USAF Academy Research Articles

Benefits of completing homework for students with different aptitudes in an introductory electricity and magnetism course

Department of Physics, United States Air Force Academy,USAF Academy, Colorado 80840, USA(Received 27 May 2014; revised manuscript received 29 October 2014; published 17 February 2015)We examine how student aptitudes impact how much students learn from doing graded online andwritten homework in an introductory electricity and magnetism course. Our analysis examines thecorrelation between successful homework completion rates and exam performance as well as howchanges in homework completion correlate with changes in exam scores for students with differentphysics aptitudes. On average, successfully completing many homework problems correlated tobetter exam scores only for students with high physics aptitude. On the other hand, all other studentsshowed zero or even a negative correlation between successful homework completion and examperformance. Low- and medium-aptitude students who did more homework did no better andsometimes scored lower on exams than their low- and medium-aptitude peers who did lesshomework. Our work also shows that long-term changes in homework completion correlated tolong-term changes in exam scores only for students with high physics aptitude, but not for studentswith medium or low aptitude. We offer several explanations for the disparity in homework learninggains, including cognitive load theory, ineffective homework strategies, and various mismatchesbetween homework and exams. Several solutions are proposed to address these possible deficienciesin graded online and written homework.

I Hated Electromagnetics [Ethically Speaking

The author discusses his experience as a senior Electrical Engineering undergraduate student at the USAF Academy taking his first course in electromagnetics.

The Interpreter (review)

Reviewed by: The Interpreter Alan M. Osur The Interpreter. By Alice Kaplan . Chicago, Ill.: University of Chicago Press, 2007. ISBN 0-226-42425-1. Photographs. Notes. Index. Pp. xii, 240. $15.00. One would not expect a book heavily based on a novel to be a credible historical work, but in The Interpreter Alice Kaplan does a remarkable job of documenting a difficult and troubling period in the history of race relations in the US Army. She accomplishes this feat because of her thorough research involving military records and other primary source material, oral interviews, and her ability to grasp the workings of the army in France during the period 1944-1946. Kaplan's book tells the story of Louis Guilloux, a French writer who for a short period in 1944 worked for the US Army as a translator. Guilloux was himself the author of OK, Joe, published in France in 1976 after 12 years of work. Guilloux translated for a capital case involving an African American soldier who was found guilty and executed. Looking at the case through the eyes of the soldier, lawyers, and Guilloux, Kaplan is able to show that the evidence [End Page 272] against the soldier was weak and that the execution was not justified. Guilloux was involved with another case involving a white officer, a combat hero also accused of murder. Here the evidence against him was strong, but better legal counsel led to an acquittal. Kaplan believes that race was a determining factor, and she illustrates how much the issue of race entered into the picture. The fact that the white officer's record was outstanding and that his lawyer was more experienced and skillful than the one defending the African American weakens her comparison somewhat, but her position is strong nonetheless. In an ironic twist of fate, the excellent prosecutor in the case involving the African American became the excellent defense attorney for the white officer. Along with the discussions of these two cases comes a fascinating analysis of soldiers, lawyers, commanders, and racial conditions in the Brittany area of France after the Normandy invasion, much of which is described in Guilloux's book. For example, African Americans had to deal with the negative impact of racism and segregation, both in their state-side training camps and in the operational theater. One indicator of the conditions Kaplan documents is the racial disparity in the sentencing of whites and blacks in Europe, especially for capital crimes. As would be expected from a professor of Literature and History at Duke University, Kaplan researches and writes well in creating a powerful book; it is gripping because of the subject matter and her handling of it. Her references consist of valuable trial records and oral histories from descendants, relatives, and friends of all parties involved. As much as possible, she provides an analysis of the individual personalities, including those charged, court officials, lawyers, witnesses, and commanders. Throughout the book, we get a sense of knowing real human beings dealing with genuine issues. Alice Kaplan successfully demonstrates that during this period racial conditions, trial location, and lawyer selection were important in determining the resolution of trials of service troops in the US Army. Alan M. Osur USAF Academy Colorado Springs, Colorado Copyright © 2007 Society for Military History

Fire-Fighting Mobile Robotics and Interdisciplinary Design-Comparative Perspectives

The objective of this paper is to illustrate the benefits of an autonomous fire-fighting robot design competition as an effective tool for undergraduate education. It presents experiences at the United States Air Force Academy, USAF Academy, CO; Pennsylvania State University-Abington; and Trinity College, Hartford, CT, together with the results of the contest surveys conducted in collaboration with The Technion*Israel Institute of Technology, Haifa. The primary goal of the design project is to create an autonomous mobile robot that navigates through a maze searching for a fire (simulated by a burning candle), detects the candle's flame, extinguishes the flame, and returns to a designated starting location in the maze. The fire-fighting design contest promotes interdisciplinary design and teamwork. To accomplish the stated goal, students must integrate knowledge gained from such classes as engineering design, circuits, controls, signals and systems, computer programming, mathematics, and engineering mechanics. Within the three institutions, the contest has been successfully utilized as a foundation for a wide range of educational goals. These activities include freshman design, robotics courses, K-12 outreach, senior design projects, and undergraduate research.

