Mixed Resolution Research Articles

Sampling Solvation Free Energy of Electrolytic Solvents with 3D2PT

Interactions between biomolecules and their surrounding solvation environment contribute significantly to their stability and to the driving forces for complex formation and conformational change. However, exploring the impact of solvation on these processes requires a thorough quantification of thermodynamic contributions to changes in the free energy of the system. Microscopic details available in atomistic molecular dynamics simulations allow for the extraction of solvation enthalpies from pair-wise additive protein-water and water-water interactions relative to the bulk solvent. The 3D-2PT method developed in the Heyden lab at Arizona State University complements this information with an analysis of hydration water entropies obtained from an analysis of intermolecular vibrations. Both the solvation enthalpy and entropy are analyzed on three-dimensional grids with 0.5-1.0 Å resolution allowing for direct thermodynamic insights into local hydration sites at the protein-water interface.Here, the original 3D-2PT approach is expanded to include contributions of electrolytes to the solvation enthalpy, entropy and free energy. This is achieved in a mixed resolution approach, which considers the drastic differences in concentration between water (∼55 M) and electrolytes (∼0.15 M) and resulting statistics for local environments. In addition to an analysis of water and ion vibrations in their local coordination environments, the new analysis distinguishes solute-water, solute-ion, water-water, ion-ion and water-ion interactions and their contributions to the solvation enthalpy.

No-Reference Quality Assessment of Stereoscopic Videos With Inter-Frame Cross on a Content-Rich Database

With the wide application of stereoscopic video technology, the quality of stereoscopic video has attracted people’s attention. Objective stereoscopic video quality assessment (SVQA) is highly challenging, but essential, particularly the no-reference (NR) SVQA method, where reference information is not needed and a large number of samples are required for training and testing sets. However, as far as we know, there are only a few samples in the established stereo video database, which is unsuitable for NR quality assessment and seriously hampers the development of NR-SVQA method. For these difficulties that we encountered, we carry out a comprehensive subjective evaluation of stereoscopic video quality in our newly established TJU-SVQA databases that contain various contents, mixed resolution coding and symmetrically/asymmetrically distorted stereoscopic videos. Furthermore, we propose a new inter-frame cross map to predict the objective quality scores. We compare and analyze the performance of several state-of-the-art 2D and 3D quality evaluation methods on our new databases. The experimental results on our established databases and a public database demonstrate that the proposed method can robustly predict the quality of stereoscopic videos.

Can pure polymer liquids be represented at two different resolutions simultaneously?

Given that the physical properties of polymeric liquids extend on a wide range of length scales, it is computationally convenient to represent them by coarse-grained descriptions at various granularities to investigate local and global properties simultaneously. We use the Integral Equation Coarse-Graining (IECG) theory for a mixture of two species with various resolutions representing polyethylene polymeric liquids and derive interacting potentials that ensure consistencies of relevant thermodynamical and structural properties. These properties are in agreement with the corresponding atomistic resolution description. The composition, temperature, and density dependences of such mixed resolution potentials are investigated numerically and analytically. In the limit of long polymer chains, where Markovian statistics is obeyed, the potentials are analytically solved and decay with characteristic scaling exponents that depend on the mixture composition and CG resolution of the two components. The implications of the effective IECG potentials are also discussed for multiresolution simulation approaches.

Ocean kinetic energy backscatter parametrizations on unstructured grids: Impact on mesoscale turbulence in a channel

