Accurate Reproduction Research Articles

Studies on the motion and radiation of interior plasmas in gas-filled hohlraums with different laser entrance hole sizes

An experiment on 100 kJ laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums. These hohlraums are designed to possess one open end and one laser entrance hole (LEH) with different diameters, which would or not result in the blocking of the LEH. An x-ray streak camera that is set at 16 degrees with respect to the hohlraum axis is applied to acquire the time-resolved x-ray images from the open end. Based on the images, we can study the evolutions of the wall plasma, corona bubble plasma and LEH plasma simultaneously through an equivalent view field of hohlraum interior. Multi-group flat response x-ray detectors are applied to measure the x-ray fluxes. In order to understand these characteristics, our two-dimensional radiation hydrodynamic code is used to simulate the experimental results. For the accuracy of reproduction, dielectronic recombination and two parameter corrections are applied in our code. Based on the comparison between experiments and simulations, we quantitatively understand the blocking process of LEH and the motion effects of other plasmas. The calibrated code is beneficial to design the gas-filled hohlraum in a nearby parameter space, especially the limit size of LEH.

High-fidelity color characterization in virtual reality across head mounted displays, game engines, and materials.

We present a comprehensive colorimetric analysis of three head mounted displays (HMDs) - HTC Vive Pro Eye, Pimax 8K X DMAS, and Varjo Aero - focusing on their color calibration and uniformity across different game engines (Unity and Unreal) and for different materials/shaders. We developed a robust methodology combining hardware and software tools, including spectroradiometry and imaging colorimetry, to characterize and calibrate these HMDs for accurate color reproduction. The study showcases substantial advancements in colorimetric accuracy, with a reduction in the average deltaE00 of 90% or more across all tested HMDs and conditions. This level of color reproduction quality is below human discrimination thresholds, ensuring that any color inaccuracies remain imperceptible to the human eye. We also identified key areas for improvement, particularly in display uniformity, which could impact peripheral color reproduction. By making our tools and code publicly available, this study aims to facilitate future research and development in virtual reality (VR) technology, emphasizing the importance of color fidelity in virtual environments. The new insight enabled by our work is the extension and application of a traditional calibration method to currently available HMDs.

Frost heave of subgrade soil under complex traffic loads: Test system and experiments

Soil moisture freezing in cold climates leads to frost heave, a phenomenon influenced by soil texture, temperature, moisture levels, and applied loads. This investigation explores frost heave characteristics of subgrade soil under traffic-induced cyclic stresses, including cyclic compressive stress and alternating horizontal cyclic shear stress. A new frost heave test system was developed, featuring advanced temperature control and accurate loading path reproduction. Comprehensive frost heave experiments were performed to examine the frost heave process under various cyclic stress circumstances. Results indicate that cyclic stresses intensify in-situ frost heave of soil, with horizontal cyclic shear stress having a more significant promoting effect than vertical cyclic stress. The combination of vertical cyclic stress and horizontal cyclic shear stress leads to an increase in segregated frost heave. Moreover, vertical cyclic stress amplifies water absorption during soil frost heave. Total vertical deformation encompasses frost deformation in the frozen zone and consolidation in the unfrozen zone. Vertical cyclic stress may inhibit segregated ice lens formation and encourage consolidation in the unfrozen zone, thereby impeding vertical deformation. The simultaneous application of vertical cyclic stress and horizontal cyclic shear stress results in more intense ice segregation and moisture accumulation near the stable frost front.

Intellectual functionality of speech in children of older preschool age with logopathology

