Obstacle crossing with dual tasking is a danger for individuals with Alzheimer's disease and for healthy older people.

PubMed

Simieli, Lucas; Barbieri, Fabio Augusto; Orcioli-Silva, Diego; Lirani-Silva, Ellen; Stella, Florindo; Gobbi, Lilian Teresa Bucken

2015-01-01

The aim of this study was to analyze the effects of dual tasking on obstacle crossing during walking by individuals with Alzheimer's disease (AD) and by healthy older people. Thirty four elderly individuals (16 healthy subjects and 18 individuals with AD) were recruited to participate in this study. Three AD individuals and one control participant were excluded due to exclusion criteria. The participants were instructed to walk barefoot at their own speed along an 8 m long pathway. Each participant performed five trials for each condition (unobstructed walking, unobstructed walking with dual tasking, and obstacle crossing during walking with dual tasking). The trials were completely randomized for each participant. The mid-pathway stride was measured in the unobstructed walking trials and the stride that occurred during the obstacle avoidance was measured in the trials that involved obstacle crossing. The behavior of the healthy elderly subjects and individuals with AD was similar for obstacle crossing during walking with dual tasking. Both groups used the "posture first" strategy to prioritize stability and showed decreased attention to executive tasking while walking. Additionally, AD had a strong influence on the modifications that are made by the elderly while walking under different walking conditions.

Visual feedback training improves postural adjustments associated with moving obstacle avoidance in elderly women.

PubMed

Hatzitaki, V; Voudouris, D; Nikodelis, T; Amiridis, I G

2009-02-01

The study examined the impact of visually guided weight shifting (WS) practice on the postural adjustments evoked by elderly women when avoiding collision with a moving obstacle while standing. Fifty-six healthy elderly women (70.9+/-5.7 years, 87.5+/-9.6 kg) were randomly assigned into one of three groups: a group that completed 12 sessions (25 min, 3s/week) of WS practice in the Anterior/Posterior direction (A/P group, n=20), a group that performed the same practice in the medio/lateral direction (M/L group, n=20) and a control group (n=16). Pre- and post-training, participants were tested in a moving obstacle avoidance task. As a result of practice, postural response onset shifted closer to the time of collision with the obstacle. Side-to-side WS resulted in a reduction of the M/L sway amplitude and an increase of the trunk's velocity during avoidance. It is concluded that visually guided WS practice enhances elderly's ability for on-line visuo-motor processing when avoiding collision eliminating reliance on anticipatory scaling. Specifying the direction of WS seems to be critical for optimizing the transfer of training adaptations.

Does physical exercise improve obstacle negotiation in the elderly? A systematic review.

PubMed

Guadagnin, Eliane C; da Rocha, Emmanuel S; Duysens, Jacques; Carpes, Felipe P

2016-01-01

Physical exercise improves walking in the elderly but much less is known about its effect on more challenged gait, such as obstacle negotiation. We conducted a systematic review to discuss the effects of regular physical exercise on kinematics and kinetics of obstacle negotiation in the elderly. A comprehensive literature search revealed 859 citations for review, whereof 206 studies entered the full-text analysis. After application of inclusion and exclusion criteria, 13 studies were included in this systematic review. Most of them presented a reasonable quality (average 0.68) but none of them reached the level of a randomized control trial. Interventions were heterogeneous, with training periods lasting from 5 days to 10 months. Studies assessed obstacle negotiation basically considering 3 types of testing paradigm, namely a walkway with either a single obstacle crossing, or with multiple obstacles, or else a treadmill with an obstacle avoidance task under time pressure. In general, longer training programs had better results and very short ones were not effective. A weekly frequency of 2-3 times was the most common among the studies showing positive effects. Regardless of exercises types performed, most of them were effective and so far, there is no consensus about the best exercise for improving obstacle negotiation. A lack of studies on this topic still is evident. Including a record of fall score can further help in deciding which programs are to be preferred. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A national survey of candidates: II: motivations, obstacles, and ideas on increasing interest in psychoanalytic training.

PubMed

Katz, Debra A; Kaplan, Marcia; Stromberg, Sarah E

2012-10-01

A national survey of candidates was conducted to identify motivations for pursuing psychoanalytic training, obstacles that prevent progression or completion, and candidates' ideas on how best to increase interest among potential trainees. In 2009-2010, 40 percent of candidates on the affiliate member e-mail list completed an anonymous web-based survey. Candidates strongly endorsed contact with a personal psychotherapist, psychoanalyst, or supervisor as the most important influence in discovering psychoanalysis and deciding to pursue training. They identified the total cost of analytic training as the greatest obstacle. This was followed by the cost of personal analysis, loss of income for low-fee cases, time away from family, and difficulty finding cases. To enhance training, local institutes should work to improve institute atmosphere and provide assistance with finding cases; national organizations should increase outreach activities and publicize psychoanalysis. Psychoanalytic institutes could recruit future candidates by working to increase personal contact with psychoanalysts, reducing the cost of training, improving institute atmosphere, assisting with case-finding, enhancing outreach activities, and widely publicizing psychoanalysis. Narrative comments from candidates and the implications of these findings regarding engagement of future trainees are discussed.

Stepping over obstacles: gait patterns of healthy young and old adults.

PubMed

Chen, H C; Ashton-Miller, J A; Alexander, N B; Schultz, A B

1991-11-01

Falls associated with tripping over an obstacle can be devastating to elderly individuals, yet little is known about the strategies used for stepping over obstacles by either old or young adults. The gait of gender-matched groups of 24 young and 24 old healthy adults (mean ages 22 and 71 years) was studied during a 4 m approach to and while stepping over obstacles of 0, 25, 51, or 152 mm height and in level obstacle-free walking. Optoelectronic cameras and recorders were used to record approach and obstacle crossing speeds as well as bilateral lower extremity kinematic parameters that described foot placement and movement trajectories relative to the obstacle. The results showed that age had no effect on minimum swing foot clearance (FC) over an obstacle. For the 25 mm obstacle, mean FC was 64 mm, or approximately three times that used in level gait; FC increased nonlinearly with obstacle height for all subjects. Although no age differences were found in obstacle-free gait, old adults exhibited a significantly more conservative strategy when crossing obstacles, with slower crossing speed, shorter step length, and shorter obstacle-heel strike distance. In addition, the old adults crossed the obstacle so that it was 10% further forward in their obstacle-crossing step. Although all subjects successfully avoided the riskiest form of obstacle contact, tripping, 4/24 healthy old adults stepped on an obstacle, demonstrating an increased risk for obstacle contact with age.

Obstacle Course Training Can Improve Mobility and Prevent Falls in People with Intellectual Disabilities

ERIC Educational Resources Information Center

Van Hanegem, E.; Enkelaar, L.; Smulders, E.; Weerdesteyn, V.

2014-01-01

Background: Persons with intellectual disabilities (ID) constitute a special-needs population at high risk of falling. This is the first study to evaluate whether obstacle course training can improve mobility and prevent falls in this population. Methods: The intervention was implemented as part of an institution-wide health care improvement plan…

Aquatic obstacle training improves freezing of gait in Parkinson's disease patients: a randomized controlled trial.

PubMed

Zhu, Zhizhong; Yin, Miaomiao; Cui, Liling; Zhang, Ying; Hou, Weijia; Li, Yaqing; Zhao, Hua

2018-01-01

Our aim was to evaluate the effect of aquatic obstacle training on balance parameters in comparison with a traditional aquatic therapy in patients with Parkinson's disease. A randomized single-blind controlled trial. Outpatients in the rehabilitation department. A total of 46 patients with Parkinson's disease in Hoehn-Yahr stage 2-3. Participants were randomly assigned to (1) aquatic therapy or (2) obstacle aquatic therapy. All participants undertook aquatic therapy for 30 minutes, five times per week for six weeks. The Freezing of Gait Questionnaire, Functional Reach Test, Timed Up and Go test and Berg Balance Scale were assessed at baseline, posttreatment and at six-month follow-up. Both groups of patients had improved primary outcomes after the training program. A between-group comparison of the changes revealed that obstacle aquatic therapy was significantly higher for the Freezing of Gait Questionnaire (after treatment: 8.7 ± 3.3 vs 6.2 ± 2.1, P = 0.004; posttest: 7.7 ± 3.1 vs 5.3 ± 2.0, P = 0.003) and Timed Up and Go test (after treatment: 17.1 ± 2.9 vs 13.8 ± 1.9, P < 0.001; posttest: 16.3 ± 2.8 vs 12.9 ± 1.4, P < 0.001). Obstacle aquatic therapy in this protocol seems to be more effective than traditional protocols for gait and balance in patients with Parkinson's disease, and the effect lasts for six months.

People with stroke who fail an obstacle crossing task have a higher incidence of falls and utilize different gait patterns compared with people who pass the task.

PubMed

Said, Catherine M; Galea, Mary P; Lythgo, Noel

2013-03-01

Obstacle crossing is impaired in people following stroke. It is not known whether people with stroke who fail an obstacle crossing task have more falls or whether the gait adjustments used to cross an obstacle differ from those used by people who pass the task. The purposes of this study were (1) to identify whether a group of people with stroke who failed an obstacle crossing task had a greater incidence of falling and (2) to determine whether people who fail an obstacle crossing task utilize different gait adjustments. This was a prospective, observational study. Thirty-two participants with a recent stroke were recruited. Participants walked at self-selected speed and stepped over a 4-cm-high obstacle. Performance was rated as pass or fail, and spatiotemporal, center of mass (COM), and center of pressure (COP) data were collected. Prospective falls data were recorded for 20 participants over a 6-month period. The incidence of fallers was significantly higher (incidence rate=0.833) in the group that failed the obstacle crossing task than in the group that passed the task (incidence rate=0.143). The group that failed the task had a slower walking speed and greater normalized separation between the trail heel (unaffected support limb) and COM as the affected lead toe cleared the obstacle. This group exhibited greater normalized times from affected lead toe clearance to landing, unaffected trail toe clearance to landing, and affected trail toe-off to toe clearance. The sample size was small, and falls data were available for only 20 participants. Obstacle crossing is an important task to consider in people following stroke and may be useful in identifying those at risk of falls.

