4,642 research outputs found

    aDORe djatoka: An Open-Source Jpeg 2000 Image Server and Dissemination Service Framework

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    4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-05-19 03:00 PM – 04:30 PMThe JPEG 2000 image format has attracted considerable attention due to its rich feature set defined in a multi-part open ISO standard, and its potential use as a holy-grail preservation format providing both lossless compression and rich service format features. Until recently there was lack of an implementation agnostic (e.g., Kakadu, Aware, etc) API for JPEG 2000 compression and extraction, and an open-source service framework, upon which rich Web 2.0-style applications can be developed. Recently we engaged in the development of aDORe djatoka , an open-source JPEG 2000 image server and dissemination framework to help address some of these issues. The djatoka image server is geared towards Web 2.0 style reuse through URI-addressability of all image disseminations including regions, rotations, and format transformations. Djatoka also provides a JPEG 2000 compression / extraction API that serves as an abstraction layer from the underlying JPEG 2000 library (e.g., Kakadu, Aware, etc).  The initial release has attracted considerable interest and is already being used in production environments, such as at the Biodiversity Heritage Library , who uses djatoka to serve more than eleven million images. This presentation introduces the aDORe djatoka image server and describes various interoperability approaches with existing repository systems.  Djatoka was derived from a concrete need to introduce a solution to disseminate high-resolution images stored in an aDORe repository system.  Djatoka is able to disseminate images that reside either in a repository environment or that are Web-accessible at arbitrary URIs.  Since dynamic service requests pertaining to an identified resource (the entire JPEG 2000 image) are being made, the OpenURL Framework was selected to provide an extensible dissemination service framework. The OpenURL service layer simplifies development and provides exciting interoperability opportunities. The presentation will showcase the flexibility of this interface by introducing a mobile image collection viewer developed for the iPhone / iTouch platform

    Overview of Altair's Thermal Control System and the Associated Technology Development Efforts

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    Abstract In early 2004, President Bush announced a bold vision for space exploration. One of the goals included in this vision is a return to the moon by 2020. In response to this vision, NASA established the Constellation Program, which includes several project offices. One of the Constellation projects is Altair, which is the next generation Lunar Lander. The future Altair missions are very different than the Lunar missions accomplished during the Apollo era. As such, there are several project risks and design challenges that have never before been addressed. Due to the unique thermal environment associated with this mission, many of these risks and design challenges are associated with the vehicle's thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The current paper will summarize the Altair mission profile, the operational phases, and the thermal design challenges unique to this particular vehicle. The paper will also describe the technology development efforts being performed to mitigate the risks and design challenges. The technology development project is performing a rigorous development effort that includes thermal control system fluids, evaporators, heat exchangers, and Lunar surface radiators. Constellation Program, there are several project offices. One of these projects includes the development of NASA's new lunar lander vehicle. The overall mission architecture for this vehicle, Altair, is very similar to Apollo's architecture. This paper will provide the reader with an overview of the Altair vehicle. In addition, Altair's thermal control system, including the functionality and the hardware, will be discussed. The paper will also describe the technology development process and the various technology developments currently underway

    Overview of the Altair Lunar Lander Thermal Control System Design and the Impacts of Global Access

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    NASA's Constellation Program (CxP) was developed to successfully return humans to the Lunar surface prior to 2020. The CxP included several different project offices including Altair, which was planned to be the next generation Lunar Lander. The Altair missions were architected to be quite different than the Lunar missions accomplished during the Apollo era. These differences resulted in a significantly dissimilar Thermal Control System (TCS) design. The current paper will summarize the Altair mission architecture and the various operational phases associated with the planned mission. In addition, the derived thermal requirements and the TCS designed to meet these unique and challenging thermal requirements will be presented. During the past year, the design team has focused on developing a vehicle architecture capable of accessing the entire Lunar surface. Due to the widely varying Lunar thermal environment, this global access requirement resulted in major changes to the thermal control system architecture. These changes, and the rationale behind the changes, will be detailed throughout the current paper

