基于改进AGA算法求解含交易费用改进组合投资模型

本文根据国内证券交易市场的实际情况提出了含交易费用的投资组合优化模型,并利用改进自适应遗传算法（AGA）求解该模型,最后结合实际数据,利用Matlab语言编程仿真求解并取得了很好的效果。     

卫星遥感影像RPC参数求解算法研究

针对国内外在求解RPC模型参数算法上需要初值、迭代处理,且求解过程相当复杂的缺憾,提出了基于全球DEM的RPC模型参数求解算法,利用SPOT-5、CBERS-2以及ERS卫星影像进行实验,获得对卫星遥感影像几何处理有意义的结论,并对卫星影像在利用严格成像几何模型求解RPC模型参数时做了控制点格网大小及高程分层数对求解精度的影响实验,得出对卫星遥感影像,采用控制点的格网大小为20×20、高程分层为3可以达到精度和效率的平衡。     

多障碍环境中移动机器人的光滑轨迹规划

根据轮式移动机器人参数化轨迹生成模型,结合多障碍物结构化环境中障碍物的建模,把其和参数化轨迹规划模型融合,得到了具有一般性的多障碍物环境中轮式移动机器人光滑轨迹规划模型;并利用最优化控制原理,建立了任意性能指标下,多障碍物环境中最优参数化轨迹生成模型。结合数值求解方法,推导了多障碍物环境中参数化轨迹规划非线性求解模型的求解方法。最后通过仿真验证了参数化轨迹规划求解模型的正确性。     

基于搜索论的一种机器故障查找模型

机器故障查找是机器维修的一个重要环节,在搜索论的基础上提出了一种机器故障查找模型,利用启发式贪 婪算法求解该模型,并进行了实际数据验证。实验结果表明了利用该模型的     

石化企业蒸汽动力系统的多周期运行优化

为了满足石化企业工艺过程对蒸汽和电力不断变化的需要,实现企业降低成本、节能降耗的目的,必须保证蒸汽动力系统在最优状态下运行。本文针对这一问题建立了综合考虑设备启停费用的蒸汽动力系统多周期最优运行的混合整数线性规划模型,并将锅炉和汽轮机的模型进行了合理的线性化。该模型既保证了系统运行优化求解精度,又避免了非线性模型求解困难的问题,利用通用建模工具GAMS建模求解,并通过实例证明了利用本文建立的模型,在较短的时间内得到了最优的计划调度方案,并且节省了大量的运行成本。     

基于Marquardt和Runge-Kutta算法的发酵过程建模

利用简单的线性模型很难描述发酵这类复杂的非线性动态过程,因此需要利用非线性方法对该类过程进行建模。为此,提出了利用基于Marquardt算法的非线性回归方法和基于四阶Runge-Kutta算法的非线性微分方程求解方法对发酵过程进行建模分析;并进一步利用统计方法分析了该非线性回归方法的有效性。该方法应用于黄酒发酵过程中,实现了黄酒发酵过程模型的求解和模型参数的动态优化。     

随机需求下闭环供应链网络设施竞争选址模型研究

利用均衡理论和变分不等式研究工具,建立了随机需求情形下多层竞争型闭环供应链网络均衡模型,并在此基础上,构建了均衡约束数学规划模型,即设施竞争选址模型.利用均衡模型来捕捉由新进设施的进入所引起的网络均衡状态的变化,并将其引入位置决策过程.根据模型特点,提出了遗传算法与修正投影算法相结合的求解策略.最后利用提出的模型和求解算法对算例进行计算与分析,得到了网络竞争趋势变化情况、新设施的位置策略及其生产运营决策.     

面向业务问题求解的知识资源特定领域建模方法

针对企业中解决业务问题时知识资源利用不合理的问题,提出一种面向业务问题求解的知识资源特定领域模型。首先从领域纲要出发,将业务问题求解领域的基本元素描述出来,并详细分析其中对象之间的关系;然后通过在领域模板中建立的问题-知识事件驱动过程链(PK-EPC)模型对问题求解的流程进行格式化,并匹配到相应的知识单元;其次是通过对应的应用模型对业务问题进行分解,并将前面的知识单元与知识载体匹配。根据前面的模型可得出可供企业选择的集成业务活动、知识单元和知识载体的多层次求解方案模型,为企业业务问题求解提供了快捷准确的方法。最后基于Java设计了面向业务问题求解的企业求解方案建模系统,通过实例验证了该模型的可行性。     

计算机应用基础试题库组卷系统的设计

在计算机应用基础课程建设中,设计了一个通用的基于知识的自动组卷系统。文章介绍了试题库的设计,建立了组卷系统的数学模型,并研究了其求解方法,将有约束的多目标优化模型转化为无约束的单目标优化模型,并利用遗传算法对其进行求解。     