The addition of stripes (a version of the 'horizontal-vertical illusion') increases foot clearance when crossing low-height obstacles.

PubMed

Foster, Richard J; Buckley, John G; Whitaker, David; Elliott, David B

2016-07-01

Trips over obstacles are one of the main causes of falling in older adults, with vision playing an important role in successful obstacle negotiation. We determined whether a horizontal-vertical illusion, superimposed onto low-height obstacles to create a perceived increase in obstacle height, increased foot clearances during obstacle negotiation thus reducing the likelihood of tripping. Eleven adults (mean ± 1 SD: age 27.3 ± 5.1 years) negotiated obstacles of varying heights (3, 5, 7 cm) with four different appearance conditions; two were obstacles with a horizontal-vertical illusion (vertical stripes of different thickness) superimposed on the front, one was a plain obstacle and the fourth a plain obstacle with a horizontal black line painted on the top edge. Foot clearance parameters were compared across conditions. Both illusions led to a significant increase in foot clearance when crossing the obstacle, compared to the plain condition, irrespective of obstacle height. Superimposing a horizontal-vertical illusion onto low-height obstacles can increase foot clearance, and its use on the floor section of a double-glazing door frame for example may reduce the incidence of tripping in the home. Practitioner Summary: Low-height obstacles such as the floor section of a double-glazing door frame are potential tripping hazards. In a gait lab-based study we found that a horizontal-vertical illusion superimposed onto low-height obstacles led to significantly higher foot clearances; indicating their potential as a useful safety measure.

Age-associated changes in obstacle negotiation strategies: Does size and timing matter?

PubMed

Maidan, I; Eyal, S; Kurz, I; Geffen, N; Gazit, E; Ravid, L; Giladi, N; Mirelman, A; Hausdorff, J M

2018-01-01

Tripping over an obstacle is one of the most common causes of falls among older adults. However, the effects of aging, obstacle height and anticipation time on negotiation strategies have not been systematically evaluated. Twenty older adults (ages: 77.7±3.4years; 50% women) and twenty young adults (age: 29.3±3.8years; 50% women) walked through an obstacle course while negotiating anticipated and unanticipated obstacles at heights of 25mm and 75mm. Kinect cameras captured the: (1) distance of the subject's trailing foot before the obstacles, (2) distance of the leading foot after the obstacles, (3) clearance of the leading foot above the obstacles, and (4) clearance of the trailing foot above the obstacles. Linear-mix models assessed changes between groups and conditions. Older adults placed their leading foot closer to the obstacle after landing, compared to young adults (p<0.001). This pattern was enhanced in high obstacles (group*height interaction, p=0.033). Older adults had lower clearance over the obstacles, compared to young adults (p=0.007). This was more pronounced during unanticipated obstacles (group*ART interaction, p=0.003). The distance of the leading foot and clearance of the trailing foot after the obstacles were correlated with motor, cognitive, and functional abilities. These findings suggest that there are age-related changes in obstacle crossing strategies that are dependent on the specific characteristics of the obstacle. The results have important implications for clinical practice, suggesting that functional exercise should include obstacle negotiation training with variable practice of height and available response times. Further studies are needed to better understand the effects of motor and cognitive abilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Robust obstacle detection for unmanned surface vehicles

NASA Astrophysics Data System (ADS)

Qin, Yueming; Zhang, Xiuzhi

2018-03-01

Obstacle detection is of essential importance for Unmanned Surface Vehicles (USV). Although some obstacles (e.g., ships, islands) can be detected by Radar, there are many other obstacles (e.g., floating pieces of woods, swimmers) which are difficult to be detected via Radar because these obstacles have low radar cross section. Therefore, detecting obstacle from images taken onboard is an effective supplement. In this paper, a robust vision-based obstacle detection method for USVs is developed. The proposed method employs the monocular image sequence captured by the camera on the USVs and detects obstacles on the sea surface from the image sequence. The experiment results show that the proposed scheme is efficient to fulfill the obstacle detection task.

Cross-Training: The Tactical View.

ERIC Educational Resources Information Center

Kaeter, Margaret

1993-01-01

Discusses the advantages of and problems associated with cross-training. Looks at the issue of remuneration and offers examples of how two companies that cross-train presently pay their employees. (JOW)

Spike Train Similarity Space (SSIMS) Method Detects Effects of Obstacle Proximity and Experience on Temporal Patterning of Bat Biosonar

PubMed Central

Accomando, Alyssa W.; Vargas-Irwin, Carlos E.; Simmons, James A.

2018-01-01

Bats emit biosonar pulses in complex temporal patterns that change to accommodate dynamic surroundings. Efforts to quantify these patterns have included analyses of inter-pulse intervals, sonar sound groups, and changes in individual signal parameters such as duration or frequency. Here, the similarity in temporal structure between trains of biosonar pulses is assessed. The spike train similarity space (SSIMS) algorithm, originally designed for neural activity pattern analysis, was applied to determine which features of the environment influence temporal patterning of pulses emitted by flying big brown bats, Eptesicus fuscus. In these laboratory experiments, bats flew down a flight corridor through an obstacle array. The corridor varied in width (100, 70, or 40 cm) and shape (straight or curved). Using a relational point-process framework, SSIMS was able to discriminate between echolocation call sequences recorded from flights in each of the corridor widths. SSIMS was also able to tell the difference between pulse trains recorded during flights where corridor shape through the obstacle array matched the previous trials (fixed, or expected) as opposed to those recorded from flights with randomized corridor shape (variable, or unexpected), but only for the flight path shape in which the bats had previous training. The results show that experience influences the temporal patterns with which bats emit their echolocation calls. It is demonstrated that obstacle proximity to the bat affects call patterns more dramatically than flight path shape. PMID:29472848

Spike Train Similarity Space (SSIMS) Method Detects Effects of Obstacle Proximity and Experience on Temporal Patterning of Bat Biosonar.

PubMed

Accomando, Alyssa W; Vargas-Irwin, Carlos E; Simmons, James A

2018-01-01

Bats emit biosonar pulses in complex temporal patterns that change to accommodate dynamic surroundings. Efforts to quantify these patterns have included analyses of inter-pulse intervals, sonar sound groups, and changes in individual signal parameters such as duration or frequency. Here, the similarity in temporal structure between trains of biosonar pulses is assessed. The spike train similarity space (SSIMS) algorithm, originally designed for neural activity pattern analysis, was applied to determine which features of the environment influence temporal patterning of pulses emitted by flying big brown bats, Eptesicus fuscus . In these laboratory experiments, bats flew down a flight corridor through an obstacle array. The corridor varied in width (100, 70, or 40 cm) and shape (straight or curved). Using a relational point-process framework, SSIMS was able to discriminate between echolocation call sequences recorded from flights in each of the corridor widths. SSIMS was also able to tell the difference between pulse trains recorded during flights where corridor shape through the obstacle array matched the previous trials (fixed, or expected) as opposed to those recorded from flights with randomized corridor shape (variable, or unexpected), but only for the flight path shape in which the bats had previous training. The results show that experience influences the temporal patterns with which bats emit their echolocation calls. It is demonstrated that obstacle proximity to the bat affects call patterns more dramatically than flight path shape.

Measuring the effects of a visual or auditory Stroop task on dual-task costs during obstacle crossing.

PubMed

Worden, Timothy A; Mendes, Matthew; Singh, Pratham; Vallis, Lori Ann

2016-10-01

Successful planning and execution of motor strategies while concurrently performing a cognitive task has been previously examined, but unfortunately the varied and numerous cognitive tasks studied has limited our fundamental understanding of how the central nervous system successfully integrates and executes these tasks simultaneously. To gain a better understanding of these mechanisms we used a set of cognitive tasks requiring similar central executive function processes and response outputs but requiring different perceptual mechanisms to perform the motor task. Thirteen healthy young adults (20.6±1.6years old) were instrumented with kinematic markers (60Hz) and completed 5 practice, 10 single-task obstacle walking trials and two 40 trial experimental blocks. Each block contained 20 trials of seated (single-task) trials followed by 20 cognitive and obstacle (30% lower leg length) crossing trials (dual-task). Blocks were randomly presented and included either an auditory Stroop task (AST; central interference only) or a visual Stroop task (VST; combined central and structural interference). Higher accuracy rates and shorter response times were observed for the VST versus AST single-task trials (p<0.05). Conversely, for the obstacle stepping performance, larger dual task costs were observed for the VST as compared to the AST for clearance measures (the VST induced larger clearance values for both the leading and trailing feet), indicating VST tasks caused greater interference for obstacle crossing (p<0.05). These results supported the hypothesis that structural interference has a larger effect on motor performance in a dual-task situation compared to cognitive tasks that pose interference at only the central processing stage. Copyright © 2016 Elsevier B.V. All rights reserved.

Obstacle Characterization in a Geocrowdsourced Accessibility System

NASA Astrophysics Data System (ADS)

Qin, H.; Aburizaiza, A. O.; Rice, R. M.; Paez, F.; Rice, M. T.

2015-08-01

Transitory obstacles - random, short-lived and unpredictable objects - are difficult to capture in any traditional mapping system, yet they have significant negative impacts on the accessibility of mobility- and visually-impaired individuals. These transitory obstacles include sidewalk obstructions, construction detours, and poor surface conditions. To identify these obstacles and assist the navigation of mobility- and visually- impaired individuals, crowdsourced mapping applications have been developed to harvest and analyze the volunteered obstacles reports from local students, faculty, staff, and residents. In this paper, we introduce a training program designed and implemented for recruiting and motivating contributors to participate in our geocrowdsourced accessibility system, and explore the quality of geocrowdsourced data with a comparative analysis methodology.

