EMPIRICAL PERFORMANCE OF GARCH MODELS WITH HEAVY‐TAILED INNOVATIONS

We introduce a new type of heavy‐tailed distribution, the normal reciprocal inverse Gaussian distribution (NRIG), to the GARCH and Glosten‐Jagannathan‐Runkle (1993) GARCH models, and compare its empirical performance with two other popular types of heavy‐tailed distribution, the Student's t distribution and the normal inverse Gaussian distribution (NIG), using a variety of asset return series. Our results illustrate that there is no overwhelmingly dominant distribution in fitting the data under the GARCH framework, although the NRIG distribution performs slightly better than the other two types of distribution. For market indexes series, it is important to introduce both GJR‐terms and the NRIG distribution to improve the models’ performance, but it is ambiguous for individual stock prices series. Our results also show the GJR‐GARCH NRIG model has practical advantages in quantitative risk management. Finally, the convergence of numerical solutions in maximum‐likelihood estimation of GARCH and GJR‐GARCH models with the three types of heavy‐tailed distribution is investigated.     

高端乡村旅游产业与生态环保基础设施协同发展研究——以天津蓟州区为例

在经济新常态下积极推动发展高端乡村旅游产业已经成为我国建设美丽乡村的重要着力点,与此同时"反生态"问题的不断显现已成为阻碍我国乡村旅游经济实现可持续发展的掣肘,因此,高端乡村旅游产业的发展模式向生态化转型势在必行。以天津市蓟州区乡村旅游景区的环保基础设施为研究对象,从环境情况、设施配备和从业人员3个方面确定了20个影响因素,通过向游客发放问卷进行满意度调查,从游客感知角度的基础上采用IPA模型分析游客对景区环保基础设施的重要性和满意度。结果表明,准则层及指标层感知均值都为游后感知实绩(满意度)<游前期望(重要性),在此基础上提出用冲突协同理论来指导蓟州区高端乡村旅游产业发展中的环境管理工作,实现高端乡村旅游产业与环保基础设施的协同发展,也能为今后的相关研究奠定基础。     

The effect of diplomatic representation on trade: A panel data analysis

This study addresses current gaps in the empirical literature regarding the effect of diplomatic representation on trade using a panel data set for 100 countries with 5‐year interval data from 1985 to 2005 and four‐digit level industry data. The results indicate that the effect of diplomatic representation on exports in differentiated goods is positive and significant and larger than on exports in homogeneous goods on average, but not statistically different from it. Furthermore, diplomatic representation only increases trade along the extensive margin and not along the intensive margin. The results indicate that diplomatic representation is effective in performing its function as a network search intermediary and that it is a useful policy tool to alleviate market failure.     

ERP与MRO系统集成过程建模与应用研究

为了实现产品生产阶段到服务阶段业务与数据的有效集成,从业务层和数据层对制造服务系统中的大修维护维修(MRO)与企业资源计划(ERP)的集成过程进行了建模与分析,对ERP与MRO系统之间的业务过程和信息交互过程进行了分析,建立了二者的业务集成框架模型,分析了ERP与MRO系统的数据结构转换过程,提出了二者数据集成模型。应用Web Services完成了ERP与MRO的系统集成开发,包括服务BOM集成、备品备件管理集成等。研究结果实现了制造和服务阶段关键产品数据信息的集成与反馈,打通了从制造到服务阶段的数据传递与集成,对进一步研究复杂产品生命周期管理的信息集成具有一定的借鉴意义。     

Evaluating discounts as a dimension of customer behavior analysis

Today, increased competition between organizations has led them to seek a better understanding of customer behavior through identifying valuable customers. Customers’ expectations about the price and quality of products and services play an important role in their selection process. In online businesses, competition and price differences between suppliers is high, so discounts will attract different customers. As a result, discounts and the frequency and amount of purchases can lead to better understanding of customer behavior. Customer segmentation and analysis is essential for identifying groups of customers. Hence, this study uses a model based on RFM called RdFdMd, in which d is the level of discount used to analyze customer purchase behavior and the importance of discounts on customers’ purchasing behavior and organizational profitability. The CRISP-DM and k-mean algorithm were used for clustering. The results indicate that using the R_dF_dM_d model achieves better customer clustering and valuation, and discounts were identified as an important criterion for customer purchases.     

Macroeconomic Uncertainty in South Africa

This paper develops a new index of economic uncertainty for South Africa for the period 1990–2014. The index is constructed from three sources: (1 ) Disagreement among professional forecasters, (2 ) a count of international and local newspaper articles discussing economic uncertainty in South Africa and (3 ) mentions of uncertainty in the quarterly economic review of the South African Reserve Bank. The index shows high levels of uncertainty around the period of democratic transition in 1992–1994, the large depreciation of the currency in 2001 and the financial crisis of 2008. The uncertainty index is a leading indicator of a recession. An unanticipated increase in the index is associated with a fall in GDP, investment, industrial production and private sector employment. Contrary to evidence for the U.S.A and the U.K., uncertainty shocks are inflationary. These results are robust to controlling for global uncertainty shocks, consumer confidence and financial shocks.     

