空气质量响应曲面模型在杭州市的应用     

戴志翔  胡诗玮  罗坤  高翔  樊建人  岑可法 《中国科学院大学学报》2017,34(2):179-185

基于CMAQ模拟结果，统计、归纳出各种污染物排放控制因子与污染物浓度之间的函数关系，建立空气质量响应曲面模型RSM，通过留一法交叉验证和外部验证对模型进行可靠性验证。使用RSM，研究不同污染物的PM_2.5响应值，评估现有政策不变（Ⅰ）和政策收紧（Ⅱ）两种减排情景，发现NO_X、SO₂、NH₃和VOC对PM_2.5浓度体现明显的非线性响应特征，情景Ⅱ的减排效果明显好于情景Ⅰ，夏季的减排效果好于冬季。  相似文献   

增程式混合动力集装箱龙门起重机能量智能控制策略     

刘海威  张敏 《上海海事大学学报》2016,37(2):77-82

针对集装箱龙门起重机的具体工况需求和特点，构建一种适用于集装箱龙门起重机的增程式混合动力系统，提出并分析该动力系统的能量智能控制策略，设计相应的智能控制模型.通过以动力电池组的荷电状态（State Of Charge, SOC）和集装箱龙门起重机运行能量需求为模糊输入，以动力电池组的充电功率为模糊输出，实现了对增程式混合动力系统的智能控制.仿真结果验证了该控制策略和控制模型的可行性和有效性.  相似文献   

Quiet eye training aids the long-term learning of throwing and catching in children: Preliminary evidence for a predictive control strategy     

C. A. L. Miles  S. J. Vine  J. N. Vickers  M. R. Wilson 《European Journal of Sport Science》2017,17(1):100-108

Abstract

Quiet eye training (QET) may be a more effective method for teaching children to catch than traditional training (TT) methods, but it is unclear if the benefits accrued persist in the long term. Thirty children were randomly allocated into a QET or TT group and, while wearing a mobile eye tracker, underwent baseline testing, training and two retention tests over a period of eight weeks, using a validated throw and catch task. During training, movement-related information was provided to both groups, while the QET group received additional instruction to increase the duration of their targeting fixation (QE1) on the wall prior to the throw, and pursuit tracking (QE2) period on the ball prior to catching. In both immediate (R1) and delayed (R2, six weeks later) retention tests, the QET group had a significantly longer QE1 duration and an earlier and longer QE2 duration, compared to the TT group, who revealed no improvements. A performance advantage was also found for the QET compared to the TT group at both R1 and R2, revealing the relatively robust nature of the visuomotor alterations. Regression analyses suggested that only the duration of QE1 predicted variance in catch success post-training, pointing to the importance of a pre-programming visuomotor strategy for successful throw and catch performance.  相似文献   

Performing under pressure: Exploring the psychological state underlying clutch performance in sport     

Christian Swann  Lee Crust  Patricia Jackman  Stewart A. Vella  Mark S. Allen  Richard Keegan 《Journal of sports sciences》2017,35(23):2272-2280

Clutch performance is improved performance under pressure. However, little research has examined the psychological state experienced by athletes in these situations. Therefore, this study qualitatively examined the subjective experience underlying clutch performance across a range of sports (e.g., team, individual) and standards (Olympic to recreational athletes). Sixteen athletes (M_age = 27.08 years; SD = 6.48) took part in in-depth, semi-structured interviews primarily after an exceptional performance (M = 4.38 days later; SD = 3.14). Data were analysed inductively and thematically. Clutch states involved 12 characteristics, including heightened and deliberate concentration, intense effort, and heightened awareness, which distinguished the experience of clutch from other optimal psychological states such as flow. Other characteristics, such as perceptions of control, were also reported and supported previous experimental research on clutch. These findings present in-depth qualitative insights into the psychological state underlying clutch performance, and are discussed in relation to the existing literature on optimal psychological states in sport.  相似文献   

基于相对全变分的复杂背景SAR图像舰船尾迹检测     

杨国铮  禹晶  孙卫东 《中国科学院大学学报》2017,34(6):734-742

SAR图像舰船尾迹检测不仅能够反演运动舰船的航速航向信息，也有助于发现图像中弱小的舰船目标。现有的舰船尾迹检测方法对于简单背景SAR图像的检测效果较好，但复杂背景下的检测效果难以满足使用要求。提出一种基于能量泛函极小化的复杂背景SAR图像舰船尾迹检测方法。该方法采用相对全变分技术将图像分解为包含舰船尾迹的光滑成分和海背景纹理成分，通过剪切波变换高频系数重构增强光滑成分，再通过Radon变换检测光滑成分中的尾迹线。比对实验结果表明，本文所提方法对于复杂背景SAR图像的舰船尾迹检测效果明显优于现有的方法。  相似文献   

