Capability Of Code Research Articles

Computational rheology with OpenFOAM® computational library

<h2>Abstract</h2> The current capabilities of numerical codes, which able to model very complex processes, and the existing powerful computational resources, clearly promote the employment of numerical modeling tools to assist design-related tasks. The Computational Rheology Group, from the Institute for Polymers and Composites (IPC) of the University of Minho (UMinho), has been developing and exploiting modeling codes for more than one decade, with a special focus on polymer processing applications. During the last 6 years, most of the numerical developments of the Computational Rheology Group were based on the OpenFOAM® computational library. This talk aims at providing an overview of the computational rheology-related work done at IPC/UMinho, in close cooperation with industry, and at illustrating the advantages of using the computational library OpenFOAM® for the development of new codes. The presentation will cover both the work done by the group to support the design of polymer processing tools and the development of new solvers in the OpenFOAM® computational library.

Realization of an Error-Correcting Surface Code with Superconducting Qubits.

Quantum error correction is a critical technique for transitioning from noisy intermediate-scale quantum devices to fully fledged quantum computers. The surface code, which has a high threshold error rate, is the leading quantum error correction code for two-dimensional grid architecture. So far, the repeated error correction capability of the surface code has not been realized experimentally. Here, we experimentally implement an error-correcting surface code, the distance-three surface code which consists of 17 qubits, on the Zuchongzhi 2.1 superconducting quantum processor. By executing several consecutive error correction cycles, the logical error can be significantly reduced after applying corrections, achieving the repeated error correction of surface code for the first time. This experiment represents a fully functional instance of an error-correcting surface code, providing a key step on the path towards scalable fault-tolerant quantum computing.

Accurate Modeling of Lyα Profiles and Their Impact on Photolysis of Terrestrial Planet Atmospheres

Accurately measuring and modeling the Lyα (Lyα; λ1215.67 Å) emission line from low-mass stars is vital for our ability to build predictive high energy stellar spectra, yet interstellar medium (ISM) absorption of this line typically prevents model-measurement comparisons. Lyα also controls the photodissociation of important molecules, like water and methane, in exoplanet atmospheres such that any photochemical models assessing potential biosignatures or atmospheric abundances require accurate Lyα host star flux estimates. Recent observations of three early M and K stars (K3, M0, M1) with exceptionally high radial velocities (>100 km s−1) reveal the intrinsic profiles of these types of stars as most of their Lyα flux is shifted away from the geocoronal line core and contamination from the ISM. These observations indicate that previous stellar spectra computed with the PHOENIX atmosphere code have underpredicted the core of Lyα in these types of stars. With these observations, we have been able to better understand the microphysics in the upper atmosphere and improve the predictive capabilities of the PHOENIX atmosphere code. Since these wavelengths drive the photolysis of key molecular species, we also present results analyzing the impact of the resulting changes to the synthetic stellar spectra on observable chemistry in terrestrial planet atmospheres.

Geometric graph-theoretic aspects of quantum stabilizer codes

We propose a systematic procedure for the construction of graphs associated with binary quantum stabilizer codes. The procedure is characterized by means of the following three step process. First, the stabilizer code is realized as a codeword-stabilized (CWS) quantum code. Second, the canonical form of the CWS code is determined and third, the input vertices are attached to the graphs. In order to verify the effectiveness of the procedure, we implement the Gottesman stabilizer code characterized by multi-qubit encoding operators for the resource-efficient error correction of arbitrary single-qubit errors. Finally, the error-correcting capabilities of the Gottesman eight-qubit quantum stabilizer code is verified in graph-theoretic terms as originally advocated by Schlingemann and Werner.

Error Detection and Correction for Golay Code &amp; Extended Golay Code using Cyclic Redundancy Check

In this paper certain optimization techniques are proposed to reduce the encoder and decoder computation time of cache memory that is affected by soft error and by implementing ECC such as cyclic and block codes. Error that is adjacent by a width of three and two bits are the prime concern of this thesis. Optimised Golay code (23, 12) and new block code size (32, 19) which is also optimised are presented. Nevertheless, cyclic code is efficient compared with block code however, the prime concern of the thesis is to address the triple and double adjacent errors which also includes single bit error, in this regard built-in capability of Golay code is optimised and used for comparison. The extended Golay code is implemented in term of number of slice, number of LUT and maximum combinational path delay compared with existing Golay code.

