Open Park Transformation and Upgrading Means of Comprehensive Park: A Case Study of Xuzhou Quanshan Forest Park

The transformation and upgrading of comprehensive park can not be only limited to the adjustment for structure, function and landscape facility of comprehensive park itself, which shall be carried out as a whole. Viewing from the macroscopic perspective of city, comprehensive park is an important constituent part of urban green space system, and its transformation is an integral part of overall perfection and development of urban green space system. Park is an organic integrity comprising many elements. The transformation of comprehensive park shall be carried out as a whole and handled by using the methods of "from top to bottom" and "from bottom to top", thus adjusting the relationship between park and city and within park on the whole. This research takes the open park transformation and upgrading of Xuzhou Quanshan Forest Park as an example to introduce the key points of open park transformation from such aspects as of entrance space, overall space structure, service function expansion and spatial form optimization in expectation of having a certain reference value.

Research on Transformation of Operation Mode of Shenzhen International Landscape Flowers Exposition Park in China

After a brief review of construction and usage history of Shenzhen International Landscape Flowers Exposition Park,the paper had analyzed its operation mode and benefit perceptively during exhibition period and the period after exhibition before successful transformation.Based on relevant data,it could be known that the operation of exposition park had been reduced into a plight after exposition finished,and it revealed the necessity and urgency for transformation of operation mode.It has introduced in detail the transformation progress of three stages covering adjustment of operation,enterprises trusteeship and cooperation demonstration,and free open throughout more than 2 years.It had analyzed the reason why expected benefit hadn't been achieved,and emphasized that the operation mode of the park should be with maximization of social benefit as the target and free open as the transformation form.It had been proved that free open could not only increase tourist capacity and obtain great social benefit,but also increase indirect economic income;finally change the vicious circle of operation plight.On this basis,characteristics of comprehensive park of exposition type had been concluded,so as to provide technical support and reference for holding horticultural exposition,launching construction and operation of comprehensive park of exposition type,and establishing national key park in the future.

Exploring the “Green” Transformation Planning of Industrial Parks in the Era of Low Carbon Economy

The core function of the low carbon economy is to change the economic development trend of the whole society. It is necessary to carry out industrial transformation and upgrading according to the concept of sustainable development and to realize integrated technological innovation and efficient economic development without violating the law of ecological and environmental development. In the era of the low-carbon economy, industrial parks should solidly promote the green transformation planning process. Relying on the basic logical framework of green transformation of industrial parks, it can build a green development quality evaluation system of industrial parks and formulate a green planning mechanism and green economic cycle development model in line with the background of the low-carbon economy.

Strategies for multi-step-ahead available parking spaces forecasting based on wavelet transform

A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies.

基于CNN-Transformer的自动泊车车位感知算法

为提高自动泊车成功率及准确性,首先基于卷积神经网络(CNN)模型对输入图像进行特征提取,然后利用Transfomer模型的“编码-解码”机制对CNN提取到的图像特征平铺后进行计算推理,通过前馈神经网络得到目标预测结果,最后基于180°广角鱼眼图像进行推理识别,车位角中心点和空车位入口中心点均采用二维坐标表示,降低了输出信息的冗余,优化了模型结构。测试结果表明,该算法能够较好地适应不同车位线划线方式和不同的自然环境,目标感知的召回率达到98%,车位角中心点定位平均误差小于3 cm,满足泊车系统对车位感知的鲁棒性、实时性和准确性要求。

基于PARK变换的空间矢量调制矩阵变换器在非理想条件下的稳态分析

将ＰＡＲＫ变换引入到空间矢量调制的矩阵变换器中，建立了矩阵变换器的线性时不变电路模型。借助电路分析理论，分析了空间矢量调制矩阵变换器在某些非理想条件下稳态特性，得出了有关特性的解析表达式。仿真结果及理论分析表明这种等效电路具有一定的实用性。

基于PARK变换的空间矢量调制矩阵变换器的暂态分析

将PARK变换引入到空间矢量调制矩阵变换器中 ,建立了矩阵变换器的线性定常电路模型。借助电路分析理论 ,分析了空间矢量调制矩阵变换器的暂态响应特性与输入滤波器参数的关系。

基于Park变换的改进谐波分析算法

基于同步旋转坐标系理论,介绍一种改进的Park变换方法来检算谐波电流。该方法不受电网电压畸变影响,理论上可以检测任意次谐波的正序、负序、以及基波电流的有功和无功分量,从而实现对负载电流成分的完全分解。应用此方法仿真,对已知谐波分量的数据进行分析,并以有源滤波器在典型应用环境——二极管整流电路负载情况下进行系统仿真。仿真结果与理论分析相符,表明了该方法的可行性。

用Park变换方法检测感应电动机转子故障

通过Park变换方法,利用感应电动机定子电流在dq坐标系中是一个“畸变圆”还是一个圆,来判断鼠笼转子有无故障,提出了一种感应电动机转子故障检测的新方法,并定义了与故障严重程度相关的“畸变圆”的畸变率。用数字仿真和实测结果验证了该方法的有效性,并给出了导条断裂根数和畸变率之间的关系式,以判断感应电动机鼠笼转子故障的严重程度。

基于Park变换的配电网多端行波故障定位方法

单端和双端行波定位方法都很难准确定位配电网故障,因此提出一种采用多端行波的配电网故障定位方法.首先给出基于Park变换的自适应行波检测策略,在分析双端行波定位缺陷的基础上,根据检测到的行波到达各配电线路末端的时间,给出多端行波故障定位的原理.该方法克服了由于配电线路结构复杂所造成的反射波识别困难,而且不受故障类型、故障初始相角和接地电阻大小的影响.采用PSCAD/EMTDC仿真软件和MATLAB软件对不同的故障工况进行仿真,仿真结果表明,本文方法能够快速准确地定位故障点,从而证实了该方法的有效性和可靠性.

