共查询到20条相似文献，搜索用时 31 毫秒
1.
基于因素修正法的征地统一年产值测算方法——以广西壮族自治区桂平市为例 总被引：2，自引：0，他引：2
征地统一年产值的测算是一项政策性强的复杂工作，其测算结果关系到农民的切身利益和经济建设的健康发展。而选择恰当的测算方法是保证征地统一年产值测算结果科学合理的重要前提之一。针对现行征地补偿标准测算方法存在欠严谨、弹性较大等问题，文章以桂平市为例，采用因素修正法，以前3年桂平市的主要农产品平均产量、价格为主要依据，初步测算桂平市的统一年产值。同时，遴选出影响土地综合收益的主要因素，通过多因素综合评价，定性和定量相结合等方法，编制出一套可操作性强的统一年产值因素修正体系，以桂平市统一年产值为基数修正计算，求取各测算单元的统一年产值。经实际运用表明，该方法操作简便，弥补了数据资料不全、统计口径不一的不足，减少了测算过程中的经验判断和主观因素的影响，使征地统一年产值标准的测算结果更趋合理，对于各级国土资源部门宏观平衡各地的征地统一年产值标准有重要的理论和实践意义，值得在征地统一年产值测算中推广应用。 相似文献
2.
Yibing Sun Minyue Fu Bingchang Wang Huanshui Zhang 《Journal of The Franklin Institute》2017,354(14):6200-6216
In this paper, we consider a distributed dynamic state estimation problem for time-varying systems. Based on the distributed maximum a posteriori (MAP) estimation algorithm proposed in our previous study, which studies the linear measurement models of each subsystem, and by weakening the constraint condition as that each time-varying subsystem is observable, this paper proves that the error covariances of state estimation and prediction obtained from the improved algorithm are respectively positive definite and have upper bounds, which verifies the feasibility of this algorithm. We also use new weighting functions and time-varying exponential smoothing method to ensure the robustness and improve the forecast accuracy of the distributed state estimation method. At last, an example is used to demonstrate the effectiveness of the proposed algorithm together with the parameter identification. 相似文献
3.
In this paper, we consider the parameter estimation issues of a class of multivariate output-error systems. A decomposition based recursive least squares identification method is proposed using the hierarchical identification principle and the auxiliary model idea, and its convergence is analyzed through the stochastic process theory. Compared with the existing results on parameter estimation of multivariate output-error systems, a distinct feature for the proposed algorithm is that such a system is decomposed into several sub-systems with smaller dimensions so that parameters to be identified can be estimated interactively. The analysis shows that the estimation errors converge to zero in mean square under certain conditions. Finally, in order to show the effectiveness of the proposed approach, some numerical simulations are provided. 相似文献
4.
隐马尔科夫模型在很多方面已有广泛应用.讨论了一类更为一般的模型,这类模型由Wojciech
Pieczynski首次提出,并且给出了在图像识别中的应用.这里首次给出在离散观测和离散状态下该模型的精确数学描述,其中包括建模、状态估计和参数估计,这些算法都是首次被提出的. 相似文献
5.
In this paper, we present a secure distributed estimation strategy in networked systems. In particular, we consider distributed Kalman filtering as the estimation method and Paillier encryption, which is a partially homomorphic encryption scheme. The proposed strategy protects the confidentiality of the transmitted data within a network. Moreover, it also secures the state estimation computation process. To this end, all the algebraic calculations needed for state estimation in a distributed Kalman filter are performed over the encrypted data. As Paillier encryption only deals with integer data, in general, this, in turn, provides significant quantization error in the computation process associated with the Kalman filter. However, the proposed estimation approach handles quantized data in an efficient way. We provide an optimality and convergence analysis of our proposed method. It is shown that state estimation and a covariance matrix associated with the proposed method remain with a certain small radius of those of a conventional centralized Kalman filter. Simulation results are given to further demonstrate the effectiveness of the proposed scheme. 相似文献
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This paper considers the identification problem of bilinear systems with measurement noise in the form of the moving average model. In particular, we present an interactive estimation algorithm for unmeasurable states and parameters based on the hierarchical identification principle. For unknown states, we formulate a novel bilinear state observer from input-output measurements using the Kalman filter. Then a bilinear state observer based multi-innovation extended stochastic gradient (BSO-MI-ESG) algorithm is proposed to estimate the unknown system parameters. A linear filter is utilized to improve the parameter estimation accuracy and a filtering based BSO-MI-ESG algorithm is presented using the data filtering technique. In the numerical example, we illustrate the effectiveness of the proposed identification methods. 相似文献
9.
