Dissertationen zum Thema „Multiple scale process“

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.
Includes bibliographical references (p. 247-255).
This research developed a methodology to assess the design of complex large-scale products with respect to the performance of their production processes. In complex large-scale projects, physical and functional relationships among the product systems and components, along with concurrency and co-location of their production processes, generate inter-system process dependencies that drive the relative production rates among the systems. The methodology links the complexity of the product to the complexity of the production process at the level of detail of the single component and task to model the impacts of inter-system process dependencies on production performance. This detailed focus makes the methodology highly responsive to changes in design and technology and able to capture primary, secondary and tertiary impacts of change on production performance. Based on the methodology, a dynamic process simulation model has been developed to systematically assess different combinations of design and technology alternatives across multiple dimensions of production performance. Performance measures include project duration, costs, resource utilization and index of workers' exposure to dangerous conditions. Simulated scenario testing based on actual data from a construction project, the renovation of Baker House (MIT building W7), demonstrates that 1) inter-system process dependencies strongly influence production performance, 2) these links build their dynamic effects on production performance at the detailed task and component level, and 3) the nature of the links and their spatial and temporal location vary as changes are introduced in the design and in the production specifications. One important consequence is that the specification and optimization of the production processes for product systems and components as separate from one another leads to solutions that may be sub-optimal for the performance of the whole project. In addition, the specification and the representation of complex production processes at the aggregate level fails to capture important impacts of design and technology changes and, thus, leads to inconsistent duration and cost estimates.
by Alessandra Orsoni.
Sc.D.

The industry is facing major challenges today. The challenges are tougher global competition, customers who require individualized products and shorter product lifecycles. The predicted industrial revolution is a way to deal with these challenges. Industry 4.0 includes strategies linked to several technologies that will meet the new needs. Smart factory is a central concept in industry 4.0, which involves connected technologies of various kinds. Such as digital manufacturing technology, network communication technology, computer technology, automation technology and several other areas. In this work, these were defined as smart factory technologies. Implementing such technologies will result in improved flexibility, resource productivity and efficiency, quality, etc. But, implementing smart factory technologies poses major challenges for the companies. Laboratory environments can be utilized to address the challenges. This results in a new problem, how to transfer a smart factory technology developed in a laboratory environment to a full-scale production system. In the literature study no, structured approach was identified to handle this challenge. Therefore, the purpose of this work was to: create a work process that supports the technology transfer from a smart factory compliant laboratory environment to a full-scale production system. To justify the purpose, the following research questions were answered: RQ1: What are the differences in the operating environment between the laboratory and the full-scale production system? RQ2: How is a smart factory technology determined ready to be implemented into a full-scale production system? RQ3: What critical factors should a work process for the implementation of smart factory technologies include? The research questions were answered by conducting a multiple-case study in collaboration with Scania CV AB. During the case studies, interviews, observations and other relevant types of data collection were conducted. The results were as follows: RQ1: How difficult it is to transfer a technology from a laboratory environment to a full-scale production system depends on how large the differences between these are. The general difference is that laboratory environments are used to experiment and develop technologies and a full-scale production system is used to produce products. Some want the laboratory environment to be an exact copy of a full-scale production system, but this is not appropriate because it means you lose the freedom of experimentation and it would be much more expensive. RQ2: Determining whether a smart factory technology is ready consists of two parts, laboratory activities and pilot testing. A structured assessment method has been developed. The laboratory operations reduce the risks and contribute to raising the degree of maturity of the technology. In pilot testing, it is important not to interfere with the full-scale production system stability. This is the reason for doing pilot testing in a delimited area first and checking that the technology works as desired. RQ3: The critical factors identified were: competence and knowledge, technology contributing to improvements, considering risks with implementation, cost versus potential improvement, clear goals and reason for implementation and communication.

