基于DFT的频率敏感双分支Transformer多变量长时间序列预测方法

在进行多变量长时间序列预测时,仅利用时域分析通常无法充分捕捉长时间序列依赖,而这会导致信息利用率不足、预测精度不够高。因此,结合频域时域分析,提出一种基于离散傅里叶变换(DFT)的频率敏感双分支多变量长时间序列预测(FSDformer)方法。首先,通过DFT实现时间和频率的相互转换,从而将复杂的时间序列数据分解为结构简单的低频趋势项、中频季节项和高频余项3个分量;其次,采用双分支结构,针对中高频分量预测,应用Encoder-Decoder结构,设计了周期性增强注意力机制;针对低频趋势分量预测,采用多层感知机(MLP)结构;最后将中高频分量与低频分量预测结果相加,得到多变量长时间序列的最终预测结果。在2个数据集上把FSDformer与其他5个经典算法进行了对比分析,在Electricity数据集上,当历史序列长度为96,预测序列长度为336时,相较于Autoformer等对比算法,FSDformer的平均绝对误差(MAE)下降了11.5%~29.1%,均方误差(MSE)下降了20.9%~43.7%,达到了最优预测精度。实验结果表明,FSDformer能有效捕捉长时间序列的相关依赖,在提升预测精度和计算效率的同时,增强了模型预测的稳定性。

Local Extrema of Periodic Function’s Wavelet Transform

The theory of detecling ridges in the modulus of the continuous wavelet transform is presented as well as reconstructing signal by using information on ridges,To periodic signal we suppose Morlet wavelet as basic wavelet, and research the local extreme point and extrema of the wavelet transform on periodic function for the collection of signal＇ s instantaneous amplitude and period.

Geochronological and Geochemical Evidence for the Sedimentary Transformation from the Banxi Period to Nanhua Glacial Period

Objective There has been considerable debate about the definition of the lower boundary of Nanhua System by far.One definition is based on sedimentary sequence of different stages of basin evolution,focusing on whether deposits of the Banxi Period should be classified as Nanhua System.Another is the onset time of Nanhua glacial period.

ALMOST PERIODICITY AND EQUICONTINUITY OF THE TOPOLOGICAL TRANSFORMATION GROUP

In this paper, a characterization of almost periodicity of topological transformation groups on uniform spaces is given. By searching the appropriate base for uniform structure, it is shown that the topological transformation group is topologically equivalent to an isometric one if it is uniformly equicontinuous.

Period of Arnold transformation and its application in image scrambling

With the security problem of image information as the background, some more properties of the period of Arnold transformation of two-dimension were studied by means of introducing a integer sequence. Some new resuits are obtained. Two interesting conjectures on the period of Arnold transformation are given. When making digital images scrambling by Arnold transformation, it is important to know the period of the transformation for the image. As the application of the theory, a new method for computing the periods at last are proposed.

Novel mechanical behavior of periodic structure with the pattern transformation

Abstract In periodic cellular structures, novel pattern transformations are triggered by a reversible elastic instability under the axial compression. Based on the deformation-triggered new pattern, periodic cellular structures can achieve special mechanical properties. In this paper, the designed architecture materials which include elastomer matrixes containing empty holes or filled holes with hydrogel material are modeled and simulated to investigate the mechanical property of the periodic materials. By analyzing the relationship between nominal stress and nominal strain of periodic material, and the corresponding deformed patterns, the influence of geometry and shapes of the holes on the mechanical property of architecture material is studied in more details. We hope this study can provide future perspectives for the deformation-triggered periodic structures.

Detecting Periodicity Associated with the Alpha-Helix Structure Using Fourier Transform

Alpha helix is a common type of secondary structure in the protein structure that consists of repeating helical turns. Patterns in the protein sequences that cause this repetitive pattern in the structure have long been sought. We used the discrete Fourier transform (DFT) to detect the periodicity signals correlated to the helical structure. We studied the distribution of multiple properties along the protein sequence, and found a property that showed strong periodicity correlated with the helical structure. Using a short-time Fourier transform (STFT) method, we investigated the amplitude of the periodical signals at each amino acid position. The results show that residues in the helix structure tend to display higher amplitudes than residues outside of the helices. This tendency is dramatically strengthen when sequence profiles obtained from multiple alignment were used to detect the periodicity. A simple method that predicted helices based on the amplitude yielded overall true positive rate (TPR) of 63%, 49% sensitivity, 72% specificity, and 0.22 Matthews Correlation Coefficient (MCC). The performance seemed to depend on the length of helices that the proteins had.

