Application of SSOR-PCGM with improved iteration format in FEM simulation of massive concrete

In this study, for the purpose of improving the efficiency and accuracy of numerical simulation of massive concrete, the symmetric successive over relaxation-preconditioned conjugate gradient method (SSOR-PCGM) with an improved iteration format was derived and applied to solution of large sparse symmetric positive definite linear equations in the computational process of the finite element analysis. A three-dimensional simulation program for massive concrete was developed based on SSOR-PCGM with an improved...     

中国崛起的认识论及其叙事衍生

从自我认同与群体归属两种需要的分析视角,作者得出了四种观察中国与非中国之间关系的视野:国家、亚洲、文明与天下。其中,从中国的角度出发,观察非中国的视野主要是国家与天下。如果继续按照自我认同与群体归属两种需要的区分,我们可得出国家权力、霸道、主权身份以及中心-边陲四种叙事的文本。简言之,看待中国崛起不是一件纯粹的客观之事,而是涉及观察者的群我关系之深层需要。中国研究不仅是一个应该适应国情并随之调整的方法论问题,而且它还涉及知识形成的前提,亦即中国与非中国关系所涉及的群我关系。群我关系的形成与认知须靠文化形塑,进而使行为主体形成对中国崛起的认识角度与文本选择。     

工厂化农业园区企业竞争力分析

在对我国工厂化农业企业发展及其竞争力状况进行分析的基础上,提出一方面要考虑我国的劳动力优势,另一方面要注重实施非核心技术创新和运行机制等非技术创新,提高我国工厂化农业企业的竞争力。     

潮汐电站月周期优化调度模型及其应用

在分析单库双向潮汐电站运行特点的基础上，以月发电量最大为目标建立电站优化调度模型，进行了动态规划描述，计算了江厦潮汐电站月最大发电量。与实际月发电量比较后表明，该优化调度模型合理有效。     

APPLICATION OF LBM-SGS MODEL TO FLOWS IN A PUMPING-STATION FOREBAY

A 2-D Lattice Boltzmann Method (LBM) coupled with a Sub-Grid Stress (SGS) model is proposed and validated by flows around a non-submerged spur dike in a channel. And then the LBM-SGS model is further applied to flows in a pumping-station forebay. Shallow water equations are numerically solved by the LBM and the turbulence can be taken into account and modeled efficiently by the Large Eddy Simulation (LES) model. The bounce-back scheme of the non-equilibrium part of the distribution function is used at the inlet boundary, the normal gradient of the distribution function is set as zero at the outlet boundary and the bounce-back scheme is applied to the solid wall to ensure non-slip boundary conditions. Firstly, the model successfully predicts the flow characteristics around a spur dike, such as circulating flow, velocity and water depth distributions. The results are verified by the experimental data and compared to the results obtained by conventional Smagoringsky Model (SM) of LES. Finally, the LBM-SGS model is used to further predict the flow characteristics in a forebay, such as secondary flow and water level. The comparisons show that the model scheme has the capacity to simulate complex flows in shallow water with reasonable accuracy and reliability.     

广西农村劳动力素质面临的问题及对策

广西是农业大省区,农村人口占绝大多数,这就决定了广西要实现全面建设小康社会的目标,必须把重点放在农村。广西作为我国经济发展相对滞后的地区,也是我国农村建设过程中面临问题最多最迫切需要解决的地区。本文就西部地区的广西的劳动力素质所面临的问题进行了分析,并提出了相应的对策,这对于实现全面的小康社会,构建和谐社会,建设社会主义新农村仍有着深远的现实意义。     

Program Evaluation and Review Technique (PERT) in Construction Schedule Risk Assessment

Construction project scheduling is one of the most critical factors for project success measurement.Not only for the project planning but for construction process management,the scheduling is the basic tool for communication between the owner and the project manager.By developing the schedule before the project starts,the owner knows in advance that the expected timeline of the project.By preparing construction process scheduling,the owner and general contractor can better manage the subcontractors,sub-trades progress,materials storage and deliveries,labors schedule and equipment set up which will eventually save time,money and hassle.Basically,Critical Path Method(CPM) is commonly used in the construction industry.CPM is a deterministic method that assumes that through the network,there is at least one path that determines the project duration and that the path is the critical path.CPM does not consider the uncertainty in the activities;rather it assumes that each activity can be finished in the given situation.Program Evaluation and Review Technique(PERT) is a stochastic technique which is based on the assumption that the duration of a single activity can be described by a probability density function.PERT takes into account the uncertainty during the construction process and has been created out of the need to plan,schedule and control complex projects with many uncertainties.The PERT approach is stated in some books and papers,but there is no deep investigation on the application in the schedule risk assessment.This paper investigates the PERT work process and takes a valuable try on the construction schedule risk assessment by using case studies.The utilization in the estimate the construction liquidated damage with the uncertainties is performed,which also can be used in the insurance company to calculate the insurance premium.     

THE OPTIMAL DESIGN BASED ON RELIABILITY OF WATER DISTRIBUTION SYSTEM BY LINEAR MODEL

In this paper, a new technique are developed for optimal design of water distribution system besed on reliability. It applies a linear programming algorithm to the optimal design based on reliability. Within a small optimal search step range,the objective function and constraints can be expressed in the first order Taylor-expanding form,and three sub-models (a steady-state simulation model, a reliability model and a linear optimization model) are linked each in optimal searches. Thus, a traditional non linear problem can be solved by a linear model, the computing burden is significantly decreased. Therefore, the linear optimal model developed by the paper has more practical significance.     

基于人工神经网络的大坝变形分析与预报研究

本文在分析大坝位移影响因子的基础上,给出了基于BP-ANN(人工神经网络)分析大坝变形时的七种输入模式。探讨了在建立BP-ANN模型时几个关键问题的处理方法。结合某一混凝土拱坝的垂线观测数据,应用BP-ANN的不同输入模式,对大坝的变形值进行了预报和分析,得出了一些有益的结论。     

HYDRAULIC RESISTANCE OF SUBMERGED VEGETATION RELATED TO EFFECTIVE HEIGHT

Submerged vegetation has a significant impact on water flow velocity. Current investigations include the impact through adding drag resistance and increasing bottom roughness coefficient, which cannot elucidate the characters of real submerged vegetation. To evaluate the effects of submerged vegetation on water currents at different velocities, a laboratory experiment was conducted using three kinds of vegetations. The effective heights of these vegetations on varying flow velocities were evaluated. An equation describing the relationship between the normalized resistance of the submerged plants and the Reynolds number based on the plant effective height was then established and used to calculate the hydraulic resistance parameters of submerged plants in different stages of growth.