Robust image watermarking algorithm using chaotic sequences

This article presents a robust image watermarking scheme that provides high robustness and imperceptibility based on an innovative application of chaotic bits and error-correcting codes. The bits embedded in the image are the parity bits of an error-correcting code whose information sequence is formed by combining the watermark bits with chaotic bits generated from a secret key known to all legitimate users. Therefore, a part of the codeword is perfectly known to these users in the watermark extraction processing regardless of the strength of an attack. Thus, the error-correcting code capability is employed in recovering the watermark bits, improving the robustness of the method. The parity bits are embedded at specific frequencies of the discrete cosine transform and a parameter controls the compromise between robustness and imperceptibility. The proposed method is tested against several signal processing and geometric attacks, and comparison results reveal that it outperforms the existing schemes.

Scalable semantic-enhanced supervised hashing for cross-modal retrieval

Cross-modal retrieval is a classic scenario that can describe the same semantics from multiple angles and provide us with more abundant and diversified information ; thus, it has abundant applications in information retrieval, data mining, and machine learning. Generally, supervised information can enhance the ability to learn hash features, and obtain better retrieval accuracy than unsupervised methods. However, how to effectively solve the discrete binary constraint problem, and how to retain more semantic information in the process of hash learning, which constitute important parts of cross-modal retrieval, still have some challenges. To mitigate these problems, in this work, we propose a novel cross-modal hashing approach, called, scalable pairwise embedding constraint hashing (SPECH). The SPECH approach employs the loss of likelihood similarity technique using pairwise sample data to measure the semantic similarity of heterogeneous modal samples. In light of this, the SPECH approach can maximize the utilization of available data from heterogeneous modal samples for training models. In addition, we further enhance the discriminative capability of hash codes and reduce the intraclass differences in heterogeneous modal samples, by embedding the more discriminative semantic label attribute space regression into the to-be-learned process of hash codes. Comprehensive experiments on three benchmark datasets show that the proposed SPECH approach achieves significantly better retrieval accuracy and outperforms several state-of-the-art approaches on cross-modal retrieval applications.

Scattering-coded architectured boundary for computational sensing of elastic waves

Object localization through active elastic waves is a crucial technology but generally requires a transducer array with complex hardware. Although computational sensing can overcome the shortcomings of transducer array by merging artificially designed structures into the sensing process, coding spatial elastic waves for active object sensing is still a knowledge gap. Here, we propose a scattering-coded architectured boundary composed of randomly distributed scatterers for computational sensing of objects with a single transducer. The multiple scattering effects of the architectured boundary introduce complexity into scattered fields to achieve a highly uncorrelated scattering coding of Lamb waves, thereby eliminating the ambiguity of the object location information. We demonstrate that the object locations can be uniquely identified by using the scattering-coded architectured boundary. The proposed strategy opens avenues for artificially designed boundaries with the capability of information coding and identification, providing important applications in wave sensing such as human-machine interactions and structural monitoring. • An architectured boundary is proposed for object localization with a single transducer • Complex disturbances caused by multiple scattering enable spatial scattering coding • Object locations are identified by using a computational sensing algorithm • A type of touchscreen with an architectured boundary is designed for interactive input Jiang et al. propose a scattering-coded architectured boundary composed of randomly distributed scatterers for computational sensing of objects with a single transducer. This strategy provides avenues for artificially designed boundaries with the capability of information coding, boosting wave-sensing applications such as structural monitoring and human-machine interactions.

Hybrid-gyrokinetic simulations of low-n toroidal Alfvén eigenmodes using gKPSP

We report a benchmark study of toroidal Alfvén eigenmode (TAE) simulation using the hybrid-gyrokinetic code GyroKinetic Plasma Simulation Program (gKPSP). A simulation capability for energetic particles based on the gyrokinetic δf method has been newly implemented in the gKPSP code. Benchmark simulations have been performed in both circular and realistic tokamak geometries. Good agreement has been found with previously reported results, demonstrating the new capability of the gKPSP code. We have investigated the effects of the distribution function on TAE stability by examining both isotropic and anisotropic slowing-down distributions of energetic particles. The slowing-down distribution produces a higher linear growth rate than a Maxwellian distribution, while a growth rate scan with the anisotropy shows an opposite trend. This can be attributed to competition between Landau damping and the linear drive, which are correlated with the fraction of resonant passing particles and their distribution in phase space.

