918 research outputs found
Kong jian pin lu zai Zhong Ying wen ju zi yue du zhong de zuo yong
No full textHan, Qiming.Thesis M.Phil. Chinese University of Hong Kong 2014.Includes bibliographical references (leaves 63-65).Abstracts also in Chinese.Title from PDF title page (viewed on 03, October, 2016).Han, Qiming
Miniaturized wide-angle rasorber with a wide inter-absorption high transparent bandpass based on multiple 2.5-D resonators
No full textA miniaturized high selectivity Frequency Selective Rasorber (FSR) with a wide inter-absorption high transparent bandpass based on multiple 2.5-Dimensional (2.5-D) resonators is investigated. The main contribution is the achievement of a wide and high transparent passband by combining the large inductance of Parallel Resonators (PRs) and cascading two 2.5-D PRs, which also provide the function of miniaturization. The 2.5- D PR is implemented by connecting the interdigited capacitor and the metal meandered strip-line on both surfaces of a lossy layer through metalized vias. The inductor and capacitor values of 2.5-D PR can be individually adjusted to shift passband’s central frequency. The lossy element is realized by inserting two 2.5-D strip-type PRs at the center of each side of a meandered cross-dipole loaded with two resistive sheets on both sides. An Equivalent Circuit Model (ECM) is proposed to analyze its operating principle. The dimensions of the miniaturized element are 0.12λL×0.12λL×0.118λL. While maintaining good wide passband (-1dB relative bandwidth is 21.2%), the miniaturized FSR satisfies the characteristic of polarization insensitivity (TE and TM) and angular insensitivity (up to 45°). A prototype of miniaturized FSR has been manufactured and measured, showing a reasonable agreement with simulations
Revisit the open nature of open vocabulary semantic segmentation
No full textIn Open Vocabulary Semantic Segmentation (OVS), we observe a consistent drop in model performance as the query vocabulary set expands, especially when it includes semantically similar and ambiguous vocabularies, such as ‘sofa’ and ‘couch’. The previous OVS evaluation protocol, however, does not account for such ambiguity, as any mismatch between model-predicted and human-annotated pairs is simply treated as incorrect on a pixel-wise basis. This contradicts the open nature of OVS, where ambiguous categories may both be correct from an open- world perspective. To address this, in this work, we study the open nature of OVS and propose a mask-wise evaluation protocol that is based on matched and mis- matched mask pairs between prediction and annotation respectively. Extensive experimental evaluations show that the proposed mask-wise protocol provides a more effective and reliable evaluation framework for OVS models compared to the previous pixel-wise approach on the perspective of open-world. Moreover, analy- sis of mismatched mask pairs reveals that a large amount of ambiguous categories exist in commonly used OVS datasets. Interestingly, we find that reducing these ambiguities during both training and inference enhances capabilities of OVS mod- els. These findings and the new evaluation protocol encourage further exploration of the open nature of OVS, as well as broader open-world challenges. Project page: https://qiming-huang.github.io/RevisitOVS/.<br/
Analysis of acoustic damping in duct terminated by porous absorption materials based on analytical models and finite element simulations
No full textAcoustic absorption materials are widely used today to dampen and attenuate the noises which exist almost everywhere and have adverse impact upon daily life of human beings. In order to evaluate the absorption performance of such materials, it is necessary to experimentally determine acoustic properties of absorption materials. Two experimental methods, one is Standing Wave Ratio Method and the other is Transfer-Function Method, which also totally called as Impedance Tube Method, are based on two analytical models people have used to evaluate and validate the data obtained from acoustic impedance analyzers. This thesis first reviews the existing analytical models of previous two experimental methods in the literature by looking at their analytical models, respectively. Then a new analytical model is developed is developed based on One-Microphone Method and Three-Microphone Method, which are two novel experimental approaches. Comparisons are made among these analytical models, and their advantages and disadvantages are discussed.M.S.Includes bibliographical referencesby Qiming Gua
Revisit the open nature of open vocabulary semantic segmentation
No full textIn Open Vocabulary Semantic Segmentation (OVS), we observe a consistent drop in model performance as the query vocabulary set expands, especially when it includes semantically similar and ambiguous vocabularies, such as ‘sofa’ and ‘couch’. The previous OVS evaluation protocol, however, does not account for such ambiguity, as any mismatch between model-predicted and human-annotated pairs is simply treated as incorrect on a pixel-wise basis. This contradicts the open nature of OVS, where ambiguous categories may both be correct from an open- world perspective. To address this, in this work, we study the open nature of OVS and propose a mask-wise evaluation protocol that is based on matched and mis- matched mask pairs between prediction and annotation respectively. Extensive experimental evaluations show that the proposed mask-wise protocol provides a more effective and reliable evaluation framework for OVS models compared to the previous pixel-wise approach on the perspective of open-world. Moreover, analy- sis of mismatched mask pairs reveals that a large amount of ambiguous categories exist in commonly used OVS datasets. Interestingly, we find that reducing these ambiguities during both training and inference enhances capabilities of OVS mod- els. These findings and the new evaluation protocol encourage further exploration of the open nature of OVS, as well as broader open-world challenges. Project page: https://qiming-huang.github.io/RevisitOVS/.<br/
Revisit the open nature of open vocabulary semantic segmentation