Background. The purpose of this study is to identify the current state of intellectual functioning, which affects the speech readiness to study at school, of older preschool children with logopathology. The study included 607 older preschool children (5–6 years old), 250 with normotypical psychophysical development and 357 with speech disorders (dyslalia, stuttering, rhinolalia, dysarthria). Materials and methods. To evaluate the intellectual functioning of older preschool children with logopathology, methods were developed aimed at studying visual-motor coordination, auditory-verbal memory, verbal-spatial representation, verbal-logical thinking, verbal attention. Results. The results of the experimental study give a clear idea that there are significant differences in the formation of intellectual functionality between children with logopathology and those with normotypical psychophysical development. Older preschool children with speech disorders had low ability to copy graphic images, violations of independent control and planning their own activities, problems with the consistent reproduction of words, the volume of memorization, the strength of retention of stimuli, the speed and accuracy of reproduction of speech information, the difficulties understanding spatial relations in the addressed and own speech; verbal and logical skills are formed heterogeneously. Some preschoolers with logopatho­logy can classify objects by features, generalize them, understand the figurative meaning of words and the content of texts. Others experience certain difficulties and make many mistakes; their verbal attention is not sufficiently developed, which prevents children from perceiving educational material. Conclusions. Accordingly, low indicators of visual-motor coordination, auditory-verbal memory, verbal-spatial representation, verbal-logical thinking, verbal attention in older preschool children with speech disorders indicate insufficiently formed intellectual functionality. This will affect their speaking readiness and learning the curriculum at school.

Applications of forensic anthropology methodology: accuracy of virtual face reproductions performed on the Tenchini collection.

Facial reproduction validation uses the methodology typical of forensic anthropology to confirm the accuracy of three-dimensional reproductions of faces. Achieving high accuracy in virtual facial reproductions is still under study. In the present paper, the Tenchini collection, which contains wax reproductions of prisoners' faces and their skulls, was used. By creating facial reproductions on skulls from this collection, the result was compared with the real face of the person to whom the skull belongs. The three-dimensional volume of each examined skull of Tenchini collection was acquired via CT scan and photogrammetry. Subsequently, the virtual reproduction of each skull was processed using three-dimensional graphics software (ZBrush, Pixologic®). The morphological comparison parameters used in the field of personal identification by forensic anthropology were used. The blind procedure required the operator to see the mask subsequent to the facial reproduction phase, so that the facial reproduction cannot exploit the information that knowledge of the mask would have produced. The parameters used in the study of facial reproductions have shown discrepancies between the characteristics of the masks and the facial reproductions, partly expected because due to the lack of soft tissue on the skull. However, a high degree of accuracy in the facial reproductions performed due to the applied methodology was documented. The present study allowed us to observe how these parameters can be useful to study the accuracy of facial reproduction and identify what difficulties are encountered in producing a result close to the real appearance.

Replicating outdoor environments using VR and ambisonics: a methodology for accurate audio-visual recording, processing and reproduction

This paper introduces a methodology tailored to capture, post-process, and replicate audio-visual data of outdoor environments (urban or natural) for VR experiments carried out within a controlled laboratory environment. The methodology consists of 360∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ$$\\end{document} video and higher order ambisonic (HOA) field recordings and subsequent calibrated spatial sound reproduction with a spherical loudspeaker array and video played back via a head-mounted display using a game engine and a graphical user interface for a perceptual experimental questionnaire. Attention was given to the equalisation and calibration of the ambisonic microphone and to the design of different ambisonic decoders. A listening experiment was conducted to evaluate four different decoders (one 2D first-order ambisonic decoder and three 3D third-order decoders) by asking participants to rate the relative (perceived) realism of recorded outdoor soundscapes reproduced with these decoders. The results showed that the third-order decoders were ranked as more realistic.

Role of the left posterior middle temporal gyrus in shape recognition and its reconstruction during drawing: A study combining transcranial magnetic stimulation and functional near infrared spectroscopy.

There are numerous reports of enhanced or emerged visual arts abilities in patients with semantic impairment. These reports led to the theory that a loss of function on the language side of the brain can result in changes of ability to draw and/or to paint. Further, the left posterior middle temporal gyrus (l-pMTG) has been revealed to contribute to the higher control semantic mechanisms with objects recognition and integration of visual information, within a widely distributed network of the left hemisphere. Nevertheless, the theory has not been fully studied in neural bases. The aim of this study is to examine role of the l-pMTG on shape recognition and its reconstruction within drawing behavior, by using a combining method of the repetitive transcranial magnetic stimulation (rTMS) and functional near-infrared spectroscopy (fNIRS). Eighteen healthy participants received a low frequency inhibitory rTMS to their l-pMTG during the drawing task of the Benton Visual Retention Test (BVRT). There was a significant decrease of the mean accuracy of reproductions in the Complex designs of the BVRT, compared to the Simple and Medium designs. The fNIRS data showed strong negative correlations with the results of the BVRT. Though our hypothesis had a contradiction that rTMS would have inhibited the brain activity in the stimulated site, the results suggest that shape recognition and its reconstruction such as the BVRT require neural activations of the l-TL as well as that of the l-pMTG.

