bluuebunny/crossref_metadata_2025 huggingface dataset:
Faire faire ou faire avec ?
Authors: Martin Christine , Lemaitre Christine Noël
Published: June 2023

La fonction du manager est circonscrite dès son origine dans l’idée de faire faire aux autres. Ainsi le manager est avant tout celui qui doit « prendre en main », c’est-à-dire à la fois motiver, contrôler et encadrer l’activité des membres de son équipe. Porteurs des modes d’organisations et chargés de leurs mises en œuvre, les managers peuvent se retrouver eux-mêmes victimes de ces modèles et sont souvent les premières victimes des risques psychosociaux. Dans ce contexte n’est-il pas temps d’imaginer un management qui ne surplombe pas le travail mais qui le comprenne réellement et parte du travail réel des différents protagonistes ? Cela est-il possible ? Et comment penser le travail managérial lui-même ? Cette contribution propose une nouvelle conception du management intégrant les analyses formulées par les approches critiques francophones développées par des chercheurs en sciences humaines et sociales, analyses reprises et prolongées par l’ergologie. En effet, la vision du travail portée par l’ergologie induit une vision alternative du management, qui n’impliquerait plus simplement de « faire faire aux autres » mais plutôt de « faire avec les autres » c’est-à-dire coconstruire le sens à donner à son travail, à l’organisation à laquelle on appartient et au vivre-ensemble. Après avoir proposé une brève historique du management au regard des travaux critiques consacrés au management, nous expliciterons en quoi la démarche ergologique permet de fonder une nouvelle approche du management. Puis, nous verrons en quoi cette nouvelle approche consistant à « faire avec » apporterait des éléments de réponse en termes de santé au travail pour les salariés ainsi que pour les managers eux-mêmes, nous proposerons un renouvellement de fonction des managers qui doivent passer du faire faire, à l’ambition de « faire avec ».
Des démarches capacitantes pour développer les compétences des managers
Authors: Nivet Brigitte , Petit Johann , Falzon Pierre
Published: June 2023

Les formations au management sont peu fondées sur une analyse de l’activité des managers et sur les conditions réelles d’exercice de leur activité. Ce texte s’appuie sur trois cas de formation ou d’intervention visant à transformer l’activité des managers. Le traitement de situations réelles, complexes, sert de support à un travail réflexif permettant de mettre à distance ce qui se passe ou s’est passé, de le prendre comme objet d’analyse et d’en tirer un savoir-faire réutilisable. L’analyse de ces trois cas souligne d’une part le rôle crucial du collectif et de l’interactionnel dans ces processus réflexifs, d’autre part le rôle mixte de l’intervenant-formateur : aide à la résolution des difficultés et soutien au travail réflexif.
Machine Learning-Based Approaches in the Detection of Depression
Authors: Ghosh Dipanwita , Sing Mihir , Adhikary Arpan
Published: June 2023

In the last few decades, psychological health issues, i.e., anxiety, stress, and depression, have become common problems worldwide. Most of those with these issues feel down, sad, and tragic from time to time. Some people experience this problem very strongly for a long period of time without any evident reason. Generally, depression is not a low mood—it is the condition that affects the physical and mental health of a person. Some work has been done by researchers in the detection of depression using machine learning (ML) classifiers. In this chapter, a detailed survey and review of the different works in this area has been carried out. The authors also identified certain drawbacks of these works. Based on which, the authors tried to explore the future scope of works, which will enhance the performance of the existing models in the detection of depression.
Cognitive Cardiac Rehabilitation Using IoT and AI Tools
Authors: Mazumdar Kaushik , Das Sima
Published: June 2023

Cognitive cardiac rehabilitation using IoT and AI tools is a promising approach for improving the effectiveness and efficiency of cardiac rehabilitation programs. The use of IoT devices allows for the remote monitoring of patients' vital signs and physical activity, while AI tools can analyze this data to provide personalized feedback and support. This approach has the potential to enhance patient engagement and adherence to rehabilitation protocols, leading to better outcomes for patients. While the benefits of cognitive cardiac rehabilitation using IoT and AI tools are clear, there are also some challenges that need to be addressed.
Recent Advances in Cyber Security Laws and Practices in India
Authors: Malik Neyha , Husain Firoz , Ali Anis , Elahi Yasir Arafat
Published: June 2023

The growth of the internet and proliferation of applications, products, and services has given rise to cyber threats which require far more stringent security measures than ever before. Some common types of cybercrimes are job fraud, phishing, baiting, vishing, smishing, credit and debit card fraud, child pornography, cyberbullying, etc. Cyber laws need constant upgrading and refinement to keep pace with the increasing technology. In India, various statutes and initiatives have been launched to ensure its cyber security such as Information Technology Act, 2000 (IT Act), Indian Penal Code, 1860 (IPC), National Cybersecurity Framework (NCFS), financial assistance, Cyber Crime Prevention against Women & Children (CCPWC), Indian Cyber Crime Coordination Centre (I4C), National Cyber Crime Reporting Portal, Citizen Financial Cyber Fraud Reporting and Management System, Indian Computer Emergency Response Team (CERT-In), and Ministry of Electronics & Information Technology (MeitY).
Deep Learning-Based Agriculture Monitoring and Forecasting
Authors: Mehta Ishaan , Bharti Santosh Kumar , Mehta Honey , Gupta Rajeev Kumar
Published: June 2023

