The Design and Evaluation of Complex Systems: Application to a Man-Machine Interface for Aerial Navigation

1979 ◽  
Vol 23 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Dennis B. Beringer
Keyword(s):  
Flight Control ◽  
Tracking Error ◽  
Data Entry ◽  
Digital Data ◽  
Training Time ◽  
Subsequent Performance ◽  
Navigation Data ◽  
Wide Range ◽  
Dynamic Map ◽  
Aerial Navigation

Systematic and economic design and evaluation strategies were applied to a computer-generated 4-D aerial navigation system. During the evaluation each of 24 experienced instrument pilots received training in a PLATO-based digital flight simulator using either a keyboard entry/static map, keyboard entry/dynamic map, or touch entry/dynamic map system. Tasks performed during the execution of an area navigation course included continuous flight control, navigation data updating, digital data entry, and amended course plotting. Digital data entry training time was comparable for all three systems but the touch-map proved superior for the plotting tasks, greatly reducing training and task execution times while virtually eliminating errors. Subsequent performance evaluation showed that the touch-map reduced flight path tracking error, increased processing rates on a digit-cancelling secondary task, and increased the accuracy of manual plotting operations. It was concluded that a touch entry system could significantly reduce cockpit workload across a wide range of operational environments.

Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

A comparison of select trigger algorithms for automated global seismic phase and event detection

1998 ◽  
Vol 88 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Mitchell Withers ◽  
Richard Aster ◽  
Christopher Young ◽  
Judy Beiriger ◽  
Mark Harris ◽  
...  
Keyword(s):  
Real Time ◽  
Data Streams ◽  
Event Detection ◽  
Spectral Characteristics ◽  
Digital Data ◽  
Robust Detection ◽  
Location System ◽  
Global Correlation ◽  
Seismic Coda ◽  
Wide Range

Abstract Digital algorithms for robust detection of phase arrivals in the presence of stationary and nonstationary noise have a long history in seismology and have been exploited primarily to reduce the amount of data recorded by data logging systems to manageable levels. In the present era of inexpensive digital storage, however, such algorithms are increasingly being used to flag signal segments in continuously recorded digital data streams for subsequent processing by automatic and/or expert interpretation systems. In the course of our development of an automated, near-real-time, waveform correlation event-detection and location system (WCEDS), we have surveyed the abilities of such algorithms to enhance seismic phase arrivals in teleseismic data streams. Specifically, we have considered envelopes generated by energy transient (STA/LTA), Z-statistic, frequency transient, and polarization algorithms. The WCEDS system requires a set of input data streams that have a smooth, low-amplitude response to background noise and seismic coda and that contain peaks at times corresponding to phase arrivals. The algorithm used to generate these input streams from raw seismograms must perform well under a wide range of source, path, receiver, and noise scenarios. Present computational capabilities allow the application of considerably more robust algorithms than have been historically used in real time. However, highly complex calculations can still be computationally prohibitive for current workstations when the number of data streams become large. While no algorithm was clearly optimal under all source, receiver, path, and noise conditions tested, an STA/LTA algorithm incorporating adaptive window lengths controlled by nonstationary seismogram spectral characteristics was found to provide an output that best met the requirements of a global correlation-based event-detection and location system.

scholarly journals A preliminary survey of the broadband seismic wavefield at Puu Oo, the active vent of Kilauea volcano, Hawaii

1996 ◽  
Vol 39 (2) ◽  
Author(s):  
D. Seidl ◽  
M. Hellweg ◽  
P. Okubo ◽  
H. Rademacher
Keyword(s):  
Frequency Band ◽  
Power Spectra ◽  
Volcanic Tremor ◽  
Digital Data ◽  
Periodic Pattern ◽  
Data Logger ◽  
Remarkable Feature ◽  
Wide Range ◽  
Active Vent ◽  
Seismic Wavefield

