基于GPIO的永磁同步电机模型预测转矩控制

在永磁同步电机模型预测转矩控制(model predictive torque control,MPTC)中,由于目标函数控制变量的量纲不同,为了在代价函数中选取最优的权重系数,提出一种改进高斯变异鸽群算法(Gaussian mutation pigeon-inspired optimization algorithm, GPIO)实现权重系数自整定。首先,基于代价函数最小化原则设计PIO的目标函数,用电流id、iq脉动误差均方根评价权重系数。其次,在传统高斯变异算子的基础上引入自适应调整动态参数实现变异。仿真和实验结果表明,将改进后的算法应用于永磁同步电机模型预测转矩系统,能在较少的迭代次数内整定出最优的权重系数,极大地降低了转矩误差和电流谐波畸变率。     

基于一致性的综合能源系统低碳经济调度

综合能源系统(integrated energy system, IES)是解决能源损耗和环境污染问题的有效途径。为提高IES的经济性和环保性,提出了一种基于一致性的IES低碳经济调度策略。首先,在IES中引入阶梯式碳交易机制,在碳交易成本函数构造中,提出一种随着碳排区间而递增的成本系数,通过成本的非线性递增来限制碳排放量。其次,综合考虑能量传输过程中的损耗问题,构建一种结合用能需求和传输损耗的供需平衡约束条件。然后,将电、热、气供能单元的增量成本作为一致性变量,利用领导一致性算法对IES进行分布式调度,进而实现各单元的供能最优输出。最后,结合不同的实验案例验证了所提低碳经济调度策略的有效性。     

基于改进代价敏感直推式支持向量机的发电企业 滥用市场力识别

随着现货市场的加速推进,准确地实时识别滥用市场力行为是电力市场违规行为管理的一项关键性任务。将改进的支持向量机与变分不等式求解算法结合,实现了在只有少量发电企业有标签数据情形下仍可以准确实时地识别发电企业滥用市场力行为。首先,结合电力市场实际情况,构造了滥用市场力识别指标体系,并基于电力市场高维数据的特点对数据进行降维。其次,针对发电企业有标签数据占总体数据小部分及数据不平衡的特点,提出了基于改进代价敏感直推式支持向量机的发电企业滥用市场力识别方法。然后,考虑到半监督算法求解时间较长,将求解问题转化为高效的变分不等式求解问题,并使用定制近邻法进行求解。最后,利用UCI数据集、电力市场仿真数据及实际电力市场数据进行试验。结果表明,该识别方法可以将滥用市场力的发电企业快速有效地识别出来。     

Just-in-time defect prediction for software hunks

Just-in-time defect prediction can remind software developers and managers to verify and fix bugs at the moment they appeared, thus improving the effectiveness and validity of bug fixing. Existing studies mainly focus on just-in-time prediction for software files (JIT-F). JIT-F is a binary classification problem, which classifies (hence predicts) a file change as buggy or clean. This article provides a detailed analysis of just-in-time defect prediction for software hunks (JIT-H), which predicts bugs at a finer level of granularity, and hence further improves the efficiency of bug fixing. Classification is performed using the ensemble technique of bagging—aggregated combinations of random under sampling plus multiple classifiers (J48 and Random Forest). An empirical study with 10 open source projects was conducted to validate the effectiveness of JIT-H. Experimental results show that JIT-H is effective at predicting defects in software hunk changes. Compared with JIT-F, JIT-H is more cost effective. Additionally, analysis on the change features indicates that Text Vector features and hunk change level features are of more importance than features in other groups and levels.     

计及置信容量的光热电站储热容量优化配置

为探索光热电站的容量价值,文中基于光热电站的容量置信度和度电成本,提出一种光热电站集热面积和储热容量优化方法。文中建立光热电站发电效率模型和经济性模型,基于序贯蒙特卡洛方法计算发电系统可靠性,使用粒子群算法计算光热电站置信容量,研究太阳倍数和储热时长分别对光热电站容量置信度和度电成本的影响;并以容量置信度和度电成本作为优化目标,使用加权理想点法建立目标优化函数、熵权法确定指标权重值,对太阳倍数和储热时长进行优化。以西北某地区光热规划为例,使用该地区实际太阳辐照资源数据建立模型,发现随着太阳倍数和储热时长的增加,容量置信度单调递增,而度电成本呈先降后升的趋势,可优化得到约束条件下最佳太阳倍数和储热时长。     

