651 research outputs found
HFR Code: A Flexible Replication Scheme for Cloud Storage Systems
Fractional repetition (FR) codes are a family of repair-efficient storage
codes that provide exact and uncoded node repair at the minimum bandwidth
regenerating point. The advantageous repair properties are achieved by a
tailor-made two-layer encoding scheme which concatenates an outer
maximum-distance-separable (MDS) code and an inner repetition code. In this
paper, we generalize the application of FR codes and propose heterogeneous
fractional repetition (HFR) code, which is adaptable to the scenario where the
repetition degrees of coded packets are different. We provide explicit code
constructions by utilizing group divisible designs, which allow the design of
HFR codes over a large range of parameters. The constructed codes achieve the
system storage capacity under random access repair and have multiple repair
alternatives for node failures. Further, we take advantage of the systematic
feature of MDS codes and present a novel design framework of HFR codes, in
which storage nodes can be wisely partitioned into clusters such that data
reconstruction time can be reduced when contacting nodes in the same cluster.Comment: Accepted for publication in IET Communications, Jul. 201
Microsofts Monopoly: Anti-Competitive Behavior, Predatory Tactics, And The Failure Of Governmental Will
Thirty years ago, Microsoft Corp. was founded by Bill Gates and Paul Allen. To understand how the company has gained competitive advantage we examine how the company used unfair, anti-competitive, and predatory approaches in their business. We discuss how we have come to the belief that the government settlement in United States and State of New York, et al., v. Microsoft Corporation imposing restrictions on Microsoft’s behavior and monitoring its actions for compliance is not enough to keep it from abusing its monopolistic power and does too little to prevent it from dominating the software and operating system industry today
The Jock Tax Contest: Professional Athletes Vs. The States - Background And Current Developments
Opening day of the Major League Baseball?s 2002 season fell on April 1 of that year. After the National Anthem was sung, the crowd applauded as the New York Mets took the field, and the umpire yelled, “play ball.” The State of New York also cheered. Why? New York, like a number of other states and localities, imposes an income tax on athletes that visit its borders. So, when Tex- as Rangers shortstop, Alex Rodriguez, the highest paid baseball player during the 2002 season with a salary of 34,250. This state income taxation of nonresident professional athletes is commonly referred to as “the jock tax.” This paper introduces the reader to the jock tax beginning with a brief explanation of state income taxes, continuing with a discussion of its complexi- ties and historical/current issues faced by athletes, teams and the states through implementation of the tax. The paper concludes with the broader implications of a state or local taxing jurisdiction's powers to tax its nonresident visitors.
The Detection of Ionizing Radiation by Plasma Panel Sensors: Cosmic Muons, Ion Beams and Cancer Therapy
The plasma panel sensor is an ionizing photon and particle radiation detector
derived from PDP technology with high gain and nanosecond response.
Experimental results in detecting cosmic ray muons and beta particles from
radioactive sources are described along with applications including high energy
and nuclear physics, homeland security and cancer therapeuticsComment: Presented at SID Symposium, June 201
Dielectric properties of hydrogen-incorporated chemical vapor deposited diamond thin films
Diamond thin films with a broad range of microstructures from a ultrananocrystalline diamond (UNCD) form developed at Argonne National Laboratory to a microcrystalline diamond (MCD) form have been grown with different hydrogen percentages in the Ar/CH4 gas mixture used in the microwave plasma enhanced chemical vapor deposition (CVD) process. The dielectric properties of the CVD diamond thin films have been studied using impedance and dc measurements on metal-diamond-metal test structures. Close correlations have been observed between the hydrogen content in the bulk of the diamond films, measured by elastic recoil detection (ERD), and their electrical conductivity and capacitance-frequency (C-f) behaviors. Addition of hydrogen gas in the Ar/CH4 gas mixture used to grow the diamond films appears to have two main effects depending on the film microstructure, namely, (a) in the UNCD films, hydrogen incorporates into the atomically abrupt grain boundaries satisfying sp2 carbon dangling bonds, resulting in increased resistivity, and (b) in MCD, atomic hydrogen produced in the plasma etches preferentially the graphitic phase codepositing with the diamond phase, resulting in the statistical survival and growth of large diamond grains and dominance of the diamond phase, and thus having significant impact on the dielectric properties of these films
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TIPS AND TRAPS: METHODOLOGICAL ISSUES RELATED TO CONDUCTING AN ONLINE TRIP PLANNING STUD
