Location Of Point Research Articles

Dynamic characteristics of edge plasma profiles during the opening of edge islands on the J-TEXT tokamak

On the J-TEXT tokamak, the dynamics of edge magnetic topology during the opening of the edge magnetic islands induced by the external Resonant Magnetic Perturbation (RMP) are investigated. The edge island chain is pushed outward by increasing plasma toroidal current to intersect the poloidally and toroidally localized divertor plate, forming an open magnetic island in the Scrape-Off Layer (SOL). The location of the strike points on the divertor plate predicted by the HINT code is in agreement with the experimental observations. The influence of the magnetic topology on edge plasma profiles has also been investigated using Langmuir probes. The properties of edge Te , ne , Pe and Er profiles are studied as function of three magnetic structures in qa -dependence experiments and two magnetic structures in RMP configuration-dependence experiments. Some common features are observed. Inside the edge closed and SOL remnant islands, flat Pe but non-flat Te and ne profiles are detected. When transitioning from the edge closed island to the partially open island with remnant island, the local flat Pe profile is shifted outward accompanied by a narrower flattened Pe region. The steep slopes of Te , ne and Pe are measured in the SOL regions characterized by a long connection length Lc , and the longer Lc , the steeper slopes. Er exhibits a negative well inside the remnant island with infinite Lc and in the SOL regions where Lc significantly exceeds than the electron mean free path λe , but develops a positive value in the SOL regions where Lc is relatively short.

Drones in Human Aid and Disaster Relief using Thermal Imaging Technology

Disaster Rescue is a very dangerous job to carry out the process without risking more lives in the process as the environment plays a major role. To find the people, requires the system to identify the movement and recognize the human by using the Thermal imaging system in the place of low-temperature areas such as forests, flood areas, Dark places, and so on. Not just thermal but also RGB cameras, stereo cameras and Infrared cameras are used to gain the surrounding situational inference, and by using the intelligent system to identify humans by their body shape from a distance and using the CV pipeline the movement can be identified and confirmed for victims condition in the disaster area. By mounting the optical systems in the Drone, the process makes it safe for the people, and a quick rescue response can be implemented. Using the heavy payload carrying Drone to supply emergency kit and food supplies to the Victims on time. It as well can also act as an emergency communication Network establishment with the GPS to gain the location of a specific point of Disaster regions.

A Framework for Modeling, Optimization, and Musculoskeletal Simulation of an Elbow–Wrist Exosuit

The light weight and compliance of exosuits are valuable benefits not present rigid exoskeleton devices, yet these intriguing features make it challenging to properly model and simulate their interaction with the musculoskeletal system. Tendon-driven exosuits adopt an electrical motor combined with pulleys and cable transmission in the actuation stage. An important aspect of the design of these systems for the load transfer efficacy and comfort of the user is the anchor point positioning. In this paper, we propose a framework, whose first purpose is as a design methodology for the synthesis of an exosuit device, achieved by optimizing the anchor point location. The optimization procedure finds the best 3D position of the anchor points based on the interaction forces between the exosuit and the upper arm. The computation of the forces is based on the combination of a mathematical model of a wrist–elbow exosuit and a dynamic model of the upper arm. Its second purpose is the simulation of the kinematic and physiological effects of the interaction between the arm, the exosuit, and the complex upper limb musculoskeletal system. It offers insights into muscular and exoskeleton loading during operation. The presented experiments involve the development and validation of personalized musculoskeletal models, with kinematic, anthropometric, and electromyographic data measured in a load-lifting task. Simulation of the exosuit operation—coupled with the musculoskeletal model—showed the efficacy of the suit in assisting the wrist and elbow muscles and provided interesting highlights about the impact of the assistance on shoulder muscles. Finally, we provide a possible design of an elbow and wrist exosuit based on the optimized results.

