A linear acoustic model for multi-cylinder IC engine intake manifolds including the effects of the intake throttle

This paper presents a linear acoustic model of a multi-cylinder intake manifold that can be used as part of a hybrid time/frequency domain method to calculate the intake wave dynamics of practical naturally aspirated engines. The method allows the user to construct a model of almost any manifold of complex geometry. The model is constructed as an assemblage of sub-models: (i) A model for a straight pipe with both ends open and through-flow. (ii) A model for an expansion chamber consisting of three lengths of pipe laid end-to-end: a narrow bore pipe expanding into a wide bore pipe contracting into a narrower bore pipe once more. (iii) A model of a side-branch, which includes a model for a straight pipe with one end closed and a model for the three way junction that joins the side-branch to a length of flow pipe. (iv) A model for an expansion with two (or more) side-branches, which combines the sub-models (i, ii, iii) into a multi-way (n-way) junction model. (v) A model for an intake throttle. Good agreement with measurement has been found for each sub-model when bench-tested in isolation and encouraging agreement has been found when many sub-models are used together to model a complex intake manifold on a running engine

The Hotelling's Rule Revisited in a Dynamic General Equilibrium Model

The validity of the Hotelling?s rule, the fundamental theorem of nonrenewable resource eco- nomics, is limited by its partial equilibrium nature. One symptom of this limitation may be the disagreement between the empirical evidence, showing stable or declining resource prices, and the rule, predicting exponentially increasing prices. In this paper, we study the optimal depletion of a nonrenewable resource in a dynamic general equilibrium framework.We show that in, the long run, the price of a nonrenewable (i) is constant when the nonrenewable is essential in production, and (ii) it increases only if the rate of return of capital is larger than the capital depreciation rate and if the non-renewable is an inessential input in production. We believe that our model offers a theoretical explanation to non-growing nonrenewable prices and hence at least partially solves the paradox between the Hotelling's rule and the empirical regularities. We also show that two factors play a crucial role in determining the long run behavior of non-renewable prices, namely the elasticity of substitution between input factors, and the long run behavior of the real interest rate. Another major achievement of this study is the full analytical solution of the model under a Cobb-Douglas technology.Nonrenewable resources; One-sector growth model, Hotelling?s Rule, Sustainability

Mineralogical analysis of mortars in the walls of Ávila (Spain) and its surroundings

The present article evaluated the mineralogical composition of 85 mortar samples from some emblematic monuments of Ávila city (Spain), which were collected during the restoration of the monuments. The aim of this article is to try to extract the relationship between the composition and the origin of the raw materials, as well as to identify possible alterations in the samples. The study of the samples was carried out using visual and petrographic techniques such as stereoscopic microscope, XRD, and SEM/EDX analysis. The main components of the mortars were calcite, feldspar and quartz, although small amounts of phyllosilicates were also identified. The minerals of the mortars came from the surroundings of the city, and some of the samples presented evident alteration of the original materials due to humidity, salt concentration, and biological weathering, possibly inducted by unfortunate effects of the restoration. Finally, a study of the salts present in some mortars showed that most samples display contamination of soluble salts such as halite, thenardite, hexaedrite, and carnalite. This investigation offers fresh insight into historic building activity and related techniques, and should provide knowledge useful for restoration and conservation processes

The Nuclear Yukawa Model on a Lattice

We present the results of the quantum field theory approach to nuclear Yukawa model obtained by standard lattice techniques. We have considered the simplest case of two identical fermions interacting via a scalar meson exchange. Calculations have been performed using Wilson fermions in the quenched approximation. We found the existence of a critical coupling constant above which the model cannot be numerically solved. The range of the accessible coupling constants is below the threshold value for producing two-body bound states. Two-body scattering lengths have been obtained and compared to the non relativistic results.Comment: 15 page

Orbital angular momentum from marginals of quadrature distributions

We set forth a method to analyze the orbital angular momentum of a light field. Instead of using the canonical formalism for the conjugate pair angle-angular momentum, we model this latter variable by the superposition of two independent harmonic oscillators along two orthogonal axes. By describing each oscillator by a standard Wigner function, we derive, via a consistent change of variables, a comprehensive picture of the orbital angular momentum. We compare with previous approaches and show how this method works in some relevant examples.Comment: 7 pages, 2 color figure

