54,870 research outputs found
Flow dynamics on a U shaped channel flow: a numerical study
No full textThe paper deals with the numerical simulation of river channel flows at laboratory scale. The adopted geometry
consists of a U shaped trapezoidal smooth open channel with fixed slope. The branches, 3m of length each, are linked with a joint, 0.40m long, realizing two 90 degrees bends. The system is fed upstream with a water discharge under critical conditions while a Cipolletti weir is set downstream to control flow profiles.
Steady flow movements are obtained by means of two different softwares: a pure Lagrangian developed by the author, based on the Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) technique and Flow3D®, a commercial CFD software based on a Finite Volume formulation of the Navier Stokes equations in the Eulerian framework. Depending on the assumed boundary conditions, velocity profiles and water interfaces at certain cross sections are deducted by using the codes. Results are discussed and compared, showing a satisfactory agreement
GaitASMS: gait recognition by adaptive structured spatial representation and multi-scale temporal aggregation
No full textGait recognition is one of the most promising video-based biometric technologies. The edge of silhouettes and motion are the most informative feature and previous studies have explored them separately and achieved notable results. However, due to occlusions and variations in viewing angles, their gait recognition performance is often affected by the predefined spatial segmentation strategy. Moreover, traditional temporal pooling usually neglects distinctive temporal information in gait. To address the aforementioned issues, we propose a novel gait recognition framework, denoted as GaitASMS, which can effectively extract the adaptive structured spatial representations and naturally aggregate the multi-scale temporal information. The Adaptive Structured Representation Extraction Module (ASRE) separates the edge of silhouettes by using the adaptive edge mask and maximizes the representation in semantic latent space. Moreover, the Multi-Scale Temporal Aggregation Module (MSTA) achieves effective modeling of long-short-range temporal information by temporally aggregated structure. Furthermore, we propose a new data augmentation, denoted random mask, to enrich the sample space of long-term occlusion and enhance the generalization of the model. Extensive experiments conducted on two datasets demonstrate the competitive advantage of proposed method, especially in complex scenes, i.e., BG and CL. On the CASIA-B dataset, GaitASMS achieves the average accuracy of 93.5% and outperforms the baseline on rank-1 accuracies by 3.4% and 6.3%, respectively, in BG and CL. The ablation experiments demonstrate the effectiveness of ASRE and MSTA. The source code is available at https://github.com/YanSun-github/GaitASMS
Nazeris biacuminatus Hu & Qiao 2019, sp. n.
No full textNazeris biacuminatus Hu & Qiao, sp. n. (Figs 5, 30–34) Type material. Holotype: CHINA: male, ‘ China: Guangxi Prov., Xing'an County, Mao'ershan N. R., 450–650 m, 25.VII.2012, Hu & Song leg.’ (SNUC). Paratypes: 1 female, same data as holotype. Description. Body length 6.2–7.3 mm; forebody length 3.6–3.7 mm. Body (Fig. 5) dark brown; antennae and legs yellowish brown. Head (Fig. 30) 1.03–1.05 times as long as wide; punctation very dense, moderately coarse, distinctly umbilicate and not confluent, interstices lacking microsculpture; postocular portion approximately 1.7 times as long as eye length. Pronotum (Fig. 30) 1.17–1.20 times as long as wide, approximately as long and 0.87–0.88 times as broad as head; punctation non-umbilicate, moderately dense and as coarse as that of head; midline posteriorly with very short and narrow impunctate elevation; interstices lacking microsculpture. Elytra (Fig. 30) 0.63–0.66 times as long as wide, 0.53–0.54 times as long and as broad as pronotum; punctation as dense and coarse as that of pronotum; interstices lacking microsculpture. Abdomen with punctation dense and rather coarse on tergites III–IV, dense and less coarse on tergite V–VI, moderately dense and fine on tergites VII–VIII; interstices lacking microsculpture. Male. Sternite VII (Fig. 31) with posterior margin nearly truncate in the middle. Sternite VIII (Fig. 32) with triangular posterior excision. Aedeagus (Figs 33, 34) weakly sclerotized; ventral process long, with pair of small laminae in basal third, apex divided into two straight branches in ventral view; dorso-lateral apophyses very slender and nearly straight, not reaching apex of ventral process. Distribution and habitat data. The species is known only from Mao'ershan in northeast Guangxi. The specimen was collected by sifting leaf litter at