A laser induced diagnostic technique for velocity measurements using liquid crystal thermography

Wind tunnel experiments were performed to show that wind velocity could be correlated to thermal patterns generated on a model surface. The idea makes use of the thermal patterns generated by a laser thermal tuft that was originally developed and patented (Patent #5,963,292) by researchers at the USAF Academy and the University of California, Davis. The present study quantifies this flow visualization idea by correlating the length of the thermal tuft to velocity and demonstrates that this measurement is strongly dependent on laser power. Until now, the laser thermal tuft has been used only to qualitatively characterize flow fields. By quantifying flow velocity, this extension of the patented idea may promote increased usage of this laser thermal tuft technique.

The case for Ada at the USAF academy

This paper describes our experience with selecting Ada as the primary programming language for Computer Science and Computer Engineering majors at the USAF Academy. We have decided to teach Ada in the first three courses of these majors for the next few years. Our criteria for selecting Ada are based on features of the language (such as strong typing, lack of single-character errors, and case insensitivity), features of the compiler, (such as error messages and warnings), and features of the overall development experience (such as development environments, availability of textbooks, GUI development support, and industry acceptance). We compared Ada with Java, C++, and C#.

Strength evolution in PM compacts as a function of sintering time and temperature: G.A.Soales. (USAF Academy, USA.)

Strength evolution in PM compacts as a function of sintering time and temperature: G.A.Soales. (USAF Academy, USA.)

Analysis of a water-propelled rocket: A problem in honors physics

The air-pumped, water-propelled rocket is a common child’s toy, yet forms a reasonably complicated system when carefully analyzed. A lab based on this system was included as the final laboratory project in the honors version of General Physics I at the USAF Academy. The numerical solution for the height of the rocket is presented, as well as several analytic approximations. Five out of six lab groups predicted the maximum height of the rocket within experimental error.

An Empirical Validation of Subjective Workload Ratings

A correlational design was used to regress NASA TLX subjective workload ratings onto several potential independent variables (i.e., the number of concurrent tasks, task combination, task resource demands, and flight experience) to determine task characteristics that influence pilot subjective workload ratings. A part task simulator was used to present up to six concurrent tasks, in different combinations, to 27 cadets at the USAF Academy. The results indicated the number of concurrent tasks had the largest impact on subjective workload ratings. In terms of multiple resource theory, spatial, verbal, and visual demands (in that order) contributed the most variance. The implication for theoreticians and designers is that the number of concurrent tasks, mental resource demands, and time constraints seem to be key contributors to subjective workload ratings.

The Prediction of Pilot Subjective Workload Ratings

This paper investigated potential variables that predict pilot subjective workload ratings. A correlational design was used to regress NASA TLX subjective workload ratings onto four independent variables (the number of concurrent tasks, task type, task combination, and flight experience). A pilot selection simulator was used to present five different flight tasks, in different combinations, to 15 cadets at the USAF Academy. The results indicated the number of concurrent tasks had the largest impact on subjective workload ratings, followed by subjects' flight experience. The data also showed that the effort dimension of the NASA TLX contributed the most variance to the overall weighted workload ratings. The implication for theoreticians and designers is that the number of concurrent tasks, experience, and perceived effort seem to be key contributor to subjective workload ratings.

Automated retinal robotic laser system.

Researchers at the University of Texas and the USAF Academy have worked toward the development of a retinal robotic laser system. The overall goal of this ongoing project is to precisely place and control the depth of laser lesions for the treatment of various retinal diseases such as diabetic retinopathy and retinal tears. Separate low speed prototype subsystems have been developed to control lesion depth using lesion reflectance feedback parameters and lesion placement using retinal vessels as tracking landmarks. Both subsystems have been successfully demonstrated in vivo on pigmented rabbits using an argon continuous wave laser. Recent efforts have concentrated on combining the two subsystems into a single prototype capable of simultaneously controlling both lesion depth and placement. We have designated this combined system CALOSOS for Computer Aided Laser Optics System for Ophthalmic Surgery. Following the dual-use concept, this system is being adapted for clinical use as a retinal treatment system as well as a research tool for military laser-tissue interaction studies.

