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1
Khaimovich, A. I., M. A. Bolotov, and E. Yu Pechenina. "Model of virtual balancing of rigid rotors." VESTNIK of Samara University. Aerospace and Mechanical Engineering 21, no. 1 (April 27, 2022): 99–109. http://dx.doi.org/10.18287/2541-7533-2022-21-1-99-109.
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Rotor imbalances have a significant impact on the level of their vibration and reliability. Reduction of rotor imbalances is achieved through static and dynamic balancing that we propose to accomplish by virtual balancing of rigid rotors in two stages. At the first stage mutual orientation of the rotor parts is calculated to compensate their imbalances and couple unbalance. At the second stage the values of the masses and angular coordinates of two correction weights that allow eliminating the residual imbalance of the rotor are determined. The correction weights are placed in two balancing planes of the rotor. A model of virtual balancing is proposed to implement the balancing stages. The model makes it possible to determine the relative angular positions of the rotor parts, the values of the mass of two correction weights and their angular coordinates in the balancing planes. The effectiveness of using the proposed model was verified by performing calculations using the finite element model (FEM) of the rotor in the ANSYS software package. In the course of the study, data were obtained on the values of vibration velocities on the rotor supports. The results obtained show a significant reduction in the vibration velocities of the supports, amounting to 80% of their initial value.
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Shin, Jihye, Sungsoo S. Kim, and Koji Takahashi. "Dynamical Evolution of the Mass Function of the Galactic Globular Cluster System." Proceedings of the International Astronomical Union 3, S246 (September 2007): 433–34. http://dx.doi.org/10.1017/s174392130801613x.
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AbstractUsing the most advanced anisotropic (2D) Fokker-Planck (FP) models, we calculate the evolution of the mass functions of the Galactic globular cluster system (GCMF). Our models include two-body relaxation, binary heating, tidal shocks, dynamical friction, stellar evolution, and realistic cluster orbits. We perform 2D-FP simulations for a large number of virtual globular clusters and synthesize these results to study the relation between the initial and present GCMFs. We found two probable IGCMFs that eventually evolve into the Milky Way GCMF : truncated power-law, and log-normal model with higher initial low mass limit and peak mass than the earlier studies.
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Chen, Wenxing, Chuxiang Zhou, Hao Zhang, Liwei Yan, Shengtai Zhou, Yang Chen, Zhengguang Heng, Huawei Zou, and Mei Liang. "Construction of Prediction Models of Mass Ablation Rate for Silicone Rubber-Based Flexible Ablative Composites Based on a Small Dataset." Applied Sciences 14, no. 17 (September 7, 2024): 8007. http://dx.doi.org/10.3390/app14178007.
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The prediction of the ablation rate of silicone rubber-based composites is of great significance to accelerate the development of flexible thermal protection materials. Herein, a method which combines uniform design experimentation, active learning, and virtual sample generation was proposed to establish a prediction model of the mass ablation rate based on a small dataset. Briefly, a small number of sample points were collected using uniform design experimentation, which were marked to construct the initial dataset and primitive model. Then, data points were acquired from the sample pool and iterated using various integrated algorithms through active learning to update the above dataset and model. Finally, a large number of virtual samples were generated based on the optimal model, and a further optimized prediction model was achieved. The results showed that after introducing 300 virtual samples, the average percentage error of the gradient boosting decision tree (GBDT) prediction model on the test set decreased to 3.1%, which demonstrates the effectiveness of the proposed method in building prediction models based on a small dataset.
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Zhang, Qingxia, Dengzheng Xu, Jilin Hou, Łukasz Jankowski, and Haiyan Wang. "Damage Identification Method Using Additional Virtual Mass Based on Damage Sparsity." Applied Sciences 11, no. 21 (October 29, 2021): 10152. http://dx.doi.org/10.3390/app112110152.
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Damage identification methods based on structural modal parameters are influenced by the structure form, number of measuring sensors and noise, resulting in insufficient modal data and low damage identification accuracy. The additional virtual mass method introduced in this study is based on the virtual deformation method for deriving the frequency-domain response equation of the virtual structure and identify its mode to expand the modal information of the original structure. Based on the initial condition assumption that the structural damage was sparse, the damage identification method based on sparsity with l1 and l2 norm of the damage-factor variation and the orthogonal matching pursuit (OMP) method based on the l0 norm were introduced. According to the characteristics of the additional virtual mass method, an improved OMP method (IOMP) was developed to improve the localization of optimal solution determined using the OMP method and the damage substructure selection process, analyze the damage in the entire structure globally, and improve damage identification accuracy. The accuracy and robustness of each damage identification method for multi-damage scenario were analyzed and verified through simulation and experiment.
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Chen, Ke, Xue Feng Tong, and Xin Fang Wang. "Simulation and Analysis on Vehicle Frontal Crash Based on Virtual Proving Ground." Applied Mechanics and Materials 128-129 (October 2011): 1222–25. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.1222.
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Based on the vehicle crash finite element theory and the virtual proving ground (VPG), vehicle frontal crash is simulated. Under the VPG environment, the unit element meshes are determined for the entire vehicle CAD model, whereas the element types and material parameters, together with welding nodes, contacts and constraints are defined. According to the ECER94 safety regulations, a rigid wall model, along with initial crash conditions is established. By calling the LS-DYNA, the simulation model is calculated and the stress distribution, vehicle body aberration nephogram, energy and acceleration curves are attained. Afterwards, the vehicle crash safety performance is obtained through simulation. Therefore, this approach sets a reference for vehicle mass assessment.
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Verbeke, C., J. Pomoell, and S. Poedts. "The evolution of coronal mass ejections in the inner heliosphere: Implementing the spheromak model with EUHFORIA." Astronomy & Astrophysics 627 (July 2019): A111. http://dx.doi.org/10.1051/0004-6361/201834702.
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Aims. We introduce a new model for coronal mass ejections (CMEs) that has been implemented in the magnetohydrodynamics (MHD) inner heliosphere model EUHFORIA. Utilising a linear force-free spheromak (LFFS) solution, the model provides an intrinsic magnetic field structure for the CME. As a result, the new model has the potential to predict the magnetic components of CMEs at Earth. In this paper, we present the implementation of the new model and show the capability of the new model. Methods. We present initial validation runs for the new magnetised CME model by considering the same set of events as used in the initial validation run of EUHFORIA that employed the Cone model. In particular, we have focused on modelling the CME that was responsible for creating the largest geomagnetic disturbance (Dst index). Two scenarios are discussed: one where a single magnetised CME is launched and another in which we launch all five Earth-directed CMEs that were observed during the considered time period. Four out of the five CMEs were modelled using the Cone model. Results. In the first run, where the propagation of a single magnetized CME is considered, we find that the magnetic field components at Earth are well reproduced as compared to in-situ spacecraft data. Considering a virtual spacecraft that is separated approximately seven heliographic degrees from the position of Earth, we note that the centre of the magnetic cloud is missing Earth and a considerably larger magnetic field strength can be found when shifting to that location. For the second run, launching four Cone CMEs and one LFFS CME, we notice that the simulated magnetised CME is arriving at the same time as in the corresponding full Cone model run. We find that to achieve this, the speed of the CME needs to be reduced in order to compensate for the expansion of the CME due to the addition of the magnetic field inside the CME. The reduced initial speed of the CME and the added magnetic field structure give rise to a very similar propagation of the CME with approximately the same arrival time at 1 au. In contrast to the Cone model, however, the magnetised CME is able to predict the magnetic field components at Earth. However, due to the interaction between the Cone model CMEs and the magnetised CME, the magnetic field amplitude is significantly lower than for the run using a single magnetised CME. Conclusions. We have presented the LFFS model that is able to simulate and predict the magnetic field components and the propagation of magnetised CMEs in the inner heliosphere and at Earth. We note that shifting towards a virtual spacecraft in the neighbourhood of Earth can give rise to much stronger magnetic field components. This gives the option of adding a grid of virtual spacecrafts to give a range of values for the magnetic field components.
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Darman, D. R., A. Suhandi, I. Kaniawati, and A. Samsudin. "Designing of virtual laboratory on elasticity for Physics learning." Journal of Physics: Conference Series 2596, no. 1 (September 1, 2023): 012061. http://dx.doi.org/10.1088/1742-6596/2596/1/012061.
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Abstract Elasticity is one of the materials that students learn through laboratory experiments. In general, real and virtual laboratory conditions are still limited to spring elasticity experiments where the elasticity properties can be observed directly to determine the material’s elastic modulus. While on other objects and materials, elasticity experiments are still problematic to do because of the limitations of measuring instruments and microscopic observation scales. This study aims to produce a virtual laboratory of the Elasticity of various materials using wire for physics learning in universities. This study chose the Development Research (DDR) design with the ADDIE model for its development. The feasibility of the virtual laboratory is seen based on the results of the expert validation test. This research produced a Virtual Laboratory on Elasticity using aluminum, steel, iron, brass, nickel, copper, and tin wire. This virtual laboratory has four variables that can be varied, namely the type of wire material, the mass of the object, the diameter of the wire, and the initial length of the wire. The validation results with expert input show that the Elasticity virtual laboratory is valid and can be used for learning physics in universities.
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Kattel, Parameshwari, Khim B. Khattri, Puskar R. Pokhrel, Jeevan Kafle, Bhadra Man Tuladhar, and Shiva P. Pudasaini. "Simulating glacial lake outburst floods with a two-phase mass flow model." Annals of Glaciology 57, no. 71 (March 2016): 349–58. http://dx.doi.org/10.3189/2016aog71a039.
