Dynamic Equivalent Method of Motor Loads for Power Systems Based on the Weighted

Dynamic equivalence can not only largely reduce the system size and the computation time but also stress the dominant features of the system [1]-[3]. This paper firstly recommends the basic concept of dynamic equivalent and the status of both domestic and abroad development in this area. The most existing equivalent methods usually only deal with static load models and neglect the dynamic characteristics of loads such as induction motors. In addition, the existing polymerization method which is based on the frequency domain algorithm of induction electric machines parameters takes a long time to equivalent for the large system, then the new method based on the weighted is proposed. Then, the basic steps for dynamic equivalence with the weighted method are introduced as follows. At first, the clustering criterion of motor loads based on time domain simulation is given. The motors with similar dynamic characteristics are classified into one group. Then, the simplication of the buses of motors in same group and network is carried out. Finally, parameters of the equivalent motor are calculated and the equivalent system is thus obtained based on the weighted. This aggregation method is applied to the simple distribution system of 4 generators. Simulation results show that the method can quickly obtain polymerization parameters of generator groups and the aggregation model retains the dynamic performance of the original model with good accuracy, the active and reactive power fitting error is smaller as well.

Tide forecasting method based on dynamic weight distribution for operational evaluation

Through analysis of operational evaluation factors for tide forecasting, the relationship between the evaluation factors and the weights of forecasters was examined. A tide forecasting method based on dynamic weight distribution for operational evaluation was developed, and multiple-forecaster synchronous forecasting was realized while avoiding the instability cased by only one forecaster. Weights were distributed to the forecasters according to each one＇s forecast precision. An evaluation criterion for the professional level of the forecasters was also built. The eligibility rates of forecast results demonstrate the skill of the forecasters and the stability of their forecasts. With the developed tide forecasting method, the precision and reasonableness of tide forecasting are improved. The application of the present method to tide forecasting at the Huangpu Park tidal station demonstrates the validity of the method.

Statistical landslide susceptibility assessment in a dynamic environment:A case study for Lanzhou City,Gansu Province,NW China

This study presents a statistical landslide susceptibility assessment(LSA) in a dynamic environment. The study area is located in the eastern part of Lanzhou, NW China. The Lanzhou area has exhibited rapid urbanization rates over the past decade associated with greening, continuous land use change, and geomorphic reshaping activities. To consider the dynamics of the environment in the LSA, multitemporal data for landslide inventories and the corresponding causal factors were collected. The weights of evidence(Wof E) method was used to perform the LSA. Three time stamps, i.e., 2000, 2012, and 2016, were selected to assess the state of landslide susceptibility over time. The results show a clear evolution of the landslide susceptibility patterns that was mainly governed by anthropogenic activities directed toward generating safer building grounds for civil infrastructure. The low and very low susceptibility areas increased by approximately 10% between 2000 and 2016. At the same time, areas of medium, high and very high susceptibility zones decreased proportionally. Based on the results, an approach to design the statistical LSA under dynamic conditions is proposed, the issues and limitations of this approach are also discussed. The study shows that under dynamic conditions, the requirements for data quantity and quality increase significantly. A dynamic environment requires greater effort to estimate the causal relations between the landslides and controlling factors as well as for model validation.

Analysis of dynamic stress intensity factors of three-point bend specimen containing crack

A new formula is obtained to calculate dynamic stress intensity factors of the three-point bending specimen containing a single edge crack in this study. Firstly, the weight function for three-point bending specimen containing a single edge crack is derived from a general weight function form and two reference stress intensity factors, the coefficients of the weight function are given. Secondly, the history and distribution of dynamic stresses in uncracked three-point bending specimen are derived based on the vibration theory. Finally~ the dynamic stress intensity factors equations for three-pointing specimen with a single edge crack subjected to impact loadings are obtained by the weight function method. The obtained formula is verified by the comparison with the numerical results of the finite element method （FEM）. Good agreements have been achieved. The law of dynamic stress intensity factors of the three-point bending specimen under impact loadings varing with crack depths and loading rates is studied.

