scholarly journals Microsaccades during high speed continuous visual search

2020 ◽  
Vol 13 (5) ◽  
Author(s):  
Jacob G. Martin ◽  
Charles E. Davis ◽  
Maximilian Riesenhuber ◽  
Simon J. Thorpe

Here, we provide an analysis of the microsaccades that occurred during continuous visual search and targeting of small faces that we pasted either into cluttered background photos or into a simple gray background.  Subjects continuously used their eyes to target singular 3-degree upright or inverted faces in changing scenes.  As soon as the participant’s gaze reached the target face, a new face was displayed in a different and random location.  Regardless of the experimental context (e.g. background scene, no background scene), or target eccentricity (from 4 to 20 degrees of visual angle), we found that the microsaccade rate dropped to near zero levels within only 12 milliseconds after stimulus onset.  There were almost never any microsaccades after stimulus onset and before the first saccade to the face.  One subject completed 118 consecutive trials without a single microsaccade.  However, in about 20% of the trials, there was a single microsaccade that occurred almost immediately after the preceding saccade’s offset.  These microsaccades were task oriented because their facial landmark targeting distributions matched those of saccades within both the upright and inverted face conditions.  Our findings show that a single feedforward pass through the visual hierarchy for each stimulus is likely all that is needed to effectuate prolonged continuous visual search.  In addition, we provide evidence that microsaccades can serve perceptual functions like correcting saccades or effectuating task-oriented goals during continuous visual search.

2020 ◽  
Author(s):  
Jacob G. Martin ◽  
Charles E. Davis ◽  
Maximilian Riesenhuber ◽  
Simon J. Thorpe

ABSTRACTHere, we provide an analysis of the microsaccades that occurred during continuous visual search and targeting of small faces that we pasted either into cluttered background photos or into a simple gray background. Subjects continuously used their eyes to target singular 3-degree upright or inverted faces in changing scenes. As soon as the participant’s gaze reached the target face, a new face was displayed in a different and random location. Regardless of the experimental context (e.g. background scene, no background scene), or target eccentricity (from 4 to 20 degrees of visual angle), we found that the microsaccade rate dropped to near zero levels within only 12 milliseconds after trial onset. There were almost never any microsaccades before the saccade to the face. One subject completed 118 consecutive trials without a single microsaccade. However, in about 20% of the trials, there was a single corrective microsaccade that occurred almost immediately after the preceding saccade’s offset. These corrective microsaccades were task oriented because their facial landmark targeting distributions matched those of saccades within both the upright and inverted face conditions. Our findings show that a single feedforward pass through the visual hierarchy for each stimulus is likely all that is needed to effectuate prolonged continuous visual search. In addition, we provide evidence that microsaccades can serve perceptual functions like correcting saccades or effectuating task-oriented goals during continuous visual search.


2007 ◽  
Vol 10 (2) ◽  
pp. 209-217 ◽  
Author(s):  
Luis Aguado ◽  
Ana Garcia-Gutierrez ◽  
Ester Castañeda ◽  
Cristina Saugar

Priming of affective word evaluation by pictures of faces showing positive and negative emotional expressions was investigated in two experiments that used a double task procedure where participants were asked to respond to the prime or to the target on different trials. The experiments varied between-subjects the prime task assignment and the prime-target interval (SOA, stimulus onset asynchrony). Significant congruency effects (that is, faster word evaluation when prime and target had the same valence than when they were of opposite valence) were observed in both experiments. When the prime task oriented the subjects to an affectively irrelevant property of the faces (their gender), priming was observed at SOA 300 ms but not at SOA 1000 ms (Experiment 1). However, when the prime task assignment explicitly oriented the subjects to the valence of the face, priming was observed at both SOA durations (Experiment 2). These results show, first, that affective priming by pictures of facial emotion can be obtained even when the subject has an explicit goal to process a non-affective property of the prime. Second, sensitivity of the priming effect to SOA duration seems to depend on whether it is mediated by intentional or unintentional activation of the valence of the face prime.


