scholarly journals A multiple camera position approach for accurate displacement measurement using computer vision

2021 ◽  
Author(s):  
Rolands Kromanis ◽  
Prakash Kripakaran
Keyword(s):  
Suspension Bridge ◽  
Structural Features ◽  
Damage Scenarios ◽  
Multiple Camera ◽  
Video Recordings ◽  
Historical Archive ◽  
Imaging Approach ◽  
Camera Position ◽  
The Mean ◽  
Analysis Of The Images

AbstractEngineers can today capture high-resolution video recordings of bridge movements during routine visual inspections using modern smartphones and compile a historical archive over time. However, the recordings are likely to be from cameras of different makes, placed at varying positions. Previous studies have not explored whether such recordings can support monitoring of bridge condition. This is the focus of this study. It evaluates the feasibility of an imaging approach for condition assessment that is independent of the camera positions used for individual recordings. The proposed approach relies on the premise that spatial relationships between multiple structural features remain the same even when images of the structure are taken from different angles or camera positions. It employs coordinate transformation techniques, which use the identified features, to compute structural displacements from images. The proposed approach is applied to a laboratory beam, subject to static loading under various damage scenarios and recorded using multiple cameras in a range of positions. Results show that the response computed from the recordings are accurate, with 5% discrepancy in computed displacements relative to the mean. The approach is also demonstrated on a full-scale pedestrian suspension bridge. Vertical bridge movements, induced by forced excitations, are collected with two smartphones and an action camera. Analysis of the images shows that the measurement discrepancy in computed displacements is 6%.

scholarly journals Electron microscopy of synthetic myosin filaments. Evidence for cross-bridge. Flexibility and copolymer formation.

1975 ◽  
Vol 67 (1) ◽  
pp. 93-104 ◽  
Author(s):  
T D Pollard
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Structural Features ◽  
Length Frequency ◽  
Single Population ◽  
Skeletal Muscle Myosin ◽  
Distinctive Features ◽  
Myosin Filaments ◽  
The Mean ◽  
Muscle Myosin

Electron micrographs of negatively stained synthetic myosin filaments reveal that surface projections, believed to be the heads of the constituent myosin molecules, can exist in two configurations. Some filaments have the projections disposed close to the filament backbone. Other filaments have all of their projections widely spread, tethered to the backbone by slender threads. Filaments formed from the myosins of skeletal muscle, smooth muscle, and platelets each have distinctive features, particularly their lengths. Soluble mixtures of skeletal muscle myosin with either smooth muscle myosin or platelet myosin were dialyzed against 0.1 M KC1 at pH 7 to determine whether the simultaneous presence of two types of myosin would influence the properties of the filaments formed. In every case, a single population of filaments formed from the mixtures. The resulting filaments are thought to be copolymers of the two types of myosin, for several reasons: (a) their length-frequency distribution is unimodal and differs from that predicted for a simple mixture of two types of myosin filaments; (b) their mean length is intermediate between the mean lengths of the filaments formed separately from the two myosins in the mixture; (c) each of the filaments has structural features characteristic of both of the myosins in the mixture; and (d) their size and shape are determined by the proportion of the two myosins in the mixture.

scholarly journals Ethologische Untersuchungen zur Beschäftigung von Ebern in Besamungsstationen mit Stroh

2004 ◽  
Vol 47 (6) ◽  
pp. 565-574
Author(s):  
S. Rohrmann ◽  
S. Hoy
Keyword(s):  
Significant Influence ◽  
Artificial Insemination ◽  
Bedding Material ◽  
Video Recordings ◽  
Infrared Video ◽  
The Mean ◽  
X 24

Abstract. Title of the paper: Ethological investigations on occupation with the bedding of boars in Artificial Insemination stations Continuous video recordings with infrared video technique and computer supported analysis with OBSERVER program took place with 78 Piétrain boars in three A.I. stations during 3 x 24 hours. The mean percentage of occupation with the bedding during 24 hours was 7.4 ± 4.4 % (= 106.6 minutes) with a minimum of 1.5 % and a maximum of 18.6 %. The factors A.I. station, season and pen size had a significant influence on occupation with straw as bedding material. The percentage of occupation with bedding in winter was 1.8 % higher than in summer. The percentage of occupation with bedding increased with increasing pen size (from 5.5 % to 11.9 %). The differences between the A.I. stations (between 6.4 % and 10.1 % on average) were caused by management, especially by the frequency of the timers feeding, bedding and watering. The more frequent the boars were caused to stand up by feeding, bedding and watering the higher was the percentage of occupation with the bedding.

