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Soft transmission of 3D video for low power and low complexity scenario

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Digital Communications and Networks 2023年第3期9卷 769-778页

作者： Ao Li Taihai Yang Wenxin Wu Lei Luo School of Communications and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing400065China School of Computer Science and Technology East China Normal UniversityShanghai200062China School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu611731China

Thanks to the rapid development of naked-eye 3D and wireless communication technology,3D video related applications on mobile devices have attracted a lot of attention.Nevertheless,the time-varying characteristics of the wireless channel is very challenging for conventional source-channel coding based transmission strategy.Also,the high complexity of source-channel coding based transmission scheme is undesired for low power mobile terminals.An advanced transmission scheme named Softcast was proposed to achieve efficient transmission performance for 2D image/video.Unfortunately,it cannot be directly applied to wireless 3D video transmission with high efficiency.This paper proposes a more efficient soft transmission scheme for 3D video with a graceful quality adaptation within a wide range of channel Signal-to-Noise Ratio(SNR).The proposed method first extends the linear transform to 4 dimensions with additional view dimension to eliminate the view redundancy,and then metadata optimization and chunk interleaving are designed to further improve the transmission performance.Meanwhile,a synthesis distortion based chunk discard strategy is developed to improve the overall 3D video quality under the condition of limited bandwidth.The experimental results demonstrate that the proposed method significantly improves the 3D video transmission performance over the wireless channel for low power and low complexity scenarios.

关键词： Softcast Low power 3D video Wireless

Modelling the impact of timelines of testing and isolation on disease control

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Infectious Disease Modelling 2023年第1期8卷 58-71页

作者： Ao Li Zhen Wang Seyed M.Moghadas Agent-Based Modelling Laboratory York UniversityTorontoOntarioM3J 1P3Canada

Testing and isolation remain a key component of public health responses to both persistent and emerging infectious diseases.Although the value of these measures have been demonstrated in combating recent outbreaks including the COVID-19 pandemic and monkeypox,their impact depends critically on the timelines of testing and start of isolation during the course of disease.To investigate this impact,we developed a delay differential model and incorporated age-since-symptom-onset as a parameter for delay in testing.We then used the model to compare the outcomes of reverse-transcription polymerase chain reaction(RT-PCR)and rapid antigen(RA)testing methods when isolation starts either at the time of testing or at the time of test result.Parameterizing the model with estimates of SARS-CoV-2 infection and diagnostic sensitivity of the tests,we found that the reduction of disease transmission using the RA test can be comparable to that achieved by applying the RT-PCR test.Given constraints and inevitable delays associated with sample collection and laboratory assays in RT-PCR testing post symptom onset,self-administered RA tests with short turnaround times present a viable alternative for timely isolation of infectious cases.

关键词： Testing Isolation Delay equations Simulations Turnaround time

Copper Isotope Fractionation during Basalt Leaching at 25℃ and pH=0.3,2

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Journal of Earth Science 2022年第1期33卷 82-91页

作者： Dandan li Sheng-Ao Liu State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

The geochemical cycling of copper in the hydrosphere and soil environments primarily involves the transport of Cu from rocks to rivers via weathering.Understanding the factors controlling Cu isotope fractionation during weathering is crucial for the purpose of using Cu isotopes as a tracer of geochemical cycling.Here,we performed acid-leaching experiments on natural basalts (BHVO-2 and GBW07105) and chalcopyrite in Erlenmeyer flasks at T=25℃ and different pH values (0.3 and 2).Our results reveal substantial Cu isotope fractionations (△^(65)Cu_(solution-initial)) between leachates (Cu_(solution)) and starting materials (Cu_(initial)).The leachates released from GBW07105 and chalcopyrite are consistently enriched in heavier Cu isotopes relative to the starting materials at pH=2.However,the δ^(65)Cu_(solution)values decrease to about-0.6‰first,then increase to>0 for BHVO-2 at pH=2 and GBW07105 at pH=0.3.Our results indicate that leaching of natural rocks by acidic liquids can produce both positive and negative Cu isotope fractionation,depending on pH values and the types of minerals in starting materials.X-ray power diffraction analysis (XRD) patterns reveal similar mineral assemblages between starting basalts and residues after each reaction round.The most likely mechanisms responsible for such Cu isotope fractionation are the relative rates of Cu oxidation at the surface and Cu release into solution,and the sequence of mineral dissolution.Our study represents an important step for future studies to use Cu isotopes to explain Cu isotopic variations in natural rocks and waters.

