汇率决定理论的发展与前沿述评

汇率决定问题是国际金融领域的一个重要命题,其间得到不断地丰富和发展。本文对汇率决定理论的发展脉络、内容、前沿作系统性地概述,并作出精要地评判。文章指出汇率行为的复杂性将是汇率决定理论研究的一个方向,非线性分析工具将成为汇率行为研究的主要手段。     

Multiple Species Boreal Forests – What Faustmann Missed

Recent research in natural sciences shows that the dynamics in boreal forests are much more complex than what many models traditionally used in forestry economics reflect. This essay analyzes some challenges of accounting for such complexity. It shows that the optimal harvesting strategy for forest owners is history dependent and for some states of the forest, more than one strategy may be optimal.This paper confirms earlier literature on shallow lakes and coral reefs and shows that this kind of phenomena seem much more common than previously thought. They are valid for a wide range of ecosystems that cover large surfaces and they do not depend on the choice of some specific function to model the non-linearity. There are also indications that theses results could be obtained even for resources with concave growth if at least one species with non-linear growth affects their dynamics.     

Asymmetric effects of industrial production,money supply and exchange rate changes on stock returns in Turkey

The aim of this article is twofold: First, it examines the asymmetric effects of industrial production, money supply and RER on stock returns in Turkey by using the non-linear autoregressive distributed lag (NARDL) model over the periods of 1994:01–2017:05 and 2002:01–2017:05. Second, it tries to determine whether there is a change of these macroeconomic variables’ effects on stock returns after the 2001 financial crisis since after 2002 period represents a structural break from the past in terms of economic, political and macroeconomic policy approaches. The study finds that the effects of the changes in industrial production, money supply and RER on stock returns are asymmetric, and the asymmetries are larger after the 2002 subsample compared to the full sample period. The empirical results further suggest that tight monetary policies appear to retard the stock returns more than easy monetary policies that stimulate them.     

Ishikawa迭代的非线性算子不动点逼近

本文在一致光滑的 Banach 空间,运用 Ishikawa 迭代,给出了方程解的逼近,进而将 C.E.Chidume 所研究结果从 Lipschitz 条件降至一致连续。关键词:巴拿赫空间;非线性算子;Ishikawa 迭代;强增生算子;强伪压缩算子;一致连续     

Persistence,mean reversion and non-linearities in the US housing prices over 1830–2013

The objective of this study is to provide a direct estimate of the degree of persistence of measures of nominal and real house prices for the US economy, covering the longest possible annual sample of data, namely 1830–2013. The estimation of the degree of persistence accommodates for non-linear (deterministic) trends using Chebyshev polynomials in time. In general, the results show a high degree of persistence in the series along with a component of non-linear behaviour. In general, if we assume uncorrelated errors, non-linearities are observed in both nominal and real prices, but this hypothesis is rejected in favour of linear models for the log-transformation of the data. However, if autocorrelated errors are permitted, non-linearities are observed in all cases, and mean reversion is found in the case of logged prices, though given the wide confidence intervals, the unit root null hypothesis cannot be rejected in these cases.     

Reluctant Generalised Additive Modelling

Sparse generalised additive models (GAMs) are an extension of sparse generalised linear models that allow a model's prediction to vary non-linearly with an input variable. This enables the data analyst build more accurate models, especially when the linearity assumption is known to be a poor approximation of reality. Motivated by reluctant interaction modelling, we propose a multi-stage algorithm, called reluctant generalised additive modelling (RGAM), that can fit sparse GAMs at scale. It is guided by the principle that, if all else is equal, one should prefer a linear feature over a non-linear feature. Unlike existing methods for sparse GAMs, RGAM can be extended easily to binary, count and survival data. We demonstrate the method's effectiveness on real and simulated examples.     

多模噪声理论及其在通信保密中的应用

给出了一种比较通用的非高斯噪声模型——多模噪声,采用无惯性非线性变换器给出了多模噪声中信号的检测与估计方法,该方法对概率密度函数形状对称的噪声是普遍适用的。在此基础上设计了可用于通信保密的多模噪声,说明了本加密方法适用于无线通信信道加密,并从统计分析的角度研究了可能的密码分析方法。     

基于非线性效应的第三方支付平台兼容性研究

本文在设定网络外部性效用为符合梅特卡夫法则的非线性函数条件下,构建双寡头支付平台兼容和不兼容两种情况下的优化模型,探讨双寡头支付平台的兼容性策略选择问题。研究发现,规模对称的双寡头支付平台兼容之后,两家支付平台的利润、消费者效用及社会福利均会增加;银联成立后中国工商银行的银行卡业务利润得以提升也验证了模型结果。建议政府借鉴银联的成功经验,使银联在线成为各支付平台的聚合型平台,提高第三方支付清算系统的效率。     

商业聚集效应的动力学分析

商业聚集促进了区域商业经济的持续增长,提升了商业企业的经济效益。聚集到底给企业带来了多大的经济效应?企业之间应该如何协调发展?通过非线性动力学建模、分析,解决了这两个实际问题,为商业企业决策提供理论参考。     

基于稀疏分解和混沌理论的微弱信号检测

针对数字锁定放大器中稀疏分解算法检测精度受限的缺点,结合非线性方法进行补偿,采用混沌检测联合稀疏分解的算法设计了数字锁定放大器。数字锁定放大器借助稀疏分解算法估计信号参数,根据估计得到的参数设计对应混沌系统;利用混沌系统检测信号的过程中产生间歇性混沌状态,并通过测量间歇性混沌状态的周期,精确检测信号。最终,在信号的信噪比低至-20 dB时可以成功检测信号,频率精度达到0.05 Hz,提供了一种非线性微弱信号检测方法。