基于VxWorks的微小型AUV体系结构设计     

聂建多  褚振忠  朱大奇 《上海海事大学学报》2016,37(3):90-94

为提高自主式水下机器人(Autonomous Underwater Vehicle,AUV)控制系统的鲁棒性，将分层递阶结构与包容式结构相结合，提出了一种混合式控制体系结构，开发了基于VxWorks的微小型AUV控制系统.该系统以“海事金枪鱼”号AUV为载体，以嵌入式PC104计算机为系统核心,通过传感器的信息融合、算法实现和多任务运行，控制系统驱动推进器、舵、翼等执行单元实现AUV的姿态调整、导航和路径规划，最终达到自主作业的目的.“海事金枪鱼”号AUV的开发应用，验证了方案的可行性以及控制系统的可靠性和稳定性.  相似文献   

基于船舶航行仿真的吴淞口建闸方案优化     

曹圆圆  白响恩  肖英杰  杨小军  郑剑 《上海海事大学学报》2016,37(1):55-59

为评价吴淞口3个建闸方案的可行性，提出一种基于船舶航行仿真的建闸方案选优方法.通过观测和分析黄浦江交通流情况，选出恰当的代表船型并搜集代表船型的船舶资料建立船舶操纵模型，制作电子海图.根据水文气象信息设计各仿真试验方案，在考虑船舶习惯航法的基础上进行单船及大小船交会的仿真试验；分析重要指标，如航道宽度、转向角等，确定推荐方案并在此基础上进行优化.该方法能为吴淞口建闸方案的确定提供科学依据，可作为评价比选建闸方案的有效新途径.  相似文献   

一种在轨海上多运动舰船目标检测和跟踪方法     

矫腾章  胡玉新  吕鹏  张凯  台宪青 《中国科学院大学学报》2020,37(3):368-378

传统遥感卫星图像处理采用在地面进行目标检测和跟踪处理的模式，卫星将拍摄到的图像数据下传至地面数据处理中心，由地面数据处理系统对接收到的遥感图像数据进行目标检测和跟踪。然而，随着遥感图像分辨率的不断提高，需要下传的数据量增大，导致星地数据传输的时间大大增加，最终造成目标检测和跟踪的时效性降低。针对上述问题，提出一种基于多特征量判别的Canny边缘检测和联合概率数据关联的在轨海上多运动舰船目标检测和跟踪方法。将该方法利用中国科学院微小卫星创新研究院的高分微纳卫星实测数据在模拟星载的嵌入式开发平台上进行验证，结果表明该方法能够在轨对海上多运动舰船目标进行快速、准确的检测和跟踪。  相似文献   

长江口深水航道船舶超宽交会通航效率分析     

周伟  肖英杰  郑剑 《上海海事大学学报》2019,40(2):1-5

为提高长江口深水航道通过能力,减少由船舶交会宽度限制产生的延误,通过分析船舶超宽交会现状,建立仿真逻辑模型,运用Arena进行离散仿真试验。采集长江口深水航道交通流数据,设置不同的船舶交会宽度限制,对大型船舶进出港过程进行仿真,分析不同交会宽度限制对船舶通航的影响,获得被延误船舶比例、被延误船舶数量和延误时间,进而提出提升通过能力的建议。试验表明,采用Arena进行离散仿真能够量化分析超宽交会对通航效率的影响,可为航道拓宽和交通管理提供科学依据。  相似文献   

Socioeconomic segregation between and within curriculum tracking     

《International Journal of Educational Development》2021

Previous studies have documented social segregation for single types of tracking, but little previous research has compared levels of segregation across different institutional tracking arrangements. This paper uses extensive administrative data of the Chilean educational system to estimate the magnitude and evolution of socioeconomic segregation between- and within-school curriculum tracking. Results indicate that the unequal distribution of students by socioeconomic status between tracks narrows when tracking takes place within schools, mainly in the presence of market incentives that lead schools to focus on particular student populations.  相似文献