Smart agriculture has become crucial in meeting the increasing dietary needs of a growing population, particularly in countries where agriculture has significant economic impact. Deep learning techniques, such as convolutional neural networks and recurrent neural networks, have been extensively researched and applied in agriculture in recent years. In this study, recent research articles on deep learning in agriculture over the past five years are analyzed to identify key contributions and challenges. The study has also explored agriculture parameters monitored by the internet of things and used them to train the deep learning algorithms for analysis. The study compares various factors across different studies, including the agriculture area of focus, dataset used, deep learning model and framework, data preprocessing and augmentation methods, and accuracy of results.
Deep Learning-Based Air Pollution Forecasting System Using Multivariate LSTM
Authors: Lavanya K. , Prathik Narayan R.
Published: June 2023

Air quality forecasting is an important way to safeguard public health since it provides ample notice of harmful air pollutants in a given location. Exhaust emissions from gas-guzzling vehicles, industrial pollution, and wildfires obfuscate some of the country's most dramatic vistas and can pose a significant hazard. If forecasts are trustworthy and accurate enough, they can be a crucial component of an air quality control system that complements more conventional emissions-based strategies. This study uses multivariate LSTM Time series forecasting techniques to understand and apply multiple variables together to contribute more accuracy to forecasting due to its proven track record of success with time-series data. The factors that are found to have a major effect on the air quality are dew point, wind speed, temperature, snowfall and rain conditions. In particular, this model focuses on predicting and forecasting the concentrations of PM2.5 (Atmospheric Particulate Matter with a diameter of less than 2.5mm) as this pollutant has a major effect on human health worldwide.
Conversion of Cellulosic Raw Feed Stock Into Cellulose Nanocrystals (CNC)
Authors: Kulkarni Sunil Jayant
Published: June 2023

Over the period, cellulosic biomass and wood were used as a source of energy, clothing, construction material. Cellulose can be modified into microcrystalline and nanocrystalline form for better mechanical and antimicrobial properties. Wood contains 40 to 60% cellulose whereas cotton, 90%. In nanotechnology, the material is disintegrated to have at least one dimension in nanoscale (1 to 100 nanometre). Nanosized particles have unique properties. Nanocellulose can be isolated from cellulosic materials that are abundantly available in nature. Cellulose nanocrystals can be obtained by alkaline treatment, bleaching, hydrolysis, and dewatering route. The crystallinity index of derived CNC varies from 52 to 99%. Sugarcane peel fiber was reported to have a maximum of 99.2% crystallinity. Combination of CNC with other materials, this can yield better and desired properties. Water sensibility and permeability can be minimized for their application in films by adding citric acid in the structure.
Using Social Media Data for Exploring Healthcare Service Quality
Authors: Halaweh Mohanad , Salameh Fathi Fayeq
Published: June 2023

The provision of quality services in the healthcare sector has become a highly prioritized goal, as it is seen as a key factor in the satisfaction and loyalty of patients. This study aims to explore patients' perception of service quality in the UAE, a topic that has not yet been extensively studied. A qualitative approach, using social media data, was employed. Grounded theory techniques were used to analyze online feedback and comments on clinical services posted by patients. Results revealed five key factors that shape patients' perception of service quality: time efficiency, human interaction, complementary facilities, value for money match, and accountability. This study's findings and implications, particularly regarding how technology can be used to guarantee quality services and address issues raised in the research, are discussed.
Analysis Method of App Software User Experience Based on Multisource Information Fusion
Authors: Chen Yongquan , Jiang Ying , Liu Haiyi
Published: June 2023

With the rapid development and popularization of intelligent terminals, app software has also developed rapidly. The research and practical value of mining user experience (UX) of app software form interaction information are becoming increasingly prominent. The interactive information of app software is multisource homogeneous and heterogeneous. In order to obtain more accurate and more comprehensive app software UX results, the fused multisource information should be analyzed. In this paper, the app software UX analysis method based on multisource information fusion is proposed. First, feature engineering is carried out to extract the features. Then, the feature combination tree is constructed after feature correlation mining. Finally, the multisource app software interactive data are fused, and the result is further analyzed to obtain the information of app software UX. The experiments clearly show that the method can effectively fuse multisource app software interaction data and help to comprehensively mine the app software UX embodied in the data.
A Review on Oversampling Techniques for Solving the Data Imbalance Problem in Classification
Authors: Piyadasa Tharinda Dilshan , Gunawardana Kasun
Published: June 2023

The data imbalance problem is a widely explored area in the Machine Learning domain. With the rapid advancement of computing infrastructure and the incessant increase in the amount and variety of data generated, the data imbalance problem has prevailed and reshaped with the requirement for novel approaches to address it. Among the different approaches that exist to address the data imbalance problem, such as data-level and algorithmic-level, data-level approaches are more popular among the scientific community due to their classifier-independent nature. When investigating current trends in data-level approaches, it is evident that oversampling is a technique frequently explored due to its adaptability to scenarios where extreme data imbalance is present. This paper presents a review of different oversampling techniques with a comprehensive analysis of the strategies that have been used along with possible areas that looks promising to explore further to develop more advanced oversampling techniques.
Pharmacoeconomics amidst a financial crisis
Authors: Williams S. S. , Medagedara A. U. , De Silva H. A.
Published: June 2023

