scholarly journals Investigation of GPS Positioning Accuracy Near a Deciduous Forest Area

2021 ◽  
Vol 14(63) (2) ◽  
pp. 43-50
Author(s):  
Atinç PIRTI ◽  
Keyword(s):  
Deciduous Forest ◽  
Forest Area ◽  
Weak Signals ◽  
Positioning Accuracy ◽  
Gps Positioning ◽  
Accuracy And Precision ◽  
And Performance ◽  
Practical Recommendations

This article evaluates the accuracy and performance of GPS positioning near a forest area. In such cases, positions are calculated from weak signals that tend to be less accurate. Moreover, the results show that there were significant differences depending on season (May vs. October) regarding the accuracy and precision of the measured coordinates; also, accuracies were different depending on the seasonal forest characteristics. Therefore, practical recommendations for each case were established in order to help foresters select the most suitable situation. The results indicated that the season was a significant factor for the GPS surveys.

The closed-subpopulation method and estimation of population size from mark-recapture and ancillary data

2000 ◽  
Vol 78 (2) ◽  
pp. 320-326 ◽  
Author(s):  
Frank AM Tuyttens
Keyword(s):  
Population Size ◽  
Ancillary Data ◽  
Mark Recapture ◽  
Animal Populations ◽  
Accuracy And Precision ◽  
Population Size Estimates ◽  
Minimum Number ◽  
Flexible Framework ◽  
And Performance ◽  
Better Than

The algebraic relationships, underlying assumptions, and performance of the recently proposed closed-subpopulation method are compared with those of other commonly used methods for estimating the size of animal populations from mark-recapture records. In its basic format the closed-subpopulation method is similar to the Manly-Parr method and less restrictive than the Jolly-Seber method. Computer simulations indicate that the accuracy and precision of the population estimators generated by the basic closed-subpopulation method are almost comparable to those generated by the Jolly-Seber method, and generally better than those of the minimum-number-alive method. The performance of all these methods depends on the capture probability, the number of previous and subsequent trapping occasions, and whether the population is demographically closed or open. Violation of the assumption of equal catchability causes a negative bias that is more pronounced for the closed-subpopulation and Jolly-Seber estimators than for the minimum-number-alive. The closed-subpopulation method provides a simple and flexible framework for illustrating that the precision and accuracy of population-size estimates can be improved by incorporating evidence, other than mark-recapture data, of the presence of recognisable individuals in the population (from radiotelemetry, mortality records, or sightings, for example) and by exploiting specific characteristics of the population concerned.

scholarly journals Portuguese Football Federation consensus statement 2020: nutrition and performance in football

2021 ◽  
Vol 7 (3) ◽  
pp. e001082
Author(s):  
Rodrigo Abreu ◽  
Pedro Figueiredo ◽  
Paulo Beckert ◽  
José P Marques ◽  
Samuel Amorim ◽  
...  
Keyword(s):  
Sports Medicine ◽  
Scientific Evidence ◽  
Soccer Players ◽  
Football Players ◽  
Sports Science ◽  
Physiological Demands ◽  
And Performance ◽  
Nutritional Strategies ◽  
Practical Constraints ◽  
Practical Recommendations

Nutrition is an undeniable part of promoting health and performance among football (soccer) players. Nevertheless, nutritional strategies adopted in elite football can vary significantly depending on culture, habit and practical constraints and might not always be supported by scientific evidence. Therefore, a group of 28 Portuguese experts on sports nutrition, sports science and sports medicine sought to discuss current practices in the elite football landscape and review the existing evidence on nutritional strategies to be applied when supporting football players. Starting from understanding football’s physical and physiological demands, five different moments were identified: preparing to play, match-day, recovery after matches, between matches and during injury or rehabilitation periods. When applicable, specificities of nutritional support to young athletes and female players were also addressed. The result is a set of practical recommendations that gathered consensus among involved experts, highlighting carbohydrates periodisation, hydration and conscious use of dietary supplements.

