PATTERN RECOGNITION VIA ROBUST SMOOTHING WITH APPLICATION TO LASER DATA

Nowadays airborne laser scanning is used in many territorial studies, providing point data which may contain strong discontinuities. Motivated by the need to interpolate such data and preserve their edges, this paper considers robust nonparametric smoothers. These estimators, when implemented with bounded loss functions, have suitable jump‐preserving properties. Iterative algorithms are developed here, and are equivalent to nonlinear M‐smoothers, but have the advantage of resembling the linear Kernel regression. The selection of their coefficients is carried out by combining cross‐validation and robust‐tuning techniques. Two real case studies and a simulation experiment confirm the validity of the method; in particular, the performance in building recognition is excellent.     

关系型贷款、市场结构与小额贷款公司使命漂移

我国小额贷款公司发展极为迅速,但小微企业融资难问题依然严峻,小额贷款公司存在着显著的使命漂移.对于微型金融机构的使命漂移问题,大量的研究主要以财务可持续性为视角.本文结合关系型贷款理论和市场结构理论并构建理论模型,以一个新的视角分析我国小额贷款公司的使命漂移问题,证明了开展关系型贷款和提升小额贷款市场的竞争程度均有利于小额贷款公司发放更多的小额贷款,增加小微企业等融资主体的信贷可得性,从而避免使命漂移.进一步的,通过对一个代表性城市小额贷款公司的相关数据分析,认为小额贷款公司使命漂移的内在原因是关系型贷款技术运用不足和小额贷款市场竞争程度较低.     

Threshold Estimation for Stochastic Processes with Small Noise

Consider a process satisfying a stochastic differential equation with unknown drift parameter, and suppose that discrete observations are given. It is known that a simple least squares estimator (LSE) can be consistent but numerically unstable in the sense of large standard deviations under finite samples when the noise process has jumps. We propose a filter to cut large shocks from data and construct the same LSE from data selected by the filter. The proposed estimator can be asymptotically equivalent to the usual LSE, whose asymptotic distribution strongly depends on the noise process. However, in numerical study, it looked asymptotically normal in an example where filter was chosen suitably, and the noise was a Lévy process. We will try to justify this phenomenon mathematically, under certain restricted assumptions.     

章炳麟的《成均图》及“音转理论”

文章通过分析<成均图>,并与孔广森的"对转"学说相比较,进一步探讨、评价了章炳麟的"音转理论".     

新吉坪隧道斜井进正洞挑顶施工技术研究

沪昆铁路客运专线新吉坪隧道所处地质条件复杂，区域地质作用剧烈，碳酸岩分布广泛，不良地质特别发育。针对斜井进正洞施工，提出了纵向爬坡导坑法。并以2#斜井为例，介绍了纵向爬坡导坑法施工工艺和斜井进正洞挑顶施工的控制要点，以及在施工过程中的控制量测方法，为新吉坪隧道斜井进正洞挑顶施工提供了技术指导，为类似工程施工提供参考。     

20世纪90年代以来乡土移民小说的苦难叙事

乡土移民小说是指那些“专门关注漂流进城市的广大民工生活的新的文学样式”。乡土移民小说描写的是乡土大地一颗颗执拗朴实的心灵个体或主动或无奈地告别乡土走向城市的不同文化心理和价值观念的冲突、居无定所价值丢失造成的肉身和灵魂的孤独漂泊。这类小说的苦难意识非常突出，并且独具特色。它的出现一方面与社会公众期待视野有关，另一方面从这些移民叙事中看到了久违的现实主义精神，但遗憾的是，很多小说都停留在对农民生存苦难的自然主义的揭示，丧失了人性批判的创作立场，体现了当今消费社会的审美趣味。     

单向不连续碳纤维增强热塑性树脂基复合材料弹塑性应力分析

本文采用有限元法，建立了有关的单胞模型和相关的边界条件．着重研究了单向不连续碳纤维增强聚醚醚酮复合材料的细观弹塑性应力应变关系，分析了纤维端都的不连续性对复合材料中纤维与纤维，纤维与周围基体相互作用以及应力场变化的影响．此外利用体积平均法预测了在外载荷作用下单向不连续碳纤维增强复合材料的弹塑性应力-应变关系．     

论“科研漂移”对我国大学的负面影响及其对策（上）

“科研漂移”是指科研活动从大学的教学单位和中心课程构架中分离出去的现象。在我国，“科研漂移”主要表现为：高等教育的科技经费投入总量和人均值都低于科研机构和大中型企业；高校之间的科研资源分配向部属大学、重点大学和综合大学集中，很不均衡；大量的发明专利向科研机构和工矿企业转移以及大学内部科研与教学的分离。导致“科研漂移”的主要原因是由前苏联传承而来的科学院与高校相互分离的制度、高等教育的“金字塔”结构和高校内部科研与教学的职能分离。“科研漂移”对大学的负面影响表现为：人文、科学研究的智慧成就不能及时有效地传递到下一代人，降低了高校人才培养的水平，体现不出真正意义上的高等教育。消除“科研漂移”现象的基本对策是：改革现行科学院与普通高校相互分离的制度，重新组合科学院与普通高校之间的关系，科技资源应当依据大学的类别层次进行相对均衡的分配，坚持洪堡大学理念。     

Computing optimal adjustment schemes for the general tool-wear problem

An important problem in process adjustment using feedback is how often to sample the process and when and by how much to apply an adjustment. Minimum cost feedback schemes based on simple, but practically interesting, models for disturbances and dynamics have been discussed in several particular cases. The more general situation in which there may be measurement and adjustment errors, deterministic process drift, and costs of taking an observation, of making an adjustment, and of being off target, is considered in this article. Assuming all these costs to be known, a numerical method to minimize the overall expected cost is presented. This numerical method provides the optimal sampling interval, action limits, and amount of adjustment; and the resulting average adjustment interval, mean squared deviation from target, and minimum overall expected cost. When the costs of taking an observation, of making an adjustment, and of being off target are not known, the method can be used to choose a particular scheme by judging the advantages and disadvantages of alternative options considering the mean squared deviation they produce, the frequency with which they require observations to be made, and the resulting overall length of time between adjustments. Computer codes that perform the required computations are provided in the appendices and applied to find optimal adjustment schemes in three real examples of application.     

隐含概念漂移的数据流分类算法研究

数据流具有快速性、连续性、多变性及无限性等特性，使得传统的分类方法不再适用。由于数据流多变的特性，设计高效、高精度的分类算法是比较困难的。目前数据流在电信、网络等众多应用领域客观大量存在，因此研究快速的、精确的、稳定的数据流分类系统具有较高的理论价值和应用前景。近年来，大量的研究工作都旨在高效准确地解决隐含概念漂移的数据流的分类问题。本文研究了一些适合数据流的分类算法，根据算法主要思想的不同进行分类，根据每种思想的发展历程对其相应的算法进行论述，并对部分经典算法分析其处理概念漂移的性能，并对进一步可做的工作进行展望。