Tracked robot controllers for climbing obstacles autonomously

NASA Astrophysics Data System (ADS)

Vincent, Isabelle

2009-05-01

Research in mobile robot navigation has demonstrated some success in navigating flat indoor environments while avoiding obstacles. However, the challenge of analyzing complex environments to climb obstacles autonomously has had very little success due to the complexity of the task. Unmanned ground vehicles currently exhibit simple autonomous behaviours compared to the human ability to move in the world. This paper presents the control algorithms designed for a tracked mobile robot to autonomously climb obstacles by varying its tracks configuration. Two control algorithms are proposed to solve the autonomous locomotion problem for climbing obstacles. First, a reactive controller evaluates the appropriate geometric configuration based on terrain and vehicle geometric considerations. Then, a reinforcement learning algorithm finds alternative solutions when the reactive controller gets stuck while climbing an obstacle. The methodology combines reactivity to learning. The controllers have been demonstrated in box and stair climbing simulations. The experiments illustrate the effectiveness of the proposed approach for crossing obstacles.

Intercultural Sourcebook: Cross-Cultural Training Methods. Volume 2.

ERIC Educational Resources Information Center

Fowler, Sandra M., Ed.; Mumford, Monica G., Ed.

This comprehensive collection of training methods and exercises used by top trainers in the cross-cultural field contains resources essential for cross-cultural learning. This second volume of the collection includes articles by 34 leading cross-cultural trainers and covers new or divergent training methods for cross-cultural skill development and…

Analysis of Core Stability Exercise Effect on the Physical and Psychological Function of Elderly Women Vulnerable to Falls during Obstacle Negotiation.

PubMed

Ko, Dae-Sik; Jung, Dae-In; Jeong, Mi-Ae

2014-11-01

[Purpose] The aim of the present study was to investigate the effects of core stability exercise (CSE) on the physical and psychological functions of elderly women while negotiating general obstacles. [Subjects and Methods] After allocating 10 elderly women each to the core stability training group and the control group, we carried out Performance-Oriented Mobility Assessment (POMA) and measured crossing velocity (CV), maximum vertical heel clearance (MVHC), and knee flexion angle for assessing physical performances. We evaluated depression and fear of falling for assessing psychological functions. [Results] Relative to the control group, the core stability training group showed statistically significant overall changes after the training session: an increase in POMA scores, faster CV, lower MVHC, and a decrease in knee flexion angle. Furthermore, depression and fear of falling decreased significantly. [Conclusion] CSE can have a positive effect on the improvement of physical and psychological performances of older women who are vulnerable to falls as they negotiate everyday obstacles.

Crossing Organizations for Professional Training.

ERIC Educational Resources Information Center

Gans, Cheryl

2002-01-01

Cross training from a variety of organizations can provide camp professionals with new ways of doing things and with proven methods used by others in related fields. The training needs of camp professionals can be met by organizations in the areas of outdoor education, environmental education, experiential learning, and recreation. Certification…

Manipulating the fidelity of lower extremity visual feedback to identify obstacle negotiation strategies in immersive virtual reality.

PubMed

Kim, Aram; Zhou, Zixuan; Kretch, Kari S; Finley, James M

2017-07-01

The ability to successfully navigate obstacles in our environment requires integration of visual information about the environment with estimates of our body's state. Previous studies have used partial occlusion of the visual field to explore how information about the body and impending obstacles are integrated to mediate a successful clearance strategy. However, because these manipulations often remove information about both the body and obstacle, it remains to be seen how information about the lower extremities alone is utilized during obstacle crossing. Here, we used an immersive virtual reality (VR) interface to explore how visual feedback of the lower extremities influences obstacle crossing performance. Participants wore a head-mounted display while walking on treadmill and were instructed to step over obstacles in a virtual corridor in four different feedback trials. The trials involved: (1) No visual feedback of the lower extremities, (2) an endpoint-only model, (3) a link-segment model, and (4) a volumetric multi-segment model. We found that the volumetric model improved success rate, placed their trailing foot before crossing and leading foot after crossing more consistently, and placed their leading foot closer to the obstacle after crossing compared to no model. This knowledge is critical for the design of obstacle negotiation tasks in immersive virtual environments as it may provide information about the fidelity necessary to reproduce ecologically valid practice environments.

Cross-Cultural Communication in Oncology: Challenges and Training Interests.

PubMed

Weber, Orest; Sulstarova, Brikela; Singy, Pascal

2016-01-01

To survey oncology nurses and oncologists about difficulties in taking care of culturally and linguistically diverse patients and about interests in cross-cultural training.
. Descriptive, cross-sectional.
. Web-based survey.
. 108 oncology nurses and 44 oncologists. 
. 31-item questionnaire derived from preexisting surveys in the United States and Switzerland.
. Self-rated difficulties in taking care of culturally and linguistically diverse patients and self-rated interests in cross-cultural training.
. All respondents reported communication difficulties in encounters with culturally and linguistically diverse patients. Respondents considered the absence of written materials in other languages, absence of a shared common language with patients, and sensitive subjects (e.g., end of life, sexuality) to be particularly problematic. Respondents also expressed a high level of interest in all aspects of cross-cultural training (task-oriented skills, background knowledge, reflexivity, and attitudes). Nurses perceived several difficulties related to care of migrants as more problematic than physicians did and were more interested in all aspects of cross-cultural training. 
. The need for cross-cultural training is high among oncology clinicians, particularly among nurses.
. The results reported in the current study may help nurses in decision-making positions and educators in introducing elements of cross-cultural education into oncology curricula for nurses. Cross-cultural training should be offered to oncology nurses.

Improvements in Obstacle Clearance Parameters and Reaction Time Over a Series of Obstacles Revealed After Five Repeated Testing Sessions in Older Adults.

PubMed

Jehu, Deborah A; Lajoie, Yves; Paquet, Nicole

2017-12-21

The purpose of this study was to investigate obstacle clearance and reaction time parameters when crossing a series of six obstacles in older adults. A second aim was to examine the repeated exposure of this testing protocol once per week for 5 weeks. In total, 10 older adults (five females; age: 67.0 ± 6.9 years) walked onto and over six obstacles of varying heights (range: 100-200 mm) while completing no reaction time, simple reaction time, and choice reaction time tasks once per week for 5 weeks. The highest obstacles elicited the lowest toe clearance, and the first three obstacles revealed smaller heel clearance compared with the last three obstacles. Dual tasking negatively impacted obstacle clearance parameters when information processing demands were high. Longer and less consistent time to completion was observed in Session 1 compared with Sessions 2-5. Finally, improvements in simple reaction time were displayed after Session 2, but choice reaction time gradually improved and did not reach a plateau after repeated testing.

Shoulder Injuries in Individuals Who Participate in CrossFit Training.

PubMed

Summitt, Ryan J; Cotton, Ryan A; Kays, Adam C; Slaven, Emily J

CrossFit, a sport and fitness program, has become increasingly popular both nationally and internationally. Researchers have recently identified significant improvements in health and wellness due to CrossFit. However, some individuals assert that CrossFit poses an inherent risk of injury, specifically to the shoulder, due to the intensity of training. Currently, there is limited evidence to support this assertion. Exercises performed during CrossFit do not place the shoulder at greater risk for injury. Injury rates are comparable to other sports of similar intensity. Descriptive survey study. Level 5. An electronic survey was developed and dispersed to approximately 980 individuals who trained in CrossFit gyms. The survey identified demographic data, training characteristics, and the prevalence of injury over a 6-month period in individuals who participated in CrossFit training. A total of 187 (19.1%) individuals completed the survey. Forty-four (23.5%) indicated that they had experienced a shoulder injury during CrossFit training over the previous 6 months. Of those who reported injury, 17 (38.6%) stated that this injury was an exacerbation of a previous injury sustained prior to starting CrossFit. There was no significant relationship between several demographic and training variables and shoulder injury. All shoulder injuries occurred at a rate of 1.94 per 1000 hours training, while "new" shoulder injuries occurred at a rate of 1.18 per 1000 hours training. The most commonly attributed causes of injury were improper form (33.3%) and exacerbation of a previous injury (33.3%). Twenty-five (64.1%) of those who experienced injury reported 1 month or less of training reduction due to the injury. Shoulder injury rates during CrossFit training are comparable to other methods of recreational exercise. Clinicians should be aware of training demands of exercises in CrossFit and modifications for these exercises to safely progress their patients back to participation.

Shoulder Injuries in Individuals Who Participate in CrossFit Training

PubMed Central

Summitt, Ryan J.; Cotton, Ryan A.; Kays, Adam C.; Slaven, Emily J.

2016-01-01

Background: CrossFit, a sport and fitness program, has become increasingly popular both nationally and internationally. Researchers have recently identified significant improvements in health and wellness due to CrossFit. However, some individuals assert that CrossFit poses an inherent risk of injury, specifically to the shoulder, due to the intensity of training. Currently, there is limited evidence to support this assertion. Hypothesis: Exercises performed during CrossFit do not place the shoulder at greater risk for injury. Injury rates are comparable to other sports of similar intensity. Study Design: Descriptive survey study. Level of Evidence: Level 5. Methods: An electronic survey was developed and dispersed to approximately 980 individuals who trained in CrossFit gyms. The survey identified demographic data, training characteristics, and the prevalence of injury over a 6-month period in individuals who participated in CrossFit training. Results: A total of 187 (19.1%) individuals completed the survey. Forty-four (23.5%) indicated that they had experienced a shoulder injury during CrossFit training over the previous 6 months. Of those who reported injury, 17 (38.6%) stated that this injury was an exacerbation of a previous injury sustained prior to starting CrossFit. There was no significant relationship between several demographic and training variables and shoulder injury. All shoulder injuries occurred at a rate of 1.94 per 1000 hours training, while “new” shoulder injuries occurred at a rate of 1.18 per 1000 hours training. The most commonly attributed causes of injury were improper form (33.3%) and exacerbation of a previous injury (33.3%). Twenty-five (64.1%) of those who experienced injury reported 1 month or less of training reduction due to the injury. Conclusion: Shoulder injury rates during CrossFit training are comparable to other methods of recreational exercise. Clinical Relevance: Clinicians should be aware of training demands of exercises

Vision and agility training in community dwelling older adults: incorporating visual training into programs for fall prevention.