scholarly journals Afferent and Efferent Aspects of Mandibular Sensorimotor Control in Adults Who Stutter

2013 ◽  
Vol 56 (6) ◽  
pp. 1774-1788 ◽  
Author(s):  
Ayoub Daliri ◽  
Roman A. Prokopenko ◽  
Ludo Max
Keyword(s):  
Sensorimotor Control ◽  
Group Differences ◽  
Sensitivity Threshold ◽  
Active Movement ◽  
Jaw Movements ◽  
Positioning Accuracy ◽  
Displacement Threshold ◽  
Anatomical Properties ◽  
And Performance ◽  
Movement Differences

Purpose Individuals who stutter show sensorimotor deficiencies in speech and nonspeech movements. For the mandibular system, the authors dissociated the sense of kinesthesia from the efferent control component to examine whether kinesthetic integrity itself is compromised in stuttering or whether deficiencies occur only when generating motor commands. Method The authors investigated 11 stuttering and 11 nonstuttering adults' kinesthetic sensitivity threshold and kinesthetic accuracy for passive jaw movements as well as their minimal displacement threshold and positioning accuracy for active jaw movements. They also investigated the correlation with an anatomical index of jaw size. Results The groups showed no statistically significant differences on sensory measures for passive jaw movements. Although some stuttering individuals performed more poorly than any nonstuttering participants on the active movement tasks, between-group differences for active movements were not statistically significant. Unlike fluent speakers, however, the stuttering group showed a statistically significant correlation between mandibular size and performance in the active and passive near-threshold tasks. Conclusions Previously reported minimal-movement differences were not replicated. Instead, stuttering individuals' performance varied with anatomical properties. These correlational results are consistent with the hypothesis that stuttering participants generate and perceive movements on the basis of less accurate internal models of the involved neuromechanical systems.

scholarly journals National mapping and estimation of forest area by dominant tree species using Sentinel-2 data

2020 ◽  
Author(s):  
Johannes Breidenbach ◽  
Lars T. Waser ◽  
Misganu Debella-Gilo ◽  
Johannes Schumacher ◽  
Johannes Rahlf ◽  
...  
Keyword(s):  
Tree Species ◽  
Deciduous Forest ◽  
National Level ◽  
National Forest Inventory ◽  
Forest Area ◽  
Forest Resource ◽  
Species Specific ◽  
Minimum Numbers ◽  
Generate Model ◽  
Sentinel 2

Nation-wide Sentinel-2 mosaics were used with National Forest Inventory (NFI) plot data for modelling and subsequent mapping of spruce-, pine- and deciduous-dominated forest in Norway at a 16m×16m resolution. The accuracies of the best model ranged between 74% for spruce and 87% for deciduous forest. An overall accuracy of 90% was found on stand level using independent data from more than 42,000 stands. Errors mostly resulting from a forest mask reduced the model accuracies by approximately 10%. The produced map was subsequently used to generate model-assisted (MA) and post stratified (PS) estimates of species-specific forest area. At the national level, efficiencies of the estimates increased by 20% to 50% for MA and up to 90% for PS. Greater minimum numbers of observations constrained the use of PS. For MA estimates of municipalities, efficiencies improved by up to a factor of 8 but were sometimes also less than 1. PS estimates were always equally as or more precise than direct and MA estimates but were applicable in fewer municipalities. The tree species prediction map is part of the Norwegian forest resource map and is used, among others, to improve maps of other variables of interest such as timber volume and biomass.

scholarly journals Network Optimisation and Performance Analysis of a Multistatic Acoustic Navigation Sensor

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5718
Author(s):  
Rohan Kapoor ◽  
Alessandro Gardi ◽  
Roberto Sabatini
Keyword(s):  
Acoustic Waves ◽  
Navigation Systems ◽  
Sound Waves ◽  
Test Volume ◽  
Positioning Accuracy ◽  
Sensor Arrangement ◽  
Pvt Data ◽  
Acoustic Navigation ◽  
And Performance ◽  
Ranging Errors

