Space-time coding techniques are widely used in multiple-input multiple-output communication systems to mitigate the effect of multipath fading in wireless channels. An important subset of space-time codes are linear dispersion (LD) codes, which are used for quasi-static Rayleigh flat fading channels when the channel state information (CSI) is only available at the receiver side. In this thesis, we propose a new receiver structure for LD codes. We suggest to use widely-linear minimum-mean-squared-error (WL-MMSE) estimates of the transmitted symbols in lieu of the sufficient statistics for maximum likelihood (ML) detection of these symbols. This structure offers both optimal and suboptimal operation modes. The structures of the proposed receivers in both modes are derived for general LD codes. As special cases, we study two important subsets of LD codes, namely orthogonal and quasi-orthogonal codes, and examine the performance of the proposed receivers for these codes.

The scarce and overpopulated radio spectrum is going to present a major barrier to the growth and development of future wireless networks. As such, spectrum sharing seems to be inevitable to accommodate the exploding demand for high data rate applications. A major challenge to realizing the potential advantages of spectrum sharing is interference management. This thesis deals with interference management techniques in noncooperative networks. In specific, interference alignment is used as a powerful technique for interference management. We use the degrees of freedom (DoF) as the figure of merit to evaluate the performance improvement due to the interference management schemes. This dissertation is organized in two parts. In the first part, we consider the K-user multiple input multiple output (MIMO) Gaussian interference channel (IC) with M antennas at each transmitter and N antennas at each receiver. This channel models the interaction between K transmitter-receiver pairs sharing the same spectrum for data communication. It is assumed that the channel coefficients are constant and are available at all nodes prior to data transmission. A new cooperative upper-bound on the DoF of this channel is developed which outperforms the known bounds. Also, a new achievable transmission scheme is provided based on the idea of interference alignment. It is shown that the achievable DoF meets the upper-bound when the number of users is greater than a certain threshold, and thus it reveals the channel DoF. In the second part, we consider communication over MIMO interference and X channels in a fast fading environment. It is assumed that the transmitters obtain the channel state information (CSI) after a finite delay which is greater than the coherence time of the channel. In other words, the CSI at the transmitters becomes outdated prior to being exploited for the current transmission. New transmission schemes are proposed which exploit the knowledge of the past CSI at the transmitters to retrospectively align interference in the subsequent channel uses. The proposed transmission schemes offer DoF gain compared to having no CSI at transmitters. The achievable DoF results are the best known results for these channels. Simple cooperative upper-bounds are developed to prove the tightness of our achievable results for some network configurations.

This thesis is concerned with input-output stability theory. Within this framework, it is of interest how inputs map to outputs through an operator that represents a system to be controlled or the controller itself. The Small Gain, Passivity, and Conic Sector Stability Theorems can be used to assess the stability of a negative feedback interconnection involving two systems that each have specific input-output properties. Our first contribution concerns characterization of the input-output properties of linear time-varying (LTV) systems. We present various theorems that ensure that a LTV system has finite gain, is passive, or is conic. We also consider the stability of various negative feedback interconnections. Motivated by the robust nature of passivity-based control, we consider how to overcome passivity violations. This investigation leads to the hybrid conic systems framework whereby systems are described in terms of multiple conic bounds over different operating ranges. A special case relevant to systems that experience a passivity violation is the hybrid passive/finite gain framework. Sufficient conditions are derived that ensure the negative feedback interconnection of two hybrid conic systems is stable. The input-output properties of gain-scheduled systems are also investigated. We show that a gain-scheduled system composed of conic subsystems has conic bounds as well. Using the conic bounds of the subsystems along with the scheduling signal properties, the overall conic bounds of the gain-scheduled system can be calculated. We also show that when hybrid very strictly passive/finite gain (VSP/finite gain) subsystems are gain-scheduled, the overall map is also hybrid VSP/finite gain. Being concerned with the control of aerospace systems, we use the theory developed in this thesis to control two interesting plants. We consider passivity-based control of a spacecraft endowed with magnetic torque rods and reaction wheels. In particular, we synthesize a LTV input strictly passive controller. Using hybrid theory we control single- and two-link flexible manipulators. We present two controller synthesis schemes, each of which employs numerical optimization techniques and attempts to have the hybrid VSP/finite gain controllers mimic a H2 controller. One of our synthesis methods uses the Generalized Kalman-Yakubovich-Popov Lemma, thus realizing a convex optimization problem.

