Fast Quadtree Structure Decision for HEVC Intra Coding Using Histogram Statistics

( Yuchen Li ),( Yitong Liu ),( Hongwen Yang ),( Dacheng Yang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.5

The final draft of the latest video coding standard, High Efficiency Video Coding (HEVC), was approved in January 2013. The coding efficiency of HEVC surpasses its predecessor, H.264/MPEG-4 Advanced Video Coding (AVC), by using only half of the bitrate to encode the same sequence with similar quality. However, the complexity of HEVC is sharply increased compared to H.264/AVC. In this paper, a method is proposed to decrease the complexity of intra coding in HEVC. Early pruning and an early splitting strategy are applied to the quadtree structure of coding tree units (CTU) and residual quadtree (RQT). According to our experiment, when our method is applied to sequences from Class A to Class E, the coding time is decreased by 44% at the cost of a 1.08% Bjontegaard delta rate (BD-rate) increase on average.

THE IMPACT OF BIG DATA ON BUSINESS MODEL INNOVATION OF TRADITIONAL INDUSTRY

Shenghui Wang,Yuchen Zhang,Tianzhu Li,Jing Fei Long 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

With the rapid development of science and technology, big data has been applied in many fields and has brought commercial revolution[1]. The scientific community generally regards big data as "massive data + complex types of data". Commercial applications are more concerned about big data as an analytical (prediction) method and focus on the potential commercialization of analysis results. All walks of life will produce large amounts of data every day. The transition of data-scale brings huge commercial value, which will certainly bring the innovation of business model[2]. Particularly in the internet and other emerging industries, because they get data more convenient and fast. Like Amason, Facebook, Google etc, they use analysis of big data to innovate their business model for maximizing their profits[3], actually business model refers to "an enterprise’s profitable operation mode plus ways to make money"[4]. So the effectiveness of business model innovation of big data on emerging industries has been remarkable. But the impact of big data on traditional industries is still in the exploratory stage. Traditional industry mainly refers to the labor intensive, manufacturing oriented industries, including the traditional commerce and service industry[5]. Learning from the experience of big data on business model innovation of emerging industries, traditional industries can use big data to subvert the business model and accelerate the transformation and upgrading.

Indirect displacement monitoring of high-speed railway box girders consider bending and torsion coupling effects

Xin Wang,Zhonglong Li,Yi Zhuo,Hao Di,Jianfeng Wei,Yuchen Li,Shunlong Li 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.6

The dynamic displacement is considered to be an important indicator of structural safety, and becomes an indispensable part of Structural Health Monitoring (SHM) system for high-speed railway bridges. This paper proposes an indirect strain based dynamic displacement reconstruction methodology for high-speed railway box girders. For the typical box girders under eccentric train load, the plane section assumption and elementary beam theory is no longer applicable due to the bend-torsion coupling effects. The monitored strain was decoupled into bend and torsion induced strain, pre-trained multi-output support vector regression (M-SVR) model was employed for such decoupling process considering the sensor layout cost and reconstruction accuracy. The decoupled strained based displacement could be reconstructed respectively using box girder plate element analysis and mode superposition principle. For the transformation modal matrix has a significant impact on the reconstructed displacement accuracy, the modal order would be optimized using particle swarm algorithm (PSO), aiming to minimize the ill conditioned degree of transformation modal matrix and the displacement reconstruction error. Numerical simulation and dynamic load testing results show that the reconstructed displacement was in good agreement with the simulated or measured results, which verifies the validity and accuracy of the algorithm proposed in this paper.

Ultimate behaviour and rotation capacity of stainless steel end-plate connections

Yuchen Song,Brian Uy,Dongxu Li,Jia Wang 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.4

This paper presents a combined experimental and numerical study on stainless steel end-plate connections, with an emphasis placed on their ultimate behaviour and rotation capacity. In the experimental phase, six connection specimens made of austenitic and lean duplex stainless steels are tested under monotonic loads. The tests are specifically designed to examine the close-to-failure behaviour of the connections at large deformations. It is observed that the rotation capacity is closely related to fractures of the stainless steel bolts and end-plates. In the numerical phase, an advanced finite element model suitable for fracture simulation is developed. The incorporated constitutive and fracture models are calibrated based on the material tests of stainless steel bolts and plates. The developed finite element model exhibits a satisfactory accuracy in predicting the close-to-failure behaviour of the tested connections. Finally, the moment resistance and rotation capacity of stainless steel end-plate connections are assessed based on the experimental tests and numerical analyses.

