快速Hartley变换及其在图象复原中的应用

本文把快速Hartley变换引入到天文数据处理中,提出了计算Cells坐标的公式,编制了FHT算法程序。FHT与Cooley—Tukey的FFT相似,但FHT是实变换,不存在复运算,因此比FFT快得多。利用DHT与离散Fourier变换(DFT)的关系,DFT可以由FHT求出。FHT将广泛地用于谱分析,信号处理,图像处理等领域。     

激光剥蚀电感耦合等离子体质谱元素微区分析标准物质研究进展

激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)是目前地球科学分析领域的重要技术手段,元素微区分析标准物质研制是该分析技术发展的重要方向。本文对当前LA-ICP-MS元素微区分析标准物质的种类、元素分布以及应用上的优缺点和标准物质的制备方法进行了评述。现有的有证标准物质数量不多、种类不齐全,部分元素浓度较低,定值不确定度较大,应用上受到较大的局限性;研制标准也不成熟,均匀性检验方面尚未有统一的方法。本文参照岩石粉末标准物质均匀性检验方法提出了两步均匀性检验法,同时指出在标准物质种类方面,铂族元素及Au元素浓度适当、Pb-S等不同硫化物基体标准物质,以及化学成分不同的碳酸岩和磷酸岩基体标准物质是当前的迫切需求;在标准物质研制技术方面,纳米岩石粉末压片技术的研发、原位微区分析标准物质(固体)均匀性检验判别标准研究是亟待解决的问题。     

植被分布对小流域产流影响的数值实验

基于二维运动波模型,建立了一个适用于小流域场次降雨产汇流过程的动力学模型。通过对典型小流域内不同区域(坡顶、坡中及坡底区域及距离流域出口的远近)种植植被时产流过程的数值模拟,分析了小流域内植被分布对产流过程的影响。结果表明:植被分布及其特性对小流域场次降雨产流有较明显的影响;下游区域种植植被的减水效果和延滞洪峰作用优于上游区域,陡坡区域减水效果优于缓坡区域,且郁闭度越大,这种差别越明显;在该研究条件下,下游区的减水效果可达到上游区的3倍;30%郁闭度条件下减水效果可达10%和20%郁闭度条件下的3倍和1.4倍。     

应用描述词汇约简的OGC地理信息服务演绎推理

针对OGC地理信息服务在地理空间知识的有效组织和表达方面的能力比较弱,缺乏对服务信息的描述,数据丰富而知识缺乏,致使已有的数据在知识的表示和检索上存在缺陷,通过引入地理本体,按照基础地理信息要素分类,对地理信息服务的关键描述词汇进行提取,构建了地理信息服务本体库和实例数据库,应用粗糙集理论建立关键描述词汇约简模型,基于该模型实现了对地理信息服务实例数据库进行知识约简,形成最优实例数据库。最后应用地理信息服务本体库和实例数据库,基于演绎推理模型开发实例原型系统,实现了对地理信息服务对象的语义检索和推理,并通过试验从查全率和查准率两个指标验证了该方法的可行性、有效性和准确性。     

基于小波特征融合的Hyperion影像降维方法

根据影像中地物光谱曲线的小波特征点确定地物识别的合适光谱分辨率,通过融合原先若干窄波段生成具有适合地物识别光谱分辨率的宽波段数据,达到降维高光谱数据的目的。文中对hyperion影像进行坏线和Smile效应去除,经过FLAASH大气校正,得到155个波段。对提取的八类地物的样本平均光谱进行DB4小波分解,计算小波细节系数方差;以小波细节系数信息熵作为特征点,得出不可渗透表面、居民地、水田、裸土4类地物识别适宜光谱分辨率为80nm,其余地物识别适宜光谱分辨率为160nm。以窄波段间的活跃度为指标进行融合,生成降维后的宽波段分别是21个波段和11个波段。8类地物在3尺度和4尺度下的分类结果说明降维影像能满足应用需求,提出的降维方法可行。     