Le développement de produits ayant un taux de matière grasse réduit est, tant d’un point de vue économique que nutritionnel, un enjeu majeur. La réduction de ce taux peut être réalisée à travers la dispersion d’une phase aqueuse dans la matière grasse initiale. Cette dispersion est couramment réalisée industriellement par mélange en voie liquide, mais le recours à des tensioactifs est nécessaire au maintien d’une émulsion stable. Une autre alternative peut être trouvée dans l’incorporation d’eau à l’intérieur de la matière grasse dans son état partiellement cristallisé. Cette méthode tire avantage de l’extrême viscosité de la matrice grasse lorsqu’une partie de celle-ci est à l’état solide, permettant une émulsion homogène, finement dispersée et stable aux temps longs sans ajout de tensioactifs. Le mélange de l’eau dans cette matrice grasse ouvre des questions sur la dispersion et la fragmentation d’un fluide faiblement visqueux dans un fluide extrêmement visqueux. Il représente également un défi technologique.Les travaux de cette thèse ont porté sur l'incorporation d'eau par fragmentation dans une matière grasse partiellement cristallisée, en considérant le beurre comme système modèle. Cette étude a nécessité le développement puis l’utilisation d’un dispositif de mélange à l’échelle laboratoire, conjointement à des mélangeurs à l’échelle pilote. La mésostructure résultante a pu être étudiée grâce à l’utilisation de la µ-tomographie aux rayons X, permettant une mesure en trois dimensions des caractéristiques de la dispersion. L'étude des mécanismes d’incorporation et de fragmentation des gouttes d'eau dans la matière grasse a permis de guider le dimensionnement d'un procédé continu à l’échelle industrielle. Enfin, les propriétés d’usage (exsudation, texture …) ont été étudiées sur des beurres préparés aux deux échelles, ce qui a permis de mieux comprendre leur dépendance aux conditions de mélange et de stockage
From both an economic and nutritional point of view, the development of products with a reduced fat content is a major challenge. This can be achieved by dispersing an aqueous phase in the initial fat. This dispersion is usually achieved industrially by liquid mixing, but surfactants are needed to maintain a stable emulsion.Another alternative is to incorporate water into the fat in its partially crystallized state. This method takes advantage of the extreme viscosity of the fat matrix when part of it is in a solid state, enabling a homogeneous, finely dispersed emulsion that is stable over long timescales without the addition of surfactants.The mixing of water in this fatty matrix raises questions about the dispersion and fragmentation of a low-viscosity fluid in an extremely viscous one. It also represents a technological challenge.This thesis focused on the incorporation of water by fragmentation into a partially crystallized fat, using butter as a model system. This study involved the development and use of a laboratory-scale mixing device, in conjunction with pilot-scale mixers. The resulting mesostructure was studied using X-ray µ-tomography, enabling three-dimensional measurement of dispersion characteristics. The study of the mechanisms of incorporation and fragmentation of water droplets in the fat was used to guide the dimensioning of a continuous process on an industrial scale. Finally, usage properties (exudation, texture, etc.) were studied on butters prepared on both scales, providing a better understanding of their dependence on mixing and storage conditions

Distributed hydrologic modeling under the changing climate and environment is hampered by the difficulties in the representation of small scale variability. Identifying and understanding the links between spatial patterns of hydrologic processes at various scales may shed light on the search for simpler and yet effective representations of variability. The main objective of this thesis is to gain useful insight for the spatial aggregation of hydrologic processes by analyzing hydrologic systems at multiple spatial scales and conducting diagnostic simulations across scales. We first identified patterns of hydrologic processes by 1) comparing the surface runoff hydrographs (area-averaged discharges) from 12 hillslopes (0.5˜3 ha) with spatial proximity in agricultural land in Iowa over 72 runoff events; and 2) analyzing˜1000 recession curves observed in the nested Iowa and Cedar River basins (7~17000km2) over the period of 1988-2012 using consistent methods. We then used recession as an example to run diagnostic simulations in the Cedar River basins to reproduce the observed spatial patterns of hydrologic responses. The success allows us to decipher the link between the spatial pattern of processes at the small scale and that at larger scales. Results from this thesis demonstrate the usefulness of the "multiscale-analysis" approach and show that accounting for both the organization and randomness of the processes variability at the small scale can shape the hydrologic response at larger scales.