Green's additive complement problem for $k$-th powers

Yuchen Ding,Li-Yuan Wang 대한수학회 2022 대한수학회지 Vol.59 No.2

Let $k\geqslant 2$ be an integer, $S^k=\{1^k,2^k,3^k,\ldots\}$ and $B=\{b_1,b_2,b_3,\ldots\}$ be an additive complement of $S^k$, which means all sufficiently large integers can be written as the sum of an element of $S^k$ and an element of $B$. In this paper we prove that $$\limsup_{n\rightarrow \infty}\frac{\Gamma\left(2-\frac{1}{k}\right)^{\frac{k}{k-1}}\Gamma\left(1+\frac{1}{k}\right) ^{\frac{k}{k-1}}n^{\frac{k}{k-1}}-b_n}{n} \geqslant \frac{k}{2(k-1)}\frac{\Gamma\left(2-\frac{1}{k}\right)^2}{\Gamma\left(2-\frac{2}{k}\right)},$$ where $\Gamma(\cdot)$ is Euler's Gamma function.

Parameter Sensitivity Analysis of the WRF-Hydro Modeling System for Streamflow Simulation: a Case Study in Semi-Humid and Semi-Arid Catchments of Northern China

Yuchen Liu,Jia Liu,Chuanzhe Li,Fuliang Yu,Wei Wang,Qingtai Qiu 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.3

The WRF model is nowadays the most widely applied mesoscale numerical weather prediction model. Its land-surface hydrological modeling module, WRF-Hydro, which is designed to facilitate the land-surface modeling being coupled with WRF, draws more and more attentions from both the meteorological and the hydrological community. In this study, four sensitive and principle parameters of WRF-Hydro are tested in semi-humid and semi-arid areas of northern China. These parameters include the runoff infiltration parameter (REFKDT), the surface retention depth (RETDEPRT) controlled by a scaling parameter named RETDEPRTFAC, the channel Manning roughness parameter (MannN), and the overland flow roughness parameter (OVROUGHRT) controlled by the scaling parameter OVROUGHRTFAC. WRF-Hydro is designed with a 100-m horizontal grid spacing in two catchments of northern China. The performance of WRF-Hydro with different parameterisation combination schemes is tested for simulating a typical 24-h storm events with uniform rainfall evenness in space and time. The Nash-Sutcliffe efficiency and the root mean squared error of the simulated streamflow, together with the cumulative amount of the simulated rainfall is chosen as the evaluation statistics. It is found that REFKDT and MannN are the most sensitive parameter among the four parameters, and the case is especially evident with unsaturated soil conditions. In order to obtain the most reasonable value range, REFKDT and MannN are further verified by another three 24-h storm events with different spatial and temporal evenness. The range of REFKDT from 2.0 to 3.0, and the MannN scale factor from 1.5 to 1.8 is found to give the best results. The findings of this study can be used as references for calibration of the WRF-Hydro modeling system in semi-humid and semi-arid regions with similar rainfall-runoff response characteristics. The methodologies to design and test the combination schemes of parameterisations can also be regarded as a reference for evaluation of the WRF/WRF-Hydro coupled system for land-surface process modeling.

Sensorless Control of the Switched Reluctance Motor Based on the Sliding-Mode Observer

Li Xinyu,Liu Jiayu,Ge Lefei,Zhong Jixi,Huang Jiale,Zhao Yuchen,Song Shoujun 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

To upgrade the application of switched reluctance motors (SRMs) for more electric aircraft, this paper presents a method with sensorless control based on the flux-linkage data from the finite element method. First, a calibration strategy is employed to obtain the flux-linkage characteristics. Then, a sliding-mode observer is used to realize the sensorless control of the SRM. The proposed method only requires the flux-linkage of the SRM at aligned and unaligned rotor positions from the experiment which takes a low-measurement effort to get the rotor position and has better accuracy in position and speed estimation than the FEM. Experimental results verify the accuracy and effectiveness of the proposed method.

