104 research outputs found

    A Simple Exact Penalty Function Method for Optimal Control Problem with Continuous Inequality Constraints

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    We consider an optimal control problem subject to the terminal state equality constraint and continuous inequality constraints on the control and the state. By using the control parametrization method used in conjunction with a time scaling transform, the constrained optimal control problem is approximated by an optimal parameter selection problem with the terminal state equality constraint and continuous inequality constraints on the control and the state. On this basis, a simple exact penalty function method is used to transform the constrained optimal parameter selection problem into a sequence of approximate unconstrained optimal control problems. It is shown that, if the penalty parameter is sufficiently large, the locally optimal solutions of these approximate unconstrained optimal control problems converge to the solution of the original optimal control problem. Finally, numerical simulations on two examples demonstrate the effectiveness of the proposed method

    PhysBench: A Benchmark Framework for rPPG with a New Dataset and Baseline

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    In recent years, due to the widespread use of internet videos, physiological remote sensing has gained more and more attention in the fields of affective computing and telemedicine. Recovering physiological signals from facial videos is a challenging task that involves a series of preprocessing, image algorithms, and post-processing to finally restore waveforms. We propose a complete and efficient end-to-end training and testing framework that provides fair comparisons for different algorithms through unified preprocessing and post-processing. In addition, we introduce a highly synchronized lossless format dataset along with a lightweight algorithm. The dataset contains over 32 hours (3.53M frames) of video from 58 subjects; by training on our collected dataset both our proposed algorithm as well as existing ones can achieve improvements

    Development of a Low Motion-Noise Humanoid Neck: Statics Analysis and Experimental Validation

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    Abstract-This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The feature of low motion noises allows our system to work like a real human head/neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. The objective of this investigation is to facilitate using head-worn communication devices for the person who wears the protective equipment/uniform that usually produces communication-noise when the head/neck moves. Our low motion-noise humanoid neck system is based on the spring structure, which can generate 1 Degree of Freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electrodriven parts are embedded in the head/neck structure. Instead, the motions are driven by seven cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis of the system has been processed completely. Experimental results validate the analysis, and clearly show that the head/neck system can greatly mimic the motions of human head with an A-weighted noise level of 30 dB or below

    Quantum mechanics in an evolving Hilbert space

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    Many basis sets for electronic structure calculations evolve with varying external parameters, such as moving atoms in dynamic simulations, giving rise to extra derivative terms in the dynamical equations. Here we revisit these derivatives in the context of differential geometry, thereby obtaining a more transparent formalization, and a geometrical perspective for better understanding the resulting equations. The effect of the evolution of the basis set within the spanned Hilbert space separates explicitly from the effect of the turning of the space itself when moving in parameter space, as the tangent space turns when moving in a curved space. New insights are obtained using familiar concepts in that context such as the Riemann curvature. The differential geometry is not strictly that for curved spaces as in general relativity, a more adequate mathematical framework being provided by fiber bundles. The language used here, however, will be restricted to tensors and basic quantum mechanics. The local gauge implied by a smoothly varying basis set readily connects with Berry's formalism for geometric phases. Generalized expressions for the Berry connection and curvature are obtained for a parameter-dependent occupied Hilbert space spanned by nonorthogonal Wannier functions. The formalism is applicable to basis sets made of atomic-like orbitals and also more adaptative moving basis functions (such as in methods using Wannier functions as intermediate or support bases), but should also apply to other situations in which nonorthogonal functions or related projectors should arise. The formalism is applied to the time-dependent quantum evolution of electrons for moving atoms. The geometric insights provided here allow us to propose new finite-difference time integrators, and also better understand those already proposed

    Prognostic value and immune infiltration analyses of cuproptosis-related genes in hepatocellular carcinoma

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    The role of cuproptosis, a newly discovered form of programmed cell death, remains poorly understood in hepatocellular carcinoma (HCC). This study was aimed at constructing a novel cuproptosis model for analyzing the clinical features, mutation characteristics and immune profile of HCC associated with cuproptosis-related genes (CRG), and to analyze the prognostic value of CRGs in HCC. We comprehensively evaluated HCC datasets containing clinicopathological information from The Cancer Genome Atlas and GEO, on the basis of 19 CRGs. The prognostic value of the cuproptosis-related risk score was established. Our results revealed two clusters associated with cuproptosis. Cluster B exhibited pronounced isolated innate immune cell infiltration and poor prognosis, and significant differences in prognosis and immune infiltration were observed between the groups with high and low cuproptosis risk. High copper mortality risk scores were associated with an elevated tumor mutational burden (TMB) and poor prognosis. Our findings suggest that evaluating copper-death subtypes provides insights into CRGs. Moreover, the copper mortality risk score model aids in characterizing prognosis and immune infiltration independently of the TMB

    Molecular Characteristics of Staphylococcus aureus From Food Samples and Food Poisoning Outbreaks in Shijiazhuang, China

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    As an opportunistic pathogen worldwide, Staphylococcus aureus can cause food poisoning and human infections. This study investigated the sequence typing, the penicillin (blaZ) and methicillin (mec) resistance profiles of S. aureus from food samples and food poisoning outbreaks in Shijiazhuang City, and the staphylococcal enterotoxin (SE) types of the S. aureus isolates from food poisoning. A total of 138 foodborne S. aureus isolates were distributed into 8 clonal complexes (CCs) and 12 singletons. CC1, CC5, CC8, CC15, CC97, CC59, CC398, CC88, and CC7 were the predominant CCs of foodborne S. aureus isolates. Moreover, CC59, CC15, and CC5 were the most prevalent CCs in food poisoning outbreaks. SEE was the most commonly detected SE in food poisoning isolates. One hundred thirty-three S. aureus isolates harbored the penicillin-resistant gene blaZ, and nine isolates carried the mec gene. The present study further explained the relationship between S. aureus and foods and food poisoning and indicated the potential risk of S. aureus infection

