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91.
欧龙 《昆明冶金高等专科学校学报》2012,28(5):73-75
“就业导向、工学结合”已成为高等职业教育人才培养模式改革的重要切入点,这给作为主干专业课程的“地籍与房产测量”教学带来全新的课题.为了构建适应这种新形势的教学模式,分别从教材建设、教学内容、教学手段、实践教学和考试形式5个方面进行了探索. 相似文献
92.
Mass appraisal of residential apartments: An application of Random forest for valuation and a CART-based approach for model diagnostics 总被引:1,自引:0,他引:1
To the best knowledge of authors, the use of Random forest as a potential technique for residential estate mass appraisal has been attempted for the first time. In the empirical study using data on residential apartments the method performed better than such techniques as CHAID, CART, KNN, multiple regression analysis, Artificial Neural Networks (MLP and RBF) and Boosted Trees. An approach for automatic detection of segments where a model significantly underperforms and for detecting segments with systematically under- or overestimated prediction is introduced. This segmentational approach is applicable to various expert systems including, but not limited to, those used for the mass appraisal. 相似文献
93.
Zhiping Zhou 《Polymer》2004,45(4):1313-1320
According to the six-state scheme proposed by Vacatello and Flory, the mean-square dipole moments 〈M2〉/x (x: number of monomeric units) of poly(methyl methacrylate) (PMMA) chains and their temperature dependence were calculated by the matrix algebra method of rotational isomeric state theory. To take account of the orientation effect of polar ester groups, the statistical weight matrices, U′ and U″, were recast into an expanded form. A Bernoullian probability λ introduced to measure the preference between the two alternative orientations (χ=0 and χ=π) of the side ester groups was found to give rise to a large effect on the mean-square dipole moment of polymers. When the skeletal bonds of a meso dyad are both in trans, an exceptionally strong dipole-dipole interaction may take place. If the two adjacent ester groups adopt the same orientation, the dipoles must be situated nearly parallel to each other in a close proximity. Such repulsive interactions may be alleviated by taking a staggered conformation, i.e. (χ,χ′)=(0,π) or (π,0). Such neighbor-dependent correlation inherent to the meso dyad is considered by assigning a parameter λ′ to the proper element of the Um″ matrix. The values of 〈M2〉/x observed at 30 °C were satisfactorily reproduced by adopting λ=0.270 and λ′=0.865. The thermal coefficients were found to be reconciled with the available experimental data by allowing the orientation parameters λ and λ′ to be slightly temperature dependent. The stereochemical characteristics of the chain terminals were examined in order to extend the treatment to include the dipole moment of PMMA oligomers. 相似文献
94.
Deyang Qu 《Electrochimica acta》2003,48(12):1675-1684
The proton diffusion coefficient in γ-MnO2 at various stages of discharge of an electrolytic manganese dioxide electrode has been determined taking into consideration the true molar volume and the electrochemically accessible surface area of MnO2. The unique electrochemical cell which allows the electrode expansion during the discharge to be monitored in situ was reported. The a.c. impedance technique and the transmission line equivalent circuit were used. Electrode ohmic resistance, Faradaic resistance, and double-layer capacitance were also obtained by means of numerical fitting of the impedance data using the transmission line model. 相似文献
95.
对多部电梯进行综合调控管理具有广泛的现实意义,本文提出了在乘客等待条件下的电梯调度问题,以作为上班高峰期电梯优化调度的一种近似。并利用概率论的方法得到了电梯往返运行一次的平均时间,建立了电梯优化调度的数学模型,且采用动态规划的方法求得了乘客在等待条件下的最优调度方案,并对实例进行了计算。 相似文献
96.
97.
根据离子交换原理建立了离子交换系统模型。并以钨离子交换为例。编写仿真软件求解该模型,获得淋洗曲线及各交换参数,通过与实验结果验证,计算机仿真数据与实验结果大致一致。 相似文献
98.
99.
The logarithmic model is often used to describe the relationships between factors.It often gives good statistical characteristics.Yet,in the process of modeling of soil and water conservation,we find out that this“good”model cannot guarantee good result.In this paper we make an inquiry into the intrinsic reasons.It is shown that the logarithmic model has the property of enlarging or reducing model errors,and the disadvantages of the logarithmic model are analyzed. 相似文献
100.
Regional Geological Information System combines the multi-dimensional and dynamic spatial information into an integrated spatial information system. 3D geological modeling and its preprocessing or post-processing are the most difficult problems for constructing the system. Based on the current 3D GIS technique, some basic problems in establishing the system are discussed in this paper, including 3D spatial data model, 3D geological modeling, and visualization of 3D geological data. A kind of 3D vector data model based on boundary representation for geological object and its topology was developed in order to model and visualize complex geological structures. In addition, some key techniques are pointed out for further study. 相似文献