altitudes of 450– 650 m. Comparative notes. This species is most similar to N. exilis Hu & Li (Hu & Li 2017: 338, Figs 20–24) in general appearance and aedeagal characters, but can be separated by the truncate posterior margin of male sternite VII (Fig. 31), by the wider apical branches of ventral process of the aedeagus (Fig. 33), and by the straight and more slender dorso-lateral apophyses of aedeagus (Fig. 34). Etymology. The specific epithet (Latin, adjective: acuminate) alludes to the apically divided ventral process of aedeagus in ventral view.Published as part of Hu, Jia-Yao & Qiao, Yu-Jia, 2019, Five new species of Nazeris Fauvel in Guangxi, China (Coleoptera, Staphylinidae, Paederinae), pp. 431-441 in Zootaxa 4543 (3) on pages 438-439, DOI: 10.11646/zootaxa.4543.3.8, http://zenodo.org/record/261791
Multiuser Decorrelating Based Long-Range Frequency-Domain Channel Transfer Function Prediction in Multicarrier DS-CDMA Systems
No full textIn this contribution, multiuser decorrelating based frequency-domain channel estimation and long range channel prediction techniques are proposed for a generalized Multicarrier DS-CDMA (MC DS-CDMA) system communicating over a fast fading and frequency selective channel. In the MC DS-CDMA system considered, the channel transfer function (CTF) is estimated in the frequency-domain with the aid of pilot symbols by invoking the multiuser decorrelating based channel estimation technique, in order to reduce the effects of both the Multiuser Interference (MUI) and the background noise. Then, Kalman filter assisted long-range channel prediction is carried out with the aid of both the current and previous frequency-domain CTFs for the sake of predicting the future CTFs. Furthermore, a sinc-interpolator is employed for the sake of deriving the frequency-domain CTFs associated with the data symbols. Our simulation results show that for a reasonable signal-to-noise ratio (SNR) value the proposed frequency-domain multiuser decorrelating based channel estimator is robust to the effects of both the MUI as well as the noise
A Fourier-related FE2 Multiscale Model for Instability Phenomena of Long Fiber Reinforced Materials
No full textPerformance Evaluation of Distributed-Antenna Communications Systems Using Beam-Hopping
No full textDigital beamforming (DBF) techniques are capable of improving the performance of communications systems significantly. However, if the transmitted signals are conflicted with strong interference, especially, in the direction of the transmitted beams , these directional jamming signals will severely degrade the system performance. In order to efficiently mitigate the interference of the directional jammers, in this contribution a beam-hopping (BH) communications scheme is proposed. In the proposed BH communications scheme, only one pair of the beams is used for transmission and it hops from one to the next according to an assigned BH pattern. In this contribution a range of expressions in terms of the average SINR performance have been derived, when both the uplink and downlink are considered. The average SINR performance of the proposed BH scheme and that of the conventional single-beam (SB) as well as multiple-beam (MB) assisted beam-processing schemes have been investigated. Our analysis and results show that the proposed BH scheme is capable of efficiently combating the directional jamming, with the aid of utilizing the directional gain of the beams generated by both the transmitter and the receiver. Furthermore, the BH scheme is capable of reducing the intercept probability of the communications. Therefore, the proposed BH scheme is suitable for communications, when several distributed antenna arrays are available around a mobile
Nazeris yuyimingi Hu & Qiao 2019, sp. n.
No full textNazeris yuyimingi Hu & Qiao, sp. n. (Figs 4, 25–29) Type material. Holotype: CHINA: male, ‘ China: Guangxi, Xing'an County, Mao'ershan, 25°53'7''N, 110°29'14''E, beech forest, mixed leaf litter, humus, sifted, 1143 m, 31.VII.2014, Peng, Song, Yu & Yan leg.’ (SNUC). Description. Body length 6.1 mm; forebody length 3.3 mm. Body (Fig. 4) dark brown; antennae and legs yellowish brown. Head (Fig. 25) approximately as long as wide; punctation very dense, moderately coarse, distinctly umbilicate and partly confluent, interstices lacking microsculpture; postocular portion approximately 1.8 times as long as eye length. Pronotum (Fig. 25) 1.18 times as long as wide, 1.05 times as long and 0.90 times as broad as head; punctation non-umbilicate, moderately dense and as coarse as that of head; midline posteriorly with very short and narrow impunctate elevation; interstices lacking microsculpture. Elytra (Fig. 25) 0.61 times as long as wide, 0.53 times as long and as broad as pronotum; punctation as