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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Pairwise Element Computation with MapReduce

Kiefer, Tim, Volk, Peter Benjamin, Lehner, Wolfgang 03 May 2022 (has links)
In this paper, we present a parallel method to evaluate functions on pairs of elements. It is a challenge to partition the Cartesian product of a set with itself in order to parallelize the function evaluation on all pairs. Our solution uses (a) replication of set elements to allow for partitioning and (b) aggregation of the results gathered for different copies of an element. Based on an execution model with nodes that execute tasks on local data without online communication, we present a generic algorithm and show how it can be implemented with MapReduce. Three different distribution schemes that define the partitioning of the Cartesian product are introduced, compared, and evaluated. Any one of the distribution schemes can be used to derive and implement a specific algorithm for parallel pairwise element computation.
62

Hundred Holiday Homes

Samuelsson, Sarah January 2022 (has links)
I have created a modular concept for holiday homes that is shared by hundred families. The concept uses simple means - to improve the quality of life for many people. My aim has been to create a system for maximizing the use of the buildings and efficiently use the benefits of sharing. To keep cost down in order to make the concept as accessible as possible for the average consumer.Therefore the materials and construction have been carefully planned in order to minimize cost at initial building process and maintenance in the long term.  Hundred Holiday Homes- is a concept that - • Makes living in nature available to people of all         economic means - Increases availability • Bring people together – Increased social exposure • Uses buildings more efficiently – Maximizes utilization  • Modular building blocks - Easier adaptation for future neeads • All this whilst reducing the environmental impact         by 71%  - Reduced footprint
63

Reliability Evaluation of Large-Area Sintered Direct Bonded Aluminum Substrates for Medium-Voltage Power Modules

Gersh, Jacob Daniel 16 June 2021 (has links)
This thesis investigates techniques for prototyping and evaluation of medium voltage (MV) power module packages. Specific focus will be given to the utilization of silver sintering as a bonding method for high temperature, high density power modules. Nano-silver paste and preform will be examined in detail as enabling technologies for a new generation of power electronics. To accomplish this task, analysis and characterization of the metal-ceramic substrate and its structure is performed. First, finite element models are created to evaluate the fatigue behavior of the large area bonds in the substrate structure. Prototypes of these multi-layer substrates have also been fabricated and will be subjected to thermal cycling tests for experimental verification of the efficacy of their sintered silver bonds. Stacked direct-bonded aluminum (DBA) substrates have been found to withstand up to 1000 thermal cycles of –40 °C to 200 °C when attached with low pressure-assisted silver sintering. The thermal performance of 10 kV SiC power module utilizing multi-layer DBA substrates bonded with a large-area, low pressure-assisted sintered silver bond will also be examined to ensure the sintered bond is viable for the harsh operating conditions of MV modules. A junction-to-case thermal resistance of 0.142 °C/W is measured on a module prototype utilizing stacked DBA substrates. Finally, analysis of a double-sided cooling scheme enabled by large area sintering is simulated and prototyped to demonstrate a 6.5 kV package for a MV power device. Residual stress failures induced by a highly rigid structure have been examined and mitigated through implementation of a 5 MPa pressure-assisted, double-sided silver sintering approach. / Master of Science / Power modules are the building blocks of the electrical grid of the future. As society transitions to renewable energy to fight the crisis presented by climate change, the structure of the energy grid will have to change to accommodate the increase in solar, wind, geothermal, and other renewable sources of energy generation. A clean energy grid structure will contain ubiquitous opportunities to use power modules for medium-voltage (MV) applications, like managing the flow of electricity from solar panels and wind turbines to neighborhoods and office buildings. However, these MV power modules will need to be resilient to extreme temperature and electrical stresses inherent to these applications. Current technology must be improved in both performance and reliability to match the needs of this future grid. This thesis investigates, through both experiment and computer simulation, techniques for improving the reliability of MV power modules without sacrificing thermal or electrical performance. Techniques presented in this work have the potential to transform power modules, so they may operate at higher temperatures and efficiencies for a longer lifetime than the current state-of-the-art.
64

Mei-A Module System for Mechanized Mathematics Systems

Xu, Jian 01 1900 (has links)
<p>This thesis presents several module systems, in particular Mei and DMei, designed for mechanized mathematics systems. Mei is a λ-calculus style module system that supports higher-order functors in a natural way. The semantics of functor application is based on substitution. A novel coercion mechanism integrates a parameter passing mechanism based on theory interpretations with simple λ-calculus style higher-order functors. DMei extends Mei by supporting dependent functor types. Mei is the first module system that successfully supports both higher-order functors and a parameter passing mechanism based on theory interpretations.</p> / Thesis / Doctor of Philosophy (PhD)
65

Difference-Based Temporal Module for Monocular Category-Level 6 DoF Object Pose Tracking

Chen, Zishen 22 January 2024 (has links)
Monocular 6DoF pose tracking has many applications in augmented reality, robotics and other areas and because of the rise of deep learning new approaches such as category-level models are successful. The temporal information in sequential data is essential for both online and offline tasks, which can help boost the quality of predictions while encountering some unexpected influences like occlusions and vibration. In 2D object detection and tracking, substantial research has been done in leveraging temporal information to improve the performance of the model. Nevertheless, it is challenging to lift the temporal processing to 3D space because of the ambiguity of the visual data. In this thesis, we propose a method to calculate the temporal difference of points and pixels assuming that the K nearest points share similar features. The extracted features from the difference are learned to weigh the relevant points in the temporal sequence and aggregate them to provide support to the current frame's prediction. We propose a novel difference-based temporal module to incorporate both RGB and 3D points data in a temporal sequence. This module can be easily integrated with any category-level 6DoF pose tracking model which uses RGB and 3D points as input. We evaluate this module on two state-of-the-art category-level 6D pose tracking models and the result shows that it can increase the model's accuracy and robustness in complex scenarios.
66