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AbstractTo simulate a glacial lake outburst flood, we employ a comprehensive physically based general two-phase mass flow model (Pudasaini, 2012). This model accounts for a strong interaction between the solid and fluid phases and incorporates buoyancy and other dominant physical aspects of the mass flows such as enhanced non-Newtonian viscous stress, virtual mass force and generalized drag. Our real two-phase mass flow simulation describes explicit evolution of the solid and fluid phases and the debris bulk as a whole, akin to torrential debris flows or debris floods during glacial lake outburst floods (GLOFs). The emptying of a lake following rapid collapse of a restraining dam, the consequent downslope motion of a mixed solid–fluid mass, and the tendency of the mass to form extruding plumes are analyzed in detail for different flow configurations, volumes, conduit geometries and boundary conditions. The solid and fluid phases evolve completely differently and reveal fundamentally different dynamical behaviours. During the flow, the relatively long fluid tail follows the solid-rich dense frontal surge head. The bulk debris develops into a frontal and side levee as derived from the initial frontal moraine dam. Results show that our high-resolution, unified simulation strategies and the advanced model equations can be applied to study the flow dynamics of a wide range of geophysical mass flows such as snow and rock–ice avalanches, debris flows and flash floods as well as GLOFs. This may help substantially in forming a basis for appropriate mitigation measures against potential natural hazards in high mountain slopes and valleys.
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Илюшкин, Дмитрий, Dmitriy Ilyushkin, Наталья Жижкина, Natalya Zhizhkina, Екатерина Зенцова, and Ekaterina Zentsova. "VIRTUAL SIMULATION OF ROLLER SPUN CASTING." Bulletin of Bryansk state technical university 2016, no. 1 (March 31, 2016): 22–27. http://dx.doi.org/10.12737/18174.
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The work is devoted to the virtual simulation of a sheet roll working layer formation at a technological stage “casting-solidification”. To form a virtual model of a roller mould pouring and foundry solidification there was used a computer modeling system (CMS) which included initial and boundary conditions for a roller mould pouring process with highalloy cast iron in the field of centrifugal force action. The distribution of a metal working layer along an inner surface of a rotating mould at different technological parameters: mass of highalloy cast iron, its density, temperature and pouring velocity, temperature of metal and non-metal parts of a mould at the initial point of time, modes of rotation and conditions of mould cooling and others were investigated. It is established that under the influence of centrifugal forces a free surface of liquid melt obtains a parabolic form. The influence of basic technological parameters upon the vertex position of a paraboloid of revolution of highalloy liquid melt z0 is revealed. It is shown in the paper that it stipulates for the unevenness of a working layer value along a roller barrel. As a result of computations it is obtained that the value of a working layer at lower flanks of barrels is higher than that of upper sides. The average value of such an exceeding makes 0.012 m. As a result of a simulation analysis of a foundry formation process at different technological parameters it is determined that the distance increase between the vertex of a paraboloid of revolution and the metal area investigated raises the working layer evenness along a roller barrel 3.6 times. Hence, the increase of capacity for work of a rolling tool is expected. The results of investigations presented are basic for the works for the increase of centrifugal roller servicing characteristic increase.
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Fishwick, Paul A. "Aesthetic Programming: Crafting Personalized Software." Leonardo 35, no. 4 (August 2002): 383–90. http://dx.doi.org/10.1162/002409402760181178.
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Marrying traditional methods of computer programming with an artistic temperament allows the birth of a new phenomenon: the aesthetic program. The work of the author and his students builds on visual ap-proaches in programming as well as in software modeling, leading toward a gradual evolution from program to model. The need for the aes-thetic model is increased with the importance of personalized, individually tailored media, as found with web-based style sheets and the economic movement termed “mass customization.” The author and his students have formulated the rube Project methodology around the use of 3D web-based virtual-world model construction. Initial results suggest that these models are artistic, while containing symbolism and concise metaphoric mapping sufficient to be executable on a computer.
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Ragauskas, Alyse M. E., Anthony M. Scott, Dudley B. Christie, Danny M. Vaughn, Amy B. Christie, and Dennis W. Ashley. "Strategies for General Surgery Training Programs During the COVID-19 Pandemic." American Surgeon 86, no. 11 (November 2020): 1501–7. http://dx.doi.org/10.1177/0003134820966271.
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The COVID-19 pandemic presented a unique challenge for Medical systems worldwide. Initial response to the crisis situation for the pandemic closely mirrored plans for a mass casualty event. By leveraging resources including human and physical, and by dividing our surgeon workforce into micro teams we were able to create a flexible and responsive infrastructure to address the crisis as it unfolded. By adoption of virtual platforms and equal division of labor, surgical resident education was continued. Specific adjustments to the schedule and curriculum for medical students allowed them to continue their studies safely and on schedule. Our model serves as an example by which hospital systems of similar size may utilize principles of mass casualty preparedness to craft their own plan for a future contagion response strategy.
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Di Egidio, Angelo, and Alessandro Contento. "Seismic Benefits from Coupling Frame Structures with a Hysteretic Mass Damper Inerter." Applied Sciences 13, no. 8 (April 17, 2023): 5017. http://dx.doi.org/10.3390/app13085017.
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The coupling of frame structures with external oscillating bodies, such as rigid walls, dynamic mass absorbers, elastoplastic dampers, or tuned mass dampers, can be effective in reducing the displacements of the structure and protecting it against seismic loads. This paper proposes connecting an external oscillating body to the first story of a frame structure and studying the effectiveness of the coupling by evaluating the reduction in the displacements of the frame structure. The inertial effects of the oscillating body are increased by introducing a virtual mass, provided by an inerter device. The oscillating body, characterized by physical and virtual masses, is connected to the frame structure through a hysteretic device. The study is performed on a dynamically equivalent three-degree-of-freedom (3-DOF) model, whose equations are written using a direct approach. To verify the effectiveness of the protection device, named hysteretic mass damper inerter (HMDI), in reducing the displacements of the frame structure, the displacement of the first story and the drifts of the upper stories are compared to those of the frame structure not connected to the external oscillating body. An initial spectral analysis, performed on the linearized mechanical system, clarifies the role of the parameters of the external device in the dynamic behavior of the coupled system. An additional seismic analysis is performed by using three single earthquake records first, and then a set of seven additional earthquake records selected to be compatible with the design spectrum of Los Angeles. Specific spectral gain maps are used to organize the results of an extensive parametric analysis. They show that the HMDI reduces both displacements and drifts of the structure in large ranges of the parameters that characterize the HMDI. It is found that the proposed protection method is particularly effective for low- and medium-rise frame structures.
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FRÉMOND, MICHEL, and ELISABETTA ROCCA. "WELL-POSEDNESS OF A PHASE TRANSITION MODEL WITH THE POSSIBILITY OF VOIDS." Mathematical Models and Methods in Applied Sciences 16, no. 04 (April 2006): 559–86. http://dx.doi.org/10.1142/s0218202506001261.
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The paper deals with a phase transition model applied to a two-phase system. There is a wide literature on the study of phase transition processes in case that no voids nor overlapping can occur between the two phases. The main novelty of our approach is the possibility of having voids during the phase change. This aspect is described in the model by the mass balance equation whose effects are included by means of the pressure of the system in the dynamical relations. The state variables are the absolute temperature (whose evolution is ruled by the entropy balance equation), the strain tensor (satisfying a quasi-static macroscopic equation of motion), and the volume fractions of the two phases (whose evolutions are described by a vectorial equation coming from the principle of virtual power and related to the microscopic motions). Well-posedness of the initial-boundary value problem associated to the PDEs system resulting from this model is proved.
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Shaomin, Luo, Yan Zou, Xu Cheng, and Li Juan. "Dynamic behavior analysis of a reciprocating mechanism with clearance considering parameter uncertainty." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 6 (December 4, 2019): 1182–95. http://dx.doi.org/10.1177/0954406219891196.
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In this study, a numerical investigation on the dynamic characteristics of a reciprocating mechanism with clearance considering parameter uncertainty is presented. For this purpose, complex space motion between parts is converted into simplified motion of basic component based on the proposed mass substitution model. The contact model in motion parts is established using the Lankarani–Nikravesh model, and the friction effect is considering using a modified Coulomb friction model in the proposed methodology. The comparisons between the numerical results, experimental ones, and virtual simulation ones are carried out. The results show that the proposed methodology has a higher efficiency and calculated precision to predict the dynamic behavior of a reciprocating mechanical system with clearance. In addition, the effects of interval clearance and initial force in the gas-operated chamber on the dynamic behavior are analyzed, respectively. Also, the interaction of two factors is discussed to improve the motion stability.
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Hu, Xiaofei, Yang Zhou, and Qunshan Shi. "Method for 2D-3D Registration under Inverse Depth and Structural Semantic Constraints for Digital Twin City." Applied Sciences 12, no. 17 (August 26, 2022): 8543. http://dx.doi.org/10.3390/app12178543.
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A digital twin city maps a virtual three-dimensional (3D) city model to the geographic information system, constructs a virtual world, and integrates real sensor data to achieve the purpose of virtual–real fusion. Focusing on the accuracy problem of vision sensor registration in the virtual digital twin city scene, this study proposes a 2D-3D registration method under inverse depth and structural semantic constraints. First, perspective and inverse depth images of the virtual scene were obtained by using perspective view and inverse-depth nascent technology, and then the structural semantic features were extracted by the two-line minimal solution set method. A simultaneous matching and pose estimation method under inverse depth and structural semantic constraints was proposed to achieve the 2D-3D registration of real images and virtual scenes. The experimental results show that the proposed method can effectively optimize the initial vision sensor pose and achieve high-precision registration in the digital twin scene, and the Z-coordinate error is reduced by 45%. An application experiment of monocular image multi-object spatial positioning was designed, which proved the practicability of this method, and the influence of model data error on registration accuracy was analyzed.