Have you thought of why you get tired or why you get hungry? Something in your body keeps track of time. It is almost like you have a clock that tells you all those things.

And indeed, in the suparachiasmatic region of our hypothalamus reside cells which each act like an oscillator, and together form a coherent circadian rhythm to help our body keep track of time. In fact, such circadian clocks are not limited to mammals but can be found in many organisms including single-cell, reptiles and birds. The study of such rhythms constitutes a field of biology, chronobiology, and forms the background for my research and this thesis.

Pioneers of chronobiology, Pittendrigh and Aschoff, studied biological clocks from an input-output view, across a range of organisms by observing and analyzing their overt activity in response to stimulus such as light. Their study was made without recourse to knowledge of the biological underpinnings of the circadian pacemaker. The advent of the new biology has now made it possible to "break open the box" and identify biological feedback systems comprised of gene transcription and protein translation as the core mechanism of a biological clock.

My research has focused on a simple transcription-translation clock model which nevertheless possesses many of the features of a circadian pacemaker including its entrainability by light. This model consists of two nonlinear coupled and delayed differential equations. Light pulses can reset the phase of this clock, whereas constant light of different intensity can speed it up or slow it down. This latter property is a signature property of circadian clocks and is referred to in chronobiology as "Aschoff's rule". The discussion in this thesis focus on develop a connection and also a understanding of how constant light effect this clock model.

Includes bibliographical references.
Biological invasions are a significant ecological and economic global crisis. Protected areas also suffer from the increased burden that invasions place on their resources and the impacts placed on the ecosystem. However, management requires an ecological foundation which can inform best practice and optimize its responses. l explored the patterns and processes of invasion in Kruger National Park (KNP), South Africa; a large national park situated in the Lowveld savanna ecosystem. l used spatially-explicit alien plant data at various scales from a national database, the whole of KNP, a specific region, river system, and small scale plots in one invaded area of KNP. Using various statistical techniques, primarily classification and regression tree analysis, logistic regression, ANOVA, Nestedness and spatial pattern analysis, I assessed the relationship between the patterns observed at a specific spatial grain and extent, discussing the implications for invasion ecology and management. Using this knowledge and conceptual tools, I developed a new framework and model which contributes to invasion theory. Scale is a critical component in evaluating alien plant invasions. Without careful consideration of scale, studies from different scenarios cannot be compared and the science of invasion ecology will not advance. I provide a framework for assessing the risks of plant invasions in a watershed, using both an area- and species-approach, highlighting areas of current and future potential concern. I also explore the role of intentional introduction of ornamental plants and discuss management approaches for dealing with this. Evaluating a riparian system provides insights into how different patches in a landscape are differentially invaded, and how patch type characteristics need to be considered carefully for management and monitoring. I also describe how reconstructing the invasion history of a species, complemented by fine scale assessment, provides insights into species-specific spread models, and also how these types of studies can input into general theories, such as the role of propagule pressure. These components together provide insight into the dynamics of alien plant invasions in an African savanna and protected area system.

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.

Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.
Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.

碩士
國立中央大學
機械工程學系
104
With the continuous progress of digital communication technology, making object digitized and use three dimensional printers to reproduce could be achieved by reverse engineering technology. These process utilize digital three dimension model to achieve. However, whether using the Shape-From-Silhouettes (SFS) method with single 2D calibration pattern or Stereoscopic to reconstruct a three-dimension model, there are size limits and difficulty for reconstruction items. The purpose of the study is developing a camera calibration process with multiple 2D calibration patterns and a three dimension model with large-scale could be reconstructed by SFS method. In this study, five different calibration pattern and the corresponding decoding process were designed based on the two-dimension camera calibration, so the placement of patterns around objects could be identified. With the homography estimation method, the solid geometry of calibration patterns was obtained. All patterns of all images were integrated into a global coordinate system. Then both of external and internal parameters in each image were determined. The process mentioned above was integrated a human-machine interface program based on C# programing language. User can obtain the modeling information only by inputting the relevant information. Finally, this study chose three small-scale objects and four large-scale objects to demonstrate the reconstruction of three-dimension model for verifying the feasibility of the proposed method in this study.

