Home Foreclosures and Neighborhood Crime Dynamics

We advance scholarship related to home foreclosures and neighborhood crime by employing Granger causality tests and multilevel growth modeling with annual data from Chicago neighborhoods over the period 1998–2009. We find that completed foreclosures temporally lead property crime and not vice versa. More completed foreclosures during a year both increase the level of property crime and slow its decline subsequently. This relationship is strongest in higher income, predominantly renter-occupied neighborhoods, contrary to the conventional wisdom. We did not find unambiguous, unidirectional causation in the case of violent crime and when filed foreclosures were analyzed.     

A numerical method for factorizing the rational spectral density matrix

Improving Rozanov (1967, Stationary Random Processes. San Francisco: Holden‐day.)’s algebraic‐analytic solution to the canonical factorization problem of the rational spectral density matrix, this article presents a feasible computational procedure for the spectral factorization. We provide numerical comparisons of our procedure with the Bhansali's (1974, Journal of the Statistical Society, B36 , 61.) and Wilson's (1972 SIAM Journal on Applied Mathematics, 23 , 420) methods and illustrate its application in estimation of invertible MA representation. The proposed procedure is usefully applied to linear predictor construction, causality analysis and other problems where a canonical transfer function specification of a stationary process in question is required.     

Use of crash surrogates and exceedance statistics to estimate road safety

The limited ability of existing safety models to properly reflect crash causality has its source in cross-sectional analysis applied to the estimation of the intrinsically complex safety factors with highly aggregated and frequently poor quality of data. The adequacy of the data may be improved thanks to the unprecedented progress in sensing technologies and the invention of the naturalistic driving method of data collection. Proposed in this paper is a new modeling paradigm that integrates several types of safety models. The primary improvement results from a more adequate representation of the crash occurrence process by incorporating crash precursor events into the modeling framework. A Pareto-based estimating method for the likelihood of a collision occurrence, given a precursor event, is explained and illustrated with the simple example of road departures.     

经济适用房推出比对商品房价格影响研究

应用香港、深圳住房市场历史数据,分别构建了香港居屋推出数量、深圳经济适用房推出比与房价变动Granger因果检验模型。发现房价水平可显著影响居屋、经济适用房的推出比;较高居屋推出数量可显著影响房价,而在经济适用房推出比较低情况下,推出比变化却无法影响房价。结论指出,当前为拉动经济发展、有效调节商品房价格水平,应积极提升经济适用房推出比、增强供给冗余、实现"建售分离"。     

定量化因果分析法在工程质量管理中的应用

因果分析法常用于对工程质量和产品质量问题的定性分析,但无法判断各因素的影响度。本文将系统分析的两种工具———层次分析法和因果分析法进行有机结合,提出了“定量化因果分析法”这一新概念,并用于建筑工程质量管理实践。     

从“资源诅咒”视角探究河北省威县产业扶贫路径

丰裕的自然资源对地区经济有一定的促进作用，但是过度依赖资源却会制约地区经济增长，使其陷入贫困。论文基于贫困地区益贫式的发展环境，从“资源诅咒”视角分析当前威县经济成功转型的原因，研究发现：威县资源依赖、技术进步、经济增长存在长期稳定的内在联系；威县创新型企业数量和FDI水平与威县技术进步水平存在因果关系；威县在当前大扶贫格局下，借助政策和区位优势提高产业技术水平，摆脱了“资源诅咒”的困扰，形成了长期稳定的产业扶贫路径，推动了威县后脱贫时代的巩固提升和经济长效增长。     

基于弹性网络模型的月度用电量预测方法

由于现有月度用电量预测所选影响因素较少,无法较为全面地反映与用电量强关联的因素,同时针对高维数据变量筛选和高精度预测等突出难题,文中提出了一种弹性网络用电量预测模型。为了考虑更为全面的影响因素,建立了用电量、气象、经济、交通4类,共340个变量的数据集。首先对8年96个点的高维变量数据进行弹性网络因子筛选,然后使用Granger因果关系分析找出了用电量数据与其它数据的关联关系,对一年范围内的全社会月度用电量使用弹性网络进行预测,预测结果的平均绝对百分误差为3.07%。为验证该模型的有效性,对比向量自回归(VAR)模型,反向传播(BP)模型和最小绝对值收缩和选择算子(Lasso)预测的效果,验证了文中所提方法预测精度较高。     

双曲柄串联曲柄滑块压力机机构计算机仿真向量键合图法

为提高双曲柄串联曲柄滑块压力机机构动力学建模与仿真的效率及可靠性,提出了相应的向量键合图法。根据机构构件间的运动约束关系,将机构运动构件、旋转铰及移动副的向量键合图模型组合起来,建立了双曲柄串联曲柄滑块压力机机构的向量键合图模型。通过有效的增广方法,消除了机构向量键合图模型中的微分因果关系,克服了其给机构自动建模所带来的代数困难。在此基础上,实现了双曲柄串联曲柄滑块压力机机构动力学自动建模与仿真,分析了脉冲形式的工作阻力对机构动态性能的影响,说明了所述方法的有效性。     

区域性固定资产投资因果关系实证分析

应用单位根检验对我国三大经济区域的名义固定资产投资和名义生产总值进行平稳性检验,并使之成为平稳性序列,继而应用格兰杰因果关系检验,分析我国三大经济区域固定资产投资与生产总值之间的因果关系,最后对我国固定资产投资在三大经济区域的取向提出建议.     

企业管理者任职资格确定的定性模拟方法

首先提出了用于企业管理者任职资格确定定性模拟因果关系模型；然后设计了变量的知识表达与转换方法、定性分支的过滤方法以及定性模拟的步骤，并讨论了模拟结果的应用；最后给出了一个模拟实例。