206 research outputs found
Truncated Nuclear Norm Minimization for Image Restoration Based On Iterative Support Detection
Recovering a large matrix from limited measurements is a challenging task
arising in many real applications, such as image inpainting, compressive
sensing and medical imaging, and this kind of problems are mostly formulated as
low-rank matrix approximation problems. Due to the rank operator being
non-convex and discontinuous, most of the recent theoretical studies use the
nuclear norm as a convex relaxation and the low-rank matrix recovery problem is
solved through minimization of the nuclear norm regularized problem. However, a
major limitation of nuclear norm minimization is that all the singular values
are simultaneously minimized and the rank may not be well approximated
\cite{hu2012fast}. Correspondingly, in this paper, we propose a new multi-stage
algorithm, which makes use of the concept of Truncated Nuclear Norm
Regularization (TNNR) proposed in \citep{hu2012fast} and Iterative Support
Detection (ISD) proposed in \citep{wang2010sparse} to overcome the above
limitation. Besides matrix completion problems considered in
\citep{hu2012fast}, the proposed method can be also extended to the general
low-rank matrix recovery problems. Extensive experiments well validate the
superiority of our new algorithms over other state-of-the-art methods
The Impact of Ownership Reform in Chinese Industry, 1995-2001
During the 1980s, the restructuring of Chinese industry was driven principally by the entry of new enterprises into the enterprise system and by the restructuring of managerial incentives. In 1993, China’s leadership formally inaugurated the shareholding experiment. This paper examines the impact on eight performance measures of the conversion of both state- and collective-owned enterprises to shareholding enterprises. The analysis distinguishes between the direct effect of conversion and the induced effect, involving the attraction of non-state investment, which reduces the proportion of state assets and state control rights. We find evidence for SOEs that both conversion and a decline in the share of state-owned assets motivate rising productivity and R&D intensity. While rising proportions of non-state assets motive lower employment and rising wages, the initial conversion effect is associated with higher employment and lower wages. These latter impacts may result from agreements with workers as part of the conversion process. The SOE conversion process exhibits selection bias in which SOEs with high rates of capital productivity and profitability, high tax burdens, and comparatively low wages and smaller labor forces are more likely to be selected for conversion. No similar selection bias is evident in the collective sector.http://deepblue.lib.umich.edu/bitstream/2027.42/39927/3/wp542.pd
The Impact of Ownership Reform in Chinese Industry, 1995-2001
During the 1980s, the restructuring of Chinese industry was driven principally by the entry of new enterprises into the enterprise system and by the restructuring of managerial incentives. In 1993, China’s leadership formally inaugurated the shareholding experiment. This paper examines the impact on eight performance measures of the conversion of both state- and collective-owned enterprises to shareholding enterprises. The analysis distinguishes between the direct effect of conversion and the induced effect, involving the attraction of non-state investment, which reduces the proportion of state assets and state control rights. We find evidence for SOEs that both conversion and a decline in the share of state-owned assets motivate rising productivity and R&D intensity. While rising proportions of non-state assets motive lower employment and rising wages, the initial conversion effect is associated with higher employment and lower wages. These latter impacts may result from agreements with workers as part of the conversion process. The SOE conversion process exhibits selection bias in which SOEs with high rates of capital productivity and profitability, high tax burdens, and comparatively low wages and smaller labor forces are more likely to be selected for conversion. No similar selection bias is evident in the collective sector.
Estimates of combining ability and heterosis for growth traits in a full diallel cross of three strains of common carp, Cyprinus carpio L.
