192,197 research outputs found
Moving Multimedia Simulations into the Cloud: a Cost-Effective Solution
Researchers often demand bursts of computing power to quickly obtain the results of certain simulation activities. Multimedia communication simulations usually belong to such category. They may require several days on a generic PC to test a comprehensive set of conditions depending on the complexity of the scenario. This paper proposes to use a cloud computing framework to accelerate these simulations and, consequently, research activities, while at the same time reducing the overall costs. A practical simulation example is shown, representative of a typical simulation of H.264/AVC video communications over a wireless channel. This work shows that, by means of a commercial cloud computing provider, the gains of the proposed technique compared to more traditional solutions using dedicated computers can be significant in terms of speed and cost reductio
A quantum computer only needs one universe
The nature of quantum computation is discussed. It is argued that, in terms
of the amount of information manipulated in a given time, quantum and classical
computation are equally efficient. Quantum superposition does not permit
quantum computers to ``perform many computations simultaneously'' except in a
highly qualified and to some extent misleading sense. Quantum computation is
therefore not well described by interpretations of quantum mechanics which
invoke the concept of vast numbers of parallel universes. Rather, entanglement
makes available types of computation process which, while not exponentially
larger than classical ones, are unavailable to classical systems. The essence
of quantum computation is that it uses entanglement to generate and manipulate
a physical representation of the correlations between logical entities, without
the need to completely represent the logical entities themselves.Comment: 13 pages. The paper has undergone major changes, in order to
stengthen the argument and cut extraneous material. Schrodinger's Cat has
been cut. The "one-way computer" model is now included, and the other remarks
tightened. A positive statement on what a QC is, as opposed to what it is
not, is adde
Optimized Surface Code Communication in Superconducting Quantum Computers
Quantum computing (QC) is at the cusp of a revolution. Machines with 100
quantum bits (qubits) are anticipated to be operational by 2020
[googlemachine,gambetta2015building], and several-hundred-qubit machines are
around the corner. Machines of this scale have the capacity to demonstrate
quantum supremacy, the tipping point where QC is faster than the fastest
classical alternative for a particular problem. Because error correction
techniques will be central to QC and will be the most expensive component of
quantum computation, choosing the lowest-overhead error correction scheme is
critical to overall QC success. This paper evaluates two established quantum
error correction codes---planar and double-defect surface codes---using a set
of compilation, scheduling and network simulation tools. In considering
scalable methods for optimizing both codes, we do so in the context of a full
microarchitectural and compiler analysis. Contrary to previous predictions, we
find that the simpler planar codes are sometimes more favorable for
implementation on superconducting quantum computers, especially under
conditions of high communication congestion.Comment: 14 pages, 9 figures, The 50th Annual IEEE/ACM International Symposium
on Microarchitectur
Large-scale Reservoir Simulations on IBM Blue Gene/Q
This paper presents our work on simulation of large-scale reservoir models on
IBM Blue Gene/Q and studying the scalability of our parallel reservoir
simulators. An in-house black oil simulator has been implemented. It uses MPI
for communication and is capable of simulating reservoir models with hundreds
of millions of grid cells. Benchmarks show that our parallel simulator are
thousands of times faster than sequential simulators that designed for
workstations and personal computers, and the simulator has excellent
scalability
Longitudinal study of low and high achievers in early mathematics
Background. Longitudinal studies allow us to identify, which specific maths skills are
weak in young children, and whether there is a continuing weakness in these areas
throughout their school years.
Aims. This 2-year study investigated whether certain socio-demographic variables
affect early mathematical competency in children aged 5–7 years.
Sample. A randomly selected sample of 127 students (64 female; 63 male) participated.
At the start of the study, the students were approximately 5 years old (M = 5.2;
SD = 0.28; range = 4.5–5.8).
Method. The students were assessed using the Early Numeracy Test and then
allocated to a high (n = 26), middle (n = 76), or low (n = 25) achievers group.
The same children were assessed again with the Early Numeracy Test at 6 and 7 years
old, respectively. Eight socio-demographic characteristics were also evaluated: family
model, education of the parent(s), job of the parent(s), number of family members,
birth order, number of computers at home, frequency of teacher visits, and hours
watching television.
Results. Early Numeracy Test scores were more consistent for the high-achievers
group than for the low-achievers group. Approximately 5.5% of low achievers obtained
low scores throughout the study. A link between specific socio-demographic characteristics
and early achievement in mathematics was only found for number of computers
at home.
Conclusions. The level of mathematical ability among students aged 5–7 years
remains relatively stable regardless of the initial level of achievement. However, early
screening for mathematics learning disabilities could be useful in helping low-achieving
students overcome learning obstacles.This material is based on work supported by the Spanish Ministry of Science & Technology grant no. SEJ2007-62420/EDUC and Junta de Andalucia grant no. P09-HUM-4918
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