Narrow Results

In this paper, we study the concept of nearness between $L$-fuzzy rough sets and the concepts of $L$-fuzzy rough grills and $L$-fuzzy rough ${\delta }_{{ℱ}}$-clusters on a Čech $L$-fuzzy rough proximity space $(X,{\delta }_{{ℱ}})$. Also, we investigate the relationship among $L$-fuzzy rough grills, $L$-fuzzy rough ${\delta }_{{ℱ}}$-clan and $L$-fuzzy rough ${\delta }_{{ℱ}}$-clusters. Moreover, we introduce the $L$-fuzzy rough LO-proximity spaces and study some of its basic properties. An adequate number of examples support the study.

The way in which an opinion rejecting reform can finally become the consensus of everyone was studied by Galam (2002) in a probabilistic model. We now replace his clusters by those formed via random percolation by letting particles diffuse on a lattice. Galam's rejection of reform is reproduced below the percolation threshold, whereas at and above the threshold, approval of a reform also becomes possible.

Here is a sand-pile introduced by Bak et al. The system accumulates particles one by one. From time to time it topples. Every toppling initiates an event. The distribution of the events' size follows a power law for all the events except the strongest ones. The fraction of the strongest events does not depend on the system length. The number of particles and their clustering increase before the strongest events.

Using molecular dynamics and thermal quenching methods on the basis of Voter–Chen version of the embedded-atom method, we have studied the melting behavior of Au_N (N = 12, 13, 14) clusters. This behavior is described in terms of overall and atom resolved root-mean-square bond-length fluctuations, specific-heat, short- and long-time average coordination numbers of each atom and short-time average temperatures of the clusters. The isomer sampling probabilities are obtained from the thermal quenching of the molten clusters, and their energy-spectrum widths are investigated. Phase change of a cluster takes place with the collective and simultaneous motion of all the atoms.

In this paper, a complex network is constructed as comprising "clusters" which can be interpreted as a group of people with regular contacts. In each "cluster" individuals contact fully. A given individual contact individuals in other "clusters" by links. Then we study the dynamical behavior of the epidemiological model in this complex network, and discuss the influence of the intra-cluster infection probability, the extra-cluster infection probability, and infection time before being detected on epidemic dynamics. The results show that extra-cluster infection reduction, early detection and swift isolation are good infection control practices.

This paper deals with the molecular dynamics simulation (MDS) of nanofluid under Poiseuille flow in a model nanochannel. The nanofluid is created by exerting four solid nanoparticles dispersed in Argon (Ar), as base fluid, between two parallel solid walls. The flow is simulated by molecules with the Lennard-Jones (LJ) intermolecular potential function. Different simulations are done with two different types of solid particles and two cut-off radii. In each case, Copper (Cu) and Platinum (Pt) LJ parameters are applied for the nanoparticles and solid walls particles with cut-off ratios of 2.2σ and 2.5σ. The microstructure of the system at different time steps is investigated to describe the aggregation kinetics of nanofluid on Poiseuille flow. When a few nanoparticles or a cluster of them reach each other, they stick together and the interaction surface of the solid–fluid interface reduces, so the potential energy of the system decreases at these time steps. Therefore, the system enthalpy reduces at the aggregation time steps. Results show that the simulations with cut-off radius 2.5σ indicate minimum clustering effect at the same time. Based on the obtained results, the system with Cu nanoparticles makes it to aggregate later than that of Pt nanoparticles which is due to differences in potential interaction of two materials. The new simulation results enhance our understanding of cluster morphology and aggregation mechanisms.

In recent years, community detection has gradually become a hot topic in the complex network data mining field. The research of community detection is helpful not only to understand network topology structure but also to explore network hiding function. In this paper, we improve FluidC which is a novel community detection algorithm based on fluid propagation, by ameliorating the quality of seed set based on positive feedback and determining the node update order. We first summarize the shortcomings of FluidC and analyze the reasons result in these drawbacks. Then, we took some effective measures to overcome them and proposed an efficient community detection algorithm, called FluidC+. Finally, experiments on the generated network and real-world network show that our method not only greatly improves the performance of the original algorithm FluidC but also is better than many state-of-the-art algorithms, especially in the performance on real-world network with ground truth.

