灵敏负荷在配电网控制中的约束条件和容量估算

论述了配电网中的灵敏负荷,作为资源的灵敏负荷所具有的特点,给出了灵敏负荷控制系统的示意图。重点讨论了灵敏负荷优化控制约束条件以及相关的数学模型,即在考虑某些实际问题的情况下,给出了灵敏负荷最优控制的约束条件,设定了关闭和正常运行两种状态的约束关系,在限定的必要条件下,求解最优化目标函数。以沈阳市为例,根据所测日负荷数据分析曲线图,对灵敏负荷的容量进行了估算,对于指导灵敏负荷控制起到重要的作用和实用效果。利用好灵敏负荷资源,对提高电力系统的稳定性,降低运行成本有着重要的实际意义。     

Freights loading optimization with balanced and unconcentrated loading constraints

The optimization of high density and concentrated-weight freights loading requires an even distribution of the freight＇s weight and unconcentrated loading on the floor of the car. Based on the characteristics of concentrated-weight category freights, an improvement method is put forward to build freight towers and a greedy-construction algorithm is utilized based on heuristic information for the initial layout. Then a feasibility analysis is performed to judge if the balanced and unconcentrated loading constrains are reached. Through introducing optimization or adjustment methods, an overall optimal solution can be obtained. Experiments are conducted using data generated from real cases showing the effectiveness of our approach： volume utility ratio of 90.4% and load capacity utility ratio of 86.7% which is comparably even to the packing of the general freights.     

复杂构造转换波静校正方法研究及应用

目前转换波静校正技术方法众多,已成为多分量勘探不可或缺的重要组成部分。然而,这些方法还面临一些实际困难和问题：(1)面波反演法存在面波发散、难以确定频散周期及复杂探区面波信噪比低、频散曲线拾取困难等问题;(2)初至波静校正方法中的层析反演和折射法的转换波初至信噪比低,尤其在复杂探区拾取初至很难;(3)共检波点道集叠加纵波构造约束法要求地下反射界面变化相对平缓或者水平。因此,上述方法目前都不适合复杂构造转换波静校正。为此,提出一种复杂构造转换波静校正方法,具体步骤为：(1)通过层位拉平方法消除转换波静校正构造项,克服层位基本水平的限制。首先拾取P-P波CMP叠加信噪比较高的构造层位,并计算层位拉平投影时差,用投影时差“拉平”叠前数据;(2)将层位拉平数据转换到共检波点域并重新完成共检波点P-P波速度分析,以使共检波点道集的每道速度相同,消除复杂构造横向速度剧烈变化及速度分析精度不高造成的道间动校正误差,既可以使共检波点同相叠加、提高信噪比,又减少了速度精度不高对地震道剩余静校正量的影响;(3)把P-P波构造层位拉平的投影时差转换到P-SV域拉平P-SV波叠前数据,在共检波点域重新完成P-...     

带约束的一维时频电磁联合反演研究

利用时频电磁资料可同时获取时间域及频率域电磁信息。相比单一时间域或频率域电磁信号,综合利用时频电磁信息可明显提高电性反演精度。为获得精细地电模型,基于正则化反演方法,融合数据约束、模型约束及步长约束,提出一种一维自适应时频电磁联合反演算法。该算法对时间域和频率域数据平衡因子及正则化因子采用自适应调整方案,同时将模型参数搜索范围约束与WOLFE准则相结合,在限制参数搜索范围的同时约束迭代步长,确保反演的稳定性和精度。使用经典层状模型、含噪声的页岩气地电模型及实测数据对该反演方法进行测试与分析,结果表明带约束的时频电磁联合反演方法可有效提高复杂模型电阻率反演的分辨率,对提高时频电磁方法油气藏识别精度具有实际意义。     

电力现货市场前瞻优化的周期选择

前瞻优化对于适应可再生能源的发展需求,确保电力现货市场良好运作,发挥着重要作用.而合理的前瞻周期选择能够有效地提高电力系统全局优化的可靠性与经济性.因此,迫切需要对前瞻周期的选择问题进行研究.为此,文中首先通过建立电力现货市场前瞻优化模型,推导了优化模型下的节点边际电价公式,分析了跨时段约束对节点边际电价的影响.然后,构建了前瞻周期的偏差量模型,设计了电力现货市场前瞻周期的选择流程.最后,通过不同的算例,揭示了不同前瞻周期下跨时段约束对节点边际电价的影响,验证了流程所选最佳前瞻周期的有效性.     

