2,596 research outputs found
Planning assistance for the 30/20 GHz program, volume 3
The three basic experiment categories and consolidated experiments proposed by members of the Carrier Working Group are defined by category and by carrier. The three experiment categories are: (1) Possible Service (PS); (2) Possible Service and Technology (PSAT); and (3) Possible Technology (PT). Under Task 9 Western Union provided review, recommendations and critique of the NASA generated Statement of Work (SOW) defining the technical requirements governing design, launch and operation of the 30/20 GHz experimental systems
Planning assistance for the 30/20 GHz program, volume 1
Functional requirements for the 30/20 GHz communication system, planning assistance for the 30/20 GHz program, and a review of specified conceptual designs and recommendations are provided
Experimental demonstration of a graph state quantum error-correction code
Scalable quantum computing and communication requires the protection of
quantum information from the detrimental effects of decoherence and noise.
Previous work tackling this problem has relied on the original circuit model
for quantum computing. However, recently a family of entangled resources known
as graph states has emerged as a versatile alternative for protecting quantum
information. Depending on the graph's structure, errors can be detected and
corrected in an efficient way using measurement-based techniques. In this
article we report an experimental demonstration of error correction using a
graph state code. We have used an all-optical setup to encode quantum
information into photons representing a four-qubit graph state. We are able to
reliably detect errors and correct against qubit loss. The graph we have
realized is setup independent, thus it could be employed in other physical
settings. Our results show that graph state codes are a promising approach for
achieving scalable quantum information processing
Thermal Studies on Rubidium Dinitramide
The present study has been carried out to investigate conflicting reports in the literature on the nature of the thermal decomposition of the energetic oxidant rubidium dinitramide in the liquid state. The techniques employed included DSC, simultaneous TG-DTA, simultaneous TG-mass spectrometry and thermomicroscopy. The measurements were supplemented by quantitative chemical analysis of the reaction products. The results showed that, following fusion at 106 °C, the overall decomposition proceeded in a single exothermic reaction stage forming a mixture of rubidium nitrate and rubidium nitrite in the molar ratio 1.2 : 1
Survival of entanglement in thermal states
We present a general sufficiency condition for the presence of multipartite
entanglement in thermal states stemming from the ground state entanglement. The
condition is written in terms of the ground state entanglement and the
partition function and it gives transition temperatures below which
entanglement is guaranteed to survive. It is flexible and can be easily adapted
to consider entanglement for different splittings, as well as be weakened to
allow easier calculations by approximations. Examples where the condition is
calculated are given. These examples allow us to characterize a minimum gapping
behavior for the survival of entanglement in the thermodynamic limit. Further,
the same technique can be used to find noise thresholds in the generation of
useful resource states for one-way quantum computing.Comment: 6 pages, 2 figures. Changes made in line with publication
recommendations. Motivation and concequences of result clarified, with the
addition of one more example, which applies the result to give noise
thresholds for measurement based quantum computing. New author added with new
result
The self-assembly of DNA Holliday junctions studied with a minimal model
In this paper, we explore the feasibility of using coarse-grained models to
simulate the self-assembly of DNA nanostructures. We introduce a simple model
of DNA where each nucleotide is represented by two interaction sites
corresponding to the phosphate-sugar backbone and the base. Using this model,
we are able to simulate the self-assembly of both DNA duplexes and Holliday
junctions from single-stranded DNA. We find that assembly is most successful in
the temperature window below the melting temperatures of the target structure
and above the melting temperature of misbonded aggregates. Furthermore, in the
case of the Holliday junction, we show how a hierarchical assembly mechanism
reduces the possibility of becoming trapped in misbonded configurations. The
model is also able to reproduce the relative melting temperatures of different
structures accurately, and allows strand displacement to occur.Comment: 13 pages, 14 figure
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An Artificial Neural Network Approach to Learning from Factory Performance in a Kanban-Based System
Many Just-In-Time (JIT) manufacturing environments generate operational data reflecting both efficient and inefficient factory performance. Frequently data for inefficient performance is lost or discarded for fear of replicating poor performance. The purpose of this paper is two fold. First, historical JIT shop data is analyzed using a genetic algorithm (GA) to determine which shop factors are important determinants offactory performance. Second, subsequent to these important factors being identified by a GA, an artificial neural network (ANN) is used to learn the relationships between these factors and factory performance. The ANN can then be used to predict factory performance for future shop conditions and enhance shop performance. While ANN learning techniques have previously been applied to JIT production systems (Wray, Rakes, and Rees, 1997) (Markham, Mathieu, and Wray, 2000), these techniques have only been trained on data sets that reflect an efficient factory. Mathieu, Wray, and Markham (2002) investigated inefficient and efficient JIT factory performance but did not deploy either ANNs or a GA. In this paper an example application is presented using a GA to specify important shop factors and to predict saturated, starved or efficient factory performance based on dynamic shop floor data
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