Bayesian Analysis of Hazard Regression Models under Order Restrictions on Covariate Effects and Ageing

We propose Bayesian inference in hazard regression models where the baseline hazard is unknown, covariate effects are possibly age-varying (non-proportional), and there is multiplicative frailty with arbitrary distribution. Our framework incorporates a wide variety of order restrictions on covariate dependence and duration dependence (ageing). We propose estimation and evaluation of age-varying covariate effects when covariate dependence is monotone rather than proportional. In particular, we consider situations where the lifetime conditional on a higher value of the covariate ages faster or slower than that conditional on a lower value; this kind of situation is common in applications. In addition, there may be restrictions on the nature of ageing. For example, relevant theory may suggest that the baseline hazard function decreases with age. The proposed framework enables evaluation of order restrictions in the nature of both covariate and duration dependence as well as estimation of hazard regression models under such restrictions. The usefulness of the proposed Bayesian model and inference methods are illustrated with an application to corporate bankruptcies in the UK

Development of a radar simulator for monitoring wake vortices in rainy weather

A simulator for the evaluation of the radar signature of raindrops within wake vortices is presented. Simulated Doppler spectrum of raindrops within vortices let to think that it could be a potential criterion for identifying wake vortex hazard in rainy weather

A pilot rating scale for vortex hazard evaluation

A pilot rating scale is developed for subjective assessment of hazard resulting from wake vortex encounter upsets. The development of the rating scale is based on a survey of 48 pilots regarding the semantic properties of various phrases and a choice of formats for the rating scale. The rating scale can be used to define a hazard/nonhazard boundary as well as to determine a measure of the hazard

Preliminary hazards summary for Nerva irradiation testing at Plum Brook Reactor Facility

Safety hazard evaluation for irradiation testing in simulated NERVA environment at cryogenic temperature

Team Incentives and Reference-Dependent Preferences

This paper examines a multi-agent moral hazard model in which agents have expectation-based reference-dependent preferences `a la K˝oszegi and Rabin (2006, 2007). The agents’ utilities depend not only on their realized outcomes but also on the comparisons of their realized outcomes with their reference outcomes. Due to loss aversion, the agents have a first-order aversion to wage uncertainty. Thus, reducing their expected losses by partially compensating for their failure may be beneficial for the principal. When the agent is loss averse and the project is hard to achieve, the optimal contract is based on team incentives which exhibit either joint performance evaluation or relative performance evaluation. Our results provide a new insight: team incentives serve as a loss-sharing device among agents. This model can explain the empirical puzzle of why firms often pay a bonus to low-performance employees as well as high-performance employees.Moral Hazard, Team Incentives, Reference-Dependent Preferences, Loss Aversion, Joint Performance, Evaluation, Relative Performance Evaluation

Non-constant Hazard Function and Inflation Dynamics

This paper explores implications of nominal rigidity characterized by a non-constant hazard function for aggregate dynamics. I derive the NKPC under an arbitrary hazard function and parameterize it with the Weibull duration model. The resulting Phillips curve involves lagged inflation and lagged expectations. It nests the Calvo NKPC as a limiting case in the sense that the effects of both terms are canceled out under the constant-hazard assumption. Furthermore, I find lagged inflation always has negative coefficients, thereby making it impossible to interpret inflation persistence as intrinsic. The numerical evaluation shows that the increasing hazard function leads to hump-shaped impulse responses of ination to monetary shocks, and output leads inflation.Hazard function, Weibull distribution, New Keynesian Phillips Curve

Time-dependent pricing and New Keynesian Phillips curve

This paper explores what can be lost when assuming price adjustment is a time - independent (memoryless) process.I derive a generalized NKPC in an optinizing model with the non- constant hazard function and trend inflation. Memory emerges in the resulting Phillips curve through the presence of lagged inflation and lagged expectations. It nests the Calvo NKPC as a limitting case in the sense that the effect of both terms are canceled out by one another under the constant-hazard assumption. Furthermore, I find lagged inflation always has negative coefficients, thereby making it impossible to interpret inflation persistence as intrinsic to the model. The numerical evaluation shows that introducing trend inflation strengthens the effects of the increasing hazard function on the inflation dynamics . The model can jointly account for persistent dynamics of inflation and output, hump-shaped impulse responses of inflation to monetary shocks, and the fact that high trend inflation leads to more persistence in inflation but not for real variables. --Intrinsic inflation persistance,Hazard function,New Keynesian Phillips Curve

"Role of Relative and Absolute Performance Evaluations in Intergroup Competition"

We investigate the moral hazard problem in which a principal delegates multiple tasks to multiple workers. The principal imperfectly monitors their action choices by observing the public signals that are correlated with each other through a macro shock. He divides the workers into two groups and makes them compete with each other. We show that when the number of tasks is sufficiently large, relative performance evaluation between the groups accompanied with absolute performance evaluation results in eliminating unwanted equilibria. In this case, any approximate Nash equilibrium nearly induces the first-best allocation.

Evaluation of a sudden brake warning system: Effect on the response time of the following driver

This study used a video-based braking simulation dual task to carry out a preliminary evaluation of the effect of a sudden brake warning system (SBWS) in a leading passenger vehicle on the response time of the following driver. The primary task required the participants (N = 25, 16 females, full NZ license holders) to respond to sudden braking manoeuvres of a lead vehicle during day and night driving, wet and dry conditions and in rural and urban traffic, while concurrently performing a secondary tracking task using a computer mouse. The SBWS in the lead vehicle consisted of g-force controlled activation of the rear hazard lights (the rear indicators flashed), in addition to the standard brake lights. Overall, the results revealed that responses to the braking manoeuvres of the leading vehicles when the hazard lights were activated by the warning system were 0.34 s (19%) faster compared to the standard brake lights. The SBWS was particularly effective when the simulated braking scenario of the leading vehicle did not require an immediate and abrupt braking response. Given this, the SBWS may also be beneficial for allowing smoother deceleration, thus reducing fuel consumption. These preliminary findings justify a larger, more ecologically valid laboratory evaluation which may lead to a naturalistic study in order to test this new technology in ‘real world’ braking situations

Role of Relative and Absolute Performance Evaluations in Intergroup Competition

We investigate the moral hazard problem in which a principal delegates multiple tasks to multiple workers. The principal imperfectly monitors their action choices by observing the public signals that are correlated with each other through a macro shock. He divides the workers into two groups and makes them compete with each other. We show that when the number of tasks is sufficiently large, relative performance evaluation between the groups accompanied with absolute performance evaluation results in eliminating unwanted equilibria. In this case, any approximate Nash equilibrium nearly induces the first-best allocation.