Generalized sampling interpolation of noisy gravity/gravity gradient data

The generalized sampling expansion (GSE) has been shown as a method for successfully interpolating combined gravity and gravity gradient data sets when the data are undersampled. The presence of noise on data sets renders such interpolation more difficult and many applications (known as expansions) of the GSE can be shown to intolerably amplify noise. However, many key expansions can be shown to successfully interpolate noisy data and even, given limited gradient error and sufficiently narrow line-spacing, reduce noise. These results can be shown to hold for both random noise and along-line correlated (levelling error type) noise. Unfortunately, the only expansion capable of interpolating a data set sampled at 3× conventional line-spacing, the Three-rectangle expansion, has a poor noise response and always acts to amplify data error. The GSE method bares up well against other methods of gradient enhanced interpolation; in numerical tests several expansions for the gravity field produce less noisy output than any of the pseudo-line, gradient enhanced minimum curvature or gradient enhanced Akima spline methods. Despite edge effects and using only gradient data with no gravity component, the GSE applied to real undersampled survey data bares up well against conventional interpolation, reducing noise where the data are clearly undersample

Overview of the Tevatron Collider Complex: Goals, Operations and Performance

For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatron's operational history, and briefly describe operations of each accelerator in the chain and achieved performance.Comment: Includes modifications suggested by reviewer

Innovative, High-Pressure, Cryogenic Control Valve: Short Face-to-Face, Reduced Cost

A control valve that can throttle high-pressure cryogenic fluid embodies several design features that distinguish it over conventional valves designed for similar applications. Field and design engineers worked together to create a valve that would simplify installation, trim changes, and maintenance, thus reducing overall cost. The seals and plug stem packing were designed to perform optimally in cryogenic temperature ranges. Unlike conventional high-pressure cryogenic valves, the trim size can be changed independent of the body

Beautiful Brown Eyes

Photograph of Joan Edwards; Illustration of music notehttps://scholarsjunction.msstate.edu/cht-sheet-music/8993/thumbnail.jp

Subduction and vertical coastal motions in the eastern Mediterranean

Convergence in the eastern Mediterranean of oceanic Nubia with Anatolia and the Aegean is complex and poorly understood. Large volumes of sediment obscure the shallow structure of the subduction zone, and since much of the convergence is accommodated aseismically, there are limited earthquake data to constrain its kinematics. We present new source models for recent earthquakes, combining these with field observations, published GPS velocities and reflection-seismic data to investigate faulting in three areas: the Florence Rise, SW Turkey and the Pliny and Strabo Trenches. The depths and locations of earthquakes reveal the geometry of the subducting Nubian plate NE of the Florence Rise, a bathymetric high that is probably formed by deformation of sediment at the surface projection of the Anatolia–Nubia subduction interface. In SW Turkey, the presence of a strike-slip shear zone has often been inferred despite an absence of strike-slip earthquakes. We show that the GPS-derived strain-rate field is consistent with extension on the orthogonal systems of normal faults observed in the region and that strike-slip faulting is not required to explain observed GPS velocities. Further SW, the Pliny and Strabo Trenches are also often interpreted as strike-slip shear zones, but almost all nearby earthquakes have either reverse-faulting or normal-faulting focal mechanisms. Oblique convergence across the trenches may be accommodated either by a partitioned system of strike-slip and reverse faults or by oblique slip on the Aegean–Nubia subduction interface. The observed late-Quaternary vertical motions of coastlines close to the subduction zone are influenced by the interplay between: (1) thickening of the material overriding the subduction interface associated with convergence, which promotes coastal uplift; and (2) subsidence due to extension and associated crustal thinning. Long-wavelength gravity data suggest that some of the observed topographic contrasts in the eastern Mediterranean are supported by mantle convection. However, whether the convection is time dependent and whether its pattern moves relative to Nubia are uncertain, and its contribution to present-day rates of vertical coastal motions is therefore hard to constrain. The observed extension of the overriding material in the subduction system is probably partly related to buoyancy forces arising from topographic contrasts between the Aegean, Anatolia and the Mediterranean seafloor, but the reasons for regional variations are less clear

