Steering without Representation with the Use of Active Fixation

Perception ◽  
1997 ◽  
Vol 26 (12) ◽  
pp. 1519-1528 ◽  
Author(s):  
David W Murray ◽  
Ian D Reid ◽  
Andrew J Davison
Keyword(s):  
Human Performance ◽  
Alternative Explanation ◽  
Motor Vehicle ◽  
Gaze Direction ◽  
Tangent Point ◽  
Steering Angle ◽  
Active Fixation ◽  
Quadratic Rule ◽  
Fixation Points ◽  
Moving Fixation

This paper demonstrates the use of active fixation on both fixed and moving fixation points to guide a robot vehicle by means of a steering rule which, at large distances, sets the steering angle directly proportional to the deviation of gaze direction from translation direction. Steering a motor vehicle around a winding but otherwise uncluttered road has been observed by Land and Lee to involve repeated periods of visual fixation upon the tangent point of the inside of each bend. We suggest that proportional rule devised for steering in the robotic example appears applicable to the observed human performance data, providing an alternative explanation to the quadratic rule proposed by Land and Lee.

scholarly journals Quality and Safety of Minimally Invasive Surgery: Past, Present, and Future

2014 ◽  
Vol 6 ◽  
pp. BECB.S10967 ◽  
Author(s):  
Bernadette McCrory ◽  
Chad A. LaGrange ◽  
M.S. Hallbeck
Keyword(s):  
Minimally Invasive Surgery ◽  
Adverse Events ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Human Performance ◽  
Motor Vehicle ◽  
The United States ◽  
Quality And Safety ◽  
Surgical Errors ◽  
The Impact

Adverse events because of medical errors are a leading cause of death in the United States (US) exceeding the mortality rates of motor vehicle accidents, breast cancer, and AIDS. Improvements can and should be made to reduce the rates of preventable surgical errors because they account for nearly half of all adverse events within hospitals. Although minimally invasive surgery (MIS) has proven patient benefits such as reduced postoperative pain and hospital stay, its operative environment imposes substantial physical and cognitive strain on the surgeon increasing the risk of error. To mitigate errors and protect patients, a multidisciplinary approach is needed to improve MIS. Clinical human factors, and biomedical engineering principles and methodologies can be used to develop and assess laparoscopic surgery instrumentation, practices, and procedures. First, the foundational understanding and the imperative to transform health care into a high-quality and safe system is discussed. Next, a generalized perspective is presented on the impact of the design and redesign of surgical technologies and processes on human performance. Finally, the future of this field and the research needed to further improve the quality and safety of MIS is discussed.

Examining Gaze Cone Shape and Size

Perception ◽  
2021 ◽  
pp. 030100662110599
Author(s):  
Gernot Horstmann ◽  
Linda Linke
Keyword(s):  
Present Experiment ◽  
Cone Angle ◽  
Important Task ◽  
Gaze Direction ◽  
Direct Gaze ◽  
The Gaze ◽  
Extended Range ◽  
The Mean ◽  
Fixation Points ◽  
Shape And Size

Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze, that is, the perception of being looked at. The cone of gaze can be defined as the range of fixation points that support direct gaze. The cone concept implies that this range lawfully increases with distance, but that the cone angle is constant. The present experiment tested the concept with a larger number and a more extended range of distances than previously done, and took care of possible directional errors. The gaze cone was found to be roughly linear, and stable between 1.6 m and 7.9 m – an almost perfect cone. The mean cone size subtended 5.2° in diameter when averaged over ascending and descending series. Measures differed, however, in ascending and descending series, consistent with a conservative bias. Also, the variability of judgements increased slightly with distance. Results are discussed considering whether cone size is actually smaller than often reported in the literature.

Objects Capture Perceived Gaze Direction

2006 ◽  
Vol 53 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Janek S. Lobmaier ◽  
Martin H. Fischer ◽  
Adrian Schwaninger
Keyword(s):  
Social Cognition ◽  
Eye Gaze ◽  
Local Features ◽  
Gaze Direction ◽  
Head Orientation ◽  
Gaze Perception ◽  
Mouse Cursor ◽  
Fixation Points ◽  
Normal Adults

The interpretation of another person's eye gaze is a key element of social cognition. Previous research has established that this ability develops early in life and is influenced by the person's head orientation, as well as local features of the person's eyes. Here we show that the presence of objects in the attended space also has an impact on gaze interpretation. Eleven normal adults identified the fixation points of photographed faces with a mouse cursor. Their responses were systematically biased toward the locations of nearby objects. This capture of perceived gaze direction probably reflects the attribution of intentionality and has methodological implications for research on gaze perception.

Occipital Cervical Stabilization Using Occipital Condyles for Cranial Fixation: Technical Case Report

Neurosurgery ◽  
2009 ◽  
Vol 65 (6) ◽  
pp. E1216-E1217 ◽  
Author(s):  
Juan S. Uribe ◽  
Edwin Ramos ◽  
Ali Baaj ◽  
A. Samy Youssef ◽  
Fernando L. Vale
Keyword(s):  
Motor Vehicle ◽  
Motor Vehicle Accident ◽  
Occipital Condyle ◽  
Occipitocervical Fixation ◽  
Vehicle Accident ◽  
Successful Case ◽  
Feasible Option ◽  
Craniocervical Instability ◽  
Fixation Points ◽  
Occipital Condyles

Abstract OBJECTIVE Presentation of a successful case of craniocervical stabilization involving a novel surgical technique using the occipital condyles as the sole cranial fixation points. CLINICAL PRESENTATION A 22-year-old man presented in a delayed fashion with neck pain after a motor vehicle accident. Evaluation revealed a type 2 odontoid fracture with pseudarthrosis and displacement of the dens superiorly and cranial settling of the dens. INTERVENTION The patient underwent posterior occipitocervical fixation with a polyaxial screw rod construct using the occipital condyle, C1 lateral mass, and C2 pars articularis for fixation. The patient had no immediate postoperative deficits. At the time of the 12-month follow-up examination, the patient was neurologically intact with a solid occipitocervical fusion. CONCLUSION Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation points is a feasible option and can be used safely without neurovascular complication in the treatment of craniocervical instability.