We present a new energy backscatter parametrization for primitive equation ocean models at eddy-permitting resolution, specifically for unstructured grids. Traditional eddy parametrizations in terms of viscosity closures lead to excessive dissipation of kinetic energy when used with eddy-permitting meshes. Implemented into the FESOM2 ocean model, the backscatter parametrization leads to a more realistic total dissipation of kinetic energy. It maintains a reservoir of dissipated energy and reinjects this subgrid energy at larger scales at a controlled rate. The separation between dissipation and backscatter scales is achieved by using different-order differential operators and/or spatial smoothing. This ensures numerical model stability.We perform sensitivity studies with different choices of parameter settings and viscosity schemes in a configuration with a baroclinically unstable flow in a zonally reentrant channel with a horizontally uniform mesh. The best backscatter setup substantially improves eddy-permitting simulations at 1/4° and 1/6° resolution, bringing them close to a 1/12° eddy-resolving reference. Improvements are largest for levels of kinetic energy and variability in temperature and vertical velocity. A selected optimal default scheme is then tested in a mixed resolution setup – a channel with narrow transitions between an eddy-permitting and an eddy-resolving subdomain. The backscatter scheme is able to adapt dynamically to the different resolutions and moves the diagnostics closer to the high resolution reference throughout the domain.Our study is a first step toward using backscatter in global variable-mesh ocean models and suggests potential for substantial improvements of ocean mean state and variability at reduced computational cost.

Seasonal predictability of European summer climate re-assessed

We improve seasonal hindcast skill of European summer climate in an ensemble based coupled seasonal prediction system by selecting individual ensemble members based on their respective consistent chain of processes that describe a physical mechanism. This mechanism is associated with the second mode of seasonal climate variability in the North-Atlantic-European sector and is contrary to the summer North Atlantic Oscillation. We initially analyse the mechanism in the ERA-Interim reanalysis and then test the influence of the mechanism on European hindcast skill in an initialised coupled seasonal climate model. We show that the mechanism originates in the tropical North Atlantic in spring, where either warm or cold sea surface temperature anomalies (SSTs) are connected with the European climate by an upper-level wave-train. This wave-train is accompanied by a zonal pressure gradient, that in turn influences the climate over central Europe in the following summer. We analyse the seasonal summer hindcast skill in a mixed resolution hindcast ensemble simulation generated by MPI-ESM, with 30 members starting every year in May. While the mean over the full ensemble shows no seasonal hindcast skill in summer, we achieve significant hindcast skill through forming a new mean over subselected ensemble members. For this selection, we test every ensemble member for the proposed consistent chain of connections between the wave-train, the zonal pressure gradient and their impact on European summer temperatures, and find that the processes that describe the mechanism are not represented in every ensemble member. Due to its influence on European summer climate, we use the condition of the persistent spring SSTs to anticipate the phase of the mechanism in each considered year. We thus use statistical relations to select ensemble members generated by a dynamical prediction system. With this approach, we significantly enhance the seasonal hindcast skill and the reliability of the hindcasts in the North-Atlantic-European sector, especially in the areas where the mechanism is showing a prominent signal. Since we only use knowledge that would be available in a real forecast set-up, this approach can potentially be applied in operational ensemble prediction systems.

Hot Jupiter accretion: 3D MHD simulations of star–planet–wind interaction

We present 3D MHD simulations of the wind-wind interactions between a solar type star and a short period hot Jupiter exoplanet. This is the first such simulation in which the stellar surface evolution is studied in detail. In our simulations, a planetary outflow, based on models of FUV evaporation of the exoplanets upper atmosphere, results in the build-up of circumstellar and circumplanetary material which accretes onto the stellar surface in a form of coronal rain, in which the rain is HJ wind material falling onto the stellar surface. We have conducted a suite of mixed geometry high resolution simulations which characterise the behaviour of interacting stellar and planetary wind material for a representative HJ hosting system. Our results show that magnetic topology plays a central role in forming accretion streams between the star and HJ and that the nature of the accretion is variable both in location and in rate, with the final accretion point occurring at $\phi~=~227^{\circ}$ ahead of the sub-planetary point and $\theta~=~53^{\circ}$ below the orbital plain. The size of the accretion spot itself has been found to vary with a period of $67 \ \mathrm{ks}$. Within the accretion spot, there is a small decrease in temperature accompanied by an increase in density compared with ambient surface conditions. We also demonstrate that magnetic fields cannot be ignored as accretion is highly dependent upon the magnetic topology of both the HJ and the host. We characterise this behaviour as Star Planet Wind Interaction (SPWI)

