Testing for idiosyncratic Treatment Effect Heterogeneity

This paper provides asymptotically valid tests for the null hypothesis of no treatment effect heterogeneity. Importantly, I consider the presence of heterogeneity that is not explained by observed characteristics, or so-called idiosyncratic heterogeneity. When examining this heterogeneity, common statistical tests encounter a nuisance parameter problem in the average treatment effect which renders the asymptotic distribution of the test statistic dependent on that parameter. I propose an asymptotically valid test that circumvents the estimation of that parameter using the empirical characteristic function. A simulation study illustrates not only the test's validity but its higher power in rejecting a false null as compared to current tests. Furthermore, I show the method's usefulness through its application to a microfinance experiment in Bosnia and Herzegovina. In this experiment and for outcomes related to loan take-up and self-employment, the tests suggest that treatment effect heterogeneity does not seem to be completely accounted for by baseline characteristics. For those outcomes, researchers could potentially try to collect more baseline characteristics to inspect the remaining treatment effect heterogeneity, and potentially, improve treatment targeting.Comment: 50 pages (31 pages main text), 6 tables (5 main tables and 1 table in the appendix

Feasibility Study of Miniature LWIR Cameras in Quantitative Thermal Measurements

Thermal imaging in scientific applications has traditionally involved large and expensive cameras with static mounting. Applications of thermal imaging include: gas detection, heat sensing, stress analysis of materials, as well as many other research applications. This research studies the feasibility of replacing large thermal cameras with the FLIR Lepton, a miniature thermal sensor with a resolution of 60x80 pixels, to be used for quantitative scientific measurements. The benefits of using this camera include the small package size, as well as a cost of ten times less than traditional thermal cameras. Software was created to convert the qualitative image into quantitative data. Several cameras were embedded into one imaging system to demonstrate the potential of integrating multiple sensors to collect more data about the object being tested. Further work will be done to verify that the sensors produce accurate quantitative data by comparing the FLIR Lepton measurements with the measurements from a higher resolution thermal camera

Feasibility Study for the Application of Open Source UAS Autopilot Simulator

Constant development in Unmanned Aircraft System (UAS) technologies results in evolving aircraft, instrumentation, and control programs of these systems. An open source simulator was examined as a potential method of testing UAS platforms changes. The open source simulator was used to simulate flights flown by an actual platform. Existing flight data was used as a base line of comparison for the telemetry data of the simulated flight. Patterns in parameters such as vehicle attitude and throttle output were compared between the simulated and actual results to determine if the simulator produced an accurate representation of a physical flight. Analysis of the simulated vehicle exhibited similar behavior to that of the actual vehicle in most of the flight data collected. Simplification in the flight simulator model may be responsible for the deviations in magnitude observed between the two sets of data. Three points of interest in each of the three test cases were chosen as checks for the values in the data. These points in the flight were studied in the various graphs of the parameters graphed and the difference between the simulated and actual values was calculated. The values at these points stayed within an average of 0° and 30° for vehicle attitude and between 0% and 33.3% throttle difference over the three test cases. The average difference in attitude was 5.1° over 93 compared values and 8.1% in throttle over 18 compared values. On average the simulator showed good agreement to existing flight data and therefore will be a good tool to simulate flights prior to a mission. The accuracy of the results may be improved with further development of the simulation model

Fuel Optimal Maneuvers for Multispacecraft Interferometric Imaging Systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76545/1/AIAA-20178-139.pd

At What Level Should One Cluster Standard Errors in Paired Experiments, and in Stratified Experiments with Small Strata?

In paired experiments, units are matched into pairs, and one unit of each pair is randomly assigned to treatment. To estimate the treatment effect, researchers often regress their outcome on a treatment indicator and pair fixed effects, clustering standard errors at the unit-of-randomization level. We show that the variance estimator in this regression may be severely downward biased: under constant treatment effect, its expectation equals 1/2 of the true variance. Instead, we show that researchers should cluster their standard errors at the pair level. Using simulations, we show that those results extend to stratified experiments with few units per strata.Comment: fifth version, 49 pages, 5 tables, (main paper until page 21, then supplement