32,512 research outputs found
On Feedback Vertex Set: New Measure and New Structures
We present a new parameterized algorithm for the {feedback vertex set}
problem ({\sc fvs}) on undirected graphs. We approach the problem by
considering a variation of it, the {disjoint feedback vertex set} problem ({\sc
disjoint-fvs}), which finds a feedback vertex set of size that has no
overlap with a given feedback vertex set of the graph . We develop an
improved kernelization algorithm for {\sc disjoint-fvs} and show that {\sc
disjoint-fvs} can be solved in polynomial time when all vertices in have degrees upper bounded by three. We then propose a new
branch-and-search process on {\sc disjoint-fvs}, and introduce a new
branch-and-search measure. The process effectively reduces a given graph to a
graph on which {\sc disjoint-fvs} becomes polynomial-time solvable, and the new
measure more accurately evaluates the efficiency of the process. These
algorithmic and combinatorial studies enable us to develop an
-time parameterized algorithm for the general {\sc fvs} problem,
improving all previous algorithms for the problem.Comment: Final version, to appear in Algorithmic
Biconditional Generative Adversarial Networks for Multiview Learning with Missing Views
In this paper, we present a conditional GAN with two generators and a common
discriminator for multiview learning problems where observations have two
views, but one of them may be missing for some of the training samples. This is
for example the case for multilingual collections where documents are not
available in all languages. Some studies tackled this problem by assuming the
existence of view generation functions to approximately complete the missing
views; for example Machine Translation to translate documents into the missing
languages. These functions generally require an external resource to be set and
their quality has a direct impact on the performance of the learned multiview
classifier over the completed training set. Our proposed approach addresses
this problem by jointly learning the missing views and the multiview classifier
using a tripartite game with two generators and a discriminator. Each of the
generators is associated to one of the views and tries to fool the
discriminator by generating the other missing view conditionally on the
corresponding observed view. The discriminator then tries to identify if for an
observation, one of its views is completed by one of the generators or if both
views are completed along with its class. Our results on a subset of Reuters
RCV1/RCV2 collections show that the discriminator achieves significant
classification performance; and that the generators learn the missing views
with high quality without the need of any consequent external resource.Comment: 15 pages, 3 figur
Functionalisation of Carbon-Fluorine Bonds with Main Group Reagents
Synthetic approaches to produce reactive chemical building blocks from fluorinated molecules by the functionalization of carbonâfluorine bonds with main group reagents are reviewed. The reaction types can be categorized as: (i) the formal 1,2-addition of CâF bonds across SiâSi, BâB, or MgâMg bonds; (ii) the oxidative addition of CâF bonds to Si(II), Ge(II), and Al(I) centres; and (iii) the dehydrogenative coupling of CâF bonds with AlâH or BâH bonds. Many of the advances have emerged between 2015â2016 and are largely focused upon aromatic substrates that contain sp2 CâF bonds
Challenges of Internet of Things and Big Data Integration
The Internet of Things anticipates the conjunction of physical gadgets to the
In-ternet and their access to wireless sensor data which makes it expedient to
restrain the physical world. Big Data convergence has put multifarious new
opportunities ahead of business ventures to get into a new market or enhance
their operations in the current market. considering the existing techniques and
technologies, it is probably safe to say that the best solution is to use big
data tools to provide an analytical solution to the Internet of Things. Based
on the current technology deployment and adoption trends, it is envisioned that
the Internet of Things is the technology of the future, while to-day's
real-world devices can provide real and valuable analytics, and people in the
real world use many IoT devices. Despite all the advertisements that companies
offer in connection with the Internet of Things, you as a liable consumer, have
the right to be suspicious about IoT advertise-ments. The primary question is:
What is the promise of the Internet of things con-cerning reality and what are
the prospects for the future.Comment: Proceedings of the International Conference on International
Conference on Emerging Technologies in Computing 2018 (iCETiC '18), 23rd