PubMed

Reed-Jones, Rebecca J; Dorgo, Sandor; Hitchings, Maija K; Bader, Julia O

2012-04-01

This study aimed to examine the effect of visual training on obstacle course performance of independent community dwelling older adults. Agility is the ability to rapidly alter ongoing motor patterns, an important aspect of mobility which is required in obstacle avoidance. However, visual information is also a critical factor in successful obstacle avoidance. We compared obstacle course performance of a group that trained in visually driven body movements and agility drills, to a group that trained only in agility drills. We also included a control group that followed the American College of Sports Medicine exercise recommendations for older adults. Significant gains in fitness, mobility and power were observed across all training groups. Obstacle course performance results revealed that visual training had the greatest improvement on obstacle course performance (22%) following a 12 week training program. These results suggest that visual training may be an important consideration for fall prevention programs. Copyright © 2011 Elsevier B.V. All rights reserved.

Resident cross-cultural training, satisfaction, and preparedness.

PubMed

Frintner, Mary Pat; Mendoza, Fernando S; Dreyer, Benard P; Cull, William L; Laraque, Danielle

2013-01-01

To describe the diversity of pediatric residents and examine relationships of cross-cultural training experiences with training satisfaction, perceived preparedness for providing culturally effective care, and attitudes surrounding care for underserved populations. A cross-sectional survey was conducted of a national random sample of graduating pediatric residents and an additional sample of minority residents. Using weighted analysis, we used multivariate regression to test for differences in satisfaction, preparedness, and attitudes between residents with more and less cross-cultural experiences during residency, controlling for residents' characteristics and experiences before training. The survey response rate was 57%. Eleven percent were Hispanic, 61% white, 21% Asian, 9% African American, 9% other racial/ethnic groups; 34% grew up in a bi- or multilingual family. Ninety-three percent of residents were satisfied with their residency training, 81% with the instruction they received on health and health care disparities, and 54% on global health issues. Ninety-six percent of residents felt they were prepared to care for patients from diverse backgrounds, but fewer felt prepared to care for families with beliefs at odds with Western medicine (49%) and families who receive alternative or complementary care (37%). Residents with more cross-cultural experiences during residency reported being better prepared than those with less experience to care for families with limited English proficiency (adjusted odds ratio [aOR] 2.11; 95% confidence interval [CI] 1.40-3.17), new immigrants (aOR 1.91; 95% CI 1.32-2.75), and with religious beliefs that might affect clinical care (aOR 1.62; 95% CI 1.13-2.32). Pediatric residents begin their training with diverse cross-cultural backgrounds and experiences. Residency experiences in cross-cultural care contribute to feelings of preparedness to care for diverse US children. Copyright © 2013 Academic Pediatric Association. Published

A Comparison of Surgery and Family Medicine Residents' Perceptions of Cross-Cultural Care Training of Cross-Cultural Care Training

PubMed Central

Jackson, David S; Lin, Susan Y; Park, Elyse R

2010-01-01

The need for physicians formally trained to deliver care to diverse patient populations has been widely advocated. Utilizing a validated tool, Weissman and Betancourt's Cross-Cultural Care Survey, the aim of this current study was to compare surgery and family medicine residents' perceptions of their preparedness and skillfulness to provide high quality cross-cultural care. Past research has documented differences between the two groups' reported impressions of importance and level of instruction received in cross-cultural care. Twenty surgery and 15 family medicine residents participated in the study. Significant differences were found between surgery and family medicine residents on most ratings of the amount of training they received in cross-cultural skills. Specifically, family medicine residents reported having received more training on: 1) determining how patients want to be addressed, 2) taking a social history, 3) assessing their understanding of the cause of illness, 4) negotiating their treatment plan, 5) assessing whether they are mistrustful of the health care system and/or doctor, 6) identifying cultural customs, 7) identifying how patients make decisions within the family, and 8) delivering services through a medical interpreter. One unexpected finding was that surgery residents, who reported not receiving much formal cultural training, reported higher mean scores on perceived skillfulness (i.e. ability) than family medicine residents. The disconnect may be linked to the family medicine residents' training in cultural humility — more knowledge and understanding of cross-cultural care can paradoxically lead to perceptions of being less prepared or skillful in this area. PMID:21225585

Obstacles to nutrition labeling in restaurants.

PubMed

Almanza, B A; Nelson, D; Chai, S

1997-02-01

This study determined the major obstacles that foodservices face regarding nutrition labeling. Survey questionnaire was conducted in May 1994. In addition to demographic questions, the directors were asked questions addressing willingness, current practices, and perceived obstacles related to nutrition labeling. Sixty-eight research and development directors of the largest foodservice corporations as shown in Restaurants & Institutions magazine's list of the top 400 largest foodservices (July 1993). P tests were used to determine significance within a group for the number of foodservices that were currently using nutrition labeling, perceived impact of nutrition labeling on sales, and perceived responsibility to add nutrition labels. Regression analysis was used to determine the importance of factors on willingness to label. Response rate was 45.3%. Most companies were neutral about their willingness to use nutrition labeling. Two thirds of the respondents were not currently using nutrition labels. Only one third thought that it was the foodservice's responsibility to provide such information. Several companies perceived that nutrition labeling would have a potentially negative effect on annual sales volume. Major obstacles were identified as menu or personnel related, rather than cost related. Menu-related obstacles included too many menu variations, limited space on the menu for labeling, and loss of flexibility in changing the menu. Personnel-related obstacles included difficulty in training employees to implement nutrition labeling, and not enough time for foodservice personnel to implement nutrition labeling. Numerous opportunities will be created for dietetics professionals in helping foodservices overcome these menu- or personnel-related obstacles.

Internal Medicine Residents' Perceptions of Cross-Cultural Training

PubMed Central

Park, Elyse R; Betancourt, Joseph R; Miller, Elizabeth; Nathan, Michael; MacDonald, Ellie; Ananeh-Firempong, Owusu; Stone, Valerie E

2006-01-01

BACKGROUND Physicians increasingly face the challenge of managing clinical encounters with patients from a range of cultural backgrounds. Despite widespread interest in cross-cultural care, little is known about resident physicians' perceptions of what will best enable them to provide quality care to diverse patient populations. OBJECTIVES To assess medicine residents' (1) perceptions of cross-cultural care, (2) barriers to care, and (3) training experiences and recommendations. DESIGN, SETTING, AND PATIENTS Qualitative individual interviews were conducted with 26 third-year medicine residents at Massachusetts General Hospital in Boston (response rate = 87%). Interviews were recorded, transcribed, and analyzed. RESULTS Despite significant interest in cross-cultural care, almost all of the residents reported very little training during residency. Most had gained cross-cultural skills through informal learning. A few were skeptical about formal training, and some expressed concern that it is impossible to understand every culture. Challenges to the delivery of cross-cultural care included managing patients with limited English proficiency, who involve family in critical decision making, and who have beliefs about disease that vary from the biomedical model. Residents cited many implications to these barriers, ranging from negatively impacting the patient-physician relationship to compromised care. Training recommendations included making changes to the educational climate and informal and formal training mechanisms. CONCLUSIONS If cross-cultural education is to be successful, it must take into account residents' perspectives and be focused on overcoming residents' cited barriers. It is important to convey that cross-cultural education is a set of skills that can be taught and applied, in a time-efficient manner, rather than requiring an insurmountable knowledge base. PMID:16704391

Railway obstacle detection algorithm using neural network

NASA Astrophysics Data System (ADS)

Yu, Mingyang; Yang, Peng; Wei, Sen

2018-05-01

Aiming at the difficulty of detection of obstacle in outdoor railway scene, a data-oriented method based on neural network to obtain image objects is proposed. First, we mark objects of images(such as people, trains, animals) acquired on the Internet. and then use the residual learning units to build Fast R-CNN framework. Then, the neural network is trained to get the target image characteristics by using stochastic gradient descent algorithm. Finally, a well-trained model is used to identify an outdoor railway image. if it includes trains and other objects, it will issue an alert. Experiments show that the correct rate of warning reached 94.85%.

The effects of cross-training on fitness and injury in women.

PubMed

Grier, Tyson; Canham-Chervak, Michelle; Anderson, Morgan K; Bushman, Timothy T; Jones, Bruce H

2015-01-01

As combat arms occupations become available to women, adequate muscular strength and aerobic endurance will be essential for the completion of physically demanding job-related tasks. Therefore, in addition to US Army Physical Readiness Training, Soldiers will often engage in their own personal physical fitness training programs. To evaluate fitness and injury outcomes for women participating in personal cross-training programs compared to women performing one mode of training or having no personal fitness program. Demographics, physical training activities, physical fitness, and injuries were obtained from surveys administered to female Soldiers in an infantry division. Women were categorized into the following 4 groups based on their personal physical fitness program: cross-training (CT), running only (R), weight training only (WT), and no personal fitness program (NPF). An ANOVA was used to compare physical training, health behaviors, and physical fitness across groups. A χ² test was used to compare injury rates between fitness programs. Risk (%), risk ratios (RR) and 95% confidence intervals (95% CI) were used to determine injury risk. A total of 620 women completed the survey and indicated whether or not they had a personal fitness program (cross-training, n=260; running only, n=93; weight training only, n=86; no personal fitness program, n=181). Average age and body mass index was 26.2±5.8 years and 24.5±3.3 kg/m² respectively with no differences between the 4 fitness groups. The cross-training group had higher physical performance on the muscular endurance (push-ups and sit-ups) portion of the Army physical fitness test (APFT) when compared to the 3 other groups (CT 42 push-ups vs (R 38, WT 35, NPF 36)); (CT 68 sit-ups vs (R 63, WT 62, NPF 62)). For the aerobic endurance (2-mile run) portion of the APFT, the cross-training group had higher performance when compared to those with no personal fitness program (CT 17.4 minutes vs NPF 18.5 minutes). Overall

The quality of visual information about the lower extremities influences visuomotor coordination during virtual obstacle negotiation.

