Academic literature on the topic 'Scalar processor'

This paper proposes a simultaneous multithreaded matrix processor (SMMP) to improve the performance of data-parallel applications by exploiting instruction-level parallelism (ILP) data-level parallelism (DLP) and thread-level parallelism (TLP). In SMMP, the well-known five-stage pipeline (baseline scalar processor) is extended to execute multi-scalar/vector/matrix instructions on unified parallel execution datapaths. SMMP can issue four scalar instructions from two threads each cycle or four vector/matrix operations from one thread, where the execution of vector/matrix instructions in threads is done in round-robin fashion. Moreover, this paper presents the implementation of our proposed SMMP using VHDL targeting FPGA Virtex-6. In addition, the performance of SMMP is evaluated on some kernels from the basic linear algebra subprograms (BLAS). Our results show that, the hardware complexity of SMMP is 5.68 times higher than the baseline scalar processor. However, speedups of 4.9, 6.09, 6.98, 8.2, 8.25, 8.72, 9.36, 11.84 and 21.57 are achieved on BLAS kernels of applying Givens rotation, scalar times vector plus another, vector addition, vector scaling, setting up Givens rotation, dot-product, matrix–vector multiplication, Euclidean length, and matrix–matrix multiplications, respectively. The average speedup over the baseline is 9.55 and the average speedup over complexity is 1.68. Comparing with Xilinx MicroBlaze, the complexity of SMMP is 6.36 times higher, however, its speedup ranges from 6.87 to 12.07 on vector/matrix kernels, which is 9.46 in average.

Technological advances in IC manufacturing provide us with the capability to integrate more and more functionality into a single chip. Today's modern processors have nearly one billion transistors on a single chip. With the increasing complexity of today's system, the designs have to be modeled at a high-level of abstraction before partitioning into hardware and software components for final implementation. This paper explains in detail the implementation and performance evaluation of a matrix processor called Mat-Core with SystemC (system level modeling language). Mat-Core is a research processor aiming at exploiting the increasingly number of transistors per IC to improve the performance of a wide range of applications. It extends a general-purpose scalar processor with a matrix unit. To hide memory latency, the extended matrix unit is decoupled into two components: address generation and data computation, which communicate through data queues. Like vector architectures, the data computation unit is organized in parallel lanes. However, on parallel lanes, Mat-Core can execute matrix-scalar, matrix-vector, and matrix-matrix instructions in addition to vector-scalar and vector-vector instructions. For controlling the execution of vector/matrix instructions on the matrix core, this paper extends the well known scoreboard technique. Furthermore, the performance of Mat-Core is evaluated on vector and matrix kernels. Our results show that the performance of four lanes Mat-Core with matrix registers of size 4 × 4 or 16 elements each, queues size of 10, start up time of 6 clock cycles, and memory latency of 10 clock cycles is about 0.94, 1.3, 2.3, 1.6, 2.3, and 5.5 FLOPs per clock cycle; achieved on scalar-vector multiplication, SAXPY, Givens, rank-1 update, vector-matrix multiplication, and matrix-matrix multiplication, respectively.

In this paper, we present a highly optimized implementation of elliptic curve cryptography (ECC) over NIST P-256 curve for an 8-bit AVR microcontroller. For improving the performance of ECC implementation, we focus on optimizing field arithmetics. In particular, we optimize the modular multiplication and squaring method exploiting the state-of-the-art optimization technique, namely range shifted representation (RSR). With optimized field arithmetics, we significantly improve the performance of scalar multiplication and set the speed record for execution time of variable base scalar multiplication over NIST P-256 curve. When compared with previous works, we achieve a performance gain of 17.3% over the best previous result on the same platform. Moreover, the execution time of our result is even faster than that over the NIST P-192 curve of the well-known TinyECC library. Our result shows that RSR can be applied to all field arithmetics and evaluate the impact of the adoption of RSR over the performance of scalar multiplication. Additionally, our implementation provides a high degree of regularity to withstand side-channel attacks.