-24th August, 2018, at London Metropolitan University, London, UK, Published
by Springer-Verla
The Primary Spin-4 Casimir Operators in the Holographic SO(N) Coset Minimal Models
Starting from SO(N) current algebra, we construct two lowest primary higher
spin-4 Casimir operators which are quartic in spin-1 fields. For N is odd, one
of them corresponds to the current in the WB_{\frac{N-1}{2}} minimal model. For
N is even, the other corresponds to the current in the WD_{\frac{N}{2}} minimal
model. These primary higher spin currents, the generators of wedge subalgebra,
are obtained from the operator product expansion of fermionic (or bosonic)
primary spin-N/2 field with itself in each minimal model respectively. We
obtain, indirectly, the three-point functions with two real scalars, in the
large N 't Hooft limit, for all values of the 't Hooft coupling which should be
dual to the three-point functions in the higher spin AdS_3 gravity with matter.Comment: 65 pages; present the main results only and to appear in JHEP where
one can see the Appendi
Conical Defects in Higher Spin Theories
We study conical defect geometries in the SL(N) Chern-Simons formulation of
higher spin gauge theories in AdS_3. We argue that (for N\geq 4) there are
special values of the deficit angle for which these geometries are actually
smooth configurations of the underlying theory. We also exhibit a gauge in
which these geometries can be viewed as wormholes interpolating between two
distinct asymptotically AdS_3 spacetimes. Remarkably, the spectrum of smooth
SL(N,C) solutions, after an appropriate analytic continuation, exactly matches
that of the so-called "light primaries" in the minimal model W_N CFTs at finite
N. This gives a candidate bulk interpretation of the latter states in the
holographic duality proposed in [1].Comment: 38 page
The Coset Spin-4 Casimir Operator and Its Three-Point Functions with Scalars
We find the GKO coset construction of the dimension 4 Casimir operator that
contains the quartic WZW currents contracted with completely symmetric SU(N)
invariant tensors of ranks 4, 3, and 2. The requirements, that the operator
product expansion with the diagonal current is regular and it should be primary
under the coset Virasoro generator of dimension 2, fix all the coefficients in
spin-4 current, up to two unknown coefficients. The operator product expansion
of coset primary spin-3 field with itself fixes them completely. We compute the
three-point functions with scalars for all values of the 't Hooft coupling in
the large N limit. At fixed 't Hooft coupling, these three-point functions are
dual to that found by Chang and Yin recently in the undeformed AdS_3 bulk
theory (higher spin gravity with matter).Comment: 65 pages; the ambiguity for the two coefficient functions is
clarified and the abstract, the introduction, the subsection 3.4 and the
conclusion are improved and to appear in JHE
The inter-scale behaviour of two natural scaly clays
This paper describes the results of an experimental investigation of the inter-scale behaviour of two natural scaly clays. These have been tested by means of a custom-made inter-particle loading apparatus, which has enabled their mechanical response to be studied in both compression and shearing. The main features of the micromechanical behaviour of these clays have been compared, focusing on the influence of their composition, and the results are compared with those obtained testing the same materials using other devices (triaxial and ring shear apparatus). The results have shown that, contrary to expectations, the surfaces of the scales are not residual shear surfaces and the inter-scale angle of shearing resistance is actually closer to critical state or post-peak angles measured in conventional tests
Laser anneal of oxycarbosilane low-k film
Submilisecond laser anneal has been experimentally investigated for porogen removal and its ability to improve the mechanical strength in oxycarbosilane ultra low-k films compromised due to the introduction of porosity. We report the occurrence of extensive bond rearrangements inferred from Fourier-transform infra-red (FTIR) spectroscopy, elastic recoil detection (ERD) and spectroscopic ellipsometry (SE) in the energy range of 1.4-8 eV. The laser anneal affects most notably the organic content of the organosilicate matrix leading to depletion and reorganization. Nevertheless, the tested conditions reveal a processing window which allows for 13% improvement of Youngâs modulus as compared to the reference film, annealed in a conventional furnace at 400°C for 2 h, while not impacting the relative dielectric constant of 2.25
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