利用转子动能的风机辅助频率控制最优策略

风机增加辅助频率控制模块是解决新能源取代同步机导致的电力系统频率安全问题的一种方案,其中利用转子动能的调频模式可以使风机运行在最大功率点,经济性比功率备用模式更好。已有研究主要让风机通过虚拟惯量和频率下垂控制模拟同步机,却未充分利用风机控制灵活、可塑性强的优点,且未考虑风机转子动能限制及系统频率二次跌落。论文跳出虚拟惯量加频率下垂控制的传统框架,提出利用转子动能的风机辅助频率控制最优策略。首先将风机输出功率曲线作为决策变量,通过优化得到最优功率曲线,然后设计对应的辅助频率控制策略,实现最优输出功率曲线。仿真结果验证所提策略的效果,并说明风机辅助频率控制不应局限于模拟同步机,而是有更优的策略。     

TWO KINDS OF VARIANT IN SHAPE MEMORY MATERIAL

In shape memory materials,that have been trained to have a two way shape memory effect(TWSM),themartensitic variants are classified into two groups,i.e.,preferentially oriented variants and self-accommodatingvariants.Applied stress may promote or constrain the transition of preferentially oriented variants and so changetransformation temperatures but has no essential effect on self-accommodating variants.According to the pointof view mentioned above,some experimental phenomena during thermocycling of a TWSM device may be ex-plained,such as the absence of synchronization between the plot of resistance change.temperature and the plotof memory strain vs.temperature.     

基于工程优化设计的模具参数化CAD系统

提出了基于工程优化设计的参数化CAD系统的产品建模方法与实现途径 ,简述了工程约束与约束优化求解 ,阐述了工程优化设计在参数化CAD系统中的应用。经工程实践 ,该系统可以有效提高模具设计的自动化程度     

A note on the optimal pricing and production decisions with price‐driven substitution

Recently, Kim and Bell ( 2011 ) developed a revenue managemnent pricing model with price‐driven substitution. The authors considered production decisions under unlimited production capacity and investigated the impact of price‐driven substitution on a firm's pricing and production decisions. The authors modeled the consumer demands for each market segment as linear additive demand function based on exogenous variables, where demand substitution occurred as a function of price differences between the two products. In this article, we extend this work to examine the impact of a production capacity constraint on the firm's joint pricing and inventory decisions. Based on this extended model, we investigate the impact of price‐driven substitution on a firm's pricing and production decisions where there is a limit on total capacity. We show how revenue managers should adjust prices and production levels to take into account price‐driven substitution under a capacity constraint setting. Both deterministic and stochastic models are developed, and the impact of price‐driven substitution and a capacity constraint on the optimal prices, production levels, and revenues is illustrated.     

受限模糊网络可信近邻查询

针对不确定网络环境下的近邻查询问题,给出一种新的解决方法.将不确定网络建模为模糊图,定义模糊图中两点间的可信最短路径距离和可信最短路径期望距离,在可信距离基础上,提出模糊图可信近邻查询概念,并给出网络距离受限条件下的模糊图可信近邻查询算法和即时可信近邻查询算法.算法采用模糊模拟方法降低问题难度,使用网络距离约束缩小搜索空间,运用优先队列快速得到满足精度ε要求的可信近邻查询结果.算法的时间复杂度分别为O((2r +Ar)(e+nlgn)+hlgh+ lgn)和O(e+ (n+1)lgn).理论分析与实验结果表明,可信近邻查询算法能够从模糊角度解决不确定网络环境下的近邻查询问题.