Cost effective strategies must be implemented amidst an economic crisis in Sri Lanka to mitigate ever increasing medicinal costs. Exploration of measures such as evidence based generic prescribing, cost effectiveness analysis, value-based pricing, identification of low cost, high value medication and being sensitive to the ability of the patient to purchase medicine is a necessity. Clinicians must be sensitised to this issue to contribute actively to the process. Policies in line with pharmacoeconomic realities must be pursued.
Evaluation of an Automatic System for Cockpit Integration Testing
Authors:   TXT e-Tech, Frisini David ,   Leonardo Helicopter Division, Taumaturgo Vomcemzp , Giulianini Glorgia , Romano Marco , Zonzini Nicola , Rinaldi Glauco
Published: June 2023

The purpose of this paper is to report the results of the evaluation conducted on ARTO, an automated system designed to perform integration tests that require interaction with the cockpit. The system has two key elements, the robotic manipulator that acts on the cockpit panels and displays, and the Computer Vision that collects the visual information. The methodology followed during the activity addressed different technical processes of system engineering, starting from the architectural design of the system up to the validation in a representative testing environment. For the validation environment of ARTO, TXT E-Tech, and Leonardo Helicopters have chosen the LHD Next-Gen Civil Tiltrotor-Technology Demonstrator (NGCTR-TD) Avionics Full Scale Integration Rig (FSIR). The results collected during this activity comprehend several KPIs chosen because significant in terms of accuracy and test operation efficiency.
An Assessment of FVL Readiness of Certifiable MOSA Ethernet Digital Backbone Solutions
Authors:   TTTech North America, Finnegan Daniel , Soares Alvaro , Zischka Wolfram
Published: June 2023

Modern aircraft employ an ever-growing array of sensors, probes, displays, and other high-integrity avionics. This has grown to the point where legacy networking technologies like MIL-STD-1553 and ARINC-429 are no longer sufficient. At the same time, a growing emphasis on Modular Open Standards Approach (MOSA) in defense acquisitions has moved toward favoring more open standards. This presents an opportunity to leverage ubiquitous, high-bandwidth, and flexible Ethernet into an avionics context. The US Army Future Vertical Lift (FVL) initiative presents a key opportunity to realize the advantages of Ethernet for avionics networking by using it as the basis for an avionics Digital Backbone. This paper will evaluate the Certification Readiness, Maturity, and MOSA-Conformance of the Ethernet technologies likely to be featured on FVL aircraft: IEEE 802.3 Best-Effort (BE) Ethernet, Time-Triggered Ethernet (TTE), and IEEE 802.1 Time Sensitive Networking (TSN). All the listed technologies are open Ethernet standards, allowing the system architect to deploy them as needed based on the specific use case and program requirements. This evaluation assesses these three Ethernet technologies on aspects necessary to safely manage flight-critical data over a real-time network, including native fault tolerance, determinism, software dependency, and certifiability. The paper also assesses the technological maturity of each technology in relation to the planned timeline for FVL and evaluates how evolution of the technologies could impact MOSA-conformance. This paper will ultimately recommend a mixed network of a Time-Triggered Ethernet Digital Backbone for high-criticality Air Vehicle System traffic with Best-Effort Ethernet or Time-Sensitive Networking for lower-criticality Mission System traffic.
Helicopter In-Flight Eye Tracking: System Integration Aspects and First Results
Authors:   German Aerospace Center - DLR, Maibach Malte-Jörn , Greiwe Daniel , Müllhäuser Mario
Published: June 2023

In modern helicopters highly accurate flight state data is available through precise sensors and complex fusion algorithms in the aircraft. This data is used by the avionic systems and transported to the pilot through sophisticated human machine interfaces (HMI). Especially in helicopters, the pilot is in most flight phases directly involved in the control of the aircraft and uses the information provided by the HMI. However, in most civil aircraft no sensor systems exist to get an insight about the pilots physiological state. Even in experimental helicopters there is no real-time information about the pilots mental state and this information is typically gathered through questionnaires in the debriefing. One way to close this gap is to use physiological measurement systems such as eye tracking. In our work we integrated an eye tracking system into the experimental system of DLR's research simulator AVES and the research helicopter ACT/FHS. In this paper we describe the first steps, which include the selection of the systems, technical aspects of the hardware and software integration process and first experiments in DLR's Bo 105 helicopter and DLR's AVES simulator. Details of our developed toolchain for the live data conditioning are given and first results of combined helicopter state and eye tracking data are presented. In the end we give an outlook on the next integration steps, which include the combination with a high-fidelity head tracking system.
Quantifying Taskload and Workload with Instantaneous Power Spectrum: An Initial Assessment of 3D Conformal Cueing in Rotorcraft Shipboard Landings
Authors:   Georgia Institute of Technology, Zander Kevin , Alstrom Robert , Tauro-Padival Rahul , Prasad J.V.R. , Feigh Karen
Published: June 2023