scholarly journals Non-Lamellar Liquid Crystalline Nanocarriers for Thymoquinone Encapsulation

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 16 ◽  
Author(s):  
Anan Yaghmur ◽  
Boi Vi Tran ◽  
Seyed Moein Moghimi
Keyword(s):  
Liquid Crystalline ◽  
Drug Carriers ◽  
Structural Features ◽  
Drug Induced ◽  
Guest Molecules ◽  
Drug Molecules ◽  
Liquid Crystalline Nanoparticles ◽  
The Mean ◽  
Biological Performance ◽  
Glycerol Monooleate

Owing to their unique structural features, non-lamellar liquid crystalline nanoparticles comprising cubosomes and hexosomes are attracting increasing attention as versatile investigative drug carriers. Background: Depending on their physiochemical characteristics, drug molecules on entrapment can modulate and reorganize structural features of cubosomes and hexosomes. Therefore, it is important to assess the effect of guest molecules on broader biophysical characteristics of non-lamellar liquid crystalline nanoparticles, since drug-induced architectural, morphological, and size modifications can affect the biological performance of cubosomes and hexosomes. Methods: We report on alterations in morphological, structural, and size characteristics of nanodispersions composed from binary mixtures of glycerol monooleate and vitamin E on thymoquinone (a molecule with wide therapeutic potentials) loading. Results: Thymoquinone loading was associated with a slight increase in the mean hydrodynamic nanoparticle size and led to structural transitions from an internal biphasic feature of coexisting inverse cubic Fd3m and hexagonal (H2) phases to an internal inverse cubic Fd3m phase (micellar cubosomes) or an internal inverse micellar (L2) phase (emulsified microemulsions, EMEs). We further report on the presence of “flower-like” vesicular populations in both native and drug-loaded nanodispersions. Conclusions: These nanodispersions have the potential to accommodate thymoquinone and may be considered as promising platforms for the development of thymoquinone nanomedicines.

scholarly journals Profiles of stereotyped behaviour in people with combined sensory impairments and intellectual disabilities

2019 ◽  
Vol 38 (2) ◽  
pp. 168-183 ◽  
Author(s):  
Gitta de Vaan ◽  
Mathijs PJ Vervloed ◽  
Harry Knoors ◽  
Ludo Verhoeven
Keyword(s):  
Intellectual Disabilities ◽  
Distinct Group ◽  
Autism Spectrum ◽  
Stereotyped Behaviour ◽  
Repetitive Behaviours ◽  
Video Recordings ◽  
Sensory Impairments ◽  
The Mean ◽  
Type Frequency ◽  
Stereotyped Behaviours

Stereotyped and repetitive behaviours are characteristics of autism spectrum disorder (ASD) but also occur in individuals with combined intellectual and sensory disabilities. This article looked at the differences in type, frequency, and duration of stereotyped behaviours between individuals with and without ASD in this population. The study included 59 individuals with intellectual disabilities and sensory impairments. The presence of ASD was assessed using Observation of Autism in people with Sensory and Intellectual Disabilities (OASID). Separate from these assessments, video recordings were scored by observers naive to the ASD status of participants for stereotyped and repetitive behaviours. Stereotyped and repetitive behaviours were more prevalent in participants with ASD, though a large proportion of participants without ASD showed them too. Participants with ASD showed, on average, more frequent and in duration longer stereotyped and repetitive behaviours, especially self-injurious behaviours. No differences were found for vocal, motoric, and stereotyped behaviours with objects. The mean duration of each episode of stereotyped behaviour did not differ between groups. Cluster analysis revealed a distinct group of individuals without ASD who showed a high number of stereotyped behaviours.

Shared dynamical features of smooth- and rough-wall boundary-layer turbulence

2016 ◽  
Vol 792 ◽  
pp. 435-469 ◽  
Author(s):  
R. L. Ebner ◽  
Faraz Mehdi ◽  
J. C. Klewicki
Keyword(s):  
Structural Features ◽  
Momentum Equation ◽  
Rough Wall ◽  
Momentum Balance ◽  
Normal Velocity ◽  
Advective Transport ◽  
Vorticity Field ◽  
Wall Flows ◽  
The Mean ◽  
Spanwise Vorticity