In this paper, the structural and dynamical properties of the 19-atom double icosahedral silver cluster are studied by using the classical molecular dynamics. It is found that the melting of the 19-atom cluster starts with the migrations of the surface atoms. The surface atoms can interchange positions with each other atoms through three ways. The first and second ways involve with only part of the surface atoms. The third way can involve the surface atoms at all symmetrical positions. With the increase of temperature, the inner atoms can hop onto the surface of the cluster and the position interchange between the surface atoms and the inner atoms can be realized. With further increase of temperature, the isomerization of the cluster becomes frequent and the motion of the atoms of the cluster becomes more and more disordered. When the temperature reaches the value corresponding to the second peak of the heat capacity, the solid cluster turns into the fully melted state.

We review Monte Carlo computer simulations of spin models — both discrete and continuous. We explain the phenomenon of critical slowing which seriously degrades the efficiency of standard local Monte Carlo algorithms such as the Metropolis algorithm near phase transitions. We then go onto describe in detail the new algorithms which ameliorate the problem of critical slowing down, and give their dynamical critical exponent values.

The Basic Interface for Parallelism (BIP) [1] is a low-level communication system for Myrinet programmable network interface cards (NIC). On one hand BIP has proven that a very small latency and a very large throughput can be delivered. On another hand hardware implementations, like Giganet or NICs that implement the Scalable Coherent Interface (SCI), demonstrate very good performance for medium-sized messages. Our aim in this paper is to study how the programmable NICs can compare with the hardware solutions for medium-sized messages. We built a very precise model of the pipeline behavior driven by the NIC program in order to identify the bottlenecks. The results show that the pipeline quality is critical. We have developed an adaptive strategy as in [2] and then introduced it in BIP. Experiments show up to a two-fold gain over the previous BIP results and reach performances above the hardware solutions.

Virtual Interface Architecture(VIA) is a light-weight protocol for protected user-level zero-copy communication. In spite of the promised high performance of VIA, previous MPI implementations for GigaNet's cLAN revealed low communication performance. Two main sources of such low performance are the discrepancy in the communication model between MPI and VIA and the multi-threading overhead. In this paper, we propose a new implementation of the Bulk Synchronous Parallel(BSP) programming library for VIA called xBSP to overcome such problems. To the best of our knowledge, xBSP is the first implementation of the BSP library for VIA. xBSP demonstrates that the selection of a proper library is important to exploit the features of light-weight protocols. Intensive use of Remote Direct Memory Access(RDMA) operations leads to high performance close to the native VIA performance with respect to round trip delay and bandwidth. Considering the effects of multi-threading, memory registration, and completion policy on performance, we could obtain an efficient BSP implementation for cLAN, which was confirmed by experimental results.

Structures of excited states in ¹¹C and ¹¹B were studied based on variational calculations after spin-parity projection in a framework of antisymmetrized molecular dynamics (AMD). The calculations systematically reproduce experimental data of the transition strengths such as Gamov-Teller(GT) and M1 transitions. A well-developed cluster structure of 2α+³He(t) was found in the state of ¹¹C(¹¹B). We assigned this state to the observed state at 8 MeV. The calculations reproduce the small which has been measured in the recent experiments. It was found that the state has a dilute cluster state, and its features are similar to those of the which is considered to be a gas state of three α clusters.

t+t clustering in He isotopes is investigated by using two theoretical approaches. A role of the t+t cluster component in the ground state is examined with AMD triple-S, allowing the wider configuration space containing simultaneously the "t+t+valence neutrons" structure and "⁴He+valence neutrons" structure. We understand the importance of the t+t component even for the ground state. Further, t+t resonances are investigated with RGM type approach. We obtained many t+t states as resonances near to t+t threshold.

