A representation-free description of the Kasevich-Chu interferometer: a resolution of the redshift controversy

Motivated by a recent claim by Muller et al (2010 Nature 463 926-9) that an atom interferometer can serve as an atom clock to measure the gravitational redshift with an unprecedented accuracy, we provide a representation-free description of the Kasevich-Chu interferometer based on operator algebra. We use this framework to show that the operator product determining the number of atoms at the exit ports of the interferometer is a c-number phase factor whose phase is the sum of only two phases: one is due to the acceleration of the phases of the laser pulses and the other one is due to the acceleration of the atom. This formulation brings out most clearly that this interferometer is an accelerometer or a gravimeter. Moreover, we point out that in different representations of quantum mechanics such as the position or the momentum representation the phase shift appears as though it originates from different physical phenomena. Due to this representation dependence conclusions concerning an enhanced accuracy derived in a specific representation are unfounded.

Interest Representation as a Clash of Unequal Allies

Organized interests do not have direct control over the fate of their policy agendas in Congress. They cannot introduce bills, vote on legislation, or serve on House committees. If organized interests want to achieve virtually any of their legislative goals they must rely on and work through members of Congress. As an interest group seeks to move its policy agenda forward in Congress, then, one of the most important challenges it faces is the recruitment of effective legislative allies. Legislative allies are members of Congress who “share the same policy objective as the group” and who use their limited time and resources to advocate for the group’s policy needs (Hall and Deardorff 2006, 76). For all the financial resources that a group can bring to bear as it competes with other interests to win policy outcomes, it will be ineffective without the help of members of Congress that are willing to expend their time and effort to advocate for its policy positions (Bauer, Pool, and Dexter 1965; Baumgartner and Leech 1998b; Hall and Wayman 1990; Hall and Deardorff 2006; Hojnacki and Kimball 1998, 1999). Given the importance of legislative allies to interest group success, are some organized interests better able to recruit legislative allies than others? This question has received little attention in the literature. This dissertation offers an original theoretical framework describing both when we should expect some types of interests to generate more legislative allies than others and how interests vary in their effectiveness at mobilizing these allies toward effective legislative advocacy. It then tests these theoretical expectations on variation in group representation during the stage in the legislative process that many scholars have argued is crucial to policy influence, interest representation on legislative committees. The dissertation uncovers pervasive evidence that interests with a presence across more congressional districts stand a better chance of having legislative allies on their key committees. It also reveals that interests with greater amounts of leverage over jobs and economic investment will be better positioned to win more allies on key committees. In addition, interests with a policy agenda that closely overlaps with the jurisdiction of just one committee in Congress are more likely to have legislative allies on their key committees than are interests that have a policy agenda divided across many committee jurisdictions. In short, how groups are distributed across districts, the leverage that interests have over local jobs and economic investment, and how committee jurisdictions align with their policy goals affects their influence in Congress.

CIL I(2): 2.1, 931 – Consular tesserae

Photograph and notes by A.E. Gordon

CIL 3.7222 – Fragment of a consular dedication

Photograph with notes by A.E. Gordon

Criteria for graphic representation in musical scores: Visual elements in musical scores

A interdisciplinaridade entre a música e as artes visuais tem sido explorado por conceituados teóricos e filósofos, embora não exista muito na área da interpretação visual do grafismo de partituras musicais. Este estudo investiga como os grafismos na notação e símbolos musicais afectam o intérprete na sua transformação em som, com referência especial a partituras contemporâneas, que utilizam notação menos convencional para a criação de uma interpretação por sugestão. Outras relações entre o som e o visual são exploradas, incluindo a sinestesia, a temporalidade e a relação entre obra de arte e público. O objectivo desta dissertação é a de constituir um estudo inovativo sobre partituras musicais contemporâneas, simultaneamente do ponto de vista musical e visual. Finalmente, também vai mais longe, incluindo desenhos da própria autora inspirados e motivados pela música. Estes já não cumprem uma função de notação convencional para o músico, embora existe uma constante possibilidade de uma reinterpretação. ABSTRACT; The inter-disciplinarity between music and visual art has been explored by leading theorists and philosophers, though very little exists in the area of the visual interpretation of graphic musical scores. This study looks at how the graphics of musical notation and symbols affect the performer in transforming them into sound, with particular reference to contemporary scores that use non¬conventional notation to create an interpretation through suggestion. Other sound-visual relationships are explored, including synaesthesia, temporality and the interconnection between work of art and audience or public. This dissertation aims to be an innovative study of contemporary musical scores, from a musical as well as visual perspective. Finally, it takes a step further with drawings of my own, directly inspired and motivated by the music. These no longer fulfil a conventionally notational function for the musician, yet the potential for a re-interpretation is ever-present.