This study examines methodological issues related to studying American college students’ online travel planning behavior. A mixed method approach, which integrated think-aloud protocol combined with the process tracing method, log analysis and survey techniques, was evaluated in this paper. In previous studies, this methodological approach has been subject to issues of reliability and validity that were addressed in the design of the current study. Specifically, questions were related to whether the experiment used in this study would yield results comparable to the decision-making and search processes respondents would engage upon on their real-life trip planning. The purpose of this paper was to discuss how this study has evolved from previous work in this area in order to increase reliability and validity. Issues regarding the artificiality of the environment are addressed in this paper. Overall it was found that the qualitative- based, mixed-method approach used in this study was deemed appropriate and has resulted in delivering insights into the phenomena of online travel planning
Plasma Panel Sensors for Particle and Beam Detection
The plasma panel sensor (PPS) is an inherently digital, high gain, novel
variant of micropattern gas detectors inspired by many operational and
fabrication principles common to plasma display panels (PDPs). The PPS is
comprised of a dense array of small, plasma discharge, gas cells within a
hermetically-sealed glass panel, and is assembled from non-reactive,
intrinsically radiation-hard materials such as glass substrates, metal
electrodes and mostly inert gas mixtures. We are developing the technology to
fabricate these devices with very low mass and small thickness, using gas gaps
of at least a few hundred micrometers. Our tests with these devices demonstrate
a spatial resolution of about 1 mm. We intend to make PPS devices with much
smaller cells and the potential for much finer position resolutions. Our PPS
tests also show response times of several nanoseconds. We report here our
results in detecting betas, cosmic-ray muons, and our first proton beam tests.Comment: 2012 IEEE NS
Development of a plasma panel radiation detector: recent progress and key issues
A radiation detector based on plasma display panel technology, which is the
principal component of plasma television displays is presented. Plasma Panel
Sensor (PPS) technology is a variant of micropattern gas radiation detectors.
The PPS is conceived as an array of sealed plasma discharge gas cells which can
be used for fast response (O(5ns) per pixel), high spatial resolution detection
(pixel pitch can be less than 100 micrometer) of ionizing and minimum ionizing
particles. The PPS is assembled from non-reactive, intrinsically radiation-hard
materials: glass substrates, metal electrodes and inert gas mixtures. We report
on the PPS development program, including simulations and design and the first
laboratory studies which demonstrate the usage of plasma display panels in
measurements of cosmic ray muons, as well as the expansion of experimental
results on the detection of betas from radioactive sources.Comment: presented at IEEE NSS 2011 (Barcelona
Antiferromagnetic order in CaK(Fe[1-x]Ni[x])4As4 and its interplay with superconductivity
The magnetic order in CaK(Fe[1-x]Ni[x])4As4 (1144) single crystals (x = 0.051
and 0.033) has been studied by neutron diffraction. We observe magnetic Bragg
peaks associated to the same propagation vectors as found for the collinear
stripe antiferromagnetic (AFM) order in the related BaFe2As2 (122) compound.
The AFM state in 1144 preserves tetragonal symmetry and only a commensurate,
non-collinear structure with a hedgehog spin-vortex crystal (SVC) arrangement
in the Fe plane and simple AFM stacking along the c direction is consistent
with our observations. The SVC order is promoted by the reduced symmetry in the
FeAs layer in the 1144 structure. The long-range SVC order coexists with
superconductivity, however, similar to the doped 122 compounds, the ordered
magnetic moment is gradually suppressed with the developing superconducting
order parameter. This supports the notion that both collinear and non-collinear
magnetism and superconductivity are competing for the same electrons coupled by
Fermi surface nesting in iron arsenide superconductors.Comment: (5 pages, 5 figures
Computational, Integrative, and Comparative Methods for the Elucidation of Genetic Coexpression Networks
Gene expression microarray data can be used for the assembly of genetic coexpression network graphs. Using mRNA samples obtained from recombinant inbred Mus musculus strains, it is possible to integrate allelic variation with molecular and higher-order phenotypes. The depth of quantitative genetic analysis of microarray data can be vastly enhanced utilizing this mouse resource in combination with powerful computational algorithms, platforms, and data repositories. The resulting network graphs transect many levels of biological scale. This approach is illustrated with the extraction of cliques of putatively coregulated genes and their annotation using gene ontology analysis and cis-regulatory element discovery. The causal basis for coregulation is detected through the use of quantitative trait locus mapping
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