In spread spectrum systems employing parity bit selected spreading sequences, parity bits generated from a linear block encoder are used to select a spreading code from a set of mutually orthogonal spreading sequences. In this thesis, turbo receivers for SS-PB systems are proposed and investigated. In the transmitter, data bits are rst convolutionally encoded before being fed into SS-PB modulator. In fact, the parity bit spreading code selection technique acts as an inner encoder in this system without allocating any transmit energy to the additional redundancy provided by this technique. The receiver implements a turbo processing by iteratively exchanging the soft information on coded bits between a SISO detector and a SISO decoder. In this system, detection is performed by incorporating the extrinsic information provided by the decoder in the last iteration into the received signal to calculate the likelihood of each detected bit in terms of LLR which is used as the input for a SISO decoder. In addition, SISO detectors are proposed for MC-CDMA and MIMO-CDMA systems that employ parity bit selected and permutation spreading. In the case of multiuser scenario, a turbo SISO multiuser detector is introduced for SS-PB systems for both synchronous and asynchronous channels. In such systems, MAI is estimated from the extrinsic information provided by the SISO channel decoder in the previous iteration. SISO multiuser detectors are also proposed for the case of multiple users in MC-CDMA and MIMO-CDMA systems when parity bit selected and permutation spreading are used. Simulations performed for all the proposed turbo receivers show a signi cant reduction in BER in AWGN and fading channels over multiple iterations.

The objective of this thesis is to study the combination of environmental Input-Output (IO) models with Life Cycle Inventory (LCI) into a common framework which allows for regional/national environmental analyses meanwhile conserving process details. Our results show that this is possible by "adapting" the two methods: compiling LCI in matrix form and disaggregating as much as possible the IO tables. Given the poor data availability for detailed analyses at regional/national level, the results of this work suggest starting with a "traditional" IO analysis together with a Structural Path Analysis to identify the most polluting sectors and the paths through which the pollution is propagated. For the identified most polluting sectors, LCA data should be collected and fed into a tiered-hybrid IO-LCA model which gives the regional picture meanwhile conserves process details.

