2,590 research outputs found

    Matrix Models for Supersymmetric Chern-Simons Theories with an ADE Classification

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    We consider N=3 supersymmetric Chern-Simons (CS) theories that contain product U(N) gauge groups and bifundamental matter fields. Using the matrix model of Kapustin, Willett and Yaakov, we examine the Euclidean partition function of these theories on an S^3 in the large N limit. We show that the only such CS theories for which the long range forces between the eigenvalues cancel have quivers which are in one-to-one correspondence with the simply laced affine Dynkin diagrams. As the A_n series was studied in detail before, in this paper we compute the partition function for the D_4 quiver. The D_4 example gives further evidence for a conjecture that the saddle point eigenvalue distribution is determined by the distribution of gauge invariant chiral operators. We also see that the partition function is invariant under a generalized Seiberg duality for CS theories.Comment: 20 pages, 3 figures; v2 refs added; v3 conventions in figure 3 altered, version to appear in JHE

    Pressure-dependent EPANET extension

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    In water distribution systems (WDSs), the available flow at a demand node is dependent on the pressure at that node. When a network is lacking in pressure, not all consumer demands will be met in full. In this context, the assumption that all demands are fully satisfied regardless of the pressure in the system becomes unreasonable and represents the main limitation of the conventional demand driven analysis (DDA) approach to WDS modelling. A realistic depiction of the network performance can only be attained by considering demands to be pressure dependent. This paper presents an extension of the renowned DDA based hydraulic simulator EPANET 2 to incorporate pressure-dependent demands. This extension is termed “EPANET-PDX” (pressure-dependent extension) herein. The utilization of a continuous nodal pressure-flow function coupled with a line search and backtracking procedure greatly enhance the algorithm’s convergence rate and robustness. Simulations of real life networks consisting of multiple sources, pipes, valves and pumps were successfully executed and results are presented herein. Excellent modelling performance was achieved for analysing both normal and pressure deficient conditions of the WDSs. Detailed computational efficiency results of EPANET-PDX with reference to EPANET 2 are included as well

    TowardSelf-Replication of Robot Control Circuitry by Self-Inspection

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    Abstract. The concept of man-made self-replicatingm achines was first proposed by John von Neumann more t han5 0 years ago. However, t hereh as never been aphysical implementation of his universalconstructor architectureas a robotic system.Prior too ur other recent work,a nautonomous self-replicating mechanical s ystem hadn ot been developed. In t his paper, w ed emonstrateanon-von-Neumann architecturef or the replication of transistor circuits by active self-inspection. That is, therearen oi nstructions stored about how toconstruct the circuit,b ut information observed about the spatial organization of the originalcircuit drives alarger electromechanical( robotic) system in whichi t is embedded tocause the production of a replica of the originalcircuit.In the workp resented here,only replication of the control circuit is of interest.In the current context, the electromechanicalh ardwarei s viewed as a tool whichi s manipulated by the control circuit for its own reproduction.This architecturalp aradigm is demonstrated with prototypes that are reviewed hereand compared withani mplementation of the universal constructor concept. 1Introduction 1.1Motivation The concept of man-made self-replicatingmachines was first proposed by John von Neumann more thanf ifty years ag

    Measurement and Analysis of the Field Quality of LHC Prototype and Pre-series Superconducting Dipoles

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    We report the main results of the magnetic field measurements performed on the full-size LHC superconducting dipoles tested at CERN since summer 1998. Main field strength and field errors are summarised. We discuss in detail the contributions related to the geometry of the collared coil, the assembled cold mass, cool-down effects, magnetisation of the superconducting cable and saturation effects at high field. Dynamic effects on field harmonics, such as the field decay during injection and field errors during current ramps, are assessed statistically

    Correlated two-pion exchange and large-N(C) behavior of nuclear forces

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    The effect of correlated scalar-isoscalar two-pion exchange (CrTPE) modes is considered in connection with central and spin-orbit parts of the NN force. The two-pion correlation function is coupled directly to the scalar form factor of the nucleon which we calculate in the large-N(C) limit where the nucleon can be described as a soliton of an effective chiral theory. The results for the central NN force show a strong repulsive core at short internucleon distances supplemented by a moderate attraction beyond 1 fm. The long-range tail of the central NN potential is driven by the the pion-nucleon sigma term and consistent with the effective σ\sigma meson exchange. The spin-orbit part of the NN potential is repulsive. The large-N(C) scaling behavior of the scalar-isoscalar NN interaction is addressed. We show that the spin-orbit part is O(1/N^2(C)) in strength relative to the central force resulting in the ratio ≃1/9\simeq 1/9 suggested by the 1/N(C) expansion for N(C)=3. The latter is in agreement with our numerical analysis and with the Kaplan-Manohar large-N(C) power counting. Unitarization of the ππ\pi \pi scattering amplitude plays here an important role and improves the tree level results. Analytical representations of the CrTPE NN potential in terms of elementary functions are derived and their chiral content is discussed.Comment: 29 pages, 7 figure

    Graphene transistors are insensitive to pH changes in solution

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    We observe very small gate-voltage shifts in the transfer characteristic of as-prepared graphene field-effect transistors (GFETs) when the pH of the buffer is changed. This observation is in strong contrast to Si-based ion-sensitive FETs. The low gate-shift of a GFET can be further reduced if the graphene surface is covered with a hydrophobic fluorobenzene layer. If a thin Al-oxide layer is applied instead, the opposite happens. This suggests that clean graphene does not sense the chemical potential of protons. A GFET can therefore be used as a reference electrode in an aqueous electrolyte. Our finding sheds light on the large variety of pH-induced gate shifts that have been published for GFETs in the recent literature

    Proceso gerencial para la ejecuci?n del proyecto de dise?o y construcci?n de m?dulos habitacionales para estudiantes de educaci?n superior en la ciudad de Girardot

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    126 P?ginasRecurso Electr?nicoEl acceso a la educaci?n superior para los j?venes en Colombia es mayor que hace una d?cada, la competitividad y profesionalizaci?n de la mano de obra del pa?s ha generado la necesidad de la realizaci?n de estudios posteriores al bachillerato e incluso del aumento en la demanda de estudios de postgrado. Es importante citar que el Municipio de Girardot es el principal centro urbano de la regi?n, el cual aglutina la mayor poblaci?n de estudiantes de educaci?n superior, con amplia oferta de instituciones educativas, tanto p?blicas como privadas que ofrecen carreras t?cnicas, tecnol?gicas y profesionales, haciendo de ?sta una opci?n atractiva para los futuros bachilleres de las poblaciones aleda?as y propias de la ciudad. El objetivo del presente proyecto, es el dise?o, ejecuci?n y adecuaci?n de dos m?dulos habitacionales para estudiantes de educaci?n superior, donde encuentren satisfacci?n a sus necesidades de vivienda. No se pretende un modelo solamente habitacional, sino un modelo de mejoramiento de entorno, motivando el desarrollo de una metr?poli universitaria que crece cada d?a con estudiantes for?neos, por lo que se requiere tener en cuenta que el h?bitat a ofrecerles se deben reducir las condiciones carentes, y limitantes que se encuentran en la oferta habitacional actual. Se establecen resultados y entregables como son el presupuesto, plan de inversi?n, cronogramas, plan de manejo ambiental y de riesgos y los recursos necesarios para el logro de los objetivos propuestos, as? mismo se plasman en este documento todas las etapas conformadas en la ejecuci?n del proyecto.ABSTRACT The acces to higher education to young people in Colombia is bigger than a decade ago, the competitiveness y profesionalization of manpower in the country has generate the needing of realization of posterior studies to high school and even the rise on demand of postgrade studies. It is important to quote that the municipality of Girardot is the principal urban center in the region, which has the most student population of higher education, with a wide offert of educational institutes, public and private that offers technincal, technological and profesional careers, making it an atractive option to the next high school graduates of the around and of the city. The target of the present project, is the design, execution and adequacy of two housing modules to higher education student, where they can find satisfaction to them house needs. The idea is not just to make an housing model, is to make a model of improving of the environment, motivating the development of a universitary metropoli that grows up every day with foreign students, thats why it requires to realize that the in habitat to offer, should be reduced the lacking conditions and limiting that we can find in the housing offer in present. Results will be setted and appendages as the budget, investment plan, schedule, environmental management plan and risks, and the necessary resources to the achievement of the objectives, and all the stages of the project execution will be displayed.INTRODUCCI?N 17 1. DEFINICI?N Y PLANTEAMIENTO DEL PROBLEMA 18 2. JUSTIFICACI?N 19 3. OBJETIVOS 20 3.1. OBJETIVO GENERAL 20 3.2. OBJETIVOS ESPEC?FICOS 20 4. METODOLOG?A 21 5. DESCRIPCI?N GENERAL DEL PROYECTO 24 5.1. T?TULO O NOMBRE DEL PROYECTO 24 5.2. ENTIDADES RESPONSABLES O FORMULADORES 24 5.3. NECESIDADES QUE ORIGINA EL PROYECTO 24 5.4. SOLUCI?N A LA NECESIDAD 24 5.5. VIABILIDAD DE MERCADO 25 5.6. VIABILIDAD T?CNICA. 