Energy efficiency in discrete-manufacturing systems: insights, trends, and control strategies

Since the depletion of fossil energy sources, rising energy prices, and governmental regulation restrictions, the current manufacturing industry is shifting towards more efficient and sustainable systems. This transformation has promoted the identification of energy saving opportunities and the development of new technologies and strategies oriented to improve the energy efficiency of such systems. This paper outlines and discusses most of the research reported during the last decade regarding energy efficiency in manufacturing systems, the current technologies and strategies to improve that efficiency, identifying and remarking those related to the design of management/control strategies. Based on this fact, this paper aims to provide a review of strategies for reducing energy consumption and optimizing the use of resources within a plant into the context of discrete manufacturing. The review performed concerning the current context of manufacturing systems, control systems implemented, and their transformation towards Industry 4.0 might be useful in both the academic and industrial dimension to identify trends and critical points and suggest further research lines.Peer ReviewedPreprin

Estudio sobre la construcción bioclimática : diseño, materiales de construcción e instalaciones

Trabajo científico técnico. Este proyecto parte de la premisa de que la calidad en la edificación es la clave para relanzar el mercado, mejorar las condiciones medioambientales y ahorrar recursos energéticos. Esta visión incluye tanto los materiales, como los sistemas o estrategias constructivos, como las instalaciones. Todo esto lo tiene en cuenta la construcción Bioclimática.Martínez Giménez, L. (2011). Estudio sobre la construcción bioclimática : diseño, materiales de construcción e instalaciones. http://hdl.handle.net/10251/12082.Archivo delegad

Real divergences and the eurozone crisis

Treball Final de Grau en Economia. Codi: EC1049. Curs acadèmic 2013-2014The first 15 years of European Monetary Union (EMU) have seen growing structural imbalances between member states without offsetting gains in productivity and economic growth. Economic tensions within the Eurozone have been building since its inception, and have become acute during the current crisis. It has created a dualism in the euro zone, with northern countries recovering, albeit slowly, from the crisis, increasingly diverging from southern countries that are embroiled in sovereign-debt crises and with weak prospects of growth, even in the medium term. Divergence in competitiveness, in current accounts and in private sector debts has led to excessive public sector debt and deficits in peripheral Southern countries. The Eurozone has imposed an asymmetric policy response to these divergences, with the burden of adjustment falling almost exclusively on the weaker economies of the South. These peripheral economies are required to seek a real depreciation with respect to the North through a combination of wage reductions and fiscal retrenchment. But, will the internal devaluation contribute to a further increase of real divergences or to restore competitiveness in the peripheral countries? This is the primarily question of this proposal. It is aimed to analyze the euro crisis, focusing on its economic roots and the interactions between the crisis and the observed real divergences. The results suggest that there are notable differences across countries and the whole nation in terms of capital intensity and total factor productivity. Furthermore, the economic reforms don’t have been successful in driving long-run growth. So, countries need further reforms in order to reach convergence

Biopolítica y género : el caso de China

La biopolítica y el género son dos conceptos perfectamente aplicables a las sociedades actuales en las que el poder sigue ejerciendo un control de los cuerpos en función de sus intereses. China es un claro ejemplo de la vigencia de esta forma de opresión que se ejerce principalmente sobre los cuerpos femeninos. Dados los beneficios que la industria cosmética y la industria sexual están aportando a las arcas nacionales Chinas, el modelo de feminidad está cambiando para servir a los intereses del mercado. Los medios de comunicación son los principales creadores de una identidad femenina basada en el culto al cuerpo y en el retorno de valores de la feminidad tradicional que se creían superados. Esta nueva tendencia funciona como un mecanismo de control realmente eficaz que centra los intereses y las preocupaciones de las mujeres únicamente en la estética para frenar su posible potencial de lucha por conseguir la liberación y la igualdad real. Al asociar el ideal de belleza con el placer sexual, la aceptación por parte de las mujeres es mucho mayor, y por tanto se consigue penetrar en sus mentes y modificar el imaginario colectivo para generar en las mujeres una sensación de empoderamiento y libertad poco homologable con la realidad

