Selection of resilient supply portfolio under disruption risks

This paper deals with the optimal selection and protection of part suppliers and order quantity allocation in a supply chain with disruption risks. The protection decisions include the selection of suppliers to be protected against disruptions and the allocation of emergency inventory of parts to be pre-positioned at the protected suppliers. The decision maker needs to decide which supplier to select for parts delivery and how to allocate orders quantity among the selected suppliers, and which of the selected suppliers to protect against disruptions and how to allocate emergency inventory among the protected suppliers. The problem objective is to achieve a minimum cost of suppliers protection, emergency inventory pre-positioning, parts ordering, purchasing, transportation and shortage and to mitigate the impact of disruption risks by minimizing the potential worst-case cost. As a result a resilient supply portfolio is identified with protected suppliers capable of supplying parts in the face of disruption events. A mixed integer programming approach is proposed to determine risk-neutral, risk-averse or mean-risk supply portfolios, with conditional value-at-risk applied to control the risk of worst-case cost. Numerical examples are presented and some computational results are reported.     

Dynamic Impacts of a Catastrophic Production Event: The Foot‐and‐Mouth Disease Case

In foot‐and‐mouth disease (FMD) free countries, the occurrence of an FMD outbreak is a rare event with potentially large economic losses. We explore the dynamic effects of an FMD outbreak on market variables and economic surplus taking into account the largely neglected issue of farm bankruptcy. Simulations are performed on a stylized agricultural economy, which is a net exporter before the outbreak. We find complex dynamic market effects when the farm credit market suffers from information imperfections leading to farm closure. Welfare effects are also dramatically altered. Domestic consumers may lose in the long run from an FMD outbreak because domestic supply contracts. On the other hand, farmers able to resist this event may ultimately gain. Our analysis also shows that these effects are not monotone, making any efficient policy response to this catastrophic event quite challenging.     

Exact inference for a simple step-stress model with competing risks for failure from exponential distribution under Type-II censoring

In reliability analysis, accelerated life-testing allows for gradual increment of stress levels on test units during an experiment. In a special class of accelerated life tests known as step-stress tests, the stress levels increase discretely at pre-fixed time points, and this allows the experimenter to obtain information on the parameters of the lifetime distributions more quickly than under normal operating conditions. Moreover, when a test unit fails, there are often more than one fatal cause for the failure, such as mechanical or electrical. In this article, we consider the simple step-stress model under Type-II censoring when the lifetime distributions of the different risk factors are independently exponentially distributed. Under this setup, we derive the maximum likelihood estimators (MLEs) of the unknown mean parameters of the different causes under the assumption of a cumulative exposure model. The exact distributions of the MLEs of the parameters are then derived through the use of conditional moment generating functions. Using these exact distributions as well as the asymptotic distributions and the parametric bootstrap method, we discuss the construction of confidence intervals for the parameters and assess their performance through Monte Carlo simulations. Finally, we illustrate the methods of inference discussed here with an example.     

论寿险经营风险的防范和控制

寿险经营 ,实质上是一种负债经营 ,而且由于寿险风险具有隐藏性、累积性、爆发性和危害性的特点 ,一旦爆发 ,就可能造成严重的社会后果 ,这就需要寿险公司及其监管机构及早识别寿险经营中存在的风险 ,进行防范和控制 ,以维持寿险经营的稳定。本文从防范和控制寿险经营风险的必要性出发 ,分析了寿险经营中存在的各种风险 ,尝试运用财务分析法中的各种指标测试来识别这些风险 ,提出了监管机构、寿险公司和自律组织在寿险经营风险防范和控制中应采取的各种措施。     

论我国股票市场的运行效率

股票市场的效率在于能够最大限度地融集资金并在产业和企业间进行有效分析；能够提供资金最大流动性，降低股票交易的成本，实现资源的有效配置。为此，必须从提高股票市场的效率入手，尽快完善我国股票市场的运行机制，使股票市场充分发挥资源配置和分散风险两大功能。     

Do Drivers of Small Cars Take Less Risk in Everyday Driving?

