25,431 research outputs found
Von Neumann Normalisation of a Quantum Random Number Generator
In this paper we study von Neumann un-biasing normalisation for ideal and
real quantum random number generators, operating on finite strings or infinite
bit sequences. In the ideal cases one can obtain the desired un-biasing. This
relies critically on the independence of the source, a notion we rigorously
define for our model. In real cases, affected by imperfections in measurement
and hardware, one cannot achieve a true un-biasing, but, if the bias "drifts
sufficiently slowly", the result can be arbitrarily close to un-biasing. For
infinite sequences, normalisation can both increase or decrease the
(algorithmic) randomness of the generated sequences. A successful application
of von Neumann normalisation---in fact, any un-biasing transformation---does
exactly what it promises, un-biasing, one (among infinitely many) symptoms of
randomness; it will not produce "true" randomness.Comment: 27 pages, 2 figures. Updated to published versio
Gaze-based teleprosthetic enables intuitive continuous control of complex robot arm use: Writing & drawing
Eye tracking is a powerful mean for assistive technologies for people with movement disorders, paralysis and amputees. We present a highly intuitive eye tracking-controlled robot arm operating in 3-dimensional space based on the user's gaze target point that enables tele-writing and drawing. The usability and intuitive usage was assessed by a “tele” writing experiment with 8 subjects that learned to operate the system within minutes of first time use. These subjects were naive to the system and the task and had to write three letters on a white board with a white board pen attached to the robot arm's endpoint. The instructions are to imagine they were writing text with the pen and look where the pen would be going, they had to write the letters as fast and as accurate as possible, given a letter size template. Subjects were able to perform the task with facility and accuracy, and movements of the arm did not interfere with subjects ability to control their visual attention so as to enable smooth writing. On the basis of five consecutive trials there was a significant decrease in the total time used and the total number of commands sent to move the robot arm from the first to the second trial but no further improvement thereafter, suggesting that within writing 6 letters subjects had mastered the ability to control the system. Our work demonstrates that eye tracking is a powerful means to control robot arms in closed-loop and real-time, outperforming other invasive and non-invasive approaches to Brain-Machine-Interfaces in terms of calibration time (<;2 minutes), training time (<;10 minutes), interface technology costs. We suggests that gaze-based decoding of action intention may well become one of the most efficient ways to interface with robotic actuators - i.e. Brain-Robot-Interfaces - and become useful beyond paralysed and amputee users also for the general teleoperation of robotic and exoskeleton in human augmentation
Guidance, flight mechanics and trajectory optimization. Volume 2 - Observation theory and sensors
Observation theory and sensors applicable to navigation of boost and space vehicle
A Non-Probabilistic Model of Relativised Predictability in Physics
Little effort has been devoted to studying generalised notions or models of
(un)predictability, yet is an important concept throughout physics and plays a
central role in quantum information theory, where key results rely on the
supposed inherent unpredictability of measurement outcomes. In this paper we
continue the programme started in [1] developing a general, non-probabilistic
model of (un)predictability in physics. We present a more refined model that is
capable of studying different degrees of "relativised" unpredictability. This
model is based on the ability for an agent, acting via uniform, effective
means, to predict correctly and reproducibly the outcome of an experiment using
finite information extracted from the environment. We use this model to study
further the degree of unpredictability certified by different quantum
phenomena, showing that quantum complementarity guarantees a form of
relativised unpredictability that is weaker than that guaranteed by
Kochen-Specker-type value indefiniteness. We exemplify further the difference
between certification by complementarity and value indefiniteness by showing
that, unlike value indefiniteness, complementarity is compatible with the
production of computable sequences of bits.Comment: 10 page
Guidance, flight mechanics and trajectory optimization. Volume 10 - Dynamic programming
Dynamic programming and multistage decision processes in guidance, flight mechanics, and trajectory optimizatio
Measuring impact of academic research in computer and information science on society
Academic research in computer & information science (CIS) has
contributed immensely to all aspects of society. As academic
research today is substantially supported by various government
sources, recent political changes have created ambivalence
amongst academics about the future of research funding. With
uncertainty looming, it is important to develop a framework to
extract and measure the information relating to impact of CIS
research on society to justify public funding, and demonstrate the
actual contribution and impact of CIS research outside academia.
A new method combining discourse analysis and text mining of a
collection of over 1000 pages of impact case study documents
written in free-text format for the Research Excellence
Framework (REF) 2014 was developed in order to identify the
most commonly used categories or headings for reporting impact
of CIS research by UK Universities (UKU). According to the
research reported in REF2014, UKU acquired 83 patents in
various areas of CIS, created 64 spin-offs, generated £857.5
million in different financial forms, created substantial
employment, reached over 6 billion users worldwide and has
helped save over £1 billion Pounds due to improved processes etc.
to various sectors internationally, between 2008 and 2013
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Effect of side chains on the dielectric properties of alkyl esters derived from palm kernel oil
Alkyl ester derivatives were synthesized from laboratory purified palm kernel oil. The steps in the synthesis involved transesterification of palm kernel oil to produce a methyl ester, followed by epoxidation and then the grafting of side chains by esterification with propionic and butyric anhydride. The dielectric and thermal properties of the ester derivatives were analyzed and compared with the methyl ester. The melting point of the ester derivatives were found to reduce with side chain attachment and antioxidant improved its thermal stability. The dielectric loss was dominated by mobile charged particles and the chemical modification appeared to increase the rate at which electric double layer was formed at the electrode-liquid interface. The esters possessed excellent breakdown strengths suggesting that the processing to optimize their physical properties did not have a negative influence on their electrical breakdown strength. This product may prove useful as an insulation fluid in Electrical Power Transformers
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