127 research outputs found
[email protected]. Supported by the Computing Research Association’s Distributed Mentor
No full text1 The wallpaper group classification algorithm published in the paper “A Computational Model for Periodic Pattern Perception Based on Frieze and Wallpaper Groups ” (Y. Liu, R.T. Collins and Y. Tsin, IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 26
CUHK electronic theses & dissertations collection
No full textLiu, Xueting.Thesis Ph.D. Chinese University of Hong Kong 2014.Includes bibliographical references (leaves 108-120).Abstracts also in Chinese.Title from PDF title page (viewed on 30, November, 2016)
Segmentation of lungs from volumetric CT-scan images using prior knowledge (shape and texture)
No full textThis thesis presents a hierarchical segmentation scheme for The segmentation of lungs from volumetric CT images that concerns variational segmentation methods, namely geodesic active surfaces (GAS) and active surfaces without edges (ASWE), a volumetric similarity registration technique, statistical shape modelling using principal component analysis (PCA), and volumetric texture modelling. GAS and ASWE are 3-D extensions of their 2-D version, geodesic active contours (GAC) and active contours without edges (ACWE). The two models are generalized into a unified framework, referred to as integrated active contours (IAS). Numerical implementation methods are derived for 3-D and the experiments are conducted both in 2-D and 3-D on synthetic and CT images. Global and local properties of active contours/surfaces under different parameter settings are presented and several applications of these models are proposed based on experimental results.The similarity registration technique aims tom find an optimal match between shapes with respect to rotation, scale and translation parameters. In this registration method, PCA is initially employed to calculate the principal axes of shapes. These principal axes are used to obtain a coarse match between shapes to be registered. Then geometric moments are exploited to estimate the isotropic scale parameter. The rotation and translation parameters are estimated by phase correlation techniques which take advantage of the fast Fourier transform (FFT). Experimental results demonstrate that the proposed technique, compared with the standard iterative gradient descent method, is fast, robust in the presence of severe noise, and suitable in registering various types of topologically complex volumetric shapes.Shape decomposition using PCA is the current state of the art and is widely drawn on in building deformable shape templates. The major problem to be solved in the modelling is to find proper PCA shape parameters that best approximate a novel shape of the same class. A comparison of popular methods for parameter estimation in the literature is presented and a hybrid coarse-to-fine method based on previous works is proposed.The method achieves satisfactory accuracy over previous works and is validated by a database of lung shapes.A hierarchical shape-based segmentation method that incorporates GAS, ASWE, similarity registration, and statistical shape modelling is proposed to extract lungs from volumetric low-dose CT images. The method is extensively experimented with a large variety of images including synthetic images with noise and occlusions, low-dose CT images with artificial noise and synthetic tumors, and a low-dose CT database. The results indicate that the method is robust against noise and occlusions.Last but not least, a novel volumetric texture modelling technique based on isotropic Gaussian Markov random field (IGMRF) is developed and applied to low-dose CT images of lungs. Based on the proposed texture modelling, a hard classification approach is suggested to provide proper initializations for the shape-based segmentation method and enables the segmentation to achieve a higher degree of automation. The method is evaluated by low-dose CT images with synthetic tumors and the low-dose CT database. The experimental results suggest its suitability for offering proper initializations for shape-based segmentation
Asymmetrasca cisiana Dworakowska 1971, n. comb.