Assessment of titanium alloy bolts for structural applications

Dongxu Li,Brian Uy,Jia Wang,Yuchen Song 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.4

This paper explored the viability of utilising titanium alloy bolts in the construction industry through an experimental programme, where a total of sixty-six titanium alloy (Ti/6Al/4V) bolts were tested under axial tension, pure shear and combined tension and shear. In addition, a series of Charpy V-notch specimens machined from titanium alloy bolts, conventional high-strength steel bolts, austenitic and duplex stainless steel bolts were tested for impact toughness comparisons. The obtained experimental results demonstrated that the axial tensile and pure shear capacities of titanium alloy bolts can be reasonably estimated by the current design standards for steel structures (Eurocode 3, AS 4100 and AISC 360). However, under the combined tension and shear loading conditions, significant underestimation by Eurocode 3 and unsafe predictions through AS 4100 and AISC 360 indicate that proper modifications are necessary to facilitate the safe and economic use of titanium alloy bolts. In addition, numerical models were developed to calibrate the fracture parameters of the tested titanium alloy bolts. Furthermore, a design-based selection process of titanium alloy bolts in the structural applications was proposed, in which the ultimate strength, ductility performance and corrosion resistance (including galvanic corrosion) of titanium alloy bolts was mainly considered.

Enhanced photocatalytic performance of TiO2 nanowires by substituting noble metal particles with reduced graphene oxide

Fei Yuchen,Ye Xiaofang,Al-Baldawy Aseel Shaker,Wan Jing,Lan Jinshen,Zhao Jingtian,Wang Ziyun,Qu Shanzhi,Hong Rongdun,Guo Shengshi,Huang Shengli,Li Shuping,Kang Junyong 한국물리학회 2022 Current Applied Physics Vol.44 No.-

Noble metal particles have been embedded in semiconductors to improve photocatalysis efficiently, but the high cost made this approach difficult to apply widely in industry. Herein titanium dioxide/reduced graphene oxide (TiO2/rGO) nanowires in a core-shell structure were prepared. The physicochemical properties and photocatalytic performance of the specimen were characterized in comparison with TiO2 and TiO2/Pt nanowires. The rGO layer and Pt nanoparticles increased chemical states of the components, reduced bandgap energy of the nanowires, enhanced visible light absorption, improved conductance and capacitance significantly. The methylene blue as catalyzed by TiO2/Pt and TiO2/rGO nanowires was degraded to 7.9% and 8.4% in an hour, but retained 25.7% by the TiO2 nanowires. The properties and function of TiO2/rGO nanowires were close to those of TiO2/Pt nanowires, while the rGO price was much lower than that of Pt, which was of great significance for the photocatalytic application of TiO2 heterojunction materials in industry.

Behaviour and design of Grade 10.9 high-strength bolts under combined actions

Dongxu Li,Brian Uy,Jia Wang,Yuchen Song 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.3

The use of high-strength steel and concrete in the construction industry has been gaining increasing attention over the past few decades. With it comes the need to utilise high-strength structural bolts to ensure the design load to be transferred safely through joint regions, where the space is limited due to the reduced structural dimensions. However, research on the behaviour of high-strength structural bolts under various loading combinations is still insufficient. Most of the current design specifications concerning high-strength structural bolts were established based on a very limited set of experimental results. Moreover, as experimental programs normally include limited design parameters for investigation, finite element analysis has become one of the effective methods to assist the understanding of the behaviour of structural components. An accurate and simple full-range stress-strain model for high-strength structural bolts under different loading combinations was therefore developed, where the effects of bolt fracture was included. The ultimate strength capacities of various structural bolts obtained from the present experimental program were compared with the existing design provisions. Furthermore, design recommendations concerning the pure shear and tension, as well as combined shear and tension resistance of Grade 10.9 high-strength structural bolts were provided.