PubMed

Kim, Aram; Kretch, Kari S; Zhou, Zixuan; Finley, James M

2018-05-09

Successful negotiation of obstacles during walking relies on the integration of visual information about the environment with ongoing locomotor commands. When information about the body and environment are removed through occlusion of the lower visual field, individuals increase downward head pitch angle, reduce foot placement precision, and increase safety margins during crossing. However, whether these effects are mediated by loss of visual information about the lower extremities, the obstacle, or both remains to be seen. Here, we used a fully immersive, virtual obstacle negotiation task to investigate how visual information about the lower extremities is integrated with information about the environment to facilitate skillful obstacle negotiation. Participants stepped over virtual obstacles while walking on a treadmill with one of three types of visual feedback about the lower extremities: no feedback, end-point feedback, or a link-segment model. We found that absence of visual information about the lower extremities led to an increase in the variability of leading foot placement after crossing. The presence of a visual representation of the lower extremities promoted greater downward head pitch angle during the approach to and subsequent crossing of an obstacle. In addition, having greater downward head pitch was associated with closer placement of the trailing foot to the obstacle, further placement of the leading foot after the obstacle, and higher trailing foot clearance. These results demonstrate that the fidelity of visual information about the lower extremities influences both feed-forward and feedback aspects of visuomotor coordination during obstacle negotiation.

The nature and prevalence of injury during CrossFit training.

PubMed

Hak, Paul Taro; Hodzovic, Emil; Hickey, Ben

2013-11-22

CrossFit is a constantly varied, high intensity, functional movement strength and conditioning program which has seen a huge growth in popularity around the world since its inception twelve years ago. There has been much criticism as to the potential injuries associated with CrossFit training including rhabdomyolysis and musculoskeletal injuries. However to date no evidence exists in the literature to the injures and rates sustained. The purpose of this study was to determine the injury rates and profiles of CrossFit athletes sustained during routine CrossFit training. An online questionnaire was distributed amongst international CrossFit online forums. Data collected included general demographics, training programs, injury profiles and supplement use. A total of 132 responses were collected with 97 (73.5%) having sustained an injury during CrossFit training. A total of 186 injuries were reported with 9 (7.0%) requiring surgical intervention. An injury rate of 3.1 per 1000 hours trained was calculated. No incidences of rhabdomyolysis were reported. Injury rates with CrossFit training are similar to that reported in the literature for sports such as Olympic weight-lifting, power-lifting and gymnastics and lower than competitive contact sports such as rugby union and rugby league. Shoulder and spine injuries predominate with no incidences of rhabdomyolysis obtained. To our knowledge this is the first paper in the literature detailing the injury rates and profiles with CrossFit participation.

Cross-Country Skiing Injuries and Training Methods.

PubMed

Nagle, Kyle B

2015-01-01

Cross-country skiing is a low injury-risk sport that has many health benefits and few long-term health risks. Some concern exists that cross-country skiing may be associated with a higher incidence of atrial fibrillation; however, mortality rates among skiers are lower than those among the general population. While continuing to emphasize aerobic and anaerobic training, training methods also should promote ski-specific strength training to increase maximum force and its rate of delivery and to build muscular endurance to maintain that power through a race. Multiple tests are available to monitor training progress. Which tests are most appropriate depends on the specific events targeted. In addition to laboratory-based tests, there also are many simpler, more cost-effective tests, such as short time trials, that can be used to monitor training progress and predict performance particularly at the junior skier level where access and cost may be more prohibitive.

Soldier-relevant body borne load impacts minimum foot clearance during obstacle negotiation.

PubMed

Brown, T N; Loverro, K L; Schiffman, J M

2016-07-01

Soldiers often trip and fall on duty, resulting in injury. This study examined ten male soldiers' ability to negotiate an obstacle. Participants had lead and trail foot minimum foot clearance (MFC) parameters quantified while crossing a low (305 mm) and high (457 mm) obstacle with (19.4 kg) and without (6 kg) body borne load. To minimize tripping risk, participants increased lead foot MFC (p = 0.028) and reduced lead (p = 0.044) and trail (p = 0.035) foot variability when negotiating an obstacle with body borne load. While obstacle height had no effect on MFC (p = 0.273 and p = 0.126), placing the trail foot closer to the high obstacle when crossing with body borne load, resulted in greater lead (R = 0.640, b = 0.241, p = 0.046) and trail (R = 0.636, b = 0.287, p = 0.048) MFC. Soldiers, when carrying typical military loads, may be able to minimize their risk of tripping over an obstacle by creating a safety margin via greater foot clearance with reduced variability. Published by Elsevier Ltd.

State-of-the-art technologies for intrusion and obstacle detection for railroad operations

DOT National Transportation Integrated Search

2007-07-01

This report provides an update on the state-of-the-art technologies with intrusion and obstacle detection capabilities for rail rights of way (ROW) and crossings. A workshop entitled Intruder and Obstacle Detection Systems (IODS) for Railroads Requir...

Recognition of an obstacle in a flow using artificial neural networks.

PubMed

Carrillo, Mauricio; Que, Ulices; González, José A; López, Carlos

2017-08-01

In this work a series of artificial neural networks (ANNs) has been developed with the capacity to estimate the size and location of an obstacle obstructing the flow in a pipe. The ANNs learn the size and location of the obstacle by reading the profiles of the dynamic pressure q or the x component of the velocity v_{x} of the fluid at a certain distance from the obstacle. Data to train the ANN were generated using numerical simulations with a two-dimensional lattice Boltzmann code. We analyzed various cases varying both the diameter and the position of the obstacle on the y axis, obtaining good estimations using the R^{2} coefficient for the cases under study. Although the ANN showed problems with the classification of very small obstacles, the general results show a very good capacity for prediction.

How does visual manipulation affect obstacle avoidance strategies used by athletes?

PubMed

Bijman, M P; Fisher, J J; Vallis, L A

2016-01-01

Research examining our ability to avoid obstacles in our path has stressed the importance of visual input. The aim of this study was to determine if athletes playing varsity-level field sports, who rely on visual input to guide motor behaviour, are more able to guide their foot over obstacles compared to recreational individuals. While wearing kinematic markers, eight varsity athletes and eight age-matched controls (aged 18-25) walked along a walkway and stepped over stationary obstacles (180° motion arc). Visual input was manipulated using PLATO visual goggles three or two steps pre-obstacle crossing and compared to trials where vision was given throughout. A main effect between groups for peak trail toe elevation was shown with greater values generated by the controls for all crossing conditions during full vision trials only. This may be interpreted as athletes not perceiving this obstacle as an increased threat to their postural stability. Collectively, findings suggest the athletic group is able to transfer their abilities to non-specific conditions during full vision trials; however, varsity-level athletes were equally reliant on visual cues for these visually guided stepping tasks as their performance was similar to the controls when vision is removed.

Dynamic simulation of train-truck collision at level crossings

NASA Astrophysics Data System (ADS)

Ling, Liang; Guan, Qinghua; Dhanasekar, Manicka; Thambiratnam, David P.

2017-01-01

Trains crashing onto heavy road vehicles stuck across rail tracks are more likely occurrences at level crossings due to ongoing increase in the registration of heavy vehicles and these long heavy vehicles getting caught in traffic after partly crossing the boom gate; these incidents lead to significant financial losses and societal costs. This paper presents an investigation of the dynamic responses of trains under frontal collision on road trucks obliquely stuck on rail tracks at level crossings. This study builds a nonlinear three-dimensional multi-body dynamic model of a passenger train colliding with an obliquely stuck road truck on a ballasted track. The model is first benchmarked against several train dynamics packages and its predictions of the dynamic response and derailment potential are shown rational. A geometry-based derailment assessment criterion is applied to evaluate the derailment behaviour of the frontal obliquely impacted trains under different conditions. Sensitivities of several key influencing parameters, such as the train impact speed, the truck mass, the friction at truck tyres, the train-truck impact angle, the contact friction at the collision zone, the wheel/rail friction and the train suspension are reported.

Obstacles to Disarmament Education. Centre for Peace Studies Occasional Paper No. 6.

ERIC Educational Resources Information Center

Reardon, Betty

Obstacles to disarmament education fall into three general categories: political, perceptual, and pedagogical. At the elementary school level, these obstacles occur because of: (1) a lack of opportunities for cross-cultural experiences; (2) the socialization processes that enforce the belief that a child's culture is superior to and competitive…

Residence time of symmetric random walkers in a strip with large reflective obstacles

NASA Astrophysics Data System (ADS)

Ciallella, Alessandro; Cirillo, Emilio N. M.; Sohier, Julien

2018-05-01

We study the effect of a large obstacle on the so-called residence time, i.e., the time that a particle performing a symmetric random walk in a rectangular (two-dimensional, 2D) domain needs to cross the strip. We observe complex behavior: We find out that the residence time does not depend monotonically on the geometric properties of the obstacle, such as its width, length, and position. In some cases, due to the presence of the obstacle, the mean residence time is shorter with respect to the one measured for the obstacle-free strip. We explain the residence time behavior by developing a one-dimensional (1D) analog of the 2D model where the role of the obstacle is played by two defect sites having smaller probability to be crossed with respect to all the other regular sites. The 1D and 2D models behave similarly, but in the 1D case we are able to compute exactly the residence time, finding a perfect match with the Monte Carlo simulations.

Maximum Power Training and Plyometrics for Cross-Country Running.

ERIC Educational Resources Information Center

Ebben, William P.

2001-01-01

Provides a rationale for maximum power training and plyometrics as conditioning strategies for cross-country runners, examining: an evaluation of training methods (strength training and maximum power training and plyometrics); biomechanic and velocity specificity (role in preventing injury); and practical application of maximum power training and…

Retinal Detachment due to CrossFit Training Injury

PubMed Central

Joondeph, Stephanie A.; Joondeph, Brian C.

2013-01-01

The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions. PMID:24106626

Retinal Detachment due to CrossFit Training Injury.

PubMed

Joondeph, Stephanie A; Joondeph, Brian C

2013-01-01

The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions.

Cross-Level Effects Between Neurophysiology and Communication During Team Training.

