bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generative Adversarial Design Analysis of Non-Convexity in Topology Optimization
Authors: Hertlein Nathan , Gillman Andrew , Buskohl Philip R. 
Published: November 2022

Abstract
Material penalization and filtering schemes are key strategies applied to topology optimization (TO) to promote more discrete and manufacturable designs. However, these modifications introduce fluctuations in the design landscape that amplify non-convexity and influence the local minima identified by TO. Harnessing the machine learning approach of generative adversarial networks (GAN), we investigate the role of penalization and filtering by comparing the designs between TO and GAN-based TO surrogates. A total of 17 GANs were constructed to predict 2D minimum compliance topologies across a set of penalization factors and filters, each interpolating a design space of 270,000 boundary condition and loading scenarios. The prevalence of GAN-predicted topologies with better compliance than TO-calculated topologies was estimated via a random sampling of the design space. GAN ‘over-performance’ occurs across material penalization and filtering conditions, where the frequency tends to increase as penalization increases. Analysis of this test set is leveraged to highlight trends regarding the conditions under which this ‘over-performance’ occurs, and the geometric characteristics these designs exhibit. Collectively, this study presents an alternative method to characterize the effects of penalization and filtering on design outcomes and motivates the use of data-driven surrogates to augment traditional approaches.
Virtual Reality for Delivering Swimming Practice Through Water-Free Immersive Training System
Authors: Li Shuo , Zheng Hongtao , Yuan Wenyu , Han Ting 
Published: November 2022

Abstract
Learning to swim is essential at any age as a great way to exercise and part of safety measures. Not everyone feels comfortable to start practicing from being in the water due to specific psychological or physical difficulties. Similarly, the in-water practice lacks real-time feedback for postures or stroke corrections. However, Virtual Reality (VR) technology presents a great potential to enable a water-free approach as preparation for, or supplementary to, in-water practice. Such technology is still under-explored. This paper proposes a Water-Free Immersive Training System (WITS) which verifies the feasibility of a Water-free Immersive Training System using system construction and experience tests. WITS features whole-body physical feedback (e.g.through distributed resistance materials or controllable air cushions) and body movement tracking to provide visual and embodied immersion and real-time training feedback. A Presence Questionnaire (PQ) is adopted to analyze users immersive experience. This paper discusses the user experience of WITS and the broader directions and implications for future development. This paper is intended to propose a novel design application and expand the possibility of other innovative forms of immersive sports. At the same time, it provides a set of design-oriented insights for creating tangible immersive experiences in VR systems.
Topology Optimization of Permanent Magnets for Generators Using Level Set Methods
Authors: Tian Jiawei , Zhuang Ran , Cilia Juan , Rangarajan Arvind , Luo Fang , Longtin Jon , Chen Shikui 
Published: November 2022

Abstract
Generators are considered as the core application of electromagnetic machines, which require high-cost rare-earth-based permanent magnets. The development of generators is moving toward high efficiency and increased environmental friendliness. Minimizing the use of rare earth materials such as magnetic materials under the premise of machine performance emerges as a challenging task. Topology optimization has been promisingly applied to many application areas as a powerful generative design tool. It can identify the optimal distribution of magnetic material in the defined design space. This paper employs the level-set-based topology optimization method to design the permanent magnet for generators. The machine under study is a simplified 2D outer rotor direct-drive wind power generator. The dynamic and static models of this generator are studied, and the magnetostatic system is adopted to conduct the topology optimization. The optimization goals in this study mainly focused on two aspects, namely the maximization of the system magnetic energy and the generation of a target magnetic field in the region of the air gap. The continuum shape sensitivity analysis is derived by using the material time derivative, the Lagrange multiplier method, and the adjoint variable method. Two numerical examples are investigated, and the effectiveness of the proposed design framework is validated by comparing the performance of the original design against the optimized design.
Design and Research of Intelligent QA System for Flight Crew Operating Manual
Authors: Tan Xin , Zhong Jingshu , Jin Yu , Liang Yan , Zheng Yu , Liu Ying 
Published: November 2022

