房地产股价波动对高技术板块的溢出效应研究——基于DGC-t-MSV模型

过度的金融资产投资可能导致房地产股价泡沫,并且通过风险溢出渠道给高技术板块带来价格冲击。研究聚焦于房地产行业和高技术产业的股票价格指数,结合MODWT分解和DGC-t-MSV模型进行实证分析,结果表明:其一,“房地产-高技术”的股票价格动态相关,房地产行业价格波动的传导作用更加强烈,对高技术板块具有明显的溢出效应;其二,实施限制性政策后房地产行业的挤出效应降低,高技术及其分类产业的创新投入受到的限制逐渐减弱;其三,短、中期频繁交易是导致房地产溢价的主要原因,需要警惕高技术板块面临的溢出风险。积极引导高技术板块的价值投资,合理配置技术要素,能够有效促进高技术产业的高质量、高水平发展。

基于T态模型的课程考核方案改进与实践

课程考核方案的T态模型从两个维度提升考核设计:横向的要素设计维度,即学习者知识、能力及素质在考核中均有衡量;纵向思考深度,逻辑的价值递进性。管理沟通课程考核方案的改进以T态模型为框架,旨在提升课程的“高阶性”与“挑战度”。通过建立“目标导向”试题库,构建网络教学资源库、建立阶段性考核方案、构建线上线下结合的立体考核模式来进行考核的改进。具体实施的过程中,课前布置、课中投票问答、课后测验和期末测试均围绕增强应用性、灵活性的原则,构建丰富性、反思性强的考核体系。实施效果表明新的考核方案能够提高学习者参与度和学习积极性,有助于培养学习者终身学习的习惯、提升团队协作与解决复杂问题的能力,形成了横纵交织的课程考核结构,横联纵进效应的高品质、目标导向的整体考核。

基于InVEST模型的大兴安岭天保工程区碳储量时空变化研究

为给大兴安岭天保工程区生态系统保护和土地利用规划提供科学依据,以大兴安岭天保工程区为研究区,基于研究区2000—2020年土地利用数据和各地类碳密度数据,运用InVEST模型碳储量模块对大兴安岭天保工程区2000—2020年生态系统的碳储量进行估算,并通过土地利用转移矩阵分析土地利用类型之间的相互转化对碳储量的影响。结果显示:(1)研究区2000、2005、2010、2015、2020年碳储量分别为569.87×10^(7)、573.22×10^(7)、573.69×10^(7)、572.42×10^(7)、573.14×10^(7) t,呈增加趋势,累计增加3.27×10^(7) t;(2)碳储量较高的地区主要分布在北部和中部,较低的区域主要分布西部、南部、东南角和东部小区域;(3)林地是研究区最重要的碳库,其碳储量占研究区固碳总量的93.31%,林地和耕地面积的增加是大兴安岭天保工程区碳储量增加的主要原因。研究结果表明:天保工程促使大兴安岭林地面积保持稳定并且呈现出一定增长趋势,提高了大兴安岭的整体固碳能力。在未来,大兴安岭应当继续实施和巩固天然林保护工程,继续坚持退耕还林还草政策,通过合理的行政规划,调控草地和耕地向建设性用地转换;此外,通过人工种植、草畜平衡的政策,围栏封育和优化种苗的方式来缓解草地退化,修复草地生态系统;而耕地则通过间作套作、改良品种、合理使用肥料等方法提高产量。

基于量子衍生涡流算法和T⁃S模糊推理模型的储层岩性识别

鉴于梯度下降法易陷入局部极值、普通群智能优化算法易早熟收敛,提出一种基于量子衍生涡流算法(Quantum Vortex Search Algorithm,QVSA)和T⁃S模糊推理模型的岩性识别方法,QVSA具有操作简单、收敛速度快、寻优能力强等优点,有助于T⁃S模糊推理模型获得最优参数配置,从而实现储层岩性的准确识别。首先利用具有全局搜索能力的QVSA优化T⁃S模糊推理模型的各种参数;然后利用主成分分析方法降低获取的地震属性维度;再利用优化的T⁃S模糊推理模型识别储层岩性。实验结果表明,利用反映储层特征的8个地震属性识别储层岩性时,所提方法的识别正确率达到92%,比普通BP网络方法高5.1%,同时查准率、查全率、F1分数等指标也较BP网络方法提升明显。