Association of pituitary adenoma with neuronal christoma: A TEM study

1994 ◽  
Vol 52 ◽  
pp. 232-233
Author(s):  
Eva Horvath ◽  
Kalman Kovacs ◽  
B. W. Scheithauer ◽  
R. V. Lloyd ◽  
H. S. Smyth
Keyword(s):  
Growth Hormone ◽  
Pituitary Adenoma ◽  
Pituitary Tumor ◽  
Nervous Tissue ◽  
Alternative Explanation ◽  
Growth Hormone Releasing Hormone ◽  
Cell Hyperplasia ◽  
Releasing Hormone ◽  
Secretory Neurons

The association of a pituitary adenoma with nervous tissue consisting of neuron-like cells and neuropil is a rare abnormality. In the majority of cases, the pituitary tumor is a chromophobic adenoma, accompanied by acromegaly. Histology reveals widely variable proportions of endocrine and nervous tissue in alternating or intermingled patterns. The lesion is perceived as a composite one consisting of two histogenetically distinct parts. It has been suggested that the neuronal component, morphologically similar to secretory neurons of the hypothalamus, may initiate adenoma formation by releasing stimulatory substances. Immunoreactivity for growth hormone releasing hormone (GRH) in the neuronal component of some cases supported this view, whereas other findings such as consistent lack of growth hormone (GH) cell hyperplasia in the lesions called for alternative explanation.Fifteen tumors consisting of a pituitary adenoma and a neuronal component have been collected over a 20 yr. period. Acromegaly was present in 11 patients, was equivocal in one, and absent in 3.

The limits of human performance

2008 ◽  
Vol 44 ◽  
pp. 11-26 ◽  
Author(s):  
Ralph Beneke ◽  
Dieter Böning
Keyword(s):  
Human Performance ◽  
Safety Margin ◽  
Afferent Input ◽  
Metabolic Energy ◽  
Human Organism ◽  
Mechanical Resistance ◽  
As Doping ◽  
Gene And Protein Expression ◽  
Underlying Mechanisms ◽  
Biochemical Research

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

Case Exercise: Biomechanics in Rearend Motor Vehicle Collisions

2007 ◽  
Vol 12 (3) ◽  
pp. 4-7
Author(s):  
Charles N. Brooks ◽  
Christopher R. Brigham
Keyword(s):  
Motor Vehicle ◽  
Body Position ◽  
Motor Vehicle Collisions ◽  
Time Curve ◽  
Vehicle Collisions ◽  
Need For Treatment ◽  
Multiple Factors ◽  
Bodily Injury ◽  
Vehicle Collision ◽  
Physical Findings

Abstract Multiple factors determine the likelihood, type, and severity of bodily injury following a motor vehicle collision and, in turn, influence the need for treatment, extent of disability, and likelihood of permanent impairment. Among the most important factors is the change in velocity due to an impact (Δv). Other factors include the individual's strength and elasticity, body position at the time of impact, awareness of the impending impact (ie, opportunity to brace, guard, or contract muscles before an impact), and effects of braking. Because Δv is the area under the acceleration vs time curve, it combines force and duration and is a useful way to quantify impact severity. The article includes a table showing the results of a literature review that concluded, “the consensus of human subject research conducted to date is that a single exposure to a rear-end impact with a Δv of 5 mph or less is unlikely to result in injury” in most healthy, restrained occupants. Because velocity incorporates direction as well as speed, a vehicular occupant is less likely to be injured in a rear impact than when struck from the side. Evaluators must consider multiple factors, including the occupant's pre-existing physical and psychosocial status, the mechanism and magnitude of the collision, and a variety of biomechanical variables. Recommendations based solely on patient history and physical findings (and, perhaps, imaging studies) may be ill-informed.

105: Renal Injury Mechanisms in Motor Vehicle Collisions: Analysis of the Crash Injury Research and Engineering Network (CIREN) Dataset

2007 ◽  
Vol 177 (4S) ◽  
pp. 37-37
Author(s):  
James K. Kuan ◽  
Robert Kaufman ◽  
Jonathan L. Wright ◽  
Charles Mock ◽  
Avery B. Nathens ◽  
...  
Keyword(s):  
Renal Injury ◽  
Motor Vehicle ◽  
Motor Vehicle Collisions ◽  
Vehicle Collisions ◽  
Injury Mechanisms ◽  
Injury Research

1880: Assessment of Basic Human Performance Resources Predicts Performance of Ureterorenoscopy in Human Cadavers

2004 ◽  
Vol 171 (4S) ◽  
pp. 496-497
Author(s):  
Edward D. Matsumoto ◽  
George V. Kondraske ◽  
Lucas Jacomides ◽  
Kenneth Ogan ◽  
Margaret S. Pearle ◽  
...  
Keyword(s):  
Human Performance ◽  
Human Cadavers
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