402 research outputs found
Linear Collider Collaboration Tech Notes Improved Overhead Accounting in the NLC Main Linac Improved Overhead Accounting in the NLC Main Linacs
No full textAbstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Improved Overhead Accounting in the NLC Main Linac Peter Tenenbaum June Improved Overhead Accounting in the NLC Main Linacs P. Tenenbaum LCC-Note-0148 June 9, 2004 Abstract The NLC main linac contains 1,116 RF power units, of which 5% are considered "spares" for replacement of failed power units, make-up of the energy gain during an RF breakdown, and energy feedback. A more careful accounting for the effects of beam loading indicates that the NLC can operate with less BNS overhead and a smaller mean phase offset than was originally specified, and that as a consequence the total number of spares is actually about 7.9% of the total
Hey, He Stole My Copyright: Putting Theft on Trial in the Tenenbaum Copyright Case
No full textThis article approaches the well-publicized Joel Tenenbaum copyright case through an analysis of its highly-charged trial rhetoric. In particular, it argues that the case as tried was not really about Joel Tenenbaum or his actions. Rather, the trial was about whether, and to what extent, peer-to-peer (“P2P”) file sharing is “theft,” and the P2P sharer a “thief.” So approached, the case provides a captivating, perhaps unique, academic case study on the power of theft rhetoric in a copyright trial as advanced before a jury.
It first introduces the Tenenbaum litigation generally, and its place in the recording companies’ broad attack on P2P file-sharing. Next, it shows how the rhetoric of theft pervaded the trial to such a degree that the file-sharing-as-theft metaphor itself became the central figure in the drama. By closing arguments, the parties were effectively asking the jury to decide not whether Tenenbaum was liable for copyright infringement, which was not even in dispute, but whether Tenenbaum’s infringement amounted to copyright theft. Then, working off of the framework for defining “theft” of intellectual property developed by Prof. Stuart Green in his recent theoretical treatise on theft law, 13 Ways to Steal a Bicycle, the article asks expressly the question implicit in the Tenenbaum case. Namely, did plaintiffs succeed in showing that Tenenbaum “stole” the copyright in the thirty songs at issue? It finds that while the plaintiffs shaped their arguments in such a way as to justify the conclusion that P2P file-sharers, working in the aggregate, could effectively steal a copyright, they failed to make such a case as against Tenenbaum individually.
The article then observes that whatever theoretical flaws there might be in the theft narrative and Tenenbaum outcome, the trial provides confirmation that the industry’s long campaign to promote the file-sharer-as-thief metaphor gained traction with the public. It at least primed the jury for the rhetoric advanced in the case. As between the two narratives on trial — theft and not-theft — the former best explains the jury’s verdict. Nevertheless, in the final analysis, the plaintiffs “won” little of value in the Tenenbaum case. It was ultimately a symbolic litigation that never should have happened in the first place
Self-trapping of infrared energy absorbed in acetanilide
No full textAcetanilide (ACN) has an anomalous low temperature IR absorption band, which has been attributed to a self-trapped state of molecular vibrational energy in the amide group (Davydov-like soliton). A classical model for a segment of an ACN chain has been set up, taking into account the degrees of freedom of the amide group involved in the H-bond: stretching of C=O bond, stretching and bending of the H-bond. The dynamics of the molecule has been investigated by molecular dynamics simulation
Physical reasoning in complex scenes is sensitive to mass
No full text<p>Hamrick, J. B., Battaglia, P. W., & Tenenbaum, J. B. (2012, May). Physical reasoning in complex scenes is sensitive to mass. Poster presented at the Annual Meeting of the Vision Sciences Society. Naples, FL.</p
Simulation as an engine of physical scene understanding
No full textIn a glance, we can perceive whether a stack of dishes will topple, a branch will support a child’s weight, a grocery bag is poorly packed and liable to tear or crush its contents, or a tool is firmly attached to a table or free to be lifted. Such rapid physical inferences are central to how people interact with the world and with each other, yet their computational underpinnings are poorly understood. We propose a model based on an “intuitive physics engine,” a cognitive mechanism similar to computer engines that simulate rich physics in video games and graphics, but that uses approximate, probabilistic simulations to make robust and fast inferences in complex natural scenes where crucial information is unobserved. This single model fits data from five distinct psychophysical tasks, captures several illusions and biases, and explains core aspects of human mental models and common-sense reasoning that are instrumental to how humans understand their everyday world.National Institutes of Health (U.S.) (5F32EY019228-02)United States. Office of Naval Research (Grant N00014-09-0124)United States. Office of Naval Research (Grant N00014-07-1-0937)United States. Office of Naval Research (Grant 1015GNA126)QUALCOMM Inc.United States. Intelligence Advanced Research Projects Activity (Grant D10PC20023