Two-Layered Mechanism of Online Unmanned Aerial Vehicles Conflict Detection and Resolution

This paper presents a study on short-term cooperative conflict detection and resolution (CDR) of unmanned aerial vehicles (UAVs). A two-layered CDR mechanism is proposed, which aims at guaranteeing safe separation, minimizing the overall cost of UAVs, and improving computational efficiency. In the first layer, the information from the environment is processed. In the second layer, conflicts among UAVs are resolved by applying the local centralized optimization method, with consideration given to the dynamic constraints of UAVs. This paper studies the safe separation constraints of pairwise conflicts in virtue of a geometry-based method. A heading change and speed change mixed conflict resolution approach is applied. To meet with the online planning requirements, the vectorized stochastic parallel gradient descent-based method is proposed to find the local optimal heading change solutions. The linear safe separation constraints on speeds are derived. A periodicity feature-based method is used to depart the feasible sub-regions for each pairwise conflict. A mixed integer linear programming model is established to find the optimal speed change solutions. The experiments results show that the proposed heading change algorithm could greatly reduce the summation of additional flight distances of UAVs, and influences on air traffic, compared with other short-term algorithms; the computational efficiency of this algorithm satisfies the online planning requirement. Comparing with the existing algorithm, our speed change algorithm reduces the number of feasible sub-regions to $2^{n_{c} }$ times lower, where $n_{c}$ is the number of pairwise conflict, and therefore, it reduces computation time dramatically.

Mixed-resolution HEVC based multiview video codec for low bitrate transmission

There has been increasing demand for multiview video transmission over band limited channel over past years and various techniques have been proposed to fulfil this need. In this paper, a High Efficiency Video Codec (HEVC) based spatial resolution scaling type of mixed resolution coding model, MRHEVC-MVC, for frame interleaved multiview videos is presented. However, enabling the HEVC to encode video with different frame resolutions is a challenge due to the coding tree partitioning used by the codec. This has been overcome by super-imposing the low resolution replica of each full resolution frame on their respective decoded picture buffer and setting the remaining space of the frame buffer to zero. The codec’s reference frames structure is designed to efficiently encode frame interleaved multiview videos using a HEVC based mixed resolution codec. The proposed MRHEVC-MVC codec has been tested against the standard multiview extension of high efficiency video codec (MV-HEVC) for “Balloon”, “Newspaper1”, “Undo_Dancer”, “Kendo” and ““Poznan_Street” standard multiview video sequences. Results show that the proposed codec gives significantly higher coding performance to that of the MV-HEVC codec at low bitrate both subjectively and objectively.

Sequential experimentation approach for robust design

AbstractThe Taguchi approach for robust design has been a common practice in industrial experimentation for many years. However, these designs possess serious disadvantages such as the inability to estimate control × control interactions. In this article, we propose the application of the R3 algorithm as an augmentation tool for Taguchi experiments. The augmented Taguchi designs were compared with its competitors, mixed resolution designs, and D‐optimal augmentation, using performance indicators. The results showed that Taguchi designs augmented with the R3 algorithm are capable of estimating control × control interactions, possess similar values for performance indicators when compared with other techniques, and in most cases require less runs.