The authors present a novel taskload metric, Instantaneous Power Spectrum (IPS), and use the IPS to investigate the taskload of pilots conducting helicopter shipboard operations with and without cueing sets. A brief review of the most relevant studies on the application of time-frequency analysis to flight dynamics is provided to situate the reader. The authors derive the IPS from classical time-frequency analysis methods and modify it using foundational rotorcraft inceptor theory. The accuracy of IPS as a taskload metric is assessed by analyzing a small set of helicopter shipboard landing scenarios with and without the assistance of 3D Conformal Pilot Cueing. The goal of the study is to explore the relationship of power in crossover (0.5-1.0 Hz) and stabilization (1.0-2.5 Hz) frequency bands to the taskload experienced by the pilot. These initial results indicate that the IPS is comparable to the well-established time-varying power frequency and provides detailed insight into pilot taskload during maneuvers.
Validated Technologies to Maintain Spatial Orientation
Authors:   Engineering Acoustics Inc., Mortimer Bruce ,   Embry Riddle Aeronautic University, French Jon , McGrath Braden , Rupert Angus
Published: June 2023

Maintenance of spatial orientation (SO) is critical for safe military and civilian flight. This work describes the validation of a vibrotactile array that is used to provide continuous orientation information to pilots during flight. Continuous tactile orientation information has the potential to improve the maintenance of SO under conditions of pilot distraction and/or during degraded visual environments. This work summarizes a series of experiments where participants reported their perceived orientation during test flight maneuvers, while under various controlled, sensory reference conditions. During maneuvers where visual, tactile cueing, or information from both combined, all participants maintained spatial orientation. The test flight data were then used to extend a human gravito-inertial orientation biomathematical model that is capable of predicting pilot perceptions resulting from the integration of orientation/motion cues provided by visual, auditory, vestibular, and somatosensory senses.
Individual Blade Pitch Control (IBC) for Vibration Reduction of Lift-Offset Coaxial Rotor Vehicles with Auxiliary Propulsion
Authors:   The Pennsylvania State University, Beyer Jessica , Smith Edward , Schmitz Sven , Zhang Jianhua
Published: June 2023

The present study investigates the vibration reduction potential of single harmonic individual blade pitch control (IBC) applied to a lift-offset coaxial main rotor. An open-loop phase sweep is conducted using comprehensive aeroelastic simulations of the XH-59A rotor to quantify the effects of IBC on the hub vibration index and the rotor effective lift-to-drag ratio. Applying 4/rev, 1 degree amplitude IBC at 0 degree phase to both rotors decreased the hub vibration index by 64% at 200 knots and only decreased the rotor lift-to-drag ratio by 2%. Single harmonic IBC retained effective hub vibration index reduction with varying flight speed, including a 56% decrease at 160 knots and a 69% decrease at 240 knots. Higher amplitude IBC inputs were more effective at higher forward flight speeds. The vibration reduction of single harmonic IBC with 2 degree pitch amplitude increased from 24% to 69% when the forward flight speed increased from 160 to 240 knots. Application of a closed-loop control algorithm using multiple-harmonic IBC achieved an 84% decrease in the hub vibration index with only a 2% decrease in the rotor effective lift-to-drag ratio.
S-97 RAIDER® Propulsor Flight Loads and Validation
Authors:   Sikorsky a Lockheed Martin Company, Schuster Daniel
Published: June 2023

The S-97 RAIDER® helicopter uses a pusher propeller to provide forward and reverse thrust capability to Sikorsky's X2 Technology™ design. Due to the propeller's aft mounting location on the aircraft it experiences aerodynamic interactions with both the airframe wake and main rotor wake across the flight envelope. This paper details the inclusion of an aerodynamic interference flow field near the propulsor disk plane in a CSD (Computational Structural Dynamics) propulsor model used to predict blade loads. The interference flow field uses either wind tunnel measurement or CFD (Computational Fluid Dynamics) to define the aerodynamic flow near the propeller plane. The predicted blade loads were compared with flight test data at a variety of steady flight conditions and overall good agreement is found between simulation and test. The simulation methodology is also expanded to simulate transient hover and acceleration conditions using a quasi-steady trim approach at multiple discrete time points of the maneuver. Overall good correlation of the measured blade maximum, minimum, and vibratory loads are achieved.
Analysis of Flap-Lag Aeroelastic Stability at High Advance Ratios
Authors:   University of Maryland, Fishman Spencer , Chopra Inderjit
Published: June 2023

The aeroelastic stability of rotor blades in the flap and lag degrees of freedom is analyzed in preparation for high advance ratio wind tunnel testing of Mach-scaled rotors. A wide range of advance ratios (0 ≤ μ ≤ 3) and Lock numbers (0 ≤ g ≤ 18) are evaluated for articulated and hingeless rotor configurations. Linearized equations of motion are derived in the rotating frame. Periodic coefficients, reverse flow, pitch coupling, and collective inputs are considered. Floquet Theory is used to evaluate the stability of the equations of motion in response to perturbations from the trimmed state. Results are compared to past analyses and expanded to higher advance ratios. Damping and frequency response behavior are evaluated, and rotor stability boundaries are presented.
Development of a Datadriven Model for Prediction of Vibrational Discomfort in Helicopters
Authors:   University of Stuttgart, Burkhardt Tim , Özkurt Süleyman , Schimpf Fabian , Fichter Walter
Published: June 2023