El sector industrial ha estat un element clau per al desenvolupament econòmic d'Espanya i de Catalunya. El que es busca en aquest treball és poder comprovar fins a quin punt aquest sector ha tingut la mateixa rellevància en el desenvolupament econòmic de Lleida. També es vol esbrinar si la industria que ha sorgit en el territori de Lleida ha estat procipiciada per les necessitats de l'entorn econòmic lleidatà o per les necessitats de descongestió de la zona industrial del Barcelonès.L'àmbit territorial de l'estudi és la província de Lleida, distingint clarament l'existència de dues zones clarament diferenciades, la Plana de Lleida (vuitena vegueria) i la zona de muntanya (novena vegueria). El període d'estudi va des de l'any 1964 fins a l'any 1989/91, podent-se distingir clarament tres etapes del cicle econòmic: desenvolupament, crisi i recuperació. Per estudiar el cicle en el sector industrial lleidatà i poder veure si ha seguit les mateixes dinàmiques que l'estatal i el català, s'utilitza el criteri que ve marcat per l'evolució de la quota d'excedent brut. Així doncs, tot procés d'acumulació passa ineludiblement per l'anàlisi de l'evolució de l'excedent econòmic. Un creixement de la quota d'excedent brut pot estar motivat per l'augment de la producció, de la productivitat i dels preus, per sobre del creixement del cost salarial. Per tant, en l'etapa de creixement de la quota d'excedent brut s'afavoreix el procés d'acumulació i en l'etapa de disminució de la quota d'excedent brut l'acumulació s'està reduint.La motivació inicial del treball ve donada perquè en principi Lleida tenia, i té encara, una sèrie de premisses importants perquè pogués desenvolupar un sector industrial: a) L'existència de matèries primeres importants, els productes agraris per poder desenvolupar tot un conjunt d'indústries conserveres i de transformació. b) El fet de trobar-se al bell mig d'una cruïlla de camins, Barcelona -Tarragona -Saragossa -Madrid- País Basc, és a dir, a prop d'altres zones industrialitzades, per poder pensar en convertir-se en una zona de descongestió. b) L'existència d'una font d'energia important: l'electricitat, dels salts hidràulics. d) L'existència d'un excedent generat en el sector agrari, a partir de finals dels anys cinquanta i principis del seixanta.Tots aquests eren elements per pensar que Lleida tenia unes potencialitats molt idònies per a la seva industrialització. Però ens trobem amb una altra realitat ben diferent: a) Que la indústria de Lleida és una indústria dependent respecte a les fluctuacions i dinamisme espanyol i català. b) L'expansió del sector industrial lleidatà s'ha basat, principalment, en el creixement de poques branques, l'alimentària, la construcció i en menor mesura els transformats metàl·lics. c) El sector industrial mostra una forta interdependència respecte al sector agrari. Així doncs, es pot establir una relació com la següent: Agricultura  Indústria  Ramaderia  Indústria. El nivell d'interdependència és molt significatiu. d) La dimensió petita del conjunt de les empreses de les branques industrials, exceptuant les branques alimentació, energia, paper i arts gràfiques i transformats metàl·lics, fa que la seva activitat productiva tingui com a destinació final, en l'àmbit territorial, el mercat lleidatà, en la seva gran majoria. L'anàlisi dels sectors econòmics i les seves interdependències, s'ha pogut realitzar a partir de la Taula Input Ouput de la ciutat de Lleida i del seu entorn més proper. A patir de la taula s'ha pogut obtenir els multiplicadors de producció, de renda i d'ocupació. També s'ha pogut obtenir la capacitat d'arrossegament dels diferents sectors econòmics, tant cap endavant com cap endarrera: indicador de Chenery-Watanabe i coeficients de Rasmussen. L'anàlisi d'interdependència de les branques es calculen a partir dels coeficients de Streit, els lligams i els multiplicadors (columna i fila). / The industrial sector has played a key role in the economic development of both Spain and Catalonia. This work seeks to examine whether this sector has been equally relevant in the economic development of Lleida. It also aims to establish whether the industry that has developed in Lleida has done so in response to the needs of the local economy or in order to help decongest the industrial zone around Barcelona.The territorial scope of the study was Lleida province, within which it is possible to distinguish two clearly differentiated zones: the Lleida Plain (8th "vegueria") and the Mountain Territory (9th "vegueria"). The period contemplated by this study was 1964 to 1989/91. This period could be divided into three clearly distinguished economic cycles, corresponding to economic development, crisis and recovery. In the study, we used the size of the gross surplus as the criterion for studying the cycle of Lleida's industrial sector, observing whether it followed the same dynamics as those of Spain and Catalonia. It is necessary to analyse all processes of accumulation in terms of the evolution of the economic surplus. An increase in the size of the gross surplus may be the result of an increase in production, productivity and/or price that exceeds increases in costs attributable to salaries. As a result, an increase in the size of the gross surplus favours the process of accumulation, while in a period in which the size of the gross surplus decreases, this accumulation diminishes.The initial reason for this work was the fact that Lleida had, and still has, a series of important reasons for wanting to develop an industrial sector: a) The existence of important supplies of raw materials, in the form of agricultural products, that could be used to develop a series of food and transforming industries. b) The fact that Lleida is located at a strategic meeting point of major route ways that connect Barcelona, Tarragona, Zaragoza, Madrid and the Basque Country. In other words, it is near other industrialised zones and could therefore become a zone of decongestion. c) The existence of an important source of energy: the electricity produced by hydroelectric power stations. d) The existence of surplus production generated by the agricultural sector since the late 1950s and early 1960s.All of these elements suggested that Lleida had an excellent potential for industrialisation. Reality, however, has proved very different: a) The industry of Lleida has proved very dependent on the fluctuations and dynamics of the Spanish and Catalan economies. b) The expansion of the industrial sector in Lleida has mainly been based on the growth of a limited number of branches of industry: the food industry, the construction industry, and - to a lesser degree - the metal working industry. c) The industrial sector has demonstrated a strong interdependence with respect to the agricultural sector. It is therefore possible to establish the following relationship: Agriculture  Industry  Livestock farming  Industry. The level of interdependence is very significant. d) The relatively small size of the group of companies constituting the industrial branches - with the exception of the food, energy, paper and graphic arts and metal working branches - has meant that their productive activity has principally focused on serving the needs of the local territory and the Lleida market. This analysis of the economic sectors and their respective interdependencies was based on the Input-Output table for the city of Lleida and its immediate hinterland. From this table, we were able to obtain the multipliers of production, income and employment. We were also able to obtain the attraction capacities of the different economic sectors, both towards and away from the area: the Chenery-Watanabe indicator and Rasmussen coefficients. The analysis of the interdependence of the different branches was calculated from the Streit coefficients, ties and multipliers (column and file).

