Sparse Approximation of 3D Meshes Using the Spectral Geometry of the Hamiltonian Operator

The discrete Laplace operator is ubiquitous in spectral shape analysis, since its eigenfunctions are provably optimal in representing smooth functions defined on the surface of the shape. Indeed, subspaces defined by its eigenfunctions have been utilized for shape compression, treating the coordinates as smooth functions defined on the given surface. However, surfaces of shapes in nature often contain geometric structures for which the general smoothness assumption may fail to hold. At the other end, some explicit mesh compression algorithms utilize the order by which vertices that represent the surface are traversed, a property which has been ignored in spectral approaches. Here, we incorporate the order of vertices into an operator that defines a novel spectral domain. We propose a method for representing 3D meshes using the spectral geometry of the Hamiltonian operator, integrated within a sparse approximation framework. We adapt the concept of a potential function from quantum physics and incorporate vertex ordering information into the potential, yielding a novel data-dependent operator. The potential function modifies the spectral geometry of the Laplacian to focus on regions with finer details of the given surface. By sparsely encoding the geometry of the shape using the proposed data-dependent basis, we improve compression performance compared to previous results that use the standard Laplacian basis and spectral graph wavelets.     

Image content adaptive color breakup index for field sequential color displays using a dominant visual saliency method

An index that can predict the perceptual visibility of color breakup for varying image content is valuable in field sequential color displays, whereas the current indices are usually for fixed patterns. To solve this problem, an image database containing 25 diverse reference images and 125 test cases with various color breakup visibility was first established. Next, visual experiments using a 240‐Hz liquid crystal display were performed to acquire the subjective color breakup scores of the test cases. A theorem based on visual saliency theory was proposed that the color breakup perception is mainly determined by the image regions with visual saliency values higher than a certain threshold, called the dominant visual saliency regions. A computational model based on this theorem was developed to obtain objective color breakup scores of the test cases from retinal images with and without color breakup. An analysis of the objective and subjective results revealed a Pearson linear correlation coefficient as high as 0.82, which matches the top‐level image quality assessment algorithms. Finally, the proposed color breakup index was used to benchmark against several mainstream field sequential color algorithms to determine their performances in color breakup suppression.     

NapWell: An EOG-based Sleep Assistant Exploring the Effects of Virtual Reality on Sleep Onset

Virtual Reality - We present NapWell, a Sleep Assistant using virtual reality (VR) to decrease sleep onset latency by providing a realistic imagery distraction prior to sleep onset. Our proposed...     

Biological Evaluation and X‐ray Co‐crystal Structures of Cyclohexylpyrrolidine Ligands for Trypanothione Reductase,an Enzyme from the Redox Metabolism of Trypanosoma

The tropical diseases human African trypanosomiasis, Chagas disease, and the various forms of leishmaniasis are caused by parasites of the family of trypanosomatids. These protozoa possess a unique redox metabolism based on trypanothione and trypanothione reductase (TR), making TR a promising drug target. We report the optimization of properties and potency of cyclohexylpyrrolidine inhibitors of TR by structure‐based design. The best inhibitors were freely soluble and showed competitive inhibition constants (K_i) against Trypanosoma (T.) brucei TR and T. cruzi TR and in vitro activities (half‐maximal inhibitory concentration, IC₅₀) against these parasites in the low micromolar range, with high selectivity against human glutathione reductase. X‐ray co‐crystal structures confirmed the binding of the ligands to the hydrophobic wall of the “mepacrine binding site” with the new, solubility‐providing vectors oriented toward the surface of the large active site.     