Biological invasions threaten biodiversity, and understanding the factors that influence a community’s susceptibility to invasion informs both management of invasive species and conservation of biodiversity. The biotic resistance hypothesis postulates that communities with greater number of competitors, predators and/or pathogens will resist biological invasions. The underlying mechanism of biotic resistance, in the realm of competition, is that in species-rich communities harbor fewer open niches for introduced species to colonize therefore decreasing the probability of invasion. My dissertation research evaluated the role of native species diversity, as well as other biotic, abiotic and landscape factors shaping exotic species richness at multiple spatial scales in an old-field ecosystem. I found that old-field communities with greater native diversity are more invasible, having greater exotic richness, at multiple spatial scales. Additionally, I investigated the role of native species diversity, biotic and abiotic factors shaping patterns of abundance by an invasive species, Lespedeza cuneata, at multiple spatial scales. Lespedeza is a rank one invasive species in several U.S. states including Tennessee due to its potential ecological impacts. I found Lespedeza abundance to be negatively associated with the abundance of dominant species, as well as with the abundance of other N-fixing species (mostly native to North America). I then conducted two field experiments which addressed the role of dominant taxa identity, in particular, the genera Solidago and Verbesina affecting old-field community structure and invasibility by Lespedeza (i.e. establishment). The second experiment investigated the role of resource availability structuring an old-field community and early establishment by Lespedeza. Overall, my findings suggest that native species diversity, abiotic and landscape factors influence multiple spatial scales.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2008.
Title from title page screen (viewed on Sept. 10, 2009). Thesis advisor: Nathan J. Sanders. Thesis advisor: Daniel Simberloff. Vita. Includes bibliographical references.

There is a growing need to understand the deformation mechanisms in titanium alloys due to their widespread use in the aerospace industry (especially within gas turbine engines), variation in their properties and performance based on their microstructure, and their tendency to undergo premature failure due to dwell and high cycle fatigue well below their yield strength. Crystal plasticity finite element (CPFE) modeling is a popular computational tool used to understand deformation in these polycrystalline alloys. With the advancement in experimental techniques such as electron backscatter diffraction, digital image correlation (DIC) and high-energy x-ray diffraction, more insights into the microstructure of the material and its deformation process can be attained. This research leverages data from a number of experimental techniques to develop well-informed and calibrated CPFE models for titanium alloys at multiple length-scales and use them to further understand the deformation in these alloys.

The first part of the research utilizes experimental data from high-energy x-ray diffraction microscopy to initialize grain-level residual stresses and capture the correct grain morphology within CPFE simulations. Further, another method to incorporate the effect of grain-level residual stresses via geometrically necessary dislocations obtained from 2D material characterization is developed and implemented within the CPFE framework. Using this approach, grain level information about residual stresses obtained spatially over the region of interest, directly from the EBSD and high-energy x-ray diffraction microscopy, is utilized as an input to the model.

The second part of this research involves calibrating the CPFE model based upon a systematic and detailed optimization routine utilizing experimental data in the form of macroscopic stress-strain curves coupled with lattice strains on different crystallographic planes for the α and β phases, obtained from high energy X-ray diffraction experiments for multiple material pedigrees with varying β volume fractions. This fully calibrated CPFE model is then used to gain a comprehensive understanding of deformation behavior of Ti-6Al-4V, specifically the effect of the relative orientation of the α and β phases within the microstructure.