基于改进MobileNet V3的矿物智能识别模型

针对当前矿物识别领域存在的精度不佳、适应性差、携带不便等问题,提出了一种基于改进MobileNet V3的矿物智能识别模型(CA-MobileNet V3)。为获得研究所需的有效数据集,通过由mindat. org网站和自行拍摄方式获取的矿物图像创建了一个包含19种矿物的数据集,对其进行数据增强处理,并按照8:1:1的比例划分为训练集、验证集和测试集。为提升模型对图像信息的特征提取能力,引入协调注意力机制,用以替代轻量型MobileNet V3模型的原始SE注意力机制,以提高矿物识别准确率。最后,采用迁移学习方法预训练CA-MobileNet V3模型,以加速模型收敛、提高泛化能力、避免过拟合。在训练过程中,将CA-MobileNet V3与mobilenet v3、MobileNet V3、ShuffleNet V2、Efficient Net V2等模型进行了性能比较。结果表明:各迁移模型均展现出显著的收敛速度优势,而CA-MobileNet V3矿物智能识别模型的Top1-准确率、Top2-准确率、f_1-score值分别达到93.90%、98.58%和93.89%,在所有模型中效果最佳,且模型大小仅为4.61 MB,属于轻量化模型。为验证模型有效性,t-SNE可视化分析被用于不同模型的识别效果比较,进一步印证了CA-MobileNet V3模型的优越性。

LOCAL INFLUENCE ASSESSMENT IN A MULTIVARIATE t-MODEL WITH RAO'S SIMPLE STRUCTURE

The local influence analysis is an important problem in statistical inference and some models have been discussed in many literatures This paper deals with the problem of assessing local influences in a multivariate t-model with Rao's simple struc-ture(RSS). Based on Cook's likelihood displacement, the effects of some minor perturbation on the statistical inference is assessed. As an application, a common covariance-weighted perturbation is thoroughly discussed.

S-T-S混合式循环互助教学模式用于少学时“化工原理”课程

“化工原理”课程是化工及相关专业的专业基础课程,相关专业的学时少,课程难,需重点解决的问题是“三多”“三不愿”“三不明”。针对痛点问题,提出了线上线下混合式循环互助的创新设计思路,包括:教师帮助学生自制课前、课中、课后习题,学生帮助教师反馈真实学习情况,学生帮助学生组团互助学习。问卷调查和评教结果显示,在一定程度上解决了“三多”“三不愿”的问题;通过建立“助教团队”反馈不同层次学生的学习情况,较好地解决了“三不明”的问题。学生的成绩与教改前相比有明显提高。

A unified approach to fuzzy modelling and robust synchronization of different hyperchaotic systems

In this paper, a Takagi Sugeno （T-S） fuzzy model-based method is proposed to deal with the problem of synchronization of two identical or different hyperchaotic systems. The T S fuzzy models with a small number of fuzzy IF-THEN rules are employed to represent many typical hyperchaotic systems exactly. The benefit of employing the T-S fuzzy models lies in mathematical simplicity of analysis. Based on the T-S fuzzy hyperchaotic models, two fuzzy controllers arc designed via parallel distributed compensation （PDC） and exact linearization （EL） techniques to synchronize two identical hyperchaotic systems with uncertain parameters and two different hyperchaotic systems, respectively. The sufficient conditions for the robust synchronization of two identical hyperchaotic systems with uncertain parameters and the asymptotic synchronization of two different hyperchaotic systems are derived by applying the Lyapunov stability theory. This method is a universal one of synchronizing two identical or different hyperchaotic systems. Numerical examples are given to demonstrate the validity of the proposed fuzzy model and hyperchaotic synchronization scheme.

A hydrocarbon enrichment model and prediction of favorable accumulation areas in complicated superimposed basins in China

The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydrocarbon generation and expulsion from source rocks, multi-cycle hydrocarbon enrichment and accumulation, and multi-phase reservoir adjustment and reconstruction. The enrichment, accumulation and distribution of hydrocarbon is mainly controlled by the source rock kitchen, paleo- anticline, regional cap rock and intensity of tectonic movement. In this paper, the T-BCMS model has been developed to predict favorable areas of hydrocarbon accumulation in complicated superimposed basins according to time and spatial relationships among five key factors. The five factors include unconformity surface representing tectonic balancing （B）, regional cap rock representing hydrocarbon protection （C）, paleo-anticline representing hydrocarbon migration and accumulation （M）, source rock kitchen representing hydrocarbon generation and expulsion （S） and geological time （T）. There are three necessary conditions to form favorable areas of hydrocarbon accumulation. First, four key factors BCMS should be strictly in the order of BCMS from top to bottom. Second, superimposition of four key factors BCMS in the same area is the most favorable for hydrocarbon accumulation. Third, vertically ordered combination and superimposition in the same area of BCMS should occur at the same geological time. The model has been used to predict the most favorable exploration areas in Ordovician in the Tarim Basin in the main hydrocarbon accumulation periods. The result shows that 95% of the discovered Ordovician hydrocarbon reservoirs are located in the predicted areas, which indicates the feasibility and reliability of the key factor matching T-BCMS model for hydrocarbon accumulation and enrichment.

