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41.
    
In this paper we propose a refinement of the existing definition of volatility-induced stationarity that allows us to distinguish between processes with drift and diffusion induced stationarity and processes with pure volatility-induced stationarity. We also propose a classification of stationary processes with volatility-induced stationarity according to the volatility that is needed to inject stationarity. Processes with volatility-induced stationarity are potentially applicable to interest rate time-series since, as has been acknowledged, mean-reversion effects occur mainly in periods of high volatility. As such, we provide evidence that the logarithm of the Fed funds rate can be modelled as a local martingale with volatility-induced stationarity.  相似文献   
42.
《Economic Systems》2014,38(2):140-160
This paper tests the intra-market dynamics in a regional setting using country-specific international bonds differentiated only by maturity within individual markets in the Latin American region. We use the 2001 Argentine default as a natural experiment in this study to examine how intra-market dynamics evolved in the presence of a credit event in the region. This paper argues that emerging market instruments have a stronger tendency to tie up with instruments within markets rather than across markets as found in the literature. The long-run equilibrium relationships tend to be stronger across instruments within each market and generate economically insignificant portfolio adjustment weights. Strong interaction across instruments within markets in terms of first order dependencies has important implications for market participants, practitioners and policymakers.  相似文献   
43.
陆瑾 《价值工程》2006,25(5):37-39
典型的技术演化Logistic模型描述的是当存在两种新、旧技术的竞争时,单种创新的技术随时间的演化而扩散演化的轨迹,其缺陷是没有对多种创新技术同时作用进行分析。本文考虑一个改进的创新技术的扩散模型,拓展Logistic模型的解释空间,用技术适应度、新技术选择“尝试努力”时所运行的时间、平均尝试次数、“尝试努力”成功次数的平均概率等指标,来考察在一个固定的技术选择空间内,多种技术演化的随机寻优轨迹和寻优难度;从而在一定程度上为拓展技术选择空间引入新技术,不断进行技术创新提供理论解释。  相似文献   
44.
    
This study examines the challenges of healthcare systems toward sustainable inventory management of blood products. In this regard, three main goals are pursued; First, promoting social equity in providing medical services to various patients and reducing the risk to lives. Second, the optimal management of medical products in a way that minimizes economic costs. Third, optimal management of biological waste due to inventory corruption and reduction of greenhouse gas emissions caused by transportation, to the least environmental pollution. To achieve these purposes, a practical demand-driven multi-objective inventory model is presented by utilizing hybrid policies in an uncertain environment. In the proposed model, the demands are in two types, including elective and non-elective. These demands are classified according to their medical urgency, substitution allowance, and product freshness. A hybrid robust fuzzy stochastic programming approach is applied to capture real-world uncertainties. The proposed model is implemented for blood platelet. The solution is obtained using a combined metaheuristic technique established on genetic algorithms and simulated annealing according to global and local search paradigms. To create a proper perspective for decision-makers, sensitivity analysis is performed. Besides, the performance of the model is proved by the realization. The results show that the performance of the proposed RFSP model is better than the Nominal model. Also, it performs well in minimizing the overall system costs and environmental degradation, besides reducing shortage and wastage. It is also effective for taking steps toward equity in health and suggests a proper strategy for dealing with emergencies.  相似文献   
45.
    
We investigate the role of private and public resources in educational attainments and the socio-institutional determinants of educational resource efficiency in Italy. Following the Sen's capability approach, we consider social capital and the quality of government part of the social conversion factors through which resources can be converted into human capabilities, such as education. We analyze the case of Italy by constructing a new longitudinal dataset from 1993 to 2012, using repeated cross sections from the main social survey of the Italian Statistical Institute and a panel stochastic frontier model that takes into account endogeneity. The results show the relative importance of private resources (measured by an ad hoc constructed wealth index), the complementarity between private wealth and public expenditures on education, and the positive impact of social capital and the quality of government on educational resource efficiency.  相似文献   
46.
We consider a model in which a firm faces two types of liquidity risks: a Brownian risk and a Poisson risk. The firm chooses a dividend policy to maximize shareholder value. We characterize the optimal firm value and we show that the optimal dividend policy is a barrier strategy: the firm keeps cash inside when the cash reserves level is less than a critical threshold and pays cash in excess of this threshold. We also analyze the problem of insurance against the Poisson risk. We find that it is optimal for the firm to buy full insurance when its cash reserves are above a critical threshold and not to insure otherwise.  相似文献   
47.
    
Governments in the Asian region have been taking actions in the form of voluntary targets and policy commitments to improve the production and use of low carbon goods (LCG). However, these commitments are often challenged by many constraints, such as technological barriers and financial deficiencies. Within this context, the main objective of this study is to measure the potential of major emerging Asian economies for exports in LCG under the grand regional coalition, partial regional coalition, and standalone scenarios. The analysis indicates that emerging Asian economies will increase their export potential in LCG more under the grand coalition scenario.  相似文献   
48.
文章以我国中小企业板上市公司为研究对象,从企业经理人追求利润最大化行为出发构建中小企业的投资支出模型。不同于已有文献仅从投资-现金流敏感性角度入手的实证研究,文章的研究方法无需对样本公司进行分组,而且可以定量测度融资约束条件下的公司投资效率问题。实证结果表明:由于融资约束的存在,使得我国中小板上市公司实际投资支出最优水平低;现金流的增加不仅可以缓解融资约束压力,还能够降低融资不确定性,债务融资比例越高,融资约束越大,进一步加剧了未来融资时的不确定性;我国中小板上市公司融资约束程度与企业规模呈负相关关系,且投资效率随时间呈现下降趋势,意味着近年来我国出台的一系列旨在改善中小企业融资难的政策措施,在实践中并没有起到有效缓解融资约束的作用。  相似文献   
49.
    
Using tools from spectral analysis, singular and regular perturbation theory, we develop a systematic method for analytically computing the approximate price of a large class of derivative‐assets. The payoff of the derivative‐assets may be path‐dependent. In addition, the process underlying the derivatives may exhibit killing (i.e., jump to default) as well as combined local/nonlocal stochastic volatility. The nonlocal component of volatility may be multiscale, in the sense that it may be driven by one fast‐varying and one slow‐varying factor. The flexibility of our modeling framework is contrasted by the simplicity of our method. We reduce the derivative pricing problem to that of solving a single eigenvalue equation. Once the eigenvalue equation is solved, the approximate price of a derivative can be calculated formulaically. To illustrate our method, we calculate the approximate price of three derivative‐assets: a vanilla option on a defaultable stock, a path‐dependent option on a nondefaultable stock, and a bond in a short‐rate model.  相似文献   
50.
    
We consider a modeling setup where the volatility index (VIX) dynamics are explicitly computable as a smooth transformation of a purely diffusive, multidimensional Markov process. The framework is general enough to embed many popular stochastic volatility models. We develop closed‐form expansions and sharp error bounds for VIX futures, options, and implied volatilities. In particular, we derive exact asymptotic results for VIX‐implied volatilities, and their sensitivities, in the joint limit of short time‐to‐maturity and small log‐moneyness. The expansions obtained are explicit based on elementary functions and they neatly uncover how the VIX skew depends on the specific choice of the volatility and the vol‐of‐vol processes. Our results are based on perturbation techniques applied to the infinitesimal generator of the underlying process. This methodology has previously been adopted to derive approximations of equity (SPX) options. However, the generalizations needed to cover the case of VIX options are by no means straightforward as the dynamics of the underlying VIX futures are not explicitly known. To illustrate the accuracy of our technique, we provide numerical implementations for a selection of model specifications.  相似文献   
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