Design of an Adaptable Run-Time Reconfigurable Software-Defined Radio Processing Architecture

Processing power is a key technical challenge holding back the development of a high-performance software defined radio (SDR). Traditionally, SDR has utilized digital signal processors (DSPs), but increasingly complex algorithms, higher data rates, and multi-tasking needs have exceed the processing capabilities of modern DSPs. Reconfigurable computers, such as field-programmable gate arrays (FPGAs), are popular alternatives because of their performance gains over software for streaming data applications like SDR. However, FPGAs have not yet realized the ideal SDR because architectures have not fully utilized their partial reconfiguration (PR) capabilities to bring needed flexibility. A reconfigurable processor architecture is proposed that utilizes PR in reconfigurable computers to achieve a more sophisticated SDR. The proposed processor contains run-time swappable blocks whose parameters and interconnects are programmable. The architecture is analyzed for performance and flexibility and compared with available alternate technologies. For a sample QPSK algorithm, hardware performance gains of at least 44x are seen over modern desktop processors and DSPs while most of their flexibility and extensibility is maintained

Anisotropically weighted and nonholonomically constrained evolutions on manifolds

We present evolution equations for a family of paths that results from anisotropically weighting curve energies in non-linear statistics of manifold valued data. This situation arises when performing inference on data that have non-trivial covariance and are anisotropic distributed. The family can be interpreted as most probable paths for a driving semi-martingale that through stochastic development is mapped to the manifold. We discuss how the paths are projections of geodesics for a sub-Riemannian metric on the frame bundle of the manifold, and how the curvature of the underlying connection appears in the sub-Riemannian Hamilton-Jacobi equations. Evolution equations for both metric and cometric formulations of the sub-Riemannian metric are derived. We furthermore show how rank-deficient metrics can be mixed with an underlying Riemannian metric, and we relate the paths to geodesics and polynomials in Riemannian geometry. Examples from the family of paths are visualized on embedded surfaces, and we explore computational representations on finite dimensional landmark manifolds with geometry induced from right-invariant metrics on diffeomorphism groups

OPSET Program for Computerized Selection of Watershed Parameter Values for the Stanford Watershed Model

The advent of high-speed electronic computer made it possible to model complex hydrologic processes by mathematical expressions and thereby simulate streamflows from climatological data. The most widely used program is the Stanford Watershed Model, a digital parametric model of the land phase of the hydrologic cycle based on moisture accounting processes. It can be used to simulate annual or longer flow sequences at hourly time intervals. Due to its capability of simulating historical streamflows from recorded climatological data, it has a great potential in the planning and design of water resources systems. However, widespread use of the Stanford Watershed Model has been deterred by difficulties in understanding and finding a computer sufficiently large to run the bulky program. More important, the estimation of values for key parameters was both time-consuming and subjective as it had to be done by trial and error. The objective of this study is to develop a computerized parameter optimization procedure, a self-calibrating watershed model, based on the FORTRAN version of the Stanford Watershed Model known as the Kentucky Watershed Model. This computerized procedure is named OPSET because its objective is to determine an optimum set of parameter values. The basic approach of OPSET is to match synthesized flows with recorded flows. The first step is by sensitivity studies to determine which key watershed para.meters are sensitive in the simulation of flows and are difficult to measure or estimate directly. The second step is to devise a scheme for adjusting numerical estimates of the selected key parameters systematically improving flow simulation until the best possible matching is achieved and to program this scheme into a streamlined Kentucky Watershed Model. Independent adjustment schemes are used for parameters associated with simulating runoff volumes, recession flows and flood hydrograph. The third step is to empirically test and improve this self-calibrating watershed model by applying it to a number of watersheds in Kentucky. OPSET estimates selected watershed parameters on a one water year basis, and the values of parameters best describing the watershed characteristics should be averaged from several OPSET-selected one-year-based values. In applying OPSET to over 20 Kentucky watersheds which represent quite a wide range of topographic and soil conditions, this model was found to be rather successful. It is able to simulate streamflows and find more consistently estimated para.meter values than the trial-and-error approach. The time spent on calibrating the watershed parameters is greatly reduced. The user does not have to spend so much time familiarizing himself with the program before he can properly use the Model. The program uses standardized criteria which reduce the subjectivity of estimating parameter values. The recommendation is ma.de that OPSET should be applied to areas where the climatological setting and geographical conditions differ from Kentucky in order to refine and modify it for a wider range of applicability. Also, the Model itself needs periodic updating in order to take advantage of subsequent empirical relationships or moisture accounting procedures