Joan Nunes, director del LIGIT

Joan Nunes, director del Laboratori d'Informació Geogràfica i Teledetecció de la UAB, ens ha rebut amb motiu de la celebració dels 21 anys de vida del LIGIT. Un laboratori que va començar com a recurs del Departament de Geografia i que, avui dia, ha esdevingut un fort servei de suport a la recerca i de formació professional. Per celebrar l'èxit d'aquest projecte han organitzat una setmana de portes obertes amb debats, exposicions i tallers gratuïts d'aprenentatge. A més a més, han rebut la visita de Roger Tomlinson, el pare dels Sistemes d'Informació Geogràfica (SIG), i base tecnològica del LIGIT. Amb ell han debatut els interrogants sobre el futur de la informació geoespacial

Influence of survey engagement and multiple-choice heuristics in the estimation of the value of a statistical life

Estimating the value of non-market goods, such as reductions in mortality risks due to traffic accidents or air pollution, is typically done using stated choice (SC) data. However, issues with potential estimation biases due to the hypothetical nature of SC experiments arise, as protest choices are common and survey engagement is not constant across respondents. Further, if respondents choose to use different choice mechanisms and this is not considered, the results may also be biased. We designed an SC experiment to estimate the willingness to pay (WTP) for mortality risk reductions, that allowed us to simultaneously estimate the WTP to reduce the risk of traffic accident deaths and cardiorespiratory deaths due to air pollution. We formulated and estimated a multiple heuristic latent class model that also considered two latent constructs: Institutional Belief, to consider protest responses, and survey Engagement as a class membership covariate. We found, first, that individuals with lower institutional belief gave a higher probability of choice to the status-quo alternative, shying away from programs involving governmental action. Second, that not identifying respondents who do not appropriately engage in the experiment, biased the WTP estimators. In our case WTP decreased up to 26% when two different choice heuristics were allowed for in the model. © 202

Influencia de la percepción visual del rostro del hablante en la credibilidad de su voz

Consultable des del TDXTítol obtingut de la portada digitalitzadaObjetivos del estudio: Determinar en qué medida la MODALIDAD de PERCEPCIÓN y la PERCEPCION AUDIOVISUAL influyen en la atribución de CREDIBILIDAD de los perceptores: 1) A hablantes PROFESIONALES y NO PROFESIONALES. Es decir, según sea la capacidad de generar y explotar variedades acústicas de las voces producto de su entrenamiento o experiencia; 2) Según sea el FORMATO de TEXTO interpretado por los hablantes En este sentido, utilizamos dos textos diferentes y enfrentamos la CREDIBILIDAD que obtienen los locutores cuando leen un TEXTO FORMAL, es decir, un TEXTO creado según las pautas que rigen la concepción y construcción de mensajes específicos para los medios de comunicación audiovisuales, a cuando leen un TEXTO INFORMAL, aquel que no las sigue; 3) Según sea el SEXO del HABLANTE; 4) Según sean PERCEPTORES FEMENINOS o MASCULINOS; 5) en función de la FRECUENCIA FUNDAMENTAL de las VOCES de los HABLANTES. Para ello, se trabaja con voces con FRECUENCIAS MEDIAS FUNDAMENTALES GRAVES, MEDIAS y AGUDAS; 6) Según sea la VELOCIDAD (RAPIDA, MEDIA o LENTA) de lectura de los hablante, y finalmente, nos proponemos profundizar en los aspectos que se vayan desprendiendo de la consecución de estos objetivos y de la interrelación de las variables mencionadas. Hipótesis: 1) Las características formales del TEXTO interpretado influyen en el grado de atribución de CREDIBILIDAD a los hablantes, por encima de la MODALIDAD de PERCEPCIÓN; 1.1) La interpretación de TEXTOS FORMALES, aquellos cuya estructura y contenido sigue las pautas aconsejadas para la construcción de mensajes mediáticos, permitirá la obtención de superiores grados de CREDIBILIDAD a los hablantes, que la interpretación de TEXTOS INFORMALES que no las siguen, y esto ocurrirá tanto cuando únicamente se escucha al hablante como cuando además se le VE; 2) La capacidad de generar variedades controladas de la voz influye en la atribución de CREDIBILIDAD al hablante, por encima de la MODALIDAD de PERCEPCIÓN; 2.1) Los hablantes PROFESIONALES obtendrán superiores grados de CREDIBILIDAD que los hablantes NO PROFESIONALES, tanto cuando se les escucha como cuando se les ve; 3) La capacidad de generar variedades coherentes de voz, producto del entrenamiento o la experiencia, influye por encima del FORMATO de TEXTO interpretado y de la MODALIDAD de PERCEPCIÓN; 3.1) Los hablantes PROFESIONALES resultarán más creíbles que los NO PROFESIONALES en la interpretación de cualquiera de los dos TEXTOS, el FORMAL o el INFORMAL, tanto cuando se les escucha como cuando se les ve; 4) El SEXO del HABLANTE influye en la atribución de CREDIBILIDAD de forma discriminante según sea el SEXO del PERCEPTOR y por encima de la MODALIDAD de PERCEPCIÓN. 4.1) Los hablantes MASCULINOS obtendrán superiores índices de CREDIBILIDAD que los FEMENINOS, tanto cuando se les ESCUCHA como cuando se les VE; 5) La VELOCIDAD de LECTURA influye en la atribución de CREDIBILIDAD, por encima de la MODALIDAD de PERCEPCIÓN; 5.1) Los hablantes RAPIDOS resultarán más CREÍBLES que los MEDIOS y LENTOS, tanto cuando se les ESCUCHA como cuando se les VE. 6) La FRECUENCIA MEDIA FUNDAMENTAL de las voces influye en la atribución de CREDIBILIDAD, por encima de la MODALIDAD de PERCEPCIÓN. 6.1) Los hablantes con FRECUENCIAS FUNDAMENTALES GRAVES resultarán más CREIBLES que los hablantes con FRECUENCIAS MEDIAS y AGUDAS, tanto cuando se les ESCUCHA como cuando se les VE; 7) De todo lo anterior resulta evidente que hipotetizamos que el peso de los factores acústicos primará sobre el peso de los factores visibles en la atribución de CREDIBILIDAD; 7.1) La PERCEPCIÓN AUDIOVISUAL actuará sobre los modelos de enjuiciamiento, sobre las razones por las que los perceptores atribuyen CREDIBILIDAD; 7.2) La PERCEPCION AUDIOVISUAL ocasionará que el conjunto y el peso propio de las variables que modelan la CREDIBILIDAD SONORA de los hablantes, sean diferente al conjunto y al peso propio de las variables que definen la CREDIBILIDAD AUDIOVISUAL de los hablantes.; 7.3) La PERCEPCIÓN AUDIOVISUAL de los hablantes permitirá verificar, clarificar y precisar las atribuciones de CREDIBILIDAD. Esa es la función de la PERCEPCIÓN VISUAL DEL ROSTRO DEL HABLANTE en la atribución de CREDIBILIDAD.Study Objectives: To determine the extent to which the FORM of PERCEPTION and AUDIOVISUAL PERCEPTION influence the perceiver's attribution of CREDIBILITY: 1) Between PROFESSIONAL and NON-PROFESSIONAL speakers, i.e. depending on the ability to generate and exploit acoustic voice varieties as a result of training or experience; 2) Depending on the FORMAT of the TEXT to be read by the speakers. To this effect, we used two different texts and compared the CREDIBILITY accomplished by the speakers when reading a FORMAL TEXT (i.e. a TEXT written according to the standard norms of conception and construction of specific messages for use in audiovisual communication) to when reading an INFORMAL TEXT, i.e. one that does not follow such norms; 3) Depending on the GENDER of the SPEAKER; 4) Depending on whether the PERCEIVERS are MALE or FEMALE; 5) Depending on the BASIC FREQUENCY of the VOICES of the SPEAKERS. To do this, LOW, MEDIUM and HIGH BASIC VOICE FREQUENCIES were studied; 6) Depending on the READING SPEED (FAST, MEDIUM or SLOW) of the speaker. To conclude we shall investigate further the issues that arise from the achievement of these objectives and any interrelation with the aforementioned variables. Hypothesis: 1) The formal characteristics of the TEXT to be read have a greater influence on the level of CREDIBILITY of a speaker than the FORM of PERCEPTION; 1.1) The reading of FORMAL TEXTS, those whose structure and content follow the standards recommended for the construction of media messages, gives the speaker higher levels of CREDIBILITY than the reading of INFORMAL TEXTS (which do not follow such norms), and this occurs as much when the speaker is only heard as when he or she is also seen; 2) The ability to generate controlled varieties of voice influence the CREDIBILITY of a speaker more than the FORM of PERCEPTION; 2.1) PROFESSIONAL speakers reach higher levels of CREDIBILITY than NON-PROFESSIONAL speakers; as much when they are listened to as when they are seen; 3) The ability to generate coherent varieties of voice, through training or expertise, is more influential than the FORMAT of the TEXT being read and the FORM of PERCEPTION; 3.1) PROFESSIONAL speakers will be more credible than NON-PROFESSIONALS in the reading of both the FORMAL and the INFORMAL text, both when only heard and when seen; 4) The GENDER of the SPEAKER discriminately influences CREDIBILITY depending more on the GENDER of the PERCEIVER than the FORM of PERCEPTION. 4.1) MALE speakers achieve better levels of CREDIBILITY than FEMALE ones, as much when listened to as when seen; 5) READING SPEED has a greater influence on CREDIBILITY than the FORM of PERCEPTION; 5.1) FAST speakers are more credible than MEDIUM or SLOW speakers, as much when they are LISTENED TO as when they are SEEN. 6) The BASIC MEAN FREQUENCY of voices has greater influence on CREDIBILITY than the FORM of PERCEPTION. 6.1) Speakers with LOW BASIC FREQUENCIES are more credible than speakers with MEDIUM or HIGH FREQUENCIES, as much when they are LISTENED TO as when they are SEEN; 7) In the aforementioned cases it is clear that we are hypothesizing that acoustic factors carry stronger influence than visibility factors in gaining CREDIBILITY; 7.1) AUDIOVISUAL PERCEPTION acts on judgment models, on the reasons why perceivers attribute CREDIBILITY; 7.2) AUDIOVISUAL PERCEPTION makes the grouping, and particular strengths, of the variables that model SOUND CREDIBILITY different to the group of variables, and their particular strengths, that define the AUDIOVISUAL CREDIBILITY of speakers; 7.3) The AUDIOVISUAL PERCEPTION of speakers allows for the verification, clarification and specification of attributions of CREDIBILITY. This is the function of the VISUAL PERCEPTION OF THE FACE OF THE SPEAKER in the attribution of CREDIBILITY