A three-dimensional representation method for noisy point clouds based on growing self-organizing maps accelerated on GPUs

The research described in this thesis was motivated by the need of a robust model capable of representing 3D data obtained with 3D sensors, which are inherently noisy. In addition, time constraints have to be considered as these sensors are capable of providing a 3D data stream in real time. This thesis proposed the use of Self-Organizing Maps (SOMs) as a 3D representation model. In particular, we proposed the use of the Growing Neural Gas (GNG) network, which has been successfully used for clustering, pattern recognition and topology representation of multi-dimensional data. Until now, Self-Organizing Maps have been primarily computed offline and their application in 3D data has mainly focused on free noise models, without considering time constraints. It is proposed a hardware implementation leveraging the computing power of modern GPUs, which takes advantage of a new paradigm coined as General-Purpose Computing on Graphics Processing Units (GPGPU). The proposed methods were applied to different problem and applications in the area of computer vision such as the recognition and localization of objects, visual surveillance or 3D reconstruction.

The Drama of History: Representation and Revolutionaries in Haitian Theater, 1818-1907

Since the beginning of the Haitian theatrical tradition there has been an ineluctable dedication to the representation of Haitian history on stage. Given the rich theatrical archive about Haiti throughout the world, this study considers operas and plays written solely by Haitian playwrights. By delving into the works of Juste Chanlatte, Massillon Coicou, and Vendenesse Ducasse this study proposes a re-reading of Haitian theater that considers the stage as an innovative site for contesting negative and clichéd representations of the Haitian Revolution and its revolutionary leadership. A genre long mired in accusations of mimicking European literary forms, this study proposes a reevaluation of Haitian theater and its literary origins.

X-ray vision: mental representation of the human body’s inner morphology

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Contributions to 3D Data Registration and Representation

Nowadays, new computers generation provides a high performance that enables to build computationally expensive computer vision applications applied to mobile robotics. Building a map of the environment is a common task of a robot and is an essential part to allow the robots to move through these environments. Traditionally, mobile robots used a combination of several sensors from different technologies. Lasers, sonars and contact sensors have been typically used in any mobile robotic architecture, however color cameras are an important sensor due to we want the robots to use the same information that humans to sense and move through the different environments. Color cameras are cheap and flexible but a lot of work need to be done to give robots enough visual understanding of the scenes. Computer vision algorithms are computational complex problems but nowadays robots have access to different and powerful architectures that can be used for mobile robotics purposes. The advent of low-cost RGB-D sensors like Microsoft Kinect which provide 3D colored point clouds at high frame rates made the computer vision even more relevant in the mobile robotics field. The combination of visual and 3D data allows the systems to use both computer vision and 3D processing and therefore to be aware of more details of the surrounding environment. The research described in this thesis was motivated by the need of scene mapping. Being aware of the surrounding environment is a key feature in many mobile robotics applications from simple robotic navigation to complex surveillance applications. In addition, the acquisition of a 3D model of the scenes is useful in many areas as video games scene modeling where well-known places are reconstructed and added to game systems or advertising where once you get the 3D model of one room the system can add furniture pieces using augmented reality techniques. In this thesis we perform an experimental study of the state-of-the-art registration methods to find which one fits better to our scene mapping purposes. Different methods are tested and analyzed on different scene distributions of visual and geometry appearance. In addition, this thesis proposes two methods for 3d data compression and representation of 3D maps. Our 3D representation proposal is based on the use of Growing Neural Gas (GNG) method. This Self-Organizing Maps (SOMs) has been successfully used for clustering, pattern recognition and topology representation of various kind of data. Until now, Self-Organizing Maps have been primarily computed offline and their application in 3D data has mainly focused on free noise models without considering time constraints. Self-organising neural models have the ability to provide a good representation of the input space. In particular, the Growing Neural Gas (GNG) is a suitable model because of its flexibility, rapid adaptation and excellent quality of representation. However, this type of learning is time consuming, specially for high-dimensional input data. Since real applications often work under time constraints, it is necessary to adapt the learning process in order to complete it in a predefined time. This thesis proposes a hardware implementation leveraging the computing power of modern GPUs which takes advantage of a new paradigm coined as General-Purpose Computing on Graphics Processing Units (GPGPU). Our proposed geometrical 3D compression method seeks to reduce the 3D information using plane detection as basic structure to compress the data. This is due to our target environments are man-made and therefore there are a lot of points that belong to a plane surface. Our proposed method is able to get good compression results in those man-made scenarios. The detected and compressed planes can be also used in other applications as surface reconstruction or plane-based registration algorithms. Finally, we have also demonstrated the goodness of the GPU technologies getting a high performance implementation of a CAD/CAM common technique called Virtual Digitizing.