Effect of the loading-rate and stress state on the constitutive modelling and fracture of 2205 Duplex stainless steel

Shear cutting is a high-speed forming process where material separation is involved. The nature of the process leads to high strain rates and temperatures on the sheared zone of the material subjected to the operation. In this work, the mechanical behavior in terms of flow stress, plastic deformation and fracture of a 2205 Duplex stainless steel sheet is determined. Uniaxial tension, uniaxial compression, stack compression, plane strain tension and simple shear tests at different angles with respect to the rolling direction of the metal sheet are performed to determine the anisotropic behavior of the material. Strain rate and temperature dependence of the flow stress and the plastic behavior of the material is determined through notched tensile tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s-1, 10 s-1 and >100 s-1). Finally, fracture behavior under various stress states is determined through notched tensile, central hole, in-plane shear and plane strain tests. The temperature and strain rate dependence of the fracture behavior is determined through notched tensile, in-plane shear and plane strain tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s-1, 10 s-1 and >100 s-1). The anisotropic behavior and work hardening of the material are modelled by the Hill48 yield function and Swift-Hockett-Sherby hardening law, respectively. Among the two ductile fracture models tested, Hosford-Coulomb model showed the best agreement and is therefore used to account for the temperature and strain rate effects on the fracture behavior. By combining these three models, an accurate reproduction of the mechanical behavior of the 2205 Duplex stainless steel sheet is achieved.

Three-Dimensional Printed Attachments: Analysis of Reproduction Accuracy Compared to Traditional Attachments

Background: The aim of this study was to propose a new 3D printing method for attachment production and compare the reproduction accuracy of traditional attachments with the proposed 3D-printed attachments. Methods: A standardized 3D model attachment was created with the dimensions of 3, 2, and 2 mm for the apico-coronal, mesio-distal, and vestibulo-lingual dimensions, respectively. A 3D ideal model of the maxillary arch was used to apply four standardized attachments on the vestibular surface of selected teeth. The obtained model with placed attachments was used to reproduce composite attachments via the conventional method. A transfer template was used to bond with the flow composite resin 3D-printed attachment on a new arch model without attachments. The models with traditional attachments and 3D-printed attachments were scanned and overlapped with the original CAD model with attachments. To assess the attachment precision, vertical and horizontal cutting planes were used on the overlapped models. The outcome selection focused on puff analysis (excess composite material evaluation) and shape analysis (attachment accuracy evaluation). Results: The results indicated that the 3D-printed attachments showed significant differences (p < 0.05) compared to the traditional attachments. The descriptive statistics showed the higher discrepancies compared to the CAD model of the traditionally created attachments in the shape (0.85 mm) and puff dimension (1.02 mm). Conclusion: Custom 3D-printed attachment production is an effective method for achieving greater attachment precision.

Thermodynamic assessment of the phase diagrams of calcite and CaO–CaCO3 system

The study of phase equilibria in the Ca-C-O system is complicated by the decomposition of one of the intermediate compounds, calcite. Experimental studies present an ambiguous interpretation of the results, which contain conflicting information about the phase diagrams of calcite and the CaO–CaCO3 system at pressures up to 100 MPa. Thermodynamic modelling has been used in this study for the determination of phase equilibria in these systems. Using reliable experimental phase diagram data, the thermodynamic properties of calcite and CaCO3(liq) were corrected to take into account the pressure influence. This resulted in an accurate reproduction of the experimental data on calcite phase equilibria and made it possible to construct a model of the CaO–CaCO3 system phase diagram taking into account the calcite decomposition. It will allow to further modelling of more complex processes involving calcite in the pressures range up to 30 MPa and temperatures up to 1800 K.

