地铁隧道结构断面测量方法探讨及编程实现

地铁隧道的结构断面测量是铺轨建设期间的一项重要工作,常规的测量方法内外业工作量较大,内业处理较为繁琐,数据计算效率较为低下。为了尽可能提高测量工作效率,减少仪器成本及人工成本,探讨了在地铁隧道内的控制点上架设全站仪,采用三维坐标测量的方法测得每个结构断面的特征点坐标,进而计算相应的断面尺寸偏差,并用C#编程语言编制了计算软件,使数据处理更为方便。工程实践表明,相比传统测量方法,该方法可以减少一定的外业工作量,同时内业数据处理相对简单便捷,效率高,可为类似工程提供参考。     

Carbon and nutrient dynamics in a hypertrophic lagoon in southwestern Taiwan

Dissolved and particulate phases of carbon (DIC, DOC, POC) and nutrients (DIN, DIP, DSi, DON, DOP, PN) were investigated bimonthly from August 1999 to August 2000 to study biogeochemical dynamics of carbon and nutrients in Tapong Bay, a small semi-enclosed and hypertrophic lagoon in southwestern Taiwan. The lagoon has only a tidal inlet for exchanging water between Tapong Bay and Taiwan Strait, which may result in low water exchange rates and various oxygen-deficient conditions in bottom water of the inner bay during warm seasons. The water exchange time of Tapong Bay ranges from 7 days (summer) to 13 days (winter) with a mean of 10 days. Nutrient dynamics were largely ascribed to allochthonous inputs, biological and exported removals in the lagoon. Diffusion fluxes from sediments to overlying water accounted for only about 7.6% of annual DIN inputs and 1.0% of annual DIP inputs. High primary productivity (89 mol C m⁻² year⁻¹) supported by abundant nutrients primarily drove the lagoon into a hypertrophic condition as particulate organic matter was derived mainly from biological production. Excess of DIP appeared to occur throughout the study period in the lagoon. Temperature, solar radiation and turbidity, rather than nutrients, perhaps controlled seasonal variations of primary productivity. The net ecosystem production (NEP) derived from daily changes of DOC and POC inventories was about 6.3 mmol C m⁻² day⁻¹ that was close to 6.7 mmol C m⁻² day⁻¹ simulated from the biogeochemical modeling. Therefore, the net ecosystem production (NEP) rate of organic carbon estimated from the biogeochemical model was reliable, and the NEP was temporally variable with an annual mean of 5.8 mol C m⁻² year⁻¹, implying that Tapong Bay was an autotrophic system. Although calcification proceeded pronouncedly in warm seasons, an invasion of CO₂ was significant in this system. In terms of nitrogen budget, the annual nitrogen fixation exceeded the annual denitrification with a magnitude of 1.30 mol N m⁻² year⁻¹, which may be supported by the abundance of nitrogen fixation microplanktons in the lagoon.     

列控数据完备性建模方法研究

列控数据作为列车运行控制的基础,是列控系统的中枢神经,其完备性直接关系到列车运行安全.列控数据完备性能够保证列车安全控制数据的完整性、正确性、有序性、实时性、有序性和兼容性.本文以CTCS-3级列控系统和CTCS-2级列控系统之间的等级转换以及典型的设备故障导致降级场景为例,利用随机Petri网建立列控数据完备性模型,重点研究了列控数据完备性的完整性、实时性和兼容性方面的问题,最后提出了用模型完成的成功率以及系统平均延时时间分析列控数据完备性的方法.     

净现值与内含报酬率的比较分析

净现值和内含报酬率是资本投资决策采用的两个重要指标,两者之间通常具有一致性。但当两个投资方案为互斥方案时,时常会出现排序差异的情况。本文就两者关系做了比较分析,揭示出两者的根本区别在于基本假设不同,并提出实践中较为可行的决策方法。     

基于模糊神经网络的筑路机械生产率预测方法

以高等级公路沥青混凝土面层施工机械系统为研究对象，提出了一种施工机械生产率的预测方法，该方法利用神经网络和模糊数学，通过鉴定和收集相关数据，设计了带有模糊输入出系统的神经网络预测模型，该预测方法与现有的统计预测模型相比，使用更加简便，预测结果的准确性更高，该模型是针对沥青路面施工机械提出的，其建模的思想和方法对其他土木工程机械化施工系统也有一定的借鉴意义。     

基于.Net平台和Smart Client的高速公路公司信息管理系统

描述了一个基于Microsoft.Net平台和Smart Client架构的高速公路公司信息管理系统,用Web Service解决已有系统的数据层集成和业务逻辑的封装,同时,通过Smart Client为用户提供一个部署方便、管理集中,响应速度快、界面丰富和能脱网使用的应用程序,使整个系统更加实用和可靠.     

基于Petri网的地铁信号系统可靠性分析

地铁信号系统是地铁系统的中枢神经,同时也是提高地铁运营水平的重要保障。在分析信号系统功能及故障类型的基础上,划分了设备重要度水平。通过地铁信号系统Petri网5大对象子类框架的搭建,分析研究了信号系统重要设备发生故障的情况下,系统各子类的动态Petri网可靠性模型。     

混合动力汽车油耗测试试验研究

介绍非外接充电型HEV的能量油耗测试及数据分析结果。油耗与其主电池的充放电情况呈现很强的相关性,若某次试验的充放电净值为充电,且充电量大,则该车试验的油耗相对较高。通过充放电净值来修正油耗,可以得到该HEV的修正后油耗值。对修正步骤加以一定补充,可得出更接近真实值的油耗值。     

基于对称残差U型网络的路网交通流量数据修复

针对路网交通数据采集过程中，采集设备稀缺或故障等原因造成路网交通流量数据缺失问题，提出基于对称残差U型网络(Residual U-Net，RU-Net)模型的大规模路网交通流量数据修复方法.通过将路网交通流量数据网格化和时序通道化操作，构成可供卷积操作的张量数据格式；利用RU-Net编码解码能力，对交通流量数据进行编码；在解码过程中保持失真度较小，使模型学习到交通流量数据内部多因素耦合特性.通过残差学习使交通流量数据编码后的信噪比提升，压缩率降低，提升模型修复精度.实验结果表明，RU-Net模型能够利用交通流量特性学习历史和非故障采集点数据与待修复数据的映射关系，在不同数据缺失率，不同缺失模式下，高效地完成对大规模路网交通流量数据的修复.     

Transit technology investment and selection under urban population volatility: A real option perspective

This paper addresses transit technology investment issues under urban population volatility using a real option approach. Two important problems are investigated: which transit technology should be selected and when should it be introduced. A real option model is proposed to incorporate explicitly the effects of transit technology investment on urban spatial structure in terms of households’ residential location choices and housing market. The trigger population thresholds for investing in a transit technology project and for shifting from a transit technology to another are explored analytically. Comparative static analyses of the urban system and transit technology investment are also carried out. It was found that (i) transit technology investment can induce urban sprawl; (ii) ignoring the effects of transit technology investment on urban spatial equilibrium can lead to a late investment; and (iii) there is a significant difference in the trigger population thresholds for transit technology shift estimated by the net present value approach and the real option approach.