The structure of smooth- and rough-wall turbulent boundary layers is investigated using existing data and newly acquired measurements derived from a four element spanwise vorticity sensor. Scaling behaviours and structural features are interpreted using the mean momentum equation based framework described for smooth-wall flows by Klewicki (J. Fluid Mech., vol. 718, 2013, pp. 596–621), and its extension to rough-wall flows by Mehdiet al.(J. Fluid Mech., vol. 731, 2013, pp. 682–712). This framework holds potential relative to identifying and characterizing universal attributes shared by smooth- and rough-wall flows. As prescribed by the theory, the present analyses show that a number of statistical features evidence invariance when normalized using the characteristic length associated with the wall-normal transition to inertial leading-order mean dynamics. On the inertial domain, the spatial size of the advective transport contributions to the mean momentum balance attain approximate proportionality with this length over significant ranges of roughness and Reynolds number. The present results support the hypothesis of Mehdiet al., that outer-layer similarity is, in general, only approximately satisfied in rough-wall flows. This is because roughness almost invariably leaves some imprint on the vorticity field; stemming from the process by which roughness influences (generally augments) the near-wall three-dimensionalization of the vorticity field. The present results further indicate that the violation of outer similarity over regularly spaced spanwise oriented bar roughness correlates with the absence of scale separation between the motions associated with the wall-normal velocity and spanwise vorticity on the inertial domain.

scholarly journals Validation of phlebotomy performance metrics developed as part of a proficiency-based progression initiative to mitigate wrong blood in tube

2020 ◽  
pp. postgradmedj-2019-137254
Author(s):  
Noirin O’Herlihy ◽  
Sarah Griffin ◽  
Patrick Henn ◽  
Robert Gaffney ◽  
Mary Rose Cahill ◽  
...  
Keyword(s):  
Construct Validity ◽  
Performance Metrics ◽  
Working Environment ◽  
Modified Delphi ◽  
Video Recordings ◽  
Performance Metric ◽  
Large Teaching Hospital ◽  
Wide Range ◽  
The Mean ◽  
A Performance

AimsThe purpose of this study was to (1) characterise the procedure of phlebotomy, deconstruct it into its constituent parts and develop a performance metric for the purpose of training healthcare professionals in a large teaching hospital and to (2) evaluate the construct validity of the phlebotomy metric and establish a proficiency benchmark.MethodBy engaging with a multidisciplinary team with a wide range of experience of preanalytical errors in phlebotomy and observing video recordings of the procedure performed in the actual working environment, we defined a performance metric. This was brought to a modified Delphi meeting, where consensus was reached by an expert panel. To demonstrate construct validity, we used the metric to objectively assess the performance of novices and expert practitioners.ResultsA phlebotomy metric consisting of 11 phases and 77 steps was developed. The mean inter-rater reliability was 0.91 (min 0.83, max 0.95). The expert group completed more steps of the procedure (72 vs 69), made fewer errors (19 vs 13, p=0.014) and fewer critical errors (1 Vs 4, p=0.002) than the novice group.ConclusionsThe metrics demonstrated construct validity and the proficiency benchmark was established with a minimum observation of 69 steps, with no critical errors and no more than 13 errors in total.

Large-Scale Seismic Vulnerability Assessment Method for Urban Centres. An Application to the City of Florence

2014 ◽  
Vol 628 ◽  
pp. 49-54 ◽  
Author(s):  
Maurizio Ripepe ◽  
Giorgio Lacanna ◽  
Pauline Deguy ◽  
Mario de Stefano ◽  
Valentina Mariani ◽  
...  
Keyword(s):  
Vulnerability Assessment ◽  
Large Scale ◽  
Seismic Vulnerability ◽  
Risk Mitigation ◽  
Structural Features ◽  
Assessment Method ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Damage Scenarios ◽  
The City

The seismic vulnerability assessment of a building requires a comprehensive knowledge of both building structural features and soils geophysical parameters. To achieve a vulnerability assessment at the urban scale a large amount of data would be necessary, with a consequent involvement of time and economical resources. The aim of this paper is hence to propose a simplified procedure to evaluate the seismic vulnerability of urban centres and possible seismic damage scenarios in order to identify critical areas and/or building typologies to plan future actions of seismic risk mitigation and prevention. The procedure is applied to the outstanding case study of the city of Florence. The research is based on the definition of major building typologies related to construction periods and type of the structural system (masonry or reinforced concrete), the identification of a set of sample buildings, the analysis of the dynamic behaviour and the evaluation of a vulnerability index with an expeditious approach. The obtained results allow to define potential vulnerability and post-event damage scenarios related to the expected levels of peak ground acceleration.