THE WAVELET TRANSFORM OF PERIODIC FUNCTION AND NONSTATIONARY PERIODIC FUNCTION

Some properties of the wavelet transform of trigonometric Junction, periodic function and nonstationary periodic function have been investigated. The results show that the peak height and width in wavelet energy spectrum of a periodic function are in proportion to its period. At the same time, a new equation, which can truly reconstruct a trigonometric function with only one scale wavelet coefficient, is presented. The reconstructed wave shape of a periodic function with the equation is better than any term of its Fourier series. And the reconstructed wave shape of a class of nonstationary periodic function with this equation agrees well with the function.

Chandler Wobble Period and Q Derived by Wavelet Transform

We apply complex Morlet wavelet transform to three polar motion data series,and derive quasi-instantaneous periods of the Chandler and annual wobble by differencing the wavelettransform results versus the scale factor, and then find their zero points. The results show thatthe mean periods of the Chandler (annual) wobble are 430.71+-1.07 (365.24+-0.11) and 432.71+-0.42(365.23+-0.18) mean solar days for the data sets of 1900-2001 and 1940-2001, respectively. Themaximum relative variation of the quasi-instantaneous period to the mean of the Chandler wobble isless than 1.5% during 1900-2001 (3%-5% during 1920-1940), and that of the annual wobble is less than1.6% during 1900-2001. Quasi-instantaneous and mean values of Q are also derived by using theenergy density―period profile of the Chandler wobble. An asymptotic value of Q = 36.7 is obtainedby fitting polynomial of exponential of σ^(-2) to the relationship between Q and σ during1940-2001.

Quasi-Chun-Ching Shih's Fractional Fourier Transform with Periodicity of 2,3 and M

Based on Chun-Ching Shih’s idea,the basic transform was substituted and the quasi-Chun-Ching Shih’s fractional Fourier transform with periodicity of 2,3 and M was deduced.The two former transforms and the Chun-Ching Shih’s fractional Fourier transform were only the particular cases of quasi-Chun-Ching Shih’s fractional Fourier transform with periodicity of M.

Discrete Radon Transform and the Bounding Effective Properties of Periodical Isotropic Two-Phase Thermal Materials

This work is related to bounding the effective conductivity of an isotropic two-phase fibrous periodical composite.These well known bounds are classically obtained for any inclusion shape by the fourier method.So,they can be expressed only in the Fourier space.A real formulation of the solution of the periodical conductivity problem based on the discrete Radon transform has been recently proposed.The use of this framework leads us here to a simple and explicit real bounds for effective properties.The effect of the microstructure is hence more evidenced.It is also shown here that the obtained bounds coincide with the classical Hashin Shtrikmann bounds when the microstructure has some specific symmetry.

Cognitive Model of the Journalist on Journalism under Newspaper Industry Transformation Period

In this paper, we conduct research on cognitive model of the journalist on journalism under newspaper industry transformation period. “Journalism” is the logical starting point of theoretical journalism system that is the most abstract, general concept of journalism. Therefore, analyzing the connotation and the essence of “news activities” has special significance and value to the whole journalism, that especially theoretical journalism. All of these activities, together with the news dissemination activities as the core of the news activities, are the broad news activities. From the perspective of journalism, these activities constitute the main object of the study of journalism, news on different areas of activity, form different areas or different branches of journalism. For this, the paper proposes the cognitive model of the journalist on the journalism under newspaper industry transformation period that will promote the further development.

The change of the cationic peroxidase in the leaves at the fertile transformation period in Nongken 58s

Nongken 58s is a type of photoperiod sensitivegenie male sterile rice which gives rice to malesterility when illuminated time is longer than13.75 h/d.The photoperiod sensitive stagesare from the differentiation of primary branchprimordum(Ⅱ)in young ears to fullness ofcontents of the pollen(Ⅶ).The changes ofactivity and isoenzymes in cation peroxidase atph0toperiod sensitive stages and the relation-ship between this enzyme and feritility of rice

鲁东—黄海地块西部中强地震活动特征及周边地震对该地区的影响

鲁东—黄海地块西部为华北地块东侧的次级地块,其地震活动具有显著的周期特征,地块内部的中强地震活动特征和周边大震对该地区的影响对研究该地区地震活动状态有重要意义。采用小波分析方法定量计算了鲁东—黄海地块西部历史地震的活动周期,并结合中强地震活动的定性分析、时空演化、能量释放及周边大震等资料,探讨了该地区的地震活动特征。结果显示:(1)鲁东—黄海地块西部M5.0以上地震活动存在着60.6—78.6 a的长周期,该周期反映了地震活跃—平静的韵律特征,据此M≥5.0地震可划分为活跃时段Ⅰ(1844—1879年)、活跃时段Ⅱ(1905—1949年)和活跃时段Ⅲ(1974年至今)。1997年以来,该地区处于活跃时段末期的弱释放阶段;(2)在三个活跃时段,地震活动的主体地区不同,活跃时段Ⅰ,Ⅱ以海域地震活动为主,并且地震活动水平海域强、陆域弱。活跃时段Ⅲ陆域、海域均有M≥6.0地震活动;(3) 1815年以来,鲁东—黄海地块西部M≥5.0地震与华北M≥6.0地震活动大致同步,当鲁东—黄海地块西部中强地震恰好处于较强活跃时段时,华北地块M6.0地震显著平静后,M≥6.0地震先从鲁东—黄海地块西部开始活动,然后向华北地块中西部地区活动;(4)当太平洋板块西侧的俯冲带上M_(W)≥5.0中深源地震活跃,并发生M_(W)≥7.0地震时,鲁东—黄海地块西部易于发生M_(S)≥6.0地震,这可能是太平洋板块西侧深部俯冲构造动力作用增强导致的结果。

基于希尔伯特-黄变换与小波分析的降雨序列多时间尺度研究

[目的]对比分析不同方法在多尺度周期计算性能方面的差异,为区域水文周期分析方法的选择提供更多参考。[方法]利用2组已知周期和趋势特征的人工序列,对基于多元经验模态分解(Multivariate Empirical Mode Decomposition,MEMD)改进的希尔伯特—黄变换(Hilbert-Huang Transform,HHT)与小波分析在多尺度周期计算性能差异上进行了测试、对比与分析;并在此基础上,使用改进的HHT(后称HHT)进一步分析了毛乌素沙地11个站点39年降雨序列的多时间尺度特征。[结果]对于人工序列,小波分析(对称延拓)结果偏大,与预设周期存在显著差异(Sig.=0.003<0.05);而HHT和小波分析(周期延拓)的周期结果与预设周期没有显著差异,且HHT精度(Sig.=0.142>0.05)要略高于周期延拓小波(Sig.=0.109>0.05)。对于实测降雨序列,HHT显示毛乌素沙地的降雨主周期存在明显区域差异:腹地站点降雨主周期为5.5 a,而边缘站点为2.7~3.3 a;分解后的残差分量表明了沙地降雨在时间上呈上升趋势,而空间上呈现由东到西逐渐减少的分布状态。[结论]HHT因其自适应性,无需考虑众多参数的选取,在保持精度的同时可以提取更多水文信息,在区域降雨序列多尺度分析上更具优势,因此具有重要的实际应用价值。

围绝经期卵巢型子宫内膜异位症恶变风险预测模型的建立及评估

目的构建围绝经期卵巢型子宫内膜异位症(OE)恶变风险的预测模型。方法回顾性分析2013年1月至2021年12月就诊于郑州大学第三附属医院、河南省人民医院、河南省肿瘤医院,处于围绝经期并经病理确诊的236例OE患者及41例子宫内膜异位症相关性卵巢癌(EAOC)患者的临床资料。采用多因素Logistic回归分析确定围绝经期OE患者发生恶变的危险因素,运用R软件绘制列线图模型并进行模型的评估。结果建模集OE组与建模集EAOC组的绝经状态、既往巧囊剥除史、合并自身癌症、直系亲属癌症、痛经时间5年及以上、进行性痛经、月经紊乱、术前疾病管理3年以上、不孕、包块压痛触痛、OE分型、重型内异症、超声下病变侧别、超声下包块呈现血流信号、磁共振成像下乳头状结构、磁共振成像下结合带完整的分布,以及初次性生活年龄、孕次、初次妊娠年龄、初次分娩年龄,经比较差异均有统计学意义(χ2值分别为17.527、16.255、1.634、7.609、20.822、15.313、5.140、4.751、13.303、5.264、8.448、8.920、5.248、8.385、7.029、4.223,t值分别为2.228、2.052、3.863、3.046,P<0.1)。验证集OE组与验证集EAOC组的绝经状态、既往巧囊剥除史、月经量多、伴发痛经、痛经时间5年及以上、进行性痛经、术前疾病管理3年以上、不孕、包块固定不动、OE分型、重型内异症、超声下包块呈现血流信号、磁共振成像下囊壁增厚、磁共振成像下乳头状结构的分布比较差异均有统计学意义(χ2值分别为3.558、20.707、5.004、5.920、10.616、2.325、6.727、4.964、4.234、5.384、1.251、2.325、7.892、6.950,P<0.1)。多因素Logistic回归分析结果显示:绝经状态(OR=5.007,95%CI:1.363~18.394)、进行性痛经(OR=3.583,95%CI:0.909~14.122)、不孕(OR=22.489,95%CI:3.552~42.382)、重型内异症(OR=3.800,95%CI:0.894~16.147)、超声下包块呈现血流信号(OR=3.431,95%CI:1.044~11.280)均是围绝经期OE恶变发生的独立危险因素(P<0.1)。ROC曲线分析结果显示,建模集曲线下面积(AUC)为0.848(95%CI:0.769~0.928),验证集AUC为0.880(95%CI:0.725~0.941)。建模集和验证集的校正曲线与理想曲线均拟合良好,Hosmer-Lemeshow拟合优度检验结果分别为χ2=3.691,P=0.884;χ2=4.166,P=0.842。结论绝经状态、进行性痛经、不孕、重型内异症、超声下包块呈现血流信号均是围绝经期OE恶变发生的独立危险因素,基于上述指标建立的列线图模型具有良好的区分度,预测值与实际值之间具有较好的准确性和一致性,对高危人群有较高地筛选能力。

行为分阶段转变理论的个案管理模式在慢性阻塞性肺疾病稳定期患者中的应用

目的探讨行为分阶段转变理论的个案管理模式在慢性阻塞性肺疾病(以下简称“慢阻肺”)稳定期患者中的应用效果。方法纳入南京市第一医院2021年6月至2022年6月门诊访视的112例慢阻肺稳定期患者进行前瞻性研究,通过随机数字表法将其分为对照组和观察组,各56例。对照组给予个案管理模式干预,观察组给予行为分阶段转变理论的个案管理模式。两组均连续干预6个月。比较干预前、干预6个月后呼吸功能[圣乔治呼吸问卷(SGRQ)、改良版英国医院研究委员会呼吸困难量表(m MRC)]、自我管理能力[健康行为能力自评量表(SRAHP)]。结果干预后,两组SGRQ、m MRC评分均低于干预前,且观察组低于对照组,差异有统计学意义(P<0.05)。干预后,两组SRAHP评分高于干预前,且观察组高于对照组,差异有统计学意义(P<0.05)。结论行为分阶段转变理论的个案管理模式提高慢阻肺稳定期患者的自我管理能力,改善呼吸功能,具有较好应用效果。

叶利钦时期俄罗斯经济体制转型评析

叶利钦执政后,俄罗斯推行被称为“休克疗法”的激进改革,其基本内容一般归结为自由化、稳定化与私有化。实行“休克疗法”有着特殊的历史、政治和经济原因。经济体制转型并没有使俄罗斯摆脱经济困境,反而给人民生活带来了很大困难。出现严重转型危机的原因十分复杂,不能完全归结为推行“休克疗法”。严重转型危机是苏联经济的惯性影响、外部因素的影响以及主观上的失误和错误等一系列因素共同导致的。总的来看,就大方向而言,叶利钦时期的经济体制转型是符合社会历史发展潮流的。

“百年未有之大变局”与“动荡变革期”的学理阐释

战略问题事关党和国家的前途命运,准确的战略判断有助于推动党和国家各项事业的发展。中国共产党向来重视战略认知和战略判断,认为当前百年未有之大变局加速演进,世界进入新的动荡变革期,我国发展进入战略机遇和风险挑战并存、不确定难预料因素增多的时期。这是对当下国际形势整体特征和性质的战略论断,也指出中国发展面临新的战略机遇与风险挑战。对相关战略论断进行学理化研究,有助于更好地把握战略机遇和应对各种风险挑战,推动中国和世界共同发展,为解决全人类共同面临的问题与构建人类命运共同体提供更多更好的中国智慧、中国方案和中国力量。