Estimation of color reproduction accuracy using a tunable source based on an acoustic-optical tunable filter

Estimation of color reproduction accuracy using a tunable source based on an acoustic-optical tunable filter

Color arrestor pixels for high-fidelity, high-sensitivity imaging sensors

Abstract Silicon is the dominant material in complementary metal-oxide-semiconductor (CMOS) imaging devices because of its outstanding electrical and optical properties, well-established fabrication methods, and abundance in nature. However, with the ongoing trend toward electronic miniaturization, which demands smaller pixel sizes in CMOS image sensors, issues, such as crosstalk and reduced optical efficiency, have become critical. These problems stem from the intrinsic properties of Si, particularly its low absorption in the long wavelength range of the visible spectrum, which makes it difficult to devise effective solutions unless the material itself is changed. Recent advances in optical metasurfaces have offered new possibilities for solving these problems. In this study, we propose color arrestor pixels (CAPs) as a new class of color image sensors whose composite spectral responses directly mimic those of the human eye. The key idea is to employ linearly independent combinations of standardized color matching functions. These new basis functions allow our device to reproduce colors more accurately than the currently available image sensors with red-green-blue filters or other metasurface-based sensors, demonstrating an average CIEDE2000 color difference value of only 1.79 when evaluating 24 colors from the Gretag-Macbeth chart under standard illuminant D65. Owing to their high fidelity to the human eye response, CAPs consistently exhibit exceptional color reproduction accuracy under various spectral illumination compositions. With a small footprint of 860 nm height and 221 nm full-color pixel pitch, the CAPs demonstrated high absorption efficiencies of 79 %, 81 %, and 63 % at wavelengths of 452 nm, 544 nm, and 603 nm, respectively, and good angular tolerance. With such a high density of pixels efficiently capturing accurate colors, CAPs present a new direction for optical image sensor research and their applications.

Non-parametric Gaussian process movement primitive with via-point constraint for effective and safe robot skill learning

Learning from demonstration (LFD) algorithms has been proven to be an effective way to encode basic human skills, such as probabilistic movement primitives (ProMPs). However, such algorithms are based on parametric methods, which means that more effort is required to expand to multi-dimensional and high reproduction accuracy. In this article, a novel non-parametric LFD algorithm is proposed, named Gaussian process movement primitive based on Gaussian mixture regression (GPGR), which has lower computational complexity and high accuracy. We encapsulate the variability of the demonstration set into the prior of Gaussian processes and propose a necessary and sufficient condition to ensure that the generated trajectory can pass the expected via point with 100% probability, which is different from existing ProMPs and their variants. In addition, we propose a novel trajectory obstacle avoidance method. The method allows efficient and safe robot obstacle avoidance by solving for a small number of via points. The effectiveness of the algorithm is validated through a series of experiments on the LASA dataset and the Franka Emika Panda robot.

Phantom Illusion Based Vibrotactile Rendering of Affective Touch Patterns.

Physically accurate (authentic) reproduction of affective touch patterns on the forearm is limited by actuator technology. However, in most VR applications a direct comparison with actual touch is not possible. Here, the plausibility is only compared to the user's expectation. Focusing on the approach of plausible instead of authentic touch reproduction enables new rendering techniques, like the utilization of the phantom illusion to create the sensation of moving vibrations. Following this idea, a haptic armband array (4x2 vibrational actuators) was built to investigate the possibilities of recreating plausible affective touch patterns with vibration. The novel aspect of this work is the approach of touch reproduction with a parameterized rendering strategy, enabling the integration in VR. A first user study evaluates suitable parameter ranges for vibrational touch rendering. Duration of vibration and signal shape influence plausibility the most. A second user study found high plausibility ratings in a multimodal scenario and confirmed the expressiveness of the system. Rendering device and strategy are suitable for a various stroking patterns and applicable for emerging research on social affective touch reproduction.

