Momentum of Particles from Time-Of-Flight Measurements

In order to find the momentum of particles from time of flight measurements, I used a program called Geant4 to simulate experiments. I made a simple two detector setup, and I recreated a real world experiment. I spent a lot of time learning to code in C++ so I could use Geant4 correctly. I simulated these experiments shooting electrons, muons, and pions through the geometry and measured the time at two points in their flight. Subtracting the second time from the first gave me the time of flight distribution for each particle. I used ROOT to draw histograms of the time of flight for each experiment and calculate the mean values. From the time of flight I found the momentum, knowing the mass and path length of each particle. I calculated the ideal times for each experiment from the fixed particle momentum at which I fired. I then compared these calculated times to the experimental times to see the relationship between the particles. This led me to theorize why the pions and muons were so much slower than electrons, and why heavier particles have more energy loss from ionization. I also used my data from the recreation of the real world muon scattering experiment to predict initial momentums of particles based on the measured time of flight

A causal modelling framework for reference-based imputation and tipping point analysis in clinical trials with quantitative outcome

We consider estimation in a randomised placebo-controlled or standard-of-care-controlled drug trial with quantitative outcome, where participants who discontinue an investigational treatment are not followed up thereafter, and the estimand follows a treatment policy strategy for handling treatment discontinuation. Our approach is also useful in situations where participants take rescue medication or a subsequent line of therapy and the estimand follows a hypothetical strategy to estimate the effect of initially randomised treatment in the absence of rescue or other active treatment. Carpenter et al proposed reference-based imputation methods which use a reference arm to inform the distribution of post-discontinuation outcomes and hence to inform an imputation model. However, the reference-based imputation methods were not formally justified. We present a causal model which makes an explicit assumption in a potential outcomes framework about the maintained causal effect of treatment after discontinuation. We use mathematical argument and a simulation study to show that the "jump to reference", "copy reference" and "copy increments in reference" reference-based imputation methods, with the control arm as the reference arm, are special cases of the causal model with specific assumptions about the causal treatment effect. We also show that the causal model provides a flexible and transparent framework for a tipping point sensitivity analysis in which we vary the assumptions made about the causal effect of discontinued treatment. We illustrate the approach with data from two longitudinal clinical trials

Automating Vendor Fraud Detection in Enterprise Systems

Fraud is a multi-billion dollar industry that continues to grow annually. Many organisations are poorly prepared to prevent and detect fraud. Fraud detection strategies are intended to quickly and efficiently identify fraudulent activities that circumvent preventative measures. In this paper we adopt a Design-Science methodological framework to develop a model for detection of vendor fraud based on analysis of patterns or signatures identified in enterprise system audit trails. The concept is demonstrated be developing prototype software. Verification of the prototype is achieved by performing a series of experiments. Validation is achieved by independent reviews from auditing practitioners. Key findings of this study are: i) automating routine data analytics improves auditor productivity and reduces time taken to identify potential fraud, and ii) visualisations assist in promptly identifying potentially fraudulent user activities. The study makes the following contributions: i) a model for proactive fraud detection, ii) methods for visualising user activities in transaction data, iii) a stand-alone MCL-based prototype.</p

Automating Vendor Fraud Detection in Enterprise Systems

Fraud is a multi-billion dollar industry that continues to grow annually. Many organizations are poorly prepared to prevent and detect fraud. Fraud detection strategies are intended to quickly and efficiently identify fraudulent activities that circumvent preventative measures. In this paper, we adopt a DesignScience methodological framework to develop a model for detection of vendor fraud based on analysis of patterns or signatures identified in enterprise system audit trails. The concept is demonstrated by developing prototype software. Verification of the prototype is achieved by performing a series of experiments. Validation is achieved by independent reviews from auditing practitioners. Key findings of this study are: (a) automating routine data analytics improves auditor productivity and reduces time taken to identify potential fraud; and (b) visualizations assist in promptly identifying potentially fraudulent user activities. The study makes the following contributions: (a) a model for proactive fraud detection; (b) methods for visualizing user activities in transaction data; and (c) a stand-alone Monitoring and Control Layer (MCL) based prototype

Impact Of Stock Options On Quarterly EPS: A Proposal For Change

The purpose of this paper is to: 1) explore the annual and quarterly economic impact of FAS 123 on a group of S&amp;P 100 firms; 2) propose changes in the measurement and disclosure rules of FAS 123; and 3) determine the annual and quarterly economic impact of these proposed changes on the same group of S&amp;P 100 firms. While both FAS 123 and dynamic option expense measurement approaches have material economic impact and reduce the EPS amounts reported under APBO 25 rules approximately 16 percent or more, no statistically significant differences are found between the results of these two approaches in any year 2000 quarters. However, when the sample is split into two groups based on negative and positive quarterly returns, the differences between the results of the two methods are statistically significant for seven of eight quarterly observations. Compared to the static (FAS 123) measurement approach, the dynamic (quarterly recalculated) approach results in lower option expenses and higher EPS values for firms with declining stock prices and higher option expenses and lower EPS values for firms with increasing stock prices. Thus, the dynamic measurement approach proposed in this paper more faithfully represents the economic reality of individual firms

