Parallel Distributed Implementation of Truss Optimization on a Local Area Network

A two-level optimization method for the design of complex truss and parallel distributed implementation on a LAN is presented using parallel virtual machine (PVM) for Win 32 as message passing between PCs. The volumes of truss are minimized by decomposing the original optimization problem into a number of bar optimization problems executed concurrently and a coordinate optimization problem, subject to constraints on nodal displacements, and stresses, buckling and crippling of bars, etc. The system sensitivity analysis that derives the partial derivatives of displacements and stresses with respect to areas are also performed in parallel so as to shorten the analysis time. The convergence and the speedup performances as well as parallel computing efficiency of the method are investigated by the optimization examples of a 52-bar planar truss and a 3 126-bar three-diraensional truss. The results show that the ideal speedup is obtained in the cases of 2 PCs for the 3 126-bar space truss optimization, while no speedup is observed for the 52-bar truss. It is concluded that (1) the parallel distributed algorithm proposed is efficient on the PC-based LAN for the coarsegrained large optimization problem; (2) to get a high speedup, the problem granularity should match with the network granularity;and (3) the larger the problem size is, the higher the parallel efficiency is.     

Geometrical design of blade＇s surface and boundary control of Navier-Stokes equations

In this article a new principle of geometric design for blade＇s surface of an impeller is provided. This is an optimal control problem for the boundary geometric shape of flow and the control variable is the surface of the blade. We give a minimal functional depending on the geometry of the blade＇s surface and such that the flow＇s loss achieves minimum. The existence of the solution of the optimal control problem is proved and the Euler-Lagrange equations for the surface of the blade are derived. In addition, under a new curvilinear coordinate system, the flow domain between the two blades becomes a fixed hexahedron, and the surface as a mapping from a bounded domain in R2 into R3 , is explicitly appearing in the objective functional. The Navier-Stokes equations, which include the mapping in their coefficients, can be computed by using operator splitting algorithm. Furthermore, derivatives of the solution of Navier- Stokes equations with respect to the mapping satisfy linearized Navier-Stokes equations which can be solved by using operator splitting algorithms too. Hence, a conjugate gradient method can be used to solve the optimal control problem.     

Topological Expression Model of Satellite Gear Mechanism

By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made.     

Operations scheduling for rail mounted gantry cranes in a container terminal yard

Arranging the retrieving sequence and making the operational plans for gantry cranes to enhance port efficiency have become vital issues for the container terminals. In this paper, the problem of retrieving containers from a yard in a given sequence is discussed as an important part of the ship-loading process. This problem is divided into three categories according to its optimization complexity, i.e., the retrieval problem of a crane with a single spreader （ACSS）, the retrieval problem of a crane with multiple spreaders （ACMS）, and the retrieval problem of multiple cranes with a single spreader （MCSS）. Firstly, heuristic algorithms are proposed to develop a retrieving sequence for ACSS to reduce the operational time. Then, optimizing the assignment to multiple spreaders is conducted by exchanging the movements of the obtained retrieving sequence. Finally, the movements are further assigned to two cranes and integrated with the MCSS retrieval problem mentioned above. The numerical experiments show the effectiveness and practicability of the heuristic algorithms.     

Distributed model predictive control with one-step delay communication for large-scale systems and a case study

A distributed model predictive control（MPC） scheme with one-step delay communication is proposed for on-line optimization and control of large-scale systems in this paper. Cooperation between subsystems is achieved by exchanging information with neighbor-to-neighbor communication and by optimizing the local problem with the improved performance index in the neighborhood. A distributed MPC algorithm with one-step delay communication is developed for the situation that there is a one-step delay in the information available from its neighbors when a subsystem solves the local optimization problem. The nominal stability is employed for the whole system under the distributed MPC algorithm without the inequality constraints. Finally, the case study of the reactor-storage-separator（RSS） system is illustrated to test the practicality of the presented control algorithm.     

Stability Analysis for Stochastic Optimization Problems

Stochastic optimization offers a means of considering the objectives and constrains with stochastic parameters. However, it is generally difficult to solve the stochastic optimization problem by employing conventional methods for nonlinear programming when the number of random variables involved is very large. Neural network models and algorithms were applied to solve the stochastic optimization problem on the basis of the stability theory. Stability for stochastic programs was discussed. If random vector sequence converges to the random vector in the original problem in distribution, the optimal value of the corresponding approximation problems converges to the optimal value of the original stochastic optimization problem.     

