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31.
This paper focuses on the evaluation processes by which decisions regarding transportation alternatives can be assisted. A multidimensional approach usually called multiple criteria decision making is required to represent the complexity of transportation policy and systems. The multiple criteria decision making techniques can be divided into two groups. The first is based on a ranking scheme approach and the second on a mathematical programming approach. A multiple objective mathematical programming procedure known as Goal Programming is presented. The authors examined the use of that procedure in real transportation problems. The results suggest that multiple objective mathematical programming techniques in general do not appear to be appropriate in transportation policy analysis involving mutually exclusive alternatives. Their use can be limited to special cases in the private sector. 相似文献
32.
An adjoint 1-D model was used to determine vertical diffusivity coefficients from temperature profiles collected within a filament escaping from the Galician coast following an upwelling event. The optimisation scheme ended with relatively high diffusivity values within the thermocline (9×10−5 m2 s−1). Such high values are relevant for biogeochemical exchanges between surface and deep waters in stratified areas.The optimised values were several orders of magnitude higher than the bulk of diffusivity measurements recorded with a free-falling device; however, the optimisation solution was consistent with the arithmetic mean of the measurements in the thermocline (7.7×10−5 m2 s−1), giving more weight to the few largest values. Below the thermocline, the data assimilation method failed because of the three-dimensional nature of the advective field of the upwelling system. Ignoring this advective forcing in the model led to estimates that were two orders of magnitude too high.The results suggest that turbulent mixing is a random process where a few intense events determine the average mixing that drives the long-term evolution of the water column structure. This statistical property is very important when one wants to use instantaneous diffusivity measurements for modelling purposes. 相似文献
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大跨度连续刚构桥施工期截面应力测试与分析 总被引:1,自引:0,他引:1
广西布柳河大桥主桥为主跨235m、墩高97米、桥宽仅8.3米的特柔预应力混凝土连续刚构桥。文章结合主桥施工监控实践,介绍大跨高墩连续刚构桥施工期截面应力测试及数据分析的方法,为同类桥型施工提供参考。 相似文献
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36.
Ho-Jin?HwangEmail author Han-Min?Lee Soonhung?Han 《Journal of Marine Science and Technology》2004,9(4):182-189
The selection of marine equipment is a time-consuming process for a ship outfitting designer. The inefficiency originates from the paper-based exchange of design information between shipyards and equipment manufacturers. We propose a method to exchange equipment models for electronic commerce. Shipyard practices were investigated to find out how the outfitting CAD library is being used. We also surveyed international standards for the exchange of digital equipment models, and analyzed the macroparametric methodology. We propose a hybrid method to represent the geometric information using STEP AP203 or the macroparametric method. The nongeometric information is defined according to the Parts Library (PLIB) standard. We implement a pilot system and test it with a ship design data set. The equipment model proposed can be used in the design process with heterogeneous shipbuilding CAD systems. The equipment model can improve the design and purchase process in shipyards. 相似文献
37.
基于全球乘用车整备质量、燃油箱容积和燃油消耗量数据的统计分析,推算出"NEDC工况"下的续驶里程;再通过众测油耗的统计分析,推算出乘用车满油箱燃料的实际续驶里程范围;对乘用车的供油系统设计及电动乘用车的续驶里程对标燃油车提供依据。 相似文献
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本文论述了船用航行数据记录仪的发展趋势以及在未来的船舶建造规范优化、海事责任的评判和航行安全保障方面的作用 相似文献
39.
NTSC-A型制冷模拟器软件系统主要由上位机程序和PLC程序构成。在上位机程序中,详细阐述了制冷元件数学模型的建立、控制逻辑的设计以及控制界面的开发,这构成了功能完善、相对独立的桌面操作系统。PLC程序实现了数据通讯,并通过梯形图来完成相关的控制功能。培训效果显示,本系统功能完善、结构稳健,实时性、仿真性强,可以满足《STCW公约》的培训需要。 相似文献
40.
随着全球化进程的推进,制定一个国际通用的汽车行业质量管理体系认证标准已经成为广大汽车生产厂家的共同呼声,在此背景下,ISO/TS16949在1999年应运而生。经过适应性更改,2003年ISO/TS16949:2002正式发布并沿用至今。五大工具是ISO/TS16949:2002推荐的产品策划、过程控制、实现预防为主及其测量系统评定的重要手段,是集世界汽车制造企业专家管理经验之大成而总结的产品质量管理方法,其在企业生产经营的过程中表现出来的质量控制的有效性已经经过实践再三检验。五大工具之一——设计潜在失效模式及后果分析(DFMEA)是ISO/TS16949:2002推荐的实现预防为主的重要手段。应用DFMEA可以识别、评价产品设计中潜在的失效及其后果,找到能够避免或减少这些潜在失效发生的措施。将这些分析过程文件化,这是对设计过程的完善。成功实施DFMEA的重要因素之一是及时性,它是一个"事前的行为",而不是"事后的处置",为达到最佳效益,DFMEA必须在产品设计失效模式被纳入到产品设计之前进行。ISO/TS16949:2002中有大小15个条款涉及DFMEA,其质量控制思想贯穿于TS16949标准全过程。如何快速应用DFMEA工具,在汽车产品设计过程中有效的进行质量控制,成为各大汽车生产厂家应该重点关注的问题。 相似文献