Побудова твердотілої моделі історичного об’єкту: на прикладі форту «Марушка Ліс»

Purpose of this work is to use terrestrial laser scanning for analysis and construction of a digital model of the fort “Marushka Lis” focusing on the process of data collection, processing, and their further use, particularly for web mapping of post-military sites. In the modern world, the preservation and restoration of historical structures is an important task that requires the application of advanced technologies. Methodology. Terrestrial laser scanning serves as an indispensable tool in this process, providing accurate and detailed spatial data. A technological scheme for creating a digital model of a historical object has been proposed. The study of historical objects using various methods of information collection was considered, namely: topographic surveying, terrestrial digital photogrammetry, terrestrial laser scanning, ground-penetrating radar studies, tachymetric surveying, GNSS. The methodology for creating a digital model of a historical object and the presented technological scheme, which includes data collection, processing of the obtained results, and output data, are described. Results. A comprehensive approach was applied to create the model, which included studying the history of the object, terrestrial laser scanning, terrestrial digital photogrammetry, and conducting geodetic measurements. A key aspect was the accurate and detailed reproduction of all architectural and structural elements of the fort. The use of software such as Leica Cyclone REGISTER 360, Autodesk ReCap, and Autodesk Revit allowed the integration of collected data into one accurate and detailed model. The sequential execution of work according to the proposed methodology enabled the creation of a digital model of the fort “Marushka Lis.” Scientific novelty and practical significance. The scientific novelty lies in the use of terrestrial laser scanning and 3D modeling for the reconstruction of a destroyed post-military object. The obtained digital model of the fort “Marushka Lis” will be used in web mapping of post-military sites in Lviv region.

On fracture mechanism of additively manufactured triply periodic minimal surface structures using an explicit phase field model

Triply periodic minimal surface (TPMS) structures have been extensively studied for their exceptional mechanical characteristics. However, numerical analysis of their fracture behaviour remains insufficient due to the complexity of the fracture mechanism. This study aims to utilise a new phase field model to predict the mechanical responses and analyse the fracture mechanism of TPMS gyroid (G) and primitive (P) structures. Firstly, the G and P structures were additively manufactured using Ti-6Al-4 V titanium and tested under both axial and oblique compression. Secondly, an explicit phase field model was developed by incorporating the Bao-Wierzbicki fracture model to capture damage initiations. It was found that the developed explicit phase field model enables accurate reproduction of experimental force-displacement responses, deformation modes, crack initiations and propagations for G and P structures under both loading conditions. It was found that medium stress triaxiality tension was the dominant stress state to trigger material damage, regardless of structure and loading condition. Moreover, compared with axial compression, oblique loading introduced a more non-proportional loading history, leading damage initiation points far away from the fracture locus. Further, in comparison with the G structure, the P structure involved more medium and high stress triaxiality tension induced fracture initiations, resulting in more damaged material points. This study offers valuable insight into the fracture mechanism of TPMS structures, which is beneficial to improving the design of these structures.

Comparison of Sagittal Condylar Guidance Angle Obtained by Radiographic Methods and Manual Programming of Articulators in Dentate Patients – A Clinico-radiographic Study

Background: The ultimate goal of advanced procedures in prosthetic dentistry is to construct a prosthesis based on the accurate reproduction of condylar guidance. Aim: To compare the sagittal condylar inclination obtained using the cone-beam computed tomography (CBCT), panoramic image, and two articulator systems. Settings and Design: A cross-sectional study was carried out in 20 dentate patients in the age group of 20–40 years. Materials and Methods: Sagittal condylar guidance angles (SCGAs) were measured on two semi-adjustable articulators (Hanau Wide Vue and Denar Mark 320) using protrusive interocclusal record. SCGAs were also measured on the CBCT scans (CBCT reconstructed panoramic image and CBCT sagittal cross section) and the panoramic images obtained from the patients. The angles were determined on the radiographs by joining two lines: Frankfort’s horizontal plane and the other plane were drawn by connecting the superior-most point on the glenoid fossa and the inferior-most point on the articular eminence. All the measurements were done twice by two operators independently. Statistical Analysis Used: The data were analyzed using the paired t-test and Pearson’s correlation coefficient with a P ≤ 0.05. Results: There was no significant difference between the right and the left side in any of the groups (P ≥ 0.05). In addition, there was no significant difference between the clinical methods (P ≥ 0.05). However, there was a significant difference between the clinical and the radiographic methods (P ≤ 0.05). Furthermore, there was a strong correlation between the clinical and radiographic methods with Pearson’s Correlation coefficient above 0.67. Conclusion: There is a strong correlation between the clinical and radiographic methods. Thus, CBCT and OPG can be used an adjunct to clinical methods to record sagittal condylar guidance.