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Carlotta, Bogena, Sirarpi Hovsepyan, and Paolo Mercorelli. "Conception and analysis of Cascaded Dual Kalman Filters as virtual sensors for mastication activity of stomatognathic craniomandibular system." Journal of Physics: Conference Series 2162, no. 1 (January 1, 2022): 012017. http://dx.doi.org/10.1088/1742-6596/2162/1/012017.
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Abstract The presented work shows a possible methodical approach for parameter estimation of a kinematic and dynamic element that characterizes a human mandibular system during the mastication process using position measurement only. The considered parameters are the velocity, friction coefficient, and the mass of the moving part of the mandibular during the mastication activity of a human. Internal or optical motion sensors can still allow imprecision in the measurements. To overcome these, in the present work a system identification algorithm is designed using a combination of three backward cascaded Kalman Filter, which consists of three Extended Kalman Filters. The identification procedure is validated through a matching criterion based on the estimation of the mass, which is assumed to be known in the first stage of the Kalman Filter structure. Three EKFs are tuned as long as the initial value of the mandibular mass is achieved as an estimation of the third one. This is due to the fact that the optimization procedure tries to optimize a non-convex optimization problem that can admit more than one solution. The main contribution of this project is designing state estimation dynamic system, which accurately estimates friction with a linear time varying model. Friction coefficient plays an important role in the early diagnosis of temporomandibular joints disorders, since it is very low under normal condition, and an increase may be associated with abnormalities. Computer simulations show the effectiveness of the proposed method to accurately estimate friction dynamics and refrain from complex nonlinearities.
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Feng, Xiao Qiang, Zhan Ke Li, Jian Hua Sang, and Bi Feng Song. "Optimization of Sonic Boom Suppression by Off-Body Energy Deposition." Applied Mechanics and Materials 477-478 (December 2013): 7–13. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.7.
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Sonic boom suppression method is the key technology of next generation supersonic aircraft. Low boom mechanism of the off-body energy deposition is analyzed by using the thermal chocking model. The mass flux of energy deposition region is small than no energy deposition region, and off-body energy deposition will induce a bow shock wave. The mechanism of off body energy deposition is similar with quiet spike, so it can be regard as a virtual quiet spike. Off-body energy deposition analysis software is developed based on CFD, waveform parameter method and NSGA-II genetic algorithm. The location coordinate, value, shape and location number of energy deposition are the key parameters in low boom design. Initial pressure of optimized energy deposition decrease near about 54.65 than no energy deposition, and rise time increase 543.2%.
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Liu, Aihua, Qiang Yang, Xin Zhang, and Weibo Deng. "Direction-of-Arrival Estimation for Coprime Array Using Compressive Sensing Based Array Interpolation." International Journal of Antennas and Propagation 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/6425067.
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A method of direction-of-arrival (DOA) estimation using array interpolation is proposed in this paper to increase the number of resolvable sources and improve the DOA estimation performance for coprime array configuration with holes in its virtual array. The virtual symmetric nonuniform linear array (VSNLA) of coprime array signal model is introduced, with the conventional MUSIC with spatial smoothing algorithm (SS-MUSIC) applied on the continuous lags in the VSNLA; the degrees of freedom (DoFs) for DOA estimation are obviously not fully exploited. To effectively utilize the extent of DoFs offered by the coarray configuration, a compressing sensing based array interpolation algorithm is proposed. The compressing sensing technique is used to obtain the coarse initial DOA estimation, and a modified iterative initial DOA estimation based interpolation algorithm (IMCA-AI) is then utilized to obtain the final DOA estimation, which maps the sample covariance matrix of the VSNLA to the covariance matrix of a filled virtual symmetric uniform linear array (VSULA) with the same aperture size. The proposed DOA estimation method can efficiently improve the DOA estimation performance. The numerical simulations are provided to demonstrate the effectiveness of the proposed method.
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Drama, Özge, Johanna Vielemeyer, Alexander Badri-Spröwitz, and Roy Müller. "Postural stability in human running with step-down perturbations: an experimental and numerical study." Royal Society Open Science 7, no. 11 (November 2020): 200570. http://dx.doi.org/10.1098/rsos.200570.
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Postural stability is one of the most crucial elements in bipedal locomotion. Bipeds are dynamically unstable and need to maintain their trunk upright against the rotations induced by the ground reaction forces (GRFs), especially when running. Gait studies report that the GRF vectors focus around a virtual point above the centre of mass (VP A ), while the trunk moves forward in pitch axis during the stance phase of human running. However, a recent simulation study suggests that a virtual point below the centre of mass (VP B ) might be present in human running, because a VP A yields backward trunk rotation during the stance phase. In this work, we perform a gait analysis to investigate the existence and location of the VP in human running at 5 m s −1 , and support our findings numerically using the spring-loaded inverted pendulum model with a trunk. We extend our analysis to include perturbations in terrain height (visible and camouflaged), and investigate the response of the VP mechanism to step-down perturbations both experimentally and numerically. Our experimental results show that the human running gait displays a VP B of ≈−30 cm and a forward trunk motion during the stance phase. The camouflaged step-down perturbations affect the location of the VP B . Our simulation results suggest that the VP B is able to encounter the step-down perturbations and bring the system back to its initial equilibrium state.
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Li, Junqiu, Yihe Wang, and Yizheng Wang. "Optimal control for jitter suppression of clutch engagement in upshift process of electric vehicles." Advances in Mechanical Engineering 8, no. 12 (December 2016): 168781401667484. http://dx.doi.org/10.1177/1687814016674847.
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In the shift process of large-order automatic transmission, jitter phenomenon is common in clutch engagement process, which greatly affects the ride comfort of the vehicle. In this article, the jitter dynamic model of clutch engagement process was established with lumped mass method and virtual displacement principle. Specific to clutch engagement stage, the optimal control of the coordination between driving motor and wet clutch was studied. In accordance with the jitter dynamic model, the state–space equation with controlling variables of motor torque and clutch friction torque was established. In this optimization problem, the torsion angle, torsion angular velocity, and shift jerk are selected as optimization targets. Utilizing the linear quadratic optimal control theory, the optimal trajectory of motor torque and clutch friction torque was obtained. Aiming at the dynamic responses in clutch engagement process, the optimal control in different conditions of weight coefficients, initial torsion angles, and resistance torques was studied. Results showed that the optimal control strategy could obviously reduce the jitter; in addition, the weight coefficient should be determined according to actual situation reasonably.
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Du, Chenxi, Xianzhi Ao, Bingxian Luo, Jingjing Wang, Chong Chen, Xin Xiong, Xin Wang, and Gang Li. "Ensemble Numerical Simulations of Realistic SEP Events and the Inspiration for Space Weather Awareness." Research in Astronomy and Astrophysics 22, no. 2 (February 1, 2022): 025003. http://dx.doi.org/10.1088/1674-4527/ac3adb.
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Abstract The solar energetic particle (SEP) event is a kind of hazardous space weather phenomena, so its quantitative forecast is of great importance from the aspect of space environmental situation awareness. We present here a set of SEP forecast tools, which consists of three components : (1) a simple polytropic solar wind model to estimate the background solar wind conditions at the inner boundary of 0.1 AU (about 20 R ⊙); (2) an ice-cream-cone model to estimate the erupted coronal mass ejection (CME) parameters; and (3) the improved Particle Acceleration and Transport in the Heliosphere (iPATH) model to calculate particle fluxes and energy spectra. By utilizing the above models, we have simulated six realistic SEP events from 2010 August 14 to 2014 September 10, and compared the simulated results to the Geostationary Operational Environmental Satellites (GOES) spacecraft observations. The results show that the simulated fluxes of >10 MeV particles agree with the observations while the simulated fluxes of >100 MeV particles are higher than the observed data. One of the possible reasons is that we have adopted a simple method in the model to calculate the injection rate of energetic particles. Furthermore, we have conducted the ensemble numerical simulations over these events and investigated the effects of different background solar wind conditions at the inner boundary on SEP events. The results imply that the initial CME density plays an important role in determining the power spectrum, while the effect of varying background solar wind temperature is not significant. Naturally, we have examined the influence of CME initial density on the numerical prediction results for virtual SEP cases with different CME ejection speeds. The result shows that the effect of initial CME density variation is inversely associated with CME speed.
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Popov, A. M., S. M. Muzhichek, M. A. Korzun, L. A. Maslova, A. K. Savenko, S. V. Khrulin, and A. A. Skrynnikov. "Mathematical Model of Impact Projectile Flight Dynamics as an Element of its Digital Twin." Mekhatronika, Avtomatizatsiya, Upravlenie 25, no. 1 (January 10, 2024): 31–42. http://dx.doi.org/10.17587/mau.25.31-42.
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This paper gives the analysis of the structure and characteristics of the mathematical model of the impact projectile’s flight dynamics. The model is designed for being used as an element of the projectile’s digital twin. The model is based on differential motion equations of a gyro-stabilized solid with an axisymmetric mass distribution. Different types of angle variables were chosen for describing aerodynamics and formulating equations of motion. Non-linear (considering the nutation angle) dependences for aerodynamic coefficients are proposed. They are created by applying proven scientific concepts and research methods in aerodynamics of axisymmetric body and by comparing with known numerical and experimental results obtained in exterior ballistics of gyro-stabilized aviation and artillery projectiles. Special aspects of initial conditions for angles and angular velocity were also studied. Since the impact projectile is considered as an axially symmetric body, its self-rotation angle is not of practical inte rest. Using algebraic manipulations, the differential equation for this angle was eliminated from the set of equations. This has made it possible to significantly reduce stiff of the remaining system of differential equations. The Dormand-Prince method is recommended as a method of numerical integration. The method of the eight-order (with seventh-order uncertainty estimate) allows getting the high accurate solution of the differential equations set under relatively small computing costs. The model allows computing the projectile trajectory under various initial conditions, including the flight with high nutation angles up to 87°—89°. As a result, there is a possibility to determine the nature of the interaction between impact projectiles and typical targets (ricochet, surface effect, after-penetration effect) within a wide range of approach angles to the target’s surface (skin) unattainable during the full-scale tests. The possibility of solving similar problems allows to recommend the designed model as an element of the impact projectile’s digital twin intended for testing its exterior ballistics on the digital (virtual) test range. All testing calculations and final modeling were made by using the "GNU Octave" computational software package.