In the ECC, scalar multiplication represents the core operation of the system. In recent years, the circuit architecture of triple processor cores or greater has been addressed in the domestic and international literature. A parallel processing concept is mainly used in this type of framework to accelerate circuit operation. In the present study, equation calculation and circuit design were employed to integrate the pipeline architecture and the parallel processing architecture and further propose an elliptic curve scalar multiplier for dual processor cores. In addition, a Xilinx XC5VLX110T FPGA was used to verify the accuracy and performance of circuit functions. The maximum frequency was 173 MHz, the number of LUTs was 14999 slices, and the time to accomplishing one scalar multiplication was only 8.8s. Compared to architectures described in recent reports, the architecture presented was faster and effectively reduced the square measure by 28%.

Different subtasks of an application usually have different computational, memory, and I/O requirements that result in different needs for computer capabilities. Thus, the more appropriate approach for both high performance and simple programming model is designing a processor having multi-level instruction set architecture (ISA). This leads to high performance and minimum executable code size. Since the fundamental data structures for a wide variety of existing applications are scalar, vector, and matrix, our research Trident processor has three-level ISA executed on zero-, one-, and two-dimensional arrays of data. These levels are used to express a great amount of fine-grain data parallelism to a processor instead of the dynamical extraction by a complicated logic or statically with compilers. This reduces the design complexity and provides high-level programming interface to hardware. In this paper, the performance of Trident processor is evaluated on BLAS, which represent the kernel operations of many data parallel applications. We show that Trident processor proportionally reduces the number of clock cycles per floating-point operation by increasing the number of execution datapaths.

The work deals with main aspects of computer efficiency increase. Object of investigation is a system consisting of processor, memory, other components and connecting links called buses. Rather different systems are used in modern world of information, so an interest arises to compare architectures of several producers. Comparison of systems is quite possible as the same architectural features bind them together: processor‘s clock speed, cache, memory, dual channel technology and others. To perform a comparative analysis, software has been used enabling to reveal increase of efficiency of separate computer components. Systems chosen for study are rather new from the point of view of technology: Intel Pentium 4, AMD Athlon XP and AMD Sempron. Experiments having been fulfilled, it came out that efficiency of a system for the most part depends on processor capacity: increase of its clock speed results in 9 – 13%, L1 cache has an effect even up to 1350% (theoretically), L2 cache – 30 – 38%. HyperThreading has been observed to mostly result in operations with floating point numbers (even up to 68%), and branch prediction would have theoretically to increase efficiency up to 47%. Estimating indicator of efficiency of the whole system, the results show that the main role belongs to processor. Influence of other components of the system is less noticeable. Working peculiarities of memory type determine rate of data selection and transmission from memory. The study has shown that... [to full text]

The goal of this project was to study pipelined processor architectures along with instruction and data cache. Chosen pipelined architecture should be designed and implemented using VHDL language. Firstly, I decided to implement the subscalar architecture first, secondly, three versions of scalar architecture. For these architectures synthesis into FPGA was done and performance of these architectures was compared on chosen algorithm. In the next part of this thesis I designed and implemented instruction and data cache logic for both architectures. However I was not able to synthetise these caches. Last chapter of this thesis deals with the superscalar architecture, which is the architecture of nowadays.