Multiobjective Design Optimization Using Dual-Level Response Surface Methodology and Booth's Algorithm for Permanent Magnet Synchronous Generators

This paper studies a dual-level response surface methodology (DRSM) coupled with Booth's algorithm using a simulated annealing (BA-SA) method as a multiobjective technique for parametric modeling and machine design optimization for the first time. The aim of the research is for power maximization and cost of manufacture minimization resulting in a highly optimized wind generator to improve small power generation performance. The DRSM is employed to determine the best set of design parameters for power maximization in a surface-mounted permanent magnet synchronous generator with an exterior-rotor topology. Additionally, the BA-SA method is investigated to minimize material cost while keeping the volume constant. DRSM by different design functions including mixed resolution robust design, full factorial design, central composite design, and box-behnken design are applied to optimize the power performance resulting in very small errors. An analysis of the variance via multilevel RSM plots is used to check the adequacy of fit in the design region and determines the parameter settings to manufacture a high-quality wind generator. The analytical and numerical calculations have been experimentally verified and have successfully validated the theoretical and multiobjective optimization design methods presented.

Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM).

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of "bottom-up" coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.

La Motivación en la Resolución de Problemas Aritmético-algebraicos. Un Estudio con Alumnado de Educación Secundaria

Introducción. La motivación constituye un factor importante en el aprendizaje de las matemáticas. Dentro de este ámbito educativo, la resolución de problemas ocupa un lugar central en la mayoría de currículos de matemáticas en Educación Secundaria. El objetivo de esta investigación es detectar las diferencias en motivación en función de las estrategias empleadas para la resolución de problemas aritmético-algebraicos.Método. Se han analizado los procedimientos de resolución de tres problemas verbales aritmético-algebraicos y se han recopilado datos sobre la motivación mediante un cuestionario basado en el modelo de expectativa-valor de Eccles y sus colaboradores adaptado para la aplicación en el aprendizaje de las matemáticas. La muestra está compuesta por 598 estudiantes de 2º, 3º y 4º de Educación Secundaria Obligatoria (ESO) de la Comunidad Autónoma Vasca.Resultados. Los resultados obtenidos indican que el grupo de alumnos con perfil de resolución algebraico obtiene puntuaciones superiores tanto en valor de la tarea como en la autoeficacia percibida. Además, el grupo de resolución sin perfil definido declara que el estudio de las matemáticas supone una mayor pérdida de oportunidades para realizar otras actividades.Discusión. Por una parte, el alumnado que resuelve los problemas algebraicamente muestra una motivación superior al grupo que alterna el álgebra y la aritmética como estrategias de resolución; por tanto, parece ser que la supuesta flexibilidad en la resolución implica menor motivación. Por otra parte, se discute la baja motivación del alumnado sin perfil de resolución definido en relación a su bajo rendimiento.

A New Mixed All-Atom/Coarse-Grained Model: Application to Melittin Aggregation in Aqueous Solution.

We introduce a new mixed resolution, all-atom/coarse-grained approach (AACG), for modeling peptides in aqueous solution and apply it to characterizing the aggregation of melittin. All of the atoms in peptidic components are represented, while a single site is used for each water molecule. With the full flexibility of the peptide retained, our AACG method achieves speedups by a factor of 3–4 for CPU time reduction and another factor of roughly 7 for diffusion. An Ewald treatment permits the inclusion of long-range electrostatic interactions. These characteristics fit well with the requirements for studying peptide association and aggregation, where the system sizes and time scales require considerable computational resources with all-atom models. In particular, AACG is well suited for biologics since changes in peptide shape and long-range electrostatics may play an important role. The application of AACG to melittin, a 26-residue peptide with a well-known propensity to aggregate in solution, serves as an initial demonstration of this technology for studying peptide aggregation. We observed the formation of melittin aggregates during our simulations and characterized the time-evolution of aggregate size distribution, buried surface areas, and residue contacts. Key interactions including π-cation and π-stacking involving TRP19 were also examined. Our AACG simulations demonstrated a clear salt effect and a moderate temperature effect on aggregation and support the molten globule model of melittin aggregates. As a showcase, this work illustrates the useful role for AACG in investigations of peptide aggregation and its potential to guide formulation and design of biologics.

