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本文基于“交通管理与控制”课程实践性、综合性强等特征,提出将VISSIM交通仿真软件运用于“交通管理与控制”课程教学中.通过一典型十字型交叉口的信号配时及仿真过程,介绍了软件在交通控制实验教学中的应用方法与步骤.对学生进一步巩固基本理论知识,深入理解交叉口的基本概念、作用有重要意义. 相似文献
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城市道路交叉口连续交通组织对于提高城市道路通行能力、缓解交通拥堵具有重要的作用。远引平面交叉口就是通过对交叉口直行车辆与左转弯车辆进行独特的交通渠化来实现连续交通组织的。通过对衡州大道苗圃路口进行U型远引式交叉改造,完全消除了冲突点,有效降低了主干道直行车辆的延误。 相似文献
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公路尤其是普通干线公路在引导城市发展、划定城市发展边界、推动完善城镇功能等方面发挥了至关重要的作用.本次研究主要在现代化群组型城市模式下,从各组团的发展阶段和规划定位解读入手,对各组团的交通需求特点逐一进行分析,确定干线公路过境城市的规划方案. 相似文献
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机组的实际负荷即实发功率是机组协调控制系统中的重要组成部分,现代大型发电机组一般都采用有功功率变送器来测量机组的实发功率,这无疑就给参与机组协调控制的有功功率变送器本身的质量、回路的可靠性和DCS逻辑的组成提出了更高的要求。本文介绍了几起由于有功功率变送器本身和回路故障而引起的异常事件,详述了为保证参与机组协调控制有功功率变送器的安全可靠运行,在其回路及DCS逻辑组成上所做的优化方案。 相似文献
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目前国内的电力需求仍然靠燃煤发电。燃煤电厂的经济高效运行是我国实现能源节约和节能减排的重要途径。燃煤电厂的锅炉运行调整,是通过改变燃烧量等参数,减少燃烧过程的热损失,以提高能源利用率。首先探讨了锅炉运行调整的意义和一般内容,然后分析了影响锅炉运行效率的主要因素。然后提出了锅炉运行调整和优化的一般方法和策略：通过运行调整减少锅炉内的燃烧损失、减少减温水量以及排污量等均是提高锅炉运行性能的可行方案。本文的研究和分析结果可以为实际运行中锅炉的运行调整提供一定的参考,为锅炉运行的优化提供一些可行的方案。 相似文献
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由于交通系统的复杂性和特殊性,目前的城市交通动态诱导主要基于对路段平均速度的检测.本文针对城市道路的特点,选取饱和度、平均速度、延误三个指标,运用状态分类分析的方法计算出三个指标综合下的各类交通状态的限值,为动态交通诱导系统提供数据支持. 相似文献
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分布式电源的选址与定容是一个重要的研究课题.本文以配电网的网络损耗费用和分布式电源的运行费用最小为优化目标建立了分布式电源的优化选址定容模型,应用遗传算法进行求解.通过实际算例表明,本文采用的优化模型有助于得到合理的分布式电源接入位置和容量方案. 相似文献
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陈静析 《上海体育学院学报》1986,(4)
方案创造法就是研究各种方案创造的方法和规律。方案的创造在控制系统中也有重要的作用。系统要优化控制,就应对两个以上的方案进行对比,新方案的提出要与原方案对比,在多种方案中也要进行优化对比的决策。方案创造法是更好地运用控制论方法的一个重要环节。方案创造法的实施,与系统方法也有密切联系。系统方法告诉我们,要完好地达到目标,应重视对目标的分解,又要强调系统内容等等之间联系和协调。方案创造法也同样运用系统信息、控制、反馈各种功能,并应重视分解、联系的特点。为了更深刻地理解创造原理,这里也 相似文献
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This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
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Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
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Alan M. Nevill Roger L. Holder Andrew Bardsley Helen Calvert Stephen Jones 《Journal of sports sciences》2013,31(4):437-443
A regression analysis of competitors' tournament results in relation to their world rankings was proposed to identify the effect of home advantage in international ‘grand-slam’ tennis and ‘major’ golf tournaments. The results provided little evidence of home advantage in either the grand-slam tennis or the golf tournaments held in 1993. The only possible evidence of home advantage was found in the Wimbledon tennis and the US Open golf championships. Even these findings can be explained, at least partially, by (1) the availability of information concerning the low world rankings of the British tennis players competing at Wimbledon, and (2) selective entry, allowing only the world's top-ranked foreign golfers into the US open golf tournament. In both cases, the lower ranking home competitors have a greater opportunity to perform above their anticipated world rankings. Therefore, provided entry into tennis and golf tournaments is truly ‘open’ to both the host nation's representatives and foreign competitors alike, home advantage does not appear to be a major factor influencing the competitors' performance in such competitions. These findings may be explained by the relatively objective nature of the scoring systems used in tennis and golf, unlike the subjective influence of refereeing decisions on the results of team-games such as soccer. 相似文献
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许良 《体育科技文献通报》2011,19(2):1-4
基于1985、1995和2005年全国学生体质调研数据,对各时期我国城乡学生形态、机能、体能发展水平进行系统地定量研究,动态分析20年全国城乡学生体质发展的特点与规律。主要研究结果：（1）近20年城乡学生生长发育持续提前,城市学生各项形态指标生长水平高于乡村,身高城乡差距缩小,体重、胸围城乡差距加大;（2）城市学生肺活量水平高于乡村,城乡学生肺活量20年持续下降,前10年乡村学生下降快、后10年城市学生下降快;（3）乡村学生800m、1000m跑水平高于城市,城市女生50m跑、仰卧起坐水平高于乡村,其他素质城乡学生水平波动较大;（4）城市女生50m跑20年持续下降,城乡学生800m和1000m跑、城市学生50m×8往返跑20年加速下降,其他素质20年间有增有降发展极不平稳。 相似文献
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采用测量、问卷调查、数理统计等方法,分析定向运动学习前后对大学生身心健康的影响.结果经T检验和x2检验且表明：定向运动不仅能增强学生体质健康水平,而且有助于学生的情绪调节,增强自信心与创新意识,培养勇敢顽强的意志品质,建立良好的人际关系,能有效地促进学生身心健康发展.为了全面提高大学生整体素质,积极实践,构建定向运动课内外一体化教学模式,进行定向运动课程模块化教学,以满足学生的多元化需求. 相似文献
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重新认识体育的社会关联 总被引：3，自引：1，他引：2
体育与政治之间存在一个悖论，体育的发展与经济实力之间没有直线相关，体育与教育部分重叠，体育与宗教最为近缘，体育可借用科学手段，体育的艺术禀性日益明显，体育与养生反映着两种人生观。 相似文献
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本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。 相似文献
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对全面把握游泳训练环节的探讨 总被引：4，自引：0，他引：4
从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。 相似文献