A Processor Performance Prediction Method Based on Interpretable Hierarchical Belief Rule Base and Sensitivity Analysis

The prediction of processor performance has important referencesignificance for future processors. Both the accuracy and rationality of theprediction results are required. The hierarchical belief rule base (HBRB)can initially provide a solution to low prediction accuracy. However, theinterpretability of the model and the traceability of the results still warrantfurther investigation. Therefore, a processor performance prediction methodbased on interpretable hierarchical belief rule base (HBRB-I) and globalsensitivity analysis (GSA) is proposed. The method can yield more reliableprediction results. Evidence reasoning (ER) is firstly used to evaluate thehistorical data of the processor, followed by a performance prediction modelwith interpretability constraints that is constructed based on HBRB-I. Then,the whale optimization algorithm (WOA) is used to optimize the parameters.Furthermore, to test the interpretability of the performance predictionprocess, GSA is used to analyze the relationship between the input and thepredicted output indicators. Finally, based on the UCI database processordataset, the effectiveness and superiority of the method are verified. Accordingto our experiments, our prediction method generates more reliable andaccurate estimations than traditional models.

Mass transfer investigation and operational sensitivity analysis of aminebased industrial CO_2 capture plant

In this article, the industrial process of CO_2 capture using monoethanolamine as an aqueous solvent was probed carefully from the mass transfer viewpoint. The simulation of this process was done using Rate-Base model, based on two-film theory. The results were validated against real plant data. Compared to the operational unit, the error of calculating absorption percentage and CO_2 loading was estimated around 2%. The liquid temperature profiles calculated by the model agree well with the real temperature along the absorption tower, emphasizing the accuracy of this model. Operational sensitivity analysis of absorption tower was also done with the aim of determining sensitive parameters for the optimized design of absorption tower and optimized operational conditions. Hence,the sensitivity analysis was done for the flow rate of gas, the flow rate of solvent, flue gas temperature, inlet solvent temperature, CO_2 concentration in the flue gas, loading of inlet solvent, and MEA concentration in the solvent. CO_2 absorption percentage, the profile of loading, liquid temperature profile and finally profile of CO_2 mole fraction in gas phase along the absorption tower were studied. To elaborate mass transfer phenomena, enhancement factor, interfacial area, molar flux and liquid hold up were probed. The results show that regarding the CO_2 absorption, the most important parameter was the gas flow rate. Comparing liquid temperature profiles showed that the most important parameter affecting the temperature of the rich solvent was MEA concentration.

应用盈亏平衡理论指导新疆某奶牛场决策实例分析

为提高奶牛场生产效率,获得最大利润,本研究应用盈亏平衡分析法对新疆某奶牛养殖企业某年度1月份实际的商品奶挤奶牛头数、牛奶产量、牛奶销售价格以及平均奶产量进行分析,预测出该牧场2月份盈亏平衡时的各项生产数据,并对影响养殖企业利润的各因素敏感度进行评估排序。结果发现,在影响该牧场利润的众多因素中,按敏感度由高到低排列依次为商品奶泌乳牛头数、平均奶产量、牛奶销售单价、牛奶产量、变动成本、固定成本、其他收入。以上结果表明,通过优化该养殖场养殖头数等要素,制定出合理的决策方案,可以取得最大利润,并为其运营决策及未来发展规划提供必要的数据支撑和理论指导。

基于PC-Kriging模型的极端环境下海上风机基础可靠性分析

为研究基础结构的材料属性和尺寸对单桩式海上风机基础可靠性的影响,提出基于PC-Kriging模型(Polynomial-Chaos-based Kriging,PC-Kriging)和蒙特卡洛模拟(Monte Carlo Simulation,MCS)方法,结合IEGO学习函数建立的单桩式海上风机基础可靠性分析模型,并通过算例验证了该方法的精确性。以50年重现期的海况为极端环境,考虑材料密度、弹性模量和桩腿壁厚的不确定性,进行单桩式海上风机基础在塔筒顶部位移和应力控制两个失效因素下的可靠性分析,并进行全局灵敏度分析。分析结果表明,单桩式海上风机基础失效概率为8.4×10-3,材料密度对可靠性影响可以忽略不计,而材料弹性模量和桩腿壁厚对可靠性影响较大。

基于阶梯碳价和自适应分时电价的电动汽车有序充电

将阶梯碳价与分时电价的耦合关系进行内联,提出了一种基于阶梯碳价和自适应分时电价的电动汽车有序充电策略。利用蒙特卡罗方法生成电动汽车的无序充电场景;建立阶梯碳价模型和自适应分时电价模型;以电网日负荷均方差最小、电动汽车用户充电总成本最小和发电商碳交易成本最小为目标函数,建立电碳双定价机制下的电动汽车有序充电模型,并采用带精英策略的快速非支配排序遗传算法(NSGA-Ⅱ),结合熵权逼近理想解排序(TOPSIS)模型求解Pareto解集的最优折中解;对4种碳交易机制下的优化结果进行对比分析。仿真结果表明,在有奖励阶梯碳价和自适应分时电价机制下电网负荷波动平抑效果最佳且发电商碳交易成本最小,验证了所提模型的合理性和可行性。