Formant indicators of «velarization». Part I

This article discusses the problem of determining velarization from acoustic data and its relationship to articulation. The aim of the study is to identify the range of formants by which «velarization» can be determined, as well as to determine the location of the highest point of localization of the part of the back of the tongue of the relative palatine arch with this articulation, modeling the sound quality of a specific consonantal sound type. In the course of the study, the methods used at the V.M. Nadelyaev LFEI of the sector of languages of the peoples of Siberia of the IFL SB RAS (Novosibirsk), as well as in the LEFI of the Department of Foreign Languages of the AmSU (Blagoveshchensk). The object of the study is dynamic speech. The subject of the study is «velarization» in languages of different families. The material for the analysis was static and dynamic MRI scans and audio recordings recorded at different times by employees (including the author of this work) of the V.M. Nadelyaev LEFI, made on time and after tomography from the appropriate media. Scientific novelty and theoretical significance of the study: the correlation between F2 , articulation and auditory perception of amplifying articulation of hardness – “velarization” is presented for the first time. The materials and results of the research can be used to develop textbooks on general phonetics, at seminars on dynamic speech analysis, and when writing scientific articles on experimental phonetics. The main conclusions presented in this paper are: 1) the acoustic effect of “velarization” is achieved not only as a result of lifting the back of the tongue to the soft palate not in guttural consonants (velarization), but also between the last third of the second half of the hard palate (prevelarization); 2) correlation analysis of somatic and acoustic material revealed the dependence of format indicators on a certain articulation; 3) a possible range of “velarization” in consonants has been identified – F2 = 1500 Hz – 550 Hz; 4) in the range from 1500 Hz to 1301 Hz, velarization sounds slightly “softer” by ear – a prevelarized consonant than from 1300 Hz to 550 Hz – a velarized consonant.

Extension mechanism of fracturing in liquid nitrogen fractured coal rock dominated by phase change expansion pressure

In this paper, the liquid nitrogen (LN2) fracturing test research using LN2 phase expansion instead of N2 pressurization was carried out in response to the neglected high phase expansion rate characteristic of LN2, an anhydrous fracturing medium. Expansion pressure measurements, infrared temperature measurements, DIC full-field strain measurements and acoustic emission (AE) signal measurements were used as measurement means. The phase change gas expansion pressure, specimen end-face field, internal fracture signal and end-face temperature changes during the fracturing process were explored. The experimental results show that there was a significant difference in the performance of LN2 cold shock damaged specimens and undamaged specimens during fracturing. The change rule of LN2 phase change expansion pressure under no peripheral pressure went through linearly increasing first and then stabilizing, the slope of the linear phase was 0.029 MPa/s, the expansion pressure in the stabilizing phase was 1.2 MPa and lasted for 12s, and then the specimen ruptured. The initiation pressure of the gas fractured specimen was 2.2 MPa. The surface strain of the specimen was significantly increased during the stabilization stage of expansion pressure, and the maximum values of transverse strain and longitudinal strain were 0.059% and 0.071%, respectively, which were increased by 43.9% and 73.2% within 12 s. At the same time, the number of AE localization points increased from 12 to 78, and the location of the localization points gradually expanded from the two sides of the horizontal slot to the top of the horizontal slot and the outer wall of the specimen. There was a low-temperature zone with obvious temperature gradient in the extended area and no such change existed in the gas fractured specimens. Therefore, the fracture initiation pressure of the damaged specimen is lower than that of the undamaged specimen, and the cracks are more likely to expand and become continuous during the fracturing process, thus producing complex cracks. The use of LN2 with high phase change expansion rate can replace the high-pressure pumping of N2, which is of great significance for the reduction of the implementation time and cost of the LN2 fracturing process.