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Lailatussaadah, Lailatussaadah, Asyraf Isyraqi Bin Jamil, and Fakhrul Adabi Bin Abdul Kadir. "Forging New Educational Horizons: Unveiling Virtual Extracurricular Transformation in High School Amidst the COVID- 19." Idarah (Jurnal Pendidikan dan Kependidikan) 7, no. 1 (June 30, 2023): 69–84. http://dx.doi.org/10.47766/idarah.v7i1.1484.
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Abstract: The educational landscape has undergone significant transformations in the wake of the COVID-19 pandemic, with one notable change being the adoption of virtual platforms for conducting extracurricular activities. This approach marks a departure from traditional practices, as these activities were previously never executed in such a manner. Therefore, this study aims to identify the various forms of virtual implementation of extracurricular activities during the COVID-19 pandemic. In this study, a mixed-methods approach is intended to analyze needs as an initial step in designing the implementation of extracurricular activities during the pandemic. Data was gathered through interviews with the deputy head of the student affairs department and teachers, as well as quantitative data gathered through questionnaires distributed to 20 students from SMAN 3 Banda Aceh. An interactive model and percentage statistics were then used to analyze the data. According to the conclusions drawn from the needs analysis, students chose to implement extracurricular activities in two ways: virtually and non-virtually. Video editing (27.8%), spelling bee (27.8%), cooking class (16.7%), and vocal solo (5.6%) were the four most popular virtual activities. As a result, it is reasonable to deduce that students opted to persist with virtual implementations of extracurricular activities amidst the COVID-19 pandemic, particularly placing emphasis on these four highlighted activities. Subsequent to this research, a study will be undertaken to formulate the design and procedural framework for the execution of extracurricular activities amid the COVID-19 pandemic. Abstrak: Perubahan besar dalam dunia pendidikan telah terjadi pasca pandemic Covid-19. Salah satunya adalah pelaksanaan kegiatan ekstrakurikuler yang dapat dilaksanakan secara virtual, padahal hal itu belum pernah dilakukan sebelumnya. Penelitian ini bertujuan untuk mengidentifikasikan bentuk-bentuk pelaksanaan kegiatan ektrakurikuler yang dapat dilaksanakan secara virtual/daring pada masa pandemi covid-19. Penggunaan metode mix method dalam penelitian ini bertujuan untuk melakukan analisis kebutuhan sebagai sebuah kegiatan awal dalam melakukan rancang bangun terhadap pelaksanaan kegiatan ekstrakurikuler pada masa pandemi covid-19. Pengumpulan data dilakukan melalui wawancara pada wakil kepala bidang kesiswaan, guru, dan data kuantitatif melalui angket yang disebarkan kepada 20 orang siswa SMAN 3 Banda Aceh, selanjutnya data dianalisis dengan model interaktif dan statistic persentase. Hasil penelitian dari analisis kebutuhan menunjukkan bahwa siswa memilih kegiatan ekstrakurikuler diilaksanakan dalam dua cara, yaitu secara virtual dan non virtual. Untuk kegiatan virtual ditemukan 4 kegiatan yang sangat diminati siswa, yaitu video editing sebanyak 27,8%, speling bee sebanyak 27,8%, kelas memasak sebanyak 16,7%, vocal solo 5,6%. Dengan demikian dapat disimpulkan peserta didik memutuskan tetap melaksanakan kegiatan ekstrakurikuler pada masa pandemic covid-19 secara virtual dengan kegiatan 4 kegiatan tersebut. Penelitian ini akan dilanjutkan dengan penelitian pengembangan rancang bangun langkah kegiatan ektrakurikuler pada masa pandemi covid-19.
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Vaddi, Kiran, and Olga Wodo. "Active Knowledge Extraction from Cyclic Voltammetry." Energies 15, no. 13 (June 23, 2022): 4575. http://dx.doi.org/10.3390/en15134575.
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Cyclic Voltammetry (CV) is an electro-chemical characterization technique used in an initial material screening for desired properties and to extract information about electro-chemical reactions. In some applications, to extract kinetic information of the associated reactions (e.g., rate constants and turn over frequencies), CV curve should have a specific shape (for example an S-shape). However, often the characterization settings to obtain such curve are not known a priori. In this paper, an active search framework is defined to accelerate identification of characterization settings that enable knowledge extraction from CV experiments. Towards this goal, a representation of CV responses is used in combination with Bayesian Model Selection (BMS) method to efficiently label the response to be either S-shape or not S-shape. Using an active search with BMS oracle, we report a linear target identification in a six-dimensional search space (comprised of thermodynamic, mass transfer, and solution variables as dimensions). Our framework has the potential to be a powerful virtual screening technique for molecular catalysts, bi-functional fuel cell catalysts, and other energy conversion and storage systems.
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Kazakova, M., and G. L. Richard. "A new model of shoaling and breaking waves: one-dimensional solitary wave on a mild sloping beach." Journal of Fluid Mechanics 862 (January 15, 2019): 552–91. http://dx.doi.org/10.1017/jfm.2018.947.
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We present a new approach to model coastal waves in the shoaling and surf zones. The model can be described as a depth-averaged large-eddy simulation model with a cutoff in the inertial subrange. The large-scale turbulence is explicitly resolved through an extra variable called enstrophy while the small-scale turbulence is modelled with a turbulent-viscosity hypothesis. The equations are derived by averaging the mass, momentum and kinetic energy equations assuming a shallow-water flow, a negligible bottom shear stress and a weakly turbulent flow assumption which is not restrictive in practice. The model is fully nonlinear and has the same dispersive properties as the Green–Naghdi equations. It is validated by numerical tests and by comparison with experimental results of the literature on the propagation of a one-dimensional solitary wave over a mild sloping beach. The wave breaking is characterized by a sudden increase of the enstrophy which allows us to propose a breaking criterion based on the new concept of virtual enstrophy. The model features three empirical parameters. The first one governs the turbulent dissipation and was found to be a constant. The eddy viscosity is determined by a turbulent Reynolds number depending only on the bottom slope. The third parameter defines the breaking criterion and depends only on the wave initial nonlinearity. These dependences give a predictive character to the model which is suitable for further developments.
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Shastry, K. Aditya, B. A. Manjunatha, T. G. Mohan Kumar, and D. U. Karthik. "Generative Adversarial Networks Based Scene Generation on Indian Driving Dataset." Journal of ICT Research and Applications 17, no. 2 (August 31, 2023): 181–200. http://dx.doi.org/10.5614/itbj.ict.res.appl.2023.17.2.4.
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The rate of advancement in the field of artificial intelligence (AI) has drastically increased over the past twenty years or so. From AI models that can classify every object in an image to realistic chatbots, the signs of progress can be found in all fields. This work focused on tackling a relatively new problem in the current scenario-generative capabilities of AI. While the classification and prediction models have matured and entered the mass market across the globe, generation through AI is still in its initial stages. Generative tasks consist of an AI model learning the features of a given input and using these learned values to generate completely new output values that were not originally part of the input dataset. The most common input type given to generative models are images. The most popular architectures for generative models are autoencoders and generative adversarial networks (GANs). Our study aimed to use GANs to generate realistic images from a purely semantic representation of a scene. While our model can be used on any kind of scene, we used the Indian Driving Dataset to train our model. Through this work, we could arrive at answers to the following questions: (1) the scope of GANs in interpreting and understanding textures and variables in complex scenes; (2) the application of such a model in the field of gaming and virtual reality; (3) the possible impact of generating realistic deep fakes on society.
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Kotova, Ekaterina O. "Linguoecological Assessment of the Readability of Russian Longreads (Statistical Approach)." Proceedings of Southern Federal University. Philology 2021, no. 2 (June 30, 2021): 67–76. http://dx.doi.org/10.18522/1995-0640-2021-2-67-76.
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The study is devoted to the use of a mathematical model for calculating the readability index of a text as one of the tools for linguoecological assessment of a journalistic text. The research material was 20 longreads published in Russian electronic editions. The specificity of the research object lies in the fact that it is both a kind of journalistic discourse and an element of the digital space. In the study formal mathematical and statistical research methods were used, based on the determination of readability values, i.e. ease of human perception of texts. A linguoecological assessment of Russian-language longreads was carried out on the basis of the universal readability indices, adapted to the Russian language, – the Flesch and the Flesch-Kincaid indices. The results obtained showed that longreads designed for a wide mass readership have a readability index ranging from “medium” to “very high”. Texts in which oral speech is actively transmitted have a high readability index. The author of the article concludes that this method should be used in the initial assessment of a journalistic text at the stage of editing the material, as well as in the framework of the linguoecological examination of significant publications. The study of the statistical parameters of journalistic materials made in this genre will help not only to assess the linguoecological situation in the space of modern virtual media, but also to include the results obtained in the overall picture of the analysis of the linguoecological situation in the Russian-speaking virtual space.
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Mousaviraad, Mohammad, Mehari Z. Tekeste, and Kurt A. Rosentrater. "Calibration and Validation of a Discrete Element Model of Corn Using Grain Flow Simulation in a Commercial Screw Grain Auger." Transactions of the ASABE 60, no. 4 (2017): 1403–15. http://dx.doi.org/10.13031/trans.12200.
