Preattentive Processing of Object Size: Implications for Theories of Size Perception

Perception ◽  
1993 ◽  
Vol 22 (10) ◽  
pp. 1175-1193 ◽  
Author(s):  
Geoffrey W Stuart ◽  
Terence R J Bossomaier ◽  
Sue Johnson
Keyword(s):  
Visual Search ◽  
Size Perception ◽  
Viewing Distance ◽  
Frequency Content ◽  
Interference Effects ◽  
Size Discrimination ◽  
Cross Sectional ◽  
Preattentive Processing ◽  
Cross Sectional Size ◽  
Boundary Curvature

Information about the visual angle size of objects is important for maintaining object constancy with variations in viewing distance. Although human observers are quite accurate at judging spatial separations (or cross-sectional size), they are prone to error when there are other spans nearby, as in classical illusions such as the Müller-Lyer illusion. It is possible to reconcile these aspects of size perception by assuming that the size domain is sampled sparsely. It was shown by means of a visual search procedure that the size of objects is processed preattentively and in parallel across the visual field. It was demonstrated that an object's size, rather than its boundary curvature or spatial-frequency content, provides the basis for parallel visual search. It was also shown that texture borders could be substituted for luminance borders, indicating that object boundaries at the relevant spatial scale provide the input to size perception. Parallel processing imposes a severe computational constraint which provides support for the assumption of sparse sampling. An economical model based on several broadly tuned layers of size detectors is proposed to account for the parallel extraction of size, the Weberian behaviour of size discrimination, and the occurrence of strong interference effects in the size domain.

Infrared Diagnostics of Free Charge Carriers in Silicon Nanowires

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940030 ◽  
Author(s):  
A. I. Efimova ◽  
E. A. Lipkova ◽  
K. A. Gonchar ◽  
A. A. Eliseev ◽  
V. Yu. Timoshenko
Keyword(s):  
Silicon Nanowires ◽  
Crystalline Silicon ◽  
Free Charge Carrier ◽  
Charge Carrier Concentration ◽  
Attenuated Total Reflection ◽  
Free Charge ◽  
Cross Sectional ◽  
Text Type ◽  
Cross Sectional Size ◽  
Potential Applications

Free charge carrier concentration in arrays of silicon nanowires (SiNWs) with cross-sectional size of the order of 100[Formula: see text]nm was quantitatively studied by means of the infrared spectroscopy in an attenuated total reflection mode. SiNWs were formed on lightly-doped [Formula: see text]-type crystalline silicon substrates by metal-assisted chemical etching followed by additional doping through thermoactivated diffusion of boron at 900–1000∘C. The latter process was found to increase the concentration of free holes in SiNWs up to [Formula: see text][Formula: see text]cm[Formula: see text]. Potential applications of highly doped SiNWs in thermoelectric energy converters and infrared plasmonic devices are discussed.

Structural Design of a Multifunctional Morphing Fowler Flap for a Twin-Prop Regional Aircraft

2018 ◽  
Author(s):  
Francesco Rea ◽  
Francesco Amoroso ◽  
Rosario Pecora ◽  
Maria Chiara Noviello ◽  
Maurizio Arena
Keyword(s):  
Finite Element ◽  
Analysis Tool ◽  
Load Path ◽  
Element Analysis ◽  
Cross Sectional ◽  
Aerodynamic Performances ◽  
Cross Sectional Size ◽  
Elementary Methods ◽  
Minimum Number ◽  
Mode 3

In the framework of Clean Sky 2 Airgreen 2 (REG-IADP) European research project, a novel multifunctional morphing flap technology was investigated to improve the aerodynamic performances of the next Turboprop regional aircraft (90 passengers) along its flight mission. The proposed true-scale device (5 meters span with a mean chord of 0.6 meters) is conceived to replace and enhance conventional Fowler flap with new functionalities. Three different functions were enabled: overall airfoil camber morphing up to +30° (mode 1), +10°/−10° (upwards/downwards) deflections of the flap tip segment (mode 2), flap tip “segmented” twist of ±5° along the outer flap span (mode 3). Morphing mode 1 is supposed to be activated during take-off and landing only to enhance aircraft high-lift performances and steeper initial climb and descent. Thanks to this function, more airfoil shapes are available at each flap setting and therefore a dramatic simplification of the flap deployment system may be implemented. Morphing modes 2 and 3 are enabled in cruise and off-design flight conditions to improve wing aerodynamic efficiency. The novel structural concept of the three-modal morphing Fowler flap (3MMF) was designed according to the challenges posed by real wing installation issues. The proposed concept consists of a multi-box arrangement activated by segmented ribs with embedded inner mechanisms to realize the transition from the baseline configuration to different target aero-shapes while withstanding the aerodynamic loads. Lightweight and compact actuating leverages driven by electromechanical motors were properly synthesized to comply with stringent requirements for real aircraft implementation: minimum actuating torque, minimum number of motors, reduced weight, and available design space. The methodology for the kinematic design of the inner mechanisms is based on a building block approach where the instant center analysis tool is used to preliminary select the locations of the hinges’ leverages. The final geometry of the inner mechanisms is optimized to maximize the mechanical advantage as well as to provide the kinematic performances required by the three different morphing modes. The load-path was evaluated, and the cross-sectional size of leverages was subsequently optimized. Finally, actuating torques predicted by instant center analysis were compared to the calculated values from finite element analysis. The structural sizing process of the multi-box arrangement was carried out considering elementary methods, and results were compared with finite element simulations.