不同曲线半径下轨底坡与轮径差最佳匹配研究

为了研究不同曲线半径下地铁车辆动力学性能最优的轨底坡与轮径差最佳匹配,运用SIMPACK软件建立了地铁车辆动力学仿真模型,设置9种轨底坡工况和5种轮径差工况,以轮轨横向力、轮对横移量、脱轨系数、轮重减载率和轮轨磨耗指数作为车辆动力学性能的评价指标,以4种不同C型曲线半径作为研究对象,分析45种轨底坡和轮径差耦合工况下各指标的变化规律。采用熵权法对各指标进行加权求和处理,得到不同工况下的车辆动力学性能综合得分,最终分析得出车辆在不同半径曲线下轨底坡和轮径差的最佳匹配。研究结果表明:在300,400,500,600 m这4种曲线半径下,外轨轨底坡、内轨轨底坡和轮径差最优匹配方案分别为(1/20,1/40,+1),(1/20,1/40,+1),(1/30,1/30,-1),(1/40,1/30,-1)。

Optimal Thrust Allocation Logic Design of Dynamic Positioning with Pseudo-Inverse Method

This article presents a method named pseudo-inverse to solve the optimal thrust allocation of dynamic positioning (DP) system,proposes to optimally determine the azimuth angle of thrusters instead of man-control or semi-auto control,and combines with the pseudo-inverse methods to get the optimal solutions for dynamic positioning control system.It is able to greatly reduce the risk of manual mode.Three different kinds of modes are proposed and detailedly illuminated,and can be used to solve much more complex nonlinear constraint problems,such as typical forbidden vector boundary.Several illustrative examples are provided to demonstrate the effectiveness and correctness of the proposed thrust allocation modes.

场地污染地下水抽出处理系统井群加权优化方法研究

井群布设是地下水修复抽出处理技术的关键环节之一。为提高抽出处理技术的修复效率,以某污染场为研究对象,建立非线性-动态-多目标的模拟-优化模型,以污染物去除率最高、修复达标时间最短、资金成本最低为优化目标,设定单井、双井、三井模式下不同的抽出流量,采用加权优化方法对井群布设方案进行对比计算。结果表明:整体而言单井模式修复效果较差,侧重资金成本时双井模式抽出方案修复效果整体较优,侧重达标时间成本时三井模式抽出方案修复效果整体较优;单井模式恒定流量抽出修复效果较优,多井模式下后期若适当降低抽出流量,可减少总抽出量,节省资金成本,井群动态管理可提高修复效率。研究验证了加权优化方法在井群优化应用中的灵活性和实用性,可为加权优化方法结合数值模拟方法在抽出处理技术的井群布设优化中应用提供参考。

区域海事事故治理效果动态综合评价

为准确评价区域海事事故治理效果,通过构建动态综合评价模型,为水上交通安全规划提供决策依据。首先,从事故的绝对指标与相对指标角度出发,建立包含8个指标的区域海事事故治理效果评价指标体系。其次,使用博弈赋权法对熵权法所得权重和指标相关性权重确定法(Criteria Importance Through Intercriteria Correlation, CRITIC)所得权重进行组合,以确定各时段评价指标组合权重,并采用逼近理想解排序法(Technique for Order Preference by Similarity to Ideal Solution, TOPSIS)对各地区海事事故治理效果进行各时段静态综合评价。再次,通过混合时序算子集结各时段静态综合评价值,求得各地区海事事故治理效果的动态综合评价值,进而判断各地区海事事故的治理效果。最后,运用所建评价模型对2017—2021年上海、浙江、广东和山东4个地区海事事故治理效果进行动态综合评价。研究结果显示:与单一赋权TOPSIS法相比,博弈赋权-TOPSIS法所得静态综合评价结果更为合理可靠;与单一时序算子相比,混合时序算子所得动态综合评价结果更为合理可靠;随着海事事故治理策略和治理强度不同,上海和广东地区海事事故治理效果呈上升趋势,而浙江和山东地区海事事故治理效果呈下降趋势;广东地区海事事故治理效果稳定性最强,而浙江地区海事事故治理效果稳定性最弱;上海地区海事事故治理效果最好,而浙江地区海事事故治理效果最差。

中国共同富裕的测度、区域差异及动态演化

为扎实推动共同富裕取得实质性进展,全面反映共同富裕建设成效,本文探索共同富裕的量化体系。基于熵值法、Dagum基尼系数以及Markov链等实证分析方法,本研究从共同、共享和富裕3个维度测度中国共同富裕指数,并探索其时空演化规律。研究发现:①从区域层面看,共同富裕水平由高到低排序依次为东部、东北部、中部、西部。其中,北京、天津、上海和江苏位于高共同程度–高富裕程度区域。虽然共同程度指数下降,但共享程度指数和富裕程度指数的正向驱动效应更大,共同富裕指数呈现稳步上升趋势。②共同富裕的总体差异主要来源地区间差距,地区内差异贡献相对较小。区域内和区域间的共同富裕发展差距逐渐缩小。③共同富裕发展较为稳定,不同地区的共同富裕发展存在稳定性差异,一般不会出现跨越层级的跃升。临近类型转移的概率大于非临近类型转移的概率,上升转移类型的概率大于下降转移类型的概率。