Cette thèse se consacre à une analyse théorique puis numérique d'une certaine classe d'équations aux dérivées partielles stochastiques (EDPS) : les lois de conservation scalaires avec viscosité et avec un forçage aléatoire de type additif et bruit blanc en temps. Un exemple typique est l'équation de Burgers stochastique, motivée par la théorie de la turbulence. On s'intéresse particulièrement au comportement en temps long des solutions de ces équations à travers une étude des mesures invariantes. La partie théorique de la thèse constitue le chapitre 2. Dans ce chapitre, on prouve l'existence et l'unicité d'une solution au sens fort. Pour cela, des estimations sur les normes de Sobolev jusqu'à l'ordre 2 sont établies. Dans la seconde partie du chapitre 2, on montre que la solution de l'EDPS admet une unique mesure invariante. On se propose dans le chapitre 3 d'approcher numériquement cette mesure invariante. À cette fin, on introduit un schéma numérique dont la discrétisation spatiale est de type Volumes Finis et dont la discrétisation temporelle est une méthode d'Euler semi-implicite. Il est montré que ce type de schéma respecte certaines propriétés fondamentales de l'EDPS telles que la dissipation d'énergie et la contraction L1. Ces propriétés assurent l'existence et l'unicité d'une mesure invariante pour le schéma. À l'aide d'un certain nombre d'estimations de régularité, on montre ensuite que cette mesure invariante discrète converge, lorsque le pas de temps et le pas d'espace tendent vers zéro, vers l'unique mesure invariante pour l'EDPS au sens de la distance de Wasserstein d'ordre 2. Enfin, des expériences numériques sont effectuées sur l'équation de Burgers pour illustrer cette convergence ainsi que des propriétés à petites échelles spatiale relatives à la turbulence
This devoted to the theoretical and numerical analysis of a certain class of stochastic partial differential equations (SPDEs), namely scalar conservation laws with viscosity and with a stochastic forcing which is an additive white noise in time. A particular case of interest is the stochastic Burgers equation, which is motivated by turbulence theory. We focus on the long time behaviour of the solutions of these equations through a study of the invariant measures. The theoretical part of the thesis constitutes the second chapter. In this chapter, we prove the existence and uniqueness of a solution in a strong sense. To this end, estimates on Sobolev norms up to the second order are established. In the second part of Chapter~2, we show that the solution of the SPDE admits a unique invariant measure. In the third chapter, we aim to approximate numerically this invariant measure. For this purpose, we introduce a numerical scheme whose spatial discretisation is of the finite volume type and whose temporal discretisation is a split-step backward Euler method. It is shown that this kind of scheme preserves some fundamental properties of the SPDE such as energy dissipation and L^1-contraction. Those properties ensure the existence and uniqueness of an invariant measure for the numerical scheme. Thanks to a few regularity estimates, we show that this discrete invariant measure converges, as the space and time steps tend to zero, towards the unique invariant measure for the SPDE in the sense of the second order Wasserstein distance. Finally, numerical experiments are performed on the Burgers equation in order to illustrate this convergence as well as some small-scale properties related to turbulence

Aquesta tesis es centra en l’estudi de la transferència d’aigua i sediments des de les àrees font de sediments fins les zones de sedimentació a múltiples escales temporals (des de dades amb una freqüència de cinc minuts fins informació de tot un segle) i espacials (des de vessants fins a conques), i les seves implicacions en la morfologia de la llera de la conca de l’Alt Cinca, una conca de muntanya localitzada al vessant sud dels Pirineus. A escala de micro-conca, les dades d’alta resolució obtingudes durant 5 anys en dos badlands contrastats (0.3 ha cadascun) revelen com la pluja controla els processos erosius associats a l’escolament superficial, m’entre que les baixes temperatures tenen una relació significativa amb els processos de moviments en massa. La morfometria d’aquestes superfícies, conjuntament amb la cobertura vegetal són factors clau que determinen els principals processos