基于时域差异关系的车辆电子稳定性控制系统判据

提出一种车辆电子稳定性控制系统(electronic stability control system,ESC)补充判据用于定性判定车辆平面运动过程中可能出现的后轴滑移工况.分别研究了二自由度侧向动力学系统方程与考虑纵向加速度因素的三自由度系统方程稳定性判定方法,考虑了车轴切向力与载荷变换对轮胎侧偏特性的综合影响.通过瞬态稳定性分析方法,得到了动力学系统稳定性变化和车辆实际稳定性变化之间可以量化的时域差异关系,基于这种时域差异关系建立了稳定性超前控制方案与理论模型,以理论模型在工况切换瞬态的系统平衡点特性作为控制判据,并且对现有ESC判据应对后轴滑移工况的有效作用时间进行评价.研究表明,特定工况下横摆角速度最大值定义的约束边界与车辆实际稳定性变化边界接近,ESC系统进行控制的时间差有限,超前控制判据理论上可以更早预测车辆运动状态变化.

论企业管理的地域差异及时域差异

新中国成立后,我国处于百废待兴的状态,为了赶上发达国家的脚步,不少中国企业家苦学西方的管理方法,却发现并不是每一种方法都适合中国的企业。这是因为中外在历史、文化、信仰等各个方面都有不小的差异,因此企业家必须意识到,企业管理是具有地域差异性的,此外,我国政府的经济政策也在不断地改变,因此企业管理还具有时域差异。本文将以我国知名企业为实例,分析企业管理的地域差异和时域差异,发现成功企业的企业管理往往具备"因地制宜"和"因时制宜"的特点。

一种3D残差神经网络视频行人动作分类改进方法

对于视频行人动作分类方法中,卷积神经网络模型对时域信息理解能力不足的问题,针对拥有深层的3D残差卷积神经网络提出一种联合计算方法,使深层特征的时域信息差异与损失差异共同参与模型的梯度下降过程,提升网络所学特征对时域信息的稳健表达,改进网络对时域信息的理解能力。经仿真实验证明,3DResNeXt-101网络在添加了联合计算方法后,对UCF-101和HMDB-51数据集的测试准确度都有不同程度的提升,网络模型的性能经由联合计算方法的辅助得到了增强。

SPATIAL-TEMPORAL CHANGES AND TRENDS OF AGEING IN CHINA

This study focuses on the development stages of ageing and its regional differences in China based on examination of official statistics and documents. The development of ageing in China has experienced three major stages. Firstly, in the 1950s, low coefficient of elderly population (over 65 years) paced up to primary adult type. Secondly, there was a deeply drop of the elderly population because of natural disaster and political factors in the 1960s. Thirdly, from the 1970s to the end of 20th century, the constant increasing of elderly coefficient made China close to elderly society. With statistic data of population, Logistic model is used to simulate the future development of ageing, and two characteristics of development of ageing are presented. Firstly, as for ageing from 2005 to 2050, the elderly coefficient will grow up significantly from 8.48% to 16.30%. Secondly, after 2025, the increasing rate of elderly coefficient will slow down gradually. The regional differences of elderly population in China can be summarized as follows: 1) the eastern China possesses higher elderly coefficient and huger elder population than the western China; 2) about 47.4% of municipalities and provinces in the eastern China become elderly especially Shanghai, Zhejiang Province, Jiangsu Province, Beijing, Tianjin and Shandong Province; 3) ageing intensity is higher in rural area than urban area but getting close each other, and there are more elderly people in rural area than in urban area. Therefore, these will arose aged care problems, and it becomes important issue to establish the social security system in rural areas as soon as possible for elderly people.

