The effect of vehicle structure characteristics on occupant restraint parameters. A parametric study. Technical report.

Mode of access: Internet.

Analytical modeling of driver response in crash avoidance maneuvering. Volume I: technical background. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Analytical modeling of driver response in crash avoidance maneuvering. Volume IV: user's guide for linear analysis, nonlinear simulation, part task simulation. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

An analysis of the automobile market: modeling of the long-run determinants of the demand for automobiles. Volume III: appendices to the Wharton E.F.A. Automobile Demand Model. Final report.

Transportation Department, Washington, D.C.

An analysis of the automobile market: modeling of the long-run determinants of the demand for automobiles. Volume II: simulation analysis using the Wharton E.F.A. Automobile Demand Model. Final report.

Transportation Department, Washington, D.C.

Diagnostic motor vehicle inspection demonstration projects, program engineering support. Volume 6 - appendix E: technical basis for cost benefit analyses. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

An analysis of the automobile market: modeling of the long-run determinants of the demand for automobiles. Volume I: the Wharton E.F.A. Automobile Demand Model. Final report.

Transportation Department, Washington, D.C.

Performance audit of the Department of Central Management Services' operation of the state vehicle fleet /

"House Resolution 658 directed the Office of the Auditor General (OAG) to audit the Department of Central Management Services' (CMS) operation of the fleet of passenger cars used by State executive agencies. The Resolution called for the audit to address the total number of cars; number of take-home cars; necessity of take-home vehicles; costs of vehicles in Fiscal Year 2009; and the adequacy of CMS' system to record their use and maintenance and to check for official use, including whether it is possible to implement a system to track vehicles for business only."

A new age of fuel performance code criteria studied through advanced atomistic simulation techniques

A fundamental step in understanding the effects of irradiation on metallic uranium and uranium dioxide ceramic fuels, or any material, must start with the nature of radiation damage on the atomic level. The atomic damage displacement results in a multitude of defects that influence the fuel performance. Nuclear reactions are coupled, in that changing one variable will alter others through feedback. In the field of fuel performance modeling, these difficulties are addressed through the use of empirical models rather than models based on first principles. Empirical models can be used as a predictive code through the careful manipulation of input variables for the limited circumstances that are closely tied to the data used to create the model. While empirical models are efficient and give acceptable results, these results are only applicable within the range of the existing data. This narrow window prevents modeling changes in operating conditions that would invalidate the model as the new operating conditions would not be within the calibration data set. This work is part of a larger effort to correct for this modeling deficiency. Uranium dioxide and metallic uranium fuels are analyzed through a kinetic Monte Carlo code (kMC) as part of an overall effort to generate a stochastic and predictive fuel code. The kMC investigations include sensitivity analysis of point defect concentrations, thermal gradients implemented through a temperature variation mesh-grid, and migration energy values. In this work, fission damage is primarily represented through defects on the oxygen anion sublattice. Results were also compared between the various models. Past studies of kMC point defect migration have not adequately addressed non-standard migration events such as clustering and dissociation of vacancies. As such, the General Utility Lattice Program (GULP) code was utilized to generate new migration energies so that additional non-migration events could be included into kMC code in the future for more comprehensive studies. Defect energies were calculated to generate barrier heights for single vacancy migration, clustering and dissociation of two vacancies, and vacancy migration while under the influence of both an additional oxygen and uranium vacancy.

On the significance of omitted variables in intersection crash modeling

Advances in safety research—trying to improve the collective understanding of motor vehicle crash causes and contributing factors—rest upon the pursuit of numerous lines of research inquiry. The research community has focused considerable attention on analytical methods development (negative binomial models, simultaneous equations, etc.), on better experimental designs (before-after studies, comparison sites, etc.), on improving exposure measures, and on model specification improvements (additive terms, non-linear relations, etc.). One might logically seek to know which lines of inquiry might provide the most significant improvements in understanding crash causation and/or prediction. It is the contention of this paper that the exclusion of important variables (causal or surrogate measures of causal variables) cause omitted variable bias in model estimation and is an important and neglected line of inquiry in safety research. In particular, spatially related variables are often difficult to collect and omitted from crash models—but offer significant opportunities to better understand contributing factors and/or causes of crashes. This study examines the role of important variables (other than Average Annual Daily Traffic (AADT)) that are generally omitted from intersection crash prediction models. In addition to the geometric and traffic regulatory information of intersection, the proposed model includes many spatial factors such as local influences of weather, sun glare, proximity to drinking establishments, and proximity to schools—representing a mix of potential environmental and human factors that are theoretically important, but rarely used. Results suggest that these variables in addition to AADT have significant explanatory power, and their exclusion leads to omitted variable bias. Provided is evidence that variable exclusion overstates the effect of minor road AADT by as much as 40% and major road AADT by 14%.