scholarly journals Musculoskeletal Symptoms among Radiologists in Saudi Arabia: A Multi-Center Cross-Sectional Study

2019 ◽  
Author(s):  
Malak Al Shammari ◽  
Ali Hassan ◽  
Omran Al Dandan ◽  
Mohammed Al Gadeeb ◽  
Dalal Bubshait
Keyword(s):  
Logistic Regression ◽  
Saudi Arabia ◽  
Regression Analysis ◽  
Logistic Regression Analysis ◽  
Online Survey ◽  
Multivariate Logistic Regression Analysis ◽  
Musculoskeletal Symptoms ◽  
Body Region ◽  
Viewing Distance ◽  
Cross Sectional

Abstract Background : Musculoskeletal symptoms account for the majority of work-related illnesses resulting in a significant economic burden on society. Computer users are subject to unique repetitive strains that predispose them to musculoskeletal symptoms. In the digitalized field of radiology, radiologists spend long hours interpreting medical images on computers. This study aimed to determine the prevalence of musculoskeletal symptoms among radiologists in Saudi Arabia and their contributing factors. Methods : An online survey was sent to radiologists in all hospitals (academic, public and private) in the major cities of the Eastern Province of Saudi Arabia covering demographic characteristics, workload (e.g. the time spent at a computer workstation), and workstation environments including the number of monitors as well as the adjustability of the height of the workstation and the viewing distance. This survey of 263 radiologists was conducted in April 2019. It included an evaluation of musculoskeletal symptoms using the Nordic Musculoskeletal Questionnaire. The study outcome was the presence of disabling musculoskeletal symptoms in any body region, which restricted the performance of normal activities in the last 12 months. Results were analyzed descriptively using a Chi-square test and logistic regression analysis to estimate the odd ratio of experiencing disabling musculoskeletal symptoms in the last 12 months. Results : The survey was completed by 198 participants (111 men and 87 women) with a response rate of 75.3%. Most participants (71.2%) were aged below 40 years. A multivariate logistic regression analysis revealed being a female radiologist (OR = 2.7; 95% CI: 1.2–6.5), aged 30–39 years (OR = 4.1; 95% CI: 1.1–15.3), and predominantly reviewing computed tomography (CT) images (OR = 4.1; 95% CI: 1.4–12.3) or ultrasound scans (OR = 5.9; 95% CI: 1.4–25.3) were associated with higher prevalence of disabling musculoskeletal symptoms, compared to those aged below 30 years and those who reviewed various imaging modalities, respectively. Conclusions : Musculoskeletal symptoms are common among radiologists with lower back and neck pain being the most frequent complaints. Being a female radiologist, aged 30–39 years, and reviewing CT or ultrasound scans were associated with higher rates of disabling musculoskeletal symptoms.

scholarly journals Musculoskeletal symptoms among radiologists in Saudi Arabia: a multi-center cross-sectional study

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Malak Al Shammari ◽  
Ali Hassan ◽  
Omran Al Dandan ◽  
Mohammed Al Gadeeb ◽  
Dalal Bubshait
Keyword(s):  
Logistic Regression ◽  
Saudi Arabia ◽  
Regression Analysis ◽  
Logistic Regression Analysis ◽  
Online Survey ◽  
Multivariate Logistic Regression Analysis ◽  
Musculoskeletal Symptoms ◽  
Body Region ◽  
Viewing Distance ◽  
Cross Sectional

