An Unequal Protection FEC Scheme for Video over Optical Access Networks

( Yingying Cao ),( Xue Chen ),( Liqian Wang ),( Xicong Li ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.6

In this paper, we propose an unequal protection physical coding sub-layer (PCS) forward error correction (FEC) scheme for efficient and high-quality transmission of video data over optical access networks. Through identifying and resolving the unequal importance of different video frames and passing this importance information from MAC-layer to PCS, FEC scheme of PCS can be adaptive to application-layer data. Meanwhile, we jointly consider the different channel situations of optical network unit (ONU) and improve the efficiency of FEC redundancy by channel adaptation. We develop a theoretical algorithm and a hardware method to achieve efficient FEC assignment for the proposed unequal protection scheme. The theoretical FEC assignment algorithm is to obtain the optimal FEC redundancy allocation vector that results in the optimum performance index, namely frame error rate, based on the identified differential importance and channel situations. The hardware method aims at providing a realistic technical path with negligible hardware cost increment compared with the traditional FEC scheme. From the simulation results, the proposed Channel and Application-layer data Adaptation Unequal Protection (CAAUP) FEC scheme along with the FEC ratio assignment algorithm and the hardware method illustrates the ability of efficient and high-quality transmission of video data against the random errors in the channel of optical access networks.

Risk Factors for Work-Related Musculoskeletal Disorders Among Intensive Care Unit Nurses in China: A Structural Equation Model Approach

Shuai Yang,Li Li,Liqian Wang,Jiaqi Zeng,Yinglan Li 한국간호과학회 2020 Asian Nursing Research Vol.14 No.4

Purpose: This study explored the direct and indirect effects of risk factors of work-related musculoskeletaldisorders (WRMDs) in nurses working in intensive care units (ICUs). Methods: A cross-sectional study design was used. ICU nurses from 28 tertiary hospitals in the Hunanand Guangdong provinces participated in a survey conducted via a self-reported online questionnaire. Astructural equation model was used to fit the data and to evaluate associations among WRMDs and riskfactors. Results: Valid questionnaire samples were submitted by 984 ICU nurses. The prevalence of WRMDswithin the previous year among ICU nurses was 96.8%. A valid structural equation model was constructed,and a good fit was shown: Chi-square value/degrees of freedom ¼ 2.248; comparative fitindex ¼ .931; normal fit index ¼ .905; goodness-of-fit index ¼ .978; adjusted goodness-of-fit index ¼.966; and root mean square error of approximation ¼ .036. All regression coefficients for direct effectreached significant levels (critical ratio > 1.96 and p < .05). In the structural equation model, theoccurrence of WRMDs was directly affected by the following: physical factors, risk perception, and jobstress. Physical factors and a safe environment indirectly affected WRMDs through risk perception andjob stress. The strongest correlations with WRMDs were physical factors. Conclusion: The model provided a new perspective for understanding the associations among physicalfactors, workplace safety environment, risk perception, job stress, and WRMDs. To improve the practicesetting of the ICU, efforts should be made to help prevent WRMDs from physical, psychosocial, andenvironmental factors.

Study on the Innovation Efficiency of China’s High - tech Industry Considering the Enterprise Nature

Li Qian,Wen-ping Wang,Ren-qiao Xiao 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

This paper applies the DEA model to measure the innovation efficiency of the regional high-tech industry, domestic, Hong Kong, Macao and Taiwan and foreign-invested enterprises in China between 2008 and 2014 .The results show that: (i) from the whole, if the differences in enterprise nature is not considered, the average innovation efficiency of China"s high-tech industry is 0.748, and the pure technical efficiency and scale efficiency have some space to improve. The industry efficiencies in central and western provinces are low. (ii) The average efficiency of China"s domestic, Hong Kong, Macao and Taiwan and foreign-invested enterprises are 0.476, 0.529 and 0.525 respectively, which are lower than traditional DEA efficiency significantly, the efficiency of domestic enterprises was the lowest, and it showed a slight increase during the examination period. There are some differences in the root causes of efficiency loss in each province. For example, domestic enterprises’ innovation efficiency in Beijing is low, et al.