Comparison of automatic summarization of texts in Russian

The subject of the research in this article is the generalization of texts in Russian using artificial intelligence models. In particular, the authors compare the popular models GigaChat, YaGPT2, ChatGPT-3.5, ChatGPT-4, Bard, Bing AI and YouChat and conduct a comparative study of their work on Russian texts. The article uses datasets for the Russian language, such as Gazeta, XL-Sum and WikiLingua, as source materials for subsequent generalization, as well as additional datasets in English, CNN Dailymail and XSum, were taken to compare the effectiveness of generalization. The article uses the following indicators: ROUGE, BLEU score, BERTScore, METEOR and BLEURT to assess the quality of text synthesis. In this article, a comparative analysis of data obtained during automatic generalization using artificial intelligence models is used as a research method. The scientific novelty of the research is to conduct a comparative analysis of the quality of automatic generalization of texts in Russian and English using various neural network models of natural language processing. The authors of the study drew attention to the new models GigaChat, YaGPT2, ChatGPT-3.5, ChatGPT-4, Bard, Bing AI and YouChat, considering and analyzing their effectiveness in the task of text generalization. The results of the generalization in Russian show that YouChat demonstrates the highest results in terms of the set of ratings, emphasizing the effectiveness of the model in processing and generating text with a more accurate reproduction of key elements of content. Unlike YouChat, the Bard model showed the worst results, representing the model with the least ability to generate coherent and relevant text. The data obtained during the comparison will contribute to a deeper understanding of the models under consideration, helping to make a choice when using artificial intelligence for text summarization tasks as a basis for future developments.

Synthesis of soundfields through irregular loudspeaker arrays based on convolutional neural networks

Most soundfield synthesis approaches deal with extensive and regular loudspeaker arrays, which are often not suitable for home audio systems, due to physical space constraints. In this article, we propose a technique for soundfield synthesis through more easily deployable irregular loudspeaker arrays, i.e., where the spacing between loudspeakers is not constant, based on deep learning. The input are the driving signals obtained through a plane wave decomposition-based technique. While the considered driving signals are able to correctly reproduce the soundfield with a regular array, they show degraded performances when using irregular setups. Through a complex-valued convolutional neural network (CNN), we modify the driving signals in order to compensate the errors in the reproduction of the desired soundfield. Since no ground truth driving signals are available for the compensated ones, we train the model by calculating the loss between the desired soundfield at a number of control points and the one obtained through the driving signals estimated by the network. The proposed model must be retrained for each irregular loudspeaker array configuration. Numerical results show better reproduction accuracy with respect to the plane wave decomposition-based technique, pressure-matching approach, and linear optimizers for driving signal compensation.

Bayesian Gaussian Mixture Models for Enhanced Radar Sensor Modeling: A Data-Driven Approach towards Sensor Simulation for ADAS/AD Development.

In the realm of road safety and the evolution toward automated driving, Advanced Driver Assistance and Automated Driving (ADAS/AD) systems play a pivotal role. As the complexity of these systems grows, comprehensive testing becomes imperative, with virtual test environments becoming crucial, especially for handling diverse and challenging scenarios. Radar sensors are integral to ADAS/AD units and are known for their robust performance even in adverse conditions. However, accurately modeling the radar's perception, particularly the radar cross-section (RCS), proves challenging. This paper adopts a data-driven approach, using Gaussian mixture models (GMMs) to model the radar's perception for various vehicles and aspect angles. A Bayesian variational approach automatically infers model complexity. The model is expanded into a comprehensive radar sensor model based on object lists, incorporating occlusion effects and RCS-based detectability decisions. The model's effectiveness is demonstrated through accurate reproduction of the RCS behavior and scatter point distribution. The full capabilities of the sensor model are demonstrated in different scenarios. The flexible and modular framework has proven apt for modeling specific aspects and allows for an easy model extension. Simultaneously, alongside model extension, more extensive validation is proposed to refine accuracy and broaden the model's applicability.