Exact Asymptotic Behavior of Singular Positive Solutions of Fractional Semi-Linear Elliptic Equations

In this paper, we prove the exact asymptotic behavior of singular positive solutions of fractional semi-linear equations $$(-\Delta)^\sigma u = u^p~~~~~~~~in ~~ B_1\backslash \{0\}$$ with an isolated singularity, where $\sigma \in (0, 1)$ and $\frac{n}{n-2\sigma} < p < \frac{n+2\sigma}{n-2\sigma}$.Comment: 11 page

Qualitative analysis for an elliptic system in the punctured space

In this paper, we investigate the qualitative properties of positive solutions for the following two-coupled elliptic system in the punctured space: $$\begin{cases} -\Delta u =\mu_1 u^{2q+1} + \beta u^q v^{q+1} \\ -\Delta v =\mu_2 v^{2q+1} + \beta v^q u^{q+1} \end{cases} \textmd{in} ~\mathbb{R}^n \backslash \{0\},$$ where $\mu_1, \mu_2$ and $\beta$ are all positive constants, $n\geq 3$. We establish a monotonicity formula that completely characterizes the singularity of positive solutions. We prove a sharp global estimate for both components of positive solutions. We also prove the nonexistence of positive semi-singular solutions, which means that one component is bounded near the singularity and the other component is unbounded near the singularity.Comment: 27 page

Effective Superpotentials of Type II D-brane/F-theory on Compact Complete Intersection Calabi-Yau Threefolds

In this paper, we extend the GKZ-system method to the more general case: compact Complete Intersection Calabi-Yau manifolds (CICY). For several one-deformation modulus compact CICYs with D-branes, the on-shell superpotentials in this paper from the extended GKZ-system method are exactly consistent with published results obtained from other methods. We further compute the off-shell superpotentials of these models. Then we obtain both the on-shell and off-shell superpotentials for sev- eral two-deformation moduli compact CICYs with D-branes by using the extended GKZ-system method. The discrete symmetrical groups, Z2, Z3 and Z4, of the holo- morphic curves wrapped by D-branes play the important roles in computing the superpotentials, in some sense, they are the quantum symmetries of these models. Furthermore, through the mirror symmetry, the Ooguri-Vafa invariants are extracted from the A-model instanton expansion

Flexible Expectile Regression in Reproducing Kernel Hilbert Space

Expectile, first introduced by Newey and Powell (1987) in the econometrics literature, has recently become increasingly popular in risk management and capital allocation for financial institutions due to its desirable properties such as coherence and elicitability. The current standard tool for expectile regression analysis is the multiple linear expectile regression proposed by Newey and Powell in 1987. The growing applications of expectile regression motivate us to develop a much more flexible nonparametric multiple expectile regression in a reproducing kernel Hilbert space. The resulting estimator is called KERE which has multiple advantages over the classical multiple linear expectile regression by incorporating non-linearity, non-additivity and complex interactions in the final estimator. The kernel learning theory of KERE is established. We develop an efficient algorithm inspired by majorization-minimization principle for solving the entire solution path of KERE. It is shown that the algorithm converges at least at a linear rate. Extensive simulations are conducted to show the very competitive finite sample performance of KERE. We further demonstrate the application of KERE by using personal computer price data

Chiral Symmetry Breaking in Micro-Ring Optical Cavity By Engineered Dissipation

We propose a method to break the chiral symmetry of light in traveling wave resonators by coupling the optical modes to a lossy channel. Through the engineered dissipation, an indirect dissipative coupling between two oppositely propagating modes can be realized. Combining with reactive coupling, it can break the chiral symmetry of the resonator, allowing light propagating only in one direction. The chiral symmetry breaking is numerically verified by the simulation of an electromagnetic field in a micro-ring cavity, with proper refractive index distributions. This work provokes us to emphasize the dissipation engineering in photonics, and the generalized idea can also be applied to other systems.Comment: 6 pages, 3 figure

Sliced Wasserstein Kernels for Probability Distributions

Optimal transport distances, otherwise known as Wasserstein distances, have recently drawn ample attention in computer vision and machine learning as a powerful discrepancy measure for probability distributions. The recent developments on alternative formulations of the optimal transport have allowed for faster solutions to the problem and has revamped its practical applications in machine learning. In this paper, we exploit the widely used kernel methods and provide a family of provably positive definite kernels based on the Sliced Wasserstein distance and demonstrate the benefits of these kernels in a variety of learning tasks. Our work provides a new perspective on the application of optimal transport flavored distances through kernel methods in machine learning tasks

Edge Detection Methods Based on Differential Phase Congruency of Monogenic Image

Edge Detection Methods Based on Differential Phase Congruency of Monogenic Image Abstract: Edge detection has been widely used in medical image processing and automatic diagnosis. Some novel edge detection algorithms,based on the monogenic scale-space, are proposed by detecting points of local extrema in local amplitude, the local attenuation and modified differential phase congruency methods. The monogenic scale-space is obtained from a known image by Poisson and conjugate Poisson filtering. In mathematics, it is the Hardy space in the upper half-space. The boundary value of the monogenic scale-space representation is a monogenic image. In the monogenic scale-space, the definitions involving scale, such as local amplitude,local attenuation, local phase angle, local phase vector and local frequency (phase derivatives) are proposed. Using Clifford analysis, the relations between the local attenuation and the local phase vector are obtained. These study will be improved the understanding of image analysis in higher dimensional spaces. Experimental results are shown by using some typical images.Comment: 18 pages, 2 figure

Security of Medical Cyber-physical Systems: An Empirical Study on Imaging Devices

Recent years have witnessed a boom of connected medical devices, which brings security issues in the meantime. Medical imaging devices, an essential part of medical cyber-physical systems, play a vital role in modern hospitals and are often life-critical. However, security and privacy issues in these medical cyber-physical systems are sometimes ignored. In this paper, we perform an empirical study on imaging devices to analyse the security of medical cyber-physical systems. To be precise, we design a threat model and propose prospective attack techniques for medical imaging devices. To tackle potential cyber threats, we introduce protection mechanisms, evaluate the effectiveness and efficiency of protection mechanisms as well as its interplay with attack techniques. To scoring security, we design a hierarchical system that provides actionable suggestions for imaging devices in different scenarios. We investigate 15 devices from 9 manufacturers to demonstrate empirical comprehension and real-world security issues

Fast and Accurate Graph Stream Summarization

A graph stream is a continuous sequence of data items, in which each item indicates an edge, including its two endpoints and edge weight. It forms a dynamic graph that changes with every item in the stream. Graph streams play important roles in cyber security, social networks, cloud troubleshooting systems and other fields. Due to the vast volume and high update speed of graph streams, traditional data structures for graph storage such as the adjacency matrix and the adjacency list are no longer sufficient. However, prior art of graph stream summarization, like CM sketches, gSketches, TCM and gMatrix, either supports limited kinds of queries or suffers from poor accuracy of query results. In this paper, we propose a novel Graph Stream Sketch (GSS for short) to summarize the graph streams, which has the linear space cost (O(|E|), E is the edge set of the graph) and the constant update time complexity (O(1)) and supports all kinds of queries over graph streams with the controllable errors. Both theoretical analysis and experiment results confirm the superiority of our solution with regard to the time/space complexity and query results' precision compared with the state-of-the-art

Interference control of nonlinear excitation in a multiatom cavity QED system

We show that by manipulating quantum interference in a multi-atom cavity QED system, the nonlinear excitation of the cavity-atom polariton can be resonantly enhanced while the linear excitation is suppressed. Under appropriate conditions, it is possible to selectively enhance or suppress the polariton excitation with two free-pace laser fields. We report an experiment with cold Rb atoms in an optical cavity and present experimental results that demonstrate such interference control of the cavity QED excitation and its direct applications for studies of all-optical switching and cross-phase modulation of the cavity transmitted light.Comment: 4 pages, 5 figure