Half diagonal matrix codes for reliable embedded memories

Reliability of embedded memories is dependent on at-speed rated correction capability of error detection and correction codes. Many critical applications like medical databases, rocket launch details stored in memories require accurate data and which cause major human losses or economy losses even if a 1% of data is compromised. This paper focuses on developing improved reliable error detection and correction codes with minimum redundant bits and maximum code rate. The decoder uses the concept of Encoder Reuse Technique along with the Modulo-2 addition to calculate syndrome, error location and correction of data bits when data is read from memory. The codes are represented in verilog hardware description language and simulated in the Tool Xilinx ISE 14.5 for XC7Z020-1CLG484 FPGA. The codes are evaluated for their performance in terms of technology parameters like area, delay, power, power – delay product, etc. Also for other parameters like bit overhead, code rate, code efficiency, correction coverage, correction efficiency, etc and correction coverage per cost for combined evaluation. The implemented half diagonal code is more effective as compared to existing matrix codes, it reduces bit overhead at least by 5.5% to 46.96% and coding rate increased at least by 16.74% to 23.85%.

A coding layer robust reversible watermarking algorithm for digital image in multi-antenna system

Although existing robust reversible watermarking (RRW) schemes are robust to image processing attacks, they do not consider the effect of noise on the encoded digital images when they are transmitted in the wireless channel. In this paper, we propose a coding layer robust reversible watermarking (CL-RRW) algorithm for digital images in multi-antenna system. Through the specially designed preprocessing steps for the encoded carrier image and the embedding method of secret information, the scheme makes full use of the error correction capability of channel coding, and makes the impact of the embedding of secret information on the carrier approximate to natural noise. We analyse the proposed scheme based on multi-antenna systems and Rayleigh fading channels, which can simulate more realistic wireless communication scenarios. The analysis shows that in this scenario, the embedding capacity (EC) can reach the upper bound more quickly as the signal-to-noise ratio (SNR) increases. Within the deduced EC, the difference in peak signal-to-noise ratio (PSNR) between the original and stego images does not exceed 10%. Experimental results show that the proposed algorithm is entirely resistant to image processing attacks, while enabling the receiver to obtain high-quality carrier images and low bit error rate (BER) secret information.

Efficient d-dimensional molecular dynamics simulations for studies of the glass-jamming transition.

We develop an algorithm suitable for parallel molecular dynamics simulations in d spatial dimensions and describe its implementation in C++. All routines work in arbitrary d; the maximum simulated d is limited only by available computing resources. These routines include several that are particularly useful for studies of the glass-jamming transition, such as SWAP Monte Carlo and FIRE energy minimization. The scalings of simulation runtimes with the number of particles N and number of simulation threads n_{threads} are comparable to popular molecular dynamics codes such as LAMMPS. The efficient parallel implementation allows simulation of systems that are much larger than those employed in previous high-dimensional glass-transition studies. As a demonstration of the code's capabilities, we show that supercooled d=6 liquids can possess dynamics that are substantially more heterogeneous and experience a breakdown of the Stokes-Einstein relation that is substantially stronger than previously reported, owing at least in part to the much smaller system sizes employed in earlier simulations.

Performance of Teleportation-Based Error-Correction Circuits for Bosonic Codes with Noisy Measurements

Bosonic quantum error-correcting codes offer a viable direction towards reducing the hardware overhead required for fault-tolerant quantum information processing. A broad class of bosonic codes, namely rotation-symmetric codes, can be characterized by their phase-space rotation symmetry. However, their performance has been examined to date only within an idealistic noise model. Here, we further analyze the error-correction capabilities of rotation-symmetric codes using a teleportation-based error-correction circuit. To this end, we numerically compute the average gate fidelity, including measurement errors into the noise model of the data qubit. Focusing on physical measurement models, we assess the performance of heterodyne and adaptive homodyne detection in comparison to the previously studied canonical phase measurement. This setting allows us to shed light on the role of different currently available measurement schemes when decoding the encoded information. We find that with the currently achievable measurement efficiencies in microwave optics, bosonic rotation codes undergo a substantial decrease in their break-even potential. In addition, we perform a detailed analysis of Gottesman-Kitaev-Preskill (GKP) codes using a similar error-correction circuit that allows us to analyze the effect of realistic measurement models on different codes. In comparison to RSB codes, we find for GKP codes an even greater reduction in performance together with a vulnerability to photon-number dephasing. Our results show that highly efficient measurement protocols constitute a crucial building block towards error-corrected quantum information processing with bosonic continuous-variable systems.

