A new estimation approach for the multiple discrete–continuous probit (MDCP) choice model

This paper develops a blueprint (complete with matrix notation) to apply Bhat’s (2011) Maximum Approximate Composite Marginal Likelihood (MACML) inference approach for the estimation of cross-sectional as well as panel multiple discrete–continuous probit (MDCP) models. A simulation exercise is undertaken to evaluate the ability of the proposed approach to recover parameters from a cross-sectional MDCP model. The results show that the MACML approach does very well in recovering parameters, as well as appears to accurately capture the curvature of the Hessian of the log-likelihood function. The paper also demonstrates the application of the proposed approach through a study of individuals’ recreational (i.e., long distance leisure) choice among alternative destination locations and the number of trips to each recreational destination location, using data drawn from the 2004 to 2005 Michigan statewide household travel survey.     

海绵城市生物渗滤单元填料对城市道路径流污染物处理效果的实验研究

通过对海绵城市生物渗滤单元几种常见的填料及其在不同配比下对于城市道路径流中的Zn、总P和石油类三种代表性污染物处理效果的实验分析，考察了不同填料对城市道路径流污染物的去除效果。结果表明，河砂的去除效果好于沸石。实验期间，河砂柱对锌的去除率均高于95%， 而沸石柱在通水的前三天内对锌的去除率高于90%，随后逐渐降低。在河砂中适当添加少量砾石有助于在保证去除率的情况下提高其渗透速率， 当河砂与砾石质量比为2∶1时，填充柱的渗透速率达到4 mm/min，同时其对各污染物的去除效果也很明显。     

基于径向基函数网络的社会消费品总额预测模型

利用BP、RBF神经网络自适应学习法模型,对社会消费品总额进行了预测和研究,结果表明用RBF网络自适应学习法所建立的模型经过训练后,可得到较精确的预测结果,并具有较强的应用性。     

频谱分析的一类新算法

本文指出可替代ＦＦＩ法的一类频谱分析新算法，它们以功率谱形式给出，文中给出一个构造算创并与同类算法作了比较。     

THE CHANGES OF CHILDREN′S BEHAVIOR PROBLEMS IN XI′AN DURING FIVE YEARS FROM 1988 TO 1993

ＢｙｕｓｉｎｇＣＢＣＬ（ＣｈｉｌｄＢｅｈａｖｉｏｒＣｈｅｃｋｌｉｓｔ）ｏｆＸｉ′ａｎｎｏｒｍ，ｔｈｅｃｈｉｌｄｒｅｎ＇ｓｂｅｈａｖｉｏｒｐｒｏｂｌｅｍｓｉｎＸｉ′ａｎｈａｖｅｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄａｎｄｃｏｍｐａｒｅｄｗｉｔｈｔｈｅｒｅｓｕｌｔｓｏｂｔａｉｎｅｄｂｅｆｏｒｅ１９９３，ｔｈｅｐｏｓｉｔｉｖｅｒｅｓｕｌｔｓｐｒｏｖｉｄｅｓｃｉｅｎｔｉｆｉｃｂａｓｉｓｆｏｒｄｉａｇｎｏｓｉｓａｎｄｒｅｆｅｒｅｎｃｅｆｏｒｔｅａｃｈｅｒｓ．ＭＡＴＥＲＩＡＬＳＡＮＤＭＥＴＨＯＤＳＴｈｅｐｕｐｉｌ…     

Transportation agencies experiences with decision support systems for airport ground access planning

This article reports on a field investigation into the ways that transportation agencies use quantitative and qualitative information for making strategic decisions regarding airport ground access. The study analyzes the value of this information for planning airport ground access improvements at seven major international airport sites.The major finding of the research is that quantitative modeling for strategic decision support is very difficult, costly and time consuming. Modelers are confident that the models are accurate and reliable but executives generally lack confidence in the results. Transportation officials believe that the information supplied is flawed by a number of defects that minimize its value for strategic decision makers. The information defects described in this article provide an analysis of the structural difficulty of using quantitative modeling for transportation problems of strategic importance. To date, qualitative information is not frequently used, but some transportation agencies are considering its application to designing transportation services. Although this study is limited to airport ground access, the authors feel that this evidence, in conjunction with the evidence from other studies in the transportation area, dictates a need for wariness in the development of decision support systems for transportation planners. Developers of decision support systems for transportation planners must be aware of modeling costs and defects and consider how to improve the timeliness, relevance and credibility of information quantitative models provide transportation executives. Fundamentally it is important to recognize that decision makers tend, either singularly or in concert with other individuals or groups, to be the champions of a long-term vision for the community. When modeling produces inconsistent or wide ranging results that contradict their position, decision makers may not only discard modeling activities, but lose confidence in the models altogether. As a consequence, transportation planners are faced with the challenge of how to improve quantitative modeling. The most reliable and effective means for improvement is incorporation of qualitative techniques which provide greater understanding of customer perceptions and human behavior.     

基于时间序列法的舰船运动预报实验研究

采用线性自回归AR模型、具有首前波观测量的ARMA模型以及非线性自回归NAR模型三种方法分别对舰船运动进行预报,将得到的预报结果与实验测量结果进行验证比较,并对最佳预报模式进行讨论.     

全长粘结岩锚抗拔受力特性

根据锚杆与锚固浆之间界面耦合机理,分析了岩锚抗拔状态下界面剪应力的分布特征。基于变形协调得出小荷载情况下界面剪应力随离锚固受力点距离的增大成指数衰减,并随荷载增加,界面出现4个变形段,分离段和残余变形段随着塑性区开展产生非耦应力向远端传递。耦合区界面剪应力分布与小荷载情况不同,其相关模量参数可采用综合折减系数表示。同时,提出了单孔多锚杆受力剪应力衰减模型,并通过试验证示了现场锚杆在荷载逐级加大时,剪应力峰值强度的变化规律。     

混合交通流参数之间关系模型标定

提出了混合交通流参数之间关系模型的标定和超车换道率的计算方法,采用广深高速公路、广佛高速公路和沪宁高速公路的实测数据对模型进行了验证,并计算了各数据点的超车换道率.结果表明,流量、密度数据的相关系数都接近1,超车换道率介于-1和1之间.     

铁路罐式集装箱空箱调配优化模型及遗传模拟退火算法

针对罐式集装箱运输的特殊性,考虑重箱流和空箱流调配的综合优化,以罐箱运输费用最小为目标,建立铁路罐式集装箱空箱调配优化多商品网络流模型,并构造了1种嵌入模拟退火操作的遗传算法对之进行求解。为了使模型与算法可得到更符合实际、操作性更强的结果,给出了3种空罐箱调配的策略,作为隐含条件加入到算法求解过程中。利用自适应遗传模拟退火算法对随机生成的实际规模问题算例进行求解,并与用通用代数建模系统软件GAMS的计算结果进行对比。结果表明,前者得出的结果与最优解差距不大,而且运算速度更快,更能满足解决实际问题的需要,为铁路罐箱调配优化提供了良好的决策支持模型和算法。