催化裂化反应—再生系统稳态模拟

为克服催化裂化反应—再生系统中微分代数方程求解的复杂性并提高稳态求解的收敛速度,加快系统整体模拟效率,本文采用GDEM加速稳态模型求解。本文基于基准假组分法建立了系统的稳态模型,根据装置的信息流图,通过序贯模块法进行整个系统的稳态模拟并给出模型求解策略和求解流程图。利用工业数据验证所建立模型的准确性和可靠性,通过3种不同的收敛算法考察本文模型对切断量初值的敏感性并比较3种算法下稳态模拟的计算速度及迭代次数。最后考察剂油比对油气产率及反应温度的影响,体现合理选择操作条件的重要性。     

ROD-based hybrid TH precoding and combining for mmWave large-scale MIMO systems

Hybrid precoding is one of key techniques for millimeter wave (mmWave) large-scale multiple-input multiple-output (MIMO) systems. This paper considers a nonlinear hybrid precoding architecture which consists of a nonlinear unit, a reductive digital precoder and a constant modulus radio frequency (RF) precoder, and presents a novel hybrid Tomlinson-Harashima (TH) precoding and combining algorithm. Firstly, due to the intractability of the sum rates maximization problem for such a nonlinear hybrid precoding architecture, a tractable three-stage optimization problem is constructed through the lower bound of the sum rates, which allows the digital precoding matrix, the RF precoding matrix and the RF combining matrix to be optimized sequentially and independently. Then, in order to solve the three-stage optimization problem effectively, a novel row orthogonal decomposition (ROD) is defined. Based on the ROD, it is interesting that the necessary and sufficient condition of the optimal digital precoding matrix can be obtained, and a near-optimal RF precoding matrix can be derived. Finally, the optimization of the RF combining matrix is reformulated as a unimodular quadratic programming and solved by a generalized power method. Theoretical analyses and simulations indicate that the proposed ROD-based hybrid TH precoding and combining algorithm can offer a higher sum rates and a lower bit error rate with a comparable complexity in comparison to the previous works.     

关于一种网格运行时结构的若干注记

进程是传统计算机系统的一个核心概念，自1960年出现以来一直沿用至今，进程的一个主要目的是为主体提供一种运行时结构，在操作系统和处理器硬件支持下，代表主体访问和使用各种资源，与传统的单机和并行机计算平台相比，网格计算机中进程所对应的概念面临新的挑战，包括网格资源繁杂、自主控制的条件下的单一系统映像和资源的共享与协同、与特定操作系统的松耦合、时间和空间的流动性、更高级的交互性，提出一种称为网程(grip)的运行时结构，试图解决上述问题，网程运行在网格操作系统之上，代表网格主体，访问和使用网格资源。     

Genetic algorithm-based optimisation of load-balanced routing for AMI with wireless mesh networks

The advanced metering infrastructure (AMI) in a smart grid contains hardware, software, and other electronic components connected through a communication infrastructure. AMI transfers meter-reading data between a group of smart meters and a utility centre. Herein, a wireless mesh network (WMN) with a random mesh topology is used to deploy the AMI communication network. In a WMN, paths are identified using a hybrid wireless mesh routing protocol (HWMP) with a load balancing feature called load aware-HWMP (LA-HWMP). These paths reduce the demand on links with a minimal air time metric; however, the delay in the data transmission of certain smart meters is high, given the large number of retransmissions caused by packet drop. To avert this problem and enhance the end-to-end delay, a genetic algorithm is applied on the LA-HWMP to obtain the optimal path. The optimisation process will result in the selection of paths with minimal delay. The genetic algorithm is developed with a rank-based selection, a two-point crossover, and a random reset mutation with a repair function to eliminate duplicate entries. The proposed method is compared with the HWMP, the LA-HWMP, and a state-of-the-art method that uses a combination of the ant colony algorithm and simulated annealing (ACA-SA) for AMI networks of different sizes. The obtained results show that the path identified by the proposed method yields a shorter delay and higher throughput than paths identified using the other methods.     

COS:度量分布式大数据处理系统的效率

【目的】在大数据处理领域,分布式计算系统得到广泛应用,它们的可扩展性得到重点关注,但其绝对性能往往没有得到重视。我们希望提出科学合理、与时俱进的度量标准,对分布式系统的性能进行评估。【方法】本文通过对比特定任务的单机实现和分布式实现来讨论分布式系统的性能,提出COS(Configuration that Outperforms a Single machine)这一指标,来衡量分布式系统在达到单台机器的性能时,需要的硬件资源数量。我们选取k-means聚类和逻辑回归两个经典机器学习算法,对其进行单机多线程实现,并通过向量化计算、优化内存分配与访问等方式对性能进行了优化,为分布式多机系统的性能提供参考。【结果】以Apache Spark作为对标系统,实验发现无论是使用其原生编程接口,还是经过悉心优化的机器学习库,都要使用数倍甚至数百倍的机器,才能达到单机多线程实现的性能。【局限】分布式系统与单机实现进行性能对比并不是完全公平的,分布式系统的额外开销客观存在。【结论】但COS指标仍能反映分布式系统存在的绝对性能较差、没有充分利用硬件优势等问题。     