考虑需求响应优先级的配电终端虚拟电厂优化调度研究

虚拟电厂技术提升了分布式能源消纳潜力、填补了电网调度盲区。为引导用户参与电力调度,在激励型需求响应购电协议基础上,构建了包含智能家居负荷和冷热联供建筑相变储能系统的虚拟储能模型,并量化分析各类资源可调度裕度;以用户响应特性为指标,采用熵权法评估各类用户负荷的动态响应性能,设置虚拟储能参与调度的动态响应优先级;以虚拟电厂收益最大为目标,综合考虑资源购电成本、电热平衡等因素,提出了集分布式电源和智慧社区激励响应负荷的终端虚拟电厂优化调度模型,采用改进光线寻优算法对模型求解。结果验证了所提方法的有效性。

考虑跨洋特征及碎冰对快速性影响的极地探险邮轮型线优化

[目的]全球减碳背景下,为应对极地船舶设计建造的环保要求,需开展跨洋航行时碎冰水域对极地探险邮轮船体型线优化设计的影响规律研究,以获得最佳节能型线。[方法]针对极地探险邮轮的跨洋航行特征,采用航区权重方法进行量化评估,分析碎冰对阻力和推进效率的影响。应用计算流体力学耦合离散元法(CFD-DEM)来分析螺旋桨的碎冰水域性能,建立以联合自航功率为目标的优化模型,进而对全船参数化模型开展设计航速下的优化计算。[结果]计算结果表明,优化后的船型可以满足排水量要求,有效降低了2种水域下的航行功率,其联合自航功率降低了9.71%。[结论]研究成果验证了基于权重优化方法的可行性和合理性,可为极地探险邮轮的型线和推进器优化设计提供参考。

一种基于宽带网格小区质量的动态评价方法

基于影响客户感知的主观KQI数据和客观网络KPI数据,建立多层次多维度的基于网格小区用户的动态评价体系。通过影响度基础因子、敏感因子、持续恶化因子等指标因子,区分场景和用户画像动态调整评估指标,应用熵值法计算各维度中指标的权重,引入变权函数动态调整初始权重,最后通过TOPSIS综合评估法,兼顾各维度对整体评价不同的影响程度,归一化后得出网格小区的综合评价得分。实际使用效果的统计数据验证表明,动态评价算法能够较好地反映网格小区用户的实际使用感知。

1-苯基-3-(1-环己胺)-丙烯Schiff碱缓蚀剂在盐酸溶液中对J55钢的缓蚀效果

为改善酸化压裂施工造成的腐蚀问题,以肉桂醛和环己胺为原料合成了Schiff碱酸化缓蚀剂1-苯基-3-(1-环己胺)-丙烯(PCP),通过红外光谱和气相色谱-质谱联用对其结构进行表征,并采用失重法、电化学(极化曲线、阻抗谱、噪声)及分子动力学模拟等方法评价了PCP的缓蚀效果。结果表明,合成产物即为目标产物PCP。在15%HCl、90℃的条件下,随着PCP浓度增加,J55钢的失重腐蚀速率及腐蚀电流密度显著减小,缓释率逐渐增大。不同PCP加量下的缓释率均可达到99%以上,缓蚀效果较好。在PCP加量达到0.15%时,腐蚀速率及缓释率随着缓蚀剂浓度的增加整体变化不大,即缓蚀剂在J55钢表面的吸附浓度已达到临界胶束浓度,吸附量不再发生变化。PCP同时抑制了阴极析氢和阳极溶解反应,为混合型缓蚀剂。随着PCP浓度的增加,容抗弧半径、极化电阻及噪声电阻由小到大的排序均为:空白﹤0.05%﹤0.10%﹤0.15%﹤0.20%;低频的白噪声水平在电流PSD图中随着PCP浓度的增加而减小,即J55钢的腐蚀速率不断减小,与失重法及极化曲线反应的规律一致。当PCP分子与金属发生吸附并达到平衡时,整个缓蚀剂分子处于同一平面,平行吸附在J55钢表面,达到完全覆盖,从而有效减缓了腐蚀介质的侵入。