Ensuring passenger comfort is an essential task of manned aviation. To describe the discomfort as a result of the entire vibration environment of a helicopter, an evaluation procedure is required. Currently, the most comprehensive approach to evaluate discomfort caused by whole-body vibration is described in ISO2631-1. Since ISO2631-1 is based on uniaxial and sinusoidal laboratory experiments, the discomfort evaluation of complex helicopter vibrations is not correctly reflected. This paper describes the systematic creation of an evaluation procedure for discomfort caused by whole-body vibration. Based on a study in a realistic helicopter environment, a data-driven evaluation procedure is derived that can also be applied to other experimental campaigns. Two possibilities for the structure of the evaluation procedure are presented. One is derived by optimizing the metric to the measured data. Therefore, a larger computation time is required. With the other structure, the calculation time is reduced by some simplifications. The calculation procedure is similar to that of ISO2631-1. The procedure determined in this way can be used, among other things, for future flight controller design. The newly developed model provides more accurate predictions of discomfort than the previous standard for helicopter applications.
Aeroelastic Design of a High Speed Highly Efficient Rotor
Authors:   Sikorsky A Lockheed Martin Company, Sutton Chris , Matalanis Claude , Modarres Ramin , Min Byung-Young , Klimchenko Vera , Wake Brian
Published: June 2023

The aeroelastic design of a high speed highly efficient rotor, from conceptual layout to detailed design, is presented. The overall strategy is described along with details and a demonstration case on the conceptual design optimization strategy. In Phase I, rapid design iterations were performed using lower order quick turnaround tools to establish basic design aspects such as rotor head sizing and stiffnesses. In Phase II, higher order tools are implemented along with a more realistic structural representation of the head and blades. The outcome is a robust preliminary design to be analyzed with CFD-CSD and tuned further in detailed design without requiring major rework. Finally, dynamic tailoring performed on the blade during final design is presented. This was done to maintain or improve frequency placements and vibration levels as relatively small, surgical changes were made to the blade detailed design (ply thicknesses, orientations, blade weights, etc.) to satisfy strength, life, and manufacturability requirements. This work highlights the importance of upfront aeromechanics optimization to establish a robust early conceptual design, and high-fidelity analysis through final design to maintain desired characteristics.
Experimental Testing of Advanced Generalized Predictive Control for Stability Augmentation and Vibration Reduction of Tiltrotor Aircraft
Authors:   NASA, Ivanco Thomas ,   US Army Research Laboratory, Kreshock Andrew ,   Old Dominion University, Newman Brett , Thornburgh Robert , Wilbur Matthew
Published: June 2023

Generalized Predictive Control (GPC) is an advanced form of an adaptive control algorithm that uses experimentally acquired data to determine the input-output relationship of complex systems through a process called system identification (system ID). GPC has historically been applied to wind tunnel tests of dynamically-scaled tiltrotor aircraft for stability augmentation and vibration reduction since the complex nature of these dynamic systems does not lend itself well to traditional control theory. Advanced GPC (AGPC) improves upon traditional GPC by enabling self-adaptation as conditions change from those used to acquire the system ID and controller performance would normally erode. The present research expands upon previous analytical development and demonstration of AGPC with experimental demonstration. To support AGPC, this present work also identifies and describes figures of merit that define a good working controller and quantifies the uniqueness of the control inputs and quality of the system ID parameters. The present research demonstrates that AGPC consistently performs better than traditional GPC and can successfully adapt to changing conditions.
Rotor Cross-Tilt Optimization of Manned Multi-rotor eVTOL Aircraft for Yaw Control Efficiency
Authors:   Zhejiang University, Yan Xufei , Cai Jiandong , Lou Bin , Hu Yiren , Xie Anhuan , Zhu Shiqiang , Cheng Libo , Wang Xiaobo
Published: June 2023

This paper proposed a rotor cross-tilt optimization method of manned multi-rotor eVTOL aircraft for yaw control efficiency improvement. Firstly, the flight dynamics model of a 500kg low-altitude manned multi-rotor eVTOL aircraft is established, and the accuracy of the model is verified by single arm test platform and flight test data. Then, a rotor cross-tilt optimization method which simultaneously completes the trim and optimization calculation, is designed to maximize the overall control efficiency under different loads, forward flight speeds and rotor mounting angle errors. The manipulation derivative is applied to analyze the influence of the optimal rotor tilt angle on the control efficiency of each control channel. Finally, the feasibility of the optimization method is verified by comparing the ground(3DOF test platform) and flight test data of the prototype before and after optimization. Results show that the control efficiency of yaw channel is improved while the control efficiency of other control channels are basically maintained, so as to achieve the overall optimal control performance. In addition, the endurance time of the prototype is also improved, and the greater the load, the more obvious the improvement.
Comprehensive Simulation with Coupled Airframe-Propulsion Dynamics in Support of eVTOL Design
Authors:   Gamma Technologies GmbH, Brenner Felix ,   Advanced Rotorcraft Technology, Goericke Jan , Hasbun Matt
Published: June 2023