geomorfològics i els associats canvis topogràfics. Els principals processos observats han estat seqüències d’Erosió i Sedimentació (Cutting and Filling) i Moviments Gravitacionals (Mass Wasting). Tot i que els badlands tenen un paper important en la producció de sediments, el balanç de sediments de la conca del riu Soto (10 km2) indica que aquestes superfícies no sempre controlen l’exportació de sediments a la sortida de petites conques de muntanya amb caràcter intermitent. Aquest fet és degut a la fluctuació de la connectivitat funcional de la xarxa de drenatge causada per la freqüència i magnitud dels polsos d’aigua i sediments durant crescudes sobtades o flashy. La xarxa de drenatge actua com a font i zona d’emmagatzematge de sediments i es clau per entendre les marcades diferències que hi ha en la proporció del sediment que s’exporta en relació a la producció o també anomenat Sediment Delivery Ratio. Els canvis en els usos de sòl en moltes conques de muntanya constatats des de els anys 50 del segle XX tenen un efecte directe en la generació d’escolament (quantitat i magnitud) i en la producció de sediments. La majoria de la superfície de la conca de l’Alt Cinca (1565 km2) ha sofert aforestació, que ha resultat en una reducció de la connectivitat sedimentaria estructural. La construcció de terrasses afecta la connectivitat molt més que els canvis en la coberta del sòl. Les terrasses generalment redueixen la connectivitat degut a l’establiment de zones planes entre mig de zones en pendent. Contràriament, a una escala més local, les terrasses poden incrementar la connectivitat degut a la convergència de flux produïda per les pròpies estructures, o per la caiguda d’aquestes degut a l’abandonament. La construcció de carreteres modifica el pendent i la xarxa de drenatge, fet que comportarà canvis en la connectivitat estructural, que a la vegada poden afectar els processos erosius en les zones veïnes. Així, els fluxos d’aigua i sediments a la conca de l’Alt Cinca han estat àmpliament modificats durant l’últim segle, amb implicacions directes en la forma de la llera. A més a més, impactes locals derivats de les extraccions d’àrids, construcció d’esculleres i embasaments també han condicionat la dinàmica sedimentaria d’aquest riu, amb un impacte directe sobre la morfologia. Aquesta situació ha generat una metamorfosis de la morfologia del riu en la part baixa de l’Alt Cinca (12 km), canviant d’un patró trenat, molt dinàmic, a un patró més estable amb una tendència cap a canal únic. Els resultats obtinguts indiquen que el tram d’estudi està assolint un nou equilibri morfo-sedimentari imposat pels canvis en els fluxos d’aigua i sediments ocorreguts en el darrer segle, incloent les pertorbacions antròpiques que han modificat la geometria del canal i les característiques morfològiques de la llera. S’han observat un total de tres fases en la seva evolució: abans de l’any 1927, el tram d’estudi es trobava en una situació de quasi-equilibri majoritàriament condicionada per les riuades. Entre l’any 1927 i 2012 el riu s’ha ajustat a les diferents pertorbacions que ha tingut a múltiples escales temporals i espacials. Aquest ajust s’ha portat a terme mitjançant dos canvis contrastats en les característiques morfològiques. Finalment, després de l’any 2012, els resultats indiquen que el riu pot haver assolit de nou un nou equilibri, ajustant-se als fluxos d’aigua i sediment imposats i a la nova configuració del canal. Aquesta tesis presenta innovadors mètodes quantitatius per a l’estudi de la producció de sediments i la transferència entre els diferents compartiments de les conques fluvials. La principal novetat en la majoria dels capítols de la tesis recau en l’elevada resolució, de les dades obtingudes, tant temporal com espacial. Els resultats obtinguts en aquesta tesi permeten entendre millor el funcionament dels sistemes fluvials i la seva evolució, aspectes claus per donar suport en la millora i gestió de conques hidrogràfiques de muntanya.
