3,642 research outputs found
Crypto heater:a design fiction
This proposal is to exhibit the work named Crypto Heater which is part of a design fiction [c.f 1,5,8:30] series intended to explore a near future world in which cryptographic currencies such as Bitcoin [6] have become commonplace. This work opens up space for discussion about the activities of the distributed peer-to-peer network of so-called "miners" that ensure the security of the Bitcoin network and regulate the supply of new currency in the Bitcoin economy. The physical part of the work (the heater itself) is set within a fictional near-future reality. In this reality, Bitcoin has become central to our financial service industry, and "mining" in domestic settings is promoted by the government, as a means of heating our homes and to ensure security of the network. A "story world" is constructed using devices such as promotional materials from the UK Government's Ministry of Crypto Currency; technical specifications; customer testimonials; and the heater itself. The main element of the exhibit is a fully working Crypto Heater prototype. This device is (in the fictional world, and the real world) part of the distributed network of Bitcoin miners. Through computation, it converts electrical energy into cryptographic currency. Uniquely Crypto Heater dissipates the heat energy (a by-product of the computational effort required to be a Bitcoin miner) through a standard household radiator. By offsetting the value of the cryptographic currency produced, against the cost of electricity used, the heater provides subsidized domestic heating
Cosmology in a supersymmetric model with gauged
We consider salient cosmological features of a supersymmetric model which is
Left-Right symmetric and therefore possessing gauged symmetry. The
requirement of breaking parity and also obtaining charge preserving vacua
introduces some unique features to this model (MSLRM), resulting in a
preference for non-thermal Leptogenesis. Assuming that the model preserves TeV
scale supersymmetry, we show that the vacuum structure generically possesses
domain walls, which can serve two important purposes. They can signal a
secondary inflation required to remove unwanted relics such as gravitino and
moduli and also generate lepton asymmetry by a mechanism similar to electroweak
baryogenesis. The requirement of disappearance of domain walls imposes
constraints on the soft parameters of the theory, testable at the TeV scale. We
also propose an alternative model with spontaneous parity violation
(MSLR\rlap/P). Incorporating the same cosmological considerations in this case
entails constraints on a different set of soft parameters.Comment: 18 pages. Minor changes in text, but conclusion remains same.
Published in Phys. Rev.
A process activity monitor for AOS/VS
With the ever increasing concern for computer security, users of computer systems are becoming more sensitive to unauthorized access. One of the initial security concerns for the Shuttle Management Information System was the problem of users leaving their workstations unattended while still connected to the system. This common habit was a concern for two reasons: it ties up resources unnecessarily and it opens the way for unauthorized access to the system. The Data General MV/10000 does not come equipped with an automatic time-out option on interactive peripherals. The purpose of this memorandum is to describe a system which monitors process activity on the system and disconnects those users who show no activity for some time quantum
Harold Jeffreys's Theory of Probability Revisited
Published exactly seventy years ago, Jeffreys's Theory of Probability (1939)
has had a unique impact on the Bayesian community and is now considered to be
one of the main classics in Bayesian Statistics as well as the initiator of the
objective Bayes school. In particular, its advances on the derivation of
noninformative priors as well as on the scaling of Bayes factors have had a
lasting impact on the field. However, the book reflects the characteristics of
the time, especially in terms of mathematical rigor. In this paper we point out
the fundamental aspects of this reference work, especially the thorough
coverage of testing problems and the construction of both estimation and
testing noninformative priors based on functional divergences. Our major aim
here is to help modern readers in navigating in this difficult text and in
concentrating on passages that are still relevant today.Comment: This paper commented in: [arXiv:1001.2967], [arXiv:1001.2968],
[arXiv:1001.2970], [arXiv:1001.2975], [arXiv:1001.2985], [arXiv:1001.3073].