Exploiting an alternative labeling for efficient hypercube algorithms

Ankara : Department of Computer Engineering and Information Science and Institute of Engineering and Sciences, Bilkent Univ., 1991.Thesis (Master's) -- Bilkent University, 1991.Includes bibliographical references leaves 57Aydın, CavitM.S

Is metabolism goal-directed? Investigating the validity of modeling biological systems with cybernetic control via omic data

Cybernetic models are uniquely juxtaposed to other metabolic modeling frameworks in that they describe the time-dependent regulation of cellular reactions in terms of dynamic metabolic goals. This approach contrasts starkly with purely mechanistic descriptions of metabolic regulation which seek to explain metabolic processes in high resolution — a clearly daunting undertaking. Over a span of three decades, cybernetic models have been used to predict metabolic phenomena ranging from resource consumption in mixed-substrate environments to intracellular reaction fluxes of intricate metabolic networks. While the cybernetic approach has been validated in its utility for the prediction of metabolic phenomena, its central feature, the goal-directed control strategy, has yet to be scrutinized through comparison with omic data. Ultimately, the aim of this work is to address the question Is metabolism-goal directed? through the analysis of biological data. To do so, this work investigates the idea that metabolism is goal-directed from three distinct angles. The first is to make a comparison of cybernetic models to other metabolic modeling frameworks. These mathematical formulations for intracellular chemical reaction networks range from purely mechanistic, kinetic models to linear programming approximations. Instead of comparing these frameworks directly on the basis of accuracy alone, a novel approach to systems biological model selection is developed. This approach compares models using information theoretic arguments. From this point of view, the model that compresses biological data best captures the most regularity in the data generated by a process. This framework is used to compare the flux predictions of cybernetic, constraint-based and kinetic models in several case studies. Cybernetic models, in the test cases examined, provide the most compact description of metabolic fluxes. This method of analysis can be extended to any systems biological model selection problem for the purposes of optimization and control. To further examine cybernetic control mechanisms, the second portion of this dissertation focuses on confronting cybernetic variable predictions with data that is representative of enzyme regulation. More specifically, the dynamic behavior of cybernetic variables, ui, which are representative of enzyme synthesis control are matched with gene expression data that represents the control of enzyme synthesis in cells. This comparison is made for the model system of cybernetic modeling, diauxic growth, and for prostaglandin (PG) metabolism in mammalian cells. Via analysis of these systems, a correlation between the dynamic behavior of cybernetic control variables and the true mechanisms that guide cellular regulation is discovered. Additionally, this result demonstrates potential use of cybernetic variables for the prediction of relative changes in gene expression levels. The last approach taken to test the veracity of cybernetic control is to develop a technique to mine objective functions from biological data. In this approach, returns on investment (ROIs) for various pathways are first established through simultaneous analysis of metabolite and gene expression data for a given metabolic system. Following this, the ROIs are used to determine a metabolic systems observed goal signal. Gene expression data is then mined to select genes that show expression changes that are similar to the goal signal\u27s behavior. This gene list is then analyzed to determine enriched biological pathways. In the final step, these pathways are then surveyed in the literature to establish feasible metabolic goals for the system of interest. This method is applied to analyze diauxic growth and prostaglandin systems and generates objective functions that are relevant to known properties of these metabolic networks from the literature. An enhanced understanding of metabolic goals in mammalian systems generated by this work reveals the potential utility of cybernetic modeling in new directions related to translational research. Overall, this investigation yields support of the notion of dynamic metabolic goals in cells through comparison of metabolic modeling approaches and through the analysis of omic data. From these results, a lucid argument is made for the use of goal-directed modeling approaches and a deeper understanding of the optimal nature of metabolic regulation is gained

