Parallel Computing Framework for Optimizing Construction Planning in Large-Scale Projects

Available construction optimization models can be used to generate optimal tradeoffs between construction time and cost, however their application in optimizing large-scale projects is limited due to their extensive and impractical computational time requirements. This paper presents the development of a parallel computing framework in order to circumvent this limitation. The framework incorporates a multi-objective genetic algorithm module that identifies optimal trade-offs between construction time and cost; and a parallel computing module that distributes genetic algorithm computations over a network of processors. The performance of the framework is evaluated using 150 experiments that represent various combinations of project sizes and numbers of processors. The results of this analysis illustrate the robust capabilities of the developed parallel computing framework in terms of its efficiency in reducing the computational time requirements for large-scale construction optimization problems, and its effectiveness in obtaining high quality solutions identical to those generated by a single processor.     

基于粒子群算法的冷连轧张力优化计算

针对冷连轧机高速轧制过程中带钢容易发生打滑的现象,分析了这种打滑现象的物理过程,建立了打滑因子的数学模型,用来表征打滑现象发生的概率。应用该模型研究了基于粒子群优化算法的冷连轧机架间张力优化算法。采用某钢厂现场轧制数据进行了优化算法的仿真试验,结果表明,经过优化后的打滑因子明显减小,打滑现象发生的概率显著降低,通过张力的优化可以很好地控制打滑现象的发生。     

基于FANUC系统下数控机床的程序解析与优化

文章以包钢石油套管生产线之一大线FANUC系统中用户程序的解析与优化结合实践给出论证,同时就主轴电机特性做出分析,为参数科学设置提供合理依据。     

Optimization Research: Enhancing the Robustness of Large-Scale Multiobjective Optimization in Construction

Many construction planning problems require optimizing multiple and conflicting project objectives such as minimizing construction time and cost while maximizing safety, quality, and sustainability. To enable the optimization of these construction problems, a number of research studies focused on developing multiobjective optimization algorithms (MOAs). The robustness of these algorithms needs further research to ensure an efficient and effective optimization of large-scale real-life construction problems. This paper presents a review of current research efforts in the field of construction multiobjective optimization and two case studies that illustrate methods for enhancing the robustness of MOAs. The first case study utilizes a multiobjective genetic algorithm (MOGA) and an analytical optimization algorithm to optimize the planning of postdisaster temporary housing projects. The second case study utilizes a MOGA and parallel computing to optimize the planning of construction resource utilization in large-scale infrastructure projects. The paper also presents practical recommendations based on the main findings of the analyzed case studies to enhance the robustness of multiobjective optimization in construction engineering and management.     

液压弯辊控制系统动态特性分析及参数优化研究

针对液压弯辊伺服控制系统,建立了电液伺服压力控制系统动态特性的数学模型,采用MATLAB软件的SIMULINK模块构建其动态特性结构框图,对影响系统动态特性的有关参数进行了分析,得出了各有关参数变化对系统动态特性的影响曲线规律,研究了系统各主要参数与抗干扰能力的关系,提出了控制性能的优化建议.研究结果表明:通过优化有关参数,可大大改善控制系统的动态性能.     

大型钢锭轧板开裂和穿孔缺陷分析及浇铸工艺优化

分析了S355JR和S355J2低碳钢(/%:0.17～0.20C、0.30～0.55Si、1.40～1.60Mn、≤0.020P、≤0.015S、0.020～0.040A1、0.020～0.030Nb)28～40 t钢锭轧成230～400 mm钢板出现的开裂和穿孔缺陷。通过提高浇钢工操作水平,根据钢水过热度控制本体浇铸和帽口浇铸时问;控制精炼终点[O]≤25×10^-6以及钢中铝含量0.020%～0.040%等优化浇铸工艺措施使钢锭探伤合格率提高到96.8%。     

Fracture Mechanics Model for Analysis of Plain and Reinforced High-Performance Concrete Beams

In developing a one-dimensional analysis and design procedure for reinforced concrete structures, research is generally based on yield phenomena and the plastic flow of steel in tension and concrete in compression. The ability of concrete to resist tension is considered in the form of tension stiffening or is completely disregarded. This procedure does not account for the influence of structural size in changing the failure mode and the stress distribution across the uncracked or cracked ligament. The key factor affecting this stress distribution is found to be the strain-softening modulus. This paper presents an improved model that is based on the fundamental equilibrium equation for the progressive failure of plain concrete beams. The concrete stress-strain relationship in tension is derived by calculating the peak tensile stress and softening modulus for different depths of beams on the basis of the fracture parameters obtained with the size effect law. Thus, the proposed model uses the peak tensile stress and the softening modulus, which vary depending on the size of the beam. To study the effect of the strength of high-performance concrete (HPC) on the concrete tensile stress-strain relationship, the experimental load-deflection plots of different-sized beams are compared with those obtained by using the proposed analytical model for eight different mixes made with locally available fly ash and slag. The model is also extended for lightly reinforced concrete beams, and the results are compared with those in the literature and are found to be in good agreement.     

热连轧粗轧机速度控制的分析与优化

粗轧机速度控制采用低速咬钢、高速轧制、低速抛钢的可逆轧制模式。因为受限于上下主电机轧制电流差别大,主传动系统的轧制速度不高。分析发现,主传动控制系统以牺牲电流为代价保证上下电机转速平衡。通过在主传动控制程序中引入负荷平衡环节后,使上下传动电机电流差控制在8％以内,同时提高了粗轧机各道次轧制速度,使单卷轧制时间比未提速前节约了8s,提高了粗轧机的轧制节奏。     

SPHC热轧带钢质量过程能力控制分析及优化

对5 000炉SPHC钢化学成分和机械性能的过程能力指数进行了分析计算,优化了炼铁配矿及炼钢操作工艺。结果表明,SPHC钢的碳含量、磷含量过程能力指数分别由三级提高至一级和二级,锰硫比的过程能力指数由四级提升至二级。     

大型铝电解槽低电压物料与能量双平衡控制技术

介绍大型铝电解槽低电压物料与能量双平衡控制的技术和6年的应用实践。通过采用实时天平式氧化铝浓度控制技术,电解槽氧化铝浓度可以平稳均匀控制在1.5%～2.5%。通过对槽电压和自动添加氟化铝进行实时控制、以及对电流效率的评估,从而保证了电解槽能量的平衡稳定。     

一类不确定时滞大系统的分散模型参考自适应控制

运用分散模型参考自适应控制方法研究了一类不确定时滞大系统问题.在选择参考模型时,根据系统所期望的性能指标,考虑各子系统的相互作用,保留了互联项.这类不确定大系统的关联及干扰是时变不确定的.在这种不确定性界存在但却未知的情形下,基于Lyapunov稳定性理论,给出了其分散自适应控制律,并证明了整个互联大系统是一致最终有界的.     

Stream Sockets versus Web Services for High-Performance and Secure Structural Analysis in Internet Environments

The increased growth of internet use in the last several years has opened up new possibilities for structural engineering analysis, moving from personal computer oriented software to client–server distributed software. In this paper two client–server applications for structural engineering based on stream sockets and on web services are presented. These two technologies have been chosen to compare, in terms of performance and complexity, new internet protocols with traditional ways of implementing client–server applications. Moreover, special care has been taken in the security aspects as the internet has become much more susceptible to breaches of security. Therefore, two new applications based on the same technologies have been created that guarantee a secure use of structural software. Also, two different client applications are presented to emphasize the versatility and power of internet distributed technology—one as a stand-alone application and the other as an integrated commercial computer-aided design program.     

大型输送泵站智能管控系统研究及应用

阐述了建立大型输送泵站工艺参数模型的过程,实现了关联泵站整体自动联动调节,达到了设备高效稳定运行,降低生产成本,节约人力资源的目的。     

RH炉控制工艺的优化及效果

通常钢厂生产品种钢工艺流程为：铁水预处理→转炉→LF及钙处理→RH→浇铸。在上述工艺流程的基础上,对RH炉控制进行了新工艺研究,为冶炼高级别品种钢创造条件。     

2250mm热连轧板带宽度控制优化

结合设备特点、产品宽度控制手段以及宽度控制理论,详细分析了2250mm热连轧生产线的成品宽度尺寸波动的影响因素。通过对定宽机的短行程控制消除头尾宽展的异常变化,以板坯宽度尺寸的测量消除来料宽度尺寸波动的影响,以精轧张力控制以及立辊的自由张力控制系统的优化消除头尾拉窄现象,有效地解决了宽度控制中存在的问题。     

420kA大型铝电解槽槽上部集气烟道结构优化改造

对420kA大型铝电解槽槽上部集气烟道的结构优化与改造进行了研究。利用FLUENT软件对某公司420kA电解槽V形单烟道内烟气流动状况进行了仿真模拟,获得了烟气在出口压力设定为-400Pa时电解槽槽腔以及集气烟道内的速度场、压力场的分布情况。针对其不足,将其优化改造为上位双烟道分区集气结构,通过模拟计算结果和生产现场实际数据进行对比,仿真结果正确可靠。优化改造后的烟道集气效果较好,可实现烟道集气均匀,能提高烟道集气效率,可实现电解槽的节能降耗。通过进一步模拟计算获知,当优化改造后的烟道出口压力调节至-300Pa时即可满足生产和设计要求。     

Introduction into MMK Blast Furnaces of an Automated System for Smelting Control,Optimization, and Prediction

Metallurgist - Results are provided for work conducted in the Magnitogorsk Metallurgical Combine blast-furnace workshop for production satisfaction of a blast-furnace automatic control system by...     

基于神经网络的动态矩阵控制

利用神经网络优化性能指标实现了动态控制,并给出了计算机模拟实例。     

Parallel Computing Techniques for Sensitivity Analysis in Optimum Structural Design

Among different activities of the optimum structural design using the gradient-based optimization approaches, design sensitivity analysis is the most time-consuming computational process. By introducing parallel computing techniques for sensitivity computation, significant speedup has been obtained in optimum structural design. Computation of design sensitivities is characteristically uncoupled, thus opening the door to parallelization. In this paper, two types of approaches viz. single-level and multilevel parallelisms are pursued for design sensitivities. The design sensitivities are computed using analytical and finite-difference methods. Numerical studies show that the performance of the parallel algorithms for design sensitivities on message passing systems is very good. Good speedups have been achieved in parallel multilevel sensitivity calculation. The parallel algorithms for design sensitivity analysis have been implemented on message passing parallel systems within the software platform of Parallel Computer Adaptive Language.