755 research outputs found
Software Look and Feel Protection in the 1990s
This article reviews the historical development of look and feel copyright protection of computer software, including discussion of decisions favoring broad protection, decisions favoring competitive principles, and decisions taking an analytic approach to software copyright protection. The article also analyzes recent U.S. Supreme Court decisions to explore how the Court may decide the computer software look and feel issues, including consideration of how Lanham Act trade dress protection might be applied to protect computer software visual displays
Gauge-string duality for (non)supersymmetric deformations of N=4 Super Yang-Mills theory
We consider a non-supersymmetric example of the AdS/CFT duality which
generalizes the supersymmetric exactly marginal deformation constructed in
hep-th/0502086. The string theory background we use was found in hep-th/0503201
from the AdS_5 x S5 by a combination of T-dualities and shifts of angular
coordinates. It depends on three real parameters gamma_i which determine the
shape of the deformed 5-sphere. The dual gauge theory has the same field
content as N=4 SYM theory, but with scalar and Yukawa interactions ``deformed''
by gamma_i-dependent phases. The special case of equal deformation parameters
gamma_i=gamma corresponds to the N=1 supersymmetric deformation. We compare the
energies of semiclassical strings with three large angular momenta to the
1-loop anomalous dimensions of the corresponding gauge-theory scalar operators
and find that they match as it was the case in the SU(3) sector of the standard
AdS/CFT duality. In the supersymmetric case of equal gamma_i this extends the
result of our previous work (hep-th/0503192) from the 2-spin to the 3-spin
sector. This extension turns out to be quite nontrivial. To match the
corresponding low-energy effective ``Landau-Lifshitz'' actions on the string
theory and the gauge theory sides one is to make a special choice of the spin
chain Hamiltonian representing the 1-loop gauge theory dilatation operator.
This choice is adapted to low-energy approximation, i.e. it allows one to
capture the right vacuum states and the macroscopic spin wave sector of states
of the spin chain in the continuum coherent state effective action.Comment: 43 pages, Latex; v2:Discussion of 0-modes improved in section 2,
Appendix B expanded to demonstrate agreement between gauge and string theory
for 0-mode fluctuations; references added; v3: Modification to the discussion
on the U(1) factor in sec.4.
Conformally Exact Black Hole Perturbed by a Marginal Operator
We have examined effective theory induced by gauged WZW models, in which the
tachyon field is added as a marginal operator. Due to this operator added, we
must further add the higher order corrections, which modifies the original
configuration, to make the theory full-conformally invariant. It has been found
that 2d is a critical dimension in the sense that the metric obtained from
gauged WZW is modified by the tachyon condensation for , but not for .Comment: 11 pages Latex, FIT-HE-94-8
DILATONIC GRAVITY NEAR TWO DIMENSIONS AND ASYMPTOTIC FREEDOM OF THE GRAVITATIONAL COUPLING CONSTANT
Two models of dilatonic gravity are investigated: (i) dilaton-Yang-Mills
gravity and (ii) higher-derivative dilatonic gravity. Both are renormalizable
in dimensions and have a smooth limit for . The corresponding one-loop effective actions and beta-functions are found.