    Overview of NASA's Thermal Control System Development for Exploration Project

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    NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several sub-elements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The risks and design challenges are addressed through a rigorous technology development process that culminates with an integrated thermal control system test. The resulting hardware typically has a Technology Readiness Level (TRL) of six. This paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing assessments for thermal control system fluids

    A spectral regularisation framework for latent variable models designed for single channel applications

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    Latent variable models (LVMs) are commonly used to capture the underlying dependencies, patterns, and hidden structure in observed data. Source duplication is a by-product of the data hankelisation pre-processing step common to single channel LVM applications, which hinders practical LVM utilisation. In this article, a Python package titled spectrally-regularised-LVMs is presented. The proposed package addresses the source duplication issue via the addition of a novel spectral regularisation term. This package provides a framework for spectral regularisation in single channel LVM applications, thereby making it easier to investigate and utilise LVMs with spectral regularisation. This is achieved via the use of symbolic or explicit representations of potential LVM objective functions which are incorporated into a framework that uses spectral regularisation during the LVM parameter estimation process. The objective of this package is to provide a consistent linear LVM optimisation framework which incorporates spectral regularisation and caters to single channel time-series applications.Comment: 15 pages; 6 figures; 1 table; github; submitted to Software

    University food environment, an example of health inequality?

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    Background: Universities provide an influential life structure for students during their transition into adulthood through tuition as well as through the ground’s environment. Ensuring a healthy and safe university environment forms the basis of health equity within such institutions. The objective was to evaluate the food environment through vending machines situated across the grounds of the only state university in Malta, whilst acquiring students’ perspective on these facilities. Method: An audit was conducted on the food and beverage items available within vending machines across university grounds. This was reevaluated a year later. Students’ perceptions and use of such facilities were gathered through electronic-distributed questionnaires. Results: All machines were stocked with identical sugary items. 71.03% of responders purchased from machines due to their easy accessibility, while 61% considered items as “too unhealthy”, with 74.60% showing enthusiasm for healthier choices. 60% reported a willingness to pay more in exchange for healthier options. Conclusion: Limited consumable options leave students without healthier options on campus. Provision of a healthier food environment is a prerequisite in addressing health inequalities. Action is required to tackle this situation urgently especially due to the growing obesity epidemic.peer-reviewe

    Land Acquisitions in Africa: A Return to Franz Fanon?

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    In order to understand the predicament facing Africa today, one has to return to a previous era when Africa faced its fight against colonalization. One hundred and twenty-five years after the Berlin Conference, a vast majority of African states remain in a position of social and political stagnation. Decolonization, which was supposedly based on the positive-sum incorporation of the newly-independent states into the international political arena, led to the dissolution of the rhetoric of “civilizing the barbaric masses”; and a new global endeavor emerged to “develop” the post-colonial state via its access to the absolute gains of the global political economy. For the majority of populaces of the Third World, however, the promises of social security, economic advancement, equal terms of trade, and the abandonment of force and racism did not shadow the decolonization process. In this context, Franz Fanon said that there is nothing save a minimum of re-adaptation, a few reforms at the top, a flag waving, and down at the bottom an undivided mass still living in the middle ages, endlessly marking time

    Why Are There Descriptive Norms? Because We Looked for Them

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    In this work, we present a mathematical model for the emergence of descriptive norms, where the individual decision problem is formalized with the standard Bayesian belief revision machinery. Previous work on the emergence of descriptive norms has relied on heuristic modeling. In this paper we show that with a Bayesian model we can provide a more general picture of the emergence of norms, which helps to motivate the assumptions made in heuristic models. In our model, the priors formalize the belief that a certain behavior is a regularity. The evidence is provided by other group members’ behavior and the likelihood by their reliability. We implement the model in a series of computer simulations and examine the group-level outcomes. We claim that domain-general belief revision helps explain why we look for regularities in social life in the first place. We argue that it is the disposition to look for regularities and react to them that generates descriptive norms. In our search for rules, we create them
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