12,216 research outputs found
An Intelligent Auxiliary Vacuum Brake System
The purpose of this paper focuses on designing an intelligent, compact, reliable, and robust auxiliary vacuum brake system (VBS) with Kalman filter and self-diagnosis scheme. All of the circuit elements in the designed system are integrated into one programmable system-on-chip (PSoC) with entire computational algorithms implemented by software. In this system, three main goals are achieved: (a) Kalman filter and hysteresis controller algorithms are employed within PSoC chip by software to surpass the noises and disturbances from hostile surrounding in a vehicle. (b) Self-diagnosis scheme is employed to identify any breakdown element of the auxiliary vacuum brake system. (c) Power MOSFET is utilized to implement PWM pump control and compared with relay control. More accurate vacuum pressure control has been accomplished as well as power energy saving. In the end, a prototype has been built and tested to confirm all of the performances claimed above
Asymmetric Adjustments in the Ethanol and Grains Markets
This paper examines the long- and short-run asymmetric adjustments for nine pairs of spot and futures prices, itemized as three own pairs for three different bio-fuel ethanol types, three own pairs for three related agricultural products, namely corn, soybeans and sugar, and three cross pairs that included hybrids of the spot price of each of the agricultural products and an ethanol futures price. Most of the spreads’ asymmetric adjustments generally happen during narrowing. The three ethanol pairs that contain the eCBOT futures with each of Chicago spot, New York Harbor spot and Western European (Rotterdam) spot show different long-run adjustments, arbitrage profitable opportunities and price risk hedging capabilities. The asymmetric spread adjustments for the three grains are also different, with corn spread showing the strongest long-run widening adjustment, and sugar showing the weakest narrowing adjustment. Among others, the empirical analysis indicates the importance of potentially hedging the spot prices of agricultural commodities with ethanol futures contracts, which sends an important message that the ethanol futures market is capable of hedging price risk in agricultural commodity markets. The short-run asymmetric adjustments for individual prices in the nine pairs (with exception of the corn own pair underscore the importance of futures prices in the price discovery and hedging potential, particularly for ethanol futures.Long-run and short-run asymmetric adjustments; ethanol; agricultural products; arbitrage opportunities; hedging; widening and narrowing adjustment
Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623A
We present detailed analysis of high-resolution C18O (2-1), SO (88-77), CO
(3-2) and DCO+ (3-2) data obtained by the Atacama Large
Millimeter/sub-millimeter Array (ALMA) towards a Class 0 Keplerian circumbinary
disk around VLA1623A, which represents one of the most complete analysis
towards a Class 0 source. From the dendrogram analysis, we identified several
accretion flows feeding the circumbinary disk in a highly anisotropic manner.
Stream-like SO emission around the circumbinary disk reveals the complicated
shocks caused by the interactions between the disk, accretion flows and
outflows. A wall-like structure is discovered south of VLA1623B. The discovery
of two outflow cavity walls at the same position traveling at different
velocities suggests the two outflows from both VLA1623A and VLA1623B overlays
on top of each other in the plane of sky. Our detailed flat and flared disk
modeling shows that Cycle 2 C18O J = 2-1 data is inconsistent with the combined
binary mass of 0.2 Msun as suggested by early Cycle 0 studies. The combined
binary mass for VLA1623A should be modified to 0.3 ~ 0.5 Msun.Comment: 26 pages, 20 figures, accepted by ApJ 2020.2.2
Identifiability of the Simplex Volume Minimization Criterion for Blind Hyperspectral Unmixing: The No Pure-Pixel Case
In blind hyperspectral unmixing (HU), the pure-pixel assumption is well-known
to be powerful in enabling simple and effective blind HU solutions. However,
the pure-pixel assumption is not always satisfied in an exact sense, especially
for scenarios where pixels are heavily mixed. In the no pure-pixel case, a good
blind HU approach to consider is the minimum volume enclosing simplex (MVES).
Empirical experience has suggested that MVES algorithms can perform well
without pure pixels, although it was not totally clear why this is true from a
theoretical viewpoint. This paper aims to address the latter issue. We develop
an analysis framework wherein the perfect endmember identifiability of MVES is
studied under the noiseless case. We prove that MVES is indeed robust against
lack of pure pixels, as long as the pixels do not get too heavily mixed and too
asymmetrically spread. The theoretical results are verified by numerical
simulations
Pentacene-Based Thin-Film Transistors With a Solution-Process Hafnium Oxide Insulator
Abstract—Pentacene-based organic thin-film transistors with
solution-process hafnium oxide (HfOx) as gate insulating layer
have been demonstrated. The solution-process HfOx could not
only exhibit a high-permittivity (κ = 11) dielectric constant but
also has good dielectric strength. Moreover, the root-mean-square
surface roughness and surface energy (γs) on the surface of the
HfOx layer were 1.304 nm and 34.24 mJ/cm2, respectively. The
smooth, as well as hydrophobic, surface of HfOx could facilitate
the direct deposition of the pentacene film without an additional
polymer treatment layer, leading to a high field-effect mobility of
3.8 cm2/(V · s).