No full textAsymmetrasca cisiana (Dworakowska, 1971), n. comb. Empoasca cisiana Dworakowska, 1971: 509 Distribution. China (Guangdong: "Tsin-ien, 100 km W of Canton" [from original description]) Note. This species is known only from the male holotype, which was not available for study.Published as part of Liu, Yang, Fletcher, Murray J., Dietrich, Christopher H. & Zhang, Ya-Lin, 2014, New species and records of Asymmetrasca (Hemiptera: Cicadellidae: Typhlocybinae: Empoascini) from China and name changes in Empoasca (Matsumurasca), pp. 327-350 in Zootaxa 3768 (3) on page 329, DOI: 10.11646/zootaxa.3768.3.4, http://zenodo.org/record/22724
Trust, identity, and commercial advantage: Hainanese upward mobility in the rice trade on the east coast of peninsular Thailand (mid-19th century—1980s)
No full textThis thesis examines the rise and decline of the rice trade on the east coast of peninsular Thailand from the middle of the nineteenth century to the 1980s, in order to rectify the image of the Chinese middleman in Southeast Asia as the evil “blood suckers”; furthermore, to demonstrate the heterogeneity inside the Chinese community in Southeast Asia, and the hierarchical structure and mobility within a specific trade; in addition, to emphasize the significance of personal trust and credit relationships embedded in particular exchange relations, in the traditional markets characterized by contract uncertainty where the legal framework for the enforcement of contracts is not well developed
Parental differences in family processes in Chinese families experiencing economic disadvantage
No full textAuthor name used in this publication: Leung, Janet Tsin Yee.Author name used in this publication: Shek, Daniel Tan Lei.2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedC
Robust similarity registration technique for volumetric shapes represented by characteristic functions
No full textThis paper proposes a novel similarity registration technique for volumetric shapes implicitly represented by their characteristic functions (CFs). Here, the calculation of rotation parameters is considered as a spherical cross-correlation problem and the solution is therefore found using the standard phase correlation technique facilitated by principal components analysis (PCA).Thus, fast Fourier transform (FFT) is employed to vastly improve efficiency and robustness. Geometric moments are then used for shape scale estimation which is independent from rotation and translation parameters. It is numerically demonstrated that our registration method is able to handle shapes with various topologies and robust to noise and initial poses. Further validation of our method is performed by registering a lung database
Analyzing the health status of crowd workers compared to desk workers
No full textMicrotask crowdsourcing workers, also known as crowd workers, perform small tasks known as microtasks.These people use crowdsourcing platforms to complete these microtasks.Crowd workers have to work in front of a screen to complete these microtasks, risking musculoskeletal problems and other mental problems.Their working conditions look similar to desk workers, who are people that work remotely or at the office behind a desk.This study aims to find the health differences between crowd workers and desk workers.It will provide a general overview on the subjective well-being, experienced and mental health.In order to analyze the differences in health, a survey will be deployed on a crowdsourcing platform in order to recruit crowd workers and desk workers will be recruited through snowball sampling.The questions of the survey are divided into 5 groups, each representing a health category: general health, workspace quality, physical well-being, social well-being and emotional well-being.For this study 17 crowd workers were recruited and 9 desk workers.From the results, desk workers are healthier in general, have a healthier workspace because some desk workers work in ergonomically good offices, a healthier physical well-being, a healthier social well-being due to them having colleagues and a better emotional well-being. Crowd workers have a lower level of stress, because of the microtasks being mostly very simple, while desk workers have mentally demanding deadlines and projects to work on.CSE3000 Research ProjectComputer Science and Engineerin
HISTORIOGRAPHIC ASPECT OF FORMATION OF THE STATE BOUNDARY ON MATERIALS OF XIX – EARLY ХХ
No full textIn the article the author carries out the analysis of historiographic sources concerning the history of formation the Russian-Chinese boundary up to the beginning of the XX century. Author allocates several geographical areas, one of which (Urjanhajsky Territory) becomes a material for the description of specificity of boundaries formation between the Russian and the Tsin Empires. The author distinguishes two points of view on border demarcation and affiliation of Urjanchs’ territories. The author also describes the specificity of the borderline as the combination of a complex of matters concerning the boundary space.
Maladera panyuensis Ahrens, Fabrizi & Liu 2021, sp. n.