关键词： Cu isotopes isotope fractionation basalt chalcopyrite leaching

Testing High-Dimensional Nonparametric Behrens-Fisher Problem

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Journal of Systems Science & Complexity 2022年第3期35卷 1098-1115页

作者： MENG Zhen li Na YUAN ao Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Biostatistics Bioinformatics and BiomathematicsGeorgetown UniversityWashington 20057USA

For high-dimensional nonparametric Behrens-Fisher problem in which the data dimension is larger than the sample size,the authors propose two test statistics in which one is U-statistic Rankbased Test(URT)and another is Cauchy Combination Test(CCT).CCT is analogous to the maximumtype test,while URT takes into account the sum of squares of differences of ranked samples in different dimensions,which is free of shapes of distributions and robust to outliers.The asymptotic distribution of URT is derived and the closed form for calculating the statistical significance of CCT is given.Extensive simulation studies are conducted to evaluate the finite sample power performance of the statistics by comparing with the existing method.The simulation results show that our URT is robust and powerful method,meanwhile,its practicability and effectiveness can be illustrated by an application to the gene expression data.

关键词： Cauchy combination test nonparametric Behrens-Fisher problem rank-based test U-statistic

Effects of visual restoration on gait performance and kinematics of lower extremities in patients with age-related cataract

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Chinese Medical Journal 2023年第5期136卷 596-603页

作者： Mingxin ao Huijuan Shi Xuemin li Hongshi Huang Yingfang ao Wei Wang Department of Ophthalmology Beijing Key Laboratory of Restoration of Damaged Ocular NervePeking University Third HospitalBeijing 100191China Department of Sports Medicine Institute of Sports Medicine of Peking UniversityBeijing Key Laboratory of Sports InjuriesPeking University Third HospitalBeijing 100191China.

Background:Visual inputs are critical for locomotor navigation and sensorimotor integration in the elderly;however,the mechanism needs to be explored intensively.The present study assessed the gait pattern after cataract surgery to investigate the effects of visual restoration on locomotion.Methods:The prospective study recruited 32 patients(70.1±5.2 years)with bilateral age-related cataracts in the Department of Ophthalmology at Peking University Third Hospital from October 2016 to December 2019.The temporal-spatial gait parameters and kinematic parameters were measured by the Footscan system and inertial measurement units.Paired t-test was employed to compare data normally distributed and Wilcoxon rank-sum test for non-normally distributed.Results:After visual restoration,the walking speed increased by 9.3%(1.19±0.40 m/s vs.1.09±0.34 m/s,P=0.008)and exhibited an efficient gait pattern with significant decrease in gait cycle(1.02±0.08 s vs.1.04±0.07 s,P=0.012),stance time(0.66±0.06 s vs.0.68±0.06 s,P=0.045),and single support time(0.36±0.03 s vs.0.37±0.02 s,P=0.011).High amplitude of joint motion was detected in the sagittal plane in the left hip(37.6°±5.3°vs.35.5°±6.2°,P=0.014),left thigh(38.0°±5.2°vs.36.4°±5.8°,P=0.026),left shank(71.9°±5.7°vs.70.1°±5.6°,P=0.031),and right knee(59.1°±4.8°vs.56.4°±4.8°,P=0.001).The motor symmetry of thigh improved from 8.35±5.30%to 6.30±4.73%(P=0.042).Conclusions:The accelerated gait in response to visual restoration is characterized by decreased stance time and increased range of joint motion.Training programs for improving muscle strength of lower extremities might be helpful to facilitate the adaptation to these changes in gait.

关键词： Biomechanical phenomena Cataract Gait Rehabilitation Visual perception

Development of an ANN-based building energy model for information-poor buildings using transfer learning

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Building Simulation 2021年第1期14卷 89-101页

作者： Ao Li Fu Xiao Cheng Fan Maomao Hu Department of Building Services Engineering The Hong Kong Polytechnic UniversityHong KongChina Department of Construction Management and Real Estate College of Civil EngineeringShenzhen UniversityShenzhenChina Oxford e-Research Centre Department of Engineering Science University of OxfordOxfordUK

Accurate building energy prediction is vital to develop optimal control strategies to enhance building energy efficiency and energy flexibility.In recent years,the data-driven approach based on machine learning algorithms has been widely adopted for building energy prediction due to the availability of massive data in building automation systems(BASs),which automatically collect and store real-time building operational data.For new buildings and most existing buildings without installing advanced BASs,there is a lack of sufficient data to train data-driven predictive models.Transfer learning is a promising method to develop accurate and reliable data-driven building energy prediction models with limited training data by taking advantage of the rich data/knowledge obtained from other buildings.Few studies focused on the influences of source building datasets,pre-training data volume,and training data volume on the performance of the transfer learning method.The present study aims to develop a transfer learning-based ANN model for one-hour ahead building energy prediction to fill this research gap.Around 400 non-residential buildings’data from the open-source Building Genome Project are used to test the proposed method.Extensive analysis demonstrates that transfer learning can effectively improve the accuracy of BPNN-based building energy models for information-poor buildings with very limited training data.The most influential building features which influence the effectiveness of transfer learning are found to be building usage and industry.The research outcomes can provide guidance for implementation of transfer learning,especially in selecting appropriate source buildings and datasets for developing accurate building energy prediction models.