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Abstract. Screw augers are primary grain conveying equipment in the agriculture industry. Quantitative prediction of grain conveyance using screw augers requires better understanding and measurement of bulk particle-particle and particle-rigid-body interactions. Discrete element modeling (DEM) has potential to simulate particle dynamics and flow within a screw auger and thus provide simulation-based guidance for auger design and operating parameters. The objective of this study was to develop a DEM corn model calibration methodology and validation for combine-harvested corn flow in a commercial screw auger. The methodology used a virtual design of experiment (DOE) varying DEM corn parameters and calibration to match grain pile formation expressed in a normalized angle of repose (AOR). DEM corn particle shape was approximated using 1-sphere and clumped spheres (2-sphere, 5-sphere, and 13-sphere) matching the measured physical parameters of equivalent geometrical diameter, 2D axial dimensions, 3D axial dimensions, and detailed CAD-approximated corn dimensions, respectively. For each DEM corn shape approximation, a virtual DOE using Latin square hypercube design with four independent DEM Hertz-Mindlin contact model interaction coefficients was developed. The DEM assembly of particles matching the initial conditions of the AOR test was created in EDEM 2.7. From the quasi-static AOR of corn flow in the AOR tests and EDEM simulations, the mean square error (MSE), a sum of square difference in grain heights in the AOR tests and EDEM simulations, was used as a bulk material dependent response for the calibration process. The DEM 2-sphere corn shape model and the material interaction coefficients showed the minimum MSE (5.31 mm) compared to the 1-sphere, 5-sphere, and 13-sphere models. With the best DEM corn shape model (2-sphere) and DEM model parameters with the minimum MSE, validation of the DEM in predicting corn flow in a commercial screw auger in laboratory tests at two rotational speeds (250 and 450 rpm) was performed and showed good prediction (within 5% relative error) in matching the change in mass flow rate with the change in auger rotational speed. Keywords: Angle of repose, Corn, Discrete element modeling (DEM), Screw grain auger.
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Frith, H., and R. Blake. "The mechanical power output and hydromechanical efficiency of northern pike (Esox lucius) fast-starts." Journal of Experimental Biology 198, no. 9 (September 1, 1995): 1863–73. http://dx.doi.org/10.1242/jeb.198.9.1863.
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The mechanical power output and hydrodynamic efficiency of northern pike, Esox lucius, during acceleration from rest (fast-start) are calculated from hydrodynamic theory for two kinematic patterns, C-starts (used in escape) and S-starts (used in prey capture). The Weihs model is employed and modified to calculate the mechanical power produced by a fish during a fast-start. A term is included for the power required to accelerate body sections laterally. Lateral deceleration of fish body sections and their associated added mass are expressed as an active process requiring energy expenditure or as a passive process requiring no energy expenditure. In addition, two methods of calculating useful power (the power used to accelerate the virtual mass of the fish, i.e. fish body mass + longitudinal added mass, in the direction of motion), one derived from the Weihs model and the second by summing the changes in kinetic energy of the virtual mass of the fish during a fast-start, are compared and found to give similar estimates of useful power (not significantly different; differences average 22 %). Comparisons of the kinematics and performance of C- and S-starts reveal that C-starts are consistently terminated after two tail flips (stages 1 and 2) whereas S-starts continue for 3­6 tail flips (stages 3­6). In addition, acceleration during C-starts is more rapid and velocities are higher (2.3­2.8 m s-1) than during S-starts (0.8­1.8 m s-1) over the first 100 ms. However, the peak velocities achieved during S-starts and C-starts are similar over the duration of a fast-start. The superior acceleration rates achieved during the initial stages of a C-start can be explained, in part, by the use of greater maximum angles of attack, higher lateral and perpendicular velocities and larger maximum forces by the caudal fin. Hydrodynamic efficiencies for fast-starts range from 0.16 to 0.39, values that are lower than those observed during either burst-and-coast or steady swimming. Efficiencies are lower for S-starts than for C-starts during the first two tail beats. S-start efficiencies increase with each subsequent tail flip and the maximum efficiencies realised are similar to those achieved during C-starts. Power output during C- and S-starts (449.0 and 394.9 W kg-1 muscle fibre, respectively) approaches the theoretical maximum for vertebrate striated muscle (500 W kg-1). Also, the inferred muscle stress is close to the predicted optimum for maximum power output, at 30 % of the maximum isometric stress recorded for isolated fast muscle fibres. These measurements suggest that fast-start performance is near a physiological limit and is probably constrained by muscle function. The superior acceleration rates achieved by C-starts over S-starts are explained in part by differences in hydrodynamic efficiency, whereas power outputs are similar.
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Ding, Xiaoyu, Wei Wang, and Xinbo Chen. "Vibration Principles Research of Novel Power Electronic Module as Dynamic Vibration Absorber for Chassis-By-Wire." Machines 12, no. 12 (December 19, 2024): 932. https://doi.org/10.3390/machines12120932.
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This paper presents a novel power electronic module (PEM) for chassis-by-wire in passenger cars. The PEM is supposed to be installed in a close-to-wheel position, which provides electrical interfaces with a power harness and signal harness. When the vehicle is driving, the PEM works as a dynamic vibration absorber (DVA) to diminish the negative effects of un-sprung mass. Based on the vibration system model, the mechanical principles are analyzed and the design parameters are mathematically optimized. For a comparison of different configuration schemes with an in-wheel motor (IWM), we take the condition of a vehicle driving at a speed of 15 m/s on a C-class road to examine indicators of vehicle body acceleration, wheel dynamic load, and suspension dynamic deflection. The calculation results prove that the system has advantages in ride comfort and wheel grounding characteristics. For the detailed design of the machine, we build a digital virtual prototype for simulation. Compared to the initial state, the optimized DVA configuration has obvious suppression in component vibration, including the vehicle body, the IWM, and the PEM. The frequency sweep analysis proves a robust result, which ensures that the frequency and amplitude are both within the vibration tolerance range of PEM operations.
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Amoskov, Victor M., Vyacheslav N. Vasiliev, Elena I. Gapionok, Georgy G. Gulbekyan, Nikolai S. Edamenko, Ivan A. Ivanenko, Nikolay Yu Kazarinov, et al. "Modelling and design of permanent magnet multipoles for beam transport and focusing. I. Selection of optimal design and parameters." Vestnik of Saint Petersburg University. Applied Mathematics. Computer Science. Control Processes 17, no. 4 (2021): 313–29. http://dx.doi.org/10.21638/11701/spbu10.2021.401.
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The design and specification choices are described for a PM quadrupole used to enable beam transport in a cyclotron. First an analytic study with a simplified 2D model is performed to give initial values for magnet configuration and performance. Characteristics of PM blocks and cylinders are analysed. Then a 3D parametrized model is used to solve the direct magnetostatic problem and accurately define quad specifications. Simulations are carried out with KOMPOT electromagnetic code utilizing the differential formulation. The regulariza- tion method is applied to solve the inverse problem. Magnetic characteristics, dimensions and shapes of the PM units and iron parts are determined in order to reach the specified field gradient. Possible correction of the resulting the ideal specification is discussed with respect to additional constraints put by practical implementation. Candidate PM materials are proposed. Simulated field maps are presented. The method described may serve as a basis for virtual prototyping and be integrated into end-to-end design and construction of magnet systems.
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Cheuk, Bonnie. "Applying Sense-Making and Narrative Techniques to Capture Lessons Learnt." Journal of Information & Knowledge Management 06, no. 03 (September 2007): 165–71. http://dx.doi.org/10.1142/s0219649207001780.
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This case study demonstrates how we have designed a knowledge management project around story-telling ("narrative" feedback). The aim is to create a global virtual space for sharing of good and bad experiences from the commissioning pilot. This project is also designed to help senior managers understand the experiences of the pilot phase of a major change programme within the British Council. The change programme (referred to as commissioning change programme) is about introducing a new internal model/process to release funding to support new products and services' development and implementation. The research design is informed by Dervin's sense-making theory and Snowden's Cynefin framework and mass narrative representation tools. Telephone and face-to-face interviews were conducted with 30 colleagues in the UK and overseas. An initial indirect question was posed to respondents—"What was your experience with the commissioning pilot?"—to capture their stories. The stories told were transcribed and indexed and patterns were identified. The analysis helps to highlight the problematic areas as well as opportunities for improvement. This case study demonstrates the potential of using narratives to evaluate and capture learning points which can be viewed by managers and staff using multiple perspectives. This approach complements the traditional approach of producing an evaluation report which would be written for a specific group of audience, such as the senior management team.
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Ngo, Ba-Viet, and Thanh-Hai Nguyen. "A Semi-Automatic Wheelchair with Navigation Based on Virtual-Real 2D Grid Maps and EEG Signals." Applied Sciences 12, no. 17 (September 4, 2022): 8880. http://dx.doi.org/10.3390/app12178880.
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A semi-automatic wheelchair allows disabled people to possibly control in an indoor environment with obstacles and targets. The paper proposes an EEG-based control system for the wheelchair based on a grid map designed to allow disabled people to reach any preset destination. In particular, the grid map is constructed by dividing it into grid cells that may contain free spaces or obstacles. The map with the grid cells is simulated to find the optimal paths to the target positions using a Deep Q-Networks (DQNs) model with the Parametric Rectified Linear Unit (PReLU) activation function, in which a novel algorithm for finding the optimal path planning by converting wheelchair actions is applied using the output parameters of the DQNs. For the wheelchair movement in one real indoor environment corresponding to the virtual 2D grid map, the initial position of the wheelchair will be determined based on natural landmarks and a graphical user interface designed for on-screen display can support disabled people in selecting the desired destination from a list of predefined locations using Electroencephalogram (EEG) signals by blinking eyes. Therefore, one user can easily and safely control the wheelchair using an EEG system to reach the desired target when the wheelchair position and destination are determined in the indoor environment. As a result, a grid map was developed and experiments for the semi-automatic wheelchair control were performed in real indoor environments to illustrate the effectiveness of the proposed method. In addition, the system is a platform to develop different types of controls depending on the types of user disabilities and different environmental maps built.