Stereoscopic Image Super-Resolution Method with View Incorporation and Convolutional Neural Networks

Super-resolution (SR) plays an important role in the processing and display of mixed-resolution (MR) stereoscopic images. Therefore, a stereoscopic image SR method based on view incorporation and convolutional neural networks (CNN) is proposed. For a given MR stereoscopic image, the left view of which is observed in full resolution, while the right view is viewed in low resolution, the SR method is implemented in two stages. In the first stage, a view difference image is defined to represent the correlation between views. It is estimated by using the full-resolution left view and the interpolated right view as input to the modified CNN. Accordingly, a high-precision view difference image is obtained. In the second stage, to incorporate the estimated right view in the first stage, a global reconstruction constraint is presented to make the estimated right view consistent with the low-resolution right view in terms of the MR stereoscopic image observation model. Experimental results demonstrated that, compared with the SR convolutional neural network (SRCNN) method and depth map based SR method, the proposed method improved the reconstructed right view quality by 0.54 dB and 1.14 dB, respectively, in the Peak Signal to Noise Ratio (PSNR), and subjective evaluation also implied that the proposed method produced better reconstructed stereoscopic images.

P‐70: Single Array Nozzle Source Method for Homogeneous Mixed Organic Thin Film and Low Mask Shadow in 6GH AMOLED Mass Production

We have developed Single Array Nozzle source (SAN source) organic thin film deposition method for 6G half size AMOLED mass production. The special feature of SAN source set is all of nozzles are arranged in one single line even if when we make 3 material mixed thin film. And the distance within each edge nozzle of SAN source is shorter than substrate size. We expect than SAN source set can improve homogeneity of mixed thin film and resolution of AMOLED pixel.

Studying Peptide Aggregation using Mixed All-Atom/Coarse Grain Molecular Dynamics Simulations

Peptide-peptide and peptide-excipient interactions need to be taken into account in biologics formulations. With the desire to formulate at very high peptide concentrations to improve patient experience and compliance, peptide-peptide interactions can lead to very high viscosity, denaturation, aggregation and precipitation. These problematic behaviors can complicate and slow down drug development, sometimes forcing compromises on target characteristics for the drug. We are exploring the use of molecular dynamics simulations to provide a molecular level understanding of peptide association. Our mixed all-atom/coarse grain model represents the protein using an all-atom representation with full flexibility while using a simplified coarse grain model for the environment. This approach permits a modest increase in system size and a significant increase in simulation speed relative to all-atom simulations while retaining the ability to study conformational changes of peptides in response to their environment. Such mixed resolution modeling approaches seem ideally suited to studying peptide-peptide association. We present results from a study of the aggregation of melittin, the predominant peptidic component of bee venom, to illustrate the potential for this approach. This approach yields the expected variation of aggregate size with the introduction of salt and provides residue level information. These results suggest that this model should also be useful for studying excipient effects in peptidic solutions.

Efficient multiple-example based super-resolution for symmetric mixed resolution stereoscopic video coding

In this paper, we first propose a new symmetric mixed resolution stereoscopic video coding (SMRSVC) model which can provide clear bitrate-reduction and visual merits. Based on the newly proposed SMRSVC model, we then propose a quality-efficient multiple-example based super-resolution method. In the proposed super-resolution method, the four block examples selected from the forward and backward key-frames, the reference super-resolved frame, and the interview super-resolved frame are referred so as to effectively fuse the high frequency component of the super-resolved current block of the downsampled non-key-frame, and then an enhanced super-resolved non-key-frame is followed. Based on six test stereoscopic video sequences, the experimental results demonstrate that besides the bitrate-saving effect, the proposed super-resolution method for the proposed SMRSVC model also has better quality performance in terms of six well-known quality metrics when compared with several state-of-the-art methods for the previous asymmetric resolution stereoscopic video coding model and the SMRSVC model.

Multiview video plus depth transmission via virtual-view-assisted complementary down/upsampling.