Esta tesis se centra en el estudio de la transferencia de agua y sedimentos desde las áreas fuente de sedimentos hasta las áreas de sedimentación a múltiples escales temporales (desde datos con una frecuencia de cinco minutos hasta información de un siglo) y espaciales (desde laderas hasta cuencas), y sus implicaciones en la morfología del cauce en la Cuenca del Alto Cinca (vertiente sur de los Pirineos). A escala de micro-cuenca, los datos de alta resolución obtenidos durante 5 años en dos badlands contrastados (0.3 ha cada uno) revelan como la lluvia controla los procesos erosivos asociados a la escorrentía superficial, mientras que las bajas temperaturas tienen una relación significativa con los procesos de movimientos en masa. La morfometría de estas superficies, conjuntamente con la cobertura vegetal, son factores clave que determinan los principales procesos geomorfológicos y los cambios topográficos asociados. Los principales procesos observados han sido secuencias de Erosión y Sedimentación (Cutting and Filling) y Movimientos Gravitacionales (Mass Wasting). Pese a que los badlands tienen un papel importante en la producción de sedimentos, el balance de sedimentos de la cuenca del rio Soto (10 km2) indica que estas superficies no siempre controlan la exportación de sedimentos a la salida de pequeñas cuencas de montaña con carácter intermitente. Esto principalmente se debe a la fluctuación de la conectividad funcional de la red de drenaje causada por la frecuencia y magnitud de los pulsos de agua y sedimentos durante las crecidas súbitas o flashy. La red de drenaje actúa como fuente y zona de almacenamiento de sedimentos, y es clave para entender las marcadas diferencias que hay en la proporción de sedimento que se exporta en relación a la producción o Sediment Delivery Ratio. Los cambios en los usos del suelo en muchas cuencas de montaña constatados desde los años 50 del siglo XX tienen un efecto directo en la generación de escorrentía (cantidad y magnitud) y en la producción de sedimentos. La mayoría de la superficie de la cuenca del Alto Cinca (1565 km2) ha sufrido forestación, que ha resultado en una reducción de la conectividad sedimentaria estructural. La construcción de terrazas afecta la conectividad mucho más que los cambios en la cobertura del suelo. A una escala más local, las terrazas pueden incrementar la conectividad debido a la convergencia de flujo producida por las propias estructuras, o por la caída de estas debido a su abandono. La construcción de carreteras modifica la pendiente y la red de drenaje, hecho que comporta cambios en la conectividad estructural, que a su vez pueden afectar a los procesos erosivos en las zonas vecinas. Así, los flujos de agua y sedimento en la cuenca del Alto Cinca han estado ampliamente modificados durante el último siglo, con implicaciones directas en la morfología del canal. Además, impactos locales derivados de las extracciones de áridos, construcción de escolleras y embalses también han condicionado la dinámica sedimentaria de este río, con un impacto directo sobre la morfología. Esta situación ha generado una metamorfosis de la morfología del río en la parte baja del Alto Cinca (12 km), cambiando de un patrón trenzado, muy dinámico, a un patrón más estable con una tendencia hacia el canal único. Los resultados obtenidos indican que el tramo de estudio está alcanzando un nuevo equilibrio morfo-sedimentario impuesto por los cambios en los flujos de agua y sedimentos ocurridos durante el último siglo, incluyendo las perturbaciones antrópicas que han modificado la geometría del canal y las características morfológicas del cauce. Se han observado un total de tres fases en su evolución: antes de 1927, el tramo de estudio se encontraba en una situación de casi-equilibrio, mayoritariamente controlada por las crecidas. Entre el año 1927 y 2012 el río se ha ajustado a las diferentes perturbaciones que ha tenido a múltiples escalas temporales y espaciales. Este ajuste se ha llevado a cabo mediante dos cambios contrastados en las características morfológicas. Finalmente, después del año 2012, los resultados indican que el río puede haber alcanzado un nuevo equilibrio, ajustándose a los flujos de agua y sedimento impuestos y la nueva configuración del canal. Esta tesis presenta innovadores métodos cuantitativos para el estudio de la producción de sedimentos y la transferencia entre los diferentes compartimentos de las cuencas fluviales. La principal novedad en la mayoría de los capítulos de la tesis recae en la elevada resolución de los datos obtenidos, tanto temporal como espacial. Los resultados obtenidos en esta tesis permiten entender mejor el funcionamiento de los sistemas fluviales y su evolución, aspectos clave para dar soporte y apoyo en la mejoría y gestión de cuencas hidrográficas de montaña.
