422 research outputs found
10061 Abstracts Collection -- Circuits, Logic, and Games
From 07/02/10 to 12/02/10, the Dagstuhl Seminar 10061 ``Circuits, Logic, and Games \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
Who’s at stake? The role of the stakeholder in UK tech policy
The idea of the ‘stakeholder’ is prevalent in discussions of technology policy. But who counts as a stakeholder, who holds power over who is included, whose voice is left out of technology policy discourses and practices?
The aim of this project is to gain a critical understanding of the definition and role of the ‘stakeholder’ in the development of technology policy. What counts as a ‘stake’? Who has a ‘stake’?
In this report, we present an analysis of 195 UK tech policy documents, assessed for the usage of the term stakeholder and citational practices. We also present results of a workshop with government, academia and civil society discussing policy practices, and provide recommendations for more representative processes for tech policy.Funded by a Solent University RIKE grant
Parallelizing Quantum Circuits
We present a novel automated technique for parallelizing quantum circuits via
forward and backward translation to measurement-based quantum computing
patterns and analyze the trade off in terms of depth and space complexity. As a
result we distinguish a class of polynomial depth circuits that can be
parallelized to logarithmic depth while adding only polynomial many auxiliary
qubits. In particular, we provide for the first time a full characterization of
patterns with flow of arbitrary depth, based on the notion of influencing paths
and a simple rewriting system on the angles of the measurement. Our method
leads to insightful knowledge for constructing parallel circuits and as
applications, we demonstrate several constant and logarithmic depth circuits.
Furthermore, we prove a logarithmic separation in terms of quantum depth
between the quantum circuit model and the measurement-based model.Comment: 34 pages, 14 figures; depth complexity, measurement-based quantum
computing and parallel computin
Reconsidering power and distance
A wide range of studies indicate that power and distance affect the production and interpretation of language. However, this paper argues that greater consideration needs to be given to the conceptual nature of these dimensions, and to terminological usage. In the first half of the paper, the need for this consideration is explained. A number of pragmatic studies are examined, and this reveals that authors often use the same terms with different meanings, or different terms with the same meaning, and that the parameters are rarely explicitly defined. Then the paper reviews recent calls for an extra parameter of interlocutor relations to be added: for affect to be separated from distance. In the second half of the paper, relevant social psychological research is reported, and it is concluded that the number of ‘horizontal’ dimensions of interlocutor relations needs to be reconsidered. Power, on the other hand, emerges as a robust and relatively unitary dimension, yet its label has connotations that may not be cross-culturally valid
Predicting Crop Yield With Machine Learning: An Extensive Analysis Of Input Modalities And Models On a Field and sub-field Level
We introduce a simple yet effective early fusion method for crop yield
prediction that handles multiple input modalities with different temporal and
spatial resolutions. We use high-resolution crop yield maps as ground truth
data to train crop and machine learning model agnostic methods at the sub-field
level. We use Sentinel-2 satellite imagery as the primary modality for input
data with other complementary modalities, including weather, soil, and DEM
data. The proposed method uses input modalities available with global coverage,
making the framework globally scalable. We explicitly highlight the importance
of input modalities for crop yield prediction and emphasize that the
best-performing combination of input modalities depends on region, crop, and
chosen model.Comment: 4 pages, 1 figure, 3 tables, IEEE IGARSS 202
The DEEP2 Galaxy Redshift Survey: Environments of Poststarburst Galaxies at z~0.1 and z~0.8
Postststarburst (K+A) galaxies are candidates for galaxies in transition from
a star-forming phase to a passively-evolving phase. We have spectroscopically
identified large samples of K+A galaxies both in the SDSS at z~0.1 and in the
DEEP2 survey at z~0.8, using a robust selection method based on a cut in Hbeta
emission rather than the more problematic [OII] 3727. Based on measurements of
the overdensity of galaxies around each object, we find that K+A galaxies
brighter than 0.4L*_B at low-z have a similar, statistically indistinguishable
environment distribution as blue galaxies, preferring underdense environments,
but dramatically different from that of red galaxies. However, at higher-z, the
environment distribution of K+A galaxies is more similar to red galaxies than
to blue galaxies. We conclude that the quenching of star formation and the
build-up of the red sequence through the K+A phase is happening in relatively
overdense environments at z~1 but in relatively underdense environments at z~0.