We developed an m-scheme approach of the cluster-orbital shell model formalism. The radial wave function is treated as the super position of the Gaussian functions with different width parameters. Energies and r.m.s. radii of oxygen isotopes are studied.

We have developed an m-scheme cluster-orbital shell model approach to study neutron- and proton-rich nuclei toward the drip-lines. We discuss the property of the neutron-rich oxygen isotopes with analyzing the relation between the energy and r.m.s. radius.

Cluster radioactivity is a rare cold nuclear process which is intermediate between alpha decay and spontaneous fission. The present work is a theoretical investigation of the feasibility of alpha decay and cluster radioactivity from proton rich Osmium (Os) isotopes with mass number ranging from 162–190. Osmium forms a part of the transition region between highly deformed and spherical nuclei. Calculations have been done using unified fission model and Hartree–Fock–Bogoliubov (HFB) theory. We have chosen only those decays with half-lives falling in measurable range. Geiger–Nuttall plot has been successfully reproduced. The isotope which is most favorable to each decay mode has a magic daughter nucleus.

The supremacy of quantum approach is able to solve the problems which are not practically feasible on classical machines. It suggests a significant speed up of the simulations and decreases the chance of error rates. This paper introduces a new quantum model for time series data which depends on the appropriate length of intervals. To provide effective solution of this problem, this study suggests a new graph-based quantum approach. This technique is useful in discretization and representation of logical relationships. Then, we divide these logical relations into various groups to obtain efficient results. The proposed model is verified and validated with various approaches. Experimental results signify that the proposed model is more precise than existing competing models.

The radiative transfer equations for multiple inverse Compton scattering of the Cosmic Microwave Background Radiation (CMBR) by the hot intra-cluster electrons are solved numerically. The spherical isothermal and inhomogeneous β model has been considered for the electron distribution. The anisotropy of the CMBR caused by scattering, known as thermal Sunyaev–Zel'dovich effect, along the radial axis of the medium is compared with the analytical solution of Kompaneets equation. The X-ray data of several clusters of galaxies at low redshifts provide an estimation of the central electron density n₀ to be of the order 10^-3. It is found that for this value of n₀ the effect of multiple scattering is negligible. The numerically calculated anisotropy along the radial axis matches well with the analytical solution that describes single scattering. The result incorporating multiple scattering is fitted with the recent observation of Sunyaev–Zel'dovich effect in the cluster Abell 2163. It is shown that if n₀ is greater by an order of magnitude, which could be possible for cluster of galaxies at comparatively higher redshift, multiple scattering would play a significant role at the Wien region of the anisotropy spectrum. A fitting formula for the correction to the Sunyaev–Zel'dovich effect due to multiple scattering is provided.

The amorphous Ni–Nb–Zr–H glassy alloy containing subnanometer-sized icosahedral Zr₅ Nb₅Ni₃ clusters exhibited four types of electronic phenomena: a metal/insulator transition, an electric current-induced voltage oscillation (Coulomb oscillation), giant capacitor behavior and an electron avalanche with superior resistivity. These findings could be excluded by charge density waves that the low-dimensional component of clusters, in which the atoms are lined up in chains along the [130] direction, plays important roles in various electron transport phenomena.

A promising method to generate the intense isolated attosecond sources has been theoretically investigated emerging from the two-dimensional Ar⁺ cluster driven in the two-color polarized gating pulse. The results show that with the introduction of the Ar⁺ cluster model, not only the harmonic cutoffs are extended, but also the harmonic yields are enhanced by at least two orders of magnitude compared with the single atom model. Further, by properly choosing the number of ions surrounding the central atom, the internuclear distance as well as the laser parameters, two isolated pulses with durations of 53 as and 46 as can be obtained.