基于矩独立法的异质叠层复合材料铆接工艺参数灵敏度分析研究

为解决碳纤维增强复合材料(Carbon fber reinforced polymer,CFRP)与金属材料叠层构件铆接工艺复杂化的问题,提出了一种基于矩独立方法的叠层复合材料铆接工艺参数灵敏度分析的方法。首先,以CFRP与铝合金(Al)异质叠层材料结构为研究对象,采用有限元方法建立了CFRP/Al叠层结构的铆接仿真分析模型,并通过试验验证了仿真分析模型的正确性。其次,以铆接干涉量为目标,建立了基于随机森林方法的铆接工艺参数代理模型;随后通过代理模型进行数据扩展,以17项铆接工艺参数为输入变量,铆接干涉量为输出变量,采用基于矩独立的PAWN方法进行全局灵敏度分析,并给出了基于该方法的灵敏度系数。在铆接工艺参数对铆接干涉量的全局灵敏度系数中,异质叠层复合材料的弹性模量和厚度的灵敏度系数较大,分别为0.16921和0.11837,其次是系数为0.012的位移载荷和0.011的铆钉直径。其余工艺参数的灵敏度系数较小,一些对铆接干涉量影响很不显著的参数的灵敏度系数接近0。

作业成本法下的本量利分析与敏感性分析实例研究

随着企业机械化程度的增加,制造费用成为企业关注的焦点,当传统的变动成本和固定成本还沉浸在悠久历史的时候,作业成本法的应用开始动摇其理论基础。作业成本法将成本划分为短期变动成本、长期变动成本、固定成本。作为管理会计工具,作业成本法下的本量利分析和敏感性分析与传统的相比具有一定的改进,但是依然不能全面地考虑企业实际情况。文章在作业成本法的基础上,对本量利分析进行修正,引入税金及附加的影响,有创新性地构建作业成本法下的本量利分析模型;而敏感性分析在作业成本法中主要关注作业的敏感性,这提高了本量利分析和敏感性分析的精确度和实用性,为企业生产决策作出更加合理的数据支持。

Monitoring models for base flow effect and daily variation of dam seepage elements considering time lag effect

Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity dam.Sensitivity analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.

Sensitivity analysis of an HgCdTe based photovoltaic receiver for long-wavelength free space optical communication systems

We examine theoretically the performance of an Hg0.77Cd0.23Te based p-n photodetector/HFET optical receiver due to its possible application at 10.6 μm free space optical communication system at high bit rate.A rigorous noise model of the receiver has been developed for this purpose.We calculate the total noise and sensitivity of the receiver.The front-end of the receiver exhibits a sensitivity of -45 dBm at a bit rate of 1 Gb/s and -30 dBm at a bit rate of 10 Gb/s,and the total mean-square noise curren t〈i2n〉=5×10-15 A2 at a bit rate of 1 Gb/s an d〈i2n〉 =10-12 A2 at a bit rate of 10 Gb/s,and a 3-dB bandwidth of 10 GHz.

Parameter Optimization of Nose Landing Gear Considering Both Take-off and Landing Performance of Catapult Take-off Carrier-Based Aircraft

Optimization of the parameters of landing gear systems with double-stage air springs of catapult take-off carrier-based aircraft is here studied based on the mathematical equations of the classic dual mass spring-damper dynamic model.Certain standards for both take-off and landing performance are put forward.The contradictory factors between take-off and landing processes are analyzed.The optimization of oil in the pin area and the area near the rear oil hole is performed.Then these optimized parameters are used to assess the influence of the initial pressure of the low chamber,the ratio of the high chamber to the low chamber,and the tire inflation pressure on the performance of arresting landing and catapult take-off.The influences of these parameters on carrier-based aircraft and the aircraft-carrier on aircraft catapult take-off is also assessed.Based on the results of the simulation,respective take-off criteria must be drafted considering different types of aircraft and different take-off load cases,all of which must be matched to parameters relevant to catapult take-off.

