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A fast stereoscopic video coding algorithm based on JMVM

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Science china(Information Sciences) 2011年第6期54卷 1218-1226页

作者： DENG ZhiPin 1,2., JIA KeBin 1 , CHAN YuiLam 2., FU Changhong 2.& SIU WanChi 2.1 department of {2. Information & Control engineering, Beijing university of Technology, Beijing 10012., china 2.department of {2. Information engineering, hong kong polytechnic university, hong kong, china 1. department of electronic Information & Control {2. Beijing University of Technology Beijing 100124 China2. Department of Electronic Information Engineering Hong Kong Polytechnic University Hong Kong China

In order to exploit the intra-view and inter-view dependencies in stereo video coding, a fast joint motion and disparity estimation algorithm is proposed in this paper. An efficient search strategy based on the motion-disparity constraint is developed, in which both the motion and disparity vectors can be obtained simultaneously with low complexity. Moreover, a credible initial predictive vector set is designed with the aid of the temporal and spatial neighboring blocks so that the coding efficiency can be further enhanced. The experimental results demonstrate that the proposed algorithm can reduce more than 96% coding time compared with the JMVM full search with a negligible quality drop.

关键词： H.2.4 stereoscopic video coding disparity estimation motion estimation

Approximation algorithms for indefinite complex quadratic maximization problems

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Science china Mathematics 2010年第10期53卷 2697-2708页

作者： HUANG Yongwei1,& ZHANG Shuzhong2.1department of {2. and Computer engineering,The hong kong university of Science and Technology,Kowloon,hong kong,china 2.1} of Systems engineering and engineering Management,The Chinese university of hong kong,Shatin,hong kong,china 1. department of electronic and Computer {2. The Hong Kong University of Science and Technology Kowloon Hong Kong China2. Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Shatin Hong Kong China

In this paper,we consider the following indefinite complex quadratic maximization problem: maximize zHQz,subject to zk ∈ C and zkm = 1,k = 1,...,n,where Q is a Hermitian matrix with trQ = 0,z ∈ Cn is the decision vector,and m *** (1/log n) approximation algorithm is presented for such ***,we consider the above problem where the objective matrix Q is in bilinear form,in which case a 0.7118 cos mπ 2.pproximation algorithm can be *** the context of quadratic optimization,various extensions and connections of the model are discussed.

关键词： indefinite Hermitian matrix randomized algorithms approximation ratio semidefinite programming relaxation

Multiagent flocking with formation in a constrained environment

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控制理论与应用（英文版） 2010年第2期8卷 151-159页

作者： Yao LU 1 , Yi GUO 1 , Zhaoyang DONG 2.(1.department of Electrical and Computer engineering, Stevens Institute of Technology, Castle Point, Hoboken, NJ07030, USA {2. of Electrical engineering, hong kong polytechnic university, hong kong, china) department of Electrical and Computer engineering Stevens Institute of Technology Castle Point Hoboken USA department of Electrical engineering Hong Kong Polytechnic University Hong Kong China

We consider the problem of controlling a group of mobile agents to form a designated formation while flocking within a constrained environment. We first propose a potential field based method to drive the agents to move in connection with their neighbors, and regulate their relative positions to achieve the specific formation. The communication topology is preserved during the motion. We then extend the method to flocking with environmental constraints. Stability properties are analyzed to guarantee that all agents eventually form the desired formation while flocking, and flock safely without collision with the environment boundary. We verify our algorithm through simulations on a group of agents performing maximum coverage flocking and traveling through an unknown constrained environment.

关键词： Multiagent system Formation control Flocking

An Underwater Target Detection Algorithm Based on Attention Mechanism and Improved YOLOv7

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Computers, Materials & Continua 2024年第2期78卷 2829-2845页

作者： Liqiu Ren Zhanying Li Xueyu He Lingyan kong Yinghao Zhang College of Information Science and engineering Dalian Polytechnic UniversityDalian116034China

