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Automated Machine Learning Algorithm Using Recurrent Neural Network to Perform Long-Term Time Series Forecasting

computers, Materials & continua 2024年第3期78卷 3529-3549页

作者： Ying Su Morgan c.wang Shuai Liu Department of Statistics and Data Science University of Central FloridaOrlandoFL32816-2370USA School of Mathematics and Statistics Beijing Technology and Business UniversityBeijing100048China

Long-term time series forecasting stands as a crucial research domain within the realm of automated machine learning(AutoML).At present,forecasting,whether rooted in machine learning or statistical learning,typically relies on expert input and necessitates substantial manual *** manual effort spans model development,feature engineering,hyper-parameter tuning,and the intricate construction of time series *** complexity of these tasks renders complete automation unfeasible,as they inherently demand human intervention at multiple *** surmount these challenges,this article proposes leveraging Long Short-Term Memory,which is the variant of Recurrent Neural Networks,harnessing memory cells and gating mechanisms to facilitate long-term time series ***,forecasting accuracy by particular neural network and traditional models can degrade significantly,when addressing long-term time-series ***,our research demonstrates that this innovative approach outperforms the traditional Autoregressive Integrated Moving Average(ARIMA)method in forecasting long-term univariate time *** is a high-quality and competitive model in time series prediction,and yet it requires significant preprocessing *** multiple accuracy metrics,we have evaluated both ARIMA and proposed method on the simulated time-series data and real data in both short and long ***,our findings indicate its superiority over alternative network architectures,including Fully connected Neural Networks,convolutional Neural Networks,and Nonpooling convolutional Neural *** AutoML approach enables non-professional to attain highly accurate and effective time series forecasting,and can be widely applied to various domains,particularly in business and finance.

关键词： Automated machine learning autoregressive integrated moving average neural networks time series analysis

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Ballistic current induced effective force on magnetic domain wall

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Nano-Micro Letters 2009年第1期1卷 34-39页

作者： c.wang K.Xia Department of Physics Beijing Normal University

The collective dynamics of magnetic domain wall under electric current is studied in the form of spin transfer torque(STT). The out-of-plane STT induced effective force is obtained based on the Landau-Lifshitz-Gilbert(LLG) equation including microscopic STT terms. The relation between microscopic calculations and collective description of the domain wall motion is established. With our numerical calculations based on tight binding free electron model, we find that the non adiabatic out-of-plane torque components have considerable non-local properties. It turns out that the calculated effective forces decay significantly with increasing domain wall widths.

关键词： Magnetic domain Spin Transfer torque Spintronics First principle study

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用甲胎蛋白及钆塞酸增强MRI特征对亚厘米肝细胞肝癌的诊断算法

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国际医学放射学杂志 2024年第3期 377-378页

作者： P.Huang F.Wu K.Hou c.Zhou Y.Xiao c.wang 吴玉平

摘要目的探讨血清甲胎蛋白（AFP）在钆塞酸增强MRI(EOB-MRI)上诊断亚厘米肝细胞癌（Hcc）中的作用。方法回顾性纳入2017年1月—2023年3月在EOB-MRI上进行

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Flow resistance of gravel bed channels

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International Journal of Sediment Research 2014年第1期29卷 126-132页

作者： Wen c.wang David R.DAWDY Multech Engineering consultants

Existing resistance formulas produce a wide range of friction-factor estimates for gravel bed *** purpose of this paper is to develop a reliable resistance formula in terms of the Darcy-Weisbach friction factor/ Published data were screened and used to establish the *** existing formulas have considered that/is a function of relative roughness D84/R only,where R is the hydraulic radius and D84is the particle size referred to the intermediate diameter that equals or exceeds that of 84 percent of bed *** this paper,/is considered as a function of Froude number in addition to the relative roughness./for D84/R>1 displays a different trend than that for D84/Rc velocity distribution for D84/R>***/formula for D84/R<1 has been established.

关键词： Flow resistance Darcy-Weisbach friction factor Relative roughness Relative submergence Gravel bed channels Open channels

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Mechanisms of ultraviolet disinfection and chlorination of Escherichia coli： culturability, membrane permeability,metabolism, and genetic damage

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Journal of Environmental Sciences 2018年第3期30卷 356-366页

作者： Limei Xu chongmiao Zhang Pengcheng Xu Xiaochang c.wang International Science and Technology cooperation center for Urban Alternative Water Resources Development China Key Laboratory of Northwest Water Resource Environment and Ecology MOE China Engineering Technology Research center for Wastewater Treatment and Reuse Shaanxi Province China School of Environmental and Municipal Engineering Xi'an University of Architecture and Technology Xi'an 710055 China

Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after *** selection of a strict method is crucial for the evaluation of disinfection *** actions of 2 typical disinfectants–ultraviolet（UV）and chlorine–on the fecal indicator Escherichia coli were investigated by the detection of culturability,membrane permeability,metabolic activity,deoxyribonucleic acid（DNA）,and messenger ribonucleic acid（m RNA）.During UV disinfection,the irreversible damages in the cell membrane and cellular adenosine triphosphate（ATP）were negligible at low UV doses（80 m J/cm^2）.However,membrane permeability was damaged at low doses of chlorine（5 mg/L）,leading to leakage of cellular *** study showed that a slight lesion in DNA was detected even at high doses of UV（400 m J/cm^2）and chlorine（5 mg/L）*** decay of m RNA was more rapid than that of *** degradation level of m RNA depended on the choice of target *** exposure to 50 m J/cm^2UV dose or 5 mg/L chlorine for30 min,the DNA damage repair function（Rec A m RNA）was *** m RNA involved in the DNA damage repair function can be a potential indicator of bacterial viability.

关键词： UV chlorination Membrane damage Adenosine triphosphate DNA mRNA

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Two-dimensional correlation spectroscopic analysis on the interaction between humic acids and aluminum coagulant

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Journal of Environmental Sciences 2018年第2期30卷 181-189页

作者： Pengkang Jin Jina Song Xiaochang c.wang Xin Jin School of Environmental and Municipal Engineering Xi'an University of Architecture and Technology college of Energy and Environmental Engineering Hebei University of Engineering

In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by ***, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of cOOH〉 cOO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl c／OH at p H 5, and cOO-〉aliphatic hydroxyl c／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.

关键词： Two-dimensional correlation spectroscopy Al-HA complex Surface complexation Interaction sequence

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Thermodynamic prediction and experimental investigation of short-term dynamic membrane formation in dynamic membrane bioreactors:Effects of sludge properties

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Journal of Environmental Sciences 2019年第3期31卷 85-96页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang c.wang Key Lab of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology cooperation center for Urban Alternative Water Resources Development Key Lab of Environmental Engineering Shaanxi Province

In dynamic membrane bioreactors(DMBRs), a dynamic membrane(DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR using nylon mesh(25 μm) as support material to filtrate sludge suspensions of variable properties from three different sources to evaluate the effects on the short-term DM formation process(within 240 min). Furthermore, the extended Derjaguin–Landau–Verwey–Overbeek(XDLVO) theory was applied to analyze the sludge adhesion and cohesion behaviors on the mesh surface to predict quantitative parameters of the short-term DM formation process(including initial formation and maturation stage). The filtration results showed that the order of the initial DM formation time(permeate turbidity cator) was as follows: sludge with poor settleability and dewaterability cculability. Moreover, normal sludge(regarding settleability, dewaterability,flocculability, and extracellular polymeric substance) showed a more acceptable DM formation performance(short DM formation time, low permeate turbidity, and high permeate flux) than sludge with poor settleability, dewaterability and flocculability. The influence of sludge properties on the initial DM formation time corroborates the prediction of sludge adhesion behaviors by XDLVO theory. Additionally, the XDLVO calculation results showed that acid–based interaction, energy barrier, and secondary energy minimum were important determinants of the sludge adhesion and cohesion behaviors. Therefore, short-term DM formation process may be enhanced to achieve stable long-term DMBR operation through positive modification of the sludge properties.

关键词： Dynamic membrane bioreactor Dynamic membrane formation XDLVO theory Sludge properties Wastewater treatment

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Application of a hybrid gravity-driven membrane filtration and dissolved ozone flotation(MDOF)process for wastewater reclamation and membrane fouling mitigation

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Journal of Environmental Sciences 2019年第7期31卷 17-27页

作者： Xin Jin Wei wang Shuai wang Pengkang Jin Xiaochang c.wang Wushou Zhang Weijun An Yong wang Key Lab of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology Langzheng Environmental Protection Technology co. Ltd.