Similarity between a many-body quantum avalanche model and the ultrametric random matrix model

In the field of ergodicity-breaking phases, it has been recognized that quantum avalanches can destabilize many-body localization at a wide range of disorder strengths. This has in particular been demonstrated by the numerical study of a toy model, sometimes simply called the “avalanche model” or the “quantum sun model” [], which consists of an ergodic seed coupled to a perfectly localized material. In this paper, we connect this toy model to a well-studied model in random matrix theory, the ultrametric ensemble. We conjecture that the models share the following features. (1) The location of the critical point may be predicted sharply by analytics. (2) On the localized site, both models exhibit Fock space localization. (3) There is a manifold of critical points. On the critical manifold, the eigenvectors exhibit nontrivial multifractal behavior that can be tuned by moving on the manifold. (4) The spectral statistics at criticality is intermediate between Poisson statistics and random matrix statistics, also tunable on the critical manifold. We confirm numerically these properties. Published by the American Physical Society 2024

Research on the location of measurement points in explosion shock wave pressure testing

Shock wave is an important damage element in ammunition explosion and one of the important technical indicators for evaluating its damage power. Accurately measuring shock wave pressure is of great significance for guiding ammunition design and evaluating damage power. The testing environment in the explosion field is harsh, and the measurement of shock wave pressure is affected by various influencing factors, resulting in inaccurate measurement results and low reliability. The location of pressure measurement points directly affects the measurement results of surface reflection pressure and free field pressure. This study is based on the display explosion dynamics simulation software AUTODYN to conduct simulation analysis of the propagation law of explosion shock wave pressure, analyze the height variation of the three wave point trajectory during the ammunition explosion process, and clarify that the surface reflection pressure measurement points need to be located in the Mach reflection zone, and the free field pressure measurement points need to be located above the height of the three wave points. The research results provide theoretical support for accurate testing of explosion shock wave pressure and have significant engineering application value.

Enhanced Nonlinear Response by Manipulating the Dirac Point at the (111) LaTiO_{3}/SrTiO_{3} Interface.

Tunable spin-orbit interaction (SOI) is an important feature for future spin-based devices. In the presence of a magnetic field, SOI induces an asymmetry in the energy bands, which can produce nonlinear transport effects (V∼I^{2}). Here, we focus on such effects to study the role of SOI in the (111) LaTiO_{3}/SrTiO_{3} interface. This system is a convenient platform for understanding the role of SOI since it exhibits a single-band Hall response through the entire gate-voltage range studied. We report a pronounced rise in the nonlinear longitudinal resistance at a critical in-plane field H_{cr}. This rise disappears when a small out-of-plane field component is present. We explain these results by considering the location of the Dirac point formed at the crossing of the spin-split energy bands. An in-plane magnetic field pushes this point outside of the Fermi contour, and consequently changes the symmetry of the Fermi contours and intensifies the nonlinear transport. An out-of-plane magnetic field opens a gap at the Dirac point, thereby significantly diminishing the nonlinear effects. We propose that magnetoresistance effects previously reported in interfaces with SOI could be comprehended within our suggested scenario.

Suspended Mooring Line Static Analysis using Internal XFlow Capabilities

In the present study, different configurations of a mooring line under a static case are analyzed using the CFD software SIMULIA XFLOW 2022X. Native XFlow geometries employed in the simulation of small springs are used to perform simulations of mooring systems, along with 6 DOF joints, and performing discretization depending on the necessities. Fairlead tensions are compared to experimental data of cables employed in the mooring of DeepCWind semisubmersible platform at 1/40 scale, and to computational model using OPASS. Additionally, the location of different points of the suspended chain in the resting catenary shape is compared to the Quasi-Static model.

Numerical Investigation of the Impact of Subcooling Inlet on Water Flow Boiling Heat Transfer Through a Microchannel

The effect of subcooling inlet has a big effect of the flow patterns for the flow boiling through a microchannel. Higher subcooling lower mass flux will delay the nucleate boiling and vice versa. The water flow boiling inside a microchannel has been analyzed numerically. The microchannel depth was 0.24 mm while the length was 40 mm. The supplied heat fluxes were 500 kW·m-2, 1000 kW·m-2and 1500 kW·m-2 with mass velocities of 400 kg·m-2·s-1 and 800 kg·m-2·s-1. The degrees of subcoooling of inlet water were 5oC, 10oC, 15oC, 20oC, and 25oC. The results showed that the degree subcooling has a considerable impact on both the wall temperature and flow patterns. The rise in the degree of subcooling kept the nucleate flow boiling and retarded the development of convective boiling. In addition, there was a reflection point at which the impact of heat flux on the average of the convective coefficient of heat transfer was altered. The increase in the heat flux may lead to an increase or reduction in the average HTC with respect to the location of the reflection point. The reflection points were 7oC and 5oC for the mass velocities 400 kg·m-2·s-1 and 800 kg·m-2·s-1. Thus, both the degree of subcooling and the heat flux should be simultaneously considered when it comes to the enhancement of HTC during the flow boiling inside the microchannels.

