一种电力系统在线动态安全评价模式识别法研究

文章讨论了一种应用模式识别进行电力系统在线动态安全评价的方法,利用发电机摇摆过程中转子间的最大相对摇摆角与故障前各发电机输出的有功功率之间存在的连续映射关系,用高阶多项式作为判别函数,来逼近其映射.多项式的系数用最小二乘法拟合确定,结果显示较一般方法学习简单,速度较快,更适合多个预想事故情况下共用.     

On the Magnet Effect of Price Limits

The ‘magnet’ or ‘gravitational’ effect hypothesis asserts that, when trading halts are rule‐based, investors concerned with a likely impediment to trade advance trades in time. This behaviour actually pushes prices further towards the limit. Empirical studies about the magnet effect are scarce, most likely because of the unavailability of data on rule‐based halts. In this paper, we use a large database from the Spanish Stock Exchange (SSE), which combines intraday stock specific price limits and short‐lived rule‐based call auctions to stabilise prices, to test this hypothesis. The SSE is particularly well suited to test the magnet effect hypothesis since trading halts are price‐triggered and, therefore, predictable to some extent. Still, the SSE microstructure presents two particularities: (i) a limit‐hit triggers an automatic switch to an alternative trading mechanism, a call auction, rather than a pure halt; (ii) the trading halt only lasts 5 minutes. We find that, even when prices are within a very short distance to the price limits, the probability of observing a limit‐hit is unexpectedly low. Additionally, prices either initiate reversion (non limit‐hit days) or slow down gradually (limit‐hit days) as they come near the intraday limits. Finally, the most aggressive traders progressively become more patient as prices approach the limits. Therefore, both the price patterns and the trading behaviour reported near the limits do not agree with the price limits acting as magnetic fields. Consequently, we conclude that the switching mechanism implemented in the SSE does not induce traders to advance their trading programs in time.     

Civil conflict and secessions

This paper studies secessions as the outcome of conflict between regions. We study under what conditions regions will divert costly resources to fight each other over political borders. We derive the probability of secession and the amount of resources diverted to separatist conflict, and show how those variables depend on factors such as heterogeneity costs, economies of scale, relative size, and external threats. We also model civil conflict over types of government, after borders have been determined, and study how this political conflict affects the incentives to secede. This paper has been written in memory of Herschel Grossman, and owes much to his inspiration. I am grateful to Michelle Garfinkel and David Weil, who co-organized a conference in Herschel’s honor at Brown in April 2006, for their encouragement. I thank Michelle Garfinkel and an anonymous referee for useful comments and suggestions. The usual disclaimer applies.     

信贷扶贫资金使用效率低下的原因和改革思路

我国信贷扶贫资金存在投向偏差、资金使用效率低下等问题,一方面影响扶贫的可持续性;另一方面,影响金融的可持续性,使扶贫政策效应大为削弱.本文分析了扶贫资金使用效率低下的深层次原因,提出了进行信贷扶贫方式改革的思路.     

农产品供应链与农户一体化组织引导:浙江个案

解析农产品供应链中组织形式背后的约束条件及其与农产品质量安全水平之间的关系.有助于推动我国农业产业组织创新、解决农产品质量安全问题和提高人们的生活质量与健康水平。通过对浙江省临海市上盘镇西兰花专业合作社的研究发现,没有严格的市场检测(要求),就没有一体化的组织,也就没有质量安全。因此,我国农产品质量安全管理工作的重点在于如何积极引导分散的小农户自愿形成一体化的组织。     

Impact of Carbon Dioxide Emissions Reduction on the Austrian Economy

A linked econometric input–output (IO) model of the Austrian economy with an energy block is used in this study to assess the sectoral effects of carbon dioxide emissions reduction. The energy block and the other commodities are linked by a partitioned IO model. Energy demand is described using aggregate energy demand equations, by activities and subdemand systems of the translog type for different fuel types. The conversion of energy is modelled using an IO model of the energy sector. Measures for carbon dioxide reduction from detailed expert studies are introduced in the energy model and in the econometric model. The primary impacts are on energy demand, fuel shares and investment in new energy technologies. The simulation results of the partitioned IO model show different impacts on gross output, GDP and employment.     

业主自治管理中的私人秩序

许多治理机制可以打破交易中存在的囚徒困境所带来的低效率均衡,自发的私人秩序、有组织的私人秩序和公共秩序具有互补性和替代性.城市居住小区的业主要实现有效的资源合作治理,必须让这些秩序及其组合发挥作用.由于业主自治具有公共资源管理性质,缺乏市场激励机制,因此现实中存在了种种障碍和弊端.论文主要探讨了业主内部应如何建立起私人秩序来保证合作的顺利进行.     

基于正交扩展的MB-OFDM系统性能分析

针对多带正交频分复用(MB-OFDM)通信系统存在窄带干扰的问题,提出了一种基于高阶旋转扩展矩阵的多带OFDM系统.同时用误差权重分布方法分析各种角度的高阶旋转扩展矩阵及其它正交扩展矩的分集度,并在实验仿真中比较了各种扩展矩阵对MB-OFDM系统性能的影响,结果表明各种角度(π/2除外)的高阶旋转扩展矩阵进一步提高超宽带系统抗窄带干扰的能力.     

小企业贷款业务之争——中外资银行上演尖锋对决

近年来,随着外资银行对我国金融市场渗入力度的加大,中外资商业银行之间的一场恶战已是无法避免,而尚未被国内银行充分挖掘的小企业贷款业务也必将走进中外资银行全面争夺的视野.毋庸置疑,中外资银行在这一业务的争夺上各有优劣,通过权衡它们潜在的优劣势,对中国小企业贷款业务的最终归宿做了合理展望.