一种面向异常检测的高光谱图像降维算法

针对高光谱数据预处理中传统降维算法的不足,文章提出采用线性局部切空间排列(LLTSA)算法进行降维,并在低维空间中,以数据点到背景流形的最小距离为度量进行异常目标检测。面向异常目标检测问题的降维算法,需要考虑计算量和异常污染两个问题:为减少计算量,选择图像中一部分具有代表性的训练数据进行LLTSA降维并求取用于泛化的投影矩阵;为避免异常信息对背景特性的影响,应该选择不含异常的背景训练数据建立背景流形。背景训练点的选择基于递归多层分割算法,结合分割块的大小和分割块被近邻点重构的误差,去除分割结果中可能包含异常的区域并尽可能多地保留背景信息。实验结果表明LLTSA可以利用少数特征有效区分背景和异常,基于LLTSA的检测算法比经典RX和核RX算法具有更好的异常检测性能。     

Certified emissions reductions and CDM limits: revenue and distributional aspects

The EU allows those installations that are subject to emissions trading to use a limited volume of certified emissions reductions (CERs), generated through the Clean Development Mechanism (CDM), to cover their own GHG emissions. These CERs can be used in addition to the EU allowances (EUAs), which were primarily allocated free to installations in Phase II of the EU Emissions Trading Scheme (EU ETS) from 2008 to 2012. For the year 2008, the CER limits, which are differentiated by EU Member State, created substantial arbitrage rents (due to the CER-EUA spread) of approximately EU€250 million. Different options for the allocation of this rent are discussed and it is found that, according to economic theory, making the right to use CERs tradable or the regulator pre-committing to buying CERs at the level of the relevant limit reduces the inefficiencies connected to the current regulation. Furthermore, auctioning these CER usage rights shifts the rents created through the CER-EUA spread to the Member State itself. The improved design and implementation of CDM limits justifies EU policy makers intervening to correct previously competition-distorting choices.     

Living with limits: growth,resources, and climate change

Is it possible for all of humanity to enjoy the standards of living of today's high-income countries? What would happen if these limits were reached, perhaps because of climate change or a shortage of natural resources essential to production? How would society manage – or fail to manage – such limits? Notwithstanding the current financial and economic crises, these are perhaps the biggest questions confronting our species (and of a host of other species, who are the victims of our decisions). The article begins by considering the biggest economic event of our lifetimes – the ‘great convergence’ and its implications for the demand for resources. The discussion then turns to a specific limit on our development, climate change, which is different from most other limits, because it involves a global public good: the atmosphere. What such limits might mean for our civilization is discussed. One can persuade people to tackle climate change only if those concerned with the dangers persuade ordinary people that action will not come at the expense of their prosperity.     

Achieving a low-carbon society

Climate change is perhaps the central challenge that faces humanity. If the concept of green growth is to be anything more than a mere rebranding of the concept of sustainability, then it must elucidate the relationship between economic activity and pollution and provide a more detailed economic account of it. The articles in this Special Issue focus on ways in which GHG emissions may be reduced while satisfying the increasing demand for energy: from global, technological or economic solutions, to sub-national, financial or regulatory ones. Although the wide disparity in income between the least and most wealthy makes it difficult to reach a consensus on the best way to achieve a low-carbon society, the scale and potential effects of climate change make it imperative that one is reached.     

The design of California's cap-and-trade and its impact on electricity markets

California is considering the adoption of a cap-and-trade regulatory mechanism for regulating the greenhouse gas emissions from electricity and perhaps other industries. Two options have been widely discussed for implementing cap-and-trade in the electricity industry. The first is to regulate the emissions from electricity at the load-serving entity (LSE) level. The second option for implementation of cap-and-trade has been called the ‘first-seller’ approach. Conceptually, under first-seller, individual sources (i.e. power plants) within California would be responsible for their emissions, as with traditional cap-and-trade systems. Emissions from imports would be assigned to the ‘importing firm’. An option that has not been as widely discussed is to implement a pure source-based system within California, effectively excluding imports from the cap-and-trade system altogether. This article examines these three approaches to implementing cap-and-trade for California's electricity sector. The article discusses many of the issues relating to measurement and the impacts on bidding and scheduling incentives that are created by the various regulatory regimes.