A tool for beam optics design and its application on the VEGA transport line at ELI-NP

The Variable Energy Gamma (VEGA) System, currently under construction at Extreme Light Infrastructure-Nuclear Physics (ELI-NP), is a storage ring-based gamma beam source that aims to provide gamma-ray beams with a variable energy range from 1 MeV to 19.5 MeV to the users. The electron beam transport line has been designed to connect the linear accelerator and the storage ring in the VEGA electron beam system. Considering the geometrical constraints in the accelerator halls and the location of the injection point at the storage ring, the trajectory of the electron beam in the transport line has to first ascend by a 36-degree dog-leg elevation to align with a plane parallel to the storage ring, undergo a 180-degree horizontal turn, and then descend by 36 degrees vertically to reach the injection point at the storage ring. In this paper, we introduce a beam optics tool implemented for the beam optics design and fine-matching in the electron beam transport line. The design of the VEGA transport line including the layout and lattice design, is also described. The tool has been applied to the beam optics design and optimization, utilizing tracking simulations and beam matching for the VEGA transport line lattice. Furthermore, the tool's potential application to similar lattice designs is also discussed.

Lightweight and Stable Multi-Feature Databases for Efficient Geometric Localization of Remote Sensing Images

The surge in remote sensing satellites and diverse imaging modes poses substantial challenges for ground systems. Swift and high-precision geolocation is the foundational requirement for subsequent remote sensing image applications. Breakthroughs in intelligent on-orbit processing now enable on-orbit geometric processing. In the absence of control data on board, a recent trend is to introduce reference data onto satellites. However, the pre-storage of traditional reference images or control point databases presents a significant challenge to the limited on-board data storage capacity. Therefore, oriented to the demand for control information acquisition during on-orbit geometry processing, we propose the construction of lightweight and stable feature databases. Initially, stable feature classes are obtained through iterative matching filtering, followed by re-extracting feature descriptors for each stable feature point location on the training images. Subsequently, the descriptors of each point location are clustered and fused using affinity propagation (AP) to eliminate redundancy. Finally, LDAHash is utilized to quantize floating-point descriptors into binary descriptors, further reducing the storage space. In our experiments, we utilize a variety of feature algorithms to assess the generality of our proposed method, thus extending the scope of the feature database and its applicability to various scenarios. This work plays a crucial role in advancing the technology of on-orbit geometry processing for remote sensing satellites.

Метод автоматического детектирования характерных точек пульсовой волны

The high prevalence of cardiovascular diseases (CVD) requires the development of new methods for their timely preliminary diagnosis. One of the promising approaches in this direction is the analysis of photoplethysmogram (PPG). The article presents an algorithmic method of digital processing of the PPG signal for automatic determination of the position of characteristic points on the pulse wave. This task is relevant, as amplitude and time characteristics of the location of characteristic points allow obtaining information about the state of the cardiovascular system (CVS). The developed method is characterised by low sensitivity to the variability of the signal shape due to the application of differentiation and interpolation procedures. The proposed solution can be used for creation of modern technical means of preliminary diagnostics of CVS.

Skipping without and with hurdles in bipedal macaque: global mechanics.