25 5.7. VIABILIDAD ADMINISTRATIVA Y LEGAL 26 5.8. VIABILIDAD AMBIENTAL 27 5.9. EVALUACI?N FINANCIERA Y ECON?MICA 28 6. EL CONTEXTO DEL PROYECTO 29 6.1. ENTORNO ECON?MICO Y FINANCIERO 29 6.1.1. Producto interno bruto 29 6.1.2. Inflaci?n 29 6.1.3. Tasa de Inter?s 29 6.1.4. An?lisis de variables 30 6.1.5. Valor presente neto (VPN) 30 6.1.6. Tasa interna de retorno (TIR) 30 6.1.7. Relaci?n beneficio ? Costo RBC 31 6.1.8. Periodo de recuperaci?n de la inversi?n 31 6.2. ENTORNO TECNOL?GICO 31 6.2.1. Conectividad y comunicaciones 31 6.3. ENTORNO POL?TICO 32 6.4. ENTORNO AMBIENTAL 32 6.5. ENTORNO SOCIAL 33 7. EL TALENTO HUMANO Y SU PAPEL PROTAG?NICO EN LA GERENCIA DEL PROYECTO 34 7.1. LA ESTRUCTURA ORGANIZACIONAL PARA LA EJECUCI?N DEL PROYECTO 34 7.2. PROCESOS DE SELECCI?N DEL GERENTE DE PROYECTO Y SU EQUIPO NUCLEAR 34 7.2.1. Proceso de selecci?n del gerente de proyectos 35 7.2.1.1. Reclutamiento 35 7.2.1.2. Selecci?n de personal 35 7.2.1.3. Ficha t?cnica Profesiogr?fica 36 7.2.2. Proceso de selecci?n del equipo nuclear 36 7.2.2.1. Reclutamiento y selecci?n de personal 36 7.2.2.2. Ficha t?cnica Profesiogr?fica 36 7.2.3. Calificaci?n 37 7.2.4. Contrataci?n 40 7.3. MODELO GERENCIAL APLICADO A LA EJECUCI?N DEL PROYECTO 41 7.3.1. Caracter?sticas de la APO 42 7.3.2. Como aplicaremos la APO 43 7.3.3. Estilo de liderazgo 43 7.4. ESTRATEGIA PARA GERENCIAR EL TALENTO HUMANO RESPONSABLE DE LA EJECUCI?N DEL PROYECTO 44 7.5. EL SISTEMA DE INFORMACI?N Y COMUNICACI?N PARA LA EJECUCI?N DEL PROYECTO 45 7.5.1. Informaci?n general del proyecto 45 7.5.2. Prop?sitos 45 7.5.3. Procedimientos acordados para la etapa de ejecuci?n 45 7.5.3.1. Procedimiento de selecci?n de outsourcing 45 7.5.3.2. Procedimiento de selecci?n gerente de proyectos y equipo nuclear 46 7.5.4. Sistema de comunicaci?n 46 7.5.4.1. Planificaci?n de la informaci?n 46 9 7.5.4.2. Difusi?n de la informaci?n (tecnolog?a) 47 7.5.5. Informes 47 7.5.6. Cierre administrativo 48 7.5.7. Reportes de desempe?o 48 7.5.7.1. Formatos 48 8. LA GERENCIA DEL PROYECTO 49 8.1. INICIO 49 8.2. PLANIFICACI?N 49 8.2.1. Objetivos generales de la ejecuci?n 49 8.2.2. Objetivos espec?ficos de la ejecuci?n 49 8.3. GESTI?N DEL ALCANCE 50 8.3.1. Acta de constituci?n del proyecto 50 8.3.2. Estructura de divisi?n del trabajo (EDT) 50 8.3.3. Descripci?n de actividades 50 8.3.4. Matriz de responsabilidades 50 8.4. GESTI?N DEL TIEMPO 50 8.4.1. Duraci?n de Actividades 50 8.4.2. Matriz de precedencias 51 8.4.3. Programa para la ejecuci?n del proyecto 52 8.4.4. Matriz de programaci?n 53 8.4.5. Red del Proyecto- Red y Gantt de la ejecuci?n del proyecto 53 8.4.6. Ruta cr?tica 54 8.4.7. Diagrama de Gantt 54 8.5. GESTI?N DEL COSTO 54 8.5.1. Inversiones fijas 54 8.5.2. Inversiones diferidas 55 8.5.3. Costo por actividades - estructura de costos 56 8.5.4. Descripci?n del flujo de caja de la ejecuci?n 60 8.5.5. Plan de desembolsos 60 8.5.5.1. Plan de desembolsos outsourcing de dise?o 60 8.5.5.2. Plan de desembolsos outsourcing de construcci?n 61 8.5.5.3. Estimaci?n de costos 62 8.5.5.4. Factores tenidos en cuenta para la estimaci?n de costos 63 8.6. GESTI?N DE RIESGO 63 8.6.1. Identificaci?n de riesgos 63 8.6.2. Clasificaci?n delos riesgos externos 64 8.6.2.1. Ambiente general 64 8.6.2.2. Ambiente sectorial o industrial 64 8.6.3. Clasificaci?n delos riesgos internos 66 8.6.3.1. Recursos y capacidades directivos 66 8.6.3.2. Recursos y capacidades financieros 67 8.6.3.3. Desconfianza con los trabajadores del proyecto 67 11 8.7. CONTROL 68 8.7.1. Reuniones semanales de evaluaci?n 69 8.7.2. Reuniones extraordinarias 69 8.7.3. Medici?n de los tiempos y costos de actividades 70 8.7.4. Lista de seguimiento de actividades y responsables 70 8.8. CIERRE 70 8.8.1. Acta de terminaci?n 70 8.8.2. Actas de liquidaci?n 70 8.9. APLICACI?N DEL PROJECT 71 9. CONTRATACI?N PARA LA EJECUCI?N DEL PROYECTO 72 9.1. CONTRATACI?N DEL GERENTE DEL PROYECTO 72 9.1.1. Contrataci?n del equipo nuclear 72 9.1.2. Contrato de Prestaci?n de Servicios 72 9.1.3. Contrato a t?rmino fijo 72 9.1.4. Contrato de outsourcing de Dise?o y construcci?n 72 10. CONCLUSIONES 73 11. RECOMENDACIONES 74 REFERENCIAS 75 ANEXOS 7