正交Park变换在同步电机分析中的应用

通过正交变换的方法,推演出基于正交变换的dq0坐标系同步电机的基本方程,证明了方程变换前后电磁功率是“守恒”的,电感系数矩阵也具有互易性。对基于正交变换的dq0坐标系同步电机方程标幺值形式进行了推导,推导出各电感系数的基准值。

三相电路瞬时电流、功率的分解与Park空间分析

用三种方法讨论了三相电路中瞬时电流和功率的分解和定义 ,阐述了这三种方法的相互联系 ,说明了各分量的物理意义和在矩阵

Park矢量变换在异步电机故障诊断中的应用

分析了异步电机系统中Park变换过程,应用矢量变换将三相定子电流转换为图形方式进行故障诊断,文中给出了故障形式与图形的关系,通过实例验证了该方法的有效性。

基于Park变换的感应电机故障诊断

提取定子电流信号的Park矢量图作为电机故障特征,应用人工神经网络技术对故障特征进行分类与识别,从而避开复杂的谱分析技术,实验测试结果表明,该方法用于电机故障诊断可靠、有效,是一种实际可行的电机故障诊断方法。

基于Park变换的单相光伏并网控制研究

近年来,LCL滤波器由于体积小、滤波效果好等优点在光伏并网系统中获得了广泛应用。采用并网电流、电容电流双闭环控制能够有效抑制LCL滤波器振荡,提高并网系统稳定性,但传统PI控制无法实现对交流并网电流的无静差跟踪。因此,提出了一种基于Park变换的双电流闭环控制策略,它能够大大提高并网功率因数,减小入网电流的总谐波失真(THD)。该方法首先通过构造虚拟正交电流分量,将单相并网电流虚拟为α-β坐标系下两相正交电流,然后基于Park变换,在旋转坐标系下进行PI控制,从而实现无静差控制。最后,通过Matlab仿真验证了这种控制策略的正确性和有效性。

基于Park变换的UPQC检测方法研究

介绍了一种综合型的电能质量补偿装置UPQC的功能和结构,分析了它的检测方法与单独的串、并联有源滤波器的不同之处。在此基础上,提出利用瞬时无功功率理论中的Park变换法,分别提取三相不对称及畸变电压系统中基波正序的幅值和相角,并让电源参考电流跟踪基波正序电压的检测方法。该方法与现有的UPQC检测方法相比,简单易行,实时性好,避免了大量的相量计算,且无须对三相不对称及畸变电压进行锁相和滤波。仿真结果验证了这种方法的正确性。

基于反Park变换的不平衡锁相环设计研究

为实现不平衡电网下正序基波电压相位和幅值的快速、准确获取,文中提出一种基于反Park变换的三相锁相环设计方案。提出一种基于反Park变换的正交信号发生器实现方案;对前述方案进行了详细的数学分析,从理论上证明了所提方案可以有效进行信号正交处理,并给出其关键参数的设计方法;接着,以该正交信号发生器为基础,构建适用于电网不平衡条件下的三相锁相环;通过搭建PSCAD仿真模型在多种电网环境下对文中所设计锁相环进行性能测试,仿真结果表明该锁相环具有良好的适应性,能快速、准确地锁定正序基波电压的相位和幅值。

基于Park变换的三相交流电相序判断研究

本文首先对Park变换原理进行阐述,然后在Park变换原理的基础上提出一种新的相序判断的方法。论述了三相交流电相序判断方法的原理和实现算法,并通过软件仿真的方式验证了该方法的正确性、可靠性和实时性。

基于Park变换和Teager能量算子的晶闸管逆变器保护新方法

在高压直流输电系统中,晶闸管逆变器直流差动保护误动于区外故障,以晶闸管逆变器作为研究对象,提出了基于Park变换和Teager能量算子的晶闸管逆变器保护新方法。首先,利用Park变换分析逆变器交流侧电流,建立和直流侧电流的平衡关系,提出主判据;其次,采用逆变器交流侧接地故障的零序电流和逆变器交流侧电流的Teager能量算子作为辅助判据;最后,通过PSCAD仿真将该保护和传统直流差动保护进行比较。结果表明:该保护可有效解决传统直流差动保护误动于区外故障的问题,对于直流差动保护不能动作区内的相间短路故障,该保护方法可正确动作。

三相非平衡系统park变换的理论分析

在电力系统分析和计算中,park变换具有重要的理论和实际意义,直接从三相非平衡系统出发,借助通用相量的概念,通过坐标变换,从理论上得出了三相非平衡系统的park变换.