Both theories are shown to possess a non-trivial ultraviolet fixed point ---for
all dilatonic couplings--- in which the gravitational constant is
asymptotically free. It is shown that in the regime of asymptotic freedom the
matter central charge can be significantly increased by two different
mechanisms ---as compared with pure dilatonic gravity, where .Comment: LaTeX, 10 pages, no figure
Chemical and physical properties of bulk aerosols within four sectors observed during TRACE-P
Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the majority of the aerosol mass comprised of non-sea-salts, however, soot is also relatively important in this region. NNW had the highest mean sea salt mixing ratios, with the aerosol mass at low altitudes (\u3c2 km) evenly divided between sea salts, non-sea-salts, and dust. The highest mean mixing ratios of water-soluble ions and soot were observed at the lowest altitudes (\u3c2 km) in the Channel sector. The bulk of the aerosol mass exported from Asia emanates from Channel at both low and midaltitudes, due to the prevalence of dust compared to other sectors. Number densities show enhanced fine particles for Channel and NNW, while their volume distributions are enhanced due to sea salt and dust. Low-altitude Channel exhibits the highest condensation nuclei (CN) number densities along with enhanced scattering coefficients, compared to the other sectors. At midaltitudes (2â7 km), low mean CN number densities coupled with a high proportion of nonvolatile particles (â„65%) observed in polluted sectors (Channel and NNW) are attributed to wet scavenging which removes hygroscopic CN particles. Low single scatter albedo in SE Asia reflects enhanced soot
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Reactive nitrogen in Asian continental outflow over the western Pacific: Results from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) airborne mission
We present here results for reactive nitrogen species measured aboard the NASA DC-8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE-P) mission. The large-scale distributions total reactive nitrogen (NOy,sum = NO + NO2 + HNO3 + PAN + C1âC5alkyl nitrates) and O3 and CO were better defined in the boundary layer with significant degradation of the relationships as altitude increased. Typically, NOy,sum was enhanced over background levels of âŒ260 pptv by 20-to-30-fold. The ratio C2H2/CO had values of 1â4 at altitudes up to 10 km and as far eastward as 150°E, implying significant vertical mixing of air parcels followed by rapid advection across the Pacific. Analysis air parcels originating from five principal Asian source regions showed that HNO3 and PAN dominated NOy,sum. Correlations of NOy,sum with C2Cl4 (urban tracer) were not well defined in any of the source regions, and they were only slightly better with CH3Cl (biomass tracer). Air parcels over the western Pacific contained a complex mixture of emission sources that are not easily resolvable as shown by analysis of the Shanghai mega-city plume. It contained an intricate mixture of pollution emissions and exhibited the highest mixing ratios of NOy,sum species observed during TRACE-P. Comparison of tropospheric chemistry between the earlier PEM-West B mission and the recent TRACE-P data showed that in the boundary layer significant increases in the mixing ratios of NOy,sum species have occurred, but the middle and upper troposphere seems to have been affected minimally by increasing emissions on the Asian continent over the last 7 years
Non-linear sigma models with anti-de Sitter target spaces
We present evidence that there is a non-trivial fixed point for the AdS_{D+1}
non-linear sigma model in two dimensions, without any matter fields or
additional couplings beyond the standard quadratic action subject to a
quadratic constraint. A zero of the beta function, both in the bosonic and
supersymmetric cases, appears to arise from competition between one-loop and
higher loop effects. A string vacuum based on such a fixed point would have
string scale curvature. The evidence presented is based on fixed-order
calculations carried to four loops (corresponding to O(\alpha'^3) in the
spacetime effective action) and on large D calculations carried to O(D^{-2})
(but to all orders in \alpha'). We discuss ways in which the evidence might be
misleading, and we discuss some features of the putative fixed point, including
the central charge and an operator of negative dimension. We speculate that an
approximately AdS_5 version of this construction may provide a holographic dual
for pure Yang-Mills theory, and that quotients of an AdS_3 version might stand
in for Calabi-Yau manifolds in compactifications to four dimensions.Comment: 44 pages, 4 figures. v2: references adde
Online Handbook of Argumentation for AI: Volume 4
This volume contains revised versions of the papers selected for the fourth
volume of the Online Handbook of Argumentation for AI (OHAAI). Previously,
formal theories of argument and argument interaction have been proposed and
studied, and this has led to the more recent study of computational models of
argument. Argumentation, as a field within artificial intelligence (AI), is
highly relevant for researchers interested in symbolic representations of
knowledge and defeasible reasoning. The purpose of this handbook is to provide
an open access and curated anthology for the argumentation research community.
OHAAI is designed to serve as a research hub to keep track of the latest and
upcoming PhD-driven research on the theory and application of argumentation in
all areas related to AI
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