This thesis addresses several synthesis and optimization issues for embedded control systems. Examples of such systems are automotive and avionics systems in which physical processes are controlled by embedded computers through sensor and actuator interfaces. The execution of multiple control applications, spanning several computation and communication components, leads to a complex temporal behavior that affects control quality. The relationship between system timing and control quality is a key issue to consider across the control design and computer implementation phases in an integrated manner. We present such an integrated framework for scheduling, controller synthesis, and quality optimization for distributed embedded control systems. At runtime, an embedded control system may need to adapt to environmental changes that affect its workload and computational capacity. Examples of such changes, which inherently increase the design complexity, are mode changes, component failures, and resource usages of the running control applications. For these three cases, we present trade-offs among control quality, resource usage, and the time complexity of design and runtime algorithms for embedded control systems. The solutions proposed in this thesis have been validated by extensive experiments. The experimental results demonstrate the efficiency and importance of the presented techniques.

Cette thèse est dédiée à l'analyse de stabilité des systèmes à pas d'échantillonnage variable et à la commande dynamique de l'échantillonnage. L'objectif est de concevoir des lois d'échantillonnage permettant de réduire la fréquence d'actualisation de la commande par retour d'état, tout en garantissant la stabilité du système.Tout d'abord, un aperçu des récents défis et axes de recherche sur les systèmes échantillonnés est présenté. Ensuite, une nouvelle approche de contrôle dynamique de l'échantillonnage, "échantillonnage dépendant de l'état", est proposée. Elle permet de concevoir hors-ligne un échantillonnage maximal dépendant de l'état défini sur des régions coniques de l'espace d'état, grâce à des LMIs.Plusieurs types de systèmes sont étudiés. Tout d'abord, le cas de système LTI idéal est considéré. La fonction d'échantillonnage est construite au moyen de polytopes convexes et de conditions de stabilité exponentielle de type Lyapunov-Razumikhin. Ensuite, la robustesse vis-à-vis des perturbations est incluse. Plusieurs applications sont proposées: analyse de stabilité robuste vis-à-vis des variations du pas d'échantillonnage, contrôles event-triggered et self-triggered, et échantillonnage dépendant de l'état. Enfin, le cas de système LTI perturbé à retard est traité. La construction de la fonction d'échantillonnage est basée sur des conditions de stabilité L2 et sur un nouveau type de fonctionnelles de Lyapunov-Krasovskii avec des matrices dépendant de l'état. Pour finir, le problème de stabilisation est traité, avec un nouveau contrôleur dont les gains commutent en fonction de l'état du système. Un co-design contrôleur/fonction d'échantillonnage est alors proposé

In daily activities, hand use is dominated by individuated thumb and finger movements, and by grasping. This thesis focused on the level of ???independence??? of the digits and its relationship to hand grasps, from the level of the motor units to the level of synergistic grasping forces. Four major studies were conducted in healthy adult volunteers. First, spike-triggered averages of forces produced by single motor units in flexor pollicis longus (FPL) in a grasp posture showed small but significant loading of the index, but not other fingers. This reflected a neural rather than anatomical coupling, as intramuscular stimulation produced minimal effect in any finger. Also, FPL had a surprisingly large number of low-force motor units and this may account for the thumb???s exceptional dexterity and force stability compared with the fingers. Second, independent control of extensor digitorum (ED) was more limited than flexor digitorum profundus (FDP), as more ED motor units of a ???test??? finger were recruited inadvertently by extension than by flexion of adjacent digits. Third, ???force enslavement??? in maximal voluntary tasks was greater in digit extension than flexion. The distribution of force enslavement (and deficits) matched the pattern of daily use of the digits (alone and in combination), and reveals a neural control system which preferentially lifts fingers together from an object by extension but allows an individual digit to flex to contact an object so the finger pads can engage in exploration and grasping. Finally, during grasping, irrespective of whether a digit had been lifted from the object, coherence among forces generated by the digits was similar. In addition, the coherence between finger forces was independent of any contraction of the thumb, was stable over 2 months, and required no learning. The pattern of coherence between digital grasping forces may be closely related to the level of digit independence and daily use. Overall, the grasp synergy was remarkably invariant over the various tasks and over time. In summary, this thesis demonstrates novel aspects of the properties of FPL, the lack of complete independence of the digits, and robustness in the production of flexion forces in hand grasps.