El comercio urbano es el punto de conexión entre la producción y el consumo, el entorno a través del cual los flujos de productos transcurren desde su fabricación hasta las manos del consumidor. Y la arquitectura constituye el soporte físico de la actividad, el lugar en el cual se satisfacen los diferentes requerimientos funcionales necesarios para la comercialización de un producto. Desde los orígenes de la actividad (mediante la incorporación de sencillos elementos para la protección del producto del sol o la lluvia), hasta hoy (en los que además se recurre a la incorporación de sofisticada tecnología para persuadir al comprador a la hora de la venta), la arquitectura ha sido empleada para alojar el producto manteniéndolo en condiciones adecuadas para su venta, proporcionar condiciones de confort en el proceso del intercambio y generar un ambiente idóneo para establecer la relación entre comprador y vendedor. Debido a los diferentes cambios provocados por los avances tecnológicos, económicos, sociales y urbanísticos a lo largo de la historia, la actividad comercial cambia, evoluciona. Y la arquitectura, como escenario en el cual transcurre el comercio urbano, también se transforma, convirtiéndose en el escenario de una actividad global, en el contenedor de una actividad económica, lúdica y social. En el sistema comercial de una ciudad, es posible identificar diferentes formatos arquitectónicos, algunos con una continuada permanencia a lo largo de la historia, otros que han quedado obsoletos y han desaparecido, y otros que se generan completamente nuevos. Y si se analizara de forma comparada el comercio actual de una ciudad con el comercio de algunas décadas atrás, sería posible detectar un incremento en la cantidad de recursos arquitectónicos empleados en los diferentes formatos de venta. Dependiendo de donde se compra (tienda de barrio, supermercado, hipermercado, internet), y a pesar de que el objetivo es el mismo (vender), en la comercialización de un mismo producto son invertidas cantidades dispares de recursos arquitectónicos. Y la inversión arquitectónica de los diferentes formatos de venta hasta ahora ha sido medida únicamente por su eficacia (atracción, alcance, capacidad de venta), pero no por su eficiencia enfocada desde la sostenibilidad medioambiental. ¿Realmente existe un vínculo directo entre la cantidad de recursos empleados y la intensidad de ventas? Todos los modelos conviven y su vigencia nos confirma que generan buenos resultados. Pero, ¿cuál está mejor posicionado teniendo como referencia el impacto que generan dentro y fuera de la ciudad? Toda la infraestructura arquitectónica del comercio urbano implica una serie de inversiones (espacio, materia, energía, medios, tecnología), que constituyen una “mochila arquitectónica", visible e invisible, repercutible a cada uno de los productos que consumimos. Hoy los productos tienen muchos más kilómetros a sus espaldas, así como también tienen una carga arquitectónica mucho mayor que en décadas anteriores. Actualmente se hace una importante inversión arquitectónica para dar soporte a la actividad comercial. Y sin embargo, a diferencia de otros temas arquitectónicos como por ejemplo la vivienda, la industria o las oficinas, hay poco cuestionamiento sostenible al respecto. A la vista de todo lo anterior se hace necesario el planteamiento de diferentes preguntas, con la visión profesional del arquitecto, y dentro del marco de la sostenibilidad: ¿el comercio será siempre así? Tienen límite estas tendencias? ¿Existen vías de comercio arquitectónicamente más eficientes desde el punto de vista de la sostenibilidad medioambiental? ¿El comercio es por definición exuberante en sus medios? ¿Es necesario intervenir en la arquitectura de las formas de comercio al detalle estableciendo unas reglas para alcanzar la sostenibilidad medioambiental o bien se podría ahogar la perpetuación de la propia actividad? / Retail is the interface between production and consumption, the environment through the flux of products flows from manufacture to the consumer. The architecture constitutes the place where the different functional requeriments needed to commercialize a product are satisfied. Since the origins of the activity (through the incorporation of simple elements in order to protect the product of the sun or the rain), until today (when also sophisticated technology is incorporated to persuade the shopper during the process of purchase), architecture has been used to shelter the product keeping it in suitable conditions to be sold, to provide comfort and set up a convenient environment to establish the relation between shopper and the salesclerk. Due to the different changes derived in the city from social, economic, technological and urban advances, today retail is not only an economic activity; at the same time is a ludic and social activity. Architecture, as its scenario also changes, becoming in the scenario of a global activity, whose functional requirements go further than a simple commercial exchange. For this reason, in urban retail is possible to identify different architectonical formats, some of them with a constant permanence through history, others that have remainded obsolete and have disappeared, and others totally new. And comparing today’s retail of a city with its retail some decades before, it’s possible to detect an increase in the amount of architectural resources used in the different retail formats. According to where is bought (neighborhood’s shop, supermarket, hipermarket, internet), in spite of the purpose is the same (to sell), to commercialize the same product are invested unequal amounts of architectural resources (space, matter, energy, technology), which make up an “architectural rucksack”, visible and invisible, attributed to each one of the products that we consume. And the investment of architectural resources in the different retail formats since today has been assessed only by its effectiveness, but not for its efficiency focused from environmental sustainability. ¿Does really exist a direct link between the amount of resources used and the number of sales generated? All the commercial models coexist and their validity confirms that generate good results. But, ¿which is the best positioned according to the environmental impact generated inside and outside the city? Considerig all this, it’s necessary to raise different questions, with the profesional vision of the architect, inside the frame of sustainability: ¿Will retail be always this way? ¿Do these tendencies have any limit? ¿Do exist retail alternatives architecturally more efficient since a sustainable point of view? ¿Is retail exuberant in its resources by definition?¿Is it necessary to intercede in the architecture of retail formats establishing some rules to reach the environmental sustainability, or this could drown the continuity of the activity?