The seismic wavefield near an active volcanic vent consists of superimposed signals in a wide range of frequency bands from sources inside and outside the volcano. To characterize the broadband wavefield near Puu Oo, we deployed a profile of three three-component broadband sensors in a 200 m long line about 1.5 km WSW of the active vent. During this period, Puu Oo maintained a constant, but very low level of activity. The digital data logger recorded the wavefield continuously in the frequency band between 0.01 and 40 Hz between June 25 and July 9, 1994. At the same time, local wind conditions along with air temperature and pressure were monitored by a portable digital weather station. On the basis of characteristic elements, such as waveform, spatial coherence between stations, particle motion and power spectra, the wavefield can be divided into three bands. The dominant signals in the frequency band between 0.01 and 0.1 Hz are not coherent among the stations. Their ground velocities correlate with the wind speed. The signals in the 0.1 to 0.5 Hz band are coherent across the profile and most probably represent a superposition of volcanic tremor and microseisms from the Pacific Ocean. Much of the energy above 0.5 Hz can be attributed to activity at the vent. Power spectra from recordings of the transverse components show complex peaks between 0.5 and 3 Hz which vary in amplitude due to site effects and distance. On the other hand, power spectra calculated from the radial components show a clearly periodic pattern of peaks at 1 Hz intervals for some time segments. A further remarkable feature of the power spectra is that they are highly stationary.

scholarly journals Word embedding for French natural language in healthcare: a comparative study (Preprint)

2018 ◽  
Author(s):  
Emeric Dynomant ◽  
Romain Lelong ◽  
Badisse Dahamna ◽  
Clément Massonaud ◽  
Gaétan Kerdelhué ◽  
...  
Keyword(s):  
Discharge Summary ◽  
Word Embedding ◽  
University Hospital ◽  
Graphical Interface ◽  
Training Time ◽  
Formal Evaluation ◽  
Wide Range ◽  
Test Sets ◽  
Human Validation ◽  
Mathematical Operations

BACKGROUND Word embedding technologies are now used in a wide range of applications. However, no formal evaluation and comparison have been made on models produced by the three most famous implementations (Word2Vec, GloVe and FastText). OBJECTIVE The goal of this study is to compare embedding implementations on a corpus of documents produced in a working context, by health professionals. METHODS Models have been trained on documents coming from the Rouen university hospital. This data is not structured and cover a wide range of documents produced in a clinic (discharge summary, prescriptions ...). Four evaluation tasks have been defined (cosine similarity, odd one, mathematical operations and human formal evaluation) and applied on each model. RESULTS Word2Vec had the highest score for three of the four tasks (mathematical operations, odd one similarity and human validation), particularly regarding the Skip-Gram architecture. CONCLUSIONS Even if this implementation had the best rate, each model has its own qualities and defects, like the training time which is very short for GloVe or morphosyntaxic similarity conservation observed with FastText. Models and test sets produced by this study will be the first publicly available through a graphical interface to help advance French biomedical research.

A methodical approach to analyze the effect of river morphology and hydrology on fish fauna in the inner-Alpine space

2021 ◽  
Author(s):  
Katja Schmölz ◽  
Agnes Felber ◽  
Wolfgang Mark ◽  
Melanie Thaler ◽  
Josef Wieser ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Data Entry ◽  
Fish Fauna ◽  
Morphological Characteristics ◽  
Assessment Procedure ◽  
European Alps ◽  
European Guidelines ◽  
Data Entry Form ◽  
Wide Range ◽  
Local Water

<p>River ecosystems are diverse and dynamic habitats which are strongly influenced by direct and indirect consequences of human interventions. Several initiatives have been started all over Europe to fulfill the European guidelines for the protection of the local water bodies, but a standardized procedure fulfilling all relevant aspects and parameters of the Water Framework Directive (WFD) does not exists. To evaluate water quality, the WFD predefines biotic and abiotic parameters, such as morphology, hydrology, water chemistry as well as biological quality components, including fish fauna. In this context, we propose a new methodological approach based on salmonid fish populations to assess river quality. Our approach is based on European standardization of the Austrian and Italian methods and it has been tested in the context of an international fish project in 81 stream sections in the European Alps, having homogeneous morphological characteristics. The assessment procedure is composed of a set of 11 indicators, which were selected to evaluate longitudinal and lateral morphological and hydrological conditions: stream passability, reproduction sites, riverine dynamic, shoreline, shoreline vegetation, structure, substrate and degree of hydrological disturbance, a descent speed indicator as well as discharge conditions of hydropeaking. The indicators were then combined to 3 indices, namely: morphology index (<em>I<sub>M</sub></em>), hydrology index (<em>I<sub>H</sub></em>) and hydromorphology index (<em>I<sub>HM</sub></em>), to create a holistic picture of the total stream conditions. The indicator and index definition, the compilation and practical testing of the data entry form in the field, as well as the calculation of the values, were carried out jointly by a team of experts. The combination of that created a new hydromorphology index (<em>I<sub>HM</sub></em>) for Alpine streams. The application of the proposed method was shown in 31 river streams in South Tyrol (Italy) and Tyrol (Austria) covering a wide range of different anthropogenic changes and pressure degree, which enabled the trial of the methodology and the refinement of the indicators and indices. The outcomes of our study lead to interesting insights regarding applicability, strengths and weaknesses of the proposed approach.</p>

scholarly journals Participatory governance over research in an academic research network: the case of Diabetes Action Canada