Small Gál sums and applications
No full textIn recent years, maximizing Gál sums regained interest due to a firm link with large values of (Formula presented.) -functions. In the present paper, we initiate an investigation of small sums of Gál type, with respect to the (Formula presented.) -norm. We also consider the intertwined question of minimizing weighted versions of the usual multiplicative energy. We apply our estimates to: (i) a logarithmic refinement of Burgess' bound on character sums, improving previous results of Kerr, Shparlinski and Yau; (ii) an improvement on earlier lower bounds by Louboutin and the second author for the number of nonvanishing theta functions associated to Dirichlet characters; and (iii) new lower bounds for low moments of character sums
sj-pdf-1-amp-10.1177_25152459221147250 – Supplemental material for iCatcher+: Robust and Automated Annotation of Infants’ and Young Children’s Gaze Behavior From Videos Collected in Laboratory, Field, and Online Studies
No full textSupplemental material, sj-pdf-1-amp-10.1177_25152459221147250 for iCatcher+: Robust and Automated Annotation of Infants’ and Young Children’s Gaze Behavior From Videos Collected in Laboratory, Field, and Online Studies by Yotam Erel, Katherine Adams Shannon, Junyi Chu, Kim Scott, Melissa Kline Struhl, Peng Cao, Xincheng Tan, Peter Hart, Gal Raz, Sabrina Piccolo, Catherine Mei, Christine Potter, Sagi Jaffe-Dax, Casey Lew-Williams, Joshua Tenenbaum, Katherine Fairchild, Amit Bermano and Shari Liu in Advances in Methods and Practices in Psychological Science</p
Spontaneous Pneumomediastinum as a Potential Predictor of Mortality in Patients with Idiopathic Pulmonary Fibrosis
No full textBackground: Spontaneous pneumomediastinum (PM) is a rare event in patients with idiopathic pulmonary fibrosis (IPF) with unknown prognostic implications. Objectives: To analyze the incidence and prognostic impact of PM in a cohort of patients with IPF. Methods: PM diagnosed by computed tomography was identified retrospectively in the clinical and radiological records of 182 patients with IPF who were admitted to our center between August 2006 and July 2013. PM patients were compared to matched IPF patients not affected by PM and analyzed for survival. Results: PM occurred in 9/182 IPF patients [5%; 6 males; median age: 63 years; median percent predicted of vital capacity (VC%) at baseline: 53%]. The median time between IPF diagnosis and PM occurrence was 3 months (interquartile range: 0-33). The control group included 36 IPF patients (28 males; median age: 69 years; VC% at baseline: 57%). In a multivariate Cox regression analysis, PM was a significant predictor of mortality [hazard ratio (HR): 3.0; p = 0.032]. Considering only patients experiencing PM at the time of IPF diagnosis (n = 4), PM was a strongly significant predictor of mortality in multivariate analysis (HR: 6.4; p = 0.007). Conclusions: Spontaneous PM is a rare but serious complication in patients with IPF and may be considered as a potential predictor of mortality
A rational choice framework for collective behavior
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 137-146).As the world becomes increasingly digitally mediated, people can more and more easily form groups, teams, and communities around shared interests and goals. Yet there is a constant struggle across forms of social organization to maintain stability and coherency in the face of disparate individual experiences and agendas. When are collectives able to function and thrive despite these challenges? In this thesis I propose a theoretical framework for reasoning about collective intelligence--the ability of people to accomplish their shared goals together. A simple result from the literature on multiagent systems suggests that strong general collective intelligence in the form of "rational group agency" arises from three conditions: aligned utilities, accurate shared beliefs, and coordinated actions. However, achieving these conditions can be difficult, as evidenced by impossibility results related to each condition from the literature on social choice, belief aggregation, and distributed systems. The theoretical framework I propose serves as a point of inspiration to study how human groups address these difficulties. To this end, I develop computational models of facets of human collective intelligence, and test these models in specific case studies. The models I introduce suggest distributed Bayesian inference as a framework for understanding shared belief formation, and also show that people can overcome other difficult computational challenges associated with achieving rational group agency, including balancing the group "exploration versus exploitation dilemma" for information gathering and inferring levels of "common p-belief" to coordinate actions.by Peter M. Krafft.Ph. D
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