Channel Estimation Architectures for Mobile Reception in Emerging DVB Standards

Throughout this work, channel estimation techniques have been analyzed and proposed for moderate and very high mobility DVB (digital video broadcasting) receivers, focusing on the DVB-T2 (Digital Video Broadcasting - Terrestrial 2) framework and the forthcoming DVB-NGH (Digital Video Broadcasting - Next Generation Handheld) standard. Mobility support is one of the key features of these DVB specifications, which try to deal with the challenge of enabling HDTV (high definition television) delivery at high vehicular speed. In high-mobility scenarios, the channel response varies within an OFDM (orthogonal frequency-division multiplexing) block and the subcarriers are no longer orthogonal, which leads to the so-called ICI (inter-carrier interference), making the system performance drop severely. Therefore, in order to successfully decode the transmitted data, ICI-aware detectors are necessary and accurate CSI (channel state information), including the ICI terms, is required at the receiver. With the aim of reducing the number of parameters required for such channel estimation while ensuring accurate CSI, BEM (basis expansion model) techniques have been analyzed and proposed for the high-mobility DVB-T2 scenario. A suitable clustered pilot structure has been proposed and its performance has been compared to the pilot patterns proposed in the standard. Different reception schemes that effectively cancel ICI in combination with BEM channel estimation have been proposed, including a Turbo scheme that includes a BP (belief propagation) based ICI canceler, a soft-input decision-directed BEM channel estimator and the LDPC (low-density parity check) decoder. Numerical results have been presented for the most common channel models, showing that the proposed receiver schemes allow good reception, even in receivers with extremely high mobility (up to 0.5 of normalized Doppler frequency).Doktoretza tesi honetan, hainbat kanal estimazio teknika ezberdin aztertu eta proposatu dira mugikortasun ertain eta handiko DVB (Digital Video Broadcasting) hartzaileentzat, bigarren belaunaldiko Lurreko Telebista Digitalean DVB-T2 (Digital Video Broadcasting - Terrestrial 2 ) eta hurrengo DVB-NGH (Digital Video Broadcasting - Next Generation Handheld) estandarretan oinarrututa. Mugikortasuna bigarren belaunaldiko telebista estandarrean funtsezko ezaugarri bat da, HDTV (high definition television) zerbitzuak abiadura handiko hartzaileetan ahalbidetzeko erronkari aurre egiteko nahian. Baldintza horietan, kanala OFDM (ortogonalak maiztasun-zatiketa multiplexing ) sinbolo baten barruan aldatzen da, eta subportadorak jada ez dira ortogonalak, ICI-a (inter-carrier interference) sortuz, eta sistemaren errendimendua hondatuz. Beraz, transmititutako datuak behar bezala deskodeatzeko, ICI-a ekiditeko gai diren detektagailuak eta CSI-a (channel state information) zehatza, ICI osagaiak barne, ezinbestekoak egiten dira hartzailean. Kanalaren estimazio horretarako beharrezkoak diren parametro kopurua murrizteko eta aldi berean CSI zehatza bermatzeko, BEM (basis expansion model) teknika aztertu eta proposatu da ICI kanala identifikatzeko mugikortasun handiko DVB-T2 eszenatokitan. Horrez gain, pilotu egitura egokia proposatu da, estandarrean proposatutako pilotu ereduekin alderatuz BEM estimazioan oinarritua. ICI-a baliogabetzen duten hartzaile sistema ezberdin proposatu dira, Turbo sistema barne, non BP (belief propagation) detektagailua, soft BEM estimazioa eta LDPC (low-density parity check ) deskodetzailea uztartzen diren. Ohiko kanal ereduak erabilita, simulazio emaitzak aurkeztu dira, proposatutako hartzaile sistemak mugikortasun handiko kasuetan harrera ona dutela erakutsiz, 0.5 Doppler maiztasun normalizaturaino.Esta tesis doctoral analiza y propone diferentes técnicas de estimación de canal para receptores DVB (Digital Video Broadcasting) con movilidad moderada y alta, centrándose en el estándar de segunda generación DVB-T2 (Digital Video Broadcasting - Terrestrial 2 ) y en el próximó estándar DVB-NGH (Digital Video Broadcasting - Next Generation Handheld ). La movilidad es una de las principales claves de estas especificaciones, que tratan de lidiar con el reto de permitir la recepción de señal HDTV (high definition television) en receptores móviles. En escenarios de alta movilidad, la respuesta del canal varía dentro de un símbolo OFDM (orthogonal frequency-division multiplexing ) y las subportadoras ya no son ortogonales, lo que genera la llamada ICI (inter-carrier interference), deteriorando el rendimiento de los receptores severamente. Por lo tanto, con el fin de decodificar correctamente los datos transmitidos, detectores capaces de suprimir la ICI y una precisa CSI (channel state information), incluyendo los términos de ICI, son necesarios en el receptor. Con el objetivo de reducir el número de parámetros necesarios para dicha estimación de canal, y al mismo tiempo garantizar una CSI precisa, la técnica de estimación BEM (basis expansion model) ha sido analizada y propuesta para identificar el canal con ICI en receptores DVB-T2 de alta movilidad. Además se ha propuesto una estructura de pilotos basada en clústers, comparando su rendimiento con los patrones de pilotos establecidos en el estándar. Se han propuesto diferentes sistemas de recepción que cancelan ICI en combinación con la estimación BEM, incluyendo un esquema Turbo que incluye un detector BP (belief propagation), un estimador BEM soft y un decodificador LDPC (low-density parity check). Se han presentado resultados numéricos para los modelos de canal más comunes, demostrando que los sistemas de recepción propuestos permiten la decodificación correcta de la señal incluso en receptores con movilidad muy alta (hasta 0,5 de frecuencia de Doppler normalizada)

La hetera, ¿buena o mala? Un personaje secundario en el punto de mira de la comedia griega

