Augmented Weighted Estimators Dealing with Practical Positivity Violation to Causal inferences in a Random Coefficient Model.

The inverse probability of treatment weighted (IPTW) estimator can be used to make causal inferences under two assumptions: (1) no unobserved confounders (ignorability) and (2) positive probability of treatment and of control at every level of the confounders (positivity), but is vulnerable to bias if by chance, the proportion of the sample assigned to treatment, or proportion of control, is zero at certain levels of the confounders. We propose to deal with this sampling zero problem, also known as practical violation of the positivity assumption, in a setting where the observed confounder is cluster identity, i.e., treatment assignment is ignorable within clusters. Specifically, based on a random coefficient model assumed for the potential outcome, we augment the IPTW estimating function with the estimated potential outcomes of treatment (or of control) for clusters that have no observation of treatment (or control). If the cluster-specific potential outcomes are estimated correctly, the augmented estimating function can be shown to converge in expectation to zero and therefore yield consistent causal estimates. The proposed method can be implemented in the existing software, and it performs well in simulated data as well as with real-world data from a teacher preparation evaluation study

Kept Things

The things that occupy our lives tell human stories. They often go beyond literal interpretation, leaving space for places, people, desires, dreams, and ideologies to be signified and examined. Personal history is a well-traveled source of inspiration, and it provides significant, meaningful symbols for the concepts I’m engaging with in my newest collection. My project, titled Kept Things, is a collection of three nonfiction pieces examining why and how things are kept, lost, and discarded, whether we have a choice in the matter or not. The significance of symbols to identity and memory acts as a through-line between each piece. The first of these pieces, “Opportunity”, examines the ties to and experience of losing an ancestral house in Opportunity, Montana. Feelings of family instability and grief are central to the piece, and circle back around in the following pieces, the next of which is “Keeper”. “Keeper” is a scene-based character and relationship study of my brother and I. I use his struggles with addiction as a focal point within the piece. The reader is given context to decide for themselves whether all relationships should be preserved and fostered, or if it is a better decision to let people go, even those closest to us. The final piece of this collection is “In the House of the Lord”, which takes the metaphysical object of an interpersonal relationship and stretches it to a personal relationship with an entire faith system, mine being Catholicism. In delving back into religious experience (Catholic and otherwise) I seek to determine the real applicability of shaping our identity markers to our own design, and how we can shape ourselves through conscious manipulation of what we let affect our thinking and self-worth. These three pieces will work together to illustrate different manifestations of “kept things” and what that phrase can mean to every individual

Pedestrian safety at signalized intersections operating the flashing yellow arrow

At signalized intersections, pedestrians are considered to be amongst the most vulnerable. When in the crosswalk at intersections without protected left-turn phasing, pedestrians are particularly at risk from left-turning vehicles. Until recently, a wide variety of indications were in use across the US to indicate a permissive left-turn condition to the driver. In Oregon, the Flashing Yellow Arrow (FYA) has been used to indicate the permissive left-turn condition for approximately 10 years. With the addition of the FYA in the 2009 MUTCD, it is likely that its use will continue to increase nationally. Though many operational and safety issues have been studied about the FYA indication, this research proposes to fully investigate factors that influence driver behavior in the context of the permissive left-turn conflict with pedestrians. Specifically, the research seeks to study driver glance behavior to identify reasons why drivers are, "looking at but not seeing" pedestrians in or near the crosswalk or not searching for the presence of pedestrians at all

Permissive Left-Turn Behavior at the Flashing Yellow Arrow in the Presence of Pedestrians

Use of the flashing yellow arrow indication for permissive left-turn control has become more common in the U.S. since it was adopted in the 2009 Edition of the Manual on Uniform Traffic Control Devices. A complete understanding of the safety implications at signalized intersections is critically important. This paper examines the results of a permissive left-turn driver behavior study conducted in a high fidelity driving simulator. The experimental results suggest 1) that when there are more pedestrians present in the conflicting crosswalk, the driver’s average fixation duration on crossing pedestrians is greater than when there is minimal pedestrian activity; 2) that 4% to 7% of drivers do not fixate on pedestrians in the crosswalk when completing their left turn; and 3) that 39% of drivers do not fixate on likely pedestrian locations when pedestrians are not present

Thermal Spray Formation of Polymer Coatings

This innovation forms a sprayable polymer film using powdered precursor materials and an in-process heating method. This device directly applies a powdered polymer onto a substrate to form an adherent, mechanically-sound, and thickness-regulated film. The process can be used to lay down both fully dense and porous, e.g., foam, coatings. This system is field-deployable and includes power distribution, heater controls, polymer constituent material bins, flow controls, material transportation functions, and a thermal spray apparatus. The only thing required for operation in the field is a power source. Because this method does not require solvents, it does not release the toxic, volatile organic compounds of previous methods. Also, the sprayed polymer material is not degraded because this method does not use hot combustion gas or hot plasma gas. This keeps the polymer from becoming rough, porous, or poorly bonded

Acoustic Source Localization in Aircraft Interiors Using Microphone Array Technologies

Using three microphone array configurations at two aircraft body stations on a Boeing 777-300ER flight test, the acoustic radiation characteristics of the sidewall and outboard floor system are investigated by experimental measurement. Analysis of the experimental data is performed using sound intensity calculations for closely spaced microphones, PATCH Inverse Boundary Element Nearfield Acoustic Holography, and Spherical Nearfield Acoustic Holography. Each method is compared assessing strengths and weaknesses, evaluating source identification capability for both broadband and narrowband sources, evaluating sources during transient and steady-state conditions, and quantifying field reconstruction continuity using multiple array positions

Predicted Causality in Decision Making: The Role of Culture

In the wider sense, decision making is embedded in the problem-solving process and its many stages (Davidson and Sternberg, 2003; Güss et al., 2010). In the narrow sense, decision making is understood as the ability to select one of several alternatives and to act accordingly (Güss 2004). Previous research has often focused on decision making in relatively predictable environments with clear goals (e.g., expected utility theory of von Neumann and Morgenstern, 1944). In recent decades the focus has been on decision making heuristics, i.e., strategies or rules of thumb, applied in uncertain situations (e.g., Tversky and Kahneman, 1974; Simon, 1979; Gigerenzer and Gaissmaier, 2011). Causality plays an important role in many cognitive processes – and causal cognition is itself influenced by culture (e.g., Norenzayan and Nisbett, 2000; Medin and Atran, 2004; Beller et al., 2009; Bender and Beller, 2011; for a controversial discussion of causal cognition, see Sperber et al., 1995). Causality is especially important during the decision-making process, because the decision maker has to predict what consequences specific decisions bring about before making a decision

Ein Beitrag zur Anreicherung und Bestimmung kleinster Formaldehydmengen in Reinstluft

SIGLEAvailable from the library of Mainz Univ. (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman