9,860 research outputs found
The consistency of estimator under fixed design regression model with NQD errors
In this article, basing on NQD samples, we investigate the fixed design
nonparametric regression model, where the errors are pairwise NQD random
errors, with fixed design points, and an unknown function. Nonparametric
weighted estimator will be introduced and its consistency is studied. As
special case, the consistency result for weighted kernel estimators of the
model is obtained. This extends the earlier work on independent random and
dependent random errors to NQD case
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Calibrating Large-area Mask Projection Stereolithography for Its Accuracy and Resolution Improvements
Solid freeform fabrication (SFF) processes based on mask image projection such as digital
micro-mirror devices (DMD) have the potential to be fast and inexpensive. More and more research
and commercial systems have been developed based on such digital devices. However, a digital light
processing (DLP) projector based on DMD has limited resolution and certain image blurring. In order
to use a DLP projector in the large-area mask projection stereolithography, it is critical to plan mask
images in order to achieve high accuracy and resolution. Based on our previous work on optimized
pixel blending, we present a calibration method for capturing the non-uniformity of a projection image
by a low cost off-the-shelf DLP projector. Our method is based on two calibration systems, a
geometric calibration system that can calibrate the position, shape, size, and orientation of a pixel and
an energy calibration system that can calibrate the light intensity of a pixel. Based on both results, the
light intensity at various grayscale levels can be approximated for each pixel. Developing a library of
such approximation functions is critical for the optimized pixel blending to generate a better mask
image plan. Experimental results verify our calibration results.Mechanical Engineerin
High-order soliton solutions and their dynamics in the inhomogeneous variable coefficients Hirota equation
A series of new soliton solutions are presented for the inhomogeneous
variable coefficient Hirota equation by using the Riemann Hilbert method and
transformation relationship. First, through a standard dressing procedure, the
N-soliton matrix associated with the simple zeros in the Riemann Hilbert
problem for the Hirota equation is constructed. Then the N-soliton matrix of
the inhomogeneous variable coefficient Hirota equation can be obtained by a
special transformation relationship from the N-soliton matrix of the Hirota
equation. Next, using the generalized Darboux transformation, the high-order
soliton solutions corresponding to the elementary high-order zeros in the
Riemann Hilbert problem for the Hirota equation can be derived. Similarly,
employing the transformation relationship mentioned above can lead to the
high-order soliton solutions of the inhomogeneous variable coefficient Hirota
equation. In addition, the collision dynamics of Hirota and inhomogeneous
variable coefficient Hirota equations are analyzed; the asymptotic behaviors
for multi-solitons and long-term asymptotic estimates for the high-order
one-soliton of the Hirota equation are concretely calculated. Most notably, by
analyzing the dynamics of the multi-solitons and high-order solitons of the
inhomogeneous variable coefficient Hirota equation, we discover numerous new
waveforms such as heart-shaped periodic wave solutions, O-shaped periodic wave
solutions etc. that have never been reported before, which are crucial in
theory and practice.Comment: arXiv admin note: text overlap with arXiv:2010.0941
Mesoscale modelling of concrete under high strain rate tension with a rate-dependent cohesive interface approach
This paper presents the investigation of the dynamic behaviour of concrete material under
high strain rate tension using an interface approach in a mesoscale model framework. A ratedependent cohesive constitutive description is introduced into the mesoscale framework to
account for the effects of viscosity occurring in the dynamic fracture process. An algorithm is
developed to insert cohesive elements throughout the mesoscale mesh grids in a concrete
specimen, and to identify the cohesive element properties based on the original mesoscale
structure. After parameter studies in terms of the cohesive element properties, the proposed
model is validated against representative experimental data. The model is then employed to
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investigate the dynamic tensile behaviour of concrete under high strain rates. The underlying
mechanisms of the dynamic tensile strength increase of concrete, including the influence of
viscous effect from rate-dependent material description, the inertial effect from cracking and
the material heterogeneity, are discussed and identified respectively. Results demonstrate that
the viscous effect should be incorporated into the cohesive constitutive law to account for the
Stefan effect at low and moderate strain rates and the micro-crack inertial effect only plays a
significant role at a relatively high strain rate. Material heterogeneity does influence the
strength enhancement under dynamic loading and the significance of this effect increases
with the strain rate
Research on the Integration of Huxiang Red Culture Into the Labor Education of College Students
Huxiang red culture and college students’ labor education have rich theoretical achievements and practical resources, and both of them have the characteristics of education and advancement. This paper briefly describes the spiritual connotation and educational function of Huxiang red culture, discusses the internal correlation between Huxiang red culture and labor spirit, analyzes the necessity of the integration of the two, extracts the key variables affecting the integration of the two through theoretical research and practical research, and finally proposes the integration path of Huxiang red culture into college students’ labor education from four aspects: curriculum ideology and politics, practical education base, campus culture and new media platform
Overexpression of long non-coding RNA NORAD promotes invasion and migration in malignant melanoma via regulating the MIR-205-EGLN2 pathway.
Growing evidence suggests that long non-coding RNAs NORAD and miR-205 play a significant role in regulating cancer progression and metastasis. In this study, high expression of NORAD was firstly observed in melanoma tissues and human malignant melanoma cell lines, our aim was to study the interaction of them in the process of invasion and migration of malignant melanoma cells. NORAD, miR-205, and EGLN2 mRNA level in MM cells was detected by qRT-PCR. In situ hybridization (ISH) was performed to detect NORAD expression in MM tissues specimens. Effects of NORAD and miR-205 on Prolyl hydroxylase 2 (EGLN2) expression was explored by western blot in MM cells line. Dual-luciferase reporter assay was performed to verify the interaction relationship between NORAD and miR-205, as well as, miR-205 and EGLN2. Transwell assay was conducted to explore the effects of NORAD and miR-205 in vitro. Xenografts in nude mice experiment were used to confirm the role of NORAD and miR-205 in vivo. In vitro, NORAD knockdown significantly inhibited migration and invasion of malignant melanoma cells and elevated the expression of miR-205, there was an interaction between miR-205 and NORAD in the RNA-induced silencing complex. Upregulation of miR-205 induced significant inhibition of migratory and invasive ability compared with the scrambled control. However, downregulating NORAD largely reversed this effect. Furthermore, the regulatory effects of miR-205 on EGLN2 levels and the induction of endoplasmic reticulum stress were reversed by NORAD. In vivo, deletion of miR-205 induced tumor growth in nude mice. NORAD may play critical roles in tumorigenesis and progression of malignant melanoma by regulating of the miR-205-EGLN2 pathway, and may serve as a new therapeutic target
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