267,202 research outputs found
Efficient Resource Matching in Heterogeneous Grid Using Resource Vector
In this paper, a method for efficient scheduling to obtain optimum job
throughput in a distributed campus grid environment is presented; Traditional
job schedulers determine job scheduling using user and job resource attributes.
User attributes are related to current usage, historical usage, user priority
and project access. Job resource attributes mainly comprise of soft
requirements (compilers, libraries) and hard requirements like memory, storage
and interconnect. A job scheduler dispatches jobs to a resource if a job's hard
and soft requirements are met by a resource. In current scenario during
execution of a job, if a resource becomes unavailable, schedulers are presented
with limited options, namely re-queuing job or migrating job to a different
resource. Both options are expensive in terms of data and compute time. These
situations can be avoided, if the often ignored factor, availability time of a
resource in a grid environment is considered. We propose resource rank
approach, in which jobs are dispatched to a resource which has the highest rank
among all resources that match the job's requirement. The results show that our
approach can increase throughput of many serial / monolithic jobs.Comment: 10 page
Cluster Evaluation of Density Based Subspace Clustering
Clustering real world data often faced with curse of dimensionality, where
real world data often consist of many dimensions. Multidimensional data
clustering evaluation can be done through a density-based approach. Density
approaches based on the paradigm introduced by DBSCAN clustering. In this
approach, density of each object neighbours with MinPoints will be calculated.
Cluster change will occur in accordance with changes in density of each object
neighbours. The neighbours of each object typically determined using a distance
function, for example the Euclidean distance. In this paper SUBCLU, FIRES and
INSCY methods will be applied to clustering 6x1595 dimension synthetic
datasets. IO Entropy, F1 Measure, coverage, accurate and time consumption used
as evaluation performance parameters. Evaluation results showed SUBCLU method
requires considerable time to process subspace clustering; however, its value
coverage is better. Meanwhile INSCY method is better for accuracy comparing
with two other methods, although consequence time calculation was longer.Comment: 6 pages, 15 figure
Computational Study of the Structure and Thermodynamic Properties of Ammonium Chloride Clusters Using a Parallel J-Walking Approach
The thermodynamic and structural properties of (NHCl) clusters,
n=3-10 are studied. Using the method of simulated annealing, the geometries of
several isomers for each cluster size are examined. Jump-walking Monte Carlo
simulations are then used to compute the constant-volume heat capacity for each
cluster size over a wide temperature range. To carry out these simulations a
new parallel algorithm is developed using the Parallel Virtual Machine (PVM)
software package. Features of the cluster potential energy surfaces, such as
energy differences among isomers and rotational barriers of the ammonium ions,
are found to play important roles in determining the shape of the heat capacity
curves.Comment: Journal of Chemical Physics, accepted for publicatio
Synthesis of Topological Quantum Circuits
Topological quantum computing has recently proven itself to be a very
powerful model when considering large- scale, fully error corrected quantum
architectures. In addition to its robust nature under hardware errors, it is a
software driven method of error corrected computation, with the hardware
responsible for only creating a generic quantum resource (the topological
lattice). Computation in this scheme is achieved by the geometric manipulation
of holes (defects) within the lattice. Interactions between logical qubits
(quantum gate operations) are implemented by using particular arrangements of
the defects, such as braids and junctions. We demonstrate that junction-based
topological quantum gates allow highly regular and structured implementation of
large CNOT (controlled-not) gate networks, which ultimately form the basis of
the error corrected primitives that must be used for an error corrected
algorithm. We present a number of heuristics to optimise the area of the
resulting structures and therefore the number of the required hardware
resources.Comment: 7 Pages, 10 Figures, 1 Tabl
Computing k-Modal Embeddings of Planar Digraphs
Given a planar digraph G and a positive even integer k, an embedding of G in the plane is k-modal, if every vertex of G is incident to at most k pairs of consecutive edges with opposite orientations, i.e., the incoming and the outgoing edges at each vertex are grouped by the embedding into at most k sets of consecutive edges with the same orientation. In this paper, we study the k-Modality problem, which asks for the existence of a k-modal embedding of a planar digraph. This combinatorial problem is at the very core of a variety of constrained embedding questions for planar digraphs and flat clustered networks.
First, since the 2-Modality problem can be easily solved in linear time, we consider the general k-Modality problem for any value of k>2 and show that the problem is NP-complete for planar digraphs of maximum degree Delta <= k+3. We relate its computational complexity to that of two notions of planarity for flat clustered networks: Planar Intersection-Link and Planar NodeTrix representations. This allows us to answer in the strongest possible way an open question by Di Giacomo [https://doi.org/10.1007/978-3-319-73915-1_37], concerning the complexity of constructing planar NodeTrix representations of flat clustered networks with small clusters, and to address a research question by Angelini et al. [https://doi.org/10.7155/jgaa.00437], concerning intersection-link representations based on geometric objects that determine complex arrangements. On the positive side, we provide a simple FPT algorithm for partial 2-trees of arbitrary degree, whose running time is exponential in k and linear in the input size. Second, motivated by the recently-introduced planar L-drawings of planar digraphs [https://doi.org/10.1007/978-3-319-73915-1_36], which require the computation of a 4-modal embedding, we focus our attention on k=4. On the algorithmic side, we show a complexity dichotomy for the 4-Modality problem with respect to Delta, by providing a linear-time algorithm for planar digraphs with Delta <= 6. This algorithmic result is based on decomposing the input digraph into its blocks via BC-trees and each of these blocks into its triconnected components via SPQR-trees. In particular, we are able to show that the constraints imposed on the embedding by the rigid triconnected components can be tackled by means of a small set of reduction rules and discover that the algorithmic core of the problem lies in special instances of NAESAT, which we prove to be always NAE-satisfiable - a result of independent interest that improves on Porschen et al. [https://doi.org/10.1007/978-3-540-24605-3_14]. Finally, on the combinatorial side, we consider outerplanar digraphs and show that any such a digraph always admits a k-modal embedding with k=4 and that this value of k is best possible for the digraphs in this family
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