Abstract
Aviation flight crews rely on a large number of complex standard documents and operation manuals when performing flight tasks. In order to relieve the pressure of manual retrieval of documents, intelligent question-answering technology based on reading comprehension is gradually applied. In this paper, the flight crew operation manual SQuAD dataset is studied and built, based on which the reader-retriever framework of text content-based reading question answering system (TCQA) is analyzed and established. Experiments are conducted to compare the relevant indexes of the QA system with different combinations of reader and retriever models under the open-source tool haystack. Based on the comparison of response speed and retrieval capability, the best model combination is obtained for the flight crew operation manual dataset, and suggestions are made for the model-related performance improvement.
Natural Language Processing for Content Analysis of Communication in Collaborative Design
Authors: Lokesh Sachin H. , Chaudhari Ashish M. , Thekinen Joseph , Panchal Jitesh H. 
Published: November 2022

Abstract
We address the problem of content analysis in text-based engineering design communication. Existing methods to characterize communication content in engineering design are manual or qualitative, which is tedious for large datasets. We formulate the characterization of communication messages as an intent classification task. We identify two intents — Intent 1 captures the presence and flow of information, Intent 2 captures specific topics about design parameters and objectives. We compare the predictive accuracy of convolutional LSTM, character-based convolutional LSTM, XLNet, and BERT models for the intent classification task. The results of our comparison show that the XL-Net model predicts Intents 1 and 2 with 88% and 81% accuracy, respectively, on text data collected from 40 teams in a design experiment with university students. We analyze the differences in communication patterns between high- and low-performing teams. Time-series studies show that high-performing teams have more responsive communication and a higher consistency of information exchange.
QuickProbe: Quick Physical Prototyping-in-Context Using Physical Scaffolds in Digital Environments
Authors: Raina Abhijeet Singh , Vyas Shantanu , Ebert Matthew , Krishnamurthy Vinayak R. 
Published: November 2022

Abstract
In this paper, we introduce a novel prototyping workflow, QuickProbe, that enables a user to create quick-and-dirty prototypes taking direct inspiration from existing physical objects. Our workflow is inspired by the notion of prototyping-in-context using physical scaffolds in digital environments. To achieve this we introduce a simple kinesthetic-geometric curve representation wherein we integrated the geometric representation of the curve with the virtual kinesthetic feedback. We test the efficacy of this kinesthetic-geometric curve representation through a qualitative user study conducted with ten participants. In this study, users were asked to generate wire-frame curve networks on top of the physical shapes by sampling multiple control points along the surface. We conducted two different sets of experiments in this work. In the first set of experiments, users were tasked with tracing the physical shape of the object. In the second set of experiments, the goal was to explore different artistic designs that the user could draw using the physical scaffolding of the shapes. Through our user studies, we showed the variety of designs that the users were able to create. We also evaluated the similarities and differences we observed between the two different sets of experiments. We further discuss the user feedback and the possible design scenarios where our QuickProbe workflow can be used.
In-Process Data Integration for Laser Powder Bed Fusion Additive Manufacturing
Authors: Perisic Milica , Lu Yan , Jones Albert 
Published: November 2022