Performance of new-generation portable water-filled road safety barriers under vehicular impact

Portable water-filled barriers (PWFB) are roadside structures used to enhance safety at roadside work-zones. Ideally, a PWFB system is expected to protect persons and objects behind it and redirect the errant vehicle. The performance criteria of a road safety barrier system are (i) redirection of the vehicle after impact and (ii) lateral deflection within allowable limits. Since its inception, the PWFB has received criticism due to its underperformance compared to the heavier portable concrete barrier. A new generation composite high energy absorbing road safety barrier was recently developed by the authors.

Stability control of a railway vehicle using absolute stiffness and inerters

Work presented in this paper studies the potential of employing inerters -a novel mechanical device used successfully in racing cars- in active suspension configurations with the aim to enhance railway vehicle system performance. The particular element of research in this paper concerns railway wheelset lateral stability control. Controlled torques are applied to the wheelsets using the concept of absolute stiffness. The effects of a reduced set of arbitrary passive structures using springs, dampers and inerters integrated to the active solution are discussed. A multi-objective optimisation problem is defined for tuning the parameters of the proposed configurations. Finally, time domain simulations are assessed for the railway vehicle while negotiating a curved track. A simplification of the design problem for stability is attained with the integration of inerters to the active solutions. © 2012 IEEE.

Performance models of storage contention in cloud environments

We propose simple models to predict the performance degradation of disk requests due to storage device contention in consolidated virtualized environments. Model parameters can be deduced from measurements obtained inside Virtual Machines (VMs) from a system where a single VM accesses a remote storage server. The parameterized model can then be used to predict the effect of storage contention when multiple VMs are consolidated on the same server. We first propose a trace-driven approach that evaluates a queueing network with fair share scheduling using simulation. The model parameters consider Virtual Machine Monitor level disk access optimizations and rely on a calibration technique. We further present a measurement-based approach that allows a distinct characterization of read/write performance attributes. In particular, we define simple linear prediction models for I/O request mean response times, throughputs and read/write mixes, as well as a simulation model for predicting response time distributions. We found our models to be effective in predicting such quantities across a range of synthetic and emulated application workloads. 

Corporate Ownership, Control, and Firm Performance in Victorian Britain

Scholars have long debated whether ownership structure matters for firm performance. The standard view with respect to Victorian Britain is that family-controlled companies had a detrimental effect on operating profit and shareholder value. Here, we examine this view using a hand-collected corporate ownership dataset. Our main finding is that it was not necessarily the broad structure of corporate ownership that mattered for performance, but whether family blockholders had a governance role. Large active blockholders tended to increase operating performance, implying that they reduced managerial agency problems. In contrast, we find that directors who were independent of large family owners were more likely to increase shareholder value.

Long-term performance of mergers and acquisitions in ASEAN countries

The study looks at mergers and acquisitions (M&As) in ASEAN countries and examines the post-M&A performance using data from 2001 to 2012. The industry-adjusted operating performance tends to decline in the 3 years following an M&A. Yet, the results suggest that M&As completed during the financial crisis are more profitable than those implemented before and/or after the crisis. We argue that this is mainly due to the synergies created between the firms’ resources during the crisis which augur well for firms’ economic performance. We find that, during the crisis, certain characteristics of the firms like the relative size of the target, cross-border nature of deals, acquirer's cash reserves and friendly nature of deals are important determinants of long-term post-M&A operating performance. However, for M&As during the crisis, there appears to be no relationship between performance and firms’ characteristics linked to M&A activity such as payment method, industry relatedness and percentage of target's share acquired.