Application of the Improved Generalized Autoregressive Conditional Heteroskedast Model Based on the Autoregressive Integrated Moving Average Model in Data Analysis

This study firstly improved the Generalized Autoregressive Conditional Heteroskedast model for the issue that financial product sales data have singular information when applying this model, and the improved outlier detection method was used to detect the location of outliers, which were processed by the iterative method. Secondly, in order to describe the peak and fat tail of the financial time series, as well as the leverage effect, this work used the skewed-t Asymmetric Power Autoregressive Conditional Heteroskedasticity model based on the Autoregressive Integrated Moving Average Model to analyze the sales data. Empirical analysis showed that the model considering the skewed distribution is effective.

Predictive functional control based on fuzzy T-S model for HVAC systems temperature control

In heating, ventilating and air-conditioning （HVAC） systems, there exist severe nonlinearity, time-varying nature, disturbances and uncertainties. A new predictive functional control based on Takagi-Sugeno （T-S） fuzzy model was proposed to control HVAC systems. The T-S fuzzy model of stabilized controlled process was obtained using the least squares method, then on the basis of global linear predictive model from T-S fuzzy model, the process was controlled by the predictive functional controller. Especially the feedback regulation part was developed to compensate uncertainties of fuzzy predictive model. Finally simulation test results in HVAC systems control applications showed that the proposed fuzzy model predictive functional control improves tracking effect and robustness. Compared with the conventional PID controller, this control strategy has the advantages of less overshoot and shorter setting time, etc.

Controller Design for Electric Power Steering System Using T-S Fuzzy Model Approach

Pressure ripples in electric power steering （EPS） systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno （T-S） fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation （PDC） structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality （LMI） problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.

3-D hybrid LES-RANS model for simulation of open-channel T-diversion flows

The study of flow diversions in open channels plays an important practical role in the design and management of open-channel networks for irrigation or drainage. To accurately predict the mean flow and turbulence characteristics of open-channel dividing flows, a hybrid LES-RANS model, which combines the large eddy simulation （LES） model with the Reynolds-averaged Navier-Stokes （RANS） model, is proposed in the present study. The unsteady RANS model was used to simulate the upstream and downstream regions of a main channel, as well as the downstream region of a branch channel. The LES model was used to simulate the channel diversion region, where turbulent flow characteristics are complicated. Isotropic velocity fluctuations were added at the inflow interface of the LES region to trigger the generation of resolved turbulence. A method based on the virtual body force is proposed to impose Reynolds-averaged velocity fields near the outlet of the LES region in order to take downstream flow effects computed by the RANS model into account and dissipate the excessive turbulent fluctuations. This hybrid approach saves computational effort and makes it easier to properly specify inlet and outlet boundary conditions. Comparison between computational results and experimental data indicates that this relatively new modeling approach can accurately predict open-channel T-diversion flows.

A mixture model based approach for estimating the FDR in replicated microarray data

One of the mostly used methods for estimating the false discovery rate (FDR) is the permutation based method. The permutation based method has the well-known granularity problem due to the discrete nature of the permuted null scores. The granularity problem may produce very unstable FDR estimates. Such instability may cause scientists to over- or under-estimate the number of false positives among the genes declared as significant, and hence result in inaccurate interpretation of biological data. In this paper, we propose a new model based method as an improvement of the permutation based FDR estimation method of SAM [1] The new method uses the t-mixture model which can model the microarray data better than the currently used normal mixture model. We will show that our proposed method provides more accurate FDR estimates than the permutation based method and is free of the problems of the permutation based FDR estimators. Finally, the proposed method is evaluated using extensive simulation and real microarray data.

Constrained predictive control based on T-S fuzzy model for nonlinear systems

A constrained generalized predictive control （GPC） algorithm based on the T-S fuzzy model is presented for the nonlinear system. First, a Takagi-Sugeno （T-S） fuzzy model based on the fuzzy cluster algorithm and the orthogonalleast square method is constructed to approach the nonlinear system. Since its consequence is linear, it can divide the nonlinear system into a number of linear or nearly linear subsystems. For this T-S fuzzy model, a GPC algorithm with input constraints is presented. This strategy takes into account all the constraints of the control signal and its increment, and does not require the calculation of the Diophantine equations. So it needs only a small computer memory and the computational speed is high. The simulation results show a good performance for the nonlinear systems.

