293 research outputs found
A polynomial-time algorithm to solve the large scale of airplane refueling problem
Airplane refueling problem is a nonlinear combinatorial optimization problem
with feasible feasible solutions. Given a fleet of airplanes with
mid-air refueling technique, each airplane has a specific fuel capacity and
fuel consumption rate. The fleet starts to fly together to a same target and
during the trip each airplane could instantaneously refuel to other airplanes
and then be dropped out. The question is how to find the best refueling policy
to make the last remaining airplane travels the farthest. To solve the large
scale of the airplane refueling problem in polynomial-time, we propose the
definition of the sequential feasible solution by employing the data structural
properties of the airplane refueling problem. We prove that if an airplane
refueling problem has feasible solutions, it must have sequential feasible
solutions, and its optimal feasible solution must be the optimal sequential
feasible solution. Then we present the sequential search algorithm which has a
computational complexity that depends on the number of sequential feasible
solutions referred to , which is proved to be upper bounded by
as an exponential bound that lacks of applicability on larger input for worst
case. Therefore we investigate the complexity behavior of the sequential search
algorithm from dynamic perspective, and find out that is bounded by
when the input is greater than . Here is a
constant and is regarded as the "inflection point" of the complexity of
the sequential search algorithm from exponential-time to polynomial-time.
Moreover, we build an efficient computability scheme according to which we
shall predict the specific complexity of the sequential search algorithm to
choose a proper algorithm considering the available running time for decision
makers or users.Comment: 18 pages, 2 figure
The -vehicle exploration problem is NP-complete
The -vehicle exploration problem (NVEP) is a combinatorial optimization
problem, which tries to find an optimal permutation of a fleet to maximize the
length traveled by the last vehicle. NVEP has a fractional form of objective
function, and its computational complexity of general case remains open. We
show that Hamiltonian Path NVEP, and prove that NVEP is NP-complete.Comment: 5 pages, 6 figure
UVL: A Unified Framework for Video Tampering Localization
With the development of deep learning technology, various forgery methods
emerge endlessly. Meanwhile, methods to detect these fake videos have also
achieved excellent performance on some datasets. However, these methods suffer
from poor generalization to unknown videos and are inefficient for new forgery
methods. To address this challenging problem, we propose UVL, a novel unified
video tampering localization framework for synthesizing forgeries.
Specifically, UVL extracts common features of synthetic forgeries: boundary
artifacts of synthetic edges, unnatural distribution of generated pixels, and
noncorrelation between the forgery region and the original. These features are
widely present in different types of synthetic forgeries and help improve
generalization for detecting unknown videos. Extensive experiments on three
types of synthetic forgery: video inpainting, video splicing and DeepFake show
that the proposed UVL achieves state-of-the-art performance on various
benchmarks and outperforms existing methods by a large margin on cross-dataset
"Maps preserving the spectrum of generalized Jordan product of operators", and its "Addendum"
In the paper "Maps preserving the spectrum of generalized Jordan product of
operators", we define a generalized Jordan products on standard operator
algebras on complex Banach spaces , respectively. This
includes the usual Jordan product , and the
triple . Let a map prserving the spectra of the products whenever any one of
has rank at most one. It is shown in this paper that if the
range of contains all operators of rank at most three, then
must be a Jordan isomorphism multiplied by an th root of unity. Similar
results for maps between self-adjoint operators acting on Hilbert spaces are
also obtained.
After our paper "Maps preserving the spectrum of generalized Jordan product
of operators" was published in Linear Algebra Appl. 432 (2010), 1049-1069,
Jianlian Cui pointed out that some arguments in the proof of Theorem 3.1 are
not entirely clear and accurate. Here we supply some details in the "Addendum".Comment: 1. 29 pages, the "orginal paper". 2. 5 pages, the "Addendum". 3.
Replace the latex file of the "original paper" to avoid the conflict of using
an old version of 'natbib' at April 23, 2010. The newer version simply does
not use `natbib' at all, and nothing else is changed
Starch/microcrystalline cellulose hybrid gels as gastric-floating drug delivery systems
We report hybrid gels based on a high-amylose starch and microcrystalline cellulose with demonstrated properties for gastric-floating drug delivery purposes. The starch/cellulose gels were prepared by ionic liquid dissolution and regeneration, resulting in a continuous surface and a porous interior and a type-II crystalline structure of cellulose. These polysaccharide gels displayed satisfactory elasticity (0.88), recovery (0.26β0.36) and equilibrium swelling (1013β1369%). The hybrid gels were loaded with ranitidine hydrochloride as a model drug and subsequently, low-density starch/cellulose tablets were fabricated by vacuum-freeze-drying. In vitro tests in a simulated gastric fluid indicate that the 3:7 (wt./wt.) starch/cellulose system could maintain the buoyancy for up to 24 h with a release of 45.87% for the first 1 h and a sustained release for up to 10 h. Therefore, our results have demonstrated the excellent gastric-floating ability and sustainable drug release behavior of the starch/cellulose hybrid gels
Human genome-wide repair map of DNA damage caused by the cigarette smoke carcinogen benzo[a]pyrene
Benzo[a]pyrene (BaP) is a widespread potent carcinogen found in food, coal tar, cigarette smoke, and industrial smoke. Cigarette smoking is the leading cause of lung cancer, and the mutagenesis in smoking-associated lung cancer is determined by multiple factors, including nucleotide excision repair. We have developed a general method for genome-wide mapping of nucleotide excision repair at single-nucleotide resolution and applied it to generate repair maps of UV- and BaP-induced DNA damage in human. Results show a novel sequence specificity of BaP diol epoxide-deoxyguanosine repair. This general method can be used to study repair of all types of DNA damages that undergo nucleotide excision repair
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