A zonal hybrid approach coupling FNPT with OpenFOAM for modelling wave-structure interactions with action of current

Li, Qian,Wang, Jinghua,Yan, Shiqiang,Gong, Jiaye,Ma, Qingwei Techno-Press 2018 Ocean systems engineering Vol.8 No.4

This paper presents a hybrid numerical approach, which combines a two-phase Navier-Stokes model (NS) and the fully nonlinear potential theory (FNPT), for modelling wave-structure interaction. The former governs the computational domain near the structure, where the viscous and turbulent effects are significant, and is solved by OpenFOAM/InterDyMFoam which utilising the finite volume method (FVM) with a Volume of Fluid (VOF) for the phase identification. The latter covers the rest of the domain, where the fluid may be considered as incompressible, inviscid and irrotational, and solved by using the Quasi Arbitrary Lagrangian-Eulerian finite element method (QALE-FEM). These two models are weakly coupled using a zonal (spatially hierarchical) approach. Considering the inconsistence of the solutions at the boundaries between two different sub-domains governed by two fundamentally different models, a relaxation (transitional) zone is introduced, where the velocity, pressure and surface elevations are taken as the weighted summation of the solutions by two models. In order to tackle the challenges associated and maximise the computational efficiency, further developments of the QALE-FEM have been made. These include the derivation of an arbitrary Lagrangian-Eulerian FNPT and application of a robust gradient calculation scheme for estimating the velocity. The present hybrid model is applied to the numerical simulation of a fixed horizontal cylinder subjected to a unidirectional wave with or without following current. The convergence property, the optimisation of the relaxation zone, the accuracy and the computational efficiency are discussed. Although the idea of the weakly coupling using the zonal approach is not new, the present hybrid model is the first one to couple the QALE-FEM with OpenFOAM solver and/or to be applied to numerical simulate the wave-structure interaction with presence of current.

Patterning-Induced Ferromagnetism of Fe₃GeTe₂ van der Waals Materials beyond Room Temperature

Li, Qian,Yang, Mengmeng,Gong, Cheng,Chopdekar, Rajesh V.,N’Diaye, Alpha T.,Turner, John,Chen, Gong,Scholl, Andreas,Shafer, Padraic,Arenholz, Elke,Schmid, Andreas K.,Wang, Sheng,Liu, Kai,Gao, Nan,Admas American Chemical Society 2018 NANO LETTERS Vol.18 No.9

<P>Magnetic van der Waals (vdW) materials have emerged as promising candidates for spintronics applications, especially after the recent discovery of intrinsic ferromagnetism in monolayer vdW materials. There has been a critical need for tunable ferromagnetic vdW materials beyond room temperature. Here, we report a real-space imaging study of itinerant ferromagnet Fe<SUB>3</SUB>GeTe<SUB>2</SUB> and the enhancement of its Curie temperature well above ambient temperature. We find that the magnetic long-range order in Fe<SUB>3</SUB>GeTe<SUB>2</SUB> is characterized by an unconventional out-of-plane stripe-domain phase. In Fe<SUB>3</SUB>GeTe<SUB>2</SUB> microstructures patterned by a focused ion beam, the out-of-plane stripe domain phase undergoes a surprising transition at 230 K to an in-plane vortex phase that persists beyond room temperature. The discovery of tunable ferromagnetism in Fe<SUB>3</SUB>GeTe<SUB>2</SUB> materials opens up vast opportunities for utilizing vdW magnets in room-temperature spintronics devices.</P> [FIG OMISSION]</BR>

Building Asian climate change scenario by multi‐regional climate models ensemble. Part II: mean precipitation

Li, Qian,Wang, Shuyu,Lee, Dong‐,Kyou,Tang, Jianping,Niu, Xiaorui,Hui, Pinhong,Gutowski Jr., William J.,Dairaku, Koji,McGregor, John L.,Katzfey, Jack,Gao, Xuejie,Wu, Jia,Hong, Song‐,You,Wan Wiley 2016 International journal of climatology Vol.36 No.13

<P><B>ABSTRACT</B></P><P>Under the framework of an project ‘Building Asian Climate Change Scenarios by Multi‐Regional Climate Models Ensemble’, the ability of eight regional climate models and two fine‐resolution global climate models to reproduce late 20th century (1981–2000) precipitation climatology is assessed. Future precipitation change (2041–2060) under the A1B scenario is also quantified by applying four different ensemble methods: equal weighting, weighted mean (WM), reliability ensemble averaging (REA) and performance‐based ensemble averaging, after applying fourfold cross‐validation using observation and multi‐model‐simulated precipitation. The results indicate that the ensemble of simulated precipitation outperforms any single RCM in many aspects. Among the four ensemble approaches, the WM and REA methods show better skill in improving the simulation results, and are used for ensemble prediction of regional climate in Asia. Under the A1B scenario, the WM method estimates future precipitation change of approximately 0.2 mm day<SUP>−1</SUP> with less precipitation in northern and western China and northern India, and more precipitation in most other areas in Asia. The future annual precipitation will decrease by 0.1‐0.5 mm day<SUP>−1</SUP> in northern India, Pakistan and the central area of southern China. No significant change is found over eastern Kazakhstan, Mongolia, north‐central and western China.</P>