Better combination of thickness and hardness of mattress topper for supine sleeping posture: A physiological measurements evaluation

Placing a topper on a sleeping system is common practice to enhance sleeping comfort. The aim of this study was to determine the thickness and hardness effect of a mattress topper by measuring the four physiological measurements from 40 healthy males. The results showed that the use of a thin mattress topper (30 mm) significantly induced lower body pressure and temperature, higher muscle activities in the biceps femoris, and a straighter spinal alignment in the T12–L4 vertebrae. The use of a hard mattress topper significantly induced a higher body pressure, a lower body temperature in the lower extremities, a higher EMG (%MVC) in the trapezius, but a lower EMG (%MVC) in the biceps femoris, and a straighter spinal alignment at T1–T4, T4–T6, and T6–T8. Overall, a soft topper of 30-mm thickness was suggested as the best combination. The findings can provide very useful information for topper design and selection.     

Design of phononic materials/structures for surface wave devices using topology optimization

We develop a topology optimization approach to design two- and three-dimensional phononic (elastic) materials, focusing primarily on surface wave filters and waveguides. These utilize propagation modes that transmit elastic waves where the energy is contained near a free surface of a material. The design of surface wave devices is particularly attractive given recent advances in nano- and micromanufacturing processes, such as thin-film deposition, etching, and lithography, which make it possible to precisely place thin film materials on a substrate with submicron feature resolution. We apply our topology optimization approach to a series of three problems where the layout of two materials (silicon and aluminum) is sought to achieve a prescribed objective: (1) a grating to filter bulk waves of a prescribed frequency in two and three dimensions, (2) a surface wave device that uses a patterned thin film to filter waves of a single or range of frequencies, and (3) a fully three-dimensional structure to guide a wave generated by a harmonic input on a free surface to a specified output port on the surface. From the first to the third example, the resulting topologies increase in sophistication. The results demonstrate the power and promise of our computational framework to design sophisticated surface wave devices.     

A disruption recovery plan in a three-stage production-inventory system

This paper proposes a recovery plan for managing disruptions in a three-stage production-inventory system under a mixed production environment. First, a mathematical model is developed to deal with a disruption at any stage while maximizing total profit during the recovery-time window. The model is solved after the occurrence of a disruption event, with changed data used to generate a revised plan. We also propose a new and efficient heuristic for solving the developed mathematical model. Second, multiple disruptions are considered, where a new disruption may or may not affect the recovery plans of earlier disruptions. The heuristic, developed for a single disruption, is extended to deal with a series of disruptions so that it can be implemented for disruption recovery on a real-time basis. We compare the heuristic solutions with those obtained by a standard search algorithm for a set of randomly generated disruption test problems, and that show the consistent performance of our developed heuristic with lower computational times. Finally, some numerical examples and a real-world case study are presented to demonstrate the benefits and usefulness of our proposed approach.     

New instant confirmation mechanism based on interactive incontestable signature in consortium blockchain

The blockchain is a radical innovation that has a considerable effect on payments, stock exchanges, cybersecurity, and computational law. However, its limitations in terms of the uncertainty involved in transaction confirmation are significant. In this paper, we describe the design of a decentralized voting protocol for the election of a block generator in a consortium blockchain and propose a new system framework that allows fast and exact confirmation of all transactions. In addition, to replace a transaction’s owner signature, a new interactive incontestable signature between the dealer and owner is used to confirm a transaction. By means of this signature, the dealer can assure the owner that a transaction will be permanently included in the blockchain in a non-repudiation manner. Moreover, the signatures of all transactions in a block share only one witness that provides membership proof between the block and these transactions. Finally, a security and performance analysis shows that the proposed schemes are provably secure and highly efficient.     

Path-planning and navigation of a mobile robot as discrete optimization problems

There is huge diversity among navigation and path-planning problems in the real world because of the enormous number and great variety of assumptions about the environments, constraints, and tasks imposed on a robot. To deal with this diversity, we propose a new solution to the path-planning and navigation of a mobile robot. In our approach, we formulated the following two problems at each time-step as discrete optimization problems: (1) estimation of a robot's location, and (2) action decision. For the first problem, we minimize an objective function that includes a data term, a constraint term, and a prediction term. This approach is an approximation of Markov localization. For the second problem, we define and minimize another objective function that includes a goal term, a smoothness term, and a collision term. Simulation results show the effectiveness of our approach. This work was presented in part at the Fifth International Symposium on Artificial Life and Robotics, Oita, Japan, January 26–28, 2000