基于动态组合赋权云模型的弧形钢闸门安全性评价

闸门的安全性评估是闸科学管理的关键环节。鉴于传统单一评估方法赋权存在的局限性,综合考虑闸门安装质量、启闭力、腐蚀程度等安全性评价指标,针对某些评价指标具有不确定性和模糊性的特点,引入动态组合赋权算法,重点考虑时间推移下弧形钢闸门各评价指标权重的变化,利用三标度法与熵值法得到组合权重,最终实现评价指标权重的主、客观与动静相结合,构建了基于动态组合赋权的弧形钢闸门安全性云评价模型。工程应用结果表明:所建立的评价模型不仅能定量且直观地反映弧形钢闸门安全性评价结果等级,而且能体现评价等级的时间推移规律,使得评价结果更符合实际情况,可以更好地反映钢闸门的运行情况。

中国式现代化时空分异特征与驱动因素分析

本文从经济现代化、社会文明现代化、科技与治理能力现代化、生态文明现代化4个维度出发构建中国式现代化指标体系,利用2012~2022年我国31个省(区、市)面板数据通过熵权法计算现代化的发展水平并探究其时序演变特征;并对4个子维度进行耦合协调分析,探究4个子系统的协调发展度的动态演进过程;最后通过空间计量分析方法探究中国式现代化的影响因素。研究发现:我国整体的现代化子系统协调发展水平较低,但协调发展度呈逐渐上升趋势;我国现代化水平呈现波动上升趋势,形成“东高西低”的格局,现代化水平整体存在较为明显的空间聚集现象;良好的经济发展水平、经济包容性政府调控能力以及人口增速、合理的产业结构及资源效率均能促进现代化水平的提升。

中国新质生产力水平测度、区域差异分解及动态演进

随着新一轮科技革命和产业变革的深入发展,新质生产力作为推动经济社会高质量发展的关键力量,其在我国各地区的水平和差异状况对于制定科学的区域发展战略具有重要意义。本文通过熵权-TOPSIS法对我国30个省(区、市)2012~2022年的新质生产力水平进行了测度,并分析了其区域差异及其动态演进。研究发现,中国新质生产力水平总体呈现上升趋势,但区域间发展不平衡,东部地区显著高于其他地区。基尼系数分解结果显示,区域间差异是造成整体不平衡的主要原因。本文还采用核密度估计方法分析了新质生产力水平的空间演变特征,发现区域间生产力水平差异正在缩小,表明我国在促进区域均衡发展方面取得了积极进展。为进一步促进新质生产力的均衡发展,本文提出了加强科技创新支持、深化体制机制改革、实施差异化区域发展战略、注重人才培养和完善基础设施建设等政策建议。

基于多目标优化模型的扇叶最优分组与排列方案

衡量某种机械单片扇叶结构优劣的指标有“质量”与“转动频率”两种参数,为了合理地装配整个风扇,需要相邻组的扇叶质量差达到最小,同时相邻叶片的频率差达到最大。首先构建一个单目标优化的质量分组模型,其后引入递推型动态规划算法,使得相邻组的扇叶质量差达到最小。同时考虑转动频率的影响,再建立一个多目标优化的质量分组模型,采用动态权重线性加权法,通过对比不同权重下相邻扇叶组的最大质量差和相邻扇叶的最大频率差,发现当A目标和B目标的权重均为0.5时,该模型所给出的方案效果最佳。

Comprehensive Evaluation Model of Livable City Based on Fuzzy Comprehensive Evaluation Method

This paper firstly introduced the degree of livability of a city from the social civilization,economic affluence,environmental beauty,resource carrying capacity,and life convenience. Based on the principle of the fuzzy comprehensive evaluation,it analyzed the connection between influencing factors,and established a comprehensive evaluation model for calculation of the livability index of a city. Finally,it obtained the relative livability of each city and the ranking of livability of each city.

中国经济韧性的动态演进特征与区域差异研究

面对各种复杂变化带来的不确定性,增强中国经济韧性是抵御风险冲击的必要条件,也是中国经济长期可持续发展的重要保证。文章基于复杂系统视角,选择熵权TOPSIS法从六个维度测度了1998—2021年中国经济韧性的动态演进特征,运用空间Kernel密度估计方法得到了中国经济韧性的区域差异,使用李雅普诺夫指数分析了中国经济韧性区域差异的动态演进特征。研究发现:中国经济韧性呈动态上升态势,且党的十八大以来中国经济整体韧性及各子维度韧性显著提升;中国经济韧性的东、中、西部地区差异问题仍较为突出,且西部地区内部差异较大,经济韧性的稳定性较弱;中国经济韧性区域差异的动态演进呈现收敛趋势,这为改善中国经济基本面奠定了基础。

乡村振兴与共同富裕耦合协调发展:分布动态、空间差异及收敛性研究

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