构建对立信号的光谱降维方法研究

针对传统的基于主成分分析的光谱降维法的缺点,提出一种新的面向颜色复制的光谱降维方 法———构建对立信号的光谱降维法（ borsd）。该方法将人 眼 视 觉 特 性 与 光 谱 线 性 降 维 模 型 相 结 合,通 过 应 用 对 立学说构建低维线性模型的前三个基向量,并用这三个基向量表征色度信息,其余基向量通过对残余光谱的主成分分析推导来增加光谱精度。实验结果表明,用 borsd 方法构建的低维线性模型相比于主成分法可在不降低模型光谱精度的情况下具有更高的色度精度和变光照下的色差稳定性.a     

Reference crop evapotranspiration determined with a modified Makkink equation

A modified version of the Makkink equation is shown to be a suitable alternative for Penman's formula for the determination of the crop reference evapotranspiration E_ref that is used in the so-called crop factor approach. Makkink's equation requires solar radiation and temperature data only. Since 1987 the Royal Netherlands Meteorological Institute has calculated E_ref with the modified Makkink's formula on a routine base. Using solar radiation derived from geostationary satellites, remotely sensed estimates of crop reference evapotranspiration can be obtained. © 1998 John Wiley & Sons, Ltd.     

硬膜下血肿的CT表现与预后

硬膜下血肿是常见的脑部外伤性病变之一。本文对我院１９８９年３月至１９９３年６月间收治的２５８例硬膜下血肿患者作了系统分析，对硬膜下血肿的ＣＴ表现与预后关系作一初步探讨。     

Curating the quest for ‘good food’: The practices,spatial dynamics and influence of food-related curation in Sweden

What is ‘good food’? Is it fair trade, local, organic or ethically produced? With an ever-expanding array of products and ‘qualities’ to consider, consumers in the global North may find it increasingly difficult and time-consuming to make the ‘right’ choices. As a result, a range of intermediaries, including food apps and collective buying groups, are emerging to support and influence people with their food choices. While intermediation refers to all activities linking producers and consumers, this paper narrows the focus and considers one important, yet poorly understood, intermediary function within the food marketplace: ‘curation’. Although the concept of curation has long been associated with museums and art worlds, curatorial practices are evolving in the contemporary marketplace and are performed by a growing range of actors operating in physical, temporary and virtual spaces. Rather than acting as brokers or gatekeepers, curators interpret, translate and shape the marketplace by sorting, organising, evaluating and ascribing value(s) to specific products. They also offer general and personalised recommendations to consumers. Although the literature on local food privileges the direct relations between producers and consumers, this paper considers the important role of intermediaries. Drawing on interviews and participant observation in Sweden it contributes to the existing literature on curation by examining the spatial dynamics and nature of curatorial practices, the motivations behind them and the values they create for consumers. The findings demonstrate that a range of activities can be understood as curation and that in order to nuance and extend existing conceptualisations of curation a wider and more dynamic range of actors (food apps), spaces (blogs) and values such as inspiration, convenience and sense of community need to be considered.     

回折波CT成像及其应用

本文评述在研究岩石圈结构时，根据已往采用广角反射波和折射波的信息进行正反演的为研究岩石圈结构。这种研究方法对那种成层性比较发育的地区效果比较好，而对于花岗岩地区或成层性不好的地区，这种方法就无能为力了。这样我们运用了回折波时间场和回折波ＣＴ成像方法相结合的系统来研究下地介质的速度结构，这种方法精度高，简单易行。并用把这种方法与以往用的正反演解释方法相比较，二者结果一致。     

Evaluating climate model outputs for hydrological applications

Citation Wilby, R. L. (2010) Evaluating climate model outputs for hydrological applications – Opinion. Hydrol. Sci. J. 55(7), 1090–1093.     

评地震危险性分析方法

本文对目前我国地震危险性分析中普遍采用的概率方法,即洪华生模型进行了分析和评述。指出上述方法忽略了断层间的相互影响;将未来大震看作小概率事件是对古登堡震级与频次关系的误解;同时,该方法中极值理论的时间概念是不可靠的。     

Spatial distribution of soil shear-wave velocity and the fundamental period of vibration – a case study of the Saguenay region,Canada

The spatial distribution of soil shear-wave velocity and the fundamental period of vibration were selected as input parameters for the determination of potential seismic site effects in the Saguenay region, Canada. The methodology used in this study involved three clear steps. First, a 3D geological model of the surficial deposits was built taking into consideration the type, spatial distribution and thickness of the deposits. Second, representative average V_s values were determined for each of the major soil units. Finally, the average shear-wave velocity from the ground surface to bedrock (V_sav), the shear-wave velocity of the upper 30 m (V_s30) and the fundamental site resonance period (T₀) were calculated over a regular grid for the study area. The results include the spatial distribution of the fundamental site resonance period, the average shear-wave velocity in the first 30 m of the ground and the spatial distribution of National Building Code of Canada seismic soil classes for the Saguenay region.     

CO2地质封存中储层流体压力演化规律的解析模型

为使解析模型可以更加科学准确地描述储层中多相流体的迁移机制与压力演化规律,提高解析计算与分析的精度。首先将储层中的流场划分为3个区域,然后根据渗流体积守恒方程反演储层中两相流体混合渗流区的各相流体饱和度,进而将总流度直接引入到达西公式中得到了一个适用于两相流的广义达西公式,据此推导出了一个更为精确的表征储层流体压力演化规律的解析模型。最后,通过案例分析,将该解析模型的计算结果与既有文献的显式积分解及TOUGH2/ECO2N的数值解进行对比,验证了该模型的可靠性及相比于既有文献的显式积分解在计算精度方面的优越性。此外,计算结果也表明,该解析模型虽然是在稳态流的假定条件下得到的,但对于实际储层流体压力演化的全过程均具有很强的表征能力,这主要归因于该模型可科学准确地确定饱和度,因此,可以在工程中推广应用。     

基于傅氏变换有限差分的三维波动方程正演模拟并行算法

傅氏变换有限差分(即FFD)混合波场延拓法波动方程正演模拟精度高,但三维FFD因其计算复杂、数据存储巨大而难以推广。这里提出三维FFD一步法正演模拟并行算法,把一个串行的大规模频率循环分割成并行的多个小规模频率循环,并发执行多个波场延拓来提高运算速度,并通过由给定的资源设定并行数,以及适时重排三维数据,大大增强了算法的适应性和时效性。通过对比并行和非并行正演实验,验证了算法的有效性。