    Facilitating motor imagery-based brain–computer interface for stroke patients using passive movement

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    Motor imagery-based brain–computer interface (MI-BCI) has been proposed as a rehabilitation tool to facilitate motor recovery in stroke. However, the calibration of a BCI system is a time-consuming and fatiguing process for stroke patients, which leaves reduced time for actual therapeutic interaction. Studies have shown that passive movement (PM) (i.e., the execution of a movement by an external agency without any voluntary motions) and motor imagery (MI) (i.e., the mental rehearsal of a movement without any activation of the muscles) induce similar EEG patterns over the motor cortex. Since performing PM is less fatiguing for the patients, this paper investigates the effectiveness of calibrating MI-BCIs from PM for stroke subjects in terms of classification accuracy. For this purpose, a new adaptive algorithm called filter bank data space adaptation (FB-DSA) is proposed. The FB-DSA algorithm linearly transforms the band-pass-filtered MI data such that the distribution difference between the MI and PM data is minimized. The effectiveness of the proposed algorithm is evaluated by an offline study on data collected from 16 healthy subjects and 6 stroke patients. The results show that the proposed FB-DSA algorithm significantly improved the classification accuracies of the PM and MI calibrated models (p < 0.05). According to the obtained classification accuracies, the PM calibrated models that were adapted using the proposed FB-DSA algorithm outperformed the MI calibrated models by an average of 2.3 and 4.5 % for the healthy and stroke subjects respectively. In addition, our results suggest that the disparity between MI and PM could be stronger in the stroke patients compared to the healthy subjects, and there would be thus an increased need to use the proposed FB-DSA algorithm in BCI-based stroke rehabilitation calibrated from PM

    Modes of Foreign Entry under Asymmetric Information about Potential Technology Spillovers

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    This paper studies the effect of technology spillovers on the entry decision of a multinational enterprise into a foreign market. Two alternative entry modes for a foreign direct investment are considered: Greenfield investment versus acquisition. We find that with quantity competition a spillover makes acquisitions less attractive, while with price competition acquisitions become more attractive. Asymmetric information about potential spillovers always reduces the number of acquisitions independently of whether the host country or the entrant has private information. Interestingly, we find that asymmetric information always hurts the entrant, while it sometimes is in favor of the host country
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