Cognitive Styles and Feedback in Computer-Assisted Instruction

Feedback during student practice is considered a fundamental component of well-designed computer-assisted instruction (CAI). This project focuses on the appropriate applications of feedback in a CAI lesson which teaches knowledge bases and concepts. The student's learning style/characteristics are a factor in the process. The project follows a 4 × 2 design which includes a pretest, intervention, posttest, and delayed posttest model. The factors of the design are feedback (KCR, KCRI, KOR, KORI) and learner characteristics (field dependent, field independent). The learners, freshmen cadets at the USAF Academy, were assigned to treatment groups via stratified random sampling. Stratification was based on pretest scores of prior knowledge and learner characteristics. The results of the primary intervention, level of feedback, were statistically significant, favoring increasing levels of information feedback. This article also provides instructors, instructional designers and authors of computer-assisted instruction useful methodologies for implementing the results in instructional products.

Remarks delivered on behalf of the honorable Sheila E. Widnall, secretary of the Air Force

Remarks delivered on behalf of the honorable Sheila E. Widnall, secretary of the Air Force

Absolute stability of symmetric highly maneuverable missiles

References 1 Jines, L.A., The Air Force Ejection Seat as a Vehicle for Digital Flight Proceedings of the AIAA Guidance and Conference, Gatlinburg, Tenn., Aug. 1983, pp. Carroll, J.V., Control Law Design for Ejection Seats, Proceedings of the AIAA Guidance and Conference, Gatlinburg, Tenn., 1983, pp. Higgins, A.M., Catapult Dynamics in a High Acceleration Environment, USAF Academy, Colo. USAFA-TN-82-5, Oct. 1982. Brinkley, J.W. and Shaffer, J.T., Dynamic Simulation Techniques for the Design of Escape Systems: Current Applications and Furture Air Force Requirements, Symposium on Biodynamic Models and Their Applications, Wright-Patterson AFB, Ohio, AMRL-TR-71-29, Dec. 1971. Bryson, A.E. and Ho., Y.C., Applied Optimal Control, Hemisphere Publishing Co., Washington, D.C., 1975. Kelley, H.J., Kopp, R.E., and Moyer, G.H., Singular Extremals, Topics in Optimization, edited by G. Leitmann, Academic Press, New York, 1967. Neustadt, L., Synthesizing Time Optimal Controls, Journal of Mathematical Analysis and Applications, Vol. 1, 1960, p. 484.

USAF Academy Research Materials on American Flight, 1903–1927 From the Gimble Collection

USAF Academy Research Materials on American Flight, 1903–1927 From the Gimble Collection

Complex Design Projects for Teaching System Design

Frequently, undergraduates are exposed only to principles and concepts of HF engineering. However, the application of published guidelines will not answer all design questions. An HF course has been introduced at the USAF Academy which attempts to give the students design experience as well as exposing them to the complexities of design integration. The course is structured to parallel the design process and culminates in a final design project. Each class selected a major human-machine system. Then, each selected a subsystem for his/her individual project. First, students optimized the design of the selected subsystems. The second part of the project addressed the problem of system integration. Each class, as a group, evaluated trade-offs between subsystems to develop a coherent overall design. This type of exercise is recommended for educators trying to bridge the gap between the classroom and the reality of system design.

A Behaviorally Oriented Study Skills Program

A study skills program should have low time requirements, raise the student’s GPA, and create durable behaviors. Twenty-four male sophomore cadets at the USAF Academy were placed in one of two groups by their rank-order place on a list of academically deficient students. The experimental group and the control group both received normal directive counseling. The experimental group received a behaviorally oriented study skills program requiring two hours of supervisory time and minimal behavior recording and showed a mean increase of .54 GPA points; the control group showed an increase of .02 at the end of the semester. The results indicate this program satisfied the basic requirement of study skills training.

<title>A High Resolution Analog Fiber Optics Data Communications System</title>

A high resolution fiber optics communications system (FOCS) for analog signals has been designed, built, and tested at the Frank J. Seiler Research Laboratory, USAF Academy, Colorado. The FOCS consists of a small transmitter and receiver pair and an optical waveguide. A combination of voltage-to-voltage (V /F/V) and pulse width modulation (PWM) is used to reconstruct a ±1 0 volt analog output signal from an identical ±10 volt analog input signal. A digital output is easily obtained since the data transmission is pulsed. The FOCS is equally applicable to free-space infrared communications. The advantages of fiber optics have not previously been available for general purpose data acquisition because their application has been limited to dedicated digital systems and to low resolution, high frequency video systems. Data collected on a very general V/F/V system are presented to give the designer information on V/F/V system dynamics at fre-quencies much higher than those considered to be in the V /F /V system's useful range for data acquisition and communication purposes. These data show that the V/F/V process may be useful for servo loop applications at much higher frequencies than it is for data acquisition and communication applications.

The application of thermography to large arrays of solar energy collectors

The general principles of thermography are outlined and its application to solar energy research at the USAF Academy is discussed. Topics considered include the prediction and observation of flow problems within a large solar collector array, as well as the results of actions taken to alleviate them through the use of thermography. (SPH)

The Military and Society; Proceedings of the Fifth Military History Symposium, USAF Academy.

The Military and Society; Proceedings of the Fifth Military History Symposium, USAF Academy.