Numerical study on vortex induced vibration of a flexible plate behind square cylinder with various flow velocities

The vortex induced vibration （VIV） of a flexible plate behind the square head with various flow velocities is simulated. The closely coupling approach is used to model this fluid-structure interaction problem. The fluid governed by the incompressible Navier-Stokes equations is solved in arbitrary Lagrangian-Eulerian （ALE） frame by the finite volume method. The structure described by the equations of the elastodynamics in Lagrangian representation is diseretized by the finite element approach. The numerical results show that the resonance occurs when the frequency of vortex shedding from square head coincides with the natural frequency of plate. And tile amplitude of both the structure motion and the fluid load keeps increasing with the time. Furthermore, it is also found that in particular range of flow velocity the vibration of the plate would reach a periodical state. The amplitude of plate oscillating increases with the growth of velocity, while the frequency is locked.     

Three-dimensional stability analysis of excavation using limit analysis

The theory of limit analysis is presented for a three-dimensional stability problem of excavation. In frictional soil, the failure surface has the shape of logarithm helicoid, with the outline profile defined by a logspiral curve. The internal dissipation rate of energy caused by soil cohesion and gravity power of the failure soil is obtained through theoretical derivation. By solving the energy balance equation, the stability factor for the excavation is obtained. Influence of the ratio of width to height, the slope angle, and the top angle on the stability is examined. Numerical results of the proposed algorithm are presented in the form of non dimensional graph. Examples illustrate the practical use of the results.     

An Effective Hybrid Optimization Algorithm for Capacitated Vehicle Routing Problem

IntroductionVehicle routing problem(VRP)is a well-known combinatorial optimization problem and isalso a focal problem of distribution managementwithin the area of service operations managementand logistics.Capacitated vehicle routing problem(CVRP)is a very hard vehicle routing problem.The problem is to simultaneously determine theroutes for several vehicles from a central depot to aset of customers,and then return to the depotwithout exceeding the capacity constraints of eachvehicle.In prac…     

Numerical Investigation of the Dynamics for Low Tension Marine Cables

This paper presents a numerical investigation into the dynamics of marine cables which are extensively used in offshore industry. In this numerical study, the Euler-Bernoulli beam model is adopted to develop the governing equations of the cable. Bending stiffness is considered to cope with the low tension problem in local area of towing cable, and thus a more accurate solution with the consideration of the axial elongation can be given.The derived strongly-coupled and nonlinear governing equations are solved by a second-order accurate, implicit,and large time step stable central finite difference method. The quadratically convergent Newton-Raphson iteration method is applied to solving the discrete nonlinear algebraic equations. Then a towed array sonar system(TASS)problem is studied. The numerical solutions agree reasonably well with the experimental data and the simulated results of the references. The specified program of the present paper shows great robustness with high efficiency.     

基于企业套期理论的动因分析

企业套期就是企业利用金融创新产品以及远期、期货、期权与互换等金融衍生工具以消除企业在经营中所面临的一系列与收入现金流相关的不确定性所采取的策略。本文对早期企业套期理论进行了回顾，并从不完全资本市场、非对称信息与管理激励、企业资本结构等几个方面阐述了企业套期如何增加企业价值，并对企业套期理论在企业中的应用提出一些见解。     

STUDY ON CONTINUOUS-TIME HEDGING PROBLEM IN INCOMPLETE MARKETS

Introduction　　 The essence of dynamic- hedging is the abilityto replicate exactly the payoff ofa complex securityby a dynamic portfolio strategy of simpler securi-ties which is self- financing,i.e.,no cash inflowsor outflows except at the start and at the end.Ifthis strategy exists,the initial cost of the portfoliomust equal the price of the complex security.Oth-erwise,an arbitrage opportunity exists. In reality,the market is incomplete.There are institutionalrigidities,transaction costs,te…     