Innovative ways of knowledge representation and management

Knowledge is the key for success. The adequate treatment you make on data for generating knowledge can make a difference in projects, processes, and networks. Such a treatment is the main goal of two important areas: knowledger representation and management. Our aim, in this book, is collecting sorne innovative ways of representing and managing knowledge proposed by several Latin American researchers under the premise of improving knowledge.

Beneath the surface of the heritage enterprise. Governmentality and cultural representation of rural architecture in Portugal

This article focuses on the construction of heritage in rural Portugal. Drawing on anthropological fieldwork in the village of Castelo Rodrigo, it analyses the extensive protection and exhibition of domestic architecture in the framework of a State-led local development programme. By bringing in the messiness of daily practices, the article goes beyond neat theoretical formulations in the study of heritage such as Foucault’s theory of “governmentality” and Kirshenblatt-Gimblett’s notion of “second life as heritage”. It argues that the “conduct of conduct” is actually nowhere near as effective as its theoretical formulation might have us believe, and the second life as heritage suffocates the first life of houses as social habitats for the village population.

The ins and outs of biosecurity: bird 'flu in East Anglia and the spatial representation of risk

Avian influenza, or 'bird 'flu' arrived in Norfolk in April 2006 in the form of the low pathogenic strain H7N3. In February 2007 a highly pathogenic strain, H5N1, which can pose a risk to humans, was discovered in Suffolk. We examine how a local newspaper reported the outbreaks, focusing on the linguistic framing of biosecurity. Consistent with the growing concern with securitisation among policymakers, issues were discussed in terms of space (indoor–outdoor; local–global; national–international) and flows (movement, barriers and vectors) between spaces (farms, sheds and countries). The apportioning of blame along the lines of 'them and us'– Hungary and England – was tempered by the reporting on the Hungarian operations of the British poultry company. Explanations focused on indoor and outdoor farming and alleged breaches of biosecurity by the companies involved. As predicted by the idea of securitisation, risks were formulated as coming from outside the supposedly secure enclaves of poultry production.

Bahadur representation of linear kernel quantile estimator of VaR under mixing assumptions

Bahadur representation and its applications have attracted a large number of publications and presentations on a wide variety of problems. Mixing dependency is weak enough to describe the dependent structure of random variables, including observations in time series and longitudinal studies. This note proves the Bahadur representation of sample quantiles for strongly mixing random variables (including ½-mixing and Á-mixing) under very weak mixing coe±cients. As application, the asymptotic normality is derived. These results greatly improves those recently reported in literature.

Efficient representation of texture details in medical images by fusion of Ripplet and DDCT transformed images

Purpose: To evaluate and compare the performance of Ripplet Type-1 transform and directional discrete cosine transform (DDCT) and their combinations for improved representation of MRI images while preserving its fine features such as edges along the smooth curves and textures. Methods: In a novel image representation method based on fusion of Ripplet type-1 and conventional/directional DCT transforms, source images were enhanced in terms of visual quality using Ripplet and DDCT and their various combinations. The enhancement achieved was quantified on the basis of peak signal to noise ratio (PSNR), mean square error (MSE), structural content (SC), average difference (AD), maximum difference (MD), normalized cross correlation (NCC), and normalized absolute error (NAE). To determine the attributes of both transforms, these transforms were combined to represent the entire image as well. All the possible combinations were tested to present a complete study of combinations of the transforms and the contrasts were evaluated amongst all the combinations. Results: While using the direct combining method (DDCT) first and then the Ripplet method, a PSNR value of 32.3512 was obtained which is comparatively higher than the PSNR values of the other combinations. This novel designed technique gives PSNR value approximately equal to the PSNR’s of parent techniques. Along with this, it was able to preserve edge information, texture information and various other directional image features. The fusion of DDCT followed by the Ripplet reproduced the best images. Conclusion: The transformation of images using Ripplet followed by DDCT ensures a more efficient method for the representation of images with preservation of its fine details like edges and textures.