This paper addresses some of the existing research gaps in the practical use of acoustic waves for navigation of autonomous air and surface vehicles. After providing a characterisation of ultrasonic transducers, a multistatic sensor arrangement is discussed, with multiple transmitters broadcasting their respective signals in a round-robin fashion, following a time division multiple access (TDMA) scheme. In particular, an optimisation methodology for the placement of transmitters in a given test volume is presented with the objective of minimizing the position dilution of precision (PDOP) and maximizing the sensor availability. Additionally, the contribution of platform dynamics to positioning error is also analysed in order to support future ground and flight vehicle test activities. Results are presented of both theoretical and experimental data analysis performed to determine the positioning accuracy attainable from the proposed multistatic acoustic navigation sensor. In particular, the ranging errors due to signal delays and attenuation of sound waves in air are analytically derived, and static indoor positioning tests are performed to determine the positioning accuracy attainable with different transmitter–receiver-relative geometries. Additionally, it is shown that the proposed transmitter placement optimisation methodology leads to increased accuracy and better coverage in an indoor environment, where the required position, velocity, and time (PVT) data cannot be delivered by satellite-based navigation systems.

Weight Loss in Adolescent Wrestlers

1994 ◽  
Vol 6 (3) ◽  
pp. 211-224 ◽  
Author(s):  
Heidi L. Keller ◽  
Stephen E. Tolly ◽  
Patty S. Freedson
Keyword(s):  
Weight Loss ◽  
Health Professionals ◽  
Sports Medicine ◽  
Normal Weight ◽  
Rapid Weight Loss ◽  
Weight Class ◽  
Weight Cycling ◽  
Performance Consequences ◽  
And Performance ◽  
Practical Recommendations

The sport of wrestling often encourages participants to engage in extreme weight loss practices in order to compete in a weight class one to three weight categories below normal weight. This review discusses the prevalence of the problem, methods wrestlers use to accomplish weight loss, and the health and performance consequences of rapid weight loss, with particular emphasis on weight cycling and minimal safe wrestling weight assessment. Some useful and practical recommendations for minimizing extreme weight loss practices are presented. Several state wrestling associations have adjusted their rules and regulations based on recommendations by organizations such as the American College of Sports Medicine to reduce the prevalence of the problem. Nevertheless, extreme weight loss continues to be a concern among health professionals, particularly with regard to health and performance.

XY Stage Capable of Positioning in Submicron Order

1989 ◽  
Vol 1 (4) ◽  
pp. 333-337 ◽  
Author(s):  
Hiroshi Goto ◽  
Keyword(s):  
Structural Features ◽  
Scanning Tunneling ◽  
Measuring Instruments ◽  
Spherical Lens ◽  
Positioning Accuracy ◽  
Precision Measuring ◽  
Positioning Stage ◽  
Guide System ◽  
And Performance ◽  
And Control

With the progress in microelectronic and optoelectronic devices, precision positioning technology has become more and more important. Such technology is indispensable for the positioning operation between the mask and the wafer in super LSI production, precision processing of optical parts such as the non-spherical lens, and in precision measuring instruments such as the scanning tunneling microscope, etc. These devices require positioning accuracy in the order of submicrons (0 .1μm) or subsubmicrons (0.0lμm). To achieve such accuracy, various devices have been made for mechanism and control. The author and others have developed two kinds of positioning stage, an XY stage of a externally pressurized bearing guide system driven by a DC linear motor, and an XY stage of an elastic hinge spring guide system driven by a piezoelectric actuator and we have achieved positioning accuracy of 0.1 to 0.01µm. These two kinds of XY stages will be described below as examples with a description of the structural features and performance as well as the important points of their configuration.

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