Although the relative environments where quenching occurs are decreasing with
time, the corresponding absolute environment may have stayed the same along
with the quenching mechanisms, because the mean absolute environments of all
galaxies has to grow with time. In addition, we do not find any significant
dependence on luminosity in the environment distribution of K+As. The existence
of a large K+A population in the field at both redshifts indicates that
cluster-specific mechanisms cannot be the dominant route by which these
galaxies are formed. We also demonstrates that studying K+A-environment
relations by measuring the K+A fraction in different environments is highly
non-robust. Statistical comparisons of the overall environment distributions of
different populations are much better behaved.Comment: 21 pages, 13 figures, 4 tables, submitted to MNRAS; v2: major
revision in Sec 5, 6, 7, and 9. Implemented robust statistical techniques in
place of K+A fraction measurements; conclusions on the environment
distribution of poststarbursts at z~0.8 have changed. Completely new
discussion added. v3: minor changes matching the accepted versio
Atmospheric abundance and global emissions of perfluorocarbons CF4, C2F6 and C3F8 since 1800 inferred from ice core, firn, air archive and in situ measurements
Perfluorocarbons (PFCs) are very potent and long-lived greenhouse gases in the atmosphere, released predominantly during aluminium production and semiconductor manufacture. They have been targeted for emission controls under the United Nations Framework Convention on Climate Change. Here we present the first continuous records of the atmospheric abundance of CF4 (PFC-14), C2F6 (PFC-116) and C3F8 (PFC-218) from 1800 to 2014. The records are derived from high-precision measurements of PFCs in air extracted from polar firn or ice at six sites (DE08, DE08-2, DSSW20K, EDML, NEEM and South Pole) and air archive tanks and atmospheric air sampled from both hemispheres. We take account of the age characteristics of the firn and ice core air samples and demonstrate excellent consistency between the ice core, firn and atmospheric measurements. We present an inversion for global emissions from 1900 to 2014. We also formulate the inversion to directly infer emission factors for PFC emissions due to aluminium production prior to the 1980s. We show that 19th century atmospheric levels, before significant anthropogenic influence, were stable at 34.1 ± 0.3 ppt for CF4 and below detection limits of 0.002 and 0.01 ppt for C2F6 and C3F8, respectively. We find a significant peak in CF4 and C2F6 emissions around 1940, most likely due to the high demand for aluminium during World War II, for example for construction of aircraft, but these emissions were nevertheless much lower than in recent years. The PFC emission factors for aluminium production in the early 20th century were significantly higher than today but have decreased since then due to improvements and better control of the smelting process. Mitigation efforts have led to decreases in emissions from peaks in 1980 (CF4) or early-to-mid-2000s (C2F6 and C3F8) despite the continued increase in global aluminium production; however, these decreases in emissions appear to have recently halted. We see a temporary reduction of around 15 % in CF4 emissions in 2009, presumably associated with the impact of the global financial crisis on aluminium and semiconductor production
Optimal estimation of the surface fluxes of methyl chloride using a 3-D global chemical transport model
Methyl chloride (CH3Cl) [CH subscript 3 Cl] is a chlorine-containing trace gas in the atmosphere contributing significantly to stratospheric ozone depletion. Large uncertainties in estimates of its source and sink magnitudes and temporal and spatial variations currently exist. GEIA inventories and other bottom-up emission estimates are used to construct a priori maps of the surface fluxes of CH3Cl [CH subscript 3 Cl]. The Model of Atmospheric Transport and Chemistry (MATCH), driven by NCEP interannually varying meteorological data, is then used to simulate CH3Cl [CH subscript 3 Cl] mole fractions and quantify the time series of sensitivities of the mole fractions at each measurement site to the surface fluxes of various regional and global sources and sinks. We then implement the Kalman filter (with the unit pulse response method) to estimate the surface fluxes on regional/global scales with monthly resolution from January 2000 to December 2004. High frequency observations from the AGAGE, SOGE, NIES, and NOAA/ESRL HATS in situ networks and low frequency observations from the NOAA/ESRL HATS flask network are used to constrain the source and sink magnitudes. The inversion results indicate global total emissions around 4100 ± 470 Gg yr−1 [yr superscript -1] with very large emissions of 2200 ± 390 Gg yr−1 [yr superscript -1] from tropical plants, which turn out to be the largest single source in the CH3Cl [CH subscript 3 Cl] budget. Relative to their a priori annual estimates, the inversion increases global annual fungal and tropical emissions, and reduces the global oceanic source. The inversion implies greater seasonal and interannual oscillations of the natural sources and sink of CH3Cl [CH subscript 3 Cl] compared to the a priori. The inversion also reflects the strong effects of the 2002/2003 globally widespread heat waves and droughts on global emissions from tropical plants, biomass burning and salt marshes, and on the soil sink.United States. National Aeronautics and Space Administration (Grant NNX07AE89G)United States. National Aeronautics and Space Administration (Grant NAG5-12669)United States. National Aeronautics and Space Administration (Grant NNX07AF09G)United States. National Aeronautics and Space Administration (Grant NNX07AE87G)National Science Foundation (U.S.) (Grant ATM-0120468)United States. National Aeronautics and Space Administration (Grant NAG5-12099
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