BMJ Open ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. e026828 ◽  
Author(s):  
Donald J Willison ◽  
Joslyn Trowbridge ◽  
Michelle Greiver ◽  
Karim Keshavjee ◽  
Doug Mumford ◽  
...  
Keyword(s):  
Clinical Care ◽  
Academic Research ◽  
Digital Data ◽  
Research Network ◽  
Data Governance ◽  
Data Repositories ◽  
Continuous Quality ◽  
Policies And Procedures ◽  
Wide Range ◽  
Governance Process

Digital data generated in the course of clinical care are increasingly being leveraged for a wide range of secondary purposes. Researchers need to develop governance policies that can assure the public that their information is being used responsibly. Our aim was to develop a generalisable model for governance of research emanating from health data repositories that will invoke the trust of the patients and the healthcare professionals whose data are being accessed for health research. We developed our governance principles and processes through literature review and iterative consultation with key actors in the research network including: a data governance working group, the lead investigators and patient advisors. We then recruited persons to participate in the governing and advisory bodies. Our governance process is informed by eight principles: (1) transparency; (2) accountability; (3) follow rule of law; (4) integrity; (5) participation and inclusiveness; (6) impartiality and independence; (7) effectiveness, efficiency and responsiveness and (8) reflexivity and continuous quality improvement. We describe the rationale for these principles, as well as their connections to the subsequent policies and procedures we developed. We then describe the function of the Research Governing Committee, the majority of whom are either persons living with diabetes or physicians whose data are being used, and the patient and data provider advisory groups with whom they consult and communicate. In conclusion, we have developed a values-based information governance framework and process for Diabetes Action Canada that adds value over-and-above existing scientific and ethics review processes by adding a strong patient perspective and contextual integrity. This model is adaptable to other secure data repositories.

Sensitivity of automatic control of emergency manoeuvre to parametric uncertainty of the airplane model

2019 ◽  
Vol 91 (3) ◽  
pp. 407-419
Author(s):  
Jerzy Graffstein ◽  
Piotr Maslowski
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Flight Control ◽  
Parametric Uncertainty ◽  
Second Phase ◽  
Flight Control System ◽  
Content Type ◽  
Control Quality ◽  
Wide Range ◽  
The Impact

Purpose The main purpose of this work was elaboration and verification of a method of assessing the sensitivity of automatic control laws to parametric uncertainty of an airplane’s mathematical model. The linear quadratic regulator (LQR) methodology was used as an example design procedure for the automatic control of an emergency manoeuvre. Such a manoeuvre is assumed to be pre-designed for the selected airplane. Design/methodology/approach The presented method of investigating the control systems’ sensitivity comprises two main phases. The first one consists in computation of the largest variations of gain factors, defined as differences between their nominal values (defined for the assumed model) and the values obtained for the assumed range of parametric uncertainty. The second phase focuses on investigating the impact of the variations of these factors on the behaviour of automatic control in the manoeuvre considered. Findings The results obtained allow for a robustness assessment of automatic control based on an LQR design. Similar procedures can be used to assess in automatic control arrived at through varying design methods (including methods other than LQR) used to control various manoeuvres in a wide range of flight conditions. Practical implications It is expected that the presented methodology will contribute to improvement of automatic flight control quality. Moreover, such methods should reduce the costs of the mathematical nonlinear model of an airplane through determining the necessary accuracy of the model identification process, needed for assuring the assumed control quality. Originality/value The presented method allows for the investigation of the impact of the parametric uncertainty of the airplane’s model on the variations of the gain-factors of an automatic flight control system. This also allows for the observation of the effects of such variations on the course of the selected manoeuvre or phase of flight. This might be a useful tool for the design of crucial elements of an automatic flight control system.

scholarly journals Integral Command Filtered Backstepping Control of a Flexible UAV