学术语篇中模糊限制语的人际功能研究

模糊限制语是把事物弄得模模糊糊的词语．模糊限制语是学术语篇中的常见语体特征．文章以系统功能语言学的人际功能理论和评价理论为指导,以John Weier的“Focuson Global Wanning”一文为例,分析探讨了模糊限制语在学术语篇中如何改善和维系语篇参与者之间的关系．研究表明：模糊限制语可以使学术语篇的表达更接近客观事实;可以使作者得以谨慎、谦虚地表达自己的观点,使他们易于被接受,避免招致批评;可以表达语篇参与者之间对话协商的态度．     

Price fluctuation,risk hedge and choice of optimal point

On the question of optimal hedge ratio, this paper firstly draws the chance to choose a market-entering point to the model. Using the replication principle of finance engineering, we make an assumed equity and get the optimal hedge ratio of the model, which gives the theoretical support to the practice. We should not only concern on the market-entering point, but also concern on the period of the hedge that still influences the effect of hedging. But only the period of hedging gives its affection if the time is relatively long.     

考虑运费期权的航运服务供应链优化与协调

随着全球政治、经济因素的影响,国际航运的运费费率一直处于不断变动中,投资人积极寻求金融保值工具来控制运费激增对经营带来的风险.通过引入“运费期权”的概念,本文将这一金融衍生工具运用到航运服务市场,建立了托运人收益优化模型,对其在航运服务供应链中的最优化决策进行了研究分析,经过建立对服务供应链的协调机制,使整体收益达到最优化,并通过具体算例分析对结果进行比较验证.结果表明,在采用运费期权进行套期保值交易后,航运市场中托运人存在着最优化收益决策,对整个供应链优化协调后的整体收益优于单独决策收益之和.     

选举交互模型下的股市权益定价

运用停时理论及粒子选举交互作用系统,建立了一个包含两类投资者的股票价格模型,用以描述证券市场的单只证券价格过程波动的统计特性.基于统计分析方法,证明了标准化随机价格过程收敛于相应Black-Scholes模型的分布.讨论了该价格过程模型下的欧式未定权益的定价和套期保值问题.     

中国股票市场的统计特性和期权定价

应用动力模型理论,研究和分析了实际数据（SSE和SZSE综合指数日收盘价）和模拟数据（动力模型）的收益率统计特性.发现我国股票市场的波动性与动力模型基本保持一致;还发现动力模型比正态分布能够更好的描述真实市场的对数收益率分布;在对数收益服从动力模型的基础上,应用随机理论,构造了股票价格过程;最后,通过引入风险中立概率（Risk Neutral Probability）,导出了欧式买入期权的定价公式.     

车联网信息技术高速公路预警与应急避险模型

为减少高速公路车辆追尾和连环追尾等事故,本文研究了车联网信息技术高速公路预警与避险模型.本文利用车联网系统,将交通事故快速预报给后方车辆,并实时分析路面车辆信息,帮助后方车辆及时做出合理应急方案和应急措施.试验证明,跟车预警模型能够及时提醒驾驶人员避免追尾,在无法避免正面碰撞时,应急避险模型能够根据路面状况做出有效判断,成功进行避险,避免连环追尾事故发生.公路试验中第3车减少制动距离9.2 m,第4车减少制动距离21.4 m,较大地缩减事故后续车辆行车制动距离,能够在密集的行车路段,有效降低连环追尾事故的发生,提高高速公路交通运输安全.     

一类流量增减最大值可预见的不确定网络最大流的模型与算法

不确定网络最大流问题是现实中普遍存在的一种网络流问题,针对该问题中的流在传输过程中增减并存的特征给出了一种模型及算法.将其网络上增加弧上的增加量作为初始输入量之一,经过特定运算将其转化为只损耗网络,运用有损耗网络最大流问题的算法进行最终求解.最后,通过实例验证了其正确性.     

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在对多配送中心车辆调度问题进行直观描述的基础上，建立了该问题的数学模型。提出了采用距离最近分配法将多配送中心车辆调度问题分解为多个单配送中心车辆调度问题进行求解的策略．基于求解单配送中心车辆调度问题的禁忌搜索算法，设计了求解多配送中心车辆调度问题的算法，并进行了实验计算．计算结果表明，用本文设计的算法求解多配送中心车辆调度问题，不仅可以取得很好的计算结果，而且算法的计算效率较高，收敛速度较快，计算结果也较稳定．