This study proposed a novel membrane filtration and dissolved ozone flotation integrated(MDOF) process and tested it at pilot scale. Membrane filtration in the MDOF process was operated in gravity-driven mode, and required no backwashing, flushing, or chemical cleaning. Because ozone was added in the MDOF process, ozonation, coagulation, and membrane filtration could occur in a single reactor. Moreover, in situ ozonation occurred in the MDOF process, which differs from the conventional pre-ozonation membrane filtration process. Significant enhancement of turbidity removal was further achieved through the addition of membrane filtration. Membrane fouling was mitigated in the MDOF process compared to the MDAF process. In situ ozonation in the MDOF process decreased the fluorescence intensity and transformed the high MW dissolved organics into small MW compounds. For the fouling layer, the extracellular polymeric substance(EPS) contents and cake layer morphology were analyzed. The results indicated that the contents of EPS decreased. Furthermore, a thinner and more loosely structured cake layer formed in the MDOF process. Because coagulation and ozonation occurred simultaneously in a single reactor, the generation of hydroxyl radicals was enhanced through the catalytic effect of Al-based coagulants on ozone decomposition, which further alleviated membrane fouling in the MDOF process.

关键词： Dissolved ozone flotation Gravity-driven membrane filtration Membrane fouling In situ ozonation

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Dynamic membrane bioreactor performance enhancement by powdered activated carbon addition:Evaluation of sludge morphological,aggregative and microbial properties

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Journal of Environmental Sciences 2019年第1期31卷 73-83页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang c.wang Huu Hao Ngo Key Lab of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology cooperation center for Urban Alternative Water Resources Development Key Lab of Environmental Engineering centre for Technology in Water and Wastewater School of Civil and Environmental Engineering University of Technology Sydney

The effects of powdered activated carbon(PAc) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor(DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAc-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane(DM) layer. Additionally, PAc addition did not exert very significant influence on the propagation of eukaryotes(protists and metazoans)and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAc improved the bacterial diversity in activated sludge, as PAc addition brought about additional microenvironment in the form of biological PAc(BPAc), which promoted the enrichment of Acinetobacter(13.9%), comamonas(2.9%), Flavobacterium(0.31%) and Pseudomonas(0.62%), all contributing to sludge flocs formation and several(such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAc addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.

关键词： Dynamic membrane bioreactor Powdered activated carbon Sludge property Filtration performance Wastewater treatment Microbial community

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Tracking the reactivity of ozonation towards effluent organic matters from WWTP using two-dimensional correlation spectra

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Journal of Environmental Sciences 2019年第2期31卷 289-298页

作者： Xin Jin Weijie Zhang Rui Hou Pengkang Jin Jina Song Xiaochang c.wang School of Environmental and Municipal Engineering Xi'an University of Architecture and Technology

The characteristics of effluent organic matter(EfOM) from a wastewater treatment plant(WWTP) during ozonation were investigated using excitation and emission matrix(EEM)spectra, Fourier transform infrared spectroscopy(FT-IR) and high-performance size exclusion chromatography(HPSEc) at different ozone dosages. The selectivity of ozonation towards different constituents and functional groups was analysed using two-dimensional correlation spectra(2D-cOS) probed by FT-IR, synchronous fluorescence spectra and *** results indicated that ozonation can destroy aromatic structures of EfOM and change its molecular weight distribution(MWD). According to 2D-cOS analysis, microbial humiclike substances were preferentially removed, and then the protein-like fractions. Terrestrial humic-like components exhibited inactivity towards ozonation compared with the above two fractions. Protein-like substances with small molecular weight were preferentially reacted during ozonation based on 2D-cOS probed by HPSEc. In addition, the selectivity of ozone towards different functional groups of EfOM exhibited the following sequence:phenolic and alcoholic c\O groups > aromatic structures containing c_c double bonds >aliphatic c\H. X-ray photoelectron spectroscopy(XPS) further elucidated the preferential reaction of aromatic structures in EfOM during ozonation.

关键词： Ozonation Two-dimensional correlation spectra (2D-cOS) Effluent organic matter (EfOM) Selectivity

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