No full textIn Open Vocabulary Semantic Segmentation (OVS), we observe a consistent drop in model performance as the query vocabulary set expands, especially when it includes semantically similar and ambiguous vocabularies, such as ‘sofa’ and ‘couch’. The previous OVS evaluation protocol, however, does not account for such ambiguity, as any mismatch between model-predicted and human-annotated pairs is simply treated as incorrect on a pixel-wise basis. This contradicts the open nature of OVS, where ambiguous categories may both be correct from an open- world perspective. To address this, in this work, we study the open nature of OVS and propose a mask-wise evaluation protocol that is based on matched and mis- matched mask pairs between prediction and annotation respectively. Extensive experimental evaluations show that the proposed mask-wise protocol provides a more effective and reliable evaluation framework for OVS models compared to the previous pixel-wise approach on the perspective of open-world. Moreover, analy- sis of mismatched mask pairs reveals that a large amount of ambiguous categories exist in commonly used OVS datasets. Interestingly, we find that reducing these ambiguities during both training and inference enhances capabilities of OVS mod- els. These findings and the new evaluation protocol encourage further exploration of the open nature of OVS, as well as broader open-world challenges. Project page: https://qiming-huang.github.io/RevisitOVS/.<br/
Comentário a “A study of the styles and characteristics of basic music theory textbooks in China in the past 100 years”
No full textComment on “A study of the styles and characteristics of basic music theory textbooks in China in the past 100 years”Commented Article: YU, Feng; ZHANG, Qiming; THUY, Pham Minh. A study of the styles and characteristics of basic music theory textbooks in China in the past 100 years. Trans/Form/Ação: Unesp journal of philosophy, v. 46, Special Issue, p. 117- 144, 2023
Photocatalytic degradation of 2,4,6-trichlorophenol over g-C3N4 under visible light irradiation.pdf
No full textThe presence of pharmaceuticals in aquatic environment has become a topic of concern because of their potential adverse effects on human health and wildlife species. A total of 45 dewatered sewage sludge samples were collected throughout China and analyzed for 30 commonly consumed pharmaceutical residues. Ofloxacin was found to be the dominant contaminant with concentrations up to 24760 mu g kg(-1), followed by oxytetracycline (52801 mu g kg(-1)), norfloxacin (5280 mu g kg(-1)) and ketoprofen (4458 mu g kg(-1)). The concentration of pharmaceutical residues varied greatly depending on the operation conditions of wastewater treatment plants and sampling locations. Poor agreement was found between the predicted (calculation based on the annual consumption and coefficient of sludge water partition) and detected concentrations of the pharmaceuticals indicating that the occurrence of pharmaceutical residues was affected by various factors such as loading rates, sewage properties and the chemical properties such as the contribution from polar groups. National wide fate and ecotoxicity study is required for the development of control strategies. (C) 2013 Elsevier Ltd. All rights reserved.The presence of pharmaceuticals in aquatic environment has become a topic of concern because of their potential adverse effects on human health and wildlife species. A total of 45 dewatered sewage sludge samples were collected throughout China and analyzed for 30 commonly consumed pharmaceutical residues. Ofloxacin was found to be the dominant contaminant with concentrations up to 24760 mu g kg(-1), followed by oxytetracycline (52801 mu g kg(-1)), norfloxacin (5280 mu g kg(-1)) and ketoprofen (4458 mu g kg(-1)). The concentration of pharmaceutical residues varied greatly depending on the operation conditions of wastewater treatment plants and sampling locations. Poor agreement was found between the predicted (calculation based on the annual consumption and coefficient of sludge water partition) and detected concentrations of the pharmaceuticals indicating that the occurrence of pharmaceutical residues was affected by various factors such as loading rates, sewage properties and the chemical properties such as the contribution from polar groups. National wide fate and ecotoxicity study is required for the development of control strategies. (C) 2013 Elsevier Ltd. All rights reserved
Halide Removal from Water by Novel Bismuth Materials
No full textWater is scarce and there is a high demand for water usage at different parts of domestic usage (9%), agriculture (70%) and industries (21%). The halides in natural and sea waters are typically of a ration of Cl: Br: I is 100-200:10:1, which means chloride is 10-20 times more than bromide and bromide is 10 times of iodide. Excessive halides-release into the water could be as a result of natural or human activities, for example, mining and produced waters from oil and gas industries could release a high level of halides in water. Removal of excessive amount of halides is crucial for human and living creatures. High chloride concentration could lead to destruction to aquatic lives (as indicated by A. maculatum and R. sylvatica), phytotoxicity, crop damage, corrosion of pipes, and other infrastructures (such as reduced electrode lifetime in hydrometallurgy). Iodide/iodine has some radioactive isotopes and contributed to the environmental disasters during the Chernobyl and Fukushima catastrophes. However, iodide and bromide even at very low concentrations also could bring up problems in health issues such as producing disinfection by-products (DBPs) during water treatment.
More than 600 species of DBPs could be produced in the chlorination disinfections process, and some of the DBPs are known to be very toxic and their levels in water are so restricted. For example, Environmental Protection Agency (EPA) has set limitations for chloroform and bromodichloromethane at 80 and 60 ppb, respectively. The best way to avoid DBPs production is to remove the excessive amount of halides before application of any kind of oxidation for water treatment.
This thesis is focused on removal of Cl-, Br- and I- ions in water. F- is excluded because F- is much easier to precipitate out in comparison to the other three halide anions. Two types of novel bismuth-based materials have been developed for removal of halides at high concentrations (> 1000 mg/L) and low concentrations (< 10 mg/L), respectively. The high concentration halide removal addresses issues in mining industry, whilst the low concentration removal addresses the issue of drinking water quality.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Eng & Built EnvScience, Environment, Engineering and TechnologyFull Tex
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