We attempted to determine the combining ability and heterosis of body weight by performing 3 × 3 complete diallel crosses derived by crossing three common carps (Cyprinus carpio var. jian, Cyprinus carpio haematopterus Temminck et Schlegel and Cyprinus carpio haematopterus). In total, 1650 fish were tagged when they were 1.5 months of age. After five months, Jian carp (♂) × Huanghe carp (♀) attained greater weight than pure and other hybrids. By crossing with Jian, Huanghe and Heilongjiang carps have improved body weight compared to their purebred. Significant principal components (PCs) were generated from growth performance data and their statistical loadings. The first principal component had the highest Eigen value of 2.81 and accounted for 70.31% of the variability in the data set. Two crosses, Jian carp (♂) × Huanghe carp (♀) and Huanghe carp (♂) × Jian carp (♀) showed high SCA with regard to body weight. Both Heilongjiang carp (♂) × Jian carp (♀) and Heilongjiang carp (♂) × Huanghe carp (♀) had higher heterosis compared to their purebreds. Significant positive phenotypic correlations were also observed between body weight and body length, thickness and height. The aforementioned results listed were identified as the foundation for common carp selective breeding programs.Keywords: Common carp, cross-breeding, heterosisAfrican Journal of Biotechnology Vol. 12(22), pp. 3514-352
Controlling a Quadrotor Carrying a Cable-Suspended Load to Pass Through a Window
In this paper, we design an optimal control system for a quadrotor to carry a cable-suspended load flying through a window. As the window is narrower than the length of the cable, it is very challenging to design a practical control system to pass through it. Our solution includes a system identification component, a trajectory generation component, and a trajectory tracking control component. The exact dynamic model that usually derived from the first principles is assumed to be unavailable. Instead, a model identification approach is adopted, which relies on a simple but effective low order equivalent system (LOES) to describe the core dynamical characteristics of the system. After being excited by some specifically designed manoeuvres, the unknown parameters in the LOES are obtained by using a frequency based least square estimation algorithm. Based on the estimated LOES, a numerical optimization algorithm is then utilized for aggressive trajectory generation when relevant constraints are given. The generated trajectory can lead to the quadrotor and load system passing through a narrow window with a cascade PD trajectory tracking controller. Finally, a practical flight test based on an Astec Hummingbird quadrotor is demonstrated and the result validates the proposed approach
A New Analytic Alignment Method for a SINS
Analytic alignment is a type of self-alignment for a Strapdown inertial navigation system (SINS) that is based solely on two non-collinear vectors, which are the gravity and rotational velocity vectors of the Earth at a stationary base on the ground. The attitude of the SINS with respect to the Earth can be obtained directly using the TRIAD algorithm given two vector measurements. For a traditional analytic coarse alignment, all six outputs from the inertial measurement unit (IMU) are used to compute the attitude. In this study, a novel analytic alignment method called selective alignment is presented. This method uses only three outputs of the IMU and a few properties from the remaining outputs such as the sign and the approximate value to calculate the attitude. Simulations and experimental results demonstrate the validity of this method, and the precision of yaw is improved using the selective alignment method compared to the traditional analytic coarse alignment method in the vehicle experiment. The selective alignment principle provides an accurate relationship between the outputs and the attitude of the SINS relative to the Earth for a stationary base, and it is an extension of the TRIAD algorithm. The selective alignment approach has potential uses in applications such as self-alignment, fault detection, and self-calibration
Cooperative Spin Amplification
Quantum amplification is recognized as a key resource for precision
measurements. However, most conventional paradigms employ an ensemble of
independent particles that usually limit the performance of quantum
amplification in gain, spectral linewidth, etc. Here we demonstrate a new
signal amplification using cooperative 129Xe nuclear spins embedded within a
feedback circuit, where the noble-gas spin coherence time is enhanced by at
least one order of magnitude. Using such a technique, magnetic field can be
substantially pre-enhanced by more than three orders and is in situ readout
with an embedded 87Rb magnetometer. We realize an ultrahigh magnetic
sensitivity of 4.0 fT/Hz that surpasses the photon-shot noise and even
below the spin-projection noise of the embedded atomic magnetometer, allowing
for exciting applications including searches for dark matter with sensitivity
well beyond supernova constraints. Our findings extend the physics of quantum
amplification to cooperative spin systems and can be generalized to a wide
variety of existing sensors, enabling a new class of cooperative quantum
sensors.Comment: 7 pages, 4 figure
Design and frequency analysis of continuous finite-time-convergent differentiator
In this paper, a continuous finite-time-convergent differentiator is
presented based on a strong Lyapunov function. The continuous differentiator
can reduce chattering phenomenon sufficiently than normal sliding mode
differentiator, and the outputs of signal tracking and derivative estimation
are all smooth. Frequency analysis is applied to compare the continuous
differentiator with sliding mode differentiator. The beauties of the continuous
finite-time-convergent differentiator include its simplicity, restraining
noises sufficiently, and avoiding the chattering phenomenon
Research on the Calibration Method of Micro Inertial Measurement Unit for Engineering Application
With rapid development of micro fabrication technology, the production level of micro inertial devices has increased, which promoted the performance improvement of Micro Inertial Measurement Unit (MIMU). Measurement precision of MIMU is one of the most significant indexes, especially for the application of the guided spinning projectiles. In order to improve the measurement precision of MIMU, this paper presents a novel calibration method. The calibration model is established and the derivation for parameters estimation has been introduced. By the multirate tests and multiposition tests, all the parameters in the calibration model can be well estimated. Verification experiment shows that the proposed method has the same compensation effect as the traditional method, but it can alleviate the computing burden for the system. Thus the proposed method will have a wide application prospect for the future engineering calibration
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