Rejoinder in [arXiv:0909.1008]. Published in at
http://dx.doi.org/10.1214/09-STS284 the Statistical Science
(http://www.imstat.org/sts/) by the Institute of Mathematical Statistics
(http://www.imstat.org
Urban particulate pollution reduction by four species of green roof vegetation in a UK city
AbstractUrban particulate pollution in the UK remains at levels which have the potential to cause negative impacts on human health. There is a need, therefore, for mitigation strategies within cities, especially with regards to vehicular sources. The use of vegetation as a passive filter of urban air has been previously investigated, however green roof vegetation has not been specifically considered. The present study aims to quantify the effectiveness of four green roof species – creeping bentgrass (Agrostis stolonifera), red fescue (Festuca rubra), ribwort plantain (Plantago lanceolata) and sedum (Sedum album) – at capturing particulate matter smaller than 10 μm (PM10). Plants were grown in a location away from major road sources of PM10 and transplanted onto two roofs in Manchester city centre. One roof is adjacent to a major traffic source and one roof is characterised more by urban background inputs. Significant differences in metal containing PM10 capture were found between sites and between species. Site differences were explained by proximity to major sources. Species differences arise from differences in macro and micro morphology of the above surface biomass. The study finds that the grasses, A. stolonifera and F. rubra, are more effective than P. lanceolata and S. album at PM10 capture. Quantification of the annual PM10 removal potential was calculated under a maximum sedum green roof installation scenario for an area of the city centre, which totals 325 ha. Remediation of 2.3% (±0.1%) of 9.18 tonnes PM10 inputs for this area could be achieved under this scenario
Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy
The analysis of gravitational wave data involves many model selection
problems. The most important example is the detection problem of selecting
between the data being consistent with instrument noise alone, or instrument
noise and a gravitational wave signal. The analysis of data from ground based
gravitational wave detectors is mostly conducted using classical statistics,
and methods such as the Neyman-Pearson criteria are used for model selection.
Future space based detectors, such as the \emph{Laser Interferometer Space
Antenna} (LISA), are expected to produced rich data streams containing the
signals from many millions of sources. Determining the number of sources that
are resolvable, and the most appropriate description of each source poses a
challenging model selection problem that may best be addressed in a Bayesian
framework. An important class of LISA sources are the millions of low-mass
binary systems within our own galaxy, tens of thousands of which will be
detectable. Not only are the number of sources unknown, but so are the number
of parameters required to model the waveforms. For example, a significant
subset of the resolvable galactic binaries will exhibit orbital frequency
evolution, while a smaller number will have measurable eccentricity. In the
Bayesian approach to model selection one needs to compute the Bayes factor
between competing models. Here we explore various methods for computing Bayes
factors in the context of determining which galactic binaries have measurable
frequency evolution. The methods explored include a Reverse Jump Markov Chain
Monte Carlo (RJMCMC) algorithm, Savage-Dickie density ratios, the Schwarz-Bayes
Information Criterion (BIC), and the Laplace approximation to the model
evidence. We find good agreement between all of the approaches.Comment: 11 pages, 6 figure
OT 060420: A Seemingly Optical Transient Recorded by All-Sky Cameras
We report on a ~5th magnitude flash detected for approximately 10 minutes by
two CONCAM all-sky cameras located in Cerro Pachon - Chile and La Palma -
Spain. A third all-sky camera, located in Cerro Paranal - Chile did not detect
the flash, and therefore the authors of this paper suggest that the flash was a
series of cosmic-ray hits, meteors, or satellite glints. Another proposed
hypothesis is that the flash was an astronomical transient with variable
luminosity. In this paper we discuss bright optical transient detection using
fish-eye all-sky monitors, analyze the apparently false-positive optical
transient, and propose possible causes to false optical transient detection in
all-sky cameras.Comment: 7 figures, 3 tables, accepted PAS
Making AI-Infused Products and Services More Legible
The increasing availability of large data sets has initiated a resurgence in artificial intelligence (AI) research. Today AI is integrated into a wide variety of so-called smart products to personalize user experiences. Smart technologies are typically designed for ease of use, with their complex underlying procedures (intentionally) obfuscated; explaining particular outcomes is hampered by their inherent ambiguity. This lack of legibility leads to misconceptions about how AI works. Through design research, the authors address the challenge of AI legibility by designing AI iconography as an accessible way to communicate and better understand the role AI and data increasingly play in our everyday interactions
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