Quadratic interpolation boosted black widow spider-inspired optimization algorithm with wavelet mutation

Meta-heuristic algorithms are effective in solving complex optimization problems with advantages of flexibility for coding, robustness and global optimization capability. An enhanced Black Widow Optimization called QIWBWO algorithm with three improvement strategies is proposed in this paper. At the beginning of search, the theory of good points set is used to obtain the better initial population, which helps the algorithm to quickly determine the correct search direction. Then, quadratic interpolation strategy is used to improve the solution accuracy and accelerate the convergence. Meanwhile, to avoid the algorithm falling into a local optimum, wavelet mutation is introduced to improve population diversity and helps the algorithm to search the global optimum rather than local optimums. The proposed BWO algorithm is compared with other different kinds of meta-heuristic algorithms on 25 traditional benchmark functions and CEC2017 competition suite. The statistical results show the improved BWO algorithm delivers better performance in accuracy, stability and convergence rate. Finally, QIWBWO also obtains the best results on four classical optimization problems in engineering application, which verifies its practicality and effectiveness. The source code of QIWBWO is publicly available in the supplementary material related to this article.

Numerical study of kerosene spray and combustion characteristics using an air-blast atomizer

In this study, a computational model for a cylindrical combustor with an air-blast atomizer was created to investigate the effect of changing air to liquid mass ratio (ALR) on spray characteristics without combustion and the effect of changing ALR on combustion characteristics under different swirl numbers with constant kerosene fuel mass flow rate using computational fluid dynamics (CFD) code. The study aim is to define the ALR at which the pollutants concentrations at combustion exhaust will be the least. Eight values of ALR were considered and these include 0.3, 0.5, 0.7, 0.9, 1.0, 1.2, 1.4 and 1.5. The cold spray characteristics including the number of droplets, Sauter Mean Diameter, droplets penetration length and droplets contours were obtained in addition to combustion characteristics that were studied by describing the reverse flow zone (RFZ) boundary, flow pathlines, temperatures maps, outlet temperatures at combustor exit and species concentrations. The results indicate that increasing ALR and consequently spray droplet diameter decrease does not always translate into superior emissions performance and it depends on several parameters including swirling intensity where the modernistic capabilities of CFD code including flow visualization and calculated recirculated mass flow ratio are used to justify the reasons behind this exceptional behavior. In addition, the results show that the spray Sauter Mean Diameter decreases by increasing ALR but the droplet diameter reduction effect was steeper at lower ALR than higher ones. The length of the RFZ is decreasing with the increase of ALR and shifts upstream closer to the combustor swirler. The recirculated flow mass ratio and the outlet average temperature are decreasing with the increase of ALR.

Code-to-code comparison and validation of the radiation-hydrodynamics capabilities of the FLASH code using a laboratory astrophysical jet

The potential for laser-produced plasmas to yield fundamental insights into high energy density physics (HEDP) and deliver other useful applications can sometimes be frustrated by uncertainties in modeling the properties and behavior of these plasmas using radiation-hydrodynamics codes. In an effort to overcome this and to corroborate the accuracy of the HEDP capabilities in the publicly available FLASH radiation-hydrodynamics code, we present detailed code-to-code comparisons between FLASH and the HYDRA code developed at Lawrence Livermore National Laboratory using previously published HYDRA simulations from Grava et al. [Phys. Rev. E 78, 016403 (2008)]. That study describes a laser experiment that produced a jet-like feature that the authors compare to astrophysical jets. Importantly, the Grava et al. [Phys. Rev. E 78, 016403 (2008)] experiment included detailed x-ray interferometric measurements of electron number densities and a time-integrated measurement of the soft x-ray spectrum. Despite markedly different methods for treating the computational mesh, and different equations of state and opacity models, the FLASH results resemble the results from HYDRA and, most importantly, the experimental measurements of electron density. Having validated the FLASH code in this way, we use the code to further investigate and understand the formation of the jet seen in the Grava et al. [Phys. Rev. E 78, 016403 (2008)] experiment and discuss its relation to the Wan et al. [Phys. Rev. E 55, 6293 (1997)] experiment at the NOVA laser.

RELAP5 application for water hammer analysis in different thermal-hydraulic systems

• Causes of water hammers: rapid valve operation, void-induced, condensation-induced. • RELAP5 code may represent water hammer due to valve operation and appearance of void. • The developed modelling recommendations are based on comparative analysis. • Water hammer in nuclear, fusion and district heating systems possible due to fast valve actions. • Integrity of pipelines in nuclear, fusion and district heating systems remain not violated. The water hammer phenomenon investigations employing RELAP5 code with one-dimensional two-fluid six-equation models of water and steam flow were performed and the main results shared in this paper. The capability of RELAP5 code to simulate transients leading strong pressure pulses was investigated employing the measurement results of three test facilities for different water hammer types: PPP at UMSICHT, CWHTF at FZR Dresden and PMK-2 at AEKI. Based on the benchmarking results the recommendations for the modelling of piping systems, which could be affected by different types of water hammer were developed and tested. The recommendations cover selection of thermal-hydraulic system conditions, parameters of modelling and RELAP5 code correlations. These recommendations have enabled to develop a detail RELAP5 models for the simulation of water hammer effects in further research works. The applications of RELAP5 code for water hammer analysis in different thermal-hydraulic systems (RBMK-1500 reactor main circulation loop, targets cooling/heating circuit in Wendelstein 7-X experimental stellarator facility and pipelines in district heating system) are presented in this paper. The performed analyses of transients demonstrated that the pressure pulsations could appear in all these systems as results of check valve closures. However, pressure surges are not so strong due to specific of such systems and integrity of pipelines remains not violated.