A major consideration in the design and development of rotorcraft vehicles to support Urban Air Mobility (UAM) is meeting their mission endurance requirements. This is especially true of Electric Vertical Take-Off and Landing (eVTOL) configurations, with modern batteries providing significantly less energy storage density compared to traditional fossil fuel or hybrid-electric power sources. This constraint on available energy requires careful design of the entire propulsion system, from batteries to rotors, to maximize efficiency. Additionally, integrated full vehicle and propulsion system simulation and optimization of mission power requirements may be used early in the design to mitigate the risks associated with limited energy storage. This optimization can reduce the total weight of the components of the electric propulsion system including the sizing of the appropriate heat dissipation components. This study explores the coupling of a comprehensive flight dynamics model with a physics-based electric propulsion system in support of conceptual and preliminary aircraft design. The coupled simulation models are exposed wind profiles during the eVTOL hover stationkeeping to investigate the transient effects on aircraft response, effectiveness of the electric propulsion system, battery discharge, and heat dissipation.
Experimental and Computational Investigation of a Stacked RotorWith Unequal Radii
Authors:   University of Texas at Austin, Johnson Chloe ,   DEVCOM ARL, Jacobellis George , Sedlacek Vasha , Sirohi Jayant
Published: June 2023

The loads and acoustics of a coaxial, co-rotating, or stacked, rotor with unequal upper and lower rotor radii were explored through measurements and simulations. The upper and lower rotor radii were both set to the nominal radius of 1.108 m, as well as the upper rotor radius to 90% nominal radius and the lower rotor radius to 90% nominal radius, with an axial spacing of 5.27% nominal radius. Simulations of the rotor system were made using the Rotorcraft Comprehensive Analysis System (RCAS) viscous vortex particle method and acoustic predictions were made coupling RCAS with the PSU-WOPWOP and ANOPP2. The simulations were validated with the NASA ideal twist rotor. The most accurate simulations of the stacked rotor were observed using PSU-WOPWOP's tonal noise predictions and the Brooks, Pope, and Marcolini method implemented in ANOPP2 with a maximum sectional Reynolds number to apply untripped conditions. Flow visualization and blade tip vortex tracking revealed that vortex interactions on the upper surface of the lower rotor blade resulted in adverse broadband noise generation. Therefore, the radius of one rotor was decreased to avoid tip vortex interactions, and subsequent measurements and simulations were made at constant thrust conditions of 150 lbf. Total rotor noise was reduced by 4.5 dB with minimal power increases by shortening the lower rotor to 90% nominal radius. This noise reduction was not captured by the simulations, as the vortex interaction with the rotor blade's boundary layer is not incorporated in current broadband models.
In-flight Measurements and Validation of Electric Powertrain Models
Authors:   Texas A&M University, Saemi Farid ,   Army Research Laboratory, Mitsingas Constandinos , Dunston Owen , Benedict Moble
Published: June 2023

Small electric drones are popular vehicles for consumers and researchers. However, literature contains little data on in-flight aerodynamic loads that could validate aerodynamic or electric powertrain design tools. We developed a specially instrumented quadcopter to directly measure and record rotor torque and rotational speed during flight. We used this data to validate powertrain efficiency models for the motor, motor controller, and battery. The validated models predicted the time histories for battery discharge, controller current, and combined motor+controller efficiency within 5%, 20%, and 25% of experimental flight data respectively. The validated models can help engineers explore drone concepts without costly experiments and reduce program development costs. The novel flight data can help researchers validate other models, such as vehicle aerodynamic performance models. The modular instrumentation can help engineers measure analog signals onboard a flying vehicle for other applications, such as the wing loading on a fixed-wing drone.
Towards Flight Envelope Protection for the NASA Tiltwing eVTOL Flight Mode Transition using Hamilton-Jacobi Reachability
Authors:   Bechamo LLC, Hsu Ting-Wei ,   UC Berkley, Choi Jason ,   NASA Armstrong Flight Research Center, McWherter Shaun , Amin Divyang , Piedmonte Michael , Tomlin Claire
Published: June 2023

This paper presents a collaborative research effort between authors from Bechamo LLC, UC Berkeley, and NASA to establish a framework for applying Hamilton-Jacobi Reachability Analysis to the full 6-DOF dynamics of the NASA Tiltwing vehicle, verifying the safe flight envelope during the flight mode transition between hover and cruise flight, which prevents loss of control of the vehicle and ensures recoverability to safe trim conditions. This involved first verifying the nominal flight mode transition path as a series of trim points, defining the safe flight envelope using reachability, and decomposing the system dynamics into longitudinal and lateral subsystems. Our formulation guarantees the computed envelope's robustness against modeling errors and uncertainty, and the usage of state decomposition significantly improved the tractability of the reachability computation. The framework's success is validated through 6-DOF Monte Carlo nonlinear simulation of vehicle dynamics, demonstrating that the vehicle states within the flight envelope can successfully recover to trim states and continue a safe flight mode transition.
Active Reduction of Unsteady Rotor Noise via Redundant Control Allocation
Authors:   University of Maryland, Bugday Batin , Saetti Umberto
Published: June 2023