1971 ◽  
Vol 55 (1) ◽  
pp. 13-38 ◽  
Author(s):  
C. J. PENNYCUICK

1. Glide-comparison measurements were made on ten species of East African soaring birds using a Schleicher ASK-14 powered sailplane. Horizontal and vertical speed differences between bird and glider were measured by a photographic method, and used to estimate the bird's horizontal and vertical speeds relative to the air. The analysis refers to the white-backed vulture, since by far the largest number of measurements was obtained on this species. 2. A regression analysis using a two-term approximation to the glide polar yielded an implausibly high estimate of induced drag, which was attributed to a lack of observations at lift coefficients above 0.72. An amended glide polar was constructed assuming elliptical lift distribution and a maximum lift coefficient of 1.6 to define the low-speed end, while the high-speed end was made to pass through the mean horizontal and sinking speeds of all the experimental points. This curve gave a minimum sinking speed of 0.76 m/s at a forward speed of 10 m/s, and a best glide ratio of 15.3:1 at 13 m/s. It did not differ significantly (in the statistical sense) from the original regression curve. 3. In comparing the estimated circling performance, based on the amended glide polar, with that of the ASK-14, it was concluded that the rates of sink of both should be comparable, but that the glider would require thermals with radii about 4.3 times as great as those needed to sustain the birds. The conclusions are consistent with experience of soaring in company with birds. 4. In an attempt to assess the adaptive significance of the low-aspect-ratio wings of birds specializing in thermal soaring, the white-backed vulture's circling performance was compared with that of an ‘albatross-shaped vulture’, an imaginary creature having the same mass as a white-backed vulture, combined with the body proportions of a wandering albatross. It appears that the real white-back would be at an advantage when trying to remain airborne in thermals with radii between 14 and 17 m, but that the albatross-shaped vulture would climb faster in all wider thermals; on account of its much better maximum glide ratio, it should also achieve higher cross-country speeds. It is concluded that the wing shape seen in vultures and storks is not an adaptation to thermal soaring as such, but is more probably a compromise dictated by take-off and landing requirements. 5. The doubts recently expressed by Tucker & Parrott (1970) about the results and conclusions of Raspet (1950a, b; 1960) are re-inforced by the present experience.


Author(s):  
Dilong Guo ◽  
Wen Liu ◽  
Junhao Song ◽  
Ye Zhang ◽  
Guowei Yang

The aerodynamic force acting on the pantograph by the airflow is obviously unsteady and has a certain vibration frequency and amplitude, while the high-speed train passes through the tunnel. In addition to the unsteady behavior in the open-air operation, the compressive and expansion waves in the tunnel will be generated due to the influence of the blocking ratio. The propagation of the compression and expansion waves in the tunnel will affect the pantograph pressure distribution and cause the pantograph stress state to change significantly, which affects the current characteristics of the pantograph. In this paper, the aerodynamic force of the pantograph is studied with the method of the IDDES combined with overset grid technique when high speed train passes through the tunnel. The results show that the aerodynamic force of the pantograph is subjected to violent oscillations when the pantograph passes through the tunnel, especially at the entrance of the tunnel, the exit of the tunnel and the expansion wave passing through the pantograph. The changes of the pantograph aerodynamic force can reach a maximum amplitude of 106%. When high-speed trains pass through tunnels at different speeds, the aerodynamic coefficients of the pantographs are roughly the same.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Maxwell Shinn ◽  
Daeyeol Lee ◽  
John D. Murray ◽  
Hyojung Seo

AbstractIn noisy but stationary environments, decisions should be based on the temporal integration of sequentially sampled evidence. This strategy has been supported by many behavioral studies and is qualitatively consistent with neural activity in multiple brain areas. By contrast, decision-making in the face of non-stationary sensory evidence remains poorly understood. Here, we trained monkeys to identify and respond via saccade to the dominant color of a dynamically refreshed bicolor patch that becomes informative after a variable delay. Animals’ behavioral responses were briefly suppressed after evidence changes, and many neurons in the frontal eye field displayed a corresponding dip in activity at this time, similar to that frequently observed after stimulus onset but sensitive to stimulus strength. Generalized drift-diffusion models revealed consistency of behavior and neural activity with brief suppression of motor output, but not with pausing or resetting of evidence accumulation. These results suggest that momentary arrest of motor preparation is important for dynamic perceptual decision making.


Author(s):  
A. Pinchuk ◽  
M. Garbuz ◽  
P. Zeleny ◽  
D. Harnets ◽  
D. Ivanov

Analysis of combat losses of aircraft in local armed conflicts in recent decades shows that most cases of aircraft hits are related to the impact of guided surface-to-air and air-to-air missiles equipped with homing warheads. The use of modern guided missiles equipped with homing warheads is one of the main threats to aircraft of various types. This is due to the fact that modern guided missiles are characterized by high speed, maneuverability, accuracy of aiming and difficulty of detection. Solving the problem of protecting aircraft from guided missiles consists of several stages: detection of missile launch; confirmation that the detected missile is heading directly toward the protected object; missile identification and decision-making on the most effective countermeasure system employment. At present, there are no missile launch detection systems that guarantee a 100% probability of threat detection, but an analysis of aviation combat losses in local armed conflicts in recent decades convincingly shows that the number of combat losses of aircraft equipped with such systems is much lower than those in which missile launch detection is carried out visually. For example, most of the Soviet Union's losses during the war in Afghanistan and the United States‟ losses during Operation “Desert Storm” in Iraq were related to the use of portable anti-aircraft missile systems, which missiles were equipped with infrared homing warheads. Realizing the scale of the threat posed by such missiles, most of the world's leading countries have significantly increased the expenses on development new or improvement existing countermeasures. As a result, the aggregate losses of coalition forces in Iraq, Afghanistan and Syria since 2001 clearly suggest that these costs have paid off, with losses from the use of portable anti-aircraft missile systems significantly reduced, while the total number of combat sorties increased. Therefore, in the face of all the challenges and threats posed to Ukraine due to the aggressive actions of the Russian Federation, conducting research in the interests of aviation of the Armed Forces of Ukraine to improve the effectiveness of missile detection systems for ensuring timely detection of threats, warning of aircraft crew and activation in the automatic mode the means of countermeasures is as relevant as ever.