The Data, The Generic, and the Architecture

Nguyen, Levy H. 27 October 2014 (has links)
No description available.
67

A prom burner module extension card for an IBM PC

Chen, Chiung-Hsing January 1989 (has links)
No description available.
68

Multiphase Voltage Regulator Modules with Magnetic Integration to Power Microprocessors

Xu, Peng 15 March 2002 (has links)
Advances in very large scale integration (VLSI) technologies impose challenges for voltage regulator modules (VRM) to deliver high-quality power to modern microprocessors. As an enabling technology, multiphase converters have become the standard practice in VRM industry. The primary objectives of this dissertation are to develop advanced topologies and innovative integrated magnetics for high-efficiency, high-power-density and fast-transient VRMs. The optimization of multiphase VRMs has also been addressed. Today's multiphase VRMs are almost universally based on the buck topology. With increased input voltage and decreased output voltage, the multiphase buck converter suffers from a very small duty cycle and cannot achieve a desirable efficiency. The multiphase tapped-inductor buck converter is one of the simplest topologies with a decent duty cycle. However, the leakage inductance of its tapped inductors causes a severe voltage spike problem. An improved topology, named the multiphase coupled-buck converter, is proposed. This innovative topology enables the use of a larger duty cycle with clamped device voltage and recovered leakage energy. Under the same transient responses, the multiphase coupled-buck converter has a significantly better efficiency than the multiphase buck converter. By integrating all the magnetic components into a single core, in which the windings are wound around the center leg and the air gaps are placed on the two outer legs, it is possible for multiphase VRMs to further improve efficiency and cut the size and cost. Unfortunately, this structure suffers from an undesirable core structure and huge leakage inductance. An improved integrated magnetic structure is proposed to overcome these limitations. All the windings are wound around the two outer legs and the air gap is placed on the center leg. The improved structure also features the flux ripple cancellation in the center leg and strongly reverse-coupled inductors. Both core loss and winding loss are reduced. The steady-state current ripples can be reduced without compromising the transient responses. The overall efficiency of the converter is improved. The input inductor can also be integrated in the improved integrated magnetic structure. Currently, selecting the appropriate number of channels for multiphase VRMs is still an empirical trial-and-error process. This dissertation proposes a methodology for determining the right number of channels for the optimal multiphase design. The problem formulation and general method for the optimization are proposed. Two examples are performed step by step to demonstrate the proposed optimization methodology. Both are focused on typical VRM 9.0 designs for the latest Pentium 4® microprocessors and their results are compared with the industry practice. / Ph. D.
69

High-Frequency and High-Performance VRM Design for the Next Generations of Processors

Yao, Kaiwei 29 April 2004 (has links)
It is perceived that Moore's Law will prevail at least for the next decade with the continuous advancement of processing technologies for integrated circuits. According to Intel's roadmap, over one billion transistors will be integrated in one processor by the year 2010; the processor's clock speed will approach 15 GHz; the core static currents will increase up to 200 A; the dynamic current slew rate will rise up to 250 A/ns; and the core voltage will decrease to 0.8 V. The rapid advancement of processor technology has posed stringent challenges to power management for both an efficient power delivery and an accurate voltage regulation. The primary objectives of this dissertation are to understand the fundamental limitations of the state-of-the-art solution for the power management, and hence to support possible solutions for meeting the power requirement of the next generations of processors. First, today's voltage-regulator module (VRM) design, which is based on the multiphase interleaving buck topology, is thoroughly analyzed. The analysis results of the control bandwidths versus the VRM transient voltage spikes highlight the trend of high-frequency VRM design for smaller size and faster transient response. Based on the concept of achieving constant VRM output impedance, design guidelines are proposed for different kinds of control methods. However, the high switching-related losses in the conventional multiphase buck converter limit its further applications. This dissertation proposes a series of new topologies in order to break through the barriers by applying an inductor-coupling or autotransformer structure to reduce the switching-related losses by extending the duty cycle. Then, this dissertation pushes the topology innovation further by introducing soft-switching quasi-resonant converters for the VRM design. The combination of the quasi-resonant and active-clamped concepts derives a family of new converters, which can eliminate all the switching and body-diode losses. The experimental results at 1-2MHz switching frequencies prove that the proposed solutions for the VRM design can realize very high efficiency and high power density. / Ph. D.
70

Syzygy Decompositions and Projective Resolutions

Smith, Nathan A. 24 April 1999 (has links)
We give a projective resolution of a finite dimensional 𝛫-algebra 𝛬 over its enveloping algebra 𝛬<SUP>𝑒</SUP> = 𝛬<SUP>𝑜𝑝</SUP> ⨂<SUB>𝛫</SUB>𝛬. The description of this resolution is related to decompositions of the first syzygy module of 𝛬 as an 𝛬<SUP>𝑒</SUP> module. Resolutions of right 𝛬 modules 𝑀<SUB>𝛬</SUB> may be obtained by tensoring 𝑀 over 𝛬 with this bimodule resoution. We describe how to obtain such a resolution when 𝑀 is simple or when 𝑀 is given in the form of a projective presentation. Computations of <I>𝐸𝑥𝑡</I><SUB>𝛬</SUB><SUP>𝑛</SUP>(𝑆<SUB>𝑣</SUB>,𝑆<SUB>𝑤</SUB>) for certain classes of algebras 𝛬 are made using these resolutions, and applied to obtain results on global dimension. / Ph. D.

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