Abstract Background Musculoskeletal symptoms account for the majority of work-related illnesses resulting in a significant economic burden on society. Computer users are subject to unique repetitive strains that predispose them to musculoskeletal symptoms. In the digitalized field of radiology, radiologists spend long hours interpreting medical images on computers. This study aimed to determine the prevalence of musculoskeletal symptoms among radiologists in Saudi Arabia and their contributing factors. Methods An online survey was sent to radiologists in all hospitals (academic, public and private) in the major cities of the Eastern Province of Saudi Arabia covering demographic characteristics, workload (e.g. the time spent at a computer workstation), and workstation environments including the number of monitors as well as the adjustability of the height of the workstation and the viewing distance. This survey of 263 radiologists was conducted in April 2019. It included an evaluation of musculoskeletal symptoms using the Nordic Musculoskeletal Questionnaire. The study outcome was the presence of disabling musculoskeletal symptoms in any body region, which restricted the performance of normal activities in the last 12 months. Results were analyzed descriptively using a Chi-square test and logistic regression analysis to estimate the odd ratio of experiencing disabling musculoskeletal symptoms in the last 12 months. Results The survey was completed by 198 participants (111 men and 87 women) with a response rate of 75.3%. Most participants (71.2%) were aged below 40 years. A multivariate logistic regression analysis revealed being a female radiologist (OR = 2.7; 95% CI: 1.2–6.5), aged 30–39 years (OR = 4.1; 95% CI: 1.1–15.3), and predominantly reviewing computed tomography (CT) images (OR = 4.1; 95% CI: 1.4–12.3) or ultrasound scans (OR = 5.9; 95% CI: 1.4–25.3) were associated with higher prevalence of disabling musculoskeletal symptoms, compared to those aged below 30 years and those who reviewed various imaging modalities, respectively. Conclusions Musculoskeletal symptoms are common among radiologists with lower back and neck pain being the most frequent complaints. Being a female radiologist, aged 30–39 years, and reviewing CT or ultrasound scans were associated with higher rates of disabling musculoskeletal symptoms.

Curved Versus Flat Monitors: Interactive Effects of Display Curvature Radius and Display Size on Visual Search Performance and Visual Fatigue

2020 ◽  
pp. 001872082092271
Author(s):  
Gyouhyung Kyung ◽  
Sungryul Park
Keyword(s):  
Visual Search ◽  
Display Size ◽  
Interactive Effects ◽  
Curvature Radius ◽  
Viewing Distance ◽  
Search Performance ◽  
Visual Fatigue ◽  
Visual Display Terminal ◽  
Search Tasks ◽  
Curved Displays

Objective The aim of this study is to examine the interactive effects of display curvature radius and display size on visual search accuracy, visual search speed, and visual fatigue. Background Although the advantages of curved displays have been reported, little is known about the interactive effects of display curvature radius and size. Method Twenty-seven individuals performed visual search tasks at a viewing distance of 50 cm using eight configurations involving four display curvature radii (400R, 600R, 1200R, and flat) and two display sizes (33″ and 50″). To simulate curved screens, five flat display panels were horizontally arranged with their centers concentrically repositioned following each display curvature radius. Results For accuracy, speed, and fatigue, 33″–600R and 50″–600R provided the best or comparable-to-best results, whereas 50″–flat provided the worst results. For accuracy and fatigue, 33″–flat was the second worst. The changes in the horizontal field of view and viewing angle due to display curvature as well as the association between effective display curvature radii and empirical horopter (loci of perceived equidistance) can explain these results. Conclusion The interactive effects of display curvature radius and size were evident for visual search performance and fatigue. Beneficial effects of curved displays were maintained across 33″ and 50″, whereas increasing flat display size from 33″ to 50″ was detrimental. Application For visual search tasks at a viewing distance of 50 cm, 33″–600R and 50″ 600R displays are recommended, as opposed to 33″ and 50″ flat displays. Wide flat displays must be carefully considered for visual display terminal tasks.

scholarly journals Body size dissatisfaction among young Chinese children in Hong Kong: a cross-sectional study

2014 ◽  
Vol 18 (6) ◽  
pp. 1067-1074 ◽  
Author(s):  
Gemma Knowles ◽  
Fiona Chun Man Ling ◽  
G Neil Thomas ◽  
Peymane Adab ◽  
Alison M McManus
Keyword(s):  
Body Image ◽  
Hong Kong ◽  
Body Size ◽  
Weight Status ◽  
Strong Predictor ◽  
Chinese Children ◽  
Size Perception ◽  
Cross Sectional ◽  
Female Sex ◽  
Body Size Dissatisfaction