A simplified physically-based breach model for a high concrete-faced rockfill dam:A case study

A simplified physically-based model was developed to simulate the breaching process of the Gouhou concrete-faced rockfill dam （CFRD）, which is the only breach case of a high CFRD in the world. Considering the dam height, a hydraulic method was chosen to simulate the initial scour position on the downstream slope, with the steepening of the downstream slope taken into account; a headcut erosion formula was adopted to simulate the backward erosion as well. The moment equilibrium method was utilized to calculate the ultimate length of a concrete slab under its self-weight and water loads. The calculated results of the Gouhou CFRD breach case show that the proposed model provides reasonable peak breach flow, final breach width, and failure time, with relative errors less than 15% as compared with the measured data. Sensitivity studies show that the outputs of the proposed model are more or less sensitive to different parameters. Three typical parametric models were compared with the proposed model, and the comparison demonstrates that the proposed physically-based breach model performs better and provides more detailed results than the parametric models.

An efficient sensitivity analysis for energy performance of building envelope: A continuous derivative based approach

Within the framework of building energy assessment,this article proposes to use a derivative based sensitivity analysis of heat transfer models in a building envelope.Two,global and local,estimators are obtained at low computational cost,to evaluate the influence of the parameters on the model outputs.Ranking of these estimators values allows to reduce the number of model unknown parameters by excluding non-significant parameters.A comparison with variance and regression-based methods is carried out and the results highlight the satisfactory accuracy of the continuous-based approach.Moreover,for the carried investigations the approach is 100 times faster compared to the variance-based methods.A case study applies the method to a real-world building wall.The sensitivity of the thermal loads to local or global variations of the wall thermal properties is investigated.Additionally,a case study of wall with window is analyzed.

Total Sensitivity Index Calculation of Tool Requirement Model via Error Propagation Equation

A new and convenient method is presented to calculate the total sensitivity indices defined by variance-based sensitivity analysis. By decomposing the output variance using error propagation equations, this method can transform the ＂double-loop＂ sampling procedure into ＂single-loop＂ one and obviously reduce the computation cost of analysis. In contrast with Sobors and Fourier amplitude sensitivity test （FAST） method, which is limited in non-correlated variables, the new approach is suitable for correlated input variables. An application in semiconductor assembling and test manufacturing （ATM） factory indicates that this approach has a good performance in additive model and simple non-additive model.

两级蓄冷跨临界压缩CO_(2)混合工质储能系统特性分析

为了解决高压CO_(2)在高环境温度下难以冷凝的问题,提出两级蓄冷跨临界压缩CO_(2)混合工质储能系统。采用CO_(2)与低沸点有机工质混合的方法提高工质的冷凝温度,同时,利用两级甲醇蓄冷实现系统内部冷能循环利用。从环境性、临界温度、温度滑移、可混合性等方面确定合适的CO_(2)混合工质及其组分质量分数范围。建立储能系统的热力学分析模型,探究节流压力、高压储液罐压力、有机工质质量分数等关键参数对系统性能的影响规律,并研究系统内部能量流动规律,得到主要部件的(火用)损失。研究结果表明:随着有机工质质量分数的增加,蓄冷介质温度增加,系统安全性提高;与纯CO_(2)工质相比,系统的充放电效率和能量密度略有降低;CO_(2)/R32混合工质的充放电效率最高为62.29%,CO_(2)/pentane混合工质的能量密度最高为21.37 kW·h/m^(3)。

掺合料影响沙漠砂水泥基材料力学性能的敏感性分析

为探究沙漠砂水泥基材料力学强度对不同掺合料的敏感性,通过正交试验进行抗折强度及抗压强度的测试研究,结果采用极差分析和方差分析的方法进行评定,并对最优水平组合进行验证,总结其受力规律。结果表明:沙漠砂水泥基材料力学强度对不同掺合料的敏感性顺序为脱硫石膏>硅粉>粉煤灰>石灰>可再分散性乳胶粉。掺合料最优水平组合为5%粉煤灰,20%硅粉,5%脱硫石膏,3%石灰,1%可再分散性乳胶粉。最优配合比试件的抗折及抗压强度与不加任何掺合料的试件相比分别提升了40.43%和130.04%。研究成果对沙漠砂水泥基材料的应用及相关研究提供了参考。

基于轻量级卷积神经网络的科技型中小企业估值研究

对科技型中小企业进行科学合理估值有利于其募集资金从而健康发展,但传统估值方法的准确度和适用性均有待考量。鉴于此,利用文献分析与关键词提取方法,初步从相关文献中提取科技型中小企业估值指标,并通过德尔菲法筛选得到能体现科技型中小企业核心能力的关键指标;进一步设计轻量级卷积神经网络(TecNet)结构,基于大数据训练构建适用于科技型中小企业的估值模型;最后以10家样本企业为例,对其2017—2021年度预测值与真实值相对误差进行拟合分析以及敏感度分析,以验证所构建估值模型的有效性。结果表明:模型预测的拟合曲线与真值重合度较高,平均相对误差为3.43%,且90%的样本的相对误差在10%以内,说明Tec Net模型具有科学有效性;将关键指标提升5%时,硕士及以上比例、研发投入占营业收入比例以及专利数对估值结果浮动程度最高,分别为16.51%、16.10%和11.87%,表明科技型中小企业价值对这3项指标最为敏感。因此,科技型中小企业发展应着眼于其关键指标,通过优化员工学历层次、加大研发投入等措施提高智力资本,并持续加强技术创新。