YOLO Object Detector for Onboard Driving Images

With the evolution of artificial intelligence and, specially, machine learning, tech and car manufacturing companies are in research of the car of the future. Along with the arrival of new powerful hardware, deep learning is expected to be one of the most outstanding fields in the automotive sector. In this paper, we will be developing an object detection system with neural networks using the You Only Look Once (YOLO) network architecture. We will train and evaluate the model using various datasets and extract conclusions on its feasibility for autonomous driving or other driving assistance applications.Con la evolución de la inteligencia artificial y, especialmente, el aprendizaje computacional, las empresas fabricantes de automóviles y de tecnología están en plena investigación del coche del futuro. Junto con la llegada de nuevo hardware potente, el aprendizaje profundo se espera que sea uno de los campos más destacados en el sector automotriz. En este trabajo, estaremos desarrollando un sistema de detección de objetos con redes neuronales utilizando la arquitectura de You Only Look Once (YOLO). Vamos a entrenar y evaluar el modelo utilizando varios conjuntos de datos y extraer conclusiones sobre su viabilidad para la conducción autónoma u otras aplicaciones de asistencia a la conducción.Amb l'evolució de la intel·ligència artificial i, especialment, l'aprenentatge computacional, les empreses fabricants d'automòbils i de tecnologia estan en plena investigació del cotxe del futur. Juntament amb l'arribada de nou maquinari potent, l'aprenentatge profund s'espera que sigui un dels camps més destacats en el sector de l'automòbil. En aquest treball, estarem desenvolupant un sistema de detecció d'objectes amb xarxes neuronals utilitzant l'arquitectura de You Only Look Onze (YOLO). Entrenarem i avaluarem el model utilitzant diversos conjunts de dades per poder extreure conclusions sobre la seva viabilitat per a la conducció autònoma o altres aplicacions d'assistència a la conducció

Generalized Casimir forces in non-equilibrium systems

In the present work we propose a method to determine fluctuation induced forces in non equilibrium systems. These forces are the analogue of the well known Casimir forces, which were originally introduced in Quantum Field theory and later extended to the area of Critical Phenomena. The procedure starts from the observation that many non equilibrium systems exhibit long-range correlations and the associated structure factors diverge in the long wavelength limit. The introduction of external bodies into such systems in general modifies the spectrum of these fluctuations and leads to the appearance of a net force between these bodies. The mechanism is illustrated by means of a simple example: a reaction diffusion equation with random noises.Comment: Submitted to Europhysics Letters. 7 pages, 2 figure