Local Measurement and Reconstruction for Noisy Graph Signals

The emerging field of signal processing on graph plays a more and more important role in processing signals and information related to networks. Existing works have shown that under certain conditions a smooth graph signal can be uniquely reconstructed from its decimation, i.e., data associated with a subset of vertices. However, in some potential applications (e.g., sensor networks with clustering structure), the obtained data may be a combination of signals associated with several vertices, rather than the decimation. In this paper, we propose a new concept of local measurement, which is a generalization of decimation. Using the local measurements, a local-set-based method named iterative local measurement reconstruction (ILMR) is proposed to reconstruct bandlimited graph signals. It is proved that ILMR can reconstruct the original signal perfectly under certain conditions. The performance of ILMR against noise is theoretically analyzed. The optimal choice of local weights and a greedy algorithm of local set partition are given in the sense of minimizing the expected reconstruction error. Compared with decimation, the proposed local measurement sampling and reconstruction scheme is more robust in noise existing scenarios.Comment: 24 pages, 6 figures, 2 tables, journal manuscrip

Moment Inequalities in the Context of Simulated and Predicted Variables

This paper explores the effects of simulated moments on the performance of inference methods based on moment inequalities. Commonly used confidence sets for parameters are level sets of criterion functions whose boundary points may depend on sample moments in an irregular manner. Due to this feature, simulation errors can affect the performance of inference in non-standard ways. In particular, a (first-order) bias due to the simulation errors may remain in the estimated boundary of the confidence set. We demonstrate, through Monte Carlo experiments, that simulation errors can significantly reduce the coverage probabilities of confidence sets in small samples. The size distortion is particularly severe when the number of inequality restrictions is large. These results highlight the danger of ignoring the sampling variations due to the simulation errors in moment inequality models. Similar issues arise when using predicted variables in moment inequalities models. We propose a method for properly correcting for these variations based on regularizing the intersection of moments in parameter space, and we show that our proposed method performs well theoretically and in practice

Occluded Person Re-identification

Person re-identification (re-id) suffers from a serious occlusion problem when applied to crowded public places. In this paper, we propose to retrieve a full-body person image by using a person image with occlusions. This differs significantly from the conventional person re-id problem where it is assumed that person images are detected without any occlusion. We thus call this new problem the occluded person re-identitification. To address this new problem, we propose a novel Attention Framework of Person Body (AFPB) based on deep learning, consisting of 1) an Occlusion Simulator (OS) which automatically generates artificial occlusions for full-body person images, and 2) multi-task losses that force the neural network not only to discriminate a person's identity but also to determine whether a sample is from the occluded data distribution or the full-body data distribution. Experiments on a new occluded person re-id dataset and three existing benchmarks modified to include full-body person images and occluded person images show the superiority of the proposed method.Comment: 6 pages, 7 figures, IEEE International Conference of Multimedia and Expo 201

Imaging unresolved object using vortex mode detection

Resolution is an imaging system\u27s ability to distinguish object detail. The resolution ability is ultimately limited by diffraction, which is hard to avoid because it comes from the wave nature of light. The Rayleigh criterion given by the finite width of the Airy disk, is the generally accepted criterion for the minimum resolvable detail. This criterion was hard to overcome until the study of Optical Vortex Coronagraph (OVC) system. This system can eliminate the component of light that creates Airy disk. The left light, which can pass through the OVC system, contains spatial information from the observed object even if it is an unresolved object as defined by the Rayleigh criterion. This thesis challenges the Rayleigh criterion using the OVC system. It is not hard to obtain the feature information of a object by detecting the light power that enters the system and the power that eventually passes through the system. A binary points source example in this thesis shows that, even if the source is unresolved under the Rayleigh criterion, its power transmission contains the information of angular extent of the two points sources. The power transmission of an ellipse object can differentiate tiny differences between its long radius and short radius

Photogalvanic Effect in Different 2D Materials

Spintronics is based on the control of electron spin properties. Spin-polarized currents and pure spin currents are vital to spintronics. As a method to generate current only by illumination without imposing the bias voltage, the Photogalvanic effect now is used to realize spin-polarized current or pure spin current. In order to continuously reduce the size, it is particularly important to build spintronic devices at low-dimensional scales. Because of their outstanding optical and electronic properties, 2 dimensional materials have received extensive concern and research these years. In this review, we review the photoresponse of different materials under different illuminations and the use of Photogalvanic effect to generate spin-polarized currents and even pure spin currents. The materials studied in this article include two-dimensional transition metal dichalcogenides, Zigzag silicon-carbide nanoribbons and graphene nanoribbons at the edges of armchairs. This review article provides possible directions for material selection for new spintronic devices

Embracing traditional Chinese culture through design

As a designer from China I am constantly focused on my passion for design of China, This interest comes from both my commitment to deep-rooted Chinese traditions, and my concern with regards to the gradual loss of traditional cultural values within contemporary society. As a product designer, I really like designing daily object, through exploring the relationship between consciousness and behavior. I consider this connection in order to make objects more meaningful to users. This project discusses the current situations of Chinese traditions and cultural values, and the challenges they face to survive in the contemporary world. My mission is to arouse the resonance to traditional cultural values with modern Chinese and inspire them to carry out those values in details of everyday life