Control charts for health care monitoring: the heterogeneous case

Attribute data from high quality processes can be monitored adequately by using negative binomial charts. The optimal choice for the number r of failures involved depends on the expected rate of change in failure rate during Out-of-Control. To begin with, such results have been obtained for the case of homogeneous data. But especially in health care monitoring, (groups of) patients will often show large heterogeneity. In the present paper we will present an overview of how this problem can be dealt with. Two situations occur: the underlying structure is either unknown (the overdispersion case) or known (risk adjustment feasible). An additional complication to be dealt with is the fact that in practice typically all parameters involved are unknown. Hence estimated versions of the new proposals need to be discussed as well

The heavenly liquidity twin : the increasing importance of liquidity risk

Liquidity and solvency have been called the"heavenly twins"of banking (Goodhart, Charles,'Liquidity Risk Management', Financial Stability Review -- Special Issue on Liquidity, Banque de France, No. 11, February, 2008). Since these"twins"interact in complex ways, it is difficult -- particularly at times of crisis--to distinguish between them, especially in the presence of information asymmetries (Information asymmetry occurs when one party has more or better information than the other, creating an imbalance of power, giving rise to adverse selection and moral hazard ). An insolvent bank can be liquid or illiquid, and a solvent bank may be at times illiquid. In the latter case, insolvency is not far away, since banking is grounded in information and confidence, and it is confidence which in the end determines liquidity. In other words, liquidity is very much endogenous, determined by the general condition of a bank, as well as the perception of it by the public and market participants. Dealing with liquidity risk is more challenging than dealing with other risks, since liquidity is the result of all the operations of a bank and it is fundamentally a relative concept which compares segments of the balance sheet on the asset and liability sides. It does not deal with absolutes, like arguably the concept of capital and it explains why there is not an internationally recognized"Liquidity Accord". This Working Paper addresses key concepts like market and funding liquidity and basic tools to address liquidity issues like cash flows, liquidity gaps and some selected financial ratios. It aims at providing an introductory guide to risk assessment and management, and provides useful and practical guidelines to undertake liquidity assessments which could prove useful in preparing Financial Assessment Programs (FSAPS) in member countries of the Bretton Woods institutions.Debt Markets,Banks&Banking Reform,Currencies and Exchange Rates,Emerging Markets,Bankruptcy and Resolution of Financial Distress

Humans do not always act selfishly: social identity and helping in emergency evacuation simulation

To monitor and predict the behaviour of a crowd, it is imperative that the technology used is based on an accurate understanding of crowd psychology. However, most simulations of evacuation scenarios rely on outdated assumptions about the way people behave or only consider the locomotion of pedestrian movement. We present a social model for pedestrian simulation based on self-categorisation processes during an emergency evacuation. We demonstrate the impact of this new model on the behaviour of pedestrians and on evacuation times. In addition to the Optimal Steps Model for locomotion, we add a realistic social model of collective behaviour

Angular Control Charts: A New Perspective for Monitoring Reliability of Multi-State Systems

Control charts, as had been used traditionally for quality monitoring, were applied alternatively to monitor systems' reliability. In other words, they can be applied to detect changes in the failure behavior of systems. Such purpose imposed modifying traditional control charts in addition to developing charts that are more compatible with reliability monitoring. The latter developed category is known as probability limits control charts. The existing reliability monitoring control charts were only dedicated to binary-state systems, and they can't be used to monitor several states simultaneously. Therefore, this paper develops a design of control charts that accommodates multi-state systems, called here as the Angular Control Chart, which represents a new version of the probability limits control charts. This design is able to monitor state transitions simultaneously and individually in addition. Illustrative system examples are implemented to explore the monitoring procedure of the new design and to demonstrate its efficiency, effectiveness, and limitations.Comment: 18 pages; 13 figure

External financing of US corporations: Are loans and securities complements or substitutes?

“Multiple avenues of intermediation” (Greenspan 2000) suggest substitutability of corporate loan and bond finance which smooths external financing flows. Holmstrom and Tirole (1997) stress complementarity; for most firms bank finance and consequent monitoring is essential for bond finance. Econometric work based on their model is consistent with complementarity both on average over time and during financial crises, and for levels and volatilities. It implies that “multiple avenues” may not be effective as a buffer in a bank credit crunch, and hence supply-side blockages of bank credit may impact on real activity. There are important implications for regulation, not least Basel II

Interactive Chemical Reactivity Exploration

Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force-feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the Samson programming environment.Comment: 36 pages, 14 figure