控制污染物排放的支线机场跑滑结构优化仿真

民航运输在LTO(Landing and take-off)循环阶段的大气污染物排放对地面人员和近地环境危害较大,应主要通过减少地面滑行时间进行控制。考虑支线机场常见的单跑滑结构给出飞机地面滑行时间计算方法,基于该方法提出了污染物评价指标并建立了支线机场航空器污染物排放评估模型。以某支线机场为例,使用Matlab建模计算得出污染物评价指数最小滑行道口位置。利用AirTOp仿真验证了模型计算结果有效性,优化后的跑道出口位置将使该机场污染物总指数较原位置降低21.7%。     

考虑集装箱生命周期的空重箱班轮运输组织优化

为在空箱调运时考虑空箱的维修成本和废弃收益,根据投入使用的时间区分空箱所处的生命阶段.在备选班轮航线和重箱运输需求确定的情况下,构建混合整数规划模型,优化班轮航线网络,重箱运输路径,新造箱的投入地点,老旧空箱的报废地点和各航次使用哪个生命阶段的空箱来执行运输任务.以中国,日韩,东南亚,欧洲和美国五个区域为对象的实证分析结果表明,93%的新造箱在中国投入使用,64%的老旧空箱在欧洲和美国退役,74%的由中国到美国的运输用箱处于高龄阶段或退出阶段.     

预应力水冲桩抗裂性能研究分析

某码头工程下部结构采用预应力水冲锤击桩,试桩过程中发现,在贯入度较大的情况下桩身多处产生横向裂缝,使桩尖无法达到设计标高。为分析产生裂缝原因,通过静荷载试验的方法检验桩身的抗裂性能;结果表明张拉控制应力未达到设计值,是导致桩身产生环向裂缝的主要原因;提出适当调整预应力,能够有效地解决预应力水冲桩桩身裂缝的问题。     

北桥设计中的总线周期精确事务级建模

总线周期精确事务级建模能解决系统设计中的仿真精度和速度之间的矛盾。以北桥中的总线设计为背景,采用SystemC中接口方法调用的原理,实现了对Wishbone总线的周期精确事物级建模,并给出了具体的实现方法和测试方法,具有一定的通用性。     

完全图Kn分解成五个顶点的星和圈

讨论了完全图Kn分解成五个顶点的星和圈的存在性,给出完全图Kn存在{S5,C5}-强制分解的充要条件是n≥9.以及完全图Kn存在{S5,C5}-分解的充要条件是n≥5(n≠6,7).     

Forecasting key US macroeconomic variables with a factor‐augmented Qual VAR

In this paper, we first extract factors from a monthly dataset of 130 macroeconomic and financial variables. These extracted factors are then used to construct a factor‐augmented qualitative vector autoregressive (FA‐Qual VAR) model to forecast industrial production growth, inflation, the Federal funds rate, and the term spread based on a pseudo out‐of‐sample recursive forecasting exercise over an out‐of‐sample period of 1980:1 to 2014:12, using an in‐sample period of 1960:1 to 1979:12. Short‐, medium‐, and long‐run horizons of 1, 6, 12, and 24 months ahead are considered. The forecast from the FA‐Qual VAR is compared with that of a standard VAR model, a Qual VAR model, and a factor‐augmented VAR (FAVAR). In general, we observe that the FA‐Qual VAR tends to perform significantly better than the VAR, Qual VAR and FAVAR (barring some exceptions relative to the latter). In addition, we find that the Qual VARs are also well equipped in forecasting probability of recessions when compared to probit models.     

Predicting Recessions with Leading Indicators: Model Averaging and Selection over the Business Cycle

Four methods of model selection—equally weighted forecasts, Bayesian model‐averaged forecasts, and two models produced by the machine‐learning algorithm boosting—are applied to the problem of predicting business cycle turning points with a set of common macroeconomic variables. The methods address a fundamental problem faced by forecasters: the most useful model is simple but makes use of all relevant indicators. The results indicate that successful models of recession condition on different economic indicators at different forecast horizons. Predictors that describe real economic activity provide the clearest signal of recession at very short horizons. In contrast, signals from housing and financial markets produce the best forecasts at longer forecast horizons. A real‐time forecast experiment explores the predictability of the 2001 and 2007 recessions. Copyright © 2015 John Wiley & Sons, Ltd.     

商用车驱动桥壳的疲劳分析

运用CATIA建立某型商用车驱动桥壳的实体模型,利用Hypermesh划分网格,参照标准QC—T533规定的台架试验方法,对桥壳进行弯曲刚度、垂直静强度有限元仿真计算。通过量化分析应力集中、尺寸及表面加工情况等疲劳影响因素,引入疲劳寿命仿真分析。依据QC．T534规定的评价方法,桥壳上述指标均符合国家标准,仿真结果与试验结果一致。同时指出桥壳存在问题,为下一步优化指明方向。     

掘进工作面瓦斯涌出规律研究

通过对潘一矿掘进工作面涌出量进行实测,对工作面瓦斯涌出来源及构成进行了分析。利用回归分析法,找出了工作面落煤、煤壁瓦斯涌出规律,为工作面的通风管理与安全生产提供了必要的技术指导。     

基于NVH性能的排气系统悬挂点位置设计

基于平均驱动自由度位移（ADDOFD）理论,同时考虑车身侧与排气系统侧的NVH性能,以及各阶模态频率的不同权值的影响,对某车型排气系统吊点位置进行优化布置,并对布置吊点后的排气系统做声学稳健性分析。实际应用表明该设计方法能对汽车排气系统悬挂点选择提供可行性参考建议,在整车开发的初期,有效预测和控制车身结构的NVH性能。