PubMed

Gorman, Jamie C; Martin, Melanie J; Dunbar, Terri A; Stevens, Ronald H; Galloway, Trysha L; Amazeen, Polemnia G; Likens, Aaron D

2016-02-01

We investigated cross-level effects, which are concurrent changes across neural and cognitive-behavioral levels of analysis as teams interact, between neurophysiology and team communication variables under variations in team training. When people work together as a team, they develop neural, cognitive, and behavioral patterns that they would not develop individually. It is currently unknown whether these patterns are associated with each other in the form of cross-level effects. Team-level neurophysiology and latent semantic analysis communication data were collected from submarine teams in a training simulation. We analyzed whether (a) both neural and communication variables change together in response to changes in training segments (briefing, scenario, or debriefing), (b) neural and communication variables mutually discriminate teams of different experience levels, and (c) peak cross-correlations between neural and communication variables identify how the levels are linked. Changes in training segment led to changes in both neural and communication variables, neural and communication variables mutually discriminated between teams of different experience levels, and peak cross-correlations indicated that changes in communication precede changes in neural patterns in more experienced teams. Cross-level effects suggest that teamwork is not reducible to a fundamental level of analysis and that training effects are spread out across neural and cognitive-behavioral levels of analysis. Cross-level effects are important to consider for theories of team performance and practical aspects of team training. Cross-level effects suggest that measurements could be taken at one level (e.g., neural) to assess team experience (or skill) on another level (e.g., cognitive-behavioral). © 2015, Human Factors and Ergonomics Society.

Cross-cultural issues in forensic psychiatry training.

PubMed

Layde, Joseph B

2004-01-01

Forensic psychiatry was officially recognized as a subspecialty by the American Board of Medical Specialties in the 1990's. In 1994, the American Board of Psychiatry and Neurology (ABPN) gave its first written examination to certify forensic psychiatrists. In 1996, the Accreditation Council for Graduate Medical Education (ACGME) began to officially accredit one-year residency experiences in forensic psychiatry, which follow a 4-year residency in general psychiatry. The extra year of training, colloquially known as a fellowship, is required for candidates who wish to receive certification in the subspecialty of forensic psychiatry; since 2001, completion of a year of training in a program accredited by ACGME has been required for candidates wishing to take the ABPN forensic psychiatry subspecialty examination. With the formal recognition of the subspecialty of forensic psychiatry comes the need to examine special issues of cultural importance which apply specifically to forensic psychiatry training. This paper examines the current literature on cross-cultural issues in forensic psychiatry, sets out several of the societal reasons for the importance of emphasizing those issues in forensic psychiatric training, and discusses how those issues are addressed in the curriculum of one forensic psychiatry fellowship at the Medical College of Wisconsin (MCW). While much has been written about cross-cultural issues in general psychiatry, very little has appeared in the literature on the topic of cross-cultural issues in forensic psychiatry.

Obstacle avoidance locomotor tasks: adaptation, memory and skill transfer.

PubMed

Kloter, Evelyne; Dietz, Volker

2012-05-01

The aim of this study was to explore the neural basis of adaptation, memory and skill transfer during human stepping over obstacles. Whilst walking on a treadmill, subjects had to perform uni- and bilateral obstacle steps. Acoustic feedback information about foot clearance was provided. Non-noxious electrical stimuli were applied to the right tibial nerve during the mid-stance phase of the right leg, i.e. 'prior' to the right or 'during' the left leg swing over the obstacle. The electromyogram (EMG) responses evoked by these stimuli in arm and leg muscles are known to reflect the neural coordination during normal and obstacle steps. The leading and trailing legs rapidly adapted foot clearance during obstacle steps with small further changes when the same obstacle condition was repeated. This adaptation was associated with a corresponding decrease in arm and leg muscle reflex EMG responses. Arm (but not leg) muscle EMG responses were greater when the stimulus was applied 'during' obstacle crossing by the left leg leading compared with stimulation 'prior' to right leg swing over the obstacle. A corresponding difference existed in arm muscle background EMG. The results indicate that, firstly, the somatosensory information gained by the performance and adaptation of uni- and bilateral obstacle stepping becomes transferred to the trailing leg in a context-specific manner. Secondly, EMG activity in arm and leg muscles parallels biomechanical adaptation of foot clearance. Thirdly, a consistently high EMG activity in the arm muscles during swing over the obstacle is required for equilibrium control. Thus, such a precision locomotor task is achieved by a context-specific, coordinated activation of arm and leg muscles for performance and equilibrium control that includes adaptation, memory and skill transfer. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

One False Move: Training Deployers in Cross-Cultural Negotiations

DTIC Science & Technology

2016-02-28

AU/ACSC/2016 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY ONE FALSE MOVE: TRAINING DEPLOYERS IN CROSS-CULTURAL NEGOTIATIONS by... negotiations while deployed …………….20 vii Abstract In 2015 Secretary of the...Air Force Deborah Lee James directed that members of the Air Force be trained in cross-cultural negotiation skills before deploying. The next step

Design and Evaluation of a Cross-Cultural Training System

NASA Technical Reports Server (NTRS)

Santarelli, Thomas; Stagl, Kevin C.

2011-01-01

Cross-cultural competency, and the underlying communication and affective skills required to develop such expertise, is becoming increasingly important for a wide variety of domains. To address this need, we developed a blended learning platform which combines virtual role-play with tutorials, assessment and feedback. A Middle-Eastern Curriculum (MEC) exemplar for cross-cultural training U.S. military personnel was developed to guide the refinement of an existing game-based training platform. To complement this curriculum, we developed scenario authoring tools to enable end-users to define training objectives, link performance measures and feedback/remediation to these objectives, and deploy experiential scenarios within a game-based virtual environment (VE). Lessons learned from the design and development of this exemplar cross-cultural competency curriculum, as well as formative evaluation results, are discussed. Initial findings suggest that the underlying training technology promotes deep levels of semantic processing of the key information of relevant cultural and communication skills.

Cross-cultural psychiatric residency training: the Oregon experience.

PubMed

Boehnlein, James K; Leung, Paul K; Kinzie, John David

2008-01-01

The purpose of this article is to describe the goals and structure of cross-cultural psychiatric training at Oregon Health and Science University (OHSU). This training in core knowledge, skills, and attitudes of cultural psychiatry over the past three decades has included medical students, residents, and fellows, along with allied mental health personnel. The curriculum includes both didactic sessions devoted to core topics in the field and varied clinical experiences in community settings and the Intercultural Psychiatric Program under the supervision of experienced academic faculty. The authors review the central elements of the training experiences and include a detailed description of the core clinical settings and experiences. At the conclusion of their clinical experiences, trainees have specialized cross-cultural psychiatric knowledge and skills, including treatment of refugees and immigrants, sociocultural variables that influence the assessment and treatment of a wide range of psychiatric conditions, and comfort with cultural dynamics that influence both the doctor/patient relationship and collaboration with a wide range of mental health professionals. Because of rapid demographic changes in the U.S. population, providing cross-cultural training for students, residents, and fellows is an essential foundation for the education of the next generation of clinicians and health care leaders. OHSU has provided a long-term model for this training in a busy clinical and academic setting that places an emphasis on multidisciplinary and multicultural collaboration.

Obstacles to integrated pest management adoption in developing countries

PubMed Central

Parsa, Soroush; Morse, Stephen; Bonifacio, Alejandro; Chancellor, Timothy C. B.; Condori, Bruno; Crespo-Pérez, Verónica; Hobbs, Shaun L. A.; Kroschel, Jürgen; Ba, Malick N.; Rebaudo, François; Sherwood, Stephen G.; Vanek, Steven J.; Faye, Emile; Herrera, Mario A.; Dangles, Olivier

2014-01-01

Despite its theoretical prominence and sound principles, integrated pest management (IPM) continues to suffer from anemic adoption rates in developing countries. To shed light on the reasons, we surveyed the opinions of a large and diverse pool of IPM professionals and practitioners from 96 countries by using structured concept mapping. The first phase of this method elicited 413 open-ended responses on perceived obstacles to IPM. Analysis of responses revealed 51 unique statements on obstacles, the most frequent of which was “insufficient training and technical support to farmers.” Cluster analyses, based on participant opinions, grouped these unique statements into six themes: research weaknesses, outreach weaknesses, IPM weaknesses, farmer weaknesses, pesticide industry interference, and weak adoption incentives. Subsequently, 163 participants rated the obstacles expressed in the 51 unique statements according to importance and remediation difficulty. Respondents from developing countries and high-income countries rated the obstacles differently. As a group, developing-country respondents rated “IPM requires collective action within a farming community” as their top obstacle to IPM adoption. Respondents from high-income countries prioritized instead the “shortage of well-qualified IPM experts and extensionists.” Differential prioritization was also evident among developing-country regions, and when obstacle statements were grouped into themes. Results highlighted the need to improve the participation of stakeholders from developing countries in the IPM adoption debate, and also to situate the debate within specific regional contexts. PMID:24567400

The impact of different cross-training modalities on performance and injury-related variables in high school cross country runners.

PubMed

Paquette, Max R; Peel, Shelby A; Smith, Ross E; Temme, Mark; Dwyer, Jeffrey N

2017-11-29

There are many different types of aerobic cross-training modalities currently available. It is important to consider the effects that these different modalities have on running performance and injury risks. The purpose of this study was to compare movement quality, running economy and performance, injury-related biomechanical variables and, hip muscle strength before and after training with different cross-training modalities in high school runners. Thirty-one high school male runners trained for four weeks in one of three cross-training modalities, in addition to a running-only (RUN, n=9) group, for which training sessions replaced two easy runs per week: cycling (CYCLE; n=6), indoor elliptical (ELLIP; n=7) and, outdoor elliptical bike (EBIKE; n=9). Functional movement screen (FMS), running economy (RE), 3,000m performance, hip kinematics, hip muscle strength were assessed. Paired t-tests and Cohen's d effect sizes were used to assess mean differences for each variable before and after training within each group. EBIKE training was the only modality that improved FMS scores (d = 1.36) and RE before and after training (d = 0.48). All groups showed improvements in 3,000m performance but large effects were only found for the CYCLE (d = 1.50) and EBIKE (d = 1.41) groups. RUN (d = 1.25), CYCLE (d = 1.17) and, EBIKE (d = 0.82) groups showed improvements in maximal hip extensor strength. Outdoor cycling and elliptical bike cross-training may be the most effective cross-training modalities to incorporate in early season training to improve running performance in high school runners.

Safe Maritime Navigation with COLREGS Using Velocity Obstacles

NASA Technical Reports Server (NTRS)

Kuwata, Yoshiaki; Wolf, Michael T.; Zarzhitsky, Dimitri; Huntsberger, Terrance L.