In the final part of this work, large and highly textured regions, referred to as macrozones or microtextured regions (MTRs), with sizes up to several orders of magnitude larger than that of the individual grains, found in dual phase Titanium alloys are modeled using a reduced order simulation strategy. This is done to overcome the computational challenges associated with modeling macrozones. The reduced order model is then used to investigate the strain localization within the microstructure and the effect of varying the misorientation tolerance on the localization of plastic strain within the macrozones.

INTRODUZIONE: Il presente progetto di ricerca nasce all’interno di un Dottorato Eureka, sviluppato grazie al contributo della Regione Marche, dell’Università di Macerata e dell’azienda Jobmetoo by Jobdisabili srl, agenzia per il lavoro esclusivamente focalizzata sui lavoratori con disabilità o appartenenti alle categorie protette. Se trovare lavoro è già difficile per molti, per chi ha una disabilità diventa un percorso pieno di ostacoli. Nonostante, infatti, la legge 68/99 abbia una visione tra le più avanzate in Europa, l’Italia è stata ripresa dalla Corte Europea per non rispettare i propri doveri relativamente al collocamento mirato delle persone con disabilità. Tra chi ha una disabilità, la disoccupazione è fra il 50% e il 70% in Europa, con punte dell’80% in Italia. L’attuale strategia europea sulla disabilità 2010-2020 pone come obiettivi fondamentali la lotta alla discriminazione, le pari opportunità e l’inclusione attiva. Per la realizzazione di tali obiettivi assume un’importanza centrale l’orientamento permanente: esso si esercita in forme e modalità diverse a seconda dei bisogni, dei contesti e delle situazioni. La centralità di tutti gli interventi orientativi è il riconoscimento della capacità di autodeterminazione dell’essere umano, che va supportato nel trovare la massima possibilità di manifestarsi e realizzarsi. Ciò vale ancora di più per le persone con disabilità, in quanto risultano fondamentali tutte quelle azioni che consentono loro di raggiungere una consapevolezza delle proprie capacità/abilità accanto al riconoscimento delle caratteristiche della propria disabilità. L’orientamento assume così un valore permanente nella vita di ogni persona, garantendone lo sviluppo e il sostegno nei processi di scelta e di decisione con l’obiettivo di promuovere l’occupazione attiva, la crescita economica e l’inclusione sociale. Oggi giorno il frame work di riferimento concettuale nel campo della disabilità è l’International Classification of Functioning, Disability and Health (ICF), il quale ha portato a un vero e proprio rovesciamento del termine disabilità dal negativo al positivo: non si parla più di impedimenti, disabilità, handicap, ma di funzioni, strutture e attività. In quest’ottica, la disabilità non appare più come mera conseguenza delle condizioni fisiche dell’individuo, ma scaturisce dalla relazione fra l’individuo e le condizioni del mondo esterno. In termini di progetto di vita la sfida della persona con disabilità è quella di poter essere messa nelle condizioni di sperimentarsi come attore della propria esistenza, con il diritto di poter decidere e, quindi, di agire di conseguenza in funzione del proprio benessere e della qualità della propria vita, un una logica di autodeterminazione. OBIETTIVO: Sulla base del background e delle teorie di riferimento analizzate e delle necessità aziendali è stata elaborata la seguente domanda di ricerca: è possibile aumentare la consapevolezza negli/nelle studenti/esse e laureati/e con disabilità che si approcciano al mondo del lavoro, rispetto alle proprie abilità, competenze, risorse, oltre che alle limitazioni imposte dalla propria disabilità? L’obiettivo è quello di sostenere i processi di auto-riflessione sulla propria identità e di valorizzare il ruolo attivo della persona stessa nella sua autodeterminazione, con la finalità ultima di aumentare e migliorare il match tra le persone con disabilità e le imprese. L’auto-riflessione permetterà di facilitare il successivo contatto dialogico con esperti di orientamento e costituirà una competenza che il soggetto porterà comunque come valore aggiunto nel mondo del lavoro. METODI E ATTIVITÀ: Il paradigma teorico-metodologico adottato è un approccio costruttivista: peculiarità di questo metodo è che ciascuna componente della ricerca può essere riconsiderata o modificata nel corso della sua conduzione o come conseguenza di cambiamenti introdotti in qualche altra componente e pertanto il processo è caratterizzato da circolarità; la metodologia e gli strumenti non sono dunque assoggettati alla ricerca ma sono al servizio degli obiettivi di questa. Il primo passo del progetto di ricerca è stato quello di ricostruzione dello stato dell’arte, raccogliendo dati, attraverso la ricerca bibliografica e sitografica su: l’orientamento, la normativa vigente in tema di disabilità, i dati di occupazione/disoccupazione delle persone con disabilità e gli strumenti di accompagnamento al lavoro. A fronte di dati mancanti sul territorio italiano relativi alla carriera e ai fabbisogni lavorativi degli/delle studenti/esse e laureati/e con disabilità, nella prima fase del progetto di ricerca è stata avviata una raccolta dati su scala nazionale, relativa al monitoraggio di carriera degli studenti/laureati con disabilità e all’individuazione dei bisogni connessi al mondo del lavoro. Per la raccolta dati è stato sviluppato un questionario ed è stata richiesta la collaborazione a tutte le Università italiane. Sulla base dei dati ricavati dal questionario, della letteratura e delle indagini esistenti sulle professioni, nella fase successiva della ricerca si è proceduto alla strutturazione di un percorso di auto-orientamento, volto ad aumentare la consapevolezza nelle persone con disabilità delle proprie abilità e risorse, accanto a quella dei propri limiti. In particolare, il punto di partenza per la costruzione del percorso è stata l’Indagine Istat- Isfol sulle professioni (2012) e la teoria delle Intelligenze Multiple di H. Gardner (1983). Si è arrivati così alla strutturazione del percorso di auto-orientamento, composto da una serie di questionari attraverso i quali il candidato è chiamato ad auto-valutare le proprie conoscenze, le competenze, le condizioni di lavoro che gli richiedono più o meno sforzo e le intelligenze che lo caratterizzano, aggiungendo a questi anche una parte più narrativa dove il soggetto è invitato a raccontare i propri punti di forza, debolezza e le proprie aspirazioni in ambito professionale. Per sperimentare il percorso di auto-orientamento creato, nell’ultima fase della ricerca è stato predisposto uno studio pilota per la raccolta di alcuni primi dati qualitativi con target differenti, studenti/esse universitari/e e insegnanti di scuola superiore impegnati nel tema del sostegno e dell’orientamento, e utilizzando diversi strumenti (autopresentazioni, test multidimensionale autostima, focus group). CONCLUSIONI: I dati ottenuti dallo studio pilota, seppur non generalizzabili, in quanto provenienti da un campione esiguo, hanno evidenziato come il percorso di auto-orientamento attivi una riflessione sulla visione di sé nei diversi contesti e un cambiamento, in positivo o in negativo, nell’autostima e nella valutazione di sé in diverse aree, ad esempio nell’area delle relazioni interpersonali, del vissuto corporeo, dell’emotività ecc. Tali dati ci hanno permesso soprattutto di evidenziare punti di forza e debolezza del percorso creato e di apportare modifiche per una maggiore comprensione e adattabilità del prodotto stesso. Il valore del percorso orientativo è connesso al ruolo attivo di auto-valutatore giocato dal candidato con disabilità, affiancando a questa prima fase di autovalutazione un successivo confronto dialogico con un esperto, tale da permettere un ancoraggio alla realtà esterna, al contesto in cui il soggetto si trova a vivere. In questo senso, l’orientamento assume il valore di un processo continuo e articolato, che ha come scopo principale quello di sostenere la consapevolezza di sé e delle proprie potenzialità, agendo all’interno dell’area dello sviluppo prossimale della persona verso la realizzazione della propria identità personale, sociale e professionale.