Multiview video plus depth is a popular 3D video format which can provide viewers a vivid 3D feeling. However, its requirements in terms of computational complexity and transmission bandwidth are more than that of conventional 2D video. To mitigate these limitations, some works have proposed to reduce the amount of transmitted data by adopting different resolutions for different views, and consequently, the transmitted video is called mixed resolution video. In order to further reduce the transmitted data and maintain good quality at the decoder side; in this paper, we propose a down/upsampling algorithm for 3D multiview video which systematically takes into account the video encoder and decoder. At the encoder side, the rows of the two adjacent views are downsampled following an interlacing and complementary fashion, whereas, at the decoder side, the discarded pixels are recovered by fusing the virtual view pixels with the directional interpolated pixels from the complementary downsampled views. Moreover, the patterns of the texture surrounding the discarded pixels are used to aid the data fusion, so as to enhance edges recovery. Meanwhile, with the assistance of virtual views, at the decoder side, the proposed approach can effectively recover the discarded high-frequency details. The experimental results demonstrate the superior performance of the proposed framework.

A method to reduce the complexity of conditional replenishment algorithm for hybrid 3DTV with mixed resolution

SC-MMH (Service Compatible 3DTV using Main and Mobile Hybrid) is a kind of hybrid 3DTV system where the resolutions of stereoscopic views are not identical and has become one of ATSC standards for terrestrial 3DTV. And CRA (Conditional Replenishment Algorithm) has been proposed to enhance the visual quality of this asymmetrical hybrid 3DTV with mixed resolution. CRA uses a variable-sized square block as a PU (Processing Unit) and the quad-tree is employed to represent the overall hierarchical structure. The largest and smallest sizes of PU of quad-tree affect the RD (Rate-Distortion) performance as well as the computational complexity of CRA. In this paper, we examine the effect of quad-tree levels on the BD-PSNR and the processing time. And we suggest the proper set of top and bottom levels which reduces the complexity of CRA with a negligible degradation of quality. Simulation for the stereoscopic sequences of HD resolution showed that the processing time of CRA can be considerably reduced to 70 % but the decrease of BD-PSNR is only 0.02 dB by employing of the combination of (7, 2) levels instead of conventional combination of (8, 0) levels. And the processing time could be more reduced to 60 % for UHD sequences when we used the combination of (7, 3) levels.

Molecular Simulation of Lipids and Water: Atomistic, Coarse-Grained, and Mixed Resolutions

Lipids and water are fundamental ingredients of living matter. Lipids form membranes which are employed by living organisms to enclose cells and organelles, transmit information, control molecular transport, and store energy. Water is the universal biological solvent. This presentation will focus on the investigation of lipid and water systems using different molecular dynamics simulation approaches. We will show results from all-atom simulations of mixed bilayers composed of lamellar and nonlamellar lipids. In particular, a quantitative characterisation has been obtained of the internal distributions (profiles) of lateral pressure, electric field, and dipole potential. These properties, very difficult to measure experimentally, are thought to play key roles in many membrane phenomena, including nonspecific lipid-mediated mechanisms of protein regulation. We will also describe the development of coarse-grained models, that are simplified representations in which entire groups of several nearby atoms are reduced to single particles. In particular, we will present recent results on the ELBA water model, where a water molecule is reduced to a single sphere embedded with a point dipole [1,2]. The ELBA model is remarkably accurate, and can be combined directly with atomistic force fields in mixed resolution systems [3]; however, recent results also highlight a number of issues in relation to ionic screening and phase behavior. Finally, we will report on ongoing efforts to develop a new “ultra coarse-grained” model for lipids and water, aimed at further increasing computational efficiency while retaining only the essential underlying physics.[1] M. Orsi, Mol. Phys. (2014), 112, 1566-1576.[2] W. Ding, M. Palaiokostas, M. Orsi, Mol. Simulat. (2015), http://dx.doi.org/10.1080/08927022.2015.1047367.[3] M. Orsi, W. Ding, M. Palaiokostas, J. Chem. Theory Comput. (2014), 10, 4684-4693.