VIS³COS. III. Environmental effects on the star formation histories of galaxies at z ∼ 0.8 seen in [O II], Hδ, and D_n4000

We present spectroscopic observations of 466 galaxies in and around a superstructure at z ∼ 0.84 targeted by the VIMOS Spectroscopic Survey of a Supercluster in the COSMOS field (VIS³COS). We use [OII]λ3727, Hδ, and D_n4000 to trace recent, medium-, and long-term star formation histories and investigate the effect of stellar mass and local environment on them. By studying trends in individual and composite galaxy spectra, we find that stellar mass and environment play a role in the observed galactic properties. Galaxies with low stellar mass (10  11) shows an increase in Hδ absorption strengths in intermediate-density environments (e.g. filaments). Galaxies with intermediate stellar mass (10.5 <  log₁₀ (M⋆/M⊙) < 11) have similar Hδ absorption profiles in all environments, but show an indication of enhanced [OII] emission in intermediate-density environments. This indicates that field galaxies with low stellar mass and filament galaxies with high stellar mass are more likely to have experienced a recent burst of star formation, while galaxies of the intermediate stellar-mass show an increase of star formation at filament-like densities. We also find that the median [OII] equivalent width (|EW_([OII])|) decreases from 27 ± 2 Å to 2.0^(+0.5)_(−0.4) Å and D_n4000 increases from 1.09 ± 0.01 to 1.56 ± 0.03 with increasing stellar mass (from ∼10^(9.25) to ∼10^(11.35) M⊙). For the dependence on the environment, we find that at fixed stellar mass, |EW_([OII])| is tentatively lower in environments with higher density. We find for D_n4000 that the increase with stellar mass is sharper in denser environments, which indicates that these environments may accelerate galaxy evolution. Moreover, we find higher D_n4000 values in denser environments at fixed stellar mass, suggesting that galaxies are on average older and/or more metal rich in these dense environments. This set of tracers depicts a scenario where the most massive galaxies have, on average, the lowest specific star formation rates and the oldest stellar populations (age ≳ 1 Gyr, showing a mass-downsizing effect). We also hypothesize that the observed increase in star formation (higher EW_([OII]|), higher specific star formation rate) at intermediate densities may lead to quenching because we find that the quenched fraction increases sharply from the filament to cluster-like regions at similar stellar masses

Art operating procedures and transformative kinetics: the altercation and energy of art

My body of work and thesis essay investigates the role of the human body and the physical and psychological way it informs meaning on artistic processes. My longstanding interest in kinesiology, sports psychology, and the physical training of the human body are the corner stone of my creative practice. I investigate how to manipulate the body, adopting the model of an athlete in training for improving my physical skills as an artist. And finally, I test the possibility of using the body’s reaction to and interaction with materials to reach a creative goal. Challenges I set for myself during art making resemble intentional challenges of an athlete. Makes the opposition to the artist’s body, the foremost visual evidence, through which viewers associate their own personal triumphs and struggles. I assert that documenting the art making process, especially the experience of developing and mastering skills and concepts, can potentially have meaning for both the artist and the viewer

The Market Reaction To Voluntary Stock Option Expense Recognition Announcements

Recently, numerous firms announced that they would voluntarily begin recognizing the SFAS 123 expense. We use standard event-study methodology and regression analysis to analyze the equity valuation effects of these announcements. SFAS 123 requires firms to calculate the fair value of stock options granted but allows firms to either recognize the expense in their income statements or simply disclose the impact on net income in financial statement footnotes. Our results reveal statistically significant positive abnormal announcement period returns for the full sample of firms analyzed, with results mainly driven by firms that are early (July or August 2002 announcements) announcers. In addition, regressions confirm a significant negative relationship between the size of the stock option expense and the abnormal announcement returns

Dimensionen politischer Konflikte: die Analyse von namentlichen Abstimmungen in Parlamenten mit dem Verfahren der Mokken-Skalierung

In dem Aufsatz stellen die Autoren ein probalistisches Skalierungsmodell ("Mokken-Skalierung") vor, mit dem sie das Abstimmungsverhalten der Abgeordneten und daran anknüpfend die Konfliktstrukturen der Frankfurter Nationalversammlung und der französischen Assemble Nationale Constituante analysieren. Im Zentrum der methodologischen Überlegungen steht dabei die oft schwierige "Übersetzung" von theoretischen Begriffen (wie Industrialisierung, legitime Herrschaft, Klassenbewußtsein) in empirische Indikatoren. Bestimmte Aspekte dieser in der Forschungspraxis oft nur intuitiv geleisteten Zuordnung werden durch die verschiedenen Skalierungsverfahren objektivierbar. Dabei haben sich - wie auch in der Kausalanalyse - deterministische Modelle (wie die Guttmann-Skalierung), die "Fehler" in den Beobachtungsgrößen oder Variablenbeziehungen nicht explizit berücksichtigen, in vielen Anwendungssituationen als zu restriktiv erwiesen. (pmb