This thesis focusses on the study of water and sediment transfer from sources to sinks at multiple temporal (from 5-min data to a century data sets) and spatial (from slope to catchment scales) scales and their implications for channel morphology in the Upper Cinca catchment, a mountain catchment located in the Southern Pyrenees. At the micro-catchment scale, our 5-year High Resolution Data Set of two contrasted badlands (around 0.3 ha each) reveal as rainfall control overland-surface flow processes while low temperatures have a significant relation with mass movement-based processes. Morphometry together with vegetation cover are key factors determining main geomorphic processes and associated topographic changes. Main observed geomorphic processes were Cutting and Filling and Mass Wasting. Although badlands may have an important role on sediment production, the 2-year sediment budget of the Soto catchment (10 km2) indicates that badlands do not always control the export of sediments at the outlet of small intermittent mountain catchments. This is mainly due to the fluctuation of the functional connectivity of the channel network caused by the frequency and magnitude of water and sediment pulses during flashy floods. The channel drainage network acts as sediment source and sink and it is key to understand marked differences in the Sediment Delivery Ration. Land use and cover in many mountain catchments have been modified since the fifties of the 20th century, having a direct effect on runoff and sediment production. Most of the area of the Upper Cinca catchment (1565 km2) has undergone afforestation, which resulted in a decrease of structural sediment connectivity. Terracing affects connectivity much more than changes in land cover. Terraces generally reduce connectivity due to the establishment of flat areas between slopes and, contrarily, locally, may increase connectivity due the convergence produced by the structures or the collapse of terraces due to abandonment. Road construction, however, modify slope and the drainage network, which leads to changes in connectivity that could affect erosional processes in the neighbouring areas. Thus, water and sediment fluxes through the Upper Cinca are spatially and temporal dynamic and have been dramatically modified in the last century, with direct implications on channel morphology. Additionally, localised disturbances such as gravel mining, channel embankments and dams have also impacted on sedimentary dynamics, thus channel morphology. This situation led to a river metamorphosis, changing from a braided pattern to a more static channel towards a wandering pattern. We hypothesise that the lowermost 12-km reach of the Upper Cinca has reaching a new equilibrium imposed by catchment-scale changes of water and sediment fluxes caused by global changes, but also influenced by localised human-disturbances that modify channel geometry and morpho-sedimentary characteristics. Three phases were identified: before 1927, the reach remained in a quasi-equilibrium state imposed, mainly, by water and sediment supply during flood events. During the period 1927-2012 the river adjusted to the disequilibrium imposed by disturbances acting at different temporal and spatial scales, yielding two contrasted channel states. Finally, after 2012, we hypothesise that the river may be reaching again a new equilibrium, adjusting to the imposed water and sediment fluxes and the new channel configuration. This thesis presents some novel quantitative methods for the study of sediment production and transfer between the different compartments of fluvial catchments. The main transversal novelty in all the methods used in each chapter lies in the high resolution of the data obtained. This comprehensive analysis aids at understanding the functioning of the river system and their evolution based on multiple-scale disturbances, which can help to support integrated watershed management practices or plans.

A existência de um méson escalar-isoescalar leve, conhecido como ?, foi proposta pela primeira vez na década de 60. A partícula tinha então um papel importante na construção teórica das interações ?? mas, apesar dos esforços experimentais, ela não foi detectada nos anos que se seguiram. Essa situação foi radicalmente alterada em 2001, quando uma ressonância escalar foi descoberta nos canais ?+?- do decaimento D+ -> ?+?-?+ e recebeu o rótulo ?(500). Sua existência é bem estabelecida hoje em dia. Contudo, no tratamento dos dados dos vários grupos experimentais são empregadas expressões com pouca base teórica e, por isso, os valores de sua massa e largura ainda são mal conhecidos. Neste tipo de decaimento, a formação da ressonância pode se dar no vértice fraco. Em sua subseqüente propagação, ocorrem as chamadas interações de estado final, cuja descrição não é trivial. Normalmente, essas interações não são levadas em conta de maneira criteriosa na análise de dados experimentais. Neste trabalho introduzimos uma função _(s) que descreve a propagação e decaimento da ressonância em presença das interações de estado final. No regime elástico, a fase de _(s) é determinada pelo chamado teorema de Watson, segundo o qual ela deve ser a mesma do espalhamento. Conseguimos estabelecer, sem ambigüidades, como a informação do espalhamento deve ser usada de forma a determinar não somente a fase de _(s), mas também seu módulo. Nosso principal resultado é uma expressão para _(s) em termos da fase elástica e de uma outra fase relacionada a uma integral de loop bem controlada. Três casos particulares foram explorados numericamente: os modelos sigma linear e não linear e ainda um modelo fenomenológico que leva em conta o acoplamento de canais p´?on-p´?on e k´aon-k´aon. Em consonância com a teoria quântica de campos, nosso resultado incorpora a unitariedade, considera a ressonância como grau de liberdade explícito e representa, ainda, uma generalização do procedimento usual de unitarizacao pela matriz K. Por permitir uma ligação clara entre espalhamento e produção, a função _(s) pode ser útil na análise de dados experimentais e ajudar na determinação da posição do pólo do ? e de outras ressonâncias escalares.
