641 research outputs found
Equitable coloring of planar graphs with maximum degree at least eight
The Chen-Lih-Wu Conjecture states that each connected graph with maximum
degree that is not the complete graph or the
complete bipartite graph admits an equitable coloring with
colors. For planar graphs, the conjecture has been confirmed for
by Yap and Zhang and for by Nakprasit. In
this paper, we present a proof that confirms the conjecture for graphs
embeddable into a surface with non-negative Euler characteristic with maximum
degree and for planar graphs with maximum degree .Comment: 19 pages, 3 figure
Regular Abstractions for Array Systems
Verifying safety and liveness over array systems is a highly challenging
problem. Array systems naturally capture parameterized systems such as
distributed protocols with an unbounded number of processes. Such distributed
protocols often exploit process IDs during their computation, resulting in
array systems whose element values range over an infinite domain. In this
paper, we develop a novel framework for proving safety and liveness over array
systems. The crux of the framework is to overapproximate an array system as a
string rewriting system (i.e. over a finite alphabet) by means of a new
predicate abstraction that exploits the so-called indexed predicates. This
allows us to tap into powerful verification methods for string rewriting
systems that have been heavily developed in the last few decades (e.g. regular
model checking). We demonstrate how our method yields simple, automatically
verifiable proofs of safety and liveness properties for challenging examples,
including Dijkstra's self-stabilizing protocol and the Chang-Roberts leader
election protocol
A High-Performance Triple Patterning Layout Decomposer with Balanced Density
Triple patterning lithography (TPL) has received more and more attentions
from industry as one of the leading candidate for 14nm/11nm nodes. In this
paper, we propose a high performance layout decomposer for TPL. Density
balancing is seamlessly integrated into all key steps in our TPL layout
decomposition, including density-balanced semi-definite programming (SDP),
density-based mapping, and density-balanced graph simplification. Our new TPL
decomposer can obtain high performance even compared to previous
state-of-the-art layout decomposers which are not balanced-density aware, e.g.,
by Yu et al. (ICCAD'11), Fang et al. (DAC'12), and Kuang et al. (DAC'13).
Furthermore, the balanced-density version of our decomposer can provide more
balanced density which leads to less edge placement error (EPE), while the
conflict and stitch numbers are still very comparable to our
non-balanced-density baseline
Extramedullary versus intramedullary tibial alignment technique in total knee arthroplasty: A meta-analysis of randomized controlled trials
The aim of this study was to establish whether the use of an extramedullary or intramedullary tibial cutting guide leads to superior mechanical leg axis and implant positioning. A meta-analysis of six randomized controlled trials including 350 knees was performed. For the mechanical axis, frontal tibial component angle and tibial slope, there were no significant differences in the mean values or the number of outliers (±3°) between the extramedullary and intramedullary groups. A reduced tourniquet time was associated with the intramedullary guide. No significant difference in the complication rate was noted between the two groups. Neither extramedullary nor intramedullary tibial alignment was more accurate in facilitating the tibial cut. Use of an intramedullary guide results in a shorter tourniquet time and exhibits a similar complication rate as the extramedullary guide
CSS Minification via Constraint Solving
Minification is a widely-accepted technique which aims at reducing the size
of the code transmitted over the web. We study the problem of minifying
Cascading Style Sheets (CSS) --- the de facto language for styling web
documents. Traditionally, CSS minifiers focus on simple syntactic
transformations (e.g. shortening colour names). In this paper, we propose a new
minification method based on merging similar rules in a CSS file.
We consider safe transformations of CSS files, which preserve the semantics
of the CSS file. The semantics of CSS files are sensitive to the ordering of
rules in the file. To automatically identify a rule merging opportunity that
best minimises file size, we reduce the rule-merging problem to a problem on
CSS-graphs, i.e., node-weighted bipartite graphs with a dependency ordering on
the edges, where weights capture the number of characters (e.g. in a selector
or in a property declaration). Roughly speaking, the corresponding CSS-graph
problem concerns minimising the total weight of a sequence of bicliques
(complete bipartite subgraphs) that covers the CSS-graph and respects the edge
order.
We provide the first full formalisation of CSS3 selectors and reduce
dependency detection to satisfiability of quantifier-free integer linear
arithmetic, for which highly-optimised SMT-solvers are available. To solve the
above NP-hard graph optimisation problem, we show how Max-SAT solvers can be
effectively employed. We have implemented our algorithms using Max-SAT and
SMT-solvers as backends, and tested against approximately 70 real-world
examples (including the top 20 most popular websites). In our benchmarks, our
tool yields larger savings than six well-known minifiers (which do not perform
rule-merging, but support many other optimisations). Our experiments also
suggest that better savings can be achieved in combination with one of these
six minifiers
Monadic Decomposability of Regular Relations
Monadic decomposibility - the ability to determine whether a formula in a given logical theory can be decomposed into a boolean combination of monadic formulas - is a powerful tool for devising a decision procedure for a given logical theory. In this paper, we revisit a classical decision problem in automata theory: given a regular (a.k.a. synchronized rational) relation, determine whether it is recognizable, i.e., it has a monadic decomposition (that is, a representation as a boolean combination of cartesian products of regular languages). Regular relations are expressive formalisms which, using an appropriate string encoding, can capture relations definable in Presburger Arithmetic. In fact, their expressive power coincide with relations definable in a universal automatic structure; equivalently, those definable by finite set interpretations in WS1S (Weak Second Order Theory of One Successor). Determining whether a regular relation admits a recognizable relation was known to be decidable (and in exponential time for binary relations), but its precise complexity still hitherto remains open. Our main contribution is to fully settle the complexity of this decision problem by developing new techniques employing infinite Ramsey theory. The complexity for DFA (resp. NFA) representations of regular relations is shown to be NLOGSPACE-complete (resp. PSPACE-complete)
Regulation of subcellular location and activity of Cdc2-cyclinb1 is involved in bendamustine-induced G2 arrest
Bendamustine is a multifunctional alkylating agent for the treatment of multiple myeloma, with the G2/M arrest-induction ability in human multiple myeloma RPMI-8226 cells, but the mechanism remains ambiguous. In this study, we found bendamustine caused the G2 arrest in 24 h, regulated the phosphorylation status of Cdc2, and blocked the nuclear import of Cdc2-CyclinB1 complex. Pretreatment with ATM/ATR inhibitor caffeine or p38 MAPK inhibitor SB203580 suppressed the phosphorylation of Cdc2 at Thr14/Tyr15 or attenuate the blockade of nuclear import, respectively; however, neither of these two inhibitors nor the combination imposed significant effects on Bendamustine-triggered G2 arrest. Bendamustine-induced blockade of the nuclear translocation dissipated after 48 h, after which, the G2 arrest was maintained through the inhibitory phosphorylation of Cdc2. Taken together, our research suggested that two or more pathways and mechanisms which regulated the cell cycle in a time-dependent manner were involved in the G2 arrest invoked by bendamustine.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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