不同潜在蒸散发估算方法在辽宁省的适用性分析 总被引：1，自引：0，他引：1
准确估算潜在蒸散发（PET）是研究区域水文循环和农业灌溉管理必不可少的理论依据。本文利用辽宁省及周边27个气象站点1968—2017年的历史气象数据,选用6种估算方法（Penman-Monteith（PM）法、Rohwer（Roh）法、Hamon（Ham）法、Hargreaves（Har）法、Makkink（Mak）法和Priestley-Taylor（PT）法）计算PET。并以PM法月值作为标准,对5种估算方法的经验系数进行修正,再从年、月两个时间尺度和空间尺度分析修正经验系数前后5种估算方法在辽宁省的适用情况。结果表明：①修正前,年尺度上,Mak法、PT法和PM法的结果较为接近,相对误差均在25%以内。月尺度上,PT法相对误差最小为13.96%,其次是Mak法。空间尺度上,5种估算方法在辽东北地区估算精度较低,整体空间差异明显,相对来说PT法估算适用性更好。②修正后,5种估算方法适用性和相关性都有明显的提高,在年尺度上各估算方法与PM法计算结果年际变化大致相同,其中Mak法和PT法最为合适,相对误差均在10%以内,月尺度和空间尺度上,PT法都优于其他方法。因此,在计算辽宁省PET时,本文推荐使用修正经验系数后的PT法,其次是Mak法。 相似文献
10.
Qinyao Liu Feng Ding Yan Wang Cheng Wang Tasawar Hayat 《Journal of The Franklin Institute》2018,355(15):7643-7663
This paper focuses on the parameter estimation problem of multivariate output-error autoregressive systems. Based on the decomposition technique and the auxiliary model identification idea, we derive a decomposition based auxiliary model recursive generalized least squares algorithm. The key is to divide the system into two fictitious subsystems, the one including a parameter vector and the other including a parameter matrix, and to estimate the two subsystems using the recursive least squares method, respectively. Compared with the auxiliary model based recursive generalized least squares algorithm, the proposed algorithm has less computational burden. Finally, an illustrative example is provided to verify the effectiveness of the proposed algorithms. 相似文献
11.
Fu-Yuan Hsu Hahn-Ming Lee Tao-Hsing Chang Yao-Ting Sung 《Information processing & management》2018,54(6):969-984
Pretesting is the most commonly used method for estimating test item difficulty because it provides highly accurate results that can be applied to assessment development activities. However, pretesting is inefficient, and it can lead to item exposure. Hence, an increasing number of studies have invested considerable effort in researching the automated estimation of item difficulty. Language proficiency tests constitute the majority of researched test topics, while comparatively less research has focused on content subjects. This paper introduces a novel method for the automated estimation of item difficulty for social studies tests. In this study, we explore the difficulty of multiple-choice items, which consist of the following item elements: a question and alternative options. We use learning materials to construct a semantic space using word embedding techniques and project an item's texts into the semantic space to obtain corresponding vectors. Semantic features are obtained by calculating the cosine similarity between the vectors of item elements. Subsequently, these semantic features are sent to a classifier for training and testing. Based on the output of the classifier, an estimation model is created and item difficulty is estimated. Our findings suggest that the semantic similarity between a stem and the options has the strongest impact on item difficulty. Furthermore, the results indicate that the proposed estimation method outperforms pretesting, and therefore, we expect that the proposed approach will complement and partially replace pretesting in future. 相似文献
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新旧会计准则在资产减值的有关规定相比,主要变化之一是明确了资产可回收金额的估计方法。文章主要是探讨新会计准则对资产可回收金额的确认,特别是对公允价值的确认和预计末来现金流量的确认进行了有针对性的总结,以期对新准则的实施有所帮助。 相似文献
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In this paper, we present a fault-tolerant control (FTC) framework for a class of nonlinear networked control systems (NCSs). Firstly, the plant is transformed into two subsystems with one of them decoupled from the system fault. Then, the nonlinear observer is designed to provide the estimation of unmeasurable state and modelling uncertainty, which are used to construct fault estimation algorithm. Considering the sampling intervals occurred by net, a fault-tolerant control method is proposed for such nonlinear NCSs using the impulsive system techniques. The controller gain and the maximum sampling interval, which make the faulty system stable are given. An example is included to show the efficiency of the proposed method. 相似文献
14.
