23 research outputs found
Stable cheapest nonconforming finite elements for the Stokes equations
We introduce two pairs of stable cheapest nonconforming finite element space
pairs to approximate the Stokes equations. One pair has each component of its
velocity field to be approximated by the nonconforming quadrilateral
element while the pressure field is approximated by the piecewise constant
function with globally two-dimensional subspaces removed: one removed space is
due to the integral mean--zero property and the other space consists of global
checker--board patterns. The other pair consists of the velocity space as the
nonconforming quadrilateral element enriched by a globally
one--dimensional macro bubble function space based on
(Douglas-Santos-Sheen-Ye) nonconforming finite element space; the pressure
field is approximated by the piecewise constant function with mean--zero space
eliminated. We show that two element pairs satisfy the discrete inf-sup
condition uniformly. And we investigate the relationship between them. Several
numerical examples are shown to confirm the efficiency and reliability of the
proposed methods
Scale-invariant Bayesian Neural Networks with Connectivity Tangent Kernel
Explaining generalizations and preventing over-confident predictions are
central goals of studies on the loss landscape of neural networks. Flatness,
defined as loss invariability on perturbations of a pre-trained solution, is
widely accepted as a predictor of generalization in this context. However, the
problem that flatness and generalization bounds can be changed arbitrarily
according to the scale of a parameter was pointed out, and previous studies
partially solved the problem with restrictions: Counter-intuitively, their
generalization bounds were still variant for the function-preserving parameter
scaling transformation or limited only to an impractical network structure. As
a more fundamental solution, we propose new prior and posterior distributions
invariant to scaling transformations by \textit{decomposing} the scale and
connectivity of parameters, thereby allowing the resulting generalization bound
to describe the generalizability of a broad class of networks with the more
practical class of transformations such as weight decay with batch
normalization. We also show that the above issue adversely affects the
uncertainty calibration of Laplace approximation and propose a solution using
our invariant posterior. We empirically demonstrate our posterior provides
effective flatness and calibration measures with low complexity in such a
practical parameter transformation case, supporting its practical effectiveness
in line with our rationale
Fabrication par imprégnation directe et assemblage par soudage de composites thermoplastiques structuraux à renfort textile en fibres végétales
National audience* DĂ©veloppement dâune technique originale d'imprĂ©gnation directe de renforts continus de lin par des thermoplastiques totalement ou partiellement bio-sourcĂ©s, par injection dans un moule fermĂ©* Ătude multi-Ă©chelles des mĂ©canismes d'imprĂ©gnation / gonflement sous contraintes thermo-hydromĂ©caniques des fibres vĂ©gĂ©tales. DĂ©duction des Ă©volutions de propriĂ©tĂ©s physiques et mĂ©caniques* Ătude des mĂ©canismes dâimprĂ©gnation de composites moulĂ©s Ă haute cadence avec des thermoplastiques mono- ou bi-composants de haute fluiditĂ©* Assemblage de piĂšces composites renforcĂ©es de fibres vĂ©gĂ©tales par soudage laser* Qualification de la rĂ©sistance des joints de soudure des composites thermoplastiques bio-sourcĂ©
Low power mixed signal system design environment using floating-gate FPAAs
The objective of this research is to create a low-power mixed-signal system design environment using FG FPAAs. To achieve this, my research focused on implementing a compact hardware, developing algorithms and tools, and establishing a solid calibration flow. The first phase, implementing a compact hardware, involved developing FG SoC FPAAs including an FG programming infrastructure and built-in self test circuits, as well as designing smaller test boards to enable IoT embedded applications. Secondly, FG FPAA systems need to provide interfacing tools for application designers. This required a synthesis toolset generating a switch list from the user's design and an FG programming algorithm compatible with the SoC FPAAs. Lastly, a solid calibration flow solved the variation problem of each IC, which has been an issue in typical analog system designs. By coordinating the development of these three phases, it has been enabled to provide a powerful low-power system design environment, where system engineers consider analog circuits as black boxes, so they can enjoy the design and implementation of higher level applications, as if they are designing digital systems.Ph.D
