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European conference on Power Electronics and Applications

作者： Luká? Bouzek Roman Pechánek UNIVERSITY OF WEST BOHEMIA/FACULTY OF ELECTRICAL ENGINEERING/RICE Univerzitni 8 Pilsen Czech Republic

This paper deals with the effect of laminations on natural frequencies of asynchronous machine magnetic core. Measurement of natural frequency of stator core is presented. Numerical model and calculation of natural fr... 详细信息

ISBN: (纸本)9781479901159

关键词： Electrical machine Induction motor Simulation modelling Asynchronous motor

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human-human Interaction using a behavioural Control Strategy

Human-Human Interaction using a Behavioural Control Strategy

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IEEE conference on Technologies for Practical Robot Applications

作者： Paramin Neranon Robert Bicker School of Mechanical and Systems Engineering Stephenson Building Newcastle University

ISBN: (纸本)9781467362238

This paper presents an outline of human-human interaction to establish a framework to understand how a behaviour based approach can be developed in the design of a human-robot interactive strategy. To approach the conceptual design guidelines for an interactive human-robot strategy, the mathematical model of human behaviour during transferring the compliant object to a receiver without any types of communication has been strategically analysed. The Auto Regressive Moving Average with Exogenous Input (ARMAX) system identification has been applied to identify the human arm model. A set of experiments have been designed (based on Box-Behnken), along with the influence variables affecting the human forces, which consist of mass, friction and target displacement. The estimated ARMAX models were shown to be good matching with the actual experimental data, where the best-fit percentages of human force profiles are between 88.73% - 97.2%;the proposed models can then be used to present the human arm characteristics effectively.

关键词： human-robot interaction Compliant object human-human interaction ARMAX Box-Behnken

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Centrality and spectral radius in dynamic communication networks

Centrality and spectral radius in dynamic communication netw...

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19th International Computing and Combinatorics conference, COCOON 2013

作者： Vukadinović Greetham, Danica Stoyanov, Zhivko Grindrod, Peter Centre for the Mathematics of Human Behaviour Department of Mathematics and Statistics University of Reading United Kingdom

ISBN: (纸本)9783642387678

We explore the influence of the choice of attenuation factor on Katz centrality indices for evolving communication networks. For given snapshots of a network observed over a period of time, recently developed communicability indices aim to identify best broadcasters and listeners in the network. In this article, we looked into the sensitivity of communicability indices on the attenuation factor constraint, in relation to spectral radius (the largest eigenvalue) of the network at any point in time and its computation in the case of large networks. We proposed relaxed communicability measures where the spectral radius bound on attenuation factor is relaxed and the adjacency matrix is normalised in order to maintain the convergence of the measure. Using a vitality based measure of both standard and relaxed communicability indices we looked at the ways of establishing the most important individuals for broadcasting and receiving of messages related to community bridging roles. We illustrated our findings with two examples of real-life networks, MIT reality mining data set of daily communications between 106 individuals during one year and UK Twitter mentions network, direct messages on Twitter between 12.4k individuals during one week. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Eigenvalues and eigenfunctions

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Semi-interactive region segmentation based on sparse representation

Semi-interactive region segmentation based on sparse represe...

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IEEE India conference (INDICON)

作者： Raju Ranjan Sumana Gupta K S Venkatesh Department of Electrical Engineering Indian Institute of Technology Kanpur Kanpur

Region segmentation is an important and challenging task. The applications range from tumour detection in medical imaging, computer aided surveillance, object location, pattern separation etc. Sparsity based data modelling in recent times have produced state of the art results in many image processing tasks. In this paper, we propose a semi-interactive region segmentation in sparse framework. Proper data modelling is the key to learning based segmentation. We propose a hybrid feature vector which is a combination of weighted RGB values and the proposed histogram estimated by first multiplying Gaussian weight to each count of the pixel intensity according to its respective position in the patch. We study the effect of various parameters such as patch size, number of atoms in dictionary, number of training feature vectors and sparsity constraint on the segmentation behaviour. We test our proposed segmentation algorithm on the subset of images from BSDS300 (Berkeley Segmentation Dataset).