For underwater robots in the process of performing target detection tasks,the color distortion and the uneven quality of underwater images lead to great difficulties in the feature extraction process of the model,which is prone to issues like error detection,omission detection,and poor ***,this paper proposed the CER-YOLOv7(CBAM-EIOU-RepVGG-YOLOv7)underwater target detection *** improve the algorithm’s capability to retain valid features from both spatial and channel perspectives during the feature extraction phase,we have added a Convolutional Block Attention Module(CBAM)to the backbone *** Reparameterization Visual Geometry Group(RepVGG)module is inserted into the backbone to improve the training and inference *** Efficient Intersection over Union(EIoU)loss is also used as the localization loss function,which reduces the error detection rate and missed detection rate of the *** experimental results of the CER-YOLOv7 algorithm on the UPRC(Underwater Robot Prototype Competition)dataset show that the mAP(mean Average Precision)score of the algorithm is 86.1%,which is a 2.2.improvement compared to the *** feasibility and validity of the CER-YOLOv7 are proved through ablation and comparison experiments,and it is more suitable for underwater target detection.

关键词： Deep learning underwater object detection improved YOLOv7 attention mechanism

Experimental study on the effect of gaseous and particulate emission from an ethanol fumigated diesel engine

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Science china(Technological Sciences) 2010年第12期53卷 3294-3301页

作者： YAO ChunDe1, ZHANG ZhiHui1,2. CHEUNG ChenShun2.& XU GuangLan1 1 State Key Laboratory of Engines, Tianjin university, Tianjin 300072. china {2. of Mechanical engineering, The hong kong polytechnic university, hong kong, china 1. State Key Laboratory of Engines Tianjin University Tianjin 300072 China2. Department of Mechanical Engineering The Hong Kong Polytechnic University Hong Kong China

Experiments were conducted on a four-cylinder direct-injection diesel engine with 10% and 2.% of the engine load taken up by fumigation ethanol injected into the air intake of each cylinder, to investigate the gaseous, particulate mass (PM) emissions, and number concentration and size distribution of the engine under five engine loads at the maximum torque engine speed of 1800 r/min. The experimental results show that at low engine loads, the brake thermal efficiency (BTE) decreases with increase in fumigation ethanol; but at high engine loads, the BTE is not significantly changed by fumigation ethanol. Fumigation ethanol can effectively decrease in brake specific nitrogen oxides (BSNOx), particulate mass and number emissions but significantly increase in brake specific hydrocarbon (BSHC), brake specific carbon monoxide (BSCO) and proportion of BSNO/BSNO2. Also, the geometrical mean diameter of the particles (GMD) increases with increase in engine load but the diameter is not changed by fumigation ethanol in all cases.

关键词： diesel engine ethanol particulate number emissions

Characteristics of vertical ozone distribution in the lower troposphere in the Yangtze River Delta at Lin'an in the spring of 2.01

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Science china Earth Sciences 2005年第9期48卷 1519-1528页

作者： ZHENG Xiangdong1, CHAN Chuenyu2. CUI hong2. QIN Yu3, CHAN Loyan2. ZHENG Yongguang3 & LEE Yusiang2.1. Chinese Academy of Meteorological Sciences, Beijing 100081, china 2. {2. of Civil and Structural engineering, hong kong polytechnic university, Hung Hom, hong kong, china 3. {2. of Atmospheric Sciences, Peking university, Beijing 100871, china 1. Chinese Academy of Meteorological Sciences 100081 Beijing China 2. department of Civil and Structural engineering Hong Kong Polytechnic University Hung Hom Hong Kong China 3. department of Atmospheric Sciences Peking University 100871 Beijing China

We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obta... 详细信息

We analyzed vertical distributions of ozone (O3) in the lower troposphere (2. to April 13, 2.01. The results showed that the vertical O3 distributions are controlled by metrological conditions and the char- acteristics of O3 profiles are related to those of wet bulb potential temperature and wind field. O3 below 2.km showed that the strongest variability and enhanced O3 mixing ratios were associated with easterly winds that blow pollutants from the upwind source region of the Yangtze River Delta (YRD) region. Vertical O3 profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2. well-mixed type, (3) layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3 affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern china, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3 at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern china also lead to regional accumulation of O3 and high O3 mixing ratio at Lin’an. Long-range transport of O3 and pollutants from the Pearl River Delta in South china and in-situ O3 formation also resulted in elevated O3 mixing ratios at around 1 km altitudes and layered O3 distribution in the lower troposphere.

关键词： vertical ozone distribution, lower troposphere, Yangtze River Delta, Lin'an.

