基于动态冲击试验的通勤类飞机座椅符合性验证技术

国产某型民用通勤类飞机为了取得欧洲航空安全局(EASA)型号合格证,机上座椅需进行设计更改并补充进行应急着陆情况下的动态要求符合性验证.通过对适航条款及相应标准的解读,研究了基于动态试验的航空座椅动态要求适航验证技术,其主要包括座椅动态性能基本要求、试验构型及工况筛选、试验规划、合格判据和试验结果分析等内容.结果表明,该型机旅客座椅满足适航规章对座椅的动态性能要求.该项旅客座椅动态性能试验的成功为型号取得EASA型号合格证奠定了良好的基础,该型飞机也即将成为第一个取得欧洲型号合格证的国产飞机.     

基于煤矿网络动态安全体系的安全账户管理效益分析

针对山西潞安集团潞宁煤业公司实际,在建立动态安全网络体系的基础上,构建安全账户管理体系,通过个人安全技能账户体系的构建,实行标准化考核,违章和事故大大降低,取得了预期的效益。     

英语专业教学中写作与阅读的互动模式

从ESL写作理论有关阅读和写作的相互关系出发,我国英语专业教学应加强读写教学的联系,建立读写互动模式。由读到写,从写作者角度阅读;以写促学,从读者角度写作。     

装备制造企业动态能力评价及其实证研究

阐释了装备制造企业动态能力的概念内涵与构成要素,设计出由市场感知、组织学习、资源获取、重构与转变、协调与控制5个动态能力一级指标和20个二级指标组成的评价指标体系,采用AHP法确定指标权重。针对指标度量的模糊性与不确定性,建立了证据推理的数据融合方法,并对江淮汽车集团动态能力进行了实证分析。     

Executive flight simulator as a learning tool in new companies’ resource planning based on the balanced scorecard

In many cases, a deficient strategic planning in new companies has led entrepreneurs to take inadequate initial decisions that, in the long term, reflect consequences in the failure of many new businesses. The objective of this article is to propose an executive flight simulator, which will help to identify and evaluate the different development strategies for resources of a new manufacturing company, under the four perspectives of the balanced scorecard, educating the user on the impact that these would have in the main performance indicators. The simulator is designed utilizing the focus of system dynamics to be used didactically in master's degree programs in administration, by entrepreneurs or in executive development programs.     

Iterated VaR or CTE measures: A false good idea?

The purpose of this paper is twofold. Firstly, we consider different risk measures in order to determine the solvency capital requirement of a pension fund. Secondly, we illustrate the impact of the time horizon of long-term guarantee products on these capital. We consider a financial market modelled by a common Black–Scholes–Merton model. We neglect the mortality and underwriting risks by assuming that the pension fund is fully hedged against these risks, which allows us to keep understandable and tractable formulæ (the longevity risk will be a part of future researches). A portfolio is built in this market according to different strategies and the pension fund offers a fixed guaranteed rate on a certain time horizon. We begin with well-known static risk measures (value at risk and conditional tail expectation measures) and then we consider their natural dynamic generalization. In order to be time consistent, we consider their iterated versions by a backward iterations scheme. Within the dynamic setting, we show that solvency capital can be expensive and that attention must be paid to the safety level considered.     

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.