The aim of the thesis is to study some of the essential consequences of the location of Algots Ltd in three municipalities (Lycksele, Norsjö and Skellefteå) in Västerbotten County in northern Sweden. The factories were established with huge subsidies from the Swedish Government which considered the location as a major effort to stimulate regional development in Västerbotten County.The study shows that the yearly working time has increased, on average, by 80 per cent for the women who received employment in one of the factories. Both the incomemult i pi i er and the employmentmult i piier effects in Västerbotten County are rather small since the intermediate goods used by the firm are produced outside the region. The study also contain cost-benefit analysis as applied to the whole economy. Primarily due to very poor private profitability, the investment has yielded negative profitability to the whole economy except in the case of the Norsjö factory. / digitalisering@umu

Research has demonstrated a close relationship between verbal short-term (STM) and working memory (WM) and receptive language in children (Baddeley, Gathercole, & Papagno, 1998; Ellis & Sinclair, 1996). Few studies have examined the relationship between memory and language production, and these studies focus on STM only. Though correlations have been found between verbal STM and production, the nature of the correlations are unclear. The current study examined the possibility that receptive language mediates the relationship between memory and language production. Children between 3;0 and 5;11 were administered tests assessing receptive vocabulary, receptive grammar, expressive vocabulary, verbal STM, and verbal WM. Additionally, transcripts from free-play sessions were used to assess grammar production. A regression based analytic approach revealed STM and WM mediate the relationship between receptive language and productive language. The existence of these mediated relationships are discussed in relation to the role of working memory in the speech output buffer.

Purpose: To examine the dosimetric characteristics of Gafchromic EBT3 film when measuring small fields of radiation, and compare it against other common radiation detectors. Methods and Materials: EBT3 film was placed in a solid water phantom and irradiated with 6MV photons, field sizes from 10x10cm2 down to 6x6mm2. The films were scanned with a Vidar DosimetryPRO Advantage Red scanner, and analyzed with RIT113 software. The films were also scanned at different orientations and times to quantify the discrepancies associated with scanning orientation and post-exposure darkening. The same fields were measured with a PTW TN30013 farmer chamber, an Exradin T1 cylindrical ion chamber, a PTW parallel plate ion chamber, and a Sun Nuclear Edge Detector (diode). Output factors were calculated for each detector and compared for accuracy. The output factors were measured from a Varian Clinac iX, Clinac 21EX, Trilogy, and TrueBeam; as well as a Novalis Tx. The outputs from different machines at different clinics were compared. Results: The EBT3 film and Edge Detector were the only detectors that succeeded in accurately measuring the output from all field sizes; the ion chambers were too large and failed for field sizes below 4x4cm2 due to volume averaging. The dose measured with the film increased by an average of 8.8% after one week post-irradiation. The dose measured was also reduced by an average of 4.4% by scanning the film in landscape orientation, as opposed to portrait orientation. It was shown that the output factors for the smallest field of 6x6mm2--successfully measured with film and diode--varied between 0.54-0.74 for five different machines at three different clinics. Conclusions: The feasibility of using Gafchromic EBT3 film to measure very small fields of radiation is confirmed. Of the other 4 detectors used, only the diode was shown to be capable of accurately measuring small fields of radiation. The need to optimize the film dosimetry process--including the time films are scanned post-irradiation, the consistency of the scanning orientation of the calibration and subsequent films, and the measurement procedure on the computer software--is highlighted.