基于CEL有限元法的大管径钢管桩贯入海基过程的承载力分析

鉴于耦合欧拉-拉格朗日(Coupled Eulerian-Lagrangian, CEL)有限元方法在计算分析接触大变形问题时的优势,建立了大管径钢管桩贯入海基的CEL有限元模型,即在被贯入的海基层采用欧拉有限元法建模,其它层采用拉格朗日有限元法建模,两者之间通过罚函数的接触算法进行耦合.在欧拉有限元模型中,采用算子分裂技术.为兼顾计算模型的精度和效率,本文先对模型的网格密度和贯入速度进行稳定性分析,以此确定合适的网格模型和适宜的贯入速度,同时验证CEL方法在贯入模拟中的可行性.随后针对不同土体类型和不同土体参数变化,探究土体贯入阻力随贯入深度的变化规律.计算结果表明砂土的贯入阻力最大,粉砂土次之,粘土的贯入阻力最小;且贯入阻力对土体内摩擦角的变化最为敏感,对土体粘聚力的变化比较敏感,而对土体模量的变化不敏感.

气体扩散系数法估算水体反硝化速率

近年来基于经验系数或者机理过程的气体扩散系数法逐渐被应用于水体反硝化速率的估算,为了探究该方法的可靠性、适用性和不确定性,本研究在不同硝态氮浓度(0、1、2、4、6 mg·L^(-1),以N计)静态水体条件下比较了密闭培养法和气体扩散系数法。结果表明:BO04、CL07和Xia213种气体扩散系数模型估算的反硝化速率与水体硝态氮浓度的关系均符合米氏方程(R2=0.9946,P<0.01)。3种扩散系数法与密闭培养法测定的水体反硝化速率之间均有显著的线性关系(R2=0.7767,P<0.05),但斜率各不相同,其中CL07和Xia21模型的估算结果均与密闭培养法的测定结果较为接近,斜率分别为1.22和0.59。进一步应用蒙特卡洛分析法对CL07模型进行参数敏感性分析发现,风速、流速和水温是模型最为敏感的3个因子,其无偏百分比差异分别为12.13%、9.49%和9.42%。研究表明,气体扩散系数法可以较准确地估算水体反硝化速率,为大尺度原位开展水体反硝化估算和氮素循环提供方法基础,但是需要根据实地环境条件选择和标定模型。

超参数自适应的MOEA/D-DE算法在翼型气动隐身优化中的应用

MOEA/D-DE算法易于实现,被广泛应用于处理多目标优化问题,但其超参数对算法性能影响较大。基于MOEA/D-DE算法框架,利用Sobol全局灵敏度分析方法对差分进化算子中的交叉控制参数进行改进,使用莱维飞行机制控制比例因子,使算法中的超参数拥有自适应能力,得到超参数自适应的MOEA/D-DE算法——MOEA/D-DEAH算法;对MOEA/D-DEAH算法、不同超参数设置的MOEA/D-DE算法和NSGAⅡ算法进行函数测试和翼型气动隐身优化算例对比。结果表明:MOEA/D-DEAH算法性能良好,具有较强的鲁棒性,气动隐身优化效果也比其他算法更好。

南京德基广场三期超高层建筑结构设计

由于建筑平面、立面上的需求,塔楼在底部存在较大收进且结构角部在中、高区逐层内收,为避免过多的转换结构构件,最终采用斜柱的方式满足建筑要求;为解决结构侧向刚度不足的问题,设置了伸臂桁架加强层,是一个颇具有代表性的有较多斜柱的带加强层超高层建筑结构。以层间位移角为约束条件,基于增量敏感性优化方法对伸臂桁架的位置及设置道数进行研究分析,基于力学原理分析了斜柱结构的受力机理,并对受其影响的钢梁、楼板进行专项分析,通过ABAQUS有限元软件对分叉柱关键节点进行有限元分析。结果表明:在斜柱楼层范围内,斜柱轴力产生的水平力在核心筒墙体内会造成水平剪力,其拉、压受力特性与斜柱倾斜方向相关,应重点对内倾柱进行加强。斜柱转折处的楼板受到较大拉力时会发生开裂,因此钢梁应考虑能独立承担斜柱的水平分力,按拉、压弯构件进行强度验算。斜柱转折楼层、伸臂加强层及其相邻楼层,均为楼板应力较大位置,设计中需重点关注及加强。通过专项分析加强后主体结构能达到预定的性能目标,且结构关键构件在罕遇地震下不屈服,具有良好的延性。