Moving or Leaving

Abstract

Difficult decisions about the collection had to be madeby the library staff planning the moveto thenew Walter C. Koerner Library at the University of British Columbia. Thislibrary wasto bethe center for servicesto Humanities and Social Sciencesusers, but could accommodate only 60% of the Humanitiesand Social Sciences collectionshoused in the old Main Library. The staff had to decide what parts of the collection to move and what to leave in the old building, against the day when the second phase of the Koerner Library should be built. This article describes howthese difficult choices were made, including the consultation process, the development of criteria to split the collection, and their implementa-tion.     

20世纪30年代梧州省立医院巡诊县乡的医疗实践

20世纪30年代之初,广西全省除邕桂梧等城市设有教会医院或诊所外,稍具规模的公立医院仅有梧州省立医院一所,广大居民缺医少药。梧州省立医院并不偏安于城市,而是认识到乡村医药更形匮乏,乡民需要医药更甚。因此,有组织巡回医队之举,为无医无药的乡村带去医药及其知识,诊治与预防部分乡民的疾病。城市医院医生自愿深入乡村,这与当时西洋医学在通商大埠"资产阶级化"的倾向相比,更体现着梧州省立医院医生眼光向下的精神。     

基于移动平均-马尔可夫链模型的上海市机场旅客吞吐量预测研究

为了更多的挖掘数据的信息,本文将移动平均与马尔可夫链模型结合,对马尔可夫链模型进行改进,以拟合结果为动态基准线来构建动态的马尔可夫链,并进行预测及平稳分布研究.利用上海市机场2008年1月至2013年10月的各月数据进行模型拟合,将拟合结果作为动态基准线,进行系统状态划分,确定状态转移概率矩阵.预测未来4个月的中值和区间,并根据马尔可夫链的遍历性和稳定性求出状态的平稳分布.实证表明,该方法的预测精度更高,并且具有较强的适用性和泛化性,具有较强的实用价值.     

Kalman滤波器在单运动目标自动跟踪中的应用

在系列帧图像中对运动目标以直方图为模型的模板方法进行匹配,由于模板匹配计算量非常大,要想在整幅图像中对目标进行搜索匹配,同时又要达到实时是不可能的。我们对目标状态进行可靠的估计,可以在相对较小的区域内完成对模板的搜索,Kalman滤波器就是一个对动态系统的状态序列进行线形最小方差估计的算法。通过以动态的状态方程和观测方程来描述系统,它可以将任意一点作为起点开始观测,采用递归滤波的方法计算。该算法具有计算量小、可实时计算的特点。     

双运动原子与单模光场相互作用系统的原子布居数演化特性

运用全量子理论研究单模光场与双运动原子相互作用系统的原子布居演化规律,结果表明,原子布居数振荡的频率随原子运动速度和光子数的增大而增大,振幅随原子运动速度和光子数的增大而减小。     

一种基于直方图的实时自适应阈值分割方法

在视频序列图像中,视频图像分割的主要目的是要在视频序列中分割出运动实体,背景差法能够在实时性要求很高的情况下从一段视频中将当前帧图像跟背景图像作差,然后提取出运动目标,而对差图像进行二值化是关键,自适应阈值方法通过对差图像的直方图进行分析寻找直方图上的一个点,该点到直方图最高点与最低点之间的线段的距离最大,为求该点,本文提出了一种快速算法,以该点对应的灰度值作为阈值,这样运动目标就能够被精确地提取出来.     

数控高速切削加工中刀具路径的研究

数控高速切削加工与普通数控加工不同,具有其独特的性质,所以对刀具路径的规划也有着更高的要求,主要为以下几点：保持最大和稳定的切削速度;避免不连续和突然的加速度变化;刀具运动保持恒定的进给速度,产生相同体积的切屑;在保持插值公差的前提下,尽可能减少程序段数：提供高度连续的光滑的刀位数据。所以刀具路径规划主要是对铣削方向、进退刀方式、移刀方式、走刀方式、拐角处理等方面进行研究。本文仅以UG NX3．0为例对数控高速切削加工的刀具路径进行研究。     

当前篮球控球后卫不定区域移动式组织进攻方法分析

通过研究美国NBA 比赛控球后卫的组织进攻形式, 发现一种新的组织进攻方法———控球后卫不定区域移动式组织进攻方法。这种进攻形式有其鲜明的特点, 并对控球后卫有较高的能力要求, 具有较大的发展空间。     

Theoretical and experimental studies of heat transfer with moving phase-change interface in freezing and thawing of porous potting soil

Soil in a cold region is subject to frequent freezing and thawing cycles. Soil frozen for a prolonged period may cause adverse freeze damage to the plants due to cell dehydration or root cell rupture. It is important to understand the detailed heat transfer behaviors of the freezing and thawing processes to prevent freeze damage, and to devise proper mitigation measures for effective pot planting in cold regions. A theoretical model was developed to analyze the transient moving phase-change interface heat transfer in the freezing and thawing of porous potting soil. The theoretical derivation is based on the assumption that the soil freezes completely at a single temperature. Microscopic poromechanic effects on heat transfer behavior were ignored. The spatial domain of the problem was simplified to a 1 D spherical coordinate system with variation in the radial direction. Green＇s function was applied to solve for the time-dependent body temperature. Experiments were conducted for validation of the theoretical model Reasonable agreement between the theoretical predictions and experimental measurements was obtained. The theoretical model developed can be easily used to determine the sensitivity of various parameters in the freezing/thawing processes, e.g., thermal properties of soil, ambient temperature, and planting pot size.