This paper demonstrates the development and implementation of active noise abatement flight control laws that make use of redundant control allocation. A periodic equilibrium of the coupled rotorcraft flight dynamics and acoustics is first found at a desired flight condition using a modified harmonic balance trim solution method. Next, the nonlinear time-periodic dynamics are linearized about that periodic equilibrium and transformed into an equivalent higher-order linear time-invariant system in harmonic decomposition form. Composite aeroacoustic measures are included as an output of this system. To speed up runtime and make control design tractable, the order of these harmonic decomposition models is reduced via residualization to an 8-state model where the states are representative of the rigid-body dynamics of the aircraft. This 8-state model is shown to provide accurate acoustic response predictions for small-amplitude pilot inputs and to abate runtime by a factor of approximately 10⁵, thus enabling acoustic predictions in generalized maneuvering flight that are significantly faster than real-time. The 8-state model is subsequently used to synthesize an Explicit Model Following (EMF) control law with pseudo-inverse allocation to redundant control surfaces. In this study, the redundant control surfaces taken into consideration were an active horizontal stabilizer (or stabilator). Results demonstrate that while affinity in the controls yields little potential for noise abatement, the use of redundant control surfaces is an effective method for active reduction of unsteady rotor noise. In fact, redundant control allocation was shown to be increasingly effective with increasing aggressiveness in maneuvers. Within the context of future-generation rotorcraft, noise abatement through redundant control allocation will be particularly effective for Future Vertical Lift (FVL) configurations featuring high levels of control redundancy and capable of aggressive maneuvering flight.
The Impact of Control Augmentation and Stability Augmentation System Parameters on Kinetosis of Rotorcraft Passengers
Authors:   University of Stuttgart, Ozkurt Suleyman , Burkhardt Tim , Schimpf Fabian , Fichter Walter
Published: June 2023

Kinetosis is provoked by low-frequency vibrations below 0.5 Hz. The severity of kinetosis increases with increased vibrational magnitudes within the mentioned frequency range. In rotorcraft, these frequency range intersects with the bandwidth of automatic flight control systems. The counterreactions of the automatic flight control system to atmospheric disturbances lead to vibrations within its bandwidth. The magnitude of these vibrations depends on the disturbance rejection properties of the implemented flight control system. Consequently, it is assumed that the severity of kinetosis depends on the design parameters of the flight control system. To confirm this assumption, a controller to stabilize the helicopter and track commanded attitude angles is proposed. The parameters of the controller are permutated to analyze their impact on kinetosis under turbulent atmospheric conditions. Further, a mathematical kinetosis model is adapted to experimental results obtained from helicopter vibrations. This modified model is used to evaluate the accelerations and angular velocities of the closed-loop helicopter regarding kinetosis. The results of this work show that the disturbance rejection properties, hence the control parameters, affect the vibration magnitudes. Therefore, the extent of kinetosis is driven by the control parameters of the stabilization and control augmentation system.
Flying Qualities Analysis and Piloted Simulation Testing of a Lift+Cruise Vehicle with Propulsion Failures in Hover and Low-Speed Conditions
Authors:   NASA Langley Research Center, Altamirano George ,   NASA Armstrong  Flight Research Center, Suh Peter ,   NASA Ames Research Center, Malpica Carlos , Matt Justin , Foster John , Hunson Curtis , Schuet Stefan
Published: June 2023

The recent emergence of electric-Vertical Take-Off and Landing (eVTOL) vehicles for Urban Air Mobility (UAM) applications has resulted in a wide variety of configurations with unique stability and control characteristics. NASA is currently conducting research to develop conceptual design tools to accelerate public acceptance of these vehicles which includes requirements for safety during failure scenarios. This paper summarizes progress toward a toolbox for predicting flying qualities of eVTOL vehicles during critical propulsion failures that could impact the allowable design of the vehicle geometry or control system. Key topics include unique vulnerabilities of eVTOL/multirotor vehicles to propulsion failures, relevant flying qualities design metrics, and simulation modeling requirements for assessing flying qualities degradation due to failures. Results of a piloted simulation study conducted in the NASA Ames Vertical Motion Simulator (VMS) are presented. The VMS experiment was designed to assess and validate key handling qualities and safety design metrics for propulsion failures. These results show the correlation between control system design requirements and the degradation in handling qualities for various propulsion failures.
Modeling of Helicopter Pilot Behavior through Methods of Artificial Intelligence
Authors:   University of Stuttgart, Heni Najrane , Rothaupt Benjamin , Fichter Walter
Published: June 2023

Machine Learning algorithms are used in this paper to synthesize models for an ultralight coaxial helicopter pilot controlling the roll- and pitch motion during stationary hover. Different topologies of neural networks modeling the pilot are evolved with a neuroevolutionary algorithm, and trained via a data-driven approach using datasets that are collected from both real hover sequences and piloted flight simulations. The models are validated using flight test data and evaluated in a closed loop simulation alongside helicopter and turbulence models. Results demonstrate the models capability to stabilize the helicopter during hover and thus, to imitate human pilot behavior.
Urotensin II promotes the proliferation and secretion of vascular endothelial growth factor in rat dermal papilla cells by activating the Wnt-β-catenin signaling pathway
Authors: Liao Congjuan , Huang Zhen , Chen Liuting , Fan Xiaorong , Peng Jun , Tan Xiaoqing , Yang Jianshe , Zhang Xusheng
Published: June 2023