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Yan, Lingyun, Guowu Wei, Zheqi Hu, Haohua Xiu, Yuyang Wei, and Lei Ren. "Low-Cost Multisensor Integrated System for Online Walking Gait Detection." Journal of Sensors 2021 (August 14, 2021): 1–15. http://dx.doi.org/10.1155/2021/6378514.
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A three-dimensional motion capture system is a useful tool for analysing gait patterns during walking or exercising, and it is frequently applied in biomechanical studies. However, most of them are expensive. This study designs a low-cost gait detection system with high accuracy and reliability that is an alternative method/equipment in the gait detection field to the most widely used commercial system, the virtual user concept (Vicon) system. The proposed system integrates mass-produced low-cost sensors/chips in a compact size to collect kinematic data. Furthermore, an x86 mini personal computer (PC) running at 100 Hz classifies motion data in real-time. To guarantee gait detection accuracy, the embedded gait detection algorithm adopts a multilayer perceptron (MLP) model and a rule-based calibration filter to classify kinematic data into five distinct gait events: heel-strike, foot-flat, heel-off, toe-off, and initial-swing. To evaluate performance, volunteers are requested to walk on the treadmill at a regular walking speed of 4.2 km/h while kinematic data are recorded by a low-cost system and a Vicon system simultaneously. The gait detection accuracy and relative time error are estimated by comparing the classified gait events in the study with the Vicon system as a reference. The results show that the proposed system obtains a high accuracy of 99.66% with a smaller time error (32 ms), demonstrating that it performs similarly to the Vicon system in the gait detection field.
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Kulkarni, Siddharth, David John Edwards, Craig Chapman, M. Reza Hosseini, and De-Graft Owusu-Manu. "A preliminary mechanical design evaluation of the Wikispeed car: for light-weighting implications." Journal of Engineering, Design and Technology 17, no. 1 (February 4, 2019): 230–49. http://dx.doi.org/10.1108/jedt-09-2018-0154.
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Purpose Road passenger transportation faces a global challenge of reducing environmental pollution and greenhouse gas emissions because of the vehicle weight increases needed to enhance passenger safety and comfort. This paper aims to present a preliminary mechanical design evaluation of the Wikispeed Car (with a focus on body bending, body torsion and body crash) to assess light-weighting implications and improve the vehicle’s environmental performance without compromising safety. Design/methodology/approach For this research, finite element analysis (FEA) was performed to examine the Wikispeed chassis for light-weighting opportunities in three key aspects of the vehicle’s design, namely, for body bending the rockers (or longitudinal tubes), for body torsion (again on the rockers but also the chassis as a whole) and for crash safety – on the frontal crash structure. A two-phase approach was adopted, namely, in phase one, a 3D CAD geometry was generated and in phase, two FEA was generated. The combination of analysis results was used to develop the virtual model using FEA tools, and the model was updated based on the correlation process. Findings The research revealed that changing the specified material Aluminium Alloy 6061-T651 to Magnesium EN-MB10020 allows vehicle mass to be reduced by an estimated 110 kg, thus producing a concomitant 10 per cent improvement in fuel economy. The initial results imply that the current beam design made from magnesium would perform worst during a crash as the force required to buckle the beam is the lowest (between 95.2 kN and 134 kN). Steel has the largest bandwidth of force required for buckling and also requires the largest force for buckling (between 317 kN and 540 kN). Originality/value This is the first study of its kind to compare and contrast between material substitution and its impact upon Wikispeed car safety and performance.
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Neupärtl, Nils, Fabian Tatai, and Constantin A. Rothkopf. "Intuitive physical reasoning about objects’ masses transfers to a visuomotor decision task consistent with Newtonian physics." PLOS Computational Biology 16, no. 10 (October 19, 2020): e1007730. http://dx.doi.org/10.1371/journal.pcbi.1007730.
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While interacting with objects during every-day activities, e.g. when sliding a glass on a counter top, people obtain constant feedback whether they are acting in accordance with physical laws. However, classical research on intuitive physics has revealed that people’s judgements systematically deviate from predictions of Newtonian physics. Recent research has explained at least some of these deviations not as consequence of misconceptions about physics but instead as the consequence of the probabilistic interaction between inevitable perceptual uncertainties and prior beliefs. How intuitive physical reasoning relates to visuomotor actions is much less known. Here, we present an experiment in which participants had to slide pucks under the influence of naturalistic friction in a simulated virtual environment. The puck was controlled by the duration of a button press, which needed to be scaled linearly with the puck’s mass and with the square-root of initial distance to reach a target. Over four phases of the experiment, uncertainties were manipulated by altering the availability of sensory feedback and providing different degrees of knowledge about the physical properties of pucks. A hierarchical Bayesian model of the visuomotor interaction task incorporating perceptual uncertainty and press-time variability found substantial evidence that subjects adjusted their button-presses so that the sliding was in accordance with Newtonian physics. After observing collisions between pucks, which were analyzed with a hierarchical Bayesian model of the perceptual observation task, subjects transferred the relative masses inferred perceptually to adjust subsequent sliding actions. Crucial in the modeling was the inclusion of a cost function, which quantitatively captures participants’ implicit sensitivity to errors due to their motor variability. Taken together, in the present experiment we find evidence that our participants transferred their intuitive physical reasoning to a subsequent visuomotor control task consistent with Newtonian physics and weighed potential outcomes with a cost functions based on their knowledge about their own variability.
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Pfau, A., J. Schlienger, D. Rusch, A. I. Kalfas, and R. S. Abhari. "Unsteady Flow Interactions Within the Inlet Cavity of a Turbine Rotor Tip Labyrinth Seal." Journal of Turbomachinery 127, no. 4 (March 1, 2003): 679–88. http://dx.doi.org/10.1115/1.2008973.
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This paper focuses on the flow within the inlet cavity of a turbine rotor tip labyrinth seal of a two stage axial research turbine. Highly resolved, steady and unsteady three-dimensional flow data are presented. The probes used here are a miniature five-hole probe of 0.9 mm head diameter and the novel virtual four sensor fast response aerodynamic probe (FRAP) with a head diameter of 0.84mm. The cavity flow itself is not only a loss producing area due to mixing and vortex stretching, it also adversely affects the following rotor passage through the fluid that is spilled into the main flow. The associated fluctuating mass flow has a relatively low total pressure and results in a negative incidence to the rotor tip blade profile section. The dominating kinematic flow feature in the region between cavity and main flow is a toroidal vortex, which is swirling at high circumferential velocity. It is fed by strong shear and end wall fluid from the pressure side of the stator passage. The static pressure field interaction between the moving rotor leading edges and the stator trailing edges is one driving force of the cavity flow. It forces the toroidal vortex to be stretched in space and time. A comprehensive flow model including the drivers of this toroidal vortex is proposed. This labyrinth seal configuration results in about 1.6% turbine efficiency reduction. This is the first in a series of papers focusing on turbine loss mechanisms in shrouded axial turbines. Additional measurements have been made with variations in seal clearance gap. Initial indications show that variation in the gap has a major effect on flow structures and turbine loss.
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Hamdy, Omar, Mohamed Hssan Hassan Abdelhafez, Mabrouk Touahmia, Mohammed Alshenaifi, Emad Noaime, Khaled Elkhayat, Mohammed Alghaseb, and Ayman Ragab. "Simulation of Urban Areas Exposed to Hazardous Flash Flooding Scenarios in Hail City." Land 12, no. 2 (January 28, 2023): 353. http://dx.doi.org/10.3390/land12020353.
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According to the United Nations (UN), an additional 1.35 billion people will live in cities by 2030. Well-planned measures are essential for reducing the risk of flash floods. Flash floods typically inflict more damage in densely populated areas. The province of Hail encompasses 120,000 square kilometers, or approximately 6% of the total land area of the Kingdom of Saudi Arabia. Due to its innate physiographic and geologic character, Hail city is susceptible to a wide variety of geo-environmental risks such as sand drifts, flash floods, and rock falls. The aim of this work is to evaluate the rate of urban sprawl in the Hail region using remote sensing data and to identify urban areas that would be affected by simulated worst-case flash floods. From 1984 to 2022, the global urbanization rate increased from 467 to 713% in the Hail region. This is a very high rate of expansion, which means that the number of urban areas exposed to the highest level of flood risk is rising every year. With Gridded Surface Subsurface Hydrologic Analysis (GSSHA), a wide range of hydrologic scenarios can be simulated. The data sources for the soil type, infiltration, and initial moisture were utilized to create the coverage and index maps. To generate virtual floods, we ran the GSSHA model within the Watershed Modeling System (WMS) program to create the hazard map for flash flooding. This model provides a suitable method based on open access data and remote data that can help planners in developing countries to create the risk analysis for flash flooding.
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Sissons, Helen, and Thomas Cochrane. "Introducing Immersive Reality into the Journalism Curriculum." Pacific Journal of Technology Enhanced Learning 2, no. 1 (November 11, 2019): 7. http://dx.doi.org/10.24135/pjtel.v2i1.27.