Previously reported observed data on risky everyday driving are brought together and reanalyzed in order to focus on the relation between risky driving and the size of the car being driven, as indicated by car mass. The measures of risky driving include separation between vehicles in heavy freeway traffic and speed on a two lane road. Observed seat belt use provides a third measure of driver risk. Confounding effects arising from the observed association between car mass and driver age are taken into account by segmenting the data into three driver age groups. Driver risk taking is found to increase with increasing car mass for each of these three aspects of everyday driving. The implications of these results with respect to driver fatality rates are discussed in terms of a simple model relating observed risky driving to the likelihood of involvement in a severe crash.     

Expanded renal transplantation: a competing risk model approach

Multi-state models (MSMs) are useful to analyze survival data when, besides the event of main interest, one or more intermediate states of the individual are identified. These models take the several existing states and the possible transitions among them into account. At the same time, covariate effects on each transition intensity may be investigated separately and, therefore, MSMs are more flexible than the standard Cox proportional hazards model. In this work, we use MSMs to investigate the impact of the quality of a transplanted kidney for a group of patients at the Hospital Universitario Central de Asturias. Specifically, we use an illness-death model to study the evolution of patients with kidney disease who received a renal transplant after a dialysis period. The intermediate state is defined as the failure of the received organ, while the terminating state is the death of the patient. In order to increase the potential number of organs available for transplant, the standards of quality for the transplanted kidneys were relaxed (the new criteria are labeled expanded criteria), and these ‘expanded kidneys’ were transplanted in appropriate candidates (older patients, with higher prevalence of diabetes mellitus). Results suggest that the expanded kidneys have a minor effect on survival, while both the kidney mortality and the risk of death increase with the patient's age and the serum creatinine and serum hemoglobin levels.     

Computation of Sharp Bounds on the Expected Value of a Supermodular Function of Risks with Given Marginals

We show that the rearrangement algorithm (RA) introduced in Puccetti and Rüschendorf (2012 Puccetti, G., Rüschendorf, L. (2012). Computation of sharp bounds on the distribution of a function of dependent risks. Journal of Computational and Applied Mathematics 236(7):1833–1840.[Crossref], [Web of Science ®] , [Google Scholar]) to compute distributional bounds can be used also to compute sharp lower and upper bounds on the expected value of a supermodular function of d random variables having fixed marginal distributions. Compared to the analytical methods existing in the literature the algorithm is widely applicable, more easily obtained and gives insight into the dependence structures attaining the bounds.     

论我国保险资金的运用及对策

保险业作为服务于社会生产和生活的第三产业 ,以组织后备资金形式为国民经济的发展提供风险保障。虽然中国保险业资金运用方面存在着保险资金运用渠道较窄、保险公司资产面临较高利率风险、保险资金运用中短期行为严重等问题 ,在很大程度上与当今中国保险市场发展实践和保险业经营运作趋势不适应 ,但可以通过修改《保险法》 ,提高资金运用收益率以明确资金运用方式、范围 ;通过建立专业化资金运用体系 ,提高专业化经营水平和风险监督机制 ;为保险资金运用拓宽渠道 ,提高资金运用的安全性。     

The ‘Bakul Gendong’ as a communication strategy to reject the construction of a cement factory in Central Java

Since 2006, one of Indonesia’s biggest corporations operating in the cement industry has been trying to build a factory at Sukolilo village in Central Java, Indonesia. The potential for of environmental damage caused by mining and the construction of this new factory is the main source of conflict between the public and the giant corporation.The focus of this research was the communication strategy adopted by women in the community to reject the construction of the cement factory in Pati, Central Java, Indonesia. This research used a qualitative method through a case study approach. Interviews, observations, and literature studies were used as data collection techniques for in this research.We found that the practices of the “Bakul Gendong” communication strategy were effective in developing women’s awareness of environmental issues based on the values they believe in. Through the women peddlers, women’s awareness of the risk of environmental damage caused by the cement factories was successfully developed. They also created female farmers’ group named “Simbar Wareh” to strengthen cooperation between them and to better-organize their resistance. The women’s movement to resist the cement factory was also conducted by building a network, meeting authorities, demonstrating, displaying traditional symbols during celebrations such as the “Agustusan” (independence day celebration) and Kartinian (women’s day) as their sites of resistance. The local government and PT. Semen Gresik tended to use technical and economical communicative approaches, while the people mainly refer to local know how PT. Semen Gresik did not use the right communication strategy to understand the conflict that arose and how to handle it, until after 10 years of trying to build a factory in Sukolilo.