Calculation and application of full-wave airborne transient electromagnetic data in electromagnetic detection

Airborne electromagnetic transient method enjoys the advantages of high-efficiency and the high resolution of electromagnetic anomalies,especially suitable for mining detection around goaf areas and deep exploration of minerals.In this paper,we calculated the full-wave airborne transient electromagnetic data,according to the result of numerical research,the advantage of switch-off time response in electromagnetic detection was proofed via experiments.Firstly,based on the full-wave airborne transient electromagnetic system developed by Jilin University(JLU-ATEMI),we proposed a method to compute the full-waveform electromagnetic(EM)data of 3D model using the FDTD approach and convolution algorithm,and verify the calculation by the response of homogenous half-space.Then,through comparison of switch-off-time response and off-time response,we studied the effect of ramp time on anomaly detection.Finally,we arranged two experimental electromagnetic detection,the results indicated that the switch-off-time response can reveal the shallow target more effectively,and the full-waveform airborne electromagnetic system is an effective technique for shallow target detection.

Characteristics of diurnal variations of warm-season precipitation over Xinjiang Province in China

Aimed at improving knowledge regarding the diurnal cycle of warm-season rainfall in northwestern China,this study investigated the diurnal variations of warm-season precipitation with different durations in Xinjiang,China,using an hourly gauge–satellite merged precipitation product during 2008 to 2019.Results show noticeable diurnal variations with distinctive regional features.The primary peak is in the early evening.Rainfall events with duration less than 3 h occur more often across the whole of Xinjiang and contribute more than half of the precipitation amount over its northern and southern peripheries,while rainfall events with duration more than 7 h over the Tianshan Mountains are responsible for the primary peak in the diurnal variations of warm-season precipitation.

Region Pair Grey Difference Classifier for Face Detection

A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition between regions coinciding with the face pattern structure. Fifteen brighter and darker region pairs were chosen to form the region pair grey difference features with high discriminant capabilities. Instead of using both false acceptance rate and false rejection rate, the mutual information was used as a unified metric for evaluating the classifying performance. The parameters of specified positions, areas and grey difference bias for each single region pair feature were selected by an optimization processing aiming at maximizing the mutual information between the region pair feature and classifying distribution, respectively. An additional region-based feature depicting the correlation between global region grey intensity patterns was also proposed. Compared with the result of Viola-like approach using over 2 000 features, the proposed approach can achieve similar error rates with only 16 features and 1/6 implementation time on controlled illumination images.

The emergence, development and regional differences of mixed farming of rice and millet in the upper and middle Huai River Valley, China

Mixed farming of rice and millet is one of the basic agricultural modes in the upper and middle Huai River Valley(HRV). According to the latest data, this agricultural mode appeared during the middle and late Peiligang Culture(7.8–7.0 ka BP) in the upper HRV, and then became a common subsistence economy in the end of the Neolithic(5.0–4.0 ka BP) in both the upper and middle HRV. However, it is still not clear how this mixed farming developed in the upper HRV after its occurrence, nor are the regional differences in the development of mixed farming between the upper and middle HRV during the Neolithic completely understood. In this paper, flotation and starch analyses were conducted on samples from eight archaeological sites in the upper and middle HRV. The results indicate that the mixed farming of rice and millet first appeared in the later phase of the middle Neolithic in the regions of the Peiligang Culture, then developed quite rapidly in the late Neolithic(6.8–5.0 ka BP), finally becoming the main subsistence economy at the end of the Neolithic in the upper HRV. However, there are obvious differences in the emergence and development of agriculture between the middle and upper HRV. Rice farming was the only agricultural system during the middle Neolithic, lasting until the end of the Neolithic, when mixed farming appeared in the middle HRV. Furthermore, although mixed farming appeared in both the upper and middle HRV during the end of the Neolithic, the roles of rice, foxtail millet and broomcorn millet in the subsistence economy were not the same. In general, millet was more widely cultivated than rice in the upper HRV, but rice occupied the same or a slightly more prominent position in the middle HRV at the end of the Neolithic. These results are significant for understanding the process of agricultural development and transformation, as well as human adaptation to climatic and cultural variability duringthe Neolithic.