AbstractObjectiveTo determine the potential predictors of body size dissatisfaction in Chinese children.DesignThe Child’s Body Image Scale was used to assess body size perception and dissatisfaction. BMI was calculated from objectively measured height and weight. Predictors of body size dissatisfaction were examined by logistic regression analysis.SettingHong Kong, China.SubjectsSix hundred and twenty children (53 % boys, aged 6·1–12·9 years) from a state-run primary school.ResultsFemale sex (adjusted OR (AOR)=1·91; 95 % CI 1·32, 2·76), age (AOR=2·62; 95 % CI 1·65, 4·16 for 8–10 years; AOR=2·16; 95 % CI 1·38, 3·38 for >10 years), overweight (AOR=6·23; 95 % CI 3·66, 10·60) and obesity (AOR=19·04; 95 % CI 5·64, 64·32) were positively associated with desire to be thinner. Size misperception was a strong predictor of body size dissatisfaction, irrespective of actual weight status (AOR=1·90; 95 % CI 1·02, 3·54 for overestimation; AOR=0·43; 95 % CI 0·27, 0·67 for underestimation).ConclusionsBody size dissatisfaction is prevalent among Chinese children as young as 6 years. Female sex, age, overweight, obesity and overestimation of size were associated with increased desire to be thinner. These findings emphasise the importance of preventing body image issues from an early age.

Modeling growth stocks via birth-death processes

2003 ◽  
Vol 35 (3) ◽  
pp. 641-664 ◽  
Author(s):  
S. C. Kou ◽  
S. G. Kou
Keyword(s):  
Size Distribution ◽  
Death Process ◽  
Cross Sectional ◽  
Share Prices ◽  
Cross Sectional Size ◽  
High Volatility ◽  
Growth Stocks ◽  
Future Growth ◽  
Modeling Growth ◽  
Birth Death

The inability to predict the future growth rates and earnings of growth stocks (such as biotechnology and internet stocks) leads to the high volatility of share prices and difficulty in applying the traditional valuation methods. This paper attempts to demonstrate that the high volatility of share prices can nevertheless be used in building a model that leads to a particular cross-sectional size distribution. The model focuses on both transient and steady-state behavior of the market capitalization of the stock, which in turn is modeled as a birth-death process. Numerical illustrations of the cross-sectional size distribution are also presented.

Study on Fatigue Properties of Double-Wall-Brazed-Tube

2011 ◽  
Vol 105-107 ◽  
pp. 1644-1647
Author(s):  
Qi Rong Zhu ◽  
Ming Ru Xie ◽  
Xiao Hua Li
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Fatigue Testing ◽  
Shaking Table ◽  
Fatigue Properties ◽  
Metal Fatigue ◽  
Cross Sectional ◽  
Data Analysis Procedure ◽  
Cross Sectional Size ◽  
Double Wall

This paper is referred to other literature on properties of metal fatigue testing methods and data analysis procedure methods. According to high cycle fatigue testing, double-wall-brazed-tube is loaded with different stimulated vibration force by shaking table and is forced to vibrate. In the experience, strain of key parts is measured with Electrical resistance Strain measurement Methods. By curve fitting of experimental data, we gain the fitting function of the specimen’s fatigue life and draw its S-N curve. In accordance with the analysis of experimental data and S-N curves, it is concluded that fatigue properties of metallic materials can not fully reflect fatigue properties of a specimen and that the cross-sectional size of a specimen has much effects on its fatigue life.

Size Discrimination with Low Spatial Frequencies

Perception ◽  
1982 ◽  
Vol 11 (6) ◽  
pp. 707-720 ◽  
Author(s):  
Robert A Smith
Keyword(s):  
Fourier Spectrum ◽  
Low Frequency ◽  
Current Theory ◽  
Size Perception ◽  
Size Discrimination ◽  
Low Frequencies ◽  
Spatial Frequencies ◽  
Vertical Bars ◽  
The Fourier Transform ◽  
Visual Size

The hypothesis that visual size is determined from the low-frequency Fourier spectrum of the image has been tested in a variety of ways. The fact that size discrimination of vertical bars is unimpaired when high spatial frequencies are filtered out of the image by blurring, and the fact that spatial-frequency adaptation alters perceived size, argue in favor of such hypothesis. However, the hypothesis is weakened by the observation that discrimination is also unimpaired by filtering low frequencies out of the image and by the observation that some manipulations which alter the Fourier transform produce no corresponding perceptual change. No current theory of size perception appears to fit all of these data.

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