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Following the introduction of the Google Cardboard virtual reality (VR) head mounted display (HMD) in 2014, mainstream journalism began exploring the potential of VR to transform news storytelling as an immersive experience (Lalwani, 2015; Somaiya, 2015). However, unlike the transformative impact of social media on journalism and journalism education (Mulrennan, 2017), VR has taken several years for this to filter into the curriculum of journalism higher education. AUT’s journalism programme includes a final semester, capstone, assessment in which students produce a piece of long-form immersive journalism that provides the opportunity to embed VR storytelling as an authentic immersive experience. To address this we created a collaborative curriculum design team in 2019 to design a workshop (Sissons & Cochrane, 2019) to introduce journalism students to the potential of VR to explore and create an immersive journalism experience. We used a design based research methodology (McKenney & Reeves, 2019) to structure the curriculum design process into four phases: initial analysis and exploration, development of a prototype curriculum intervention, evaluation and redesign of the intervention, and dissemination of identified design principles and findings. Meeting weekly the design team brainstormed a workshop that mapped the affordances of mobile XR to a real world project, and created a simple demonstration XR environment (https://seekbeak.com/v/kvPq47DpjAw). We founded the workshop design upon the principles of heutagogy (Blaschke & Hase, 2019), as the principles of heutagogy map closely to the core journalism graduate profile outcomes (Cochrane, Sissons, & Mulrennan, 2017). In this workshop students worked in teams to film and compile an interactive experience based on the University’s Journalism Media Centre, creating an interactive tour using SeekBeak (https://seekbeak.com). Using AUTEC ethics processes we obtained informed consent from the participating students for a feedback survey that will inform the second phase redesign of the curriculum design for 2020. Anonymous post-workshop student feedback survey responses, with a 78% return rate (https://www.surveymonkey.com/results/SM-5SMVCVSJ7/) were very positive. We believe this collaborative curriculum design approach provides a simple model that can be utilised in other higher education discipline contexts.
References
Blaschke, L. M., & Hase, S. (2019). Heutagogy and digital media networks: Setting students on the path to lifelong learning. Pacific Journal of Technology Enhanced Learning, 1(1), 1-14. doi:https://doi.org/10.24135/pjtel.v1i1.1
Cochrane, T., Sissons, H., & Mulrennan, D. (2017). Mainstreaming Mobile Learning in Journalism Education. In H. Crompton & J. Traxler (Eds.), Mobile Learning in Higher Education: Challenges in Context (pp. 19-30). New York: Routledge.
Lalwani, M. (2015). ABC News introduces VR initiative with 360-degree tour of Syria. Retrieved from http://www.engadget.com/2015/09/17/abc-news-introduces-vr-initiative-with-360-degree-tour-of-syria/
McKenney, S., & Reeves, T. (2019). Conducting educational design research (2nd ed.). London: Routledge.
Mulrennan, D. (2017). Mobile Social Media and the News: Where Heutagogy Enables Journalism Education. Journalism & Mass Communication Educator, OnlineFirst(0), 1-12. doi:10.1177/1077695817720762
Sissons, H., & Cochrane, T. (2019). Newsroom Production: XRJournalism Workshop. Retrieved from https://tinyurl.com/XRJournalism
Somaiya, R. (2015, 20 October 2015). The Times partners with Google on virtual reality project. Retrieved from http://www.nytimes.com/2015/10/21/business/media/the-times-partners-with-google-on-virtual-reality-project.html?smid=tw-nytimestech&smtyp=cur&_r=1
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Chardey, Elia Kodjo, Rosamaria Fastuca, Matteo Beretta, Alberto Di Blasio, Nicolò Vercellini, Alberto Caprioglio, Piero Antonio Zecca, and Aldo Macchi. "Digital Dynamic 3D Monitoring of Lower Incisors Intrusion in Lingual Orthodontics." Open Dentistry Journal 12, no. 1 (January 31, 2018): 104–17. http://dx.doi.org/10.2174/1874210601812010104.
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Objective: The aim of the present study is to propose a 3-dimensional evaluation of lower intrusion obtained with lingual orthodontics considering not only the crowns but also dental roots. Methods: 9 adult patients underwent fixed lingual orthodontic treatment with i-TTя lingual brackets system for the correction of crowding in the lower arch associated with a deep overbite. Initial records, consisting of photos, CBCTs and intraoral scans were collected. Threshold segmentation of the CBCT was performed to generate a three-dimensional virtual model of each the teeth of the lower arch, superimposed with the crown of the same teeth obtained by intraoral scan models to generate a complete set of digital composite lower arch The same procedure was performed to monitor one key step of the i-TTЯ technique consisting in lower incisors intrusion (T2). T1-T2 three-dimensional superimposition and color displacement maps were generated to measure and evaluate the movements obtained at the lower arch. Results: The root displacement of the incisors during their intrusion in the early stage was totally “bone-safe” in the 88.9% (8 of 9) of the cases observed. No significant extrusion of the premolars used as anchorage unit was measured. Conclusion: This method has proved to be an accurate and reliable approach to dynamically visualize the 3-dimensional positions of the teeth, including their roots, with no additional radiation for in-progress treatment monitoring. The 3-dimensional evaluation showed that the employed lingual appliance allowed to obtain significant lower incisors intrusion with negligible undesired extrusion of premolars employed as anchorage teeth.
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Rae Nelson, Cassidy, Joseph Conwell, Samuel Lally, Madelyn Cohn, Kyle Tanous, Jason Moats, and Joseph L. Gabbard. "Exploring Augmented Reality Triage Tools to Support Mass Casualty Incidents." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 66, no. 1 (September 2022): 1664–66. http://dx.doi.org/10.1177/1071181322661337.
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ARTTS is a head-worn Augmented Reality (AR) Triage Tool Suite containing an initial sorting tool, virtual assessment tool, and virtual triage tag to assist first responders in mass casualty incidents. The initial sorting tool prompts stunned responders through first-wave tasks to aid recalibration from shock to triage. The virtual assessment tool provides novice responders, potentially confused by the chaos, with a walkthrough of the SALT triage flowchart. Finally, current emergency medical triage processes leverage static paper tags susceptible to loss or illegible damage. ARTTS’ virtual triage tags are dynamic, can be updated automatically with vital sensors or manually through responder interaction, and employ user interface emergent features based on individual patient conditions. This paper describes the UX process used to develop ARTTS.
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Kattel, Parameshwari, Khim B. Khattri, and Shiva P. Pudasaini. "A multiphase virtual mass model for debris flow." International Journal of Non-Linear Mechanics 129 (March 2021): 103638. http://dx.doi.org/10.1016/j.ijnonlinmec.2020.103638.
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Esat, Ibrahim I., and Neviman Ozada. "Articular human joint modelling." Robotica 28, no. 2 (December 7, 2009): 321–39. http://dx.doi.org/10.1017/s0263574709990592.
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SUMMARYThe work reported in this paper encapsulates the theories and algorithms developed to drive the core analysis modules of the software which has been developed to model a musculoskeletal structure of anatomic joints. Due to local bone surface and contact geometry based joint kinematics, newly developed algorithms make the proposed modeller different from currently available modellers. There are many modellers that are capable of modelling gross human body motion. Nevertheless, none of the available modellers offer complete elements of joint modelling. It appears that joint modelling is an extension of their core analysis capability, which, in every case, appears to be musculoskeletal motion dynamics. It is felt that an analysis framework that is focused on human joints would have significant benefit and potential to be used in many orthopaedic applications. The local mobility of joints has a significant influence in human motion analysis, in understanding of joint loading, tissue behaviour and contact forces. However, in order to develop a bone surface based joint modeller, there are a number of major problems, from tissue idealizations to surface geometry discretization and non-linear motion analysis. This paper presents the following: (a) The physical deformation of biological tissues as linear or non-linear viscoelastic deformation, based on spring-dashpot elements. (b) The linear dynamic multibody modelling, where the linear formulation is established for small motions and is particularly useful for calculating the equilibrium position of the joint. This model can also be used for finding small motion behaviour or loading under static conditions. It also has the potential of quantifying the joint laxity. (c) The non-linear dynamic multibody modelling, where a non-matrix and algorithmic formulation is presented. The approach allows handling complex material and geometrical nonlinearity easily. (d) Shortest path algorithms for calculating soft tissue line of action geometries. The developed algorithms are based on calculating minimum ‘surface mass’ and ‘surface covariance’. An improved version of the ‘surface covariance’ algorithm is described as ‘residual covariance’. The resulting path is used to establish the direction of forces and moments acting on joints. This information is needed for linear or non-linear treatment of the joint motion. (e) The final contribution of the paper is the treatment of the collision. In the virtual world, the difficulty in analysing bodies in motion arises due to body interpenetrations. The collision algorithm proposed in the paper involves finding the shortest projected ray from one body to the other. The projection of the body is determined by the resultant forces acting on it due to soft tissue connections under tension. This enables the calculation of collision condition of non-convex objects accurately. After the initial collision detection, the analysis involves attaching special springs (stiffness only normal to the surfaces) at the ‘potentially colliding points’ and motion of bodies is recalculated. The collision algorithm incorporates the rotation as well as translation. The algorithm continues until the joint equilibrium is achieved. Finally, the results obtained based on the software are compared with experimental results obtained using cadaveric joints.
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González-Rojí, Santos J., Sheila Carreno-Madinabeitia, Jon Sáenz, and Gabriel Ibarra-Berastegi. "Changes in the simulation of atmospheric instability over the Iberian Peninsula due to the use of 3DVAR data assimilation." Hydrology and Earth System Sciences 25, no. 6 (June 18, 2021): 3471–92. http://dx.doi.org/10.5194/hess-25-3471-2021.
