Bivariate mixed normal GARCH models and out-of-sample hedge performances

This study compares bivariate mixed normal GARCH models with standard bivariate GARCH models in terms of the percentage variance reduction of the out-of-sample hedged portfolio and also statistical significance tests of performance improvements using Superior Predictive Ability statistics. All competing models are applied to corn and wheat futures and empirical results demonstrate that the standard BEKK-GARCH model significantly outperforms the other competing GARCH models at shorter horizons. However, as the hedge horizon is extended to longer than 10 days, it is evident that the mixed normal BEKK-GARCH model is the best at the usual significance level of 5%.     

Modeling and optimizing the integrated problem of closed-loop supply chain network design and disassembly line balancing

This paper describes an integrated model that jointly optimizes the strategic and tactical decisions of a closed-loop supply chain (CLSC). The strategic level decisions relate to the amounts of goods flowing on the forward and reverse chains. The tactical level decisions concern balancing disassembly lines in the reverse chain. The objective is to minimize costs of transportation, purchasing, refurbishing, and operating the disassembly workstations. A nonlinear mixed integer programming formulation is described for the problem. Numerical examples are presented using the proposed model.     

Cooperatives, regulation and competition in Norwegian agriculture

This article analyses the efficiency of current market regulations and market structure in Norwegian agriculture. Based on their potential to coordinate farmers' supplies, large marketing cooperatives are assigned a market regulation role. However, market prices frequently tend to fall below target prices, spurring costly additional market regulations. This is not necessarily a result of inefficient coordination by the cooperative. Using a mixed market model, the study shows that over production may be explained by the competition between marketing cooperatives and investor-owned wholesalers (IOW), typically weakening the cooperatives' ability to coordinate market supply. This conclusion is robust over a variety of IOW contracts. However, to what extent competition is to blame, depends on the target price level and the contract structure of the IOW. Moreover, it is shown that current market interventions to remove excess supplies may induce further incentives to increase production.     

国有商业银行表外业务发展的现状与对策研究

改革开放以来，国有商业银行表外业务的发展取得了长足进步，但是范围还很狭窄，多以金融服务类业务为主，“或有类”业务较少，因此与西方发达国家商业银行相比差距十分明显。具体来说，存在表外业务收入占比偏低、创新能力不足、发展不平衡、管理不规范等问题，究其原因主要包括分业经营管理体制的约束、金融市场环境欠佳、市场交易主体不够成熟、银行体制改革滞后及专业人才与先进技术缺乏等。因此，国有商业银行大力发展表外业务必须深化金融体制改革、尽快实行混业经营制度。统筹规划、强化产品开发，加大科技投入和人才储备力度，实施有效市场营销策略，强化风险防范和金融监管。     

Willingness to Pay for Rural Landscape Improvements: Combining Mixed Logit and Random‐Effects Models

This paper reports the findings from a discrete‐choice experiment designed to estimate the economic benefits associated with rural landscape improvements in Ireland. Using a mixed logit model, the panel nature of the dataset is exploited to retrieve willingness‐to‐pay values for every individual in the sample. This departs from customary approaches in which the willingness‐to‐pay estimates are normally expressed as measures of central tendency of an a priori distribution. Random‐effects models for panel data are subsequently used to identify the determinants of the individual‐specific willingness‐to‐pay estimates. In comparison with the standard methods used to incorporate individual‐specific variables into the analysis of discrete‐choice experiments, the analytical approach outlined in this paper is shown to add considerable explanatory power to the welfare estimates.     

Prediction of the next hypercalcemia free period: application of random effect models with selection on first event

The length of repeated hypercalcemia free periods of patients with bone metastasis of breast cancer with at least one hypercalcemic event was modelled according to a generalized linear mixed model formulated in terms of transition probabilities and according to a latent variable model. In the former case the periods were assumed to be lognormally distributed with two variance components (patients and residue). In the latter case the conditional intensity given a patient was assumed to be the intensity of the Weibull distribution, while the random patient effect (frailty) was assumed to be drawn from a gamma distribution. In both cases the selection of only patients with at least one hypercalcemic event was taken into consideration. In both models the variance of the patient effect turned out to be negligible. For the second and later periods the Weibull appeared to fit better than the lognormal model. For the first period there was almost no information available.     

所有权与自然垄断产业规制——组合模式及选择

对于自然垄断产业采用何种所有权结构的规制模式,在理论研究与实践操作中都存在着多样化的选择。本文主要比较分析了民营外生规制、国有内生规制和混合所有权规制三种不同组合模式,并认为混合所有权规制模式较好地兼容了其他模式的优点,可以成为自然垄断产业改革与治理进程中的一个可取路径。欧盟国家自然垄断产业的改革经验,从实践上证明了混合所有权规制模式的可行性,尽管其也存在一定的局限性。同时,本文认为对于转型改革时期的中国,针对自然垄断行业的国有企业,可以考虑采用混合所有权规制模式的改革路径,通过股权开放的形式放松民营资本进入自然垄断产业的行业管制,并有效、平稳地建立起自然垄断产业规制体系。     

“逆向混改”如何影响战略性新兴产业民企绿色创新？ ——基于代表性产业比较分析的视角

以“逆向混改”现象普遍的高新技术、节能环保两类战略性新兴产业为研究对象,基于民营企业“逆向混改”的准自然实验,实证检验“逆向混改”对民企绿色创新的影响。结果显示,“逆向混改”可以有效驱动战略性新兴产业民企提高绿色创新绩效。机制检验发现,“逆向混改”具有促进专业化发展和融资约束缓解的“双重功效”,有利于促成民企绿色创新发展的“护城河”和“蓄水池”。基于代表性产业比较分析发现,环境规制的合理设计及强化,可以有效地促进高新技术产业民企“逆向混改”对绿色创新的协同效应;创新补贴政策的适度强化及激励,可以有效地促进节能环保产业民企“逆向混改”对绿色创新的互补效应。研究揭示了“逆向混改”推进民企绿色创新的影响规律,为促进战略性新兴产业高质量发展提供了理论和政策启发。     

国有股权参股与民营重污染企业绿色治理

由于生态环境投入的外部性和资本的逐利性,民营重污染企业的绿色治理是我国企业绿色治理的重点和难点.本文分析了国有股权参股对民营重污染企业绿色治理的影响机理,并以2008～2019年A股上市的民营重污染企业为研究样本进行了实证检验.研究发现,国有股权参股能够通过治理效应和资源效应促进民营重污染企业绿色治理;相对于污染风险较...     

融合改进FT显著性与Grabcut的图像目标分割算法

针对目前复杂度较大的图像中目标分割速度较慢、显著性边界分割不明确等问题,提出了一种融合改进的FT（Frequency-tuned）显著性检测与Grabcut的图像分割算法。该算法首先通过改进基于频率调谐的FT显著性检测方法得到图像中显著性较高的区域,并利用SLIC（Simple Linear Iterative Clustering）算法对显著图进行预处理得到超像素图,能够有效改善边界的分割效果,然后通过以图论GraphCut算法为基础改进的Grabcut算法建立高斯混合模型。为了提高算法效率,通过聚类以超像素代替原像素,并反复迭代高斯混合模型（Gaussian Mixed Model,GMM）参数,最后利用最大流最小割算法得到最优目标分割结果。实验结果表明所提算法能够更准确更高效率地分割图像中的显著性目标,对高分辨率图像也有很好的适用效果,相比于其他算法在分割精度上提高10%左右,并具有较高的分割效率。