Nonlinear dynamical systems and inventory management

Surprisingly, deterministic time series can generate highly irregular, random-appearing trajectories. These deterministic time series result from nonlinear dynamical systems of differential or difference equations. The random appearance displayed by these systems is called nonlinear dynamical complexity. Properties of nonlinear complex systems include aperiodic random appearance, sensitive dependence on initial conditions and model parameters, and nonstationarity. Experiments involving the operation of simulated business environments and theoretical nonlinear dynamical models for inventory are reviewed to explore motivating factors that can give rise to demand with nonlinear complexities. The experimental and theoretical evidence reviewed indicates that nonlinear complexities in demand have significant implications for inventory management. Thus, researchers and practitioners in inventory management need to consider these properties when choosing inventory management methods. Characteristics of nonlinear dynamical systems and their implications for inventory management are presented in this paper. The use of the Brock, Dechert, and Scheinkman (1987) (BDS) test for nonlinear dependence is demonstrated on actual demand data.     

Prediction of decomposition limits for ethylene oxide-nitrogen vapor mixtures

A decomposition limit equation applicable to liquid ethylene oxide storage conditions based on recently obtained data is presented. Comparison is made with a second correlation equation developed from literature data. Adjustment of predicted decomposition limits to produce recommended safe operating limits is discussed.     

伦敦交通拥挤的代价

本文通过描述伦敦交通拥挤收费制的起源以及现实中如何克服理论和实践层面的两难实施过程,对道路收费所引致的各种效应进行了论证.作者认为伦敦交通拥挤收费制的引入,应该归功于经济学的贡献,道路定价行动在克服交通拥挤的外部性上,不过是一种应对公众和政治利益诉求的适宜性政策回应.     

Measuring the dynamics of APEC output connectedness

We examine the dynamics of output connectedness of Asian Pacific Economic Cooperation (APEC) economies using time‐varying, region‐specific, generalised connectedness measures. We find that the connectedness of APEC economies with the rest of the world is quite substantial, with the 2008–09 Global Financial Crisis increasing the connectedness measures above their precrisis levels. The USA, China, and Korea are shown to be systemically important and to dominate APEC’s real activities, while outside the APEC region the roles of India and the UK are also non‐negligible. These results suggest that the majority of APEC economies are considerably open to output shocks from the dominant economies such that policymakers in APEC must be continuously conscious of headwinds originating from these sources.     

Back to literacy

One of the seminal works in the development of British cultural studies was Richard Hoggart's The Uses of Literacy , in which he presents a vision of working class communities in the 40 years since the First World War. To do this he drew particularly on his experiences of Hunslet in South Leeds. In this paper we revisit South Leeds 40 years on to examine continuities and changes in the community as evidenced through people's leisure and compare this with Hoggart's analysis. To do this we have drawn on census and other official statistics and our own observation and interviews in the field. In order to interpret today's communities in South Leeds we make use of theoretical developments in the interim. We suggest that in what Bauman (1997) refers to as ‘two nations society mark two’ people try to reinvent community and it is through leisure in particular that this is evidenced. We therefore conclude that any attempt to understand ‘community’ at the millennium must place leisure centre stage.     

卡耐基梅林大学商学院——防范IT风险泛滥

2007年,两名英国政府官员丢失了一张光盘,内容为2500万居民的个人及银行数据,而这些信息在黑市上价值25亿美元。2008年初,丹麦某数据中心出现了一个微小的失误,致使它的两个客户——某银行ATM网络瘫痪,全国范围内牛奶派送被迫暂停。同年9月,一个网络失误致使伦敦证券交易所全天停止交易活动,     

Do non-profit hospitals provide more charity care when faced with a mandatory minimum standard? Evidence from Texas

Policymakers often question whether not-for-profit (NFP) hospitals provide enough charity care to justify tax advantages. In 1993, Texas enacted legislation requiring NFP hospitals to provide certain community benefits at levels set forth in specific criteria to retain tax-exempt status; this paper focuses on the effect of the legislation’s requirement that NFP hospitals spend a minimum of 4% of net patient revenue on charity care. We also study a modification of the law passed in 1995, which allows the deduction of bad debts expense when calculating net patient revenue. This change effectively lowers required charity care spending, and our study considers whether Texas hospitals responded by reducing charity care spending.