The existence of a light scalar-isoscalar meson, known as ?, was suggested in the 60\'s. This particle played an important role in the theoretical construction of ?? interactions but, in spite of all experimental effort, it failed to be detected. This scenario changed radically in 2001, when a scalar-isoscalar resonance was discovered in the ?+?- channel of the D+ -> ?+?-?+ decay and was called ?(500). Nowadays, its existence is rather well established. However, in the analysis of experimental data, expressions loosely based on theory are employed and therefore its mass and width are still not well known. In this kind of decay, the production of the resonance may occur at the weak vertex. When it propagates, final state interactions take place. Usually these interactions are not properly taken into account in data analysis. In this work, we introduce a function _(s), which describes the propagation and decay of the resonance in the presence of the final state interactions. In the elastic regime, the phase of _(s) is determined by the Watson\'s theorem, which states that it must be the same as the scattering phase. We were able to establish, unambiguously, how the information from scattering should be used to determine not only the phase of _(s) but also its modulus. Our main result is an expression for _(s) in terms of the elastic phase and another one related to a well controlled loop integral. Three special cases are explored numerically, namely: the linear and non linear sigma models and a phenomenological model that takes into account the coupling between pion-pion and kaon-kaon channels. In agreement with quantum field theory, our result encompasses unitarity, treats the resonance as an explicit degree of freedom and, moreover, corresponds to a generalisation of the usual K-matrix unitarization procedure. Since it represents a clear way to relate scattering and production, our function _(s) can be useful in data analysis and may be instrumental in the determination of the pole position of the ? as well as other scalar resonances.

Seismic, deformation, and gas activity (unrest) typically precedes volcanic eruptions. Successful volcanic event forecasting depends on the quality of the surveillance network for detecting any changes in volcano behaviour. To interpret the geochemical and geophysical precursors correctly it is important to understand the volcanic processes that occur prior and during volcanic eruptions. Detailed knowledge of the volcano internal structure, the rheology of the magmas, the time scales of the processes occurring at depth and the characteristics of past unrest episodes, must be combined with an adequate monitoring network to improve the volcanic hazard forecast. However, these aspects have received little attention in monogenetic volcanoes. The aim of my PhD Thesis is to improve our understanding on monogenetic volcanism, its causes and dynamics, and to help anticipating the volcanic activity. I have focused on three main aspects of this problem. The first one is the calculation of the rheological properties of magmas during mixing. The second aspect I have addressed are the processes and time scales that lead to monogenetic eruptions with the aim to better interpret volcanic unrest and improve eruption forecasts. Finally, I have investigated the seismic unrest periods of historical monogenetic eruptions from a compilation of historical accounts worldwide. The results provide a conceptual framework for better anticipating monogenetic eruptions and should lead to improved strategies for mitigation of their associated hazards and risks.
Las erupciones volcánicas están generalmente precedidas por la actividad sísmica, la deformación y la desgasificación (unrest). El éxito en la predicción del evento volcánico depende de la calidad de la red de vigilancia para detectar cualquier cambio en el comportamiento del volcán. Para interpretar los precursores geoquímicos y geofísicos correctamente es importante entender los procesos volcánicos que ocurren antes y durante las erupciones volcánicas. El conocimiento en detalle de la estructura interna del volcán, la reología de los magmas, las escalas de tiempo de los procesos que ocurren en profundidad y las características de los episodios pasados de unrest, debe combinarse con una red de vigilancia adecuada para mejorar el pronóstico de los eventos volcánicos. Sin embargo, estos aspectos han recibido poca atención en los volcanes monogenéticos. El objetivo de mi tesis doctoral es mejorar nuestra comprensión sobre el vulcanismo monogenético, sus causas y su dinámica, con el objetivo de mejorar la posibilidad de anticiparse a la actividad volcánica. Me he centrado en tres aspectos principales de este problema. El primero es el cálculo de las propiedades reológicas de los magmas durante los eventos de mezcla. El segundo aspecto es el estudio de los procesos, junto con sus escalas temporales, que llevan a erupciones monogenéticas con el fin de interpretar mejor la actividad volcánica y mejorar los pronósticos de una erupción. Por último, he investigado los períodos de unrest sísmico de erupciones monogenéticas históricas en todo el mundo mediante una compilación de documentos históricos. Los resultados proporcionan un marco conceptual que permite mejorar la predicción de erupciones monogenéticas y deberían conducir a mejores estrategias para mitigar sus peligros y riesgos asociados.

