非充分灌溉制度设计优化模型

研究了缺水地区冬小麦灌溉问题.分析了作物模型,作物水分影响函数,并以农作物产量最大为目标,提出了非充分灌溉制度优化设计二维动态规划模型和相应的动态规划逐次逼近(DPSA)求解方法.针对山东省临沂市小埠东灌区的实际情况进行研究,求得了冬小麦三个典型年不同供水水平的最优灌溉制度、排水过程及相应产量.实例表明,模型及方法是合理的.     

细纱机数据采集与处理系统

论述了细纱机数据采集与处理系统的设计思想与实现方法。     

Two attempts of study of seismic source from teleseismic data by simulated annealing non-linear inversion

Two seismic source studies usingteleseismic data are performed by Simulated Annealing(SA), a non-linear inversion method. The Very FastSimulated Annealing (VFSA) algorithm is used and onlyteleseismic data are inverted. We have designed a fastand efficient way of multiple direct problemevaluation, which is based on pre-calculating theelementary Green's function. During the process we setthe values of the inversion control parameters(temperature, number of iterations) and modified thecooling schedule. In the current version, theinversion seeks for the point source mechanism, thedepth of the source, the scalar moment and the sourcetime function (STF). The method is applied to twoearthquakes: 18 Nov. 1992 in Greece, M 5.9 and 14 Sep.1995 in Mexico, M7.3. The calculation is performed ona simple 1D model of the structure. For the firstearthquake the inversion recovered the solution fairlywell; for the second the solution was less acceptable.However, we do not consider this fact to be a failureof the method, but a consequence of an inadequatemodel of the source and of the medium structure. Acasual attempt of reliability determination was alsoperformed; the obtained values of errors arereasonable, except for a few cases when the methodfailed.     

Linux内核采用双频时钟的分析及检验

目前Linux在IBM兼容的PC上,其硬件定时器的时钟中断速率设定为100Hz,任务可以达到10ms的精度,这样低的时间精度远远不能满足实时任务的需要,如何兼顾时钟中断处理函数开销与计时精度是时钟优化必须考虑的问题.采用双频时钟机制,高低双频时钟中断,并提高内核对实时进程的响应速度,对新的时钟性能进行了分析.通过实验,测试标准Linux的时钟在不同频率下的性能及新的时钟性能.     

校院两级管理下的排课软件设计与实现

阐述了排课系统的管理层次、操作权限分配、资源管理、网络排课的具体实现过程。本系统较好地解决了多个校区、多个学院之间的分配资源和排课冲突问题。其特点是资源统一管理、分散使用,利用校园网进行教学管理,不受时间、空间的限制。     

嵌入式GIS的三维地形显示算法研究

本文论述了基于嵌入式G IS的三维地形显示的一系列理论和算法。首先介绍了三维地形显示的基本算法步骤,接下来针对嵌入式系统的特点,提出了三个改进方面,分别是递归细分、坐标变换和内存调度。在论文的最后,给出了实验结果并进行了总结。     

震后建筑进度BIM估计模型改进

传统震后建筑进度BIM估计模型,未考虑精益管理对建筑施工的影响,造成建筑成本浪费较多,影响后期建筑施工进度。本文构建基于BIM和精益管理的震后建筑进度评估模型,根据模型细分震后建筑进度评估过程,在此基础上根据BIM实施三维算量,采用进度计划编制子模型获取各分项工程量,确定建筑施工的主要进度计划,实现对建筑进度计划的编制;通过虚拟施工和现实施工两条主线,利用进度控制子模型实现对施工状态的模拟和精益管理。以此为基础,进行挣值分析比较计划施工成本、实际施工成本和挣值曲线,获取震后建筑的施工进度与成本情况。实验结果说明,本文构建的模型可对震后建筑进度和工程成本进行精准估计,能够减少成本浪费。     

乌鲁木齐国际机场时刻资源与航线布局的时空网络模式分析

航班时刻是一种无形的资源,其数量和价值与空域和机场设施资源紧密联系,是航空公司创造收益的前提和保障。深入分析航班时刻资源有助于揭示航空资源的时间空间配置模式与利用潜力。以乌鲁木齐机场为研究对象,收集航班信息数据,从定量分析的角度评价乌鲁木齐机场时刻资源与航线布局现状,以不同时段为时间单位,考察机场24 h内航班时刻资源配置结构,总结其时间结构分异特征与形成机制;从空间角度分析机场航线布局结构与时刻分异特征,重点分析机场未来面向中亚、西亚乃至欧洲境外航线布局与时刻资源分配的潜力。研究表明:航班时刻资源具有时间异质性,大致形成高峰航段、黄金航段或低谷航段等时刻类型,这与时刻分配规律、旅客出行行为习惯有关;航线布局具有空间分异特征,存在联系密集区和稀疏区,与地区间经济社会发展不平衡以及机场在省内、省外、国际市场空间中的不同作用有关,机场航线组织模式主要表现为省内以乌鲁木齐机场为中心的网状区域模式以及连接省外及国外通航城市"点对点"式航线模式。部分进出港航班时刻重叠主要集中在上午高峰航段、中午黄金航段、下午高峰航段、下午黄金航段以及晚小高峰航段,表现为这几个航段内进出港航班相对较为密集,航班进出港时刻的重叠在一定程度上受到航段划分的影响。     

地质及采矿设计过程中的几点体会

地质及采矿设计是矿山设计过程中的关键部分,它包含仔细研读原始地质资料、圈定开采境界、绘制水平分层平面图及采掘终了平面图、计算储量及剥采比、编制采剥进度计划表等,此部分的设计文件是矿山正常生产过程中的重要指导性文件。作者从自身的设计经历出发,较为详细地介绍了各环节设计过程中所应注意的技术问题,并指出了当前设计时所面临的困难,以及目前传统设计方法所面临的不足,最后结合当今国内外采矿设计的形势,对将来的发展方向进行了展望。     

Regional Variation in Mobility Levels and Timing in the United States

The age patterns of U.S. internal migration, while examined extensively at the national level, have not been fully explored at the regional scale. This study examines, using 1985 - 1990 census data, the state-level variations in two aspects of lifecycle mobility: the mobility level, or the average number of moves made over the lifecycle, and the mobility timing, or the age at which half the lifetime moves are completed. It further delineates typologies of states based upon their age structure of mobility. The study found that regional patterns in the mobility level showed some evidence of the Snowbelt-Sunbelt patterns that characterized economic restructuring in the 1980s. Geographic patterns of mobility timing were less clear; however states in the West and the South showed somewhat more young distributions than the other regions. Further, there was a statistically significant relationship between mobility levels and timing: states with higher mobility levels also exhibited older mobility profiles, as a consequence of disproportionately high elderly mobility rates. The study highlights the regional differences in mobility behavior, and the interplay between the “how much” and the “when” of mobility.