Fractal scaling of coated soot aggregates

Recent field observations have shown soot aggregates (SAs) to contain significant amounts of surface coatings of organic compounds which obfuscate their native fractal morphology and make them visually appear as “near-spherical.” Morphologies of these aggregates are currently parameterized using fractal dimension (D_f) values greater than the universal 1.8. This is done to account for the supposedly morphological restructuring of an aggregate to a more compact form upon condensation of organic materials. Using multiple-angle light scattering analysis, it has been experimentally shown that restructuring of SA morphology only takes place during the evaporation process, not condensation. Based on this seminal finding, here we formulate the correct parameterizations to describe the morphology of surface coated aggregates. We perform detailed three-dimensional morphological characterization of computer simulated coated aggregates that mimic atmospheric SAs and show that their D_f remains invariant at 1.8 with increasing coating mass by as much as 18 fold. We find coating to affect only the fractal prefactor k₀, an understudied parameter which controls the aggregate shape anisotropy and local packing fraction of monomers. Specifically, k₀ was observed to scale with the ratio of aggregate's total (coating + bare) mass M_total to bare mass M_bare as k₀ = 1.34*(M_total/M_bare)^0.56.

Copyright © 2017 American Association for Aerosol Research     

An effective sensor for tool wear monitoring in face milling: Acoustic emission

Acoustic Emission (AE) has been widely used for monitoring manufacturing processes particularly those involving metal cutting. Monitoring the condition of the cutting tool in the machining process is very important since tool condition will affect the part size, quality and an unexpected tool failure may damage the tool, work-piece and sometimes the machine tool itself. AE can be effectively used for tool condition monitoring applications because the emissions from process changes like tool wear, chip formation i.e. plastic deformation, etc. can be directly related to the mechanics of the process. Also AE can very effectively respond to changes like tool fracture, tool chipping, etc. when compared to cutting force and since the frequency range is much higher than that of machine vibrations and environmental noises, a relatively uncontaminated signal can be obtained. AE signal analysis was applied for sensing tool wear in face milling operations. Cutting tests were carried out on a vertical milling machine. Tests were carried out for a given cutting condition, using single insert, two inserts (adjacent and opposite) and three inserts in the cutter. AE signal parameters like ring down count and rms voltage were measured and were correlated with flank wear values (VB max). The results of this investigation indicate that AE can be effectively used for monitoring tool wear in face milling operations.     

等离子体活化水对青椒尖孢镰刀菌的抑制作用

本文旨在研究等离子体活化水（Plasma activated water,PAW）对青椒腐败菌-尖孢镰刀菌（Fusarium oxysporum）AF93247的抑制作用。着重研究了制备功率（0~1.18 kW）和制备时间（0~420 min）对PAW物理性质的影响;PAW制备时间（0~60 min）对AF93247菌丝生长和分生孢子萌发的影响,PAW处理时间（0~60 min）对染菌青椒腐败率和品质的影响。实验结果表明,制备功率越高,PAW的氧化还原电位、电导率和温度越高,pH值越低。同一制备功率（0.90 kW）时,随制备时间延长,PAW对AF93247的抑制作用增强。制备60 min的PAW（即PAW60）处理AF93247样品后,其菌丝生长抑制率和孢子萌发抑制率分别为（15.00±1.14）%和（54.44±5.03）%,显著高于其他各组（p<0.05）;PAW60处理后的孢子受损程度也高于其他各组。贮藏实验中,PAW60处理30 min组的染菌青椒色差?E降低率和硬度H降低率与对照组无显著性差异（p>0.05）,青椒腐败率、叶绿素a和总叶绿素损失率显著低于其他各组（p<0.05）。综上,PAW60对尖孢镰刀菌AF93247的有良好抑制作用,用其处理青椒30 min可在14 d内有效抑制青椒腐败的同时最大程度保持其品质。     

10 MW级深冷液化空气储能发电系统自动启动控制方法研究

以10 MW级深冷液化空气储能发电系统为研究对象,简要介绍了技术原理、系统构成、主要设备及工艺流程,并从自动控制视角,分别设计了储、释能阶段的启动方法。基于该自动启动方法,可完成储能阶段空气净化及压缩、空气液化、储热和蓄冷子系统的联合运行以及释能阶段储热、蓄冷和膨胀发电子系统的联合运行,实现了储能阶段自动达到额定出液量及释能阶段自动满足额定发电量的需求,提高了能量型机械储能系统对电网负荷变化的响应速度。