The Design and Creation of an Interactive E-Book: "Book of Answer"

Interactive E-book is a digital book which the reader can direct the storyline and interact with it. 'The book of answer' is a kind of popular book that reader can interact with. In this project, we aim to develop an PVE game to simulating the process that the reader interact with the computer with the content of the book saved in. We use Python to realize the interactive dialogue process in GUI (Graphical User Interface).https://doi.org/10.1088/1742-6596/1187/5/05201

Network Creation Games: Think Global - Act Local

We investigate a non-cooperative game-theoretic model for the formation of communication networks by selfish agents. Each agent aims for a central position at minimum cost for creating edges. In particular, the general model (Fabrikant et al., PODC'03) became popular for studying the structure of the Internet or social networks. Despite its significance, locality in this game was first studied only recently (Bil\`o et al., SPAA'14), where a worst case locality model was presented, which came with a high efficiency loss in terms of quality of equilibria. Our main contribution is a new and more optimistic view on locality: agents are limited in their knowledge and actions to their local view ranges, but can probe different strategies and finally choose the best. We study the influence of our locality notion on the hardness of computing best responses, convergence to equilibria, and quality of equilibria. Moreover, we compare the strength of local versus non-local strategy-changes. Our results address the gap between the original model and the worst case locality variant. On the bright side, our efficiency results are in line with observations from the original model, yet we have a non-constant lower bound on the price of anarchy.Comment: An extended abstract of this paper has been accepted for publication in the proceedings of the 40th International Conference on Mathematical Foundations on Computer Scienc

A POLITICAL LANDSCAPE OF STREET TRADER ORGANISATIONS IN INNER CITY JOHANNESBURG, POST OPERATION CLEAN SWEEP

Most international academic literature hardly considers street trader organisations as an object of research. Street trading organisations are often too fragmented and fragile, too locally focused and politically weak, too short lived or fluid, to be construed as an authentic “social movement” – whatever it may mean. Furthermore, they are seen as representing the tip of the iceberg, focusing mostly on legal traders and protecting those traders’ (legitimate but narrow) interests, while ignoring a majority of traders who adopt other types of politics. It is relatively recently perhaps that scholars have highlighted the “changing politics” of informality, and paid more attention to the collective agency of informal traders conceptualised as “workers” (Lindell 2010a).It is more than a year after Operation Clean Sweep, where in October 2013 the City of Johannesburg brutally evicted all traders from the streets of inner city Johannesburg. Most of these traders did not belong to street trading organisations, did not have an easy recourse to a language of “rights” as most of them were trading “illegally” in the inner city. Most of them were not organised neither making collective claims, but were used to adopting a politics of invisibility, of every day arrangements and constant mobility. In this context, what is the relevance of street trading organisations: why this research? The response to this question is three-fold. First, street trading organisations seem to be the victim of a double prejudice: a political one, that discards their leadership as opportunistic, their protests as “popcorn”, their organisations as “fly-by-night”, un-representative and irremediably divided. And, to a lesser extent, there is also an academic prejudice against street trading organisations, not considered as forming an authentic “social movement”, or at least seldom included in this field of study (see for instance a number of books devoted to social movements in South Africa - Ballard et al. 2006; Dawson and Sinwell 2012): because of their divisions, their lack of clear -let alone radical- ideological position, and their intrinsic fragility and fluidity. Yet, street trader organisations persist

Selfish Network Creation with Non-Uniform Edge Cost

Network creation games investigate complex networks from a game-theoretic point of view. Based on the original model by Fabrikant et al. [PODC'03] many variants have been introduced. However, almost all versions have the drawback that edges are treated uniformly, i.e. every edge has the same cost and that this common parameter heavily influences the outcomes and the analysis of these games. We propose and analyze simple and natural parameter-free network creation games with non-uniform edge cost. Our models are inspired by social networks where the cost of forming a link is proportional to the popularity of the targeted node. Besides results on the complexity of computing a best response and on various properties of the sequential versions, we show that the most general version of our model has constant Price of Anarchy. To the best of our knowledge, this is the first proof of a constant Price of Anarchy for any network creation game.Comment: To appear at SAGT'1