Three-fifths of the Earth’s crust has been built at oceanic spreading centres in the last 160 million years. To explore crustal extension processes and the architecture of these constructive plate boundaries I have studied the oceanic rift in Iceland. Here the Mid Atlantic Ridge is anomalously elevated above sea level and thus easier to instrument. I have deployed and operated a dense network of seismometers in the remote volcanic highlands in central Iceland, and used the passive seismic data collected from this network to explore crustal structure and volcanic processes in the extensional rift zones. My analysis of persistent seismicity located in an intervening region between individual spreading segments, uniquely records the segmentation of plate spreading on the scale of individual volcanic systems. Precise location and characterisation of micro-earthquakes identifies a series of faults subparallel to the rift fabric, and source mechanisms define left-lateral strike-slip motion on these faults. This extremely high quality microseismic data reveals transform motion being accommodated by bookshelf faulting in a concentrated region between two such volcanic systems, providing evidence for the localisation of spreading in the discrete volcanic systems. While transform motion between spreading centres appears to be accommodated on a continuous basis, the extension of the brittle upper crust within the spreading centres occurs episodically during rifting events. Our local seismic network fortuitously recorded such a rifting episode in August 2014, during which the opening of a 5 metre wide dyke triggered a huge increase in seismicity across large areas of the rift zone. Stress-seismicity-rate modelling of this triggered seismicity, along with geodetic constraints on the deformation, provided a remarkable opportunity with which it was possible to prove the existence of stress-shadowing, a challenge which has eluded earthquake seismologists for decades. Using the excellent coverage of our extended seismic network I have also generated a new high resolution image of the regional crustal seismic structure using surface waves extracted from ambient seismic noise. The structure reveals low seismic velocities which are closely correlated with the volcanic rift zones, and faster wavespeeds in the older and non-volcanically active Tertiary crust. The strongest anomalies are seen in the north-west of the Vatnajökull icecap, at the location of thickest crust and inferred centre of the underlying mantle plume. Inversion for shear wave velocity structure shows high velocity-gradients in the top 10 km, defining a thickened extrusive upper crust in Iceland compared to standard oceanic crust, where it is normally 2–3 km thick. Below this, the shear wave velocity structure reveals a distinct low-velocity zone in the mid crust between 14–20 km depth, which is widespread across Iceland and shallows into the active volcanic rifts. This extensive feature suggests high mid-crustal temperatures and a high temperature-gradient between the extrusives of the upper crust and the intrusive mid-to-lower crust in Iceland.

This thesis examines how to find the best fit to a series of data points when curve fitting using power-exponential models. We describe the different numerical methods such as the Gauss-Newton and Levenberg-Marquardt methods to compare them for solving non-linear least squares of curve fitting using different power-exponential functions. In addition, we show the results of numerical experiments that illustrate the effectiveness of this approach.Furthermore, we show its application to the practical problems by using different sets of data such as death rates and rocket-triggered lightning return strokes based on the transmission line model.

Abstract The multiple-input multiple-output (MIMO) technique combined with an orthogonal frequency division multiplexing (MIMO--OFDM) has been introduced as a promising approach for the ever increasing capacity and quality of service (QoS) requirements for wireless communication systems. An efficient radio spectrum utilization expects a flexible transceiver solution, which has been the reason for the development of the software defined radio (SDR) technologies which in their turn are expected to enable the creation of cognitive radios. As a result, any radio solution could be invoked on demand on any platform. In this thesis work, we have studied detector algorithms and programmable processor architectures in order to find practical solutions for the future wireless systems. A programmable receiver can reduce the energy dissipation of the receiver by changing the detection algorithm based on the current channel realizations. To provide a realistic aspect to the implementations in different channel realizations, we present a wide state-of-the-art detector comparison. In addition, we present an extensive number arithmetic and word length study in order to evaluate realistic hardware complexity and energy dissipations of the implementations. The study includes a comprehensive design chain from the algorithm development to the actual processor design and finally programming software for the platforms. We evaluate single and multi-core processor implementations by comparing the achieved results to the Long Term Evolution (LTE) performance requirements. We implement detectors on digital signal processors (DSPs), graphics processing unit (GPU) and transport triggered architecture (TTA). The implementation results are compared in throughput, silicon area and energy efficiency. Finally, we discuss the advantages and disadvantages of the architectures and the implementation effort. / Tiivistelmä Usean antennin tekniikka yhdistettynä ortogonaaliseen taajuusvaihtelumodulointiin lähetin-vastaanotimessa on esitetty eräänä lupaavana ratkaisuna jatkuvasti kasvaviin kapasiteetti- ja palvelunlaatuvaatimuksiin langattomissa tietoliikennejärjestelmissä. Tehokas radiospektrin käyttö edellyttää joustavaa lähetin-vastaanotinratkaisua, mikä on ollut syynä ohjelmistoradioteknologioiden kehitykselle. Ohjelmistoradioiden kehityksen on puolestaan odotettu mahdollistavan kognitiiviradioiden syntymisen. Tuloksena, mikä tahansa radiosovellus voitaisiin herättää tarpeen mukaan millä tahansa ohjelmoitavalla sovellusalustalla. Tässä väitöskirjatyössä tutkitaan ilmaisinalgoritmeja sekä ohjelmoitavia prosessoriarkkitehtuureja tarkoituksena löytää käytännöllisiä ratkaisuja tulevaisuuden langattomiin järjestelmiin. Ohjelmoitavalla vastaanottimella voidaan vähentää vastaanottimen energiankulutusta vaihtamalla ilmaisinalgoritmeja vallitsevan kanavatilan mukaan. Työssä esitellään laaja, viimeisintä tutkimusta edustava ilmaisinalgoritmivertailu, joka antaa realistisen näkökannan toteutuksiin erilaisissa kanavatiloissa. Lisäksi työssä esitellään numeroaritmetiikka- ja sananpituustutkimus, jonka tarkoituksena on arvioida toteutusten realistista kovokompleksisuutta sekä energiankulutusta. Tutkimus sisältää kattavan suunnitteluketjun algoritmikehityksestä todelliseen prosessorisuunnitteluun ja lopulta algoritmin ohjelmointiin tietylle sovellusalustalle. Väitöskirjatyössä arvioidaan yksi- ja moniytimisiä prosessoritoteutuksia vertaamalla saavutettuja tuloksia Long Term Evolution -standardin suorituskykyvaatimuksiin. Ilmaisimia toteutetaan digitaalisilla signaaliprosessoreilla, grafiikkaprosessorilla sekä siirtoliipaisuarkkitehtuurilla. Toteutustuloksia vertaillaan laskentatehona, pinta-alana sekä energiatehokkuutena. Lopuksi käsitellään arkkitehtuurien hyviä ja huonoja puolia sekä suunnittelun työläyttä.

