158,015 research outputs found

    Confrontation and the Unavailable Witness: Searching for a Standard

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    Lower Bounds for Structuring Unreliable Radio Networks

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    In this paper, we study lower bounds for randomized solutions to the maximal independent set (MIS) and connected dominating set (CDS) problems in the dual graph model of radio networks---a generalization of the standard graph-based model that now includes unreliable links controlled by an adversary. We begin by proving that a natural geographic constraint on the network topology is required to solve these problems efficiently (i.e., in time polylogarthmic in the network size). We then prove the importance of the assumption that nodes are provided advance knowledge of their reliable neighbors (i.e, neighbors connected by reliable links). Combined, these results answer an open question by proving that the efficient MIS and CDS algorithms from [Censor-Hillel, PODC 2011] are optimal with respect to their dual graph model assumptions. They also provide insight into what properties of an unreliable network enable efficient local computation.Comment: An extended abstract of this work appears in the 2014 proceedings of the International Symposium on Distributed Computing (DISC

    A distributed programming environment for Ada

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    Despite considerable commercial exploitation of fault tolerance systems, significant and difficult research problems remain in such areas as fault detection and correction. A research project is described which constructs a distributed computing test bed for loosely coupled computers. The project is constructing a tool kit to support research into distributed control algorithms, including a distributed Ada compiler, distributed debugger, test harnesses, and environment monitors. The Ada compiler is being written in Ada and will implement distributed computing at the subsystem level. The design goal is to provide a variety of control mechanics for distributed programming while retaining total transparency at the code level

    Point Cloud Framework for Rendering 3D Models Using Google Tango

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    This project seeks to demonstrate the feasibility of point cloud meshing for capturing and modeling three dimensional objects on consumer smart phones and tablets. Traditional methods of capturing objects require hundreds of images, are very slow and consume a large amount of cellular data for the average consumer. Software developers need a starting point for capturing and meshing point clouds to create 3D models as hardware manufacturers provide the tools to capture point cloud data. The project uses Googles Tango computer vision library for Android to capture point clouds on devices with depth-sensing hardware. The point clouds are combined and meshed as models for use in 3D rendering projects. We expect our results to be embraced by the Android market because capturing point clouds is fast and does not carry a large data footprint

    Model for cryptography protection of confidential information

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    УДК 004.056 Борсуковський Ю.В., Борсуковська В.Ю. Модель криптографічного захисту конфіденційної інформації В даній статті проведено детальний аналіз вимог щодо формування моделі криптографічного захисту конфіденційної інформації. Розглянуто використання засобів криптографічного захисту інформації з метою реалізації організаційних та технічних заходів по запобіганню витокам конфіденційної інформації на об’єктах критичної інфраструктури. Сформульовані базові вимоги та рекомендації щодо структури та функціональних складових моделі захисту конфіденційної інформації. Формалізовані вимоги щодо створення, впровадження та експлуатації превентивних процедур управління багатоступінчатим захистом конфіденційної інформації. Наведено приклад використання моделі криптографічного захисту інформації для створення захищеної і прозорої в використанні бази аутентифікаційних даних користувача. Запропонована модель захисту дозволяє мати кілька ступенів програмного та апаратного захисту, що із однієї сторони спрощує їх використання при виконанні чинних політик безпеки і зменшує ймовірність дискредитації аутентифікаційних даних, а із іншої сторони підвищує ймовірність виявлення зловмисних дій третьої сторони за рахунок багатоступінчатої системи захисту. Враховано практичний досвід створення типових моделей захисту конфіденційної інформації для розробки, впровадження та управління сучасними політиками інформаційної безпеки щодо питань використання засобів криптографічного захисту конфіденційної інформації на підприємствах різних форми власності.UDC 004.056 Borsukovskyi Y., Borsukovska V. Model for Cryptography Protection of Confidential Information Current article provides the detailed analysis of requirements for creation of model for cryptography protection of confidential information. Article defines the use of information cryptography protection tools in order to ensure the application of organizational and technical actions to prevent leakage of confidential information at critical infrastructure assets. It provides the basic requirements for the structure and functional elements of model for protection of confidential information. Formalize requirements on creation, implementation and exploitation of preventive procedure in management of multi-level protection of confidential information. The article includes example of use of model for cryptography protection of information for creation of secure and transparent in use the authenticating data base of user. The presented model of protection ensures to have a few levels of firewalls, that, on one hand, simplifies its use in execution of acting security policies and decrease the probability of discrediting of authenticating data, and, on other hand, increase the probability to detect the criminal actions of third party by means of multi-level protection system. It considers the practical experience in creation of standard models for protection of confidential information for development, implementation and management of modern policies on information security in part of use of cryptography protection tools for confidential information at enterprises of different forms of incorporation

    Assessment of First-Principles and Semiempirical Methodologies for Absorption and Emission Energies of Ce3+^{3+}-Doped Luminescent Materials

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    In search of a reliable methodology for the prediction of light absorption and emission of Ce3+^{3+}-doped luminescent materials, 13 representative materials are studied with first-principles and semiempirical approaches. In the first-principles approach, that combines constrained density-functional theory and Δ\DeltaSCF, the atomic positions are obtained for both ground and excited states of the Ce3+^{3+} ion. The structural information is fed into Dorenbos' semiempirical model. Absorption and emission energies are calculated with both methods and compared with experiment. The first-principles approach matches experiment within 0.3 eV, with two exceptions at 0.5 eV. In contrast, the semiempirical approach does not perform as well (usually more than 0.5 eV error). The general applicability of the present first-principles scheme, with an encouraging predictive power, opens a novel avenue for crystal site engineering and high-throughput search for new phosphors and scintillators.Comment: 12 pages, 3 figure

    The role of title insurance under recording and registration

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    This article outlines a transaction cost theory of ‘title insurance’ and analyses the role it plays in countries with recording and registration of land titles. Title insurance indemnifies real estate right holders for losses caused by pre-existing title defects that are unknown when the policy is issued. It emerged to complement the ‘errors and omissions’ insurance of professionals examining title quality. Poor organization of public records led title insurers in the USA to integrate title examination and settlement services. Their residual claimant status motivates insurers to screen, cure and avoid title defects. Firms introducing title insurance abroad produce little information on title quality, however. Their policies are instead issued on a casualty basis, complementing and enforcing the professional liability of conveyancers. Future development in markets with land registration is uncertain because of adverse selection, competitive reactions from established conveyancers and the ability of larger banks to self-insure title risks.Transaction costs, property rights, land titles, title insurance, real estate
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