关键词： building energy prediction data-driven approach transfer learning neural network information poor buildings

Subjective assessment for an advanced driver assistance system:a case study in China

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Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2022年第2期5卷 112-122页

作者： Di ao Jialin li Department of Electromechanical Engineering Faculty of Science and TechnologyUniversity of MacaoMacao SARChina Department of Vehicle Engineering School of Automotive and Transportation EngineeringHefei University of TechnologyHefeiChina

Purpose–This study aims to propose a novel subjective assessment(SA)method for level 2 or level 21 advanced driver assistance system(ADAS)with a customized case study in China.Design/methodology/approach–The proposed SA method contains six dimensions,including perception,driveability and stability,riding comfort,human–machine interaction,driver workload and trustworthiness and exceptional operating case,respectively.And each dimension subordinates several subsections,which describe the corresponding details under this dimension.Findings–Based on the proposed SA,a case study in China is conducted.Six drivers with different driving experiences are invited to give their subjective ratings for each subsection according to a predefined rating standard.The rating results show that the ADAS from Tesla outperforms the upcoming electric vehicle in most cases.Originality/value–The proposed SA method is beneficial for the original equipment manufacturers developing related technologies in the future.

关键词： Level 2 or 21 Advanced driver assistance system Subjective assessment method Six dimensions Case study

Shell characterization and effects on cavity volume of wild Jinjiang oyster Crassostrea ariakensis in different estuaries of China

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Journal of Oceanology and limnology 2023年第5期41卷 2020-2031页

作者： Qi YANG Ao Li Luping WANG Rihao CONG Jianming YANG Guofan ZHANG Wei WANG li li Shandong Key Lab of Applied Mycology College of Life SciencesQingdao Agricultural UniversityQingdao 266109China CAS and Shandong Province Key Laboratory of Experimental Marine Biology Center for Ocean Mega-ScienceInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Fisheries Science and Food Production Processes Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China National and Local Joint Engineering Key Laboratory of Ecological Mariculture Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Biology and Biotechnology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

Jinjiang oyster Crassostrea ariakensis,a species with economic and ecological value,is distributed along the estuaries and coasts of East Asia.With the decline in natural resources,the conservation and aquaculture of this species is urgent.However,studies characterizing their shell shape remain scarce.We investigated the morphological differences in the shells of wild Jinjiang oysters from six populations(Qinzhou,Shanghai,Nantong,Qingdao,and Binzhou hard or muddy bottom)along the coast of China.The color of the shell and adductor muscle scar showed associations with temperature gradient along its geographical distribution.Oyster shape was defined by shell height to shell length ratio,and the ratio varies among geographic locations of the populations.They were found nearly round(Qinzhou and Nantong populations),oval(Qingdao and Binzhou populations),or water-droplet-shaped(Shanghai population).Binzhou populations living on muddy substrates are more elongated than those on hard substrate.In addition,we developed a method to measure the cavity volume in oysters.Correlation and path analysis showed that shell height significantly influenced cavity volume.The synergistic effect of the two factors(the height,length,and width of the shell in pairs)on the cavity volume resulted in differences between northern and southern groups:samples from the southern group(Qinzhou and Shanghai)showed correlation between shell height and shell width,while those from the northern group(Nantong,Qingdao,and Binzhou)showed correlation between shell height and shell length.All populations showed significant correlation between shell height and cavity height,and shell length and cavity length,while the correlation between shell width and cavity width was minimal,which may have been resulted from uneven shell thickness.The linear equation for shell height and cavity volume under different ratios of shell height to length was obtained.In this study,we determined that shell height has the most influence on cavity volume,and specific cavity volu

关键词： shell shape cavity volume correlation analysis path analysis Crassostrea ariakensis

Fractional Coloring Planar Graphs under Steinberg-type Conditions

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Acta Mathematica Sinica,English Series 2023年第5期39卷 904-922页

作者： Xiao Lan HU Jia Ao Li School of Mathematics and Statistics&Hubei Key Laboratory of Mathematical Sciences Central China Normal UniversityWuhan 430079P.R.China School of Mathematical Sciences and LPMC Nankai UniversityTianjin 300071P.R.China

A Steinberg-type conjecture on circular coloring is recently proposed that for any prime p≥5,every planar graph of girth p without cycles of length from p+1 to p(p-2)is Cp-colorable(that is,it admits a homomorphism to the odd cycle Cp).The assumption of p≥5 being prime number is necessary,and this conjecture implies a special case of Jaeger’s Conjecture that every planar graph of girth 2p-2 is Cp-colorable for prime p≥5.In this paper,combining our previous results,we show the fractional coloring version of this conjecture is true.Particularly,the p=5 case of our fractional coloring result shows that every planar graph of girth 5 without cycles of length from 6 to 15 admits a homomorphism to the Petersen graph.

关键词： Fractional coloring circular coloring planar graphs girth homomorphism