11,551 research outputs found
Yelling Fire and Hacking: Why the First Amendment Does Not Permit Distributing DVD Decryption Technology?
One of the consequences of the black-hole "no-hair" theorem in general relativity (GR) is that gravitational radiation (quasi-normal modes) from a perturbed Kerr black hole is uniquely determined by its mass and spin. Thus, the spectrum of quasi-normal mode frequencies have to be all consistent with the same value of the mass and spin. Similarly, the gravitational radiation from a coalescing binary black hole system is uniquely determined by a small number of parameters (masses and spins of the black holes and orbital parameters). Thus, consistency between different spherical harmonic modes of the radiation is a powerful test that the observed system is a binary black hole predicted by GR. We formulate such a test, develop a Bayesian implementation, demonstrate its performance on simulated data and investigate the possibility of performing such a test using previous and upcoming gravitational wave observations
Integral-equation methods in steady and unsteady subsonic, transonic and supersonic aerodynamics for interdisciplinary design
Progress in the development of computational methods for steady and unsteady aerodynamics has perennially paced advancements in aeroelastic analysis and design capabilities. Since these capabilities are of growing importance in the analysis and design of high-performance aircraft, considerable effort has been directed toward the development of appropriate aerodynamic methodology. The contributions to those efforts from the integral-equations research program at the NASA Langley Research Center is reviewed. Specifically, the current scope, progress, and plans for research and development for inviscid and viscous flows are discussed, and example applications are shown in order to highlight the generality, versatility, and attractive features of this methodology
Computational simulation of coupled material degradation processes for probabilistic lifetime strength of aerospace materials
The research included ongoing development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primative variables. These primative variable may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above described constitutive equation using actual experimental materials data together with linear regression of that data, thereby predicting values for the empirical material constraints for each effect or primative variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from the open literature for materials typically of interest to those studying aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology
The THUMOS Challenge on Action Recognition for Videos "in the Wild"
Automatically recognizing and localizing wide ranges of human actions has
crucial importance for video understanding. Towards this goal, the THUMOS
challenge was introduced in 2013 to serve as a benchmark for action
recognition. Until then, video action recognition, including THUMOS challenge,
had focused primarily on the classification of pre-segmented (i.e., trimmed)
videos, which is an artificial task. In THUMOS 2014, we elevated action
recognition to a more practical level by introducing temporally untrimmed
videos. These also include `background videos' which share similar scenes and
backgrounds as action videos, but are devoid of the specific actions. The three
editions of the challenge organized in 2013--2015 have made THUMOS a common
benchmark for action classification and detection and the annual challenge is
widely attended by teams from around the world.
In this paper we describe the THUMOS benchmark in detail and give an overview
of data collection and annotation procedures. We present the evaluation
protocols used to quantify results in the two THUMOS tasks of action
classification and temporal detection. We also present results of submissions
to the THUMOS 2015 challenge and review the participating approaches.
Additionally, we include a comprehensive empirical study evaluating the
differences in action recognition between trimmed and untrimmed videos, and how
well methods trained on trimmed videos generalize to untrimmed videos. We
conclude by proposing several directions and improvements for future THUMOS
challenges.Comment: Preprint submitted to Computer Vision and Image Understandin
The behavior of discounts of closed-end funds undergoing open-ending
Based on an extensive sample of U.S. closed-end funds undergoing open-ending conversion, we examine the behavior of discounts prior to the announcement till the date of open-ending. Discounts are significantly reduced upon announcement of open-ending with price increase. Announcement period return is directly related to the pre-announcement discount, liquidity, and other characteristics of the fund. We decompose the pre-announcement discount into structural and diosyncratic parts, and report that there is a greater reduction of the idiosyncratcic part of the discount. We examine the role of distributions to the investors on the size and behavior of discounts subsequent to the open-ending announcement. We find that small amounts of discounts remain at the time of the open-ending and investigate potential explanations for such discounts.closed-end funds, discount
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An Experiment with Flipped Classroom Concept in a Thermodynamics Course
Flipped classroom is an instructional concept that reverses the traditional method of teaching by providing instructional content in advance outside of the classroom and bringing some of the outside activities such as solving problems into the classroom. Flipped classroom concepts was recently experimented in two sections of an introductory undergraduate course in thermodynamics. Students were assigned to read specific sections of the textbook and review previously prepared power point presentation of lectures before attending lecture periods. Electronic respond devices, such as I-Clickers, were used to gage students understanding of assigned reading material by starting class with a quiz. The concepts were explained in detail. When students had difficulties with the specific topics related to quiz questions, a second quiz was given later to see if the students’ understanding of the material were improved. A survey was conducted near the end of semester to seek student feedback on their experience with the flipped classroom concept. The paper includes the results of the student survey.Cockrell School of Engineerin
Overcoming the Limitations of an Urban Setting Through Field-based Earth Systems Inquiry
Disconnection between students and nature in an urban setting thwarts student engagement and impedes geoscience teaching and learning. Conducting field trips is one way to engage students, but the urban environment does not provide an ideal setting with respect to the availability of appropriate field sites and safety. This text reports on a field-based inquiry project conducted in San Antonio, Texas. The project focused on Earth systems and system interactions, attempting to overcome the obstacles imposed by the urban environment by permitting teachers to focus on student observations and student initiated research questions rather than solely being limited to the use of text and laboratory activities. Educational levels: Graduate or professional
Computational simulation of probabilistic lifetime strength for aerospace materials subjected to high temperature, mechanical fatigue, creep and thermal fatigue
This report presents the results of a fourth year effort of a research program, conducted for NASA-LeRC by the University of Texas at San Antonio (UTSA). The research included on-going development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subject to a number of effects or primitive variables. These primitive variables may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above-described constitutive equation using actual experimental materials data together with regression analysis of that data, thereby predicting values for the empirical material constants for each effect or primitive variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from industry and the open literature for materials typically for applications in aerospace propulsion system components. Material data for Inconel 718 has been analyzed using the developed methodology
Open secrets
The law of trade secrets is often conceptualized in bilateral terms, as creating and enforcing rights between trade secret owners, on the one hand, and misappropriators on the other hand. This paper, a chapter in a forthcoming collection on the law of trade secrets, argues that trade secrets and the law that guards them can serve structural and institutional roles as well. Somewhat surprisingly, given the law’s focus on secrecy, among the institutional products of trade secrets law are commons, or managed openness: environments designed to facilitate the structured sharing of information. The paper illustrates with examples drawn from existing literature on cuisine, magic, and Internet search.
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