OPTIMAL SELECTION FOR THE WEIGHTED COEFFICIENTS OF THE CONSTRAINED VARIATIONAL PROBLEMS

The aim is to put forward the optimal selecting of weights in variational problemin which the linear advection equation is used as constraint. The selection of the functionalweight coefficients ( FWC) is one of the key problems for the relevant research. It wasarbitrary and subjective to some extent presently. To overcome this difficulty, thereasonable assumptions were given for the observation field and analyzed field, variationalproblems with " weak constraints" and " strong constraints" were considered separately. Bysolving Euler' s equation with the matrix theory and the finite difference method of partialdifferential equation, the objective weight coefficients were obtained in the minimumvariance of the difference between the analyzed field and ideal field. Deduction results showthat theoretically the optimal selection indeed exists in the weighting factors of the costfunction in the means of the minimal variance between the analysis and ideal field in terms ofthe matrix theory and partial differential ( corresponding difference ) equation, if thereasonable assumption from the actual problem is valid and the differnece equation is stable.It may realize the coordination among the weight factors, numerical models and theobservational data. With its theoretical basis as well as its prospects of applications, thisobjective selecting method is probably a way towards the finding of the optimal weightingfactors in the variational problem.

Retrieval Single-Doppler Radar Wind with Variational Assimilation Method-Part I: Objective Selection of Functional Weighting Factors

In variational problem, the selection of functional weighting factors (FWF) is one of the key points for discussing many relevant studies. To overcome arbitrariness and subjectivity of the empirical selecting methods used widely at present, this paper tries to put forward an optimal objective selecting method of FWF. The focus of the study is on the weighting factors optimal selection in the variation retrieval single-Doppler radar wind field with the simple adjoint models. Weighting factors in the meaning of minimal variance are calculated out with the matrix theory and the finite difference method of partial differential equation. Experiments show that the result is more objective comparing with the factors obtained with the empirical method.

Seasonal Variations in Birth Weight in Suzhou Industrial Park

Many environmental factors have been shown to adversely influence birth weight,and new insight has been gained into＇seasonal programming＇.We studied a total of 23,064 infants.The mean birth weight varied across seasons.Logistic regression analysis was used to obtain the crude and adjusted odds ratios（ORs）for dichotomous outcomes（e.g.,macrosomia,low birth weight）.

Spatial variation of the relationship between transport accessibility and the level of economic development in Qinghai-Tibet Plateau, China

As an important component of China’ transportation systems, for a long time, the insufficient performance of transport in QinghaiTibet Plateau(QTP) was a bottleneck restricting the economic growth and social development in this area. Nevertheless, the implementation of the western development strategy has accelerated the preliminary construction of comprehensive transport network since 2000. Due to the large area and significant geographical heterogeneity, there is a growing need to understand the relationship between transportation and economic development based on the perspective of spatial difference. By using GIS-based raster analysis and Geographically Weighted Regression(GWR) model, we investigated the spatial-temporal distribution of highway, railway and airport accessibility, respectively, and estimated the correlation and heterogeneity between transport accessibility and the level of economic development. Results revealed that:(1) Transport accessibility in the QTP improved by 53.38% in the past 15 years, which is specifically embodied in the improvement of both highway and railway.(2) Accessibility presented prominent differentiation in the space, increasing from west to east and reducing with the rise of elevation, specifically, the best accessibility area of the highway is below 4000 m above sea level, while the area with an altitude of over 4000 m has the lowest aviation time cost.(3) In general, the long weighted average time cost to critical transport facilities posed significantly negative effect on county economic growth in QTP, more positively, the adverse effect gradually weakened over time.(4) Obvious heterogeneity exists at the influence of different transport accessibility factors on the level of economic development, reflecting both in the horizontal space and altitudinal belt. Therefore, region-specific policies should be addressed for the sustainable development of transport facilities as well as economy in the west mountain areas.

A Unified Variational Principle of Fluid Mechanics and Application on Solitary Subdomain or Point

-According to basic equations of fluid mechanics, this paper presents a unified variational principle of fluid mechanics (UVPFM) by using the optimization method of weighted residuals (OMWR). The advantages are as follows, the establishment of the functional and the variational principle is easy, it can change various problems of fluid mechanics derived by basic equations into a unified optimization problem, and the solution is the optimum one in some sense. According to the OMWR for the solitary subdomain, this paper uses UVPFM onto any solitary subdomain and gives the solution of the hydrodynamics equation which is suitable only for that solitary subdomain. According to the OMWR for solitary point, this paper uses UVPFM to any solitary point and gives the solution of the hydrodynamics equation (point solution) which is suitable only for that solitary point. As the solution for the solitary subdomain or solitary point is developed independently, the compatibility with other subdomain or other points, does not need to be considered, but all the boundary conditions and the supplementary derived residual equations obtained by running the derivative operations to the differential equation should be taken into account.

Monthly gravity field recovery from GRACE orbits and K-band measurements using variational equations approach

The Gravity Recovery and Climate Experiment（GRACE） mission can significantly improve our knowledge of the temporal variability of the Earth＇s gravity field.We obtained monthly gravity field solutions based on variational equations approach from GPS-derived positions of GRACE satellites and K-band range-rate measurements.The impact of different fixed data weighting ratios in temporal gravity field recovery while combining the two types of data was investigated for the purpose of deriving the best combined solution.The monthly gravity field solution obtained through above procedures was named as the Institute of Geodesy and Geophysics（IGG） temporal gravity field models.IGG temporal gravity field models were compared with GRACE Release05（RL05） products in following aspects：（i） the trend of the mass anomaly in China and its nearby regions within 2005-2010; （ii） the root mean squares of the global mass anomaly during 2005-2010; （iii） time-series changes in the mean water storage in the region of the Amazon Basin and the Sahara Desert between 2005 and 2010.The results showed that IGG solutions were almost consistent with GRACE RL05 products in above aspects（i）-（iii）.Changes in the annual amplitude of mean water storage in the Amazon Basin were 14.7 ± 1.2 cm for IGG,17.1 ± 1.3 cm for the Centre for Space Research（CSR）,16.4 ± 0.9 cm for the GeoForschungsZentrum（GFZ） and 16.9 ± 1.2 cm for the Jet Propulsion Laboratory（JPL） in terms of equivalent water height（EWH）,respectively.The root mean squares of the mean mass anomaly in Sahara were 1.2 cm,0.9 cm,0.9 cm and 1.2 cm for temporal gravity field models of IGG,CSR,GFZ and JPL,respectively.Comparison suggested that IGG temporal gravity field solutions were at the same accuracy level with the latest temporal gravity field solutions published by CSR,GFZ and JPL.

Nemytskii Operator in the Space of Set-Valued Functions of Bounded <i>φ</i>-Variation

In this paper we consider the Nemytskii operator, i.e., the composition operator defined by (Nf)(t)=H(t,f(t)), where H is a given set-valued function. It is shown that if the operator N maps the space of functions bounded φ1-variation in the sense of Riesz with respect to the weight function αinto the space of set-valued functions of bounded φ2-variation in the sense of Riesz with respect to the weight, if it is globally Lipschitzian, then it has to be of the form (Nf)(t)=A(t)f(t)+B(t), where A(t) is a linear continuous set-valued function and B is a set-valued function of bounded φ2-variation in the sense of Riesz with respect to the weight.

基于局部-地理加权回归的时变谐波阻抗估计

现有研究中通常假定电力系统谐波阻抗恒定,但不符合真实工况中情况。实际中,系统侧谐波阻抗和背景谐波随运行工况时变,当两谐波电压样本点时间间隔较大时,对应时刻的阻抗和背景谐波的差值可能较大,难以根据时间间隔较远样本点的信息估计关注样本点的阻抗值。由此,文中提出一种基于局部-地理加权回归的时变系统侧谐波阻抗估计方法,首先依据时间间隔大小构建权重矩阵,对与关注样本点时间间隔较大的样本点赋予较小权重,并采用局部加权回归(locally weighted regression,LWR)初步估计系统侧谐波阻抗和背景谐波参考值。然后利用阻抗参考值修正回归方程以降低原回归方程的欠定程度,同时以背景谐波参考值为先验信息,筛选出与关注样本点背景谐波相似的样本点,再基于所筛选样本逐一采用地理加权回归(geographically weighted regression,GWR)求解各点的背景谐波电压和系统侧谐波阻抗。在强背景谐波波动的情况下,文中所提方法能识别阻抗的突变点、估计系统侧谐波阻抗的变化趋势。最后通过仿真分析可知,文中所提方法相对于传统恒定谐波阻抗估计方法,估计准确度提升约40%;相对于现有变阻抗估计方法,估计准确度提升约30%。

基于变异系数法的沙颍河上游干流生态基流价值变化研究

为了辨识生态基流价值变化规律,以沙颍河上游干流告成段、化行段、黄桥段2008年~2021年降水、蒸发、流量、人均用水量、人均GDP、水质达标率数据,建立影响生态基流因子体系,根据变异系数法和2021年生态基流价值,研究河段生态基流价值年际变化。研究表明:告成段生态基流价值在0.483亿~4.726亿元波动、化行段在10.106亿~79.954亿元变化、黄桥段变化范围是7.201亿~46.431亿元;告成段、黄桥段水质因子所占权重最大,其次是流量、降水量因子;化行段因水质较优,流量因子所占权重最大,水质、降水量因子次之;经济、蒸发量、用水量因子在各河段的权重均较小,对生态基流价值的影响不大。河段年均流量与降水量排序为黄桥段>化行段>告成段,但生态基流价值排序为化行段>黄桥段>告成段,说明生态基流价值首先取决于水质,其次是流量与降水量。

AWTV和高斯注意力引导的LDCT图像去噪网络

低剂量CT(low-dose CT,LDCT)图像的去噪任务是一个高度复杂且不确定的逆问题。现有的基于CNN的方法虽然有效,但提升空间有限且计算成本高。相比之下,将图像先验知识与模型相结合来辅助图像去噪是一种更有效的方法。提出了一种名为AWTV_GANet的LDCT图像去噪框架。该框架利用自适应加权总变分(adaptive weighted total variation,AWTV)展开和高斯注意力引导的方法,通过端到端的CNN模型,将噪声优化模型、边缘检测模型和图像重建模型集成在一起。实验证明,AWTV_GANet能够准确地去除伪影噪声,并恢复出更精细的结构细节,与其他方法相比具有优异的性能。

基于动态优化周期的风光氢储耦合系统改进能量管理策略

电/氢混合储能对离网风光发电系统的功率调节能力起到不可忽视的作用,但未充分考虑能量管理的综合性能。针对上述问题,提出了一种基于动态优化周期的改进能量管理策略。首先,以系统运行成本最小为目标进行日前优化。然后,在日内滚动优化的过程中自适应调节权重因子,合理协调短期功率平抑和长期状态优化,并对滚动优化周期进行动态调节,在减少冗余调节的同时,提升控制器的实时响应能力。最后,在实时校正层分别使用逐次变分模态分解和双层模糊控制对混合储能功率进行初次分配和二次分配,充分利用混合储能的运行特性并提升系统鲁棒性。算例分析表明,与传统策略相比,改进能量管理策略可使系统运行成本、能量失衡率和计算时间分别降低38.3%、63.1%和57.9%,提高了系统能量管理的经济性、可靠性和实时性。

加权特征参数信息重构方法及其在主轴承故障诊断中的应用

为解决航空发动机内滚动轴承微弱故障识别受到环境噪声干扰和重要信息易被忽略的问题,提出一种新的加权特征参数信息重构方法,并将其运用到航空发动机的主轴承故障检测中。该方法首先采用粒子群算法(Particle swarm optimization,PSO)优化变分模态分解(Variational mode decomposi-tion,VMD)中的参数,得到K0个模态分量;然后提出一种新的加权特征参数信息重构公式,将所有模态分量按照该公式进行加权重构,过滤噪声成分,并更大程度地保留有效信息;最后对重构信号进行包络分析提取出轴承故障特征信息。通过对航空发动机中介轴承试验故障数据进行分析,得到结论:该方法可降低噪声成分对整体信号的干扰,有效突显出故障特征信息,诊断强背景噪声强干扰工况下的轴承微弱故障,因此是一种有效的用于航空发动机主轴轴承故障特征提取与诊断的方法之一。经仿真信号计算,降噪后的信号峰值因子提升1.62 d B,有效增强了冲击性成分。

Natural variation in MORE GRAINS 1 regulates grain number and grain weight in rice

Grain yield is determined mainly by grain number and grain weight.In this study,we identified and characterized MORE GRAINS1(MOG1),a gene associated with grain number and grain weight in rice(Oryza sativa L.),through map-based cloning.Overexpression of MOG1 increased grain yield by 18.6%-22.3%under field conditions.We determined that MOG1,a bHLH transcription factor,interacts with OsbHLH107 and directly activates the expression of LONELY GUY(LOG),which encodes a cytokinin-activating enzyme and the cell expansion gene EXPANSIN-LIKE1(EXPLA1),positively regulating grain number per panicle and grain weight.Natural variations in the promoter and coding regions of MOG1 between Hap-LNW and Hap-HNW alleles resulted in changes in MOG1 expression level and transcriptional activation,leading to functional differences.Haplotype analysis revealed that Hap-HNW,which results in a greater number and heavier grains,has undergone strong selection but has been poorly utilized in modern lowland rice breeding.In summary,the MOG1-OsbHLH107 complex activates LOG and EXPLA1 expression to promote cell expansion and division of young panicles through the cytokinin pathway,thereby increasing grain number and grain weight.These findings suggest that Hap-HNW could be used in strategies to breed high-yielding temperate japonica lowland rice.

Weighted variation inequalities for differential operators and singular integrals in higher dimensions

We prove weighted q-variation inequalities with 2<q<∞for sharp truncations of singular integral operators in higher dimensions.The vector-valued extensions of these inequalities are also given.Parallel results are proven for differential operators.

Weighted Oscillation and Variation Inequalities for Singular Integrals and Commutators Satisfying Hrmander Type Conditions

This paper is devoted to investigating the weighted LP-mapping properties of oscillation and variation operators related to the families of singular integrals and their commutators in higher dimension. We establish the weighted type （p, p） estimates for 1 〈 p 〈 ∞ and the weighted weak type （1, 1） estimate for the oscillation and variation operators of singular integrals with kernels satisfying certain HSrmander type conditions, which contain the Riesz transforms, singular integrals with more general homogeneous kernels satisfying the Lipschitz conditions and the classical Dini＇s conditions as model examples. Meanwhile, we also obtain the weighted LP-boundeness for such operators associated to the family of commutators generated by the singular integrals above with BMO（Rd）-functions.

Compressive Sensing Reconstruction Based on Weighted Directional Total Variation

Directionality of image plays a very important role in human visual system and it is important prior information of image. In this paper we propose a weighted directional total variation model to reconstruct image from its finite number of noisy compressive samples. A novel self-adaption, texture preservation method is designed to select the weight. Inspired by majorization-minimization scheme, we develop an efficient algorithm to seek the optimal solution of the proposed model by minimizing a sequence of quadratic surrogate penalties. The numerical examples are performed to compare its performance with four state-of-the-art algorithms. Experimental results clearly show that our method has better reconstruction accuracy on texture images than the existing scheme.

Asymptotic Tail Probability of Randomly Weighted Sums of Dependent Random Variables with Dominated Variation

This paper investigates the asymptotic behavior of tail probability of randomly weighted sums of dependent and real-valued random variables with dominated variation, where the weights form another sequence of nonnegative random variables. The result we obtain extends the corresponding result of Wang and Tang.

Medical Diagnosis System Based on Fast-weights Scheme

Clinical examination data often have the features of carrying vague information,missing data and incomplete examination records,which lead to higher probabilities of misdiagnosis.A variational recursive-discriminant joint model with fast weights(FWs)scheme is proposed.MIMIC-III data sets are trained and tested,and the results are used to diagnosing.Variational recurrent neural network(VRNN)with FWs can better obtain the temporal features with partly missing data,and discriminant neural network(DNN)is for decision.Moreover,layer regularization(LN)avoids the overflow of loss function and stabilize the dynamic parameters of each layer.For the simulations,10 laboratory tests were selected to predict 10 diseases,1600 samples and 400 samples were used for training and testing,respectively.The test accuracy of disease diagnosis without FWs is 72.55%,and that with FWs is 85.80%.Simulations reveal that the FWs mechanism can effectively optimize the system model,abstracting the features for diagnose,and significantly improve the accuracy of decision-making.

Variation operators for singular integrals and their commutators on weighted Morrey spaces and Sobolev spaces

In this paper,we investigate the boundedness and compactness for variation operators of CalderónZygmund singular integrals and their commutators on weighted Morrey spaces and Sobolev spaces.To be precise,letρ>2 and K be a standard Calderón-Zygmund kernel.Denote by V_(ρ)(T_(K))and V_(ρ)(T_(K,b)^(m))(m≥1)theρ-variation operators of Calderón-Zygmund singular integrals and their m-th iterated commutators,respectively.By assuming that V_(ρ)(T_(K))satisfies an a priori estimate,i.e.,the map V_(ρ)(T_(K)):L^(p0)(R^(n))→L^(p0)(R^(n))is bounded for some p0∈(1,∞),the bounds for V_(ρ)(T_(K))and V_(ρ)(T_(K,b)^(m))on weighted Morrey spaces and Sobolev spaces are established.Meanwhile,the compactness properties of V_(ρ)(T_(K,b)^(m))on weighted Lebesgue and Morrey spaces are also discussed.As applications,the corresponding results for the Hilbert transform,the Hermite Riesz transform,Riesz transforms and rough singular integrals as well as their commutators on the above function spaces are presented.

基于“潜力⁃弹性⁃稳定性”模型的温州市生态韧性时空变化及影响因素研究

城市生态韧性为城市应对长期发展积累的内在压力,以及外界不确定性风险的冲击提供了新思路,对城市的可持续发展具有重要意义。基于城市生态学视角,从生态韧性的抵御力、恢复力及适应力三个方面特性,构建基于“潜力⁃弹性⁃稳定性”的生态韧性评价模型,分析了1990—2020年温州市生态韧性时空变化特征,并运用时空地理加权回归模型(GTWR),探究了生态韧性影响因素的时空异质性。结果表明:(1)1990—2020年,温州城市生态韧性指数总体呈现先上升后下降的趋势,潜力、弹性、稳定性呈现出相似的变化趋势,研究后期稳定性的提升使生态韧性的下降得到短暂缓解。(2)温州市东部沿海地区生态韧性较差,西部与北部山地生态韧性较好;低韧性水平区呈现出区域中心韧性水平降低,并且向外围扩张的趋势。(3)温州市城市生态韧性影响因素之间存在显著的时空差异,空间上也存在波动方向与强度的差异,这种差异性集中分布于城市边缘县(区)。研究以期为温州市及沿海同等级城市,提升城市生态韧性、促进区域可持续发展决策提供参考。