Thesis (Ph. D.) -- University of Maryland, College Park, 2008.
Thesis research directed by: Applied Mathematics and Scientific Computation Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

AbstractNature-based solutions (NBS) implementation in urban contexts has proven outcoming multiple benefits to reverse the current trend of natural resources’ degradation adversely affecting biodiversity, human health, and wellbeing. Yet, the current urban-planning policy frameworks present a rigid structure to integrate NBS definitions, and their co-benefits to get mainstreamed and up scaled on a wider urban spatial dimension. In this research, we test a complete co-creation pathway that encourages decision-makers to embed citizen engagement methodologies as an approach to co-design and co-implement NBS in shared-governance processes aiming to increment the greening of urban spaces, towards more inclusive and climate resilient cities. On one hand, we assess a tendency to involve a multiplicity of stakeholders that collaborate to the establishment of an Urban Innovation Partnership (UIP) aiming at increasing the social awareness around NBS themes, and at the same time tackling both financial and governance aspects. On the other hand, the innovation embedded in NBS paves the way to combine a multi-scalar flexibility in implementation tools and place-based urban actions, hence resulting in widespread economic, environmental, and social impacts in place. The novelty in embedding the co-creation process in urban-planning practice lies in catalyzing resources towards the transposition of research into practice through policy and planning tools for local authorities and decision-makers. Three front-runner cities (Hamburg, London, and Milan) are under investigation as part of Clever Cities—a Horizon 2020 project—aiming at implementing NBS in diverse urban-regeneration processes, through nine up-running Urban Living Labs (ULLs). Grounded on a comparative analysis of these three cities, key characterization for NBS implementation framework could be categorized into: (1) current urban-planning greening strategies in each context, (2) specific environmental and societal challenges addressed, (3) different typologies and scales of NBS integration within urban morphologies, (4) specific governance process as response to co-design and co-implementation processes, and (5) availability of financial investment and main stakeholders. As research results, we emphasize using co-creation approach in urban planning to embed and upscale NBS in an inclusive shared-governance process, hence contributing to social awareness and acceptance. Meanwhile, spatial, and financial challenges could be majorly resolved using a multi-scalar approach to manage newly embedded urban-greening policies at the urban level. Lastly, the implementation scale of NBS with local communities requires a radical paradigmatic shift in societal, individual and administrative urban-planning practices.

In our world, where most systems become embedded systems, the approach of designing embedded systems is still frequently similar to the approach of designing organic systems (or not embedded systems). An organic system, like a personal computer or a work station, must be able to run any task submitted to it at any time (with certain constrains depending on the machine). Consequently, it must have a sophisticated general purpose Operating System (OS) to schedule, dispatch, maintain and monitor the tasks and assist them in special cases (particularly communication and synchronization between them and with external devices). These OSs require an overhead on the memory, on the cache and on the run time. Moreover, generally they are task oriented rather than machine oriented; therefore the processor's throughput is penalized. On the other hand, an embedded system, like an Anti-lock Braking System (ABS), executes always the same software application. Frequently it is a small or medium size system, or made up of several such systems. Many small or medium size embedded systems, with limited number of tasks, can be scheduled by our proposed hardware architecture, based on the Motorola 500MHz MPC7410 processor, enhancing its throughput and avoiding the software OS overhead, complexity, maintenance and price. Encouraged by our experimental results, we shall develop a compiler to assist our method. In the meantime we will present here our proposal and the experimental results.