dense as, and less coarse than that of pronotum; interstices lacking microsculpture. Abdomen with punctation dense and rather coarse on tergites III, dense and less coarse on tergite VI–V, moderately dense and fine on tergites VI–VIII; interstices lacking microsculpture. Male. Sternite VII (Fig. 26) with posterior margin shallowly concave in the middle. Sternite VIII (Fig. 27) with V-shaped posterior excision. Aedeagus (Figs 28, 29) moderately sclerotized; ventral process long, dorsal parts slightly widened near middle and apex in ventral view, with pair of triangular basal laminae ventrally; dorso-lateral apophyses slender, slightly widened near apex in ventral view, extending slightly beyond apex of ventral process. Distribution and habitat data. The species is known only from Mao'ershan in northeast Guangxi. The specimen was collected by sifting leaf litter at an altitude of 1143 m. Comparative notes. The new species is similar in general appearance and aedeagal characters to N. chenyanae Hu & Li (Hu & Li 2017: 340, Figs 25–29), but can be separated by the shallowly concaved male sternite VII (Fig. 26), and by the narrower ventral process and the wider apex of dorso-lateral apophyses of aedeagus (Fig. 28). Etymology. The species is named in honor of Yi-Ming Yu, who collected some of the type specimens.Published as part of Hu, Jia-Yao & Qiao, Yu-Jia, 2019, Five new species of Nazeris Fauvel in Guangxi, China (Coleoptera, Staphylinidae, Paederinae), pp. 431-441 in Zootaxa 4543 (3) on pages 436-437, DOI: 10.11646/zootaxa.4543.3.8, http://zenodo.org/record/261791
A Novel FE2 Method Based Fourier Macroscopic Model for Instability Phenomena of Long Fiber Reinforced Composites
No full textNazeris furcatus Hu, Li & Zhao, sp. nov.
No full textNazeris furcatus Hu, Li & Zhao, sp. nov. (Figs. 2, 18– 22) Type material. Holotype: CHINA: Zhejiang Prov.: ɗ, Wenzhou City, Taishun County, Wuyanling, 700 m, 9.V. 2004, HU Jia-Yao, TANG Liang & ZHU Li-Long leg. Paratypes: CHINA: Zhejiang Prov.: 4 ΨΨ, same data as holotype; 5 ɗɗ, 4 ΨΨ, Wenzhou City, Taishun County, Wuyanling, 700 m, 20.VIII. 2004, HU Jia-Yao, TANG Liang & ZHU Li-Long leg.; 3 ɗɗ, Wenzhou City, Taishun County, Wuyanling, 700 m, 23.VIII. 2004, HU Jia-Yao, TANG Liang & ZHU Li-Long leg.; 6 ɗɗ, 3 ΨΨ, Wenzhou City, Taishun County, Wuyanling, 1000–1300 m, 24.VIII. 2004, HU Jia-Yao, TANG Liang & ZHU Li-Long leg. Description. Body length: 5.2–6.2 mm; forebody length: 3.0– 3.3 mm. Body (Fig. 2) elongate, brown, with labrum, coxae and two basal antennal segments reddish yellow; the remaining antennal segments, maxillary palpi and legs except for coxae yellow. Head suborbicular, slightly longer than broad (length/width = 1.05); postocular portion 1.69 times as long as eye length; on disk intervals between punctures flat, not raised like carinae. Antennae slender, extending to basal 1 / 3 of pronotum; relative length of each segment from 1 to 11: 21.0: 6.0: 13.5: 10.5: 9.5: 9.5: 9.5: 8.5: 7.5: 7.0: 9.0; relative width of each segment from 1 to 11: 5.0: 3.5: 3.0: 3.0: 3.0: 3.0: 3.0: 3.0: 3.0:3.0: 4.0. Pronotum convex and oval, longer than wide (length/width = 1.19), narrower (pronotum/head = 0.89) than and as long as head; prosternum with strong longitudinal median carina not reaching its anterior margin. Elytra as long as wide, distinctly shorter (elytra/pronotum = 0.82) and slightly narrower (elytra/pronotum = 0.97) than pronotum. Abdomen with fine and faint microsculpture only on apical 1 / 3 of 7 th tergite. Male. Seventh sternite (Fig. 18) slightly and widely emarginate in the middle of posterior margin; 8 th sternite (Fig. 19) widely and triangularly excised in the middle of posterior margin. Aedeagus (Figs. 20–22) distinctly sclerotized; median lobe in dorsal view distinctly bifurcate at apex, with pair of finger-like outward processes in apical 1 / 3, in lateral view curved ventrad subapically; dorso-lateral apophyses stout in basal half and much thinner in apical half, cone-shaped, projecting inwards at middle, extending beyond apex of median lobe. Female. Seventh and 8 th sternites simple. Remarks. The present new species can be easily distinguished from all the known species of Nazeris by the distinct shape of the aedeagus, particularly the apically bifurcate median lobe and the cone-shaped dorso-lateral apophyses (Fig. 20). Distribution. China (Zhejiang Prov.). Etymology. The species name is the Latin adjective “ furcatus ” (forked) referring to the distinct shape of the median lobe.Published as part of Hu, Jiayao, Li, Lizhen & Zhao, Meijun, 2011, Twelve new species of the Genus Nazeris Fauvel from Zhejiang Province, China (Coleoptera, Staphylinidae, Paederinae), pp. 1-20 in Zootaxa 2797 on pages 3-5, DOI: 10.5281/zenodo.20768
Nazeris yanzhuqii Hu & Qiao 2019, sp. n.
No full textNazeris yanzhuqii Hu & Qiao, sp. n. (Figs 6, 35–39) Type material. Holotype: CHINA: male, ‘ China: Guangxi Prov., Xing'an County, Mao'ershan N. R., alt. 2000– 2140 m, 9–11.VII.2011, Chen, Peng, Ma & Zhu leg.’ (SNUC). Paratypes: 10 males, 2 females, same data as holotype; 5 males, 5 females, same data, except ‘ 10.VII.2011, Zhong Peng leg. ’; 1 male, 4 females, same data, except ‘ 2100 m, 10.VII.2011, Tang & He leg. ’; 1 male, 1 female, same data, except ‘ 2100 m, 9–10.VII.2011, Tang L. & He W.-J. leg.’; 3 females, same data, except ‘ 2100 m, 10.VII.2011, Tang L. & He W.-J. leg.’; 2 males, 1 female, same data, except ‘ 2000 m, 11.VII.2011, Tang & He leg. ’; 4 males, 11 females, same data, except ‘ 2000– 2100 m, 22.VII.2012, Hu & Song leg. ’; 3 males, 3 females, same data, except ‘ 1950–2000 m, 23.VII.2012, Hu & Song leg. ’; 8 males, 6 females, same data, except ‘ 25°52'27''N, 110°24'44''E, beech forest, mixed leaf litter, humus, sifted, 1940 m, 29.VII.2014, Peng, Song, Yu & Yan leg. ’. Description. Body length 4.5–5.6 mm; forebody length 2.5–2.9 mm. Body (Fig. 6) dark brown; antennae and legs yellowish brown. Head (Fig. 35) 0.95–0.99 times as long as wide; punctation dense and coarse, non-umbilicate, interstices lacking microsculpture; postocular portion approximately twice as long as eye length. Pronotum (Fig. 35) 1.11–1.15 times as long as wide, 0.92–0.97 times as long and 0.78–0.83 times as broad as head; punctation as dense and as coarse as that of head; midline with very narrow or without impunctate elevation in posteriorly half; interstices lacking microsculpture. Elytra (Fig. 35) 0.68–0.74 times as long as wide, 0.58–0.63 times as long and 0.95–1.00 times as broad as pronotum; punctation as dense and slightly finer than that of pronotum; interstices lacking microsculpture. Abdomen with punctation dense and rather coarse on tergites III–V, dense and less coarse on tergite VI, moderately dense and fine on tergites VII–VIII; interstices lacking microsculpture. Male. Sternite VII (Fig. 36) with posterior margin truncate at middle. Sternite VIII (Fig. 37) with triangular posterior excision. Aedeagus (Figs 38, 39) well sclerotized; ventral process wide, with parallel sides, with narrowly incised apex in ventral view, and with pair of small triangular basal laminae ventrally; dorso-lateral apophyses widened near middle in ventral view, extending beyond apex of ventral process. Distribution and habitat data. The species is known only from Mao'ershan in northeast Guangxi. The specimen was collected by sifting leaf litter at altitudes of 1940–2140 m. Comparative notes. This species is most similar to N. alatus Hu & Li (Hu & Li 2017: 337, Figs 15–19) in general appearance and aedeagal characters, but can be separated by the impunctate elevation of the pronotum very narrow or absent (Fig. 35), by the longer and wider ventral process of the aedeagus, with much smaller basal laminae (Fig. 38), and by the wider dorso-lateral apophyses of aedeagus (Figs 38, 39). Etymology. The specific epithet is dedicated to Zhu-Qi Yan, who collected some of the type specimens.Published as part of Hu, Jia-Yao & Qiao, Yu-Jia, 2019, Five new species of Nazeris Fauvel in Guangxi, China (Coleoptera, Staphylinidae, Paederinae), pp. 431-441 in Zootaxa 4543 (3) on page 439, DOI: 10.11646/zootaxa.4543.3.8, http://zenodo.org/record/261791
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