Macaques trained to perform bipedally used running gaits across a wide range of speeds. At higher speeds they preferred unilateral skipping (galloping). The same asymmetric stepping pattern was used while hurdling across two low obstacles placed at the distance of a stride within our experimental track. In bipedal macaques during skipping, we expected a differential use of the trailing and leading legs. The present study investigated global properties of the effective and virtual leg, the location of the virtual pivot point (VPP), and the energetics of the center of mass (CoM), with the aim of clarifying the differential leg operation during skipping in bipedal macaques. When skipping, macaques displayed minor double support and aerial phases during one stride. Asymmetric leg use was indicated by differences in leg kinematics. Axial damping and tangential leg work did not influence the indifferent peak ground reaction forces and impulses, but resulted in a lift of the CoM during contact of the leading leg. The aerial phase was largely due to the use of the double support. Hurdling amplified the differential leg operation. Here, higher ground reaction forces combined with increased double support provided the vertical impulse to overcome the hurdles. Following CoM dynamics during a stride, skipping and hurdling represented bouncing gaits. The elevation of the VPP of bipedal macaques resembled that of human walking and running in the trailing and leading phases, respectively. Because of anatomical restrictions, macaque unilateral skipping differs from that of humans, and may represent an intermediate gait between grounded and aerial running.

Detecting Quantum Topologic Phase Transitions Through The C-Function

Topological Quantum Field Theory or TQFT is a quantum field theory that calculates topological invariance in measurement theory and mathematical physics. In recent years, several attempts have been made to find efficient observations to determine the TQFT of quasiparticle properties. In this paper, we propose a different and very effective way to detect the critical points of TQFT by considering the system functions. We suggest the C-Function as a novel probe that is accurate for detecting the location of critical points on topological quantum. The C-function uses a holographic model to show a topological quantum phase transition between a simple topological isolation phase and a gapless Weyl semimetal. The quantum tipping point displays a strong Lifshitz-like anisotropy in the spatial direction, and a quantum phase transition that does not follow the standard Landau paradigm. The C-function precisely shows the global features of quantum criticality and distinguishes very accurately between two separate zero-temperature phases. Considering the C-function relationship with entanglement entropy can detect quantum phase transitions and can be applied outside the holographic framework.
 Keywords: quantum topologic, phase transitions, c-function

Evaluating spatially enabled machine learning approaches to depth to bedrock mapping, Alberta, Canada.

Maps showing the thickness of sediments above the bedrock (depth to bedrock, or DTB) are important for many geoscience studies and are necessary for many hydrogeological, engineering, mining, and forestry applications. However, it can be difficult to accurately estimate DTB in areas with varied topography, like lowland and mountainous terrain, because traditional methods of predicting bedrock elevation often underestimate or overestimate the elevation in rugged or incised terrain. Here, we describe a machine learning spatial prediction approach that uses information from traditional digital elevation model derived estimates of terrain morphometry and satellite imagery, augmented with spatial feature engineering techniques to predict DTB across Alberta, Canada. First, compiled measurements of DTB from borehole lithologs were used to train a natural language model to predict bedrock depth across all available lithologs, significantly increasing the dataset size. The combined data were then used for DTB modelling employing several algorithms (XGBoost, Random forests, and Cubist) and spatial feature engineering techniques, using a combination of geographic coordinates, proximity measures, neighbouring points, and spatially lagged DTB estimates. Finally, the results were contrasted with DTB predictions based on modelled relationships with the auxiliary variables, as well as conventional spatial interpolations using inverse-distance weighting and ordinary kriging methods. The results show that the use of spatially lagged variables to incorporate information from the spatial structure of the training data significantly improves predictive performance compared to using auxiliary predictors and/or geographic coordinates alone. Furthermore, unlike some of the other tested methods such as using neighbouring point locations directly as features, spatially lagged variables did not generate spurious spatial artifacts in the predicted raster maps. The proposed method is demonstrated to produce reliable results in several distinct physiographic sub-regions with contrasting terrain types, as well as at the provincial scale, indicating its broad suitability for DTB mapping in general.