2011-01-01

This paper presents a motion planning algorithm for Unmanned Surface Vehicles (USVs) to navigate safely in dynamic, cluttered environments. The proposed algorithm not only addresses Hazard Avoidance (HA) for stationary and moving hazards but also applies the International Regulations for Preventing Collisions at Sea (known as COLREGs). The COLREG rules specify, for example, which vessel is responsible for giving way to the other and to which side of the "stand-on" vessel to maneuver. The three primary COLREG rules were considered in this paper: crossing, overtaking, and head-on situations. For USVs to be safely deployed in environments with other traffic boats, it is imperative that the USV's navigation algorithm obey COLREGs. Note also that if other boats disregard their responsibility under COLREGs, the USV will still apply its HA algorithms to avoid a collision. The proposed approach is based on Velocity Obstacles, which generates a cone-shaped obstacle in the velocity space. Because Velocity Obstacles also specify which side of the obstacle the vehicle will pass during the avoidance maneuver, COLREGs are encoded in the velocity space in a natural way. The algorithm is demonstrated via both simulation and on-water tests.

Sensorimotor Model of Obstacle Avoidance in Echolocating Bats

PubMed Central

Vanderelst, Dieter; Holderied, Marc W.; Peremans, Herbert

2015-01-01

Bat echolocation is an ability consisting of many subtasks such as navigation, prey detection and object recognition. Understanding the echolocation capabilities of bats comes down to isolating the minimal set of acoustic cues needed to complete each task. For some tasks, the minimal cues have already been identified. However, while a number of possible cues have been suggested, little is known about the minimal cues supporting obstacle avoidance in echolocating bats. In this paper, we propose that the Interaural Intensity Difference (IID) and travel time of the first millisecond of the echo train are sufficient cues for obstacle avoidance. We describe a simple control algorithm based on the use of these cues in combination with alternating ear positions modeled after the constant frequency bat Rhinolophus rouxii. Using spatial simulations (2D and 3D), we show that simple phonotaxis can steer a bat clear from obstacles without performing a reconstruction of the 3D layout of the scene. As such, this paper presents the first computationally explicit explanation for obstacle avoidance validated in complex simulated environments. Based on additional simulations modelling the FM bat Phyllostomus discolor, we conjecture that the proposed cues can be exploited by constant frequency (CF) bats and frequency modulated (FM) bats alike. We hypothesize that using a low level yet robust cue for obstacle avoidance allows bats to comply with the hard real-time constraints of this basic behaviour. PMID:26502063

Issues in the Development and Evaluation of Cross-Cultural Training in a Business Setting.

ERIC Educational Resources Information Center

Broadbooks, Wendy J.

Issues in the development and evaluation of cross-cultural training in a business setting were investigated. Cross-cultural training and cross-cultural evaluation were defined as training and evaluation of training that involve the interaction of participants from two or more different countries. Two evaluations of a management development-type…

Cross-Cultural Training in Motivational Interviewing

ERIC Educational Resources Information Center

Miller, William R.; Hendrickson, Stacey M. L.; Venner, Kamilla; Bisono, Ani; Daugherty, Mikyta; Yahne, Carolina E.

2008-01-01

This study evaluated the cross-cultural transportability of motivational interviewing (MI), an evidence-based addiction treatment method. Free clinical training in MI was offered in separate targeted workshops for 86 African American, Native American, and Spanish-speaking addiction treatment providers. Audiotaped pre- and posttraining clinical…

Using virtual reality to train children in safe street-crossing skills.

PubMed

Schwebel, David C; McClure, Leslie A

2010-02-01

Pedestrian injuries are among the leading causes of morbidity and mortality in middle childhood. One limitation to existing pedestrian safety interventions is that they do not provide children with repeated practice needed to develop the complex perceptual and cognitive skills required for safe street crossing. Virtual reality offers training through repeated unsupervised practice without risk, automated feedback on success of crossings, adjustment of traffic to match children's skill and a fun, appealing environment for training. To test the efficacy of virtual reality to train child pedestrians in safe street crossing. Birmingham, Alabama, USA. A randomised controlled trial is underway with an expected sample of four groups of 60 children aged 7-8 years (total N=240). One group receives training in an interactive, immersive virtual pedestrian environment. A second receives pedestrian safety training via widely used video and computer strategies. The third group receives what is judged to be the most efficacious treatment currently available, individualised behavioural training at streetside locations. The fourth group serves as a no-contact control group. All participants are exposed to a range of field and laboratory-based measures of pedestrian skill during baseline and post-intervention visits, as well as during a 6-month follow-up assessment. Primary analyses will be conducted through linear mixed models testing change over time in the four intervention groups. Three pedestrian safety measures will serve as primary outcomes: temporal gap before initiating crossing, temporal gap remaining after crossing and attention to traffic while waiting to cross.

[Obstacles perceived by nurses for evidence-based practice: a qualitative study].

PubMed

Sánchez-García, Inmaculada; López-Medina, Isabel M; Pancorbo-Hidalgo, Pedro L

2013-01-01

To examine the obstacles perceived by nurses to implement an evidence-based clinical practice. A qualitative study through semi-structured interviews conducted in 2010-2011 including 11 nurses purposively selected from public hospitals and community centres in Jaén and Córdoba (Spain). A content analysis was performed, using Miles and Huberman as a reference and comprising the following steps: data reduction, data presentation, and data conclusion/verification. Data saturation was reached in these categories (obstacles). The obstacles perceived by nurses to introduce an evidence-based clinical practice (EBCP) were grouped into 3 major categories: obstacles related with professionals (routine-based practice, unwilling and stagnant attitudes, and lack of training in EBCP), obstacles related to the social context (reluctance from other professionals and from patients or families), and obstacles related to the organization (obsolete cultures that do not promote innovation in nursing care). This study highlights the persistence of various factors that hinder the use of research findings in clinical practice. The results underline the need to change the culture of healthcare organizations, to motivate professionals, and to break some of the resistance attitudes that hinder the implementation of evidence-based practice. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Cross-Cultural Psychiatric Residency Training: The Oregon Experience

ERIC Educational Resources Information Center

Boehnlein, James K.; Leung, Paul K.; Kinzie, John David

2008-01-01

Objective: The purpose of this article is to describe the goals and structure of cross-cultural psychiatric training at Oregon Health and Science University (OHSU). This training in core knowledge, skills, and attitudes of cultural psychiatry over the past three decades has included medical students, residents, and fellows, along with allied…

Student Workers: Cross Training in the Academic Environment

ERIC Educational Resources Information Center

Draper, Lani Hall; Oswald, Tina A.; Renfro, Margie

2007-01-01

Libraries rely heavily on student workers for the day-to-day running of the library. Stephen F. Austin State University in Nacogdoches, Texas is no different. We report on Steen Library's training efforts to staff several public service points as well as keep materials on the shelves by cross-training student employees.

Research productivity among faculty members at medical and health schools in Saudi Arabia. Prevalence, obstacles, and associated factors.

PubMed

Alghanim, Saad A; Alhamali, Rashid M

2011-12-01

To identify the prevalence, factors and obstacles affecting research productivity among academic staff at medical and health colleges in the Kingdom of Saudi Arabia. This cross-sectional survey employed self-administered questionnaires to collect data on faculty members' profile, research activities, and obstacles impeding research productivity. The questionnaires were distributed randomly to 500 faculty members, of which 389 (77.8%) completed the questionnaire at 10 medical and health colleges during January to April 2011. The data were analyzed and presented in a descriptive fashion. Only 150 (38.6%) respondents reported published work in the past 2 years. Of these, 80% indicated sole-authors research and around a quarter (26%) reported co-authors work. Males and young faculty members were more likely to publish research than their counterparts. Faculty members who reported involvement in administrative activities were less likely to publish. Those who reported supervising postgraduate students or had attained training on research methods were more likely to produce research. Respondents perceived that lack of time, lack of research assistants, lack of funds for research, and being busy with teaching load were the most cited obstacles impeding research productivity. Understanding factors and barriers impeding research productivity is a prerequisite for interventions that are directed to promote health services research among faculty members in medical schools.

Application of Optical Flow Sensors for Dead Reckoning, Heading Reference, Obstacle Detection, and Obstacle Avoidance

DTIC Science & Technology

2015-09-01

OPTICAL FLOW SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE by Tarek M. Nejah September 2015...SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE 5. FUNDING NUMBERS 6. AUTHOR(S) Nejah, Tarek M. 7...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) A novel approach for dead reckoning, heading reference, obstacle detection, and obstacle

Fables, Fancies and Failures in Cross-Cultural Training.

ERIC Educational Resources Information Center

Downs, James F.

1969-01-01

Several different approaches have been taken to cross-cultural training in Peace Corps Training programs. Three of these might be referred to as the intellectual model (consisting of lectures on the host country culture), the area simulation model (placing the trainees in a surrounding which in some way resembles the country in which they will be…

How do children learn to cross the street? The process of pedestrian safety training

PubMed Central

Schwebel, David C.; Shen, Jiabin; McClure, Leslie A.

2016-01-01

Objective Pedestrian injuries are a leading cause of child death, and may be reduced by training children to cross streets more safely. Such training is most effective when children receive repeated practice at the complex cognitive-perceptual task of judging moving traffic and selecting safe crossing gaps, but there is limited data on how much practice is required for children to reach adult levels of functioning. Using existing data, we examined how children’s pedestrian skill changed over the course of six pedestrian safety training sessions, each comprised of 45 crossings within a virtual pedestrian environment. Methods As part of a randomized controlled trial on pedestrian safety training, 59 children ages 7-8 crossed the street within a semi-immersive virtual pedestrian environment 270 times over a 3-week period (6 sessions of 45 crossings each). Feedback was provided after each crossing, and traffic speed and density was advanced as children’s skill improved. Post-intervention pedestrian behavior was assessed a week later in the virtual environment and compared to adult behavior with identical traffic patterns. Results Over the course of training, children entered traffic gaps more quickly and chose tighter gaps to cross within; their crossing efficiency appeared to increase. By the end of training, some aspects of children’s pedestrian behavior was comparable to adult behavior but other aspects were not, indicating the training was worthwhile but insufficient for most children to achieve adult levels of functioning. Conclusions Repeated practice in a simulated pedestrian environment helps children learn aspects of safe and efficient pedestrian behavior. Six twice-weekly training sessions of 45 crossings each were insufficient for children to reach adult pedestrian functioning, however, and future research should continue to study the trajectory and quantity of child pedestrian safety training needed for children to become competent pedestrians. PMID

Neural Network Compensation for Frequency Cross-Talk in Laser Interferometry

NASA Astrophysics Data System (ADS)

Lee, Wooram; Heo, Gunhaeng; You, Kwanho

The heterodyne laser interferometer acts as an ultra-precise measurement apparatus in semiconductor manufacture. However the periodical nonlinearity property caused from frequency cross-talk is an obstacle to improve the high measurement accuracy in nanometer scale. In order to minimize the nonlinearity error of the heterodyne interferometer, we propose a frequency cross-talk compensation algorithm using an artificial intelligence method. The feedforward neural network trained by back-propagation compensates the nonlinearity error and regulates to minimize the difference with the reference signal. With some experimental results, the improved accuracy is proved through comparison with the position value from a capacitive displacement sensor.

