Many naturally occurring sweet-tasting proteins have been isolated and are largely expected to be available as a replacement for natural sugars and artificial sweeteners in the near future. We have carried out a large-scale all-electron quantum chemical calculation on des-pGlu brazzein, a sweet-tasting protein, and four different mutants by employing a density functional method program, ProteinDF, in order to examine a relationship between the sweetness of protein sweeteners and their electronic properties such as electrostatic potential and frontier molecular orbitals, HOMO and LUMO. ProteinDF all-electron canonical molecular orbital calculations toward des-pGlu brazzein and two different sweet-tatsting mutants, Asp29Lys and Glu41Lys, indicated that a number of amino acid residues including neutral amino acids, Tyr8 and Tyr51, have positive charge and especially for two mutants the positive charge widely spreads over each mutant. On the other hand, similar all-electron calculations for Arg33Ala and Arg43Ala mutants having a taste like water revealed that the number of amino acid residues with positive charge in these two mutants is less than that in des-pGlu brazzein and Asp29Lys and Glu41Lys mutants. In addition, we found that some positively charged amino acid residues occur in the HOMO and LUMO of des-pGlu brazzein and two sweet-tasting mutants.

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  Two-tier network which is comprised by conventional cellular networks and femtocell networks is provided to achieve higher user transmission rate and larger coverage. However, the throughput of multicell system is greatly limited by the cross-tier co-channel interference. Especially, the cell-edge user of the macrocell layer would suffer from low transmission rate due to the co-channel interference from nearby femtocells. In this paper, we address the resource allocation problem for Macro Cell-Edge Users (MCEUs) in heterogonous Macro-Femto network. Our objective is to maximize the multiple MCEUs' throughput by allowing them to access the unoccupied resource of nearby femtocells, depending on their willingness to rent the femtocell resources. The willingness is expressed as the proportional throughput relationship between users. We propose a mix integer programming algorithm based on Lagrange optimal method and solve it in two suboptimal schemes. The subchannels are first allocated with the assumption of equal power distribution. Then optimal power allocation is performed under the constraint of all the MCEUs throughput requirements. Simulation results validate that our proposal can effectively allocate power and channel resource to the MCEUs and achieve better throughput than the case when users are only served by Macrocell. Also, the fairness which is based on the payment willingness of these users can be satisfied.

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  This study utilizes a visualization to accurately display characteristics and dynamic behaviors of submesoscale vortices in a semi-enclosed bay by using the large amount of output of realistic ocean states produced by a high-resolution land-sea coupled model. A visualized image represents the three-dimensional features of the vortices on a daily basis. Dynamic behaviors of the vortex, such as the clockwise eddy in the bay, are effectively captured by depicting their circumferences and cores. As a result, the fluctuation of the clockwise eddy, which affects scallop production, is well simulated, as observed by previous studies. Further, we successfully describe formation and decay processes of the eddy in detail. In contrast to the descriptions from conventional analyses, our high-resolution ocean simulation and its visualization can provide better understanding of the dynamic behaviors of the vortex on short timescales (within a month) as it relates to coastal oceanography and aquaculture operation.

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  The sputtering yields of carbon due to low-energy xenon ion bombardment have been observed below the theoretical threshold energy for carbon sputtering. A Monte Carlo simulation code ACAT has been used to calculate carbon sputtering due to xenon ion bombardment. The yields of carbon calculated with ACTA for pure carbon target differ from the experimental yields. Meanwhile, the results of ACAT with 14% xenon atoms retained in graphite are in good agreement with the experimental data. The accumulation of incident xenon ions in carbon target plays a decisive role in reducing the threshold energy of sputtering and the carbon sputtering due to xenon ion bombardment is enhanced by the accumulation of xenon in carbon target. The results calculated with ACAT have indicated that the enhancement of sputtering yields depend on the mass ration of mass of a projectile to mass of a target atom.