Introduction. Urotensin II (U II) is a kind of active peptide with a variety of biological effects, such as promoting cell proliferation and endocrine effects. The aim of this study is to investigate the effect of urotensin II on the proliferation and secretion of vascular endothelial growth factor (VEGF) in cultured rat dermal papilla cells (DPCs), and to explore its molecular mechanism. Materials and Methods. We used the DPCs isolated from the thoracic aortas of Wistar-Kyoto rats to run the CCK8 and ELISA assay, RC-PCR and Western blotting techniques to identify the effect of Urotensin II on the proliferation and secretion of VEGF in DPCs, data were analyzed by one-way ANOVA or t-test. Results. U II can increase the mRNA expression of proliferation markers Ki67 and PCNA. In addition, the Wnt/β-catenin pathway was activated by U II, but Wnt inhibitor DKK1 reversed the effect of U II. Conclusions. U II promoted the proliferation and secretion of VEGF in rat DPCs through activation of the Wnt-β-catenin signaling pathway.
Morphometry of Skulls from North Indian Population
Authors: Khan Abeer Zubair , Srivastava Stuti , Qadeer Fardan , Srivastava Geetanjali , Paiker Mah , Haque Mahboobul
Published: June 2023

Introduction:

Anthropometric studies have shown significant variations in the cranium and orbits between races and genders due to various factors such as genetics, race, hormones, nutritional differences, and environmental influences. The present study aims to record cranial and orbital dimensions and indices to classify skulls based on these measurements.

Materials and Methods:

Thirty-five human adult skulls were obtained from the dissecting laboratory and museum of Hind Institute of Medical Sciences, Safedabad. The orbital height, width, interorbital distance, maximum length, and width of the cranium were measured directly using a digital Vernier caliper. The skulls were then classified based on the orbital and cranial indices calculated.

Results:

The study found a mean orbital index of 83.42, classifying the skulls as mesoseme, and a cranial index of 73.15, classifying them as dolichocephalic.

Conclusion:

Basic data and records of morphometry of bones belonging to specific regions can help identify the ethnicity and race of a person. Understanding the correlation of dimensions of the orbital cavity and cranium is crucial in certain conditions, such as interpreting fossils, classification of skulls in forensic medicine, and discovering trends in evolution and racial differences. These findings may also aid in identifying unclaimed bodies in India, which are found in significant numbers yearly.
Bilinear Numerical Analysis of the Structural Behavior of a Dental Implant Applied as a Biomaterial Carbon Fiber Reinforced Polyether-Ether-Ketone (CFR-PEEK)
Authors: Martinez-Mondragon Miguel , Urriolagoitia-Sosa Guillermo , Romero-Ángeles Beatriz , Pérez-Partida Juan C. , Cruz-Olivares Itzel M. , Urriolagoitia-Calderón Guillermo
Published: June 2023

Introduction:

This research aims to compare the distribution of stresses and general displacements between different dental implant abutments against a healthy tooth, as well as the mechanical behavior of the carbon fiber-reinforced polyether-ether-ketone (CFR-PEEK) material under load conditions.

Methods:

A biomodel of a healthy tooth was implemented by computed tomography (CT), considering three essential parts of the tooth (enamel, dentin, and pulp). Three different dental abutments were produced using the SolidWorks computer program. Applying the finite element method (FEM), a numerical evaluation was performed by introducing a critical load of 550 N and then unloading it to 0 N taking into consideration the behavior of the material (titanium and CFR-PEEK) as bilinear, isotropic, and homogeneous.

Results:

The difference in stress and total displacement between the dental implant (titanium and CFR-PEEK) and the healthy tooth was significant, going from critical stress values of 1087 to 324 MPa.

Conclusion:

When removing the load from the CFR-PEEK material, it presented residual stresses because the material passed its elastic limit despite this, demonstrating a better mechanical behavior than titanium.
Serum and Salivary Vitamin B12 Levels among Iron Deficiency Anemia Patient with Recurrent Aphthous Stomatitis
Authors: Al-hamdani Ghaith Majid , Yas Layla Sabri
Published: June 2023

Introduction:

We aimed to evaluate serum and salivary vitamin B12 levels in patients with iron deficiency anemia (IDA) with and without recurring aphthous ulcers (RAS).

Methods:

Study participants were divided into three groups, clinically healthy control group (n = 25), an IDA patient with RAS (n = 25), and an IDA without RAS (n = 25). The enzyme-linked immunosorbent assay (ELISA) method was used to assess the serum and salivary B-12 levels blindly. Data analyses were performed using one-way ANOVA and the Tukey’s post hoc test using R software.

Result:

There were statistically significant differences regarding serum and salivary B12 levels among study groups (P<0.001). All pairwise comparisons showed significant differences regarding serum (P<0.001) and salivary (P ≤ 0.002) B12 levels.

Conclusion:

The Control group (396 ± 18.2 pg/mL) was within the normal serum level of vitamin B12 (200-900 pg/mL), while in IDA with RAS (111 ± 15.4 pg/mL) and IDA without RAS (145 ± 57.2 pg/mL) serum level of vitamin B12 is lower than the normal range and significantly lower than the control group.