Design of TakagiSugeno fuzzy model based nonlinear sliding model controller

A design method is presented for Takagi-Sugeno （T-S） fuzzy model based nonlinear sliding model controller. First, the closed-loop fuzzy system is divided into a set of dominant local linear systems according to operating sub-regions. In each sub-region the fuzzy system consists of nominal linear system and a group of interacting systems. Then the controller composed two parts is designed. One part is designed to control the nominal system, the other is designed to control the interacting systems with sliding mode theory. The proposed controller can improve the robusmess and gnarantee tracking performance of the fuzzy system. Stability is guaranteed without finding a common positive definite matrix.

尖牙反[牙合]矫治人字形和T形曲组合正畸弓丝矫治力建模

固定矫治技术是治疗牙齿反[牙合]最为有效的矫治手段,主要通过正畸弓丝释放的矫治力来达到反[牙合]矫治中的矫治空间预留、反[牙合]牙齿回收的目的。在牙齿反[牙合]畸形中,尖牙反[牙合]是最为常见的牙齿反[牙合]畸形,常使用人字形和T形组合曲关闭上颌牙列间隙。本文旨在正畸治疗前量化人字形和T形组合曲释放矫治力的情况,为正畸医师提供尖牙反[牙合]矫治的理论参考。分析人字形和T形组合曲的形变过程,将其形变过程分为弹性形变和弹塑性形变两类,并对两种形变下的矫治力微分方程进行了构建,将其释放的矫治力分为闭隙矫治力和倾覆矫治力两种,完成了人字形和T形组合曲理论模型的建立,其次对有限元仿真值与理论值的误差率进行计算,得到闭隙矫治力仿真值与理论值的误差率在0.43%~8.33%之间,倾覆矫治力的仿真值与理论值的误差率在2.13%~9.76%之间,搭建实验测量平台得到了闭隙矫治力实验值与理论值误差率为0%~9.30%、倾覆矫治力实验值与理论值的误差率为0%~9.76%,实验测量数据与理论值具有相同的非线性变化趋势,验证了人字形和T形组合曲理论预测模型的正确性,该模型能帮助医师在治疗前对正畸力进行详细的定量分析,从而为个性化治疗方案的制定提供依据,更好地满足患者需求。

海洋石油工程固定式导管架平台T/K/Y节点马鞍口建模

海洋石油工程固定式导管架是海上油气资源开采的重要设施,是由钢管相贯焊接形成的空间桁架结构。导管架的主要焊接结构是T/K/Y节点,T/K/Y节点中存在大量的马鞍口结构。目前,对马鞍口的加工及焊接主要以二维图样贴片为主,尚无软件可实现管节点马鞍口的参数化三维建模。在分析马鞍口相贯线机理的基础上,建立马鞍口相贯线的数学模型,并基于此利用Unity3D编写了绘制马鞍口相贯线的通用软件,实现了马鞍口的参数化三维建模,有效解决了实际生产中T/K/Y节点马鞍口难以建模的问题,为管节点马鞍口的加工及智能焊接提供精确的模型。

Controller design of uncertain nonlinear systems based on T-S fuzzy model

A robust control for uncertain nonlinear systems based on T-S fuzzy model is discussed in this paper. First, a T-S fuzzy system is adopted to model the uncertain nonlinear systems. Then, for the system with input variables adopting standard fuzzy partitions, the efficient maximal overlapped-rules group （EMORG） is presented, and a new sufficient condition to check the stability of T-S fuzzy system with uncertainty is derived, which is expressed in terms of Linear Matrix Inequalities. The derived stability condition, which only requires a local common positive definite matrix in each EMORG, can reduce the conservatism and difficulty in existing stability conditions. Finally, a simulation example shows the proposed approach is effective.

Fuzzy modelling and impulsive control of the hyperchaotic L system

This paper presents a novel approach to hyperchaos control of hyperchaotic systems based on impulsive control and the Takagi-Sugeno （T-S） fuzzy model. In this study, the hyperchaotic Lu system is exactly represented by the T-S fuzzy model and an impulsive control framework is proposed for stabilizing the hyperchaotic Lu system, which is also suitable for classes of T-S fuzzy hyperchaotic systems, such as the hyperchaotic Rossler, Chen, Chua systems and so on. Sufficient conditions for achieving stability in impulsive T-S fuzzy hyperchaotic systems are derived by using Lyapunov stability theory in the form of the linear matrix inequality, and are less conservative in comparison with existing results. Numerical simulations are given to demonstrate the effectiveness of the proposed method.