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Abstract. The ability of two downscaling experiments to correctly simulate thermodynamic conditions over the Iberian Peninsula (IP) is compared in this paper. To do so, three parameters used to evaluate the unstable conditions in the atmosphere are evaluated: the total totals index (TT), convective available potential energy (CAPE), and convective inhibition (CIN). The Weather and Research Forecasting (WRF) model is used for the simulations. The N experiment is driven by ERA-Interim's initial and boundary conditions. The D experiment has the same configuration as N, but the 3DVAR data assimilation step is additionally run at 00:00, 06:00, 12:00, and 18:00 UTC. Eight radiosondes are available over the IP, and the vertical temperature and moisture profiles from the radiosondes provided by the University of Wyoming and the Integrated Global Radiosonde Archive (IGRA) were used to calculate three parameters commonly used to represent atmospheric instability by our own methodology using the R package aiRthermo. According to the validation, the correlation, standard deviation (SD), and root mean squared error (RMSE) obtained by the D experiment for all the variables at most of the stations are better than those for N. The different methods produce small discrepancies between the values for TT, but these are larger for CAPE and CIN due to the dependency of these quantities on the initial conditions assumed for the calculation of a lifted air parcel. Similar results arise from the seasonal analysis concerning both WRF experiments: N tends to overestimate or underestimate (depending on the parameter) the variability of the reference values of the parameters, but D is able to capture it in most of the seasons. In general, D is able to produce more reliable results due to the more realistic values of dew point temperature and virtual temperature profiles over the IP. The heterogeneity of the studied variables is highlighted in the mean maps over the IP. According to those for D, the unstable air masses are found along the entire Atlantic coast during winter, but in summer they are located particularly over the Mediterranean coast. The convective inhibition is more extended towards inland at 00:00 UTC in those areas. However, high values are also observed near the southeastern corner of the IP (near Murcia) at 12:00 UTC. Finally, no linear relationship between TT, CAPE, or CIN was found, and consequently, CAPE and CIN should be preferred for the study of the instability of the atmosphere as more atmospheric layers are employed during their calculation than for the TT index.
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Bernard, A. "Virtual engineering: Methods and tools." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 219, no. 5 (May 1, 2005): 413–21. http://dx.doi.org/10.1243/095440505x32238.
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This paper presents an overview of actual approaches in virtual engineering, mainly from the design point of view. The evolution of the market has necessitated the reduction of time-to-market, essentially because the product life cycle is shorter, but also because it is very important to proceed more rapidly from an initial conception to a mass production object. As a result of newly evolved software DOI: environments, knowledge-based systems, and product data management, processes for integrated design and manufacturing for new products have emerged. Owing to this evolution of virtual engineering technologies, it has become possible today to validate parts representative of mass production within a very short time. This paper provides an overview of the actual methods and tools in all the components that affect the speed and efficiency of product development, in particular all the possibilities available to the designer, from the earliest stages of a product's life cycle.
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Xu, Wen, Yong Wang, Weimin Huang, and Yuping Duan. "An Efficient Nonlinear Mass-Spring Model for Anatomical Virtual Reality." IEEE Transactions on Instrumentation and Measurement 71 (2022): 1–10. http://dx.doi.org/10.1109/tim.2022.3164132.
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Wang, Yu, Shuxiang Guo, and Baofeng Gao. "Vascular elasticity determined mass-spring model for virtual reality simulators." International Journal of Mechatronics and Automation 5, no. 1 (2015): 1. http://dx.doi.org/10.1504/ijma.2015.068446.
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Parés, Narcis, and Roc Parés. "Towards a Model for a Virtual Reality Experience: The Virtual Subjectiveness." Presence: Teleoperators and Virtual Environments 15, no. 5 (October 1, 2006): 524–38. http://dx.doi.org/10.1162/pres.15.5.524.
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After analyzing how VR experiences are modeled within human computer interaction (CHI) we have found there is a deep theoretical gap. Similarly to how the scientific community has defined CHI models for multimedia applications, it would be very important to have such models for VR—obviously the standpoint cannot be the same because multimedia and VR applications differ in essence. Indeed, there is no formal model to unify the way in which scientists and designers of VR applications define their experiences. More specifically, apart from the isolated initial scheme defined by S.R. Ellis (Ellis, 1991, Computing Systems in Engineering, 2(4) 321–347; Ellis, 1993, Pictorial Communication in Virtual and Real Environment, 3–11), and a low level model defined by Latta and Oberg (Latta & Oberg, 1994, IEEE Computer Graphics & Applications, 14, 23–29), there is no model to fully describe the relationship with which the user will be experiencing the VR application. In this paper we shall explain where exactly we think this gap is found, which elements and concepts are involved in the definition of a model of experience, and finally propose a definition of a model that we think, eventually, will fill this gap.
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Saputro, Wahyu Adhi, and Fachruddin Edi Nugroho Saputro. "Program Agroschooling pada Siswa Sekolah Dasar SD 01 Manang untuk Meningkatkan Minat terhadap Bidang Pertanian." Indonesian Journal of Community Services 2, no. 1 (May 31, 2020): 68. http://dx.doi.org/10.30659/ijocs.2.1.68-79.
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AbstrakJumlah penduduk yang semakin meningkat diikuti dengan selarasnya kebutuhan pangan namun tidak diikuti dengan peningkatan sektor pertanian di Indonesia ditunjukkan dengan semakin berkurangnya minat anak muda di bidang pertanian. Permasalahan mengenai penurunan minat anak muda di pertanian hakikatnya menjadi perhatian khusus dari berbagai pihak karena menjadi faktor penghambat pertumbuhan pembangunan pertanian. SD Negri 01 Manang merupakan mitra yang tepat untuk diberikannya kurikulum pendidikan anak yang diselipkan arti penting pertanian sehingga dari masa kanak-kanak potensi pertanian untuk masa depan tertanam dalam pola pikir mereka. Solusi mengenai model edukasi pertanian sejak dini dirasa sangat tepat menarik minat anak-anak dan disesuaikan dengan kebutuhan, kemampuan dan kesenangan setiap anak sehingga dampaknya dapat meminimumkan dampak ketidaktertarikan generasi muda terhadap bidang pertanian. Program Agroschooling memiliki tujuan untuk mengenalkan kepada anak-anak sekolah dasar mengenai pentingnya dunia pertanian dan pengelolaan lingkungan alam sekitar. Metode yang diberikan dalam program agroschooling anak-anak SD menonton secara virtual video tentang pertanian, kemudian ditanyai dengan beberapa pertanyaan di kuesioner dengan bantuan mahasiswa mengenai cita-cita dan kesukaan di bidang pertanian. Acara dilanjutkan dengan penanaman tanaman di ikuti dengan pertanyaan kuesioner untuk menanyai apakah ada yang ingin berganti cita-cita setelah mengikuti program Agrochooling. Data-data tersebut di analisis menggunakan linkert dan diinputkan dalam rating scale. Selain itu digunakan analisis before dan after untuk melihat peningkatan anak-anak yang ingin bekerja di sektor pertanian sebelum dan sesudah diadakan program Agroshcooling. Survei awal membuktikan bahwa sebanyak 0% dari siswa dan siswi SD yang bercita-cita ingin bekerja di sektor pertanian. Peningkatan persentase keinginan bekerja para siswa dan siswi di SD 01 Manang di bidang pertanian terjadi sebanyak 15,38% setelah diadakannya program Agroschooling. Persepsi para siswa dan siswi terhadap kegiatan pengabdian kepada masyarakat mengenai agroschooling masuk ke dalam kategori� baik. Harapannya akan adanya kelanjutan pengabdian dengan survey ketertarikan siswa terhadap pertanian. �Kata kunci: Pertanian; Agroschooling�AbstractIncreasing population followed by harmonious food needs but not followed by an increase in the agricultural sector in Indonesia is shown by the decreasing interest of young people in agriculture. The problem regarding the decline of young people's interest in agriculture is of particular concern to various parties because it is a factor inhibiting the growth of agricultural development. SD Negri 01 Manang is the right partner for child education curriculum which is tucked in the importance of agriculture so that from childhood childhood the potential of agriculture for the future is embedded in their mindset. The solution regarding the agricultural education model from the beginning is felt to be very appropriate to attract the interests of children and adapted to the needs, abilities and enjoyment of children so that the impact can minimize the impact of the young generation's disinterest in agriculture. The method given in the agroschooling program for elementary school children watched a virtual video about agriculture, then was asked a number of questions in the questionnaire with the help of students about their ideals and preferences in agriculture. The program was followed by planting plants followed by questionnaire questions to ask if anyone wanted to change their goals after joining the Agrochooling program. The data is analyzed using linkert and entered in the rating scale. Also used before and after analysis to see the increase in children who want to work in the agricultural sector before and after the Agroshcooling program was held. The Agroschooling Program aims to introduce elementary school children about the importance of agriculture and the management of the surrounding natural environment. Initial survey prove that as many as 0% of elementary school students want to work in the agricultural sector. The increase in the percentage of students wanting to work at SD 01 Manang in agriculture occurred as much as 15.38%. The perception of students and students of community service activities regarding agroschooling into the good category. The hope is that there will be continued service by surveying student�s interest in agriculture �Keywords: Agriculture; Agroschooling
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McWhorter, Rochell R., and Susan A. Lynham. "An Initial Conceptualization of Virtual Scenario Planning." Advances in Developing Human Resources 16, no. 3 (May 5, 2014): 335–55. http://dx.doi.org/10.1177/1523422314532096.
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The Problem Recent disruptive events introduced high volatility and uncertainty into the contemporary organizational environment whereby well-established organizations found scenario planning (SP) useful to craft strategy. However, because SP is typically a very costly endeavor, it is less accessible to new startups, small businesses, nonprofits, and large-scale organizations that could greatly benefit. The Solution We propose an initial conceptual model whereby sophisticated technologies that typically enable virtual events be utilized to facilitate virtual SP activities for real-time participation from geographically disbursed locations reducing expenses and providing access to one of human resource development’s (HRD’s) strategic learning tools. We posit that HRD professionals be involved in planning and implementation through the scope of technology development within the context of virtual HRD. The Stakeholders This article provides researchers and scholar-practitioners with a conceptualization of current thinking around the notion of utilizing technology to create an online environment conducive for SP. This article will be of particular interest to those involved in formulating organizational strategy including those where costs of face-to-face SP and other forms of strategic initiatives are either time or cost prohibitive.