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  Magnetic hysteresis curves were calculated using the Monte Carlo method to study the dependence of magnetic properties on the distribution of magnetic sites based on simple diffusion model. The simulated curves illustrate that the magnetic sites distributions influence strongly the magnetic remanence and coercivity depending on diffusion step. Furthermore, the clusters are divided into “colonies”, which are defined as groups of magnetic sites linked by the nearest neighbors, to analyze effect for the hysteresis curves of local structures of magnetic sites in the clusters. These results support that the magnetic sites dispersion system included localized bias determines its magnetic properties depending on the diffusion step, and they would be a new point of view for control of magnetic properties.

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  Visualization of numerical simulation data is necessary to intuitively understand natural phenomena or structures. However, today's massively parallel supercomputers output huge datasets from large scale high resolution simulations. Due to its size, it is difficult to extract informative data from these datasets. We suggest here the use of combining a feature extraction method and the creation of a transfer function in order to obtain an effective visualization method for ocean general circulation model data. Features such as ocean currents, vortices or water masses are extracted using multivariate analysis which clusters temperature, salinity fluid velocity, etc.

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  A finite integration method on three- and four-dimensional space-time grids is studied for electromagnetic wave computation, where a non-uniform time-step distribution is naturally introduced. A dual grid based on the Hodge duality and the Lorentzian metric is introduced to provide a simple constitutive relation for electromagnetic variables. An improved approximation of constitutive relation is proposed to suppress unphysical wave-reflection.

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  Owing to the success of micro electronics and parallel computing technology, the power and capacity of computer systems are extending. This advancement attaches hopes of paradigm shift in numerical methods, that is, further continuous extension of the power and capacity of parallel systems may gradually replace numerical methods done by floating-point to rational number arithmetic, which provides essentially different results from floating-point arithmetic. A rational number arithmetic provides us exact results, which is important in mathematical point of view. However the problem of the rational number arithmetic exists in its limitation to compute irrational numbers. In this paper, we propose how square root operations can be avoided by rational number arithmetic without rounding the number. In the first section, we describe introductions. In the second section, an implicit square root formulation in rational number arithmetic with an example of Schmidt orthogonalization. In the third section, we describe a naive method to compute eigenvalues of symmetric matrices in arbitrarily high precision. In the fourth section, we describe a new approach to transform symmetric matrix to tridiagonal matrix exactly by implicit square root formulation, and show an example to solve a multiple eigenvalue problem. In the final section, concluding remarks are described.

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  To analyze large scale 3-dimensional data, the modern virtual reality (VR) technology will play important roles in future simulation studies. Various VR visualization programs have been developed to date, including our original VR visualization software VFIVE. However, almost all of the previous VR software are based on CAVElib, which is a de facto standard commercial library for VR environments. To replace the basic API from CAVElib, we are developing a new visualization software based on VR Juggler which is an open source free software library. Our program design and implemented visualization methods are reported in this paper.

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  The immersive virtual environments affect simulator sickness to some users. The factor parallax, position, and height different effects are studied in this paper. The experimental results show the position and the height difference are important effects and they are independent from the content characters. The position effect shows the driver position suffers least simulator effect. Moreover, passenger in the left position has got less simulator sickness when comparing with the right position. Although, the passenger who taller than the driver suffer higher sickness and parallax 9.0 cm effect highest simulator sickness.
  Factor effects are analysed by principal component analysis to indicate the most important factor effect between parallax, position and height different factors. The highest rotated factor loadings in descending order are height difference, position, and parallax factor, respectively.

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  Adding edges to a network does not always improve the transfer/transport speed. Braess's paradox is a situation that is caused by an added edge which degrades the overall transfer time instead of improving it. As a result, removing the Braess's paradox causing edge will improve the overall transport time. In this paper, we propose an algorithm that pinpoints which edge is causing Braess's paradox if it is occurring. Consequently it allows us to prevent Braess's Paradox from occurring and to improve the total transportation time.

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