2019 ◽  
Vol 5 (3) ◽  
pp. 36-44
Author(s):  
Viktor A. Bogachev ◽  
Yuri A. Terentyev ◽  
Viktor V. Koledov ◽  
Taras V. Bogachev

Background: Research is ongoing relating to the analysis of a set of issues that arise in connection with the creation of the operating on the basis of vacuum magnetic technologies a transcontinental high-speed land transport corridor, connecting the eastern regions of China with Russia. As part of the variation calculus task, the geopolitical, economic, social, logistic, geographic, geomorphological, seismological, topographic components of the project are considered, in which it is assumed that the high speed overland route will pass through the north-western part of the historical region of Dzungaria. Aim: Find the most optimal from the point of view of the above components the location of the most important section of high speed overland route passing through Central Asia. Methods: Variational methods for solving an optimization problem with the use of a computer math system. Results: After creating a fairly informative and versatile picture of the region in question, the foundations of the corresponding mathematical models are built. Conclusion: The New Dzungarian Gates is a key element in choosing the location of a high-speed overland route based on VMLT.


Author(s):  
Zhaijun Lu ◽  
Weijia Huang ◽  
Mu Zhong ◽  
Dongrun Liu ◽  
Tian Li ◽  
...  

Real-time monitoring of overturning coefficients is very important for ensuring the safety of high-speed trains passing through complex terrain sections under strong wind conditions. In recent years, the phenomenon of “car swaying” that occurs when trains pass through the complex terrain has brought new challenges to ensuring the safety and riding comfort of passengers. In China, more and more high-speed trains are facing strong wind environments when running in complex terrain sections. However, due to the limitation of objective conditions, so far, only a few economical and effective methods of measurement have been developed that are suitable for real-time monitoring of the overturning coefficient of commercial vehicles. Therefore, considering the applicability and universality of such a monitoring method, this study presents a method for measuring the overturning coefficient of trains using the primary suspension system under strong winds. A vehicle test was carried out to verify the accuracy of the method. The results show that after correction, the overturning coefficient obtained from the primary suspension system is generally consistent with the overturning coefficient obtained from the instrumented wheelset. The method of measuring the overturning coefficient of trains in strong wind environments with the primary suspension system is, thus, proven feasible.


2010 ◽  
Vol 1 (4) ◽  
pp. 32-44
Author(s):  
Amy E. Rock ◽  
Amanda Mullett ◽  
Saad Algharib ◽  
Jared Schaffer ◽  
Jay Lee

In the face of renewed interest in High-Speed Rail (HSR) projects, Ohio is one of several states seeking federal funding to relieve pressure on aging, overburdened highway infrastructure by constructing passenger rail routes between major cities. This paper evaluates the creation of a new rail route in Ohio’s 3-C Corridor utilizing GIS. The authors consider two primary cost factors in construction, slope and land cover, to generate alternative least-cost paths. To assess the importance of the cost factors, two separate paths are created using two different weighting methods for the land cover layer. The land cover is weighted first by difficulty of construction, and second by relative acquisition costs. These two paths are then compared against a path selected by the Ohio Hub Project which uses existing track lines, advantages and disadvantages of each are discussed.


2020 ◽  
pp. 000765032092896
Author(s):  
Daniel Vogler ◽  
Mark Eisenegger

By using social media, corporations can communicate about their corporate social responsibility (CSR) to the public without having to pass through the gatekeeping function of the news media. However, to what extent can corporations influence the public’s evaluation of their CSR activities with social media activities and if the legacy news media still act as the primary agenda setters when it comes to corporate reputation have not yet been thoroughly analyzed in a digitized media environment. This study addressed this research gap by looking at the effect of CSR communication through Facebook and news media coverage of CSR on corporate reputation in Switzerland. The results of this longitudinal study show that the salience and tone of news media coverage of CSR were positively related to corporate reputation, even though the news media coverage about CSR was predominantly negative. Thus, reputation was still strengthened even in the face of negative publicity. No effect of CSR communication through Facebook on corporate reputation was found. The results suggest that legacy news media still were influential in determining how the public evaluates corporations in the digital age.


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