2018 ◽  
Vol 160 ◽  
pp. 05005
Author(s):  
Ding Han ◽  
Lin Yan ◽  
Guozheng Yan ◽  
Xiaoliang Wang ◽  
Dengping Duan
Keyword(s):  
Control Systems ◽  
Flight Control ◽  
Research Effort ◽  
Tracking Error ◽  
Rate Of Change ◽  
Body Motion ◽  
Nonlinear Controller ◽  
Integral Action ◽  
Tracking Ability ◽  
Backstepping Controller

Airships, as the significant UAV, have a need for greater autonomy in their new missions. Therefore, airship flight control systems require precise dynamic modeling, taking into account the effect of flexibility and the interaction with aerodynamic forces. This research effort develops an efficient modeling of the autonomous flexible airship. The formalisation used is based on the Lagrange method. The resulting model includes the rigid body motion, the elastic deformation, and the coupling between them. Based on the precise flexible dynamic model, a novel backstepping nonlinear controller with integral action is proposed for motion control systems. The resulting feedback controller is able to adapt to actuator performance limitations, such as limitations in magnitude and rate of change of rudder, than conventional backstepping controller without integral action. With the deformation considered, the presented controller could resist the flexible uncertainty effect, and the system’s trajectory tracking ability is significantly improved. The approach guarantees exponential stability of a compensated tracking error in the sense of Lyapunov.

Effects of the Swirl Velocity of a Jet in Crossflow From Fan Assemblies Mounted on Lifting Surfaces

2010 ◽  
Author(s):  
Alexandros Terzis ◽  
Charilaos Kazakos ◽  
Nikolaos Papadopoulos ◽  
Anestis I. Kalfas ◽  
Pavlos K. Zachos ◽  
...  
Keyword(s):  
Flight Control ◽  
Film Cooling ◽  
Thermal Protection ◽  
Turbine Blades ◽  
Cross Flow ◽  
Vortex Pair ◽  
Main Stream ◽  
Injection Hole ◽  
Swirl Velocity ◽  
Wide Range

The penetration of a jet of fluid into a traversal moving stream is a basic configuration of a wide range of engineering applications, such as film cooling and V/STOL aircrafts. This investigation examines experimentally the effect of blowing ratio of fans in cross flow, and numerically, the effect of the swirl velocity of jets in cross flow, downstream of the injection hole. The experimental results indicated an agreement with typically straight jets in cross flow (no vorticity), illustrating that the trace of the jet, remains close to the wall and subsequently enhance cooling at low blowing ratios in the case of turbine blade applications. However, the rotation of the jet results in an imparity between the two parts of the counter rotating vortex pair (CVP), and as a consequence, the injected fluid not only bends in the direction of the main stream but also diverts in the direction of the rotation, in order to conserve its angular momentum. The induction of the swirl velocity on the injected jet destructs one of the two parts of the kidney vortex which entrains fluid from the cross flow to the jet promoting the mixing between the two fluids, while the trace of a swirled jet remains closer to the wall downstream of the injection hole. Finally, the use of contra rotating jet or fan configurations reduces the wall shear stress in a very great extent, leading to better thermal protection of turbine blades, as well as cancels out the yaw torques of each fan separately, resulting in better flight control of typical lift surface.

scholarly journals Action recognition based on histogram of oriented gradients and spatio-temporal interest points

2018 ◽  
Vol 7 (4) ◽  
pp. 2153
Author(s):  
P A. Dhulekar ◽  
S T. Gandhe
Keyword(s):  
Action Recognition ◽  
Support Vector ◽  
Camera Motion ◽  
Histogram Of Oriented Gradients ◽  
K Nearest Neighbor ◽  
Interest Points ◽  
Human Machine Interaction ◽  
Training Time ◽  
Wide Range ◽  
Spatio Temporal

In modern years large extent of the work has been carried out to recognize human actions perhaps because of its wide range of applications in the field of surveillance, human-machine interaction and video analysis. Several methods were proposed by researchers to resolve action recognition challenges such as variations in viewpoints, occlusion, cluttered backgrounds and camera motion. To address these challenges, we propose a novel method comprise of features extraction using histogram of oriented gradients (HOG), and their classification using k-nearest neighbor (k-NN) and support vector machine (SVM). Six different experimentations were carried out on the basis of hybrid combinations of feature extractors and classifiers. Two gold standard datasets; KTH and Weizmann were used for training and testing purpose. The quantitative parameters such as recognition accuracy, training time and prediction speed were used for evaluation. To validate the applicability of proposed algorithm, its performance has been compared with spatio-temporal interest points (STIP) technique which was proposed as state of art method in the domain. 

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