Risk–Return Profiles of Islamic Equities and Commodity Portfolios in Different Market Conditions

Motivated by the recent phenomenal growth in Islamic finance and the financialization of commodities, this study makes an initial attempt to investigate the risk–return profiles of optimized portfolios combining (a) Islamic equities with commodities and (b) conventional equities with commodities during the crises and noncrises periods. The findings tend to indicate that Islamic equity–commodity portfolios provide relatively higher diversification benefits than the conventional equity–commodity portfolios during the 1997 Asian Financial Crisis triggered by the financial sector compared to the 2008 global financial crisis triggered by the real housing sector. The findings further suggest that except for a few cases, commodities in general and gold in particular improve diversification benefits.     

The spatial and temporal variation in passenger service rate and its impact on train dwell time: A time-series clustering approach using dynamic time warping

This study aims to improve the understanding of the underlying mechanism of passenger boarding and alighting processes, as well as its potential influence on train dwell time and train operation. Empirical data collected from one of busiest metro stations in Seoul, Korea, demonstrates the spatial and temporal variation in the passenger service rate, as a result of interference between boarding, alighting, and standing passengers. This study postulates that the level of interference can be associated with the train car occupancy and the proximity of train door to entry points, as waiting passengers tend to cluster near the platform entries. A unique temporal service rate curve is derived from each door location. We introduce Dynamic Time Warping for similarity assessment and clustering. It revealed four groups of train doors showing distinct shapes of curve from each platform. The first cluster includes the train doors located closest to the platform entry points where the initial service rate is drastically impeded by severe inference among passengers. The level of interference gradually diminishes as the door is located farther away from the entry points, but the overall service rate decreases as well. A passenger service time model is derived to include the cluster variable. To test its significance, the prediction capability of the model is presented with and without the cluster variable. The results of this study may be used to guide waiting passengers along the platform to minimize interference and to avoid serious disruption during passenger service time.     

Optimal excess-of-loss reinsurance contract with ambiguity aversion in the principal-agent model

ABSTRACT

We discuss an optimal excess-of-loss reinsurance contract in a continuous-time principal-agent framework where the surplus of the insurer (agent/he) is described by a classical Cramér-Lundberg (C-L) model. In addition to reinsurance, the insurer and the reinsurer (principal/she) are both allowed to invest their surpluses into a financial market containing one risk-free asset (e.g. a short-rate account) and one risky asset (e.g. a market index). In this paper, the insurer and the reinsurer are ambiguity averse and have specific modeling risk aversion preferences for the insurance claims (this relates to the jump term in the stochastic models) and the financial market's risk (this encompasses the models' diffusion term). The reinsurer designs a reinsurance contract that maximizes the exponential utility of her terminal wealth under a worst-case scenario which depends on the retention level of the insurer. By employing the dynamic programming approach, we derive the optimal robust reinsurance contract, and the value functions for the reinsurer and the insurer under this contract. In order to provide a more explicit reinsurance contract and to facilitate our quantitative analysis, we discuss the case when the claims follow an exponential distribution; it is then possible to show explicitly the impact of ambiguity aversion on the optimal reinsurance.     

不同碳排放达峰情景对产业结构的影响——基于动态CGE模型的分析

依据2017年投入产出表数据,运用可计算一般均衡理论,构建包括13个中间产业部门和5个能源产业部门的动态CGE模型,考量不同碳排放达峰情景对于产业结构的影响。结果显示：碳减排政策能促进产业结构优化,包括农业、轻工业和服务业等在内的低碳产业部门在总产出中占比增加,高耗能产业部门如非金属矿物加工业、金属加工业等在总产出中占比下降;对能源产出结构影响显著,高碳能源如煤炭、石油在能源产出比例下降,低碳能源如天然气在能源产出比例增加,其中可再生能源比例上升幅度最大。鉴此,应完善碳交易市场运行配套政策和环境,加大技术创新力度,促进产业结构和能源结构优化升级。     

Modelling economic hysteresis losses caused by sunk adjustment costs

Transition from one economic equilibrium to another as a consequence of shocks is often associated with sunk adjustment costs. Firm-specific sunk market entry investments (or sunk market exit costs) in case of a reaction to price shocks are an example. These adjustment costs lead to a dynamic supply pattern similar to hysteresis. In analogy to “hysteresis losses” in ferromagnetism, the authors explicitly model dynamic adjustment losses in the course of market entry and exit cycles. They start from the micro level of a single firm and use explicit aggregation tools from hysteresis theory in mathematics and physics to calculate dynamic losses. The authors show that strong market fluctuations generate disproportionately large hysteresis losses for producers. This could give a reason for the implementation of stabilizing measures and policies to prevent strong (price) variations or, alternatively, to reduce the sunk entry and exit costs.     

高动态临近空间飞行器海上组网测控方案设计

为解决高动态临近空间飞行器海上测控对测量船数量需求较多、现有船队规模无法满足的难题,在分析测控需求特点的基础上,提出了一种基于测量船与临近空间飞艇组网测控的新模式。结合近中程、远程飞行试验分别进行了测控总体方案设计,并讨论了海上组网测控需要研究的关键技术。相关研究对我国后续开展高动态临近空间飞行器海上测控系统建设具有一定的参考价值。     

常州装备制造业与生产性服务业动态匹配优化路径研究

装备制造业与生产性服务业动态匹配是二者之间密切互动的表现,也是二者协同发展互动升级的重要手段。通过对常州装备制造业与生产性服务业发展现状、动态匹配中存在的问题进行梳理和分析,进而从装备制造业与生产性服务业发展的中间组织的培育与促进、市场环境营造、匹配程度提升两个维度,九个方面,对两者动态匹配路径进行设计。     

动态井点降水在沈阳地铁东～滂区间盾构井的应用

地表管井动态降水在沈阳地铁东~滂区间盾构井的应用,降水井的间距、井深、泵型、下泵深度、水泵开启时间控制,通过动态调整以上参数完成盾构井基坑开挖施工。     

基于动态面板数据模型分析FDI的环境效应

外商直接投资在对中国经济增长起到积极推动作用的同时,我们也不可忽视其可能会对我国环境造成的影响。文章通过构建环境污染综合指数,并且以东中西部为三个横截面建立动态面板数据模型来分析外商直接投资对各个地区环境的影响。结果显示,外商直接投资和东部中部地区的环境污染指数之间有正相关关系,和西部地区的环境污染指数之间是一个负相关关系。