关键词： Image segmentation Dictionaries Vectors Training Image color analysis mathematical model Histograms

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Simulation and analysis of RTS/CTS DoS attack variants in 802.11 networks

Simulation and analysis of RTS/CTS DoS attack variants in 80...

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International conference on Pattern Recognition, Informatics and Medical engineering

作者： P M D Nagarjun V. Anil Kumar Ch Aswani Kumar Ahkshaey Ravi School of Information Technology & Engineering VIT University Vellore India CSIR Centre for Mathematical Modelling and Computer Simulation Bangalore India

Denial-of-Service attacks (DoS) have become a widespread problem on the Internet. These attacks are easy to execute. Low rate attacks are relatively new variants of DoS attacks. Low rate DoS attacks are difficult to detect since attacker sends attack stream with low volume and the countermeasures used to handle the high rate DoS attacks are not suitable for these types of attacks. RTS/CTS attack is one type of Low rate DoS attack. In this paper, we analyze RTS/CTS attack which exploits the medium reservation mechanism of 802.11 networks through duration field. We propose variants of RTS/CTS attacks in wireless networks. We simulate the attacks behaviour in ns2 simulation environment to demonstrate the attack feasibility as well as potential negative impact of these attacks on 802.11 based networks. We have created an application that has the capability to create test bed environment for the attacks, perform RTS/CTS attacks and generate suitable graphs to analyze the attack's behaviour. We also briefly discuss possible ways of detecting and mitigating such Low rate DoS attacks in wireless networks.

关键词： IEEE 802.11 Standards Computer crime Wireless networks Ad hoc networks Receivers Pattern recognition Informatics

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Wave energy production in Italian offshore: Preliminary design of a point absorber with tubular linear generator

Wave energy production in Italian offshore: Preliminary desi...

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International conference on Clean Electrical Power (ICCEP)

作者： S. Bozzi A. Moreno Miquel F. Scarpa A. Antonini R. Archetti G. Passoni G. Gruosso Department of Electronics Information Science and Bioengineering Politecnico di Milano Milano Italy Department of Civil Environmental and Materials Engineering University of Bologna Bologna Italy

The paper presents the preliminary design and modelling of a point absorber wave energy converter consisting of a floating buoy connected to a tubular linear generator fixed at the seabed. The behaviour of the device is described by the equation of motion of a single body system restricted to vertical motion. The model of the coupled buoy-generator system is used to simulate the behaviour of the wave energy converter under regular waves of different heights and periods. Then the electricity production of an hypothetical installation off the Alghero coast is estimated. The results show that the device capacity factor at the study site is around 15%. This is a very promising value considering that the studied device has not been specifically optimized for the Alghero wave climate. The work suggests that the presented technology could be very attractive for the Italian offshore.

关键词： Generators Sea state mathematical model Force Production Meteorology Equations

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modelling and management of strain situations in hospital systems using an ORCA approach

Modelling and management of strain situations in hospital sy...

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International conference on Industrial engineering and Systems Management (IESM)

作者： Farid Kadri Cyrille Pach Sondès Chaabane Thierry Berger Damien Trentesaux Christian Tahon Yves Sallez Univ. Lille Nord de France Valenciennes France

Management of patient flow, especially the flow resulting from health crises (exceptional situations) in emergency departments (ED), is one of the most important problems ED managers have to deal with. Emergency departments require significant human and material resources to handle this influx of patients, but these are limited and so the medical and paramedical staff are often confronted with strain situations. To deal with these situations, emergency departments have no choice but to adapt. The main purpose of this paper is to characterize these strain situations and introduce a new framework to model these situations in an emergency department (ED) in order to improve their management by the hospital system. The proposed framework integrates an ORCA (Architecture for an Optimized and Reactive Control) approach to proactively schedule (where possible) the behaviour of a hospital system and to handle strain situations reactively.

关键词： Strain Hospitals Computer architecture Materials Production Control systems

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