Bioinformation Systems with Detectors and Signal Coding Capabilities

Introduction. The integration of computer technologies into various fields of science allows the development of new methodologies, hybrid information systems with advanced capabilities, such as EcoIS bioinformation system for monitoring the environment with the use of biological data detectors.Problem Statement. The development of innovation bioinformation systems with biological data detectors is a very important task, as they have numerous advantages: allow rapid diagnostics and testing of chemicals in thefirst moments of their action, may be incorporated easily into electronic registration systems, may serve as elementary analytical units with data coding capabilities, etc.Purpose. The purpose of this research is to make a comprehensive analysis of different types of biological data detectors to develop a physical model of a biosensor capable of encoding signals and a bioinformation system with such detectors.Materials and Methods. The comparative analysis of information systems with functions of ecomonitoring and different types of biosensors have been used; the data are taken from electrophysiological experiments on registration of chemosensitive transmembrane electric currents in voltage clamp and patch clamp modes.Results. The physical model of biosensor has been developed and tested. The integration of the developed biosensors into the electronic bioinformation system by the example of EcoIS authors’ system has been demonstrated. Neuron-like biosensor has been considered an abstraction in the unity of its functions: signal receiver — filter — analyzer — encoder/decoder, where the input information is obtained in the form of chemical structures or electrical signals, after the conversion (recoding) of information it is registered as electrical signals with changed characteristics. The prospects for developing the cutting-edge methods for information protection in systems with biosensors have been shown. Conclusions. This development may be used for creating a bioinformation system for environmental moni toring with integrated biosensor system and data protection based on the principles and achievements of contemporary biophysics.

SPACE: 3D parallel solvers for Vlasov-Maxwell and Vlasov-Poisson equations for relativistic plasmas with atomic transformations

A parallel, relativistic, three-dimensional particle-in-cell code SPACE has been developed for the simulation of electromagnetic fields, relativistic particle beams, and plasmas. In addition to the standard second-order Particle-in-Cell (PIC) algorithm, SPACE includes efficient novel algorithms to resolve atomic physics processes such as multi-level ionization of plasma atoms, recombination, and electron attachment to dopants in dense neutral gases. SPACE also contains a highly adaptive particle-based method, called Adaptive Particle-in-Cloud (AP-Cloud), for solving the Vlasov-Poisson problems. It eliminates the traditional Cartesian mesh of PIC and replaces it with an adaptive octree data structure. The code's algorithms, structure, capabilities, parallelization strategy, and performance have been discussed. Typical examples of SPACE applications to accelerator science and engineering problems are described.

An Overview of the MPEG Standard for Storage and Transport of Visual Volumetric Video-Based Coding

The increasing popularity of virtual, augmented, and mixed reality (VR/AR/MR) applications is driving the media industry to explore the creation and delivery of new immersive experiences. One of the trends is volumetric video, which allows users to explore content unconstrained by the traditional two-dimensional window of director’s view.The ISO/IEC joint technical committee 1 subcommittee 29, better known as the Moving Pictures Experts Group (MPEG), has recently finalized a group of standards, under the umbrella of Visual Volumetric Video-based Coding (V3C). These standards aim to efficiently code, store, and transport immersive content with 6 degrees of freedom. The V3C family of standards currently consists of three documents: 1) ISO/IEC 23090-5 defines the generic concepts of volumetric video-based coding and its application to dynamic point cloud data; 2) ISO/IEC 23090-12 specifies another application that enables compression of volumetric video content captured by multiple cameras; and 3) ISO/IEC 23090-10 describes how to store and deliver V3C compressed volumetric video content. Each standard leverages the capabilities of traditional 2D video coding and delivery solutions, allowing for re-use of existing infrastructures which facilitates fast deployment of volumetric video.This article provides an overview of the generic concepts of V3C, as defined in ISO/IEC 23090-5. Furthermore, it describes V3C carriage related functionalities specified in ISO/IEC 23090-10 and offers best practices for the community with respect to storage and delivery of volumetric video.