Microfluidic-based isolation of circulating tumor cells with high-efficiency and high-purity

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Chinese Chemical Letters 2024年第8期35卷 101-111页

作者： Feng Wu Xuemin kong Yixuan Liu Shuli Wang Zhong Chen Xu Hou Fujian engineering Research Center for Solid-State Lighting Department of Electronic ScienceSchool of Electronic Science and EngineeringXiamen UniversityXiamen 361005China College of Physics and New Energy Xuzhou University of TechnologyXuzhou 221018China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Physical Science and Technology Xiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361102China

The isolation of circulating tumor cells(CTCs)from complex biological samples is of paramount signifi-cance for advancing cancer diagnosis,prognosis,and ***,the low concentration of CTCs and nonspecific adhesion of white blood cells(WBCs)present challenges that hinder the efficiency and purity of captured ***-based strategies utilize precise fluid control at the micron level to incorporate specific micro/nanostructures or recognition molecules,enabling effective CTCs ***,by employing surface modification designs that exhibit exceptional anti-adhesion properties against WBCs,the purity of isolated CTCs can be further *** review offers an in-depth explo-ration of recent advancements,challenges,and opportunities associated with microfluidic-based CTCs iso-lation from biological ***,we will comprehensively introduce the microfluidic-based strate-gies for achieving high-efficiency CTCs isolation,which includes the morphological design of microchan-nels for physical force-based CTCs isolation and the specific modification of microchannel surfaces for affinity-based CTCs ***,a review of recent research advances in microfluidic-based high-purity CTCs isolation is presented,focusing on strategies that decrease the nonspecific adhesion of WBCs through surface micro-/nanostructure construction or chemical and biological ***,we will summarize the article by providing the prospective opportunities and challenges for the future development of microfluidic-based CTCs isolation.

关键词： Microfluidics Isolation Circulating tumor cells High-efficiency High-purity

Relationships among Sedentary Time,electronic Product Addiction,and Depression in Adolescents during the COVID-19 Epidemic:A Cross-Lagged Study

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International Journal of Mental Health Promotion 2024年第3期26卷 221-228页

作者： Feng Sheng Chen kong Chao Li Teaching department of Sports Qufu Normal UniversityQufu273165China Teaching department of Sports Shandong Management UniversityJinan250100China General Education Center Weifang Vocational CollegeWeifang262737China

Objective:This study was conducted to explore the relationships among sedentary behavior(SB),electronic product addiction(EPA),and depression(D)in adolescents during the COVID-19 ***:A total of 604 adolescents(including 309 girls and 2.5 boys aged 12.18)were selected from Qufu City,Shandong Province,china for three rounds of *** model was constructed using AMOS 2..0 software,and cross-lagged analysis was ***:SB at T1 can significantly positively predict SB and EPA at T2.p2.p2.can significantly predict SB and EPA at T3(p2.can significantly predict SB,EPA,and D at T3(p<0.05).Conclusions:SB and EPA are predictive factors for ***,SB can significantly positively predict D and indirectly predict D through the mediating effect of EPA.

关键词： COVID-19 electronic product addiction depression sedentary behavior

Reflections on the Mechanism of Calcium Phosphate Nucleation on Titanium in Simulated Body Fluids

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Journal of Materials Science & Technology 2005年第5期21卷 613-617页

作者： F.T.Chengdepartment of Applied Physics, The hong kong polytechnic university,{2., china department of Applied Physics Hong Kong Polytechnic University Hong Kong Hong Kong

The results and main findings of studies reported in the literature in relation to the deposition of calcium phosphate on Ti in simulated body fluids are summarized. The effects of the surface hydroxyl groups and the sign of surface charge on the nucleation of calcium phosphate are reviewed. One major controversy among the conclusions of different studies is the order of adsorption of the calcium ions and the phosphate ions in the initial stage of immersion. A simple model based on the amphoteric nature of the hydroxyl groups on Ti is proposed in an attempt to delineate the nucleation process for calcium phosphate on Ti in simulated body fluids. HPO4^2. ions interact with the hydroxyl groups via ion exchange and/or electrostatic attraction, and Ca^2. ions, via electrostatic attraction only. There is no preferential order of adsorption. Seemingly inconsistent results in different studies possibly arise from different prior treatments of the samples, which affect the adsorption properties.

关键词： Titanium Calcium phosphate Simulated body fluid Hydroxyl group Point of zero charge Surface charge