    Viral Diversity and Its Relationship With Environmental Factors at the Surface and Deep Sea of Prydz Bay, Antarctica

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    A viral metagenomic analysis of five surface and two bottom water (878 meters below surface, mbs, and 3,357 mbs) samples from Prydz Bay, was conducted during February–March 2015. The results demonstrated that most of the DNA viruses were dsDNA viruses (79.73–94.06%, except at PBI1, 37.51%). Of these, Caudovirales (Siphoviridae, Myoviridae, and Podoviridae) phages were most abundant in surface seawater (67.67–71.99%), while nucleocytoplasmic large DNA viruses (NCLDVs) (Phycodnaviridae, Mimiviridae, and Pandoraviridae accounted for >30% of dsDNA viruses) were most abundant in the bottom water (3,357 mbs). Of the ssDNA viruses, Microviridae was the dominant family in PBI2, PBI3, PBOs, and PBI4b (57.09–87.55%), while Inoviridae (58.16%) was the dominant family in PBI1. Cellulophaga phages (phi38:1 and phi10:1) and Flavobacterium phage 11b, infecting the possible host strains affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes, were abundant in surface water dsDNA viromes. The long contig (PBI2_1_C) from the viral metagenomes were most similar to the genome architectures of Cellulophaga phage phi10:1 and Flavobacterium phage 11b from the Arctic Ocean. Comparative analysis showed that the surface viral community of Prydz Bay could be clearly separated from other marine and freshwater environments. The deep sea viral community was similar to the deep sea viral metagenome at A Long-term Oligotrophic Habitat Assessment Station (ALOHA, at 22°45′N, 158°00′W). The multivariable analysis indicated that nutrients probably played an important role in shaping the local viral community structure. This study revealed the preliminary characteristics of the viral community in Prydz Bay, from both the surface and the deep sea. It provided evidence of the relationships between the virome and the environment in Prydz Bay and provided the first data from the deep sea viral community of the Southern Ocean

    Analyse und Klassifizierung von Transkriptionsdaten für die Detektion von möglichen Biomarkern bei Karzinomen

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    Cancer is one of the main causes of death in developed countries, and cancer treatment heavily depends on successful early detection and diagnosis. Tumor biomarkers are helpful for early diagnose. The goal of this discovery method is to identify genetic variations as well as changes in gene expression or activity that can be linked to a typical cancer state. First, several cancer gene signaling pathways were introduced and then combined. 27 candidate genes were selected, through the analysis of several data sets in the GEO database, a few expression difference matrices were established. Those candidate genes were tested in the matrices and found five genes PLA1A, MMP14, CCND1, BIRC5 and MYC that have the potential to be tumor biomarkers. Two of these genes have been further discussed, PLA1A is a potential biomarker for prostate cancer, and MMP14 can be considered as a biomarker for NSC lung cancer. Finally, the significance of this study and the potential value of the two genes are discussed, and the future research in this direction is a prospect

    The Effect of Vitamin D Supplementation on Blood Lipids in Patients with Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials

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    Purpose. Studies have found that vitamin D supplementation may improve blood lipids in patients with polycystic ovary syndrome, but the results are controversial, so this study will further analyze the effect of vitamin D supplementation on blood lipids in patients with polycystic ovary syndrome. Methods. PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases were searched up to May 2020, to identify randomized controlled trials of the effect of vitamin D supplementation on blood lipids in patients with polycystic ovary syndrome. The Cochrane risk of bias tool was applied to assess the risk of bias, and RevMan5.3 software was used for statistical analysis. Results. Ten studies were included in this study, including 543 subjects. The results of the meta-analysis showed that, compared with placebo, vitamin D supplementation can significantly reduce total cholesterol level (WMD = –11.32, 95% CI = [–14.51, –8.41], P<0.00001), low-density lipoprotein cholesterol level (WMD = –4.83, 95% CI = [–7.52, –2.14], P=0.0004), and triglyceride level (WMD = –8.23, 95% CI = [–13.08, –3.38], P=0.0009, but the effect on high-density lipoprotein cholesterol level is not statistically significant (WMD = –0.32, 95%CI = [–1.24, 0.60], P=0.50). Conclusion. Vitamin D supplementation can significantly reduce total cholesterol, low-density lipoprotein cholesterol, and triglycerides in patients with polycystic ovary syndrome. However, it has no significant effect on high-density lipoprotein cholesterol

    In-situ CT characterization of 2D woven SiCf/SiC composite loading under compression

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    SiC fiber-reinforced SiC matrix composites (SiCf/SiC) with 2D woven fabric as preform were tested under compression with in-situ X-ray computed tomography. The microstructure and damage evolution of the material under continuous loading levels were accurately revealed by image reconstruction of CT data. There were inhomogeneous pores in SiCf/SiC composite because of the un-uniform fiber distribution in the preform. The result also showed that 2D woven SiCf/SiC composite had obvious non-linear characteristics by its compressive load-displacement curve, and the damage modes included transverse matrix cracking, interlayer cracking, longitudinal matrix cracking, and fiber bundle fracture. Matrix cracking tended to occur near the pores or holes of the material, and the number of longitudinal cracks was relatively high compared to the number of transverse cracks
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