This thesis presents an investigation into the factors affecting the morphology of hybrid inorganic/organic photoactive layers used in photovoltaic cells. Although optimisation of the organic (polymer) phase has received substantial attention, research into the morphology of the inorganic phase (semiconducting nanocrystals) remains limited. It is believed that there is a strong link between the morphology of the final photoactive film and the quality of the initial nanocrystal dispersion. To this end, two nanocrystal systems were investigated; zinc oxide (ZnO) and lead sulphide (PbS). ZnO nanocrystals were synthesised and found to possess reproducible characteristics. It was determined that colloid stability was initially dependent upon the presence of acetate groups bound to the surface, which in turn required a small quantity of methanol to be present in the organic dispersant. It was also discovered that while methanol evaporated readily from the surface of the nanocrystals, another molecule, 1-propylamine (1-PA), did not. Further investigations showed that while methanol only weakly physisorbed to the surface of ZnO nanocrystals, 1-PA formed strong, dative covalent bonds with Zn2+, preventing evaporation despite a low boiling point. Subsequent investigations into the effects of different ligands upon colloid stability found that amine-based groups typically possessed superior stabilising capabilities compared to alcohol-based analogues. The characteristics of nanocrystal / polymer blends were also investigated. It was determined that the nanocrystal dispersion became unstable at higher concentrations of polymer due to depletion aggregation. Films of nanocrystal / polymer blends were cast from dispersions containing either alcohol or amine-based ligands, and it was observed that dispersions stabilised with 1-PA possessed smooth morphologies on the micrometer scale. Investigations at the nanometer scale, however, revealed aggregates large enough to favour recombination.The latter half of this thesis regards the characterisation of PbS nanocrystals and investigations into triggered aggregation. It was determined that while PbS nanocrystals possessed reproducible characteristics, the stabilising molecule, oleic acid (OA) was insulating. The effects of exchanging the OA groups for a shorter ligand, butylamine (BA) were investigated.Finally, PbS nanocrystals were treated with a bidentate ligand, 1,2-ethanedithiol (EDT) to induce triggered aggregation. It was observed that the system was highly sensitive to the concentration of EDT in dispersion, forming small, relatively dispersed aggregates at low [EDT], and micrometer-sized crystalline structures at high [EDT]. The characterisation and entrapment of these nanocrystal structures within semi-conducting polymer films is also discussed.

No description available.

V této práci je navrhnut energeticky úsporný procesor typu TTA (Transport Triggered Architecture) pro výpočet rychlé Fourierovy transformace (FFT). Návrh procesoru byl vytvořen na míru použitému algoritmu pomocí speciáoních funkčních jednotek. Algoritmus byl realizován jako posloupnost instrukcí tak, že většina výpočtu probíhá ve smyčce obrahující pouze jedionu paralelní instrukci. Tato instrukce je umístěna do instrukčního bufferu, odkud je potom volána místo instrukční paměti. Díky tomu se dá docílit nižší spotřeby, neboť volání z instrukčního bufferu je efektivnější než volání z instrukční paměti. Program byl zkompilován na časovém modelu procesoru a časová simulace potvrdila správnost návrhu. Součástí práce jsou rovněž pomocné programy v Pythonu, které slouží ke generaci referenčních výsledků a automatické simulaci a porovnání výsledků simulace s referencí.

付記する学位プログラム名: グローバル生存学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20340号 / 工博第4277号 / 新制||工||1662(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 角 哲也, 准教授 佐山 敬洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM