A Study of Bilinear Models in Voice Conversion

This paper presents a voice conversion technique based on bilinear models and introduces the concept of contextual modeling. The bilinear approach reformulates the spectral envelope representation from line spectral frequencies feature to a two-factor parameterization corresponding to speaker identity and phonetic information, the so-called style and content factors. This decomposition offers a flexible representation suitable for voice conversion and facilitates the use of efficient training algorithms based on singular value decomposition. In a contextual approach (bilinear) models are trained on subsets of the training data selected on the fly at conversion time depending on the characteristics of the feature vector to be converted. The performance of bilinear models and context modeling is evaluated in objective and perceptual tests by comparison with the popular GMM-based voice conversion method for several sizes and different types of training data.

Direct scaling of residual displacements for bilinear and pinching oscillators

The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displacements plays an important role in ensuring cost-feasible or cost-effective repairs in a damaged structure after the event.An attempt is made in this study to obtain statistical estimates of constant-ductility residual displacement spectra for bilinear and pinching oscillators with 5%initial damping,directly in terms of easily available seismological,site,and model parameters.None of the available models for the bilinear and pinching oscillators are useful when design spectra for a seismic hazard at a site are not available.The statistical estimates of a residual displacement spectrum are proposed in terms of earthquake magnitude,epicentral distance,site geology parameter,and three model parameters for a given set of ductility demand and a hysteretic energy capacity coefficient in the case of bilinear and pinching models,as well as for a given set of pinching parameters for displacement and strength at the breakpoint in the case of pinching model alone.The proposed scaling model is applicable to horizontal ground motions in the western U.S.for earthquake magnitudes less than 7 or epicentral distances greater than 20 km.

Tail dependence of random variables from ARCH and heavy-tailed bilinear models

Discussed in this paper is the dependent structure in the tails of distributions of random variables from some heavy-tailed stationary nonlinear time series. One class of models discussed is the first-order autoregressive conditional heteroscedastic (ARCH) process introduced by Engle (1982). The other class is the simple first-order bilinear models driven by heavy-tailed innovations. We give some explicit formulas for the asymptotic values of conditional probabilities used for measuring the tail dependence between two random variables from these models. Our results have significant meanings in finance.

Stationary solution and parametric estimation for Bilinear model driven by ARCH noises

Bilinear model driven by ARCH (1) noises is proposed. Existence, uniqueness and form of sta-tionary solution to this new model are presented. Maximum likelihood estimation of the model is discussedand some simulation results are given to evaluate our algorithm.

State Estimation Moving Window Gradient Iterative Algorithm for Bilinear Systems Using the Continuous Mixed p-norm Technique

This paper studies the parameter estimation problems of the nonlinear systems described by the bilinear state space models in the presence of disturbances.A bilinear state observer is designed for deriving identification algorithms to estimate the state variables using the input-output data.Based on the bilinear state observer,a novel gradient iterative algorithm is derived for estimating the parameters of the bilinear systems by means of the continuous mixed p-norm cost function.The gain at each iterative step adapts to the data quality so that the algorithm has good robustness to the noise disturbance.Furthermore,to improve the performance of the proposed algorithm,a dynamicmoving window is designed which can update the dynamical data by removing the oldest data and adding the newestmeasurement data.A numerical example of identification of bilinear systems is presented to validate the theoretical analysis.

基于粒子群算法的钢丝网垫隔振器参数识别

目的 证明粒子群优化算法对钢丝网垫隔振器参数识别的有效性和准确性。探究不同的加载条件对钢丝网垫元件力学性能的影响。方法 对钢丝网垫元件进行正弦加载试验,获取试验响应数据。以双折线模型对钢丝网垫的力学性能进行描述,建立隔振器的参数识别方程,应用粒子群算法和试验响应数据识别出模型参数,并研究不同加载条件下识别参数的变化规律。结果 用识别出的参数计算绘制的迟滞回线和试验结果吻合较好。改变激励幅值和频率,钢丝网垫的一次刚度、三次刚度、滑移刚度、等效阻尼均发生规律性变化,而改变钢丝网垫所受静载,曲线变化极为微小。结论 研究证明了粒子群优化算法对钢丝网垫隔振器参数识别的有效性和准确性,是一种有工程应用价值的参数识别方法。

基于稳态响应规律的双线性滞回模型等效参数研究

为了研究等效线性化方法的位移估算精度,以双线性滞回模型为分析模型,分析了非线性单自由度体系的自由振动过程,指出采用割线刚度法(R-H法)计算的等效参数与实际结果偏差较大,进而提出了一种简谐力作用下的等效参数计算方法。考虑了简谐激励的激励周期以及结构振动的位移峰值对计算结果的影响,通过数值分析对不同参数对应下的非线性体系进行等效线性化分析,验证了所提出的等效参数计算方法的有效性与准确性。结果表明,采用R-H法计算的等效刚度偏大,而改进方法能够合理估算非线性时程位移结果,其计算精度优于R-H法。

时滞戒毒模型的稳定性和Hopf分岔

研究了一类具有双线性接触率的时滞SLHMTQ戒毒模型.以吸毒者毒瘾复发的时滞为分岔参数,利用特征值法探究了模型的局部渐近稳定性和局部Hopf分岔存在性,推导出模型产生局部Hopf分岔的时滞临界值,并利用中心流形定理讨论了分岔周期解的性质.

CrMoV钢近门槛值区疲劳裂纹扩展评价模型准确性分析

近门槛值区的疲劳裂纹扩展行为及疲劳门槛值的确定对于工程材料与结构的疲劳性能和损伤容限设计具有重要意义。采用25Cr2Ni2MoV钢的疲劳裂纹扩展数据,运用Paris模型、NASGRO模型、Zhu-Xuan模型分别预测疲劳裂纹扩展门槛值,比较各模型的预测误差;进一步将Zhu-Xuan模型与转折点预测模型结合而建立的双线性评价模型,与ASME规范和BS 7910标准中的评价模型,开展相对误差和准确度的比较。结果表明,Zhu-Xuan模型误差在10%以内,准确度最高;双线性评价模型预测结果与试验数据具有较好的一致性、更高的准确度和稳定性,其精度提升程度最高可达28.6%。得出Zhu-Xuan模型及双线性评价模型对CrMoV钢材料的门槛值预测及寿命精准评定具有较好的适用性的结论。

试样厚度对小冲杆试验力与材料强度相关性的影响

为了研究试样厚度对小冲杆试验力与材料强度相关性的影响,针对不同厚度(0.1~0.5 mm)的小冲杆试样,使用无屈服平台的虚拟材料进行了有限元模拟。通过提取并分析有限元模拟结果中固定挠度下的小冲杆试验力,证明了小冲杆试验力与材料屈服强度和抗拉强度的双线性关系,且厚度的变化不会影响该相关关系的皮尔逊相关系数。随机生成了屈强比在0.55~0.9之间,屈服强度在200~1000 MPa之间的100种虚拟材料,并通过有限元模拟获得了大量数据,进而采用退火粒子群算法得出了固定挠度下小冲杆试验力和材料强度的关联系数。采用4种真实材料验证了小冲杆试验力与材料强度呈双线性关系的结论。

基于内聚力模型数值算法的无砟道床变形与损伤分析

针对高速铁路无砟道床层间黏结数值模拟问题,推导混合断裂模式双线性内聚力模型,提出有限元分析框架下的双线性内聚力模型(CZM)数值算法,通过与有限元软件计算结果对比,验证算法的正确性。基于所提出算法,以内聚力单元模拟层间界面,建立CRTSⅢ型板式无砟道床有限元模型,分析温度梯度荷载作用下结构变形与层间损伤规律。结果表明:所提出CZM数值算法与有限元软件计算结果一致,可以反映内聚力单元在受拉、受剪、受拉剪模式下的力学与损伤特性;在-50~100℃/m温度梯度范围内,正温度梯度荷载作用下轨道板垂向位移可达0509 mm,负温度梯度荷载作用下则可达0409 mm;轨道板与自密实混凝土层层间损伤受正温度梯度影响大,层间损伤萌生于板角并向板中发展,温度梯度为972℃/m时层间黏结局部失效。

面向复杂场景的车辆动态称重方法

在动态称重系统的实际应用中,车辆重量的测量结果往往受到多种外部环境因素的显著影响,如车型差异、胎压变化和车速波动等,这些因素导致测量结果的波动较大,影响了称重的准确性。为了应对这一挑战,本文提出了一种创新的基于因子分析模型的车辆动态称重方法,旨在有效地分离和减少这些干扰因素对称重结果的影响。首先,对采集到的特征矩阵运用双线性模型进行深入的因子分析。通过这种方法,能够有效地分离出车辆外部因子,从而提取出与车辆本身重量更为紧密相关的、近似车辆无关的车重特征。随后,利用这些经过因子分离处理后的车重信号进行车辆重量的估算。通过此方法,能够更准确地反映车辆的真实重量,同时减少了由于外部环境因素引起的误差。实验结果表明,本文所提出的方法在动态称重中表现出色。它不仅显著改善了称重的稳定性,而且成功地将称重误差控制在了5%以下的较低水平,这充分验证了该方法的有效性和实用性。

一种适用于车载自组织网络的无证书混合签密方案

为提高车载自组织网络中消息认证的机密性,提出了一种可证安全性的高效无证书混合签密方案。基于车载自组织网络系统模型,在车辆进行注册后引入假名自生成算法,并在签密算法中采用混合签密计算方式。理论证明与试验验证结果表明,与现有无证书签密方案相比,该方案在保护车辆隐私信息的同时,降低了可信中心和路侧单元的计算量,计算开销与通信开销保持较低水平,最后,在随机预言模型中证明了该方案的不可伪造性和机密性,并且能够抵御各类攻击。

长周期地震动作用下某EPR核电站安全壳的隔震性能分析

核电站安全壳是切实有效保证核电站安全的必备设施。研究长周期地震动作用下的安全壳隔震性能,对安全壳具有十分重要的理论意义和工程应用价值。以某EPR核电站安全壳为研究模型,考虑了该安全壳自重和预应力系统,采用软件ANSYS建立复杂的三维数值仿真模型,探讨长周期地震动作用下安全壳的变形、加速度、基底剪力和预应力筋的平均应力,证实在长周期地震动作用下,该安全壳受力性能良好,并在控制范围内。基于此,引入层叠橡胶隔震器和软钢隔震器并联的新型隔震装置,进而研究长周期地震动作用下安全壳的隔震性能。分析结果表明:由于地震动的特性(例如,随机性、不确定性、空间相关性等),核电站安全壳设计必须从多方面重视长周期地震动。短周期地震动作用下新型隔震装置是有效的,长周期地震动作用下隔震失效。研究结果为核电站安全壳隔震设计提供技术指导。

ARMA模型与bilinear模型的比较

文章从参数估计和数据拟合的视角出发，对时间序列中两个经典的模型-ARMA模型和bilinear模型的特性进行比较，比较之后发现：对于线性结构的数据，ARMA模型与bilinear模型拟合准确度相近，而对于具有非线性结构的数据，bilinear模型的拟合准确度明显高于ARMA模型。而且随着非线性部分在数据中占比的提高，bilinear模型相对于ARMA模型拟合的优越程度有所增加。

分离式减震榫的阻尼力模型研究-基于Ramberg-Osgood模型

如何更好地模拟分离式减震榫在地震过程中的滞回性能,是分离式减震榫减震设计中的重要组成部分。针对从材料层次描述分离式减震榫在往复荷载作用下力学性能的理论研究相对不足的问题,提出一种基于Ramberg-Osgood模型推导分离式减震榫骨架曲线的计算方法,并基于该方法提出一种适用于工程计算的双线性本构的简化算法。通过ABAQUS有限元软件对比Ramberg-Osgood模型,Chaboche本构和理想弹塑性本构下分离式减震榫骨架曲线的差异,并以一座通用的两跨32 m双线铁路预应力混凝土简支梁桥为背景,分析双线性本构简化算法在桥梁抗震设计中的适用性。结果表明:基于Ramberg-Osgood模型推导的分离式减震榫的骨架曲线,能够较好拟合Chaboche本构下的骨架曲线;在近断层脉冲地震动作用下通过双线性本构计算得到的支座位移峰值和墩底弯矩峰值,与Chaboche本构下得到的计算结果的平均误差分别为−2.67%和6.56%。该文提出的双线性模型的简化方法用于桥梁工程抗震设计是安全且合理的。

Fuzzy Varying Coefficient Bilinear Regression of Yield Series

We construct a fuzzy varying coefficient bilinear regression model to deal with the interval financial data and then adopt the least-squares method based on symmetric fuzzy number space. Firstly, we propose a varying coefficient model on the basis of the fuzzy bilinear regression model. Secondly, we develop the least-squares method according to the complete distance between fuzzy numbers to estimate the coefficients and test the adaptability of the proposed model by means of generalized likelihood ratio test with SSE composite index. Finally, mean square errors and mean absolutely errors are employed to evaluate and compare the fitting of fuzzy auto regression, fuzzy bilinear regression and fuzzy varying coefficient bilinear regression models, and also the forecasting of three models. Empirical analysis turns out that the proposed model has good fitting and forecasting accuracy with regard to other regression models for the capital market.

Provably Secure Short Proxy Signature Scheme from Bilinear Maps

An enhanced formal model of security for proxy signature schemes is presented and a provably secure short proxy signature scheme is proposed from bilinear maps. The proposed proxy signature scheme is based on two short secure signature schemes. One is used for delegating the signing rights and computing the standard signature; the other is used for computing proxy signature. Finally, a security proof of the proposed proxy signature scheme is showed by reducing tightly the security of the proposed proxy signature scheme to the security of the two basic signature schemes. The proposed proxy signature scheme has the shortest ordinary signatures and proxy signatures. Moreover, the proxy signature generation needs no pairing operation and verification needs just two pairing operation.

反馈非线性系统随机梯度辨识算法及其收敛性

反馈非线性受控自回归系统是由前向通道的受控自回归模型和反馈通道的静态非线性构成,这类系统经过参数化后得到双线性参数辨识模型.本文通过对辨识模型中双线性参数乘积项进行分解,基于梯度搜索原理,提出了反馈非线性系统的随机梯度辨识算法.为了改善随机梯度算法的收敛速度,引入遗忘因子,文章给出了遗忘因子随机梯度算法,利用随机过程理论,建立了随机梯度算法的参数估计收敛定理,证明了算法的收敛性.最后,通过数值仿真验证了算法的有效性.

传统木结构穿销式榫卯节点抗震性能分析

为研究不同穿销类型榫卯节点的抗震性能,考察了榫高、榫厚、柱径对节点力学性能的影响,采用有限元软件建模对榫卯节点进行拟静力分析,得到3类试件的滞回曲线、骨架曲线、耗能能力等抗震指标。结果表明:3类穿销榫卯的滞回曲线均呈现明显的Z型,捏缩效应较明显,3类试件的承载力相差不大;榫高、榫厚、柱径对榫卯节点的承载能力有显著影响,节点承载能力随榫厚、柱径增大而增大,随榫高的增大先增大后减小;根据穿销榫卯的骨架曲线建立了节点的弯矩-转角双折线模型,探讨了榫高、榫厚、柱径对模型参数的影响。在木结构设计中,应综合考虑榫卯尺寸变化对节点力学性能的影响。