Index Terms—Hafnium oxide, high permittivity, organic thinfilm transistor (OTFT), solution process, surface energy
Volatility Spillovers between Energy and Agricultural Markets: A Critical Appraisal of Theory and Practice
Energy and agricultural commodities and markets have been examined extensively, albeit separately, for a number of years. In the energy literature, the returns, volatility and volatility spillovers (namely, the delayed effect of a returns shock in one asset on the subsequent volatility or covolatility in another asset), among alternative energy commodities, such as oil, gasoline and ethanol across different markets, have been analysed using a variety of univariate and multivariate models, estimation techniques, data sets, and time frequencies. A similar comment applies to the separate theoretical and empirical analysis of a wide range of agricultural commodities and markets. Given the recent interest and emphasis in bio-fuels and green energy, especially bio-ethanol, which is derived from a range of agricultural products, it is not surprising that there is a topical and developing literature on the spillovers between energy and agricultural markets. Modelling and testing spillovers between the energy and agricultural markets has typically been based on estimating multivariate conditional volatility models, specifically the Baba, Engle, Kraft, and Kroner (BEKK) and dynamic conditional correlation (DCC) models. A serious technical deficiency is that the Quasi-Maximum Likelihood Estimates (QMLE) of a Full BEKK matrix, which is typically estimated in examining volatility spillover effects, has no asymptotic properties, except by assumption, so that no valid statistical test of volatility spillovers is possible. Some papers in the literature have used the DCC model to test for volatility spillovers. However, it is well known in the financial econometrics literature that the DCC model has no regularity conditions, and that the QMLE of the parameters of DCC has no asymptotic properties, so that there is no valid statistical testing of volatility spillovers. The purpose of the paper is to evaluate the theory and practice in testing for volatility spillovers between energy and agricultural markets using the multivariate Full BEKK and DCC models, and to make recommendations as to how such spillovers might be tested using valid statistical techniques. Three new definitions of volatility and covolatility spillovers are given, and the different models used in empirical applications are evaluated in terms of the new definitions and statistical criteria
Domain Specific Approximation for Object Detection
There is growing interest in object detection in advanced driver assistance
systems and autonomous robots and vehicles. To enable such innovative systems,
we need faster object detection. In this work, we investigate the trade-off
between accuracy and speed with domain-specific approximations, i.e.
category-aware image size scaling and proposals scaling, for two
state-of-the-art deep learning-based object detection meta-architectures. We
study the effectiveness of applying approximation both statically and
dynamically to understand the potential and the applicability of them. By
conducting experiments on the ImageNet VID dataset, we show that
domain-specific approximation has great potential to improve the speed of the
system without deteriorating the accuracy of object detectors, i.e. up to 7.5x
speedup for dynamic domain-specific approximation. To this end, we present our
insights toward harvesting domain-specific approximation as well as devise a
proof-of-concept runtime, AutoFocus, that exploits dynamic domain-specific
approximation.Comment: 6 pages, 6 figures. Published in IEEE Micro, vol. 38, no. 1, pp.
31-40, January/February 201
Volatility Spillovers between Energy and Agricultural Markets: A Critical Appraisal of Theory and Practice
Energy and agricultural commodities and markets have been examined extensively, albeit separately, for a number of years. In the energy literature, the returns, volatility and volatility spillovers (namely, the delayed effect of a returns shock in one asset on the subsequent volatility or covolatility in another asset), among alternative energy commodities, such as oil, gasoline and ethanol across different markets, have been analysed using a variety of univariate and multivariate models, estimation techniques, data sets, and time frequencies. A similar comment applies to the separate theoretical and empirical analysis of a wide range of agricultural commodities and markets. Given the recent interest and emphasis in bio-fuels and green energy, especially bio-ethanol, which is derived from a range of agricultural products, it is not surprising that there is a topical and developing literature on the spillovers between energy and agricultural markets. Modelling and testing spillovers between the energy and agricultural markets has typically been based on estimating multivariate conditional volatility models, specifically the Baba, Engle, Kraft, and Kroner (BEKK) and dynamic conditional correlation (DCC) models. A serious technical deficiency is that the Quasi-Maximum Likelihood Estimates (QMLE) of a Full BEKK matrix, which is typically estimated in examining volatility spillover effects, has no asymptotic properties, except by assumption, so that no valid statistical test of volatility spillovers is possible. Some papers in the literature have used the DCC model to test for volatility spillovers. However, it is well known in the financial econometrics literature that the DCC model has no regularity conditions, and that the QMLE of the parameters of DCC has no asymptotic properties, so that there is no valid statistical testing of volatility spillovers. The purpose of the paper is to evaluate the theory and practice in testing for volatility spillovers between energy and agricultural markets using the multivariate Full BEKK and DCC models, and to make recommendations as to how such spillovers might be tested using valid statistical techniques. Three new definitions of volatility and covolatility spillovers are given, and the different models used in empirical applications are evaluated in terms of the new definitions and statistical criteria
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