面向国产平台的LLVM自动向量化移植与优化

作为SIMD扩展部件向量化的重要手段,自动向量化已在LLVM编译器中得到实现,但向量长度以及指令集功能的差异,导致国产平台在自动向量化过程中容易错失向量化机会以及向量化后产生倒加速的问题。为使SIMD得到充分应用,结合国产平台的指令集特征完善指令代价信息以提高收益分析精准度,使其在自动向量化后生成后端支持且简洁高效的向量指令。在此基础上,提出一种改进的控制流向量化方法,通过添加指令代价信息提高自动向量化的适配能力,从而形成一套面向国产平台的LLVM自动向量化系统。实验结果表明,相比自动向量化移植前,通过该方法进行移植优化后,SPEC测试的整体性能提升10.8%,TSVC测试集中的加速比提升16%,精准代价指导下的加速比提升42%,控制流向量化下的加速比提升51%。     

Integration of SPC and performance maintenance for supply chain system

In this paper, a supply chain system is viewed as a maintainable system, and the economic-statistical design of a likelihood ratio control chart with a maintenance application is considered for this system. The supply chain system is described by a three-state: normal state, warning state and failure state. A likelihood ratio control chart is used to monitor the system given that only categorical observations can be obtained. When the chart signals, a full inspection is performed to determine the actual system state (normal or warning), and preventive maintenance is immediately performed in the warning state. In addition, the supply chain system must be corrected upon failure (i.e. corrective maintenance), and should be maintained in a scheduled time (i.e. planned maintenance). A mathematical model is developed for the joint optimisation of the control chart parameters and planned maintenance time based on renewal theory. An example is presented to illustrate how to determine the optimal design parameters. We also investigate the effect of coefficients and statistical constraints on the decision variables and the expected cost.     

Incentives for quality improvement efforts coordination in supply chains with partial cost allocation contract

In this paper, we consider quality improvement efforts coordination in a two-stage decentralised supply chain with a partial cost allocation contract. The supply chain consists of one supplier and one manufacturer, both of which produce defective products. Two kinds of failure cost occur within the supply chain: internal and external. The supplier and the manufacturer determine their individual quality levels to maximise their own profits. We propose a partial cost allocation contract, under which the external failure cost is allocated between the manufacturer and the supplier at different rates based on information derived from failure root cause analysis. If the quality levels of the supplier and the manufacturer are observable, we show that the partial cost allocation contract coordinates the supply chain, provided that the failure root cause analysis does not erroneously identify the manufacturer’s fault as the supplier’s, and the supplier does not take responsibility for the manufacture’s fault. In the single moral hazard model, where only the quality level of the supplier is unobservable, the optimal share rates require the supplier to take some responsibility for the manufacture’s fault. However, in the double moral hazard model, where quality levels of the supplier and the manufacturer are unobservable to each other, the optimal share rates require the supplier not to take responsibility for the manufacturer’s fault. It is noted that the root cause analysis conducted by the manufacturer may have its disadvantage in attributing the fault to the supplier when both sides are at fault. We also propose a contract based on the dual root cause analysis to reduce the supplier’s penalty cost. Numerical results illustrate that the partial cost allocation contract satisfies the fairness criterion compared with the traditional cost allocation contract.     

低成本钛合金研究现状与发展趋势

钛合金较高的成本限制了其应用范围,低成本钛合金已成为当前钛合金研究的热点。概述了低成本钛合金国内外的研究现状,着重介绍了宝钛集团研发的低成本钛合金及钛合金的低成本化制备情况,新近研制的BTi31、Ti-3111、BTi-341、BTi-421111、BTi-61111S等低成本钛合金已在汽车、体育休闲等领域获得应用;在钛合金的低成本化制造方面,利用电子束冷床炉熔炼,大量添加返回料,熔炼的扁锭直接轧制板材,显著降低原料成本和加工成本。同时对低成本钛合金的发展方向进行展望,指出今后的研究重点是进一步优化熔炼和加工工艺,提升合金性能水平,提高成材率,拓展应用范围。     

低成本钛合金研究现状与发展趋势

钛合金较高的成本限制了其应用范围,低成本钛合金已成为当前钛合金研究的热点.概述了低成本钛合金国内外的研究现状,着重介绍了宝钛集团研发的低成本钛合金及钛合金的低成本化制备情况,新近研制的BTi31、Ti-3111、BTi-341、BTi-421111、BTi-61111S等低成本钛合金已在汽车、体育休闲等领域获得应用;在钛合金的低成本化制造方面,利用电子束冷床炉熔炼,大量添加返回料,熔炼的扁锭直接轧制板材,显著降低原料成本和加工成本.同时对低成本钛合金的发展方向进行展望,指出今后的研究重点是进一步优化熔炼和加工工艺,提升合金性能水平,提高成材率,拓展应用范围.