La hetera es un personaje de la Comedia griega generalmente secundario que es explotado de forma más o menos generosa a lo largo de la historia de este género literario. Sin embargo, esta explotación es un tanto ambigua, ya que tan pronto la hetera es tratada generosa y positivamente, después es vituperada y caricaturizada como un gran mal para el hombre. En este último punto veríamos la herencia de concepciones misóginas tradicionales, que los poetas de la Comedia saben reflejar de manera abundante: la hetera es caprichosa, capciosa, taimada, un ser que tan solo se preocupa por su aspecto y por sacar hasta la última moneda de sus víctimas. Por otra parte, a pesar de aquellos títulos en los que la hetera prácticamente lleva la voz cantante en el desarrollo de la trama, examinaremos esta figura desde el punto de vista de su participación secundaria en la acción, haciendo un repaso a su configuración y tratamiento en las diversas fases de la Comedia griega. El principal objetivo es discernir cuáles son los diferentes roles que desarrolla la hetera a lo largo de estas fases, cómo y en qué circunstancias la retratan los poetas cómicos y, sobre todo, cuál es su importancia en el desarrollo de la trama y la historia que se esconde tras este característico tipo cómico, que tenía su auténtico correlato en la sociedad ateniense.The hetaera is normally a secondary character of the Greek Comedy which is more or less exploited along the history of this literary genre. However, this exploitation is few ambiguous, because when the hetaera is treated generously and positively, suddenly is censured and caricaturized like a great misfortune for man. In this last fact we would see the legacy of traditional misogynist ideas, which the comic poets know to reflect abundantly: the hetaera is whimsical, tricky, cunning, a being that only cares about their appearance and the extraction of their victims’s last penny. On the other hand, in spite of the titles of comedies where the hetaera is the most important character, we will examine the hetaera from the point of view of her secondary participation in the development of the plot, making a review of its configuration and treatment in the various phases of Greek Comedy. The principal objective is the discernment of the different roles that the hetaera develops along these phases, the nature of the circumstances in which comic poets portray the hetaera, and especially its importance in the development of the plot and the story behind this characteristic comic character, which had its counterpart in Athenian society

La Agathonszene: una teoría poética en Tesmoforiantes de Aristófanes

La escena en que el tragico Agaton hace su aparicion dentro de las Tesmoforiantes de Aristofanes (vv. 95-265) no ha pasado desapercibida para los estudiosos por diversas cuestiones. El presente articulo pretende indagar en dichas cuestiones, destacando la teoria de la 'Ê.'Ê'Å'Ð'Ç. que viene enunciada en este pasaje y que es el primer testimonio en la literatura en que aparece formulada manifiestamente. Ademas, se insiste tambien en el motivo de las innovaciones musicales que introdujeron las nuevas generaciones de poetas y que la Comedia Antigua observaba no sin preocupacion y chanza.The scene in which the tragic Agathon comes on stage in Aristophanes'f Thesmophoriazusae (vv. 95-265) has not gone unnoticed by scholars for several reasons. This article investigates these issues and highlights the 'Ê.'Ê'Å'Ð'Ç. theory that is for the first time explicitly formulated in this passage. Furthermore, I shall also emphasize the musical innovations introduced by new generations of poets and considered with concern and derision by Old Comedy

Economic model predictive control for optimal operation of combined heat and power systems

© 2019. ElsevierThe use of decentralized Combined Heat and Power (CHP) plants is increasing since the high levels of efficiency they can achieve. Hence, to determine the optimal operation of these systems in the changing energy market, the time-varying price profiles for both electricity as well as the required resources and the energy-market constraints should be considered into the design of the control strategies. To solve these issues and maximize the profit during the operation of the CHP plant, this paper proposes an optimization-based controller, which will be designed according to the Economic Model Predictive Control (EMPC) approach. The proposed controller is designed considering a non-constant time step to get a high sampling frequency for the near instants and a lower resolution for the far instants. Besides, a soft constraint to met the market constraints for the sale of electric power is proposed. The proposed controller is developed based on a real CHP plant installed in the ETA research factory in Darmstadt, Germany. Simulation results show that lower computational time can be achieved if a non-constant step time is implemented while the market constraints are satisfied.Peer ReviewedPostprint (author's final draft

Optimal operation of combined heat and power systems: an optimization-based control strategy

The use of decentralized Combined Heat and Power (CHP) plants is increasing since the high levels of efficiency they can achieve. Thus, to determine the optimal operation of these systems in dynamic energy-market scenarios, operational constraints and the time-varying price profiles for both electricity and the required resources should be taken into account. In order to maximize the profit during the operation of the CHP plant, this paper proposes an optimization-based controller designed according to the Economic Model Predictive Control (EMPC) approach, which uses a non-constant time step along the prediction horizon to get a shorter step size at the beginning of that horizon while a lower resolution for the far instants. Besides, a softening of related constraints to meet the market requirements related to the sale of electric power to the grid point is proposed. Simulation results show that the computational burden to solve optimization problems in real time is reduced while minimizing operational costs and satisfying the market constraints. The proposed controller is developed based on a real CHP plant installed at the ETA research factory in Darmstadt, Germany.Peer ReviewedPostprint (author's final draft