Abstract
Additive manufacturing (AM) is a powerful technology that can create complex metallic parts and has the potential to improve the economic bottom line for various industries. However, due to process instabilities, and the resulting material defects that impact the part quality, AM still isn’t as widely used as it could be. To overcome this situation, it is crucial to develop an environment for easy, in-process monitoring and real-time control to detect process anomalies and predict part defects as quickly as possible. AM in-process monitoring measures various process variables and the sensors generate large volumes of structured or unstructured, 1D, 2D, and 3D data, some of which are acquired at very high frequencies. Integration of such data and their analysis are necessary for effective in-process monitoring and real-time control, but they are facing many challenges due to the characteristics of AM in-process data. This paper provides an overview of different in-process monitoring data sources and their connection methods and addresses the integration issues associated with acquiring and fusing the data for both on-fly control and offline analysis. The paper also presents a guideline to help high-speed data integration. This guideline can help users to decide the best data-integration configuration for a specific use case.
Controlling Microwave Energy Deposition Using Active Plasma Elements for Material Processing Applications
Authors: Graber Benjamin D. , Iliopoulos Athanasios P. , Michopoulos John G. , Steuben John C. , Apetre Nicole A. , Petrov George M. , Johnson Luke A. , Fischer Richard P. , Gorzkowski Edward P. , Patterson Eric A. 
Published: November 2022

Abstract
This work is motivated by the need to modulate microwave beam propagation, phase, shape, and direction using an array of plasma elements. Tailoring microwave beams in this fashion will enable new material processing capabilities such as induced localized heating. An initial process example consists of a cylindrical plasma element inserted into a waveguide between a microwave radiation source and a material of interest. In order to establish the feasibility of the proposed process, an accurate model of an argon mercury plasma including plasma-microwave coupling was developed and described herein. Both microwave plasma heating and magnetic plasma couplings are considered. The required computational framework was implemented within the COMSOL Multiphysics finite element solver. The model is first used to investigate a 2D geometry, before being extended to a 3D geometry. The obtained solutions of the relevant partial differential equations and the associated predictions increased the understanding of the interplay between plasma and electromagnetic properties under consideration in the model. Model implementation confirms that a plasma element can be used to modulate incident microwave radiation, thereby shaping the transmitted beam. The framework also enables analysis of beam shaping techniques under consideration for material processing of ceramics. For ceramic processing, beam shaping techniques are being used to direct microwave radiation to predictable, localized areas in order to sinter the dielectric powders under consideration.
Active Pressure Pulsation Suppression Method by Parallel-Series Structure in DFCU Based on Variable Step Size FXLMS Algorithm
Authors: Yao Jing , Cheng Yuwang , Wang Pei , Zhao Juntao , Wang Yupeng 
Published: November 2022

Abstract
Pressure pulsation is the challenge in digital hydraulics owing to its switching characteristics, which makes control performance worse. This study proposed the parallel-series structure for active pressure pulsation suppression, based on variable step size FXLMS algorithm. The pressure pulsation performance in DFCU is analyzed under PNM and PWM control for better suppression effect. On this basis, the active pressure pulsation suppression control algorithm is designed utilizing the principle of pressure wave destructive interference, so that the reverse pressure pulsation generated by the parallel-series structure, including an in-series valve arranged in line between the DFCU and the load and a by-pass valve arranged in parallel with DFCU, offsets with the pressure pulsation at the load end. The adaptive FXLMS algorithm with variable step size is used to identify the secondary path online for better effect of pressure pulsation suppression and achieve the “alignment” between the reverse pressure signal and the initial pressure signal. The experimental results show it can suppress pressure pulsation by 79%, 54%, 37% and 29% at 10 Hz, 30 Hz, 50 Hz, 70 Hz for single valve and 77% for DFCU. It has been demonstrated that the proposed structure has significant effect and guiding relevance for pressure pulsation suppression of DFCU.
Optimizing Viscosity for Maximum Power in a Hydrostatic Transmission Wind Turbine
Authors: Chen Justin , Mohanty Biswaranjan , Escobar-Naranjo Daniel , Stelson Kim A. 
Published: November 2022