Construction of Multiple Camera Position Measurable Space

2003 ◽  
Vol 2003 (0) ◽  
pp. 48
Author(s):  
N. Ando ◽  
K. Morioka ◽  
S. Takatsuka ◽  
J. Lee ◽  
H. Hashimoto
Keyword(s):  
Measurable Space ◽  
Multiple Camera ◽  
Camera Position

scholarly journals Wind-driven damage localization on a suspension bridge

2016 ◽  
Vol 11 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Marco Domaneschi ◽  
Maria Pina Limongelli ◽  
Luca Martinelli
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Identification ◽  
Structural Response ◽  
Suspension Bridge ◽  
Element Model ◽  
Damage Localization ◽  
Damage Scenarios ◽  
Long Span Bridges ◽  
Long Span

The paper focuses on extending a recently proposed damage localization method, previously devised for structures subjected to a known input, to ambient vibrations induced by an unknown wind excitation. Wind induced vibrations in long-span bridges can be recorded without closing the infrastructure to traffic, providing useful data for health monitoring purposes. One major problem in damage identification of large civil structures is the scarce data recorded on damaged real structures. A detailed finite element model, able to correctly and reliably reproduce the real structure behavior under ambient excitation can be an invaluable tool, enabling the simulation of several different damage scenarios to test the performance of any monitoring system. In this work a calibrated finite element model of an existing long-span suspension bridge is used to simulate the structural response to wind actions. Several damage scenarios are simulated with different location and severity of damage to check the sensitivity of the adopted identification method. The sensitivity to the length and noise disturbances of recorded data are also investigated.

scholarly journals Analysis of incapacitation during +Gz induced loss of consciousness

2021 ◽  
Vol 65 ◽  
pp. 91-96
Author(s):  
MD Sharma ◽  
P Biswal ◽  
N Taneja ◽  
A Agarwal
Keyword(s):  
Air Force ◽  
High Performance ◽  
Age Groups ◽  
Rapid Onset ◽  
Loss Of Consciousness ◽  
Video Recordings ◽  
Operational Capabilities ◽  
Significant Difference ◽  
The Mean ◽  
The Difference

Introduction: Occurrence of G induced loss of consciousness (G-LOC) during centrifuge training is a known entity. The Indian Air Force is currently undertaking high G training of its fighter pilots in High Performance Human Centrifuge (HPHC) which has significantly higher operational capabilities. The study aimed to analyse the incapacitation periods and myoclonic jerks associated with G-LOC occurring during HPHC training. Material and Methods: Records of episodes of 161 G-LOC during closed loop Rapid Onset Rates (ROR) runs over a period of 7 years from 2011 to 2017 were analyzed. The video recordings of these G-LOC episodes were assessed in terms of the participant demographics, +Gz onset rates, incapacitation periods, and presence or absence of myoclonic jerks during the G-LOC episodes. Descriptive statistics was applied to analyze the incapacitation periods and the duration of the myoclonic flail movements. Single tailed t-test was used to analyze the difference between the incapacitation periods of the aircrew who suffered myoclonic flail movements and those who did not. One-way ANOVA was carried out to assess the differences in incapacitation periods, if any, between aircrew of different age groups. Significance was set at P < 0.05. Results: Of these 161 episodes of G-LOC, 43.5% were seen in trainee aircrew. The mean Absolute Incapacitation Period (AIP), Relative Incapacitation Period (RIP) and Total Incapacitation Period (TIP) was 6.9 ± 2.3 s, 12.2 ± 4.7 s, and 19.1 ± 5.5 respectively. Age and flying experience did not show any significant effect with any of the incapacitation periods (p>0.05). The TIP correlated better with the RIP than with the AIP (Pearson’s correlation values of 0.9 and 0.52 respectively). Myoclonic flail movements were witnessed in 25.5% of G-LOC episodes with an average duration of 5.3 s and more than 50% occurring at ≥8Gz. The mean duration of RIP was significantly higher (P=0.03) when G-LOC was associated with myoclonic flail movements, whereas, the duration of AIP did not show any significant difference. Conclusion: The shorter incapacitation periods observed in the study compared to that reported in most of the previous studies could be attributed to the faster Gz offset rates of the present HPHC. Episodes of G-LOC having myoclonic movements were found to have higher relative incapacitation periods. Even though these movements were associated with G-LOC occurring at higher Gz levels, the durations were independent of the Gz levels.

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