Performance Analysis of OFDM Systems with Carrier Frequency Offset
orthogonal frequency division multiplexing (OFDM), carrier frequency offset (CFO), probability density function (PDF)prohibitionAbstract i
List of contents iii
List of figures vi
I. INTRODUCTION 1
II. SIGNAL MODEL 3
III. EXACT PDF EXPRESSION 5
3.1 BPSK Modulation 5
3.1.1 I-Q & Amplitude and Phase Distribution 5
3.1.2 SER with Frequency Offsets 10
3.2 QPSK Modulation 11
3.2.1 I-Q & Amplitude and Phase Distribution 11
3.2.2 SER with Frequency Offsets 14
3.3 16-QAM Modulation 14
3.3.1 I-Q & Amplitude and Phase Distribution 14
3.3.2 SER with Frequency Offsets 18
IV. DISCUSSION 20
V. CONCLUSION 24
APPENDIX 25
BIBLIOGRAPHY 28MasterdCollectio
A Study on the Measurement of Unregulated Pollutants in Korean Residential Environments
This study investigated the pollution caused by unregulated chemical substances in Korean residential environments. A TA tube was used for indoor air collection, and Gas ChromatographyâMass Spectrometry was used for the analysis of chemical substances. According to the results of this study, 13 substances out of the 16 analyzed chemicals were detected and, among them, the concentrations of phenol, α-pinene, and limonene within the indoor air were high. The average concentration of phenol was 32.7 ”g/m3. α-pinene and limonene were detected, of which the highest concentrations were as 598.2 ”g/m3 and 652.5 ”g/m3, respectively. The maximum concentrations of these three substances exceeded the levels of the lowest concentration of interest. Notably, α-pinene and limonene were released from the wood itself. Wood has been widely used indoors as a natural building material and as furniture. Therefore, it was considered that this was the reason for the high the concentrations of the two substances in indoor air. However, we do not argue that the usage of wood should be reduced because of the results obtained in this study. Instead, we s”ggest that it is important to reduce the emissions of α-pinene and limonene thro”gh the processing of the wood, extending its drying period, and determining the most appropriate time of use
Scaling Floating-Gate Devices Predicting Behavior for Programmable and Configurable Circuits and Systems
This paper presents scaling of Floating-Gate (FG) devices, and the resulting implication to large-scale Field Programmable Analog Arrays (FPAA) systems. The properties of FG circuits and systems in one technology (e.g., 350 nm CMOS) are experimentally shown to roughly translate to FG circuits in scaled down processes in a way predictable through MOSFET physics concepts. Scaling FG devices results in higher frequency response, (e.g., FPAA fabric) as well as lower parasitic capacitance and lower power consumption. FPAA architectures, limited to 50â100 MHz frequency ranges could be envisioned to operate at 500 MHzâ1 GHz for 130 nm line widths, and operate around 4 GHz for 40 nm line widths
Enabling Energy-Efficient Physical Computing through Analog Abstraction and IP Reuse
This paper shows the first step in analog (and mixed signal) abstraction utilized in large-scale Field Programmable Analog Arrays (FPAA), encoded in the open-source SciLab/Xcos based toolset. Having any opportunity of a wide-scale utilization of ultra-low power technology both requires programmability/reconfigurability as well as abstractable tools. Abstraction is essential both make systems rapidly, as well as reduce the barrier for a number of users to use ultra-low power physical computing techniques. Analog devices, circuits, and systems are abstractable and retain their energy efficient opportunities compared with custom digital hardware. We will present the analog (and mixed signal) abstraction developed for the open-source toolkit used for the SoC FPAAs. Abstraction of Blocks in the FPAA block library makes the SoC FPAA ecosystem accessible to system-level designers while still enabling circuit designers the freedom to build at a low level. Multiple working test cases of various levels of complexity illustrate the analog abstraction capability. The FPAA block library provides a starting point for discussing the fundamental block concepts of analog computational approaches