Frustum PointNets for 3D Object Detection from RGB-D Data

In this work, we study 3D object detection from RGB-D data in both indoor and outdoor scenes. While previous methods focus on images or 3D voxels, often obscuring natural 3D patterns and invariances of 3D data, we directly operate on raw point clouds by popping up RGB-D scans. However, a key challenge of this approach is how to efficiently localize objects in point clouds of large-scale scenes (region proposal). Instead of solely relying on 3D proposals, our method leverages both mature 2D object detectors and advanced 3D deep learning for object localization, achieving efficiency as well as high recall for even small objects. Benefited from learning directly in raw point clouds, our method is also able to precisely estimate 3D bounding boxes even under strong occlusion or with very sparse points. Evaluated on KITTI and SUN RGB-D 3D detection benchmarks, our method outperforms the state of the art by remarkable margins while having real-time capability.Comment: 15 pages, 12 figures, 14 table

The development of an automated system for electrical characterization of cells using a novel force balance method

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 86-90).Dielectrophoresis (DEP), a cell separation technique based on the dielectric properties, has significantly advanced biomedical research in diverse applications ranging from blood stem cells purification to cancer cells isolation from heterogeneous populations. The ability to accurately measure the dielectric properties of individual cells is not only critical for effective sorting applications, but is also advantageous for enhancing the current knowledge of cell biology. This thesis proposes a novel method: the n-DEP spring, which applies an electrical field gradient upon continuously flowing cells to distinguish them based on their individual DEP properties. Specifically, the method uses the equilibrium position originating from the force balance between hydrodynamic and DEP forces to infer the cellular dielectric properties. For thorough DEP characterization, changing different conditions of cells is an essential but time-consuming process which usually takes hours to days. Especially for DEP characterization of time-sensitive events, such as neutrophil activation or cell apoptosis, short characterization time is required. This thesis describes the automation of the fluidic, optics, and electronics components of the DEP characterization system, which shortens the characterization time within an hour. We first demonstrated the automated DEP characterization of a mammalian cell type in thirty-nine conditions within an hour. Subsequently, we characterized the neutrophils with different activation states and successfully found out the right conditions to discriminate the activated neutrophils and non-activated neutrophils. With this system and method, we now have the potential to rapidly screen through a variety of system parameters, and optimize conditions for effective cell sorting.by Hao-Wei Su.S.M

A review of millimeter-wave radar research

With the rapid development of scientifi c research and the maturity of technology, millimeter-wave radar has become the focus of research in industrial production, national defense construction and other fi elds because of its high precision and high applicability. This paper introduces the application fields and algorithm development of millimeter wave radar, expounds the common application scenarios of millimeter wave radar, and gradually elaborates the development and update of radar detection algorithm, on this basis, the new research direction of millimeter wave radar and the improved algorithm idea of FMCW millimeter wave radar detection algorithm are proposed

Does political conflict affect bilateral trade or vice versa? Evidence from Sino-U.S. relations

This paper investigates the dynamic causal relationship between Sino-U.S. political conflict and bilateral trade using a time-varying (bootstrap) Granger full-sample causality test and sub-sample rolling window estimation. The result indicates that Sino-U.S. political conflict and bilateral trade may interact in various ways. Bilateral trade has both positive and negative effects on political conflict in several sub-phases, and in turn, political conflict has the same impacts on bilateral trade. In general, the relationship between Sino-U.S. political conflict and bilateral trade is not always consistent with the model of Polachek, which states bilateral trade has significantly reduced political conflict. In the face of a severe economic situation, China and the U.S. government should strengthen trade cooperation and seek common ground of economic interests in order to expand the improvement of political relations

Should gold be stored in chaotic eras?

This article explores the necessity to store gold in chaotic eras from the perspective of geopolitical risk (G.P.R.). We examine the casual relationship between G.P.R. and gold price (G.P.) by applying the full- and sub-sample rolling-window bootstrap causality test. The positive effect from G.P.R. to G.P. reveals that gold should be stored in chaotic eras, due to its rising price during high risks of geopolitics. However, the negative effect does not confirm this view, G.P. may decrease during certain high G.P.R. periods, which are not necessary to store gold. G.P. may also increase during periods of low G.P.R., in order to hedge risks of economic crises, rather than geopolitical events. These results are inconsistent with the capital asset pricing model, which highlights a positive effect from G.P.R. to G.P. In turn, the positive influence of G.P. on G.P.R. points out that the gold market can be an effective predictor of the risks of geopolitics. In the context of an unstable pattern of global politics, investors and governments can benefit from the gold value in the chaotic eras to avoid losses and optimize investment. In turn, they can accurately predict G.P.R. based on G.P., in order to prevent G.P.R.s

Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping

Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells’ interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size.Swedish Research Council (Grant 2012-6708)Royal Physiographic SocietyHertz Foundatio

Giant vortex in a fast rotating holographic superfluid

In a holographic superfluid disk, when the rotational velocity is large enough, we find a giant vortex will form in the center of the system by merging several single charge vortices at some specific rotational velocity, with a phase stratification phenomenon for the order parameter. The formation of a giant vortex can be explained as there is not enough space for a standard vortex lattice. Keep increasing the rotational velocity the giant vortex will disappear and there will be an appearance of a superfluid ring. In the giant vortex region, the number of vortices measured from winding number and rotational velocity always satisfies the linear Feynman relation. However, when the superfluid ring starts to appear, the number of vortices in the disk will decrease though the rotational velocity is increasing, where most of the order parameter is suppressed