No full textMaladera panyuensis Ahrens, Fabrizi & Liu, sp. n. Figures 78 A–D, 130 Type material examined. Holotype: ♂ “[China] Canton, South China, Honam Island, Pan-yu District, 12.III.1948 ” (LSSYU). Paratypes: China: 1 ♂ “[China] Guilin, Guangxi, 19.III.1952 ” (IZAS), 1 ♂ “[China] Liangfeng, Guilin, Guangxi, 28.IV.1952 ” (IZAS), 1 ♂ “[China] Liangfeng, Guilin, Guangxi, 25.VI.1952 ” (IZAS), 1 ♂ “[China] Jingdong, Yunnan, 9.V.1957, 1200m, leg. Monschadski ” (IZAS), 1 ♂ “[China] Mts. Yanshan, Guilin, Guangxi, 17.V.1953 ” (IZAS), 1 ♂ “ Hainan, S. China, No-doa, Tan-hsien (District), 18-22.III.1935, 2200m, leg. F. K. To ” (LSSYU), 1 ♂ “[China] Mt. Yanshan, Guilin, Guangxi, 13.V. 1963, 200m, leg. Wang Chunguang ” (IZAS), 1 ♂ “Kiang-Si Chang-tsin-cheng” (ZMHB), 1 ♂ “ China 1942 Yun Hsien Apr. WL. Jellison” (USNM). Thailand: 1 ♂ “ Thailand bor. Hang Dong 6.1990. lgt. Wimmer” (ZFMK). Description. Length: 7.3 mm, length of elytra: 5.4 mm, width: 4.2 mm. Body oval, dark reddish brown, antenna brown, labroclypeus shiny, remainder of dorsal surface dull, except a few small setae on head and elytra glabrous. Labroclypeus subtrapezoidal, moderately wider than long, widest at base, lateral margins weakly convex and moderately convergent to moderately rounded anterior angles, lateral margin and ocular canthus producing a distinct blunt angle, margins strongly reflexed, anteriorly weakly emarginate medially; surface moderately convex medially, shiny, finely and densely punctate, distance between punctures less than their diameter, with few long, erect setae anteriorly; frontoclypeal suture slightly elevated and moderately bent medially; smooth area in front of eye approximately 3 times as wide as long; ocular canthus short and wide, finely densely punctate, with one terminal seta. Frons dull, with fine, dense punctures, glabrous except for a few setae beside eyes. Eyes large, ratio of diameter/interocular width: 0.7. Antenna with 10 antennomeres; club with three antennomeres, 1.2 times as long as remaining antennomeres combined. Mentum anteriorly elevated and flattened. Pronotum subtrapezoidal, widest at base, lateral margins convex and strongly convergent anteriorly, anterior angles produced and moderately sharp, anterior margin convex, marginal line complete; surface finely and densely punctate, with very minute setae in the punctures only; anterior and lateral margins setose. Scutellum wide, triangular, with fine and dense punctures each bearing a minute seta. Elytra oblong, widest at middle, striae well impressed, finely and densely punctate, intervals convex, with fine, dense punctures concentrated along striae, odd intervals with a few fine, erect, short setae, otherwise punctures with very minute setae; epipleural margin robust, ending at the strongly rounded external apical angle of elytra, epipleura densely setose, apical border membraneous, with a rim of short microtrichomes. Ventral surface dull, metasternum and metacoxa with large and dense punctures, sparsely setose on metasternal disc: metacoxa glabrous except for a several long setae laterally; each abdominal sternite in addition to generally distributed fine and moderately dense punctures with a distinct transverse row of coarse punctures each bearing a short and robust seta, punctures with microscopic setae, penultimate sternite apically with a very narrow shiny chitinous border. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.47. Pygidium large but moderately convex, finely and moderately densely punctate, with smooth impunctate midline, punctures with microscopic setae, with a few long setae along apical margin. Legs moderately wide and long; femora with two longitudinal rows of setae, finely and moderately densely punctate; metafemur dull, anterior margin acute, lacking an adjacent serrated line, posterior ventral margin medially straight, weakly widened in apical half and not serrate, dorsally not serrated, finely setose. Metatibia moderately wide and long, widest at apex, ratio width/length: 1/2.56, dorsally sharply carinate, with two groups of spines, basal one shortly before middle, apical one at two thirds of metatibial length, with a non-contiguous serrated line from base to the basal group of spines, beside it with a few punctures but without spines; lateral face longitudinally convex, shiny, with sparse and fine punctures on basal half, with minute setae in punctures; ventral margin serrate, with five equidistant spines; medial face not punctate, apex interiorly near tarsal articulation shallowly concave. Tarsomeres impunctate dorsally, ventrally with sparse, short setae; metatarsomeres ventrally with a strongly serrated ridge, subventral longitudinal carina absent; first metatarsomere slightly longer than following two tarsomeres combined and distinctly longer than dorsal tibial spur. Protibia moderately long, bidentate, claws of anterior tarsomeres symmetrical, feebly curved and long, with normally developed basal tooth. Aedeagus: Fig. 78 A–C. Habitus: Fig. 78D. Female unknown. Diagnosis. Maladera panyuensis Ahrens, Fabrizi & Liu, sp. n. resembles M. obscurata (Moser) in external appearance, but it is more elongate and larger. The new species can be distinguished further in having large basal lobes on the parameres. Etymology. The new species is named after the type locality, Panyu (adjective in the nominative singular). Variation. Length: 6.6–7.6 mm, length of elytra: 5.2–5.9 mm, width: 4.3–4.5 mm. Distribution. See map (Fig. 130) and Table 1.Published as part of Fabrizi, Silvia, Liu, Wan-Gang, Bai, Ming, Yang, Xing-Ke & Ahrens, Dirk, 2021, A monograph of the genus Maladera Mulsant & Rey, 1871 of China (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), pp. 1-400 in Zootaxa 4922 (1) on pages 327-328, DOI: 10.11646/zootaxa.4922.1.1, http://zenodo.org/record/449631
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