Abstract
In basic hydraulic theory, efficiency is dependent on volumetric and mechanical losses. Components dominated by mechanical losses favor low viscosity fluids, while those dominated by volumetric losses favor high viscosity fluids. For a hydrostatic transmission (HST), efficiency of both the pump and motor must be considered. The goal of this work is to model the HST viscosity-efficiency curve for finding the optimal viscosity and to validate the results with experiments. This paper reports on preliminary results with only partial success.
This study uses a mathematical efficiency model that is dependent on non-dimensional viscosity, two non-dimensional length ratios, and fractional swash plate displacement. Rather than using physical dimensions for the non-dimensional length ratios, these parameters were determined for the pump and motor through constant viscosity experiments. The predicted results of the model were compared to validation experiments where viscosity was varied by changing temperature.
Results showed high accuracy for the pump model at all tested conditions, but the accuracy of the motor model was lacking, deviating significantly from experiments at low viscosities. For future studies, it is recommended to increase the number of data points at low dimensionless viscosity to create a more accurate model fit. Alternative models that provide more realistic results will be considered.
Design and Simulation Analysis of a Pump-Controlled Actuation System for Heavy-Duty Booms
Authors: Han Xu , Leinonen Manu , Minav Tatiana 
Published: November 2022

Abstract
The electrified pump-controlled hydraulics receives increasing attention from both industry and academia. Its combined advantages of hydraulic and electric actuators result in an expanding application in heavy-duty actuation. One example of such actuation application is the boom. Despite the diverse achievements from academia, the commercial application has not started yet. This is partially caused by the absence of the auxiliary functions of the conventional hydraulic actuation, e.g. thermal management, filtration, and maintenance convenience, in proposed academic solutions. This paper proposes a new design of the pump-controlled actuation solution for heavy-duty booms, which takes both the primary and auxiliary function requirements into consideration. Then, the proposed system is modeled and simulated using a crane study case, which requires 50 kW power for moving each axis. The primary functions, e.g. the control performance, the energy efficiency, and the auxiliary functions are both analyzed. The control methods are proposed for supporting the upper-level control modes. A conventional load sensing actuation system is also simulated as a comparison. The simulation results demonstrated around 40–70 % energy-saving advantages and comparable auxiliary functions of the proposed system over the conventional system. The achieved results prove the applicability of the proposed system and promote the application of the pump-controlled actuation in heavy-duty booms.
Accumulator Sizing for the Hybrid Hydraulic Electric Architecture (HHEA) Using Dynamic Programming
Authors: Wills Jackson , Li Perry Y. 
Published: November 2022

Abstract
The Hybrid Hydraulic Electric Architecture (HHEA) is an approach to electrifying and improving that does not require very large electric machines. The majority power is provided hydraulically via a set of common pressure rails while small electric machines are used to modulate that power to meet exact demand. Each common pressure rail has an accumulator, which keeps the pressure of each rail near constant as long as the volume in the accumulator does not change much. A main pump adds or removes fluid from each accumulator as needed to reduce volume changes in the accumulators. It is the operation of this main pump which is investigated here.
In previous analysis it was assumed that the size of the accumulators was large enough to account for any difference in fluid volume without significantly changing the pressure. In this paper, the required accumulator sizes are studied using a dynamic programming approach. At each time step the inlet and outlet of the main pump could be connected to any of the common pressure rails. These decisions for the main pump were optimized to minimize the required accumulator size.
Case studies are conducted using drive cycles from a 22-ton excavator, a 20-ton wheel loader and a 5-ton excavator. The machines could be operated with total accumulator sizes of less than 20, 10, and 5 liters respectively. Required accumulator size was found to vary with pump flow rate, the frequency at which the pump/motor was able to change operating conditions, the tolerance level of pressure deviation and the accumulator’s polytropic index.
A Set of Benchmark Problems for Fluid Power System Simulation
Authors: Manhartsgruber Bernhard 
Published: November 2022