Silicon Nanowires for Biosensor Applications

Nanostrukturen haben in den letzten Jahrzehnten durch konsequente Förderung wie der im Jahr 2000 gestarteten National Nanotechnology Initiative der USA oder des deutschen Pendants Aktionsplan Nanotechnologie erhebliches Aufsehen, nicht nur in der Wissenschaft, sondern auch in der technischen und wirtschaftlichen Umsetzung erfahren. In Kombination mit biologischen Systemen, deren Funktionalität sich auf der Größenordnung von Nanometern abspielt, finden nanotechnologische Entwicklungen auf dem Gebiet der Medizin ein großes technisches Anwendungsgebiet. Diese Arbeit widmet sich der Untersuchung und technischen Entwicklung von Siliziumnanodrähten als Sensoren für zukünftige medizinische Anwendungen. Im Gegensatz zu Sensoren die auf dotierten Nanodrähten basieren, wurden hier undotierte Nanodrähte untersucht, die mit geringerem Produktionsaufwand auskommen und mittels Schottky-Barrieren als Feldeffekttransistoren nutzbar sind. Deren Eigenschaften wurden im Hinblick auf pH und Biosensorik theoretisch und experimentell untersucht, sowie technisch in ein lab-on-chip sowie ein kompaktes Multiplexer-Messgerät integriert. In einem zweiten, separaten Teil wurden die Eigenschaften undotierter Nanodrähte für die optische Spektroskopie theoretisch modelliert. Die Inhalte beider Teile werden im folgenden kurz zusammengefasst. Um die elektrischen Sensoreigenschaften der Siliziumnanodrähte zu untersuchen, wurden zunächst Computermodelle der Drähte erstellt, mit deren Hilfe der Elektronentransport in flüssiger Umgebung quantenmechanisch modelliert wurde. Die dafür erstellten Modellvorstellungen waren für die sich daran anschließenden experimentellen Untersuchungen des Rauschverhaltens, der pH-Sensitivität sowie der Biosensoreigenschaften sehr vorteilhaft. Mit Hilfe einer neu entwickelten Messmethode konnte der optimale Arbeitspunkt der Sensoren ermittelt werden, sowie die hohe Sensorqualität mittels einer empirischen mathematischen Beschreibung des zu erwartenden Sensorsignals eingeordnet werden. Weiterhin wurden für die Medizintechnik relevante Messungen von Thrombin durchgeführt. Damit ist für den hier beschriebenen Sensortyp ein proof-of-concept für neuartige medizinische Messelemente gelungen. Um die kleinen Abmessungen der Sensoren darüber hinaus technisch nutzbar zu machen, wurden sie in ein lab-on-chip System integriert, in welchem sie als Sensoren für den pH-Wert sowie die ionische Konzentration in Nanoliter-Tropfen verwendet wurden. Desweiteren wurde in Kooperation mit dem Institut für Aufbau- und Verbindungstechnik ein portables Messgerät entwickelt, welches die parallele Messung mehrerer Nanodrahtsensoren ermöglicht. Im zweiten Teil der Arbeit wird eine theoretische Untersuchung zur Eignung von Silizium-Nanodrähten als Messsonden (Probes) für die optische Spektroskopie vorgestellt. Dazu wurde eine Methode entwickelt mittels derer es möglich ist, Raman und Infrarotspektren von Nanostrukturen mittels Molekulardynamik zu berechnen. Die Methode wurde auf undotierte Silizium-Nanodrähte augewendet und zeigt, dass die Oberflächenbeschaffenheit der Drähte die optischen Spektren entscheidend beeinflusst. Damit konnte die Relevanz von Halbeiter-Nanostrukturen auch für Anwendungen in der optischen Spektroskopie gezeigt werden.:I Introduction: Sensing with Nanostructures 1 Introduction 2 Field effect transistors as electronic sensor elements 3 Packaging: Connecting Nano and Macro 4 Nanostructures as transducers in optical spectroscopy II Electronic sensing with Schottky Barrier silicon nanowires 5 Schottky-Barrier silicon nanowire field effect transistors 6 ISFET measurement principles 7 pH and Biosensing with silicon nanowires 8 Thrombin sensing 9 Silicon nanowire FETs in a Lab-on-a-Chip device 10 Multiplexer sensing platform 11 Experimental methods III Simulating optical spectra of silicon nanowires 12 Theoretical fundamentals 13 Computational Methods 14 Results 15 Bibliography 16 AnhangNanostructures have attracted great attention not only in scientific research, but also in engineering applications during the last decades. Especially in combination with biological systems, whose complex function is controlled from nanoscale building blocks, nanotechnological developments find a huge field of applications in the medical sector. This work is dedicated to the functional understanding and technical implementation of silicon nanowires for future medical sensor applications. In contrast to doped silicon nanowire based sensors, this work is focussed on pure, undoped silicon nanowires, which have lower demands on production techniques and use Schottky-barriers as electric field detectors. The pH and biosensing capabilities of such undoped silicon nanowire field effect transistors were investigated theoretically and experimentally and further integrated in a lab-on-a-chip device as well as a small-scale multiplexer measurement device. In a second separate part, the optical sensing properties of undoped silicon nanowires were theoretically modeled. The main contents of both parts are shortly described in the following paragraphs. A multiscale model of silicon nanowire FETs to describe the charge transport in liquid surrounding in a quantum mechanical framework was developed to investigate the sensing properties of the nanowire sensors in general. The model set the basis for the understanding of the subsequent experimental investigations of noise characterization, pH sensitivity and biosensing properties. With the help of a novel gate sweeping measurement method the optimal working point of the sensors was determined and the high sensor quality could be quantified in terms of an empirical mathematical model. The sensor was then used for measurements of medically relevant concentrations of the Thrombin protein, providing a proof-of-concept for medical applications for our newly developed sensor. In order to exploit the small size of our sensors for technical applications we integrated the devices in lab-on-a-chip system with a microfluidic droplet generation module. There they were used to measure the pH and ionic concentration of droplets. Finally a portable multiplex measurement device for silicon nanowire sensors as well as other ion sensitive FETs was developed in cooperation with the IAVT at TU Dresden (Institut für Aufbau- und Verbindungstechnik). The second part of this thesis investigates the usability of silicon nanowires for optical sensor applications from a theoretical point of view. Therefore a method for the extraction of Raman and Infrared spectra from molecular dynamics simulations was developed. The method was applied to undoped silicon nanowires and shows that the surface properties of the nanowires has a significant effect on optical spectra. These results demonstrate the relevance of semiconductor nanostructures for applications in optical spectroscopy.:I Introduction: Sensing with Nanostructures 1 Introduction 2 Field effect transistors as electronic sensor elements 3 Packaging: Connecting Nano and Macro 4 Nanostructures as transducers in optical spectroscopy II Electronic sensing with Schottky Barrier silicon nanowires 5 Schottky-Barrier silicon nanowire field effect transistors 6 ISFET measurement principles 7 pH and Biosensing with silicon nanowires 8 Thrombin sensing 9 Silicon nanowire FETs in a Lab-on-a-Chip device 10 Multiplexer sensing platform 11 Experimental methods III Simulating optical spectra of silicon nanowires 12 Theoretical fundamentals 13 Computational Methods 14 Results 15 Bibliography 16 Anhan

