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 $P_1$ 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 $P_1$ nonconforming quadrilateral element enriched by a globally one--dimensional macro bubble function space based on $DSSY$ (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* Développement d’une technique originale d'imprégnation directe de renforts continus de lin par des thermoplastiques totalement ou partiellement bio-sourcés, par injection dans un moule fermé* Étude multi-échelles des mécanismes d'imprégnation / gonflement sous contraintes thermo-hydromécaniques des fibres végétales. Déduction des évolutions de propriétés physiques et mécaniques* Étude des mécanismes d’imprégnation de composites moulés à haute cadence avec des thermoplastiques mono- ou bi-composants de haute fluidité* Assemblage de pièces composites renforcées de fibres végétales par soudage laser* Qualification de la résistance des joints de soudure des composites thermoplastiques bio-sourcé

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 Chromatography–Mass 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 µg/m3. α-pinene and limonene were detected, of which the highest concentrations were as 598.2 µg/m3 and 652.5 µg/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 sµggest that it is important to reduce the emissions of α-pinene and limonene throµgh 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 50–100 MHz frequency ranges could be envisioned to operate at 500 MHz–1 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