In this work, we present a new approach for loss probability estimation in a single server link. We show how to get the estimates analytically once we assume multifractal input traffic. In order to make the estimation procedure numerically tractable without losing the accuracy, we propose the use of a Gaussian mixture model to represent the heavy tail distribution of modern network traffic trace. The adopted evaluation procedure is based on two performance measures: empirical traffic arrival load distribution and loss probability at connection. Extensive experimental tests validate the efficiency and accuracy of the proposed loss probability estimation approach against the results obtained by simulations with real traffic and by comparing with other multifractal approaches suggested in the literature. 相似文献
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对基于均衡约束数学规划(MPEC)的数据分类模型进行改进.在确定数据所服从分布的密度函数(高斯混合模型来模拟)的参数时,使用β似然估计来代替原模型中的最大似然估计.新模型可以克服似然函数可能出现无界的现象,在计算上有更好的鲁棒性.对于所得MPEC分类模型,使用filterSQP方法将其作为非线性规划求解.数值试验显示了新模型的有效性. 相似文献
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粮食重视面积提取方法的发展与现状 总被引：16，自引：1，他引：16
粮食估产是我国长期以来进行的一项重要课题。近年来随着计算机技术和GPS技术的迅速发展，在种植面积提取方法上有了较大的进展。该文结合RS、GIS、GPS一体化体系，对农情采样系统的理论依据与工作方法进行了深入研究，在总结以往采样工作的基础上，提出了对统计资料进行一致性检验，分区建立采样线的方法。同时提出了用GIS归纳方法建立样线BUFFER区模型，从理论方面对采样方法进行讨论，从而完善了整个系统的理论基础。 相似文献
17.
In this paper, the state estimation problem is studied for a class of discrete-time stochastic complex networks with switched topology. In the network under consideration, we assume that measurement outputs can be got from only partial nodes, besides, the switching rule of this network is characterized by a sequence of Bernoulli random variables. The aim of the presented estimation problem is to develop a recursive estimator based on the framework of extended Kalman filter (EKF), such that the upper bound for the filtering error convariance is optimized. In order to address the nonlinear functions, the Taylor series expansion is utilized and the high-order terms of linearization errors are expressed in an exact way. Furthermore, by solving two Ricatti-like difference equations, the gain matrix can be acquired at each time instant. It is shown that the filtering error is bounded in mean square under some conditions with the aid of stochastic analysis techniques. A numerical example is given to demonstrate the validity of the proposed estimator. 相似文献
18.
Wei Xue Mei Zhang Shilong Liu Yongli Li Shijian Cang 《Journal of The Franklin Institute》2019,356(10):5378-5394
In this paper, we present the dimensionless form of a chaotic permanent magnet synchronous motor (PMSM). Its Kolmogorov formalism, which can be used to describe dissipative-forced dynamical systems, shows that there exist four types of torques, i.e., inertial torque, internal torque, dissipative torque and external torque. The mechanical analysis of the dimensionless PMSM is given for five different combinations of these torques. Numerical simulations show that the occurrence of chaos depends on these four types of torques. Moreover, the ultimate boundary estimation of the dimensionless chaotic PMSM is also investigated theoretically and numerically. 相似文献
19.
Orthogonal frequency division multiplexing (OFDM) has been widely adopted in radar and communication systems. High sensitivity to carrier frequency offset (CFO) is one of the major drawbacks of OFDM. CFO estimation for OFDM systems had been extensively studied and various algorithms had been proposed. However, the established algorithms may be compromised by the adoption of direct-conversion architecture and multi-mode low noise amplifier in the OFDM receiver, which introduces time-varying direct current offset (TV-DCO) into the system. In our previous study, we developed an eigen-decomposition based estimation algorithm, which is robust to TV-DCO but suffers from performance degradation under low to medium signal-to-noise ratio and requires high computation efforts. To address those issues, we in this paper propose a novel blind CFO estimation algorithm. By making use of the second order differential filtering and subspace method, the proposed algorithm achieves great performance improvement with reduced complexity. The performance of the proposed algorithm is demonstrated by simulations. 相似文献
20.
《Journal of The Franklin Institute》2023,360(12):8178-8199
In large-scale complex dynamical networks, it is significant to estimate the states of target nodes with only a part of measured nodes. Meanwhile, multilayer complex dynamical networks exist widely in society and engineering. Therefore, it has important theoretic meaning and practical value to study the state estimation of target nodes in multilayer complex dynamical networks with limited node measurements. In this paper, with the measurable state information of a portion of nodes in one layer in the multilayer complex dynamical network, the state estimation of target nodes in other layers is studied. First, we build the model of the multilayer complex dynamical network which includes some target nodes and sensor nodes. Second, auxiliary nodes are selected by using the maximum matching principle in graph theory to construct the augmented node set. Third, we discuss the relationship between the minimum number of auxiliary nodes and interlayer connection probability in the multilayer complex dynamical network. Forth, an appropriate functional state observer is designed with limited number of measured nodes according to a typical model-based algorithm. Finally, numerical simulations are given to demonstrate the accuracy of the proposed method. The proposed method can achieve the accurate estimation with less placement of observers and fewer computational costs in the multilayer complex dynamical network. 相似文献