Research and technology, 1993. Salute to Skylab and Spacelab: Two decades of discovery

A summary description of Skylab and Spacelab is presented. The section on Advanced Studies includes projects in space science, space systems, commercial use of space, and transportation systems. Within the Research Programs area, programs are listed under earth systems science, space physics, astrophysics, and microgravity science and applications. Technology Programs include avionics, materials and manufacturing processes, mission operations, propellant and fluid management, structures and dynamics, and systems analysis and integration. Technology transfer opportunities and success are briefly described. A glossary of abbreviations and acronyms is appended as is a list of contract personnel within the program areas

The design of hybrid stepping motors aided by three dimensional finite element analysis

Though the hybrid stepping motor has a long and proven history, in terms of toughness, accuracy of position and the ability to operate in open loop, motor performance improvements can still be made in terms of the physical structure of the motor's components. It is impossible to build a complete solution of the hybrid stepping motor using simple analytical functions or equivalent circuit representations. This is due to the difficulties introduced by the motor's highly non-linear three dimensional magnetic structure, of which the doubly salient tooth structure, axial magnet, and back iron all complicate the situation. However, with the recent advances in three dimensional finite element software a comprehensive study of the motor has been achieved in this thesis. This has allowed improvements to simpler two dimensional based mathematical models, which allow faster computation of the motor's electromagnetic performance. To aid modelling, novel equations which accurately model today's high permeability steels have been developed. These are shown to be more accurate than the established Jiles-Atherton method. Inductance calculations of the steel's flux paths have been comprehensively improved by the use of elliptical functions. The thesis concludes with the design of two quite individual new machines. The first dramatically improves a motor's power output, smoothness, noise levels, and resonance by modifying the tooth structure. The second uses soft magnetic composite materials to provide an isotropic path for cross lamination flux which flows in a stator's back iron. Both new designs are shown to offer a significant improvements to the high speed torque capability of the hybrid stepping motor

Astronautics and aeronautics, 1985: A chronology

This book is part of a series of annual chronologies of significant events in the fields of astronautics and aeronautics. Events covered are international as well as national, in political as well as scientific and technical areas. This series is an important reference work used by historians, NASA personnel, government agencies, and congressional staffs, as well as the media