Abstract
Mathematical modelling and simulation have become widespread tools in the fluid power industry. The sheer number of available software packages of commercial and academic nature as well as the abundance of published modeling strategies for certain components gives multiple possibilities for modeling one and the same fluid power system. The mathematical model is required to capture the behavior of the real system with a certain degree of accuracy while using a minimum of computational resources for reaching this goal. This trade-off cannot be assessed by looking on model complexity on the level of differential equations only. The computational efficiency is defined by the combination of mathematical modelling on the high level of differential equations, the choice of a solver, i.e. the time discretization, and the details of software implementation like the optimized compilation of right hand sides for the solvers. In order to compare different modeling strategies on various software platforms, well defined benchmark problems are needed. This paper presents a first attempt towards such a set of benchmark problems targeted at the specific problems of fluid power simulation. In a first benchmark case, a system with reversing flow at an orifice under the additional difficulty of a stiff differential equation system is presented. A second benchmark case uses the coupling between dry friction in a hydraulic cylinder and wave propagation in a transmission line which has been shown to give notorious modelling problems in the literature. The goal of the present publication is to present a proposal for such benchmark systems in order to make the accuracy and computational performance of simulation approaches more comparable.
An Electric-Hydraulic Hybrid Wheel Loader With Mode-Driven Control Strategy
Authors: Wu Zihan , Wang Feng , Xu Bing , Fiebig Wieslaw 
Published: November 2022

Abstract
The powertrain electrification is an effective solution to emission reduction of mobile machines. To overcome the low power density of electric drive, a hydraulic accumulator is introduced as a supplementary power source. In this paper an electric-hydraulic hybrid powertrain solution is studied for wheel loader propulsion system, where it combines the energy density of electric drive and high power density of hydraulic drive. The energy management strategy is essential for hybrid powertrain since it determines how efficiently the power is transferred between different energy sources. In this paper a mode-driven control strategy for electric-hydraulic hybrid wheel loader is proposed to achieve electric power reduction over power follower strategy (baseline strategy), without sacrificing electric energy use and vehicle operation hours. In the strategy four modes are defined and the expected hydraulic SOC (system pressure) profile in each mode is scheduled to provide supplementary power assist and capture regenerative braking energy. By setting the pressure profile, the hydraulic charge sustaining is guaranteed. The system operation with mode-driven strategy is compared with power follower strategy through simulation studies. Results show that peak powers of battery and electric motor with mode-driven strategy are reduced by nearly 30% compared to power follower strategy. Results also show that the vehicle operation hour has been slightly increased by 3% by using mode-driven strategy. These results verify the effectiveness of proposed strategy for electric-hydraulic hybrid wheel loader.
Further considerations about the traversability of thin-shell wormholes
Authors: de Celis E. Rubín , Simeone C. 
Published: November 2022

AbstractTraversability in relation with tides in thin-shell wormholes is revisited to investigate the possibility of improving recently noted restrictive conditions for a safe travel across a wormhole throat. We consider wormholes mathematically constructed starting from background geometries which are solutions of scalar–tensor theories as dilaton gravity and Brans–Dicke gravity. The advantages of working within such frameworks are studied by examining the dependence of the extrinsic curvature and tides at the throat with the parameters determining the departure from pure relativity; the associated behaviour of tides in the smooth regions of the geometries is also analyzed. Other related but different approaches within pure relativity are discussed in the appendices.
Lattice studies of supersymmetric gauge theories
Authors: Schaich David 
Published: November 2022

AbstractSupersymmetry plays prominent roles in the study of quantum field theory and in many proposals for potential new physics beyond the standard model. Lattice field theory provides a non-perturbative regularization suitable for strongly interacting systems. This invited review briefly summarizes significant recent progress in lattice investigations of supersymmetric field theories, as well as some of the challenges that remain to be overcome. I focus on progress in three areas: supersymmetric Yang–Mills (SYM) theories in fewer than four space-time dimensions, as well as both minimal$${\mathcal {N}} = 1$$N=1SYM and maximal$${\mathcal {N}} = 4$$N=4SYM in four dimensions. I also highlight superQCD and sign problems as prominent challenges that will be important to address in future work.