Assessing cost‐effectiveness when environmental benefits are bundled: agricultural water management in Great Barrier Reef catchments

Using economic analysis to prioritise improvements in environmental conditions is particularly difficult when multiple benefits are involved. This includes ‘bundling’ issues in agricultural pollution management, where a change in management action or farming systems generates multiple improvements, such as reductions in more than one pollutant. In this study, we conceptualise and compare two different approaches to analysing cost‐effectiveness when varying bundles of benefits are generated for a single project investment. Each approach requires data to be transformed in some way to allow the analysis to proceed. The index approach requires the transformation on the benefits side so that the effects of multiple pollutant changes can be combined into a measure for each project which can then be compared to costs. By comparison, the disaggregation approach requires the transformation on the costs side where costs for each project have to be apportioned across the different pollutants involved. The paper provides novel insights with an application to agricultural water quality improvements into the Great Barrier Reef in Australia, demonstrating that while both approaches are effective in prioritising projects by cost‐effectiveness, the disaggregation approach provides more insightful results and values that may be relevant for use as upper value guidelines in future project selection.     

Semistatic hedging and pricing American floating strike lookback options

We price an American floating strike lookback option under the Black–Scholes model with a hypothetic static hedging portfolio (HSHP) composed of nontradable European options. Our approach is more efficient than the tree methods because recalculating the option prices is much quicker. Applying put–call duality to an HSHP yields a tradable semistatic hedging portfolio (SSHP). Numerical results indicate that an SSHP has better hedging performance than a delta-hedged portfolio. Finally, we investigate the model risk for SSHP under a stochastic volatility assumption and find that the model risk is related to the correlation between asset price and volatility.     

Covariance breakdowns and connectedness of crude oil futures markets with non-synchronous data

ABSTRACT

This article identifies the breakdowns in the covariance of three benchmark crude oil futures markets (WTI, Brent and Dubai) and investigates the changes of market connectedness across the breakdown periods. As the crude oil futures are traded in different regions, this article eliminates the non-synchronous trading data by employing the Vector Moving Average structure and the Bayesian data augmentation approach, which keeps the integrity of original data without changing its properties. The results show that there are significant breaks in the covariance structure of crude oil futures markets. The breakdown periods are consistent with the periods when the market volatilities are at high level and the returns are volatile. The changes of market connectedness are independent of the covariance states, which supports the globalization hypothesis for the crude oil market. The results also suggest that there is more information flow out of the WTI than to the WTI during the sample period, particularly during the breakdown periods in 2008–2009.     

Cost comparison of continued anticoagulation with rivaroxaban versus placebo based on the 1-year EINSTEIN-Extension trial efficacy and safety results

Aims: The EINSTEIN-Extension trial (EINSTEIN-EXT) found that continued treatment with rivaroxaban for an additional 6 or 12 months (vs placebo) after 6–12 months of initial anticoagulation significantly reduced the risk of recurrent venous thromboembolism (VTE) with a small non-significant increased risk of major bleeding (none fatal or in critical site). This study aimed to compare total healthcare cost between rivaroxaban and placebo, based on the EINSTEIN-EXT event rates.

Methods: Total healthcare cost was calculated as the sum of treatment and clinical event costs from a US managed care perspective. Treatment duration and event rates were obtained from the EINSTEIN-EXT study. Adjustment on treatment duration was made by assuming a 10% non-adherence rate. Drug costs were based on wholesale acquisition costs. Cost estimates for clinical events (i.e. recurrent deep vein thrombosis [DVT], recurrent pulmonary embolism, major bleeding, clinically relevant non-major bleeding) were determined from the literature. Results were examined over a ±20% range of each cost component and over 95% confidence intervals (CIs) of event rate differences in deterministic (one-way) and probabilistic sensitivity analyses (PSA).

Results: Total healthcare cost was $1,454 lower for rivaroxaban-treated (vs placebo-treated) patients in the base-case, with a lower clinical event cost fully offsetting drug cost. The cost savings of recurrent DVT alone (–$3,102) was greater than drug cost ($2,723). Total healthcare cost remained lower for rivaroxaban in the majority (73%) of PSA (cost difference [95% CI]?=?–$1,454 [–$2,396, $1,231]).

Limitations: This study was conducted over the 1-year observation period of the EINSTEIN-EXT trial, which limited “real-world” applicability and examination of long-term economic impact. Assumptions on drug and clinical event costs were US-based and, thus, not applicable to other healthcare systems.

Conclusions: Total healthcare costs were estimated to be lower for patients continuing rivaroxaban therapy compared to those receiving placebo in VTE patients who had completed 6–12 months of VTE treatment.