Spatial Voting with Incomplete Voter Information

We consider spatial voting where candidates are located in the Euclidean d-dimensional space, and each voter ranks candidates based on their distance from the voter's ideal point. We explore the case where information about the location of voters' ideal points is incomplete: for each dimension, we are given an interval of possible values. We study the computational complexity of finding the possible and necessary winners for positional scoring rules. Our results show that we retain tractable cases of the classic model where voters have partial-order preferences. Moreover, we show that there are positional scoring rules under which the possible-winner problem is intractable for partial orders, but tractable in the one-dimensional spatial setting. We also consider approval voting in this setting. We show that for up to two dimensions, the necessary-winner problem is tractable, while the possible-winner problem is hard for any number of dimensions.

SurgicalSAM: Efficient Class Promptable Surgical Instrument Segmentation

The Segment Anything Model (SAM) is a powerful foundation model that has revolutionised image segmentation. To apply SAM to surgical instrument segmentation, a common approach is to locate precise points or boxes of instruments and then use them as prompts for SAM in a zero-shot manner. However, we observe two problems with this naive pipeline: (1) the domain gap between natural objects and surgical instruments leads to inferior generalisation of SAM; and (2) SAM relies on precise point or box locations for accurate segmentation, requiring either extensive manual guidance or a well-performing specialist detector for prompt preparation, which leads to a complex multi-stage pipeline. To address these problems, we introduce SurgicalSAM, a novel end-to-end efficient-tuning approach for SAM to effectively integrate surgical-specific information with SAM’s pre-trained knowledge for improved generalisation. Specifically, we propose a lightweight prototype-based class prompt encoder for tuning, which directly generates prompt embeddings from class prototypes and eliminates the use of explicit prompts for improved robustness and a simpler pipeline. In addition, to address the low inter-class variance among surgical instrument categories, we propose contrastive prototype learning, further enhancing the discrimination of the class prototypes for more accurate class prompting. The results of extensive experiments on both EndoVis2018 and EndoVis2017 datasets demonstrate that SurgicalSAM achieves state-of-the-art performance while only requiring a small number of tunable parameters. The source code is available at https://github.com/wenxi-yue/SurgicalSAM.

An active learning Kriging model with approximating parallel strategy for structural reliability analysis

With the ever-increasing complexity of engineering problems, active learning functions fused with Kriging models are receiving significant attention and are extensively applied in various reliability analysis methods. It is argued unfavorably that the existing fusion-type methods usually obtain only a single optimal sample point during model updating process. Meanwhile, the information of the used sample points is not sufficiently utilized. To these gaps, this study proposes an adaptive Kriging reliability analysis method based on an approximate parallel computing strategy, namely AP-AK for short. To start with, a new Kriging model update strategy is proposed, where the first selected sample points help to introduce the intermediate model and further search for optimal points closer to the limit state surface. An improved learning function is then proposed to limit the locations of points based on the information of used sample points. The new function is characterized by setting the acceptance and rejection domains of the sample points, which prevents computational waste incurred by local sample point aggregation. Superior performance of the AP-AK method is demonstrated against other Kriging-based methods through five numerical cases and one solid attitude orbit control engine case. The comparison results show that the proposed method exhibits high efficiency and robustness for solving complex reliability analysis problems.

Multi-injection downdraft moving bed reactor for hydrolysis in thermochemical hydrogen production

This paper investigates a downdraft multi-injection moving bed reactor (MBR) for the hydrolysis reaction in the copper-chlorine (Cu–Cl) thermochemical cycle for hydrogen production. The numerical modelling is conducted for a variety of system configurations of the MBR, with a focus on reducing the energy requirement of the reactor while achieving high conversion rates. Several design variables are investigated, including reactor volume, injection point location, and quantity of steam injection. The numerical predictions show an approximate 23% increase in CuCl2 conversion for the multi-injection MBR compared to a single injection design. A maximum conversion of 66.5% is predicted through design parameter variations. Asymptotic behavior for the quantity of injection locations with respect to conversion extent is presented for several different steam to copper ratios. The results and new insights in this paper suggest opportunities for conversion improvement and steam to copper ratio reduction in the hydrolysis reactor through the MBR design.