Lasting effects of short-term training on preschoolers' street-crossing behavior.

PubMed

Albert, Rachel R; Dolgin, Kim G

2010-03-01

Can short-term training improve preschoolers' knowledge of road-crossing concepts as well as behavior in a real traffic situation? Forty children, aged four to five years, were assigned to one of four conditions (game, story, song, and control). Each condition participated in four 15-min classroom-based lessons over four weeks. Two assessments measuring knowledge of street-crossing concepts and one assessment measuring behavior on a real street were used to evaluate performance at baseline and one week and six months post-training. Children in all three experimental conditions showed a significant improvement over the control on the two conceptual assessments. Only children in the game condition significantly improved their behavior on the street-crossing assessment. Furthermore, children in all three experimental conditions retained the same levels of improvement at the six-month follow-up. These results demonstrate that one hour of training can create lasting improvements on preschool children's conceptual knowledge of traffic safety and road-crossing behavior on a real street. Copyright 2009 Elsevier Ltd. All rights reserved.

Dynamic Obstacle Avoidance for Unmanned Underwater Vehicles Based on an Improved Velocity Obstacle Method

PubMed Central

Zhang, Wei; Wei, Shilin; Teng, Yanbin; Zhang, Jianku; Wang, Xiufang; Yan, Zheping

2017-01-01

In view of a dynamic obstacle environment with motion uncertainty, we present a dynamic collision avoidance method based on the collision risk assessment and improved velocity obstacle method. First, through the fusion optimization of forward-looking sonar data, the redundancy of the data is reduced and the position, size and velocity information of the obstacles are obtained, which can provide an accurate decision-making basis for next-step collision avoidance. Second, according to minimum meeting time and the minimum distance between the obstacle and unmanned underwater vehicle (UUV), this paper establishes the collision risk assessment model, and screens key obstacles to avoid collision. Finally, the optimization objective function is established based on the improved velocity obstacle method, and a UUV motion characteristic is used to calculate the reachable velocity sets. The optimal collision speed of UUV is searched in velocity space. The corresponding heading and speed commands are calculated, and outputted to the motion control module. The above is the complete dynamic obstacle avoidance process. The simulation results show that the proposed method can obtain a better collision avoidance effect in the dynamic environment, and has good adaptability to the unknown dynamic environment. PMID:29186878

Study protocol for improving asthma outcomes through cross-cultural communication training for physicians: a randomized trial of physician training.

PubMed

Patel, Minal R; Thomas, Lara J; Hafeez, Kausar; Shankin, Matthew; Wilkin, Margaret; Brown, Randall W

2014-06-16

Massive resources are expended every year on cross-cultural communication training for physicians. Such training is a focus of continuing medical education nationwide and is part of the curriculum of virtually every medical school in America. There is a pressing need for evidence regarding the effects on patients of cross-cultural communication training for physicians. There is a need to understand the added benefit of such training compared to more general communication. We know of no rigorous study that has assessed whether cross-cultural communication training for physicians results in better health outcomes for their patients. The current study aims to answer this question by enhancing the Physician Asthma Care Education (PACE) program to cross cultural communication (PACE Plus), and comparing the effect of the enhanced program to PACE on the health outcomes of African American and Latino/Hispanic children with asthma. A three-arm randomized control trial is used to compare PACE Plus, PACE, and usual care. Both PACE and PACE Plus are delivered in two, two-hour sessions over a period of two weeks to 5-10 primary care physicians who treat African American and Latino/Hispanic children with asthma. One hundred twelve physicians and 1060 of their pediatric patients were recruited who self-identify as African American or Latino/Hispanic and experience persistent asthma. Physicians were randomized into receiving either the PACE Plus or PACE intervention or into the control group. The comparative effectiveness of PACE and PACE Plus on clinician's therapeutic and communication practices with the family/patient, children's urgent care use for asthma, asthma control, and quality of life, and parent/caretaker satisfaction with physician performance will be assessed. Data are collected via telephone survey and medical record review at baseline, 9 months following the intervention, and 21 months following the intervention. This study aims to reduce disparities in asthma

Cross-education after high-frequency versus low-frequency volume-matched handgrip training.

PubMed

Boyes, Natasha G; Yee, Peter; Lanovaz, Joel L; Farthing, Jonathan P

2017-10-01

Cross-education training programs cause interlimb asymmetry of strength and hypertrophy. We examined the cross-education effects from a high-frequency (HF) versus a low-frequency (LF) volume-matched handgrip training program on interlimb asymmetry. Right-handed participants completed either HF (n = 10; 2 × 6 repetitions 10 times per week) or LF (n = 9; 5 × 8 repetitions 3 times per week) training. Testing occurred twice before and once after 4 weeks of right-handed isometric handgrip training totaling 120 weekly repetitions. Measures were maximal isometric handgrip and wrist flexion torque, muscle thickness, and muscle activation (electromyography; EMG). Grip strength was greater in both limbs posttraining, pooled across groups (P < 0.001). Trained limb muscle thickness increased in both groups (P < 0.05; untrained, P = 0.897). EMG and wrist flexion torque did not change (all P > 0.103). Both LF and HF induced cross-education of grip strength to the untrained limb, but HF did not reduce asymmetry. These findings have implications for injury rehabilitation. Muscle Nerve 56: 689-695, 2017. © 2017 Wiley Periodicals, Inc.

The Value of Removing Daily Obstacles via Everyday Problem-Solving Theory: Developing an Applied Novel Procedure to Increase Self-Efficacy for Exercise

PubMed Central

Artistico, Daniele; Pinto, Angela Marinilli; Douek, Jill; Black, Justin; Pezzuti, Lina

2012-01-01

The objective of the study was to develop a novel procedure to increase self-efficacy for exercise. Gains in one’s ability to resolve day-to-day obstacles for entering an exercise routine were expected to cause an increase in self-efficacy for exercise. Fifty-five sedentary participants (did not exercise regularly for at least 4 months prior to the study) who expressed an intention to exercise in the near future were selected for the study. Participants were randomly assigned to one of three conditions: (1) an Experimental Group in which they received a problem-solving training session to learn new strategies for solving day-to-day obstacles that interfere with exercise, (2) a Control Group with Problem-Solving Training which received a problem-solving training session focused on a typical day-to-day problem unrelated to exercise, or (3) a Control Group which did not receive any problem-solving training. Assessment of obstacles to exercise and perceived self-efficacy for exercise were conducted at baseline; perceived self-efficacy for exercise was reassessed post-intervention (1 week later). No differences in perceived challenges posed by obstacles to exercise or self-efficacy for exercise were observed across groups at baseline. The Experimental Group reported greater improvement in self-efficacy for exercise compared to the Control Group with Training and the Control Group. Results of this study suggest that a novel procedure that focuses on removing obstacles to intended planned fitness activities is effective in increasing self-efficacy to engage in exercise among sedentary adults. Implications of these findings for use in applied settings and treatment studies are discussed. PMID:23372560

The Value of Removing Daily Obstacles via Everyday Problem-Solving Theory: Developing an Applied Novel Procedure to Increase Self-Efficacy for Exercise.

PubMed

Artistico, Daniele; Pinto, Angela Marinilli; Douek, Jill; Black, Justin; Pezzuti, Lina

2013-01-01

The objective of the study was to develop a novel procedure to increase self-efficacy for exercise. Gains in one's ability to resolve day-to-day obstacles for entering an exercise routine were expected to cause an increase in self-efficacy for exercise. Fifty-five sedentary participants (did not exercise regularly for at least 4 months prior to the study) who expressed an intention to exercise in the near future were selected for the study. Participants were randomly assigned to one of three conditions: (1) an Experimental Group in which they received a problem-solving training session to learn new strategies for solving day-to-day obstacles that interfere with exercise, (2) a Control Group with Problem-Solving Training which received a problem-solving training session focused on a typical day-to-day problem unrelated to exercise, or (3) a Control Group which did not receive any problem-solving training. Assessment of obstacles to exercise and perceived self-efficacy for exercise were conducted at baseline; perceived self-efficacy for exercise was reassessed post-intervention (1 week later). No differences in perceived challenges posed by obstacles to exercise or self-efficacy for exercise were observed across groups at baseline. The Experimental Group reported greater improvement in self-efficacy for exercise compared to the Control Group with Training and the Control Group. Results of this study suggest that a novel procedure that focuses on removing obstacles to intended planned fitness activities is effective in increasing self-efficacy to engage in exercise among sedentary adults. Implications of these findings for use in applied settings and treatment studies are discussed.

Assessing the ground vibrations produced by a heavy vehicle traversing a traffic obstacle.

PubMed

Ducarne, Loïc; Ainalis, Daniel; Kouroussis, Georges

2018-01-15

Despite advancements in alternative transport networks, road transport remains the dominant mode in many modern and developing countries. The ground-borne motions produced by the passage of a heavy vehicle over a geometric obstacle (e.g. speed hump, train tracks) pose a fundamental problem in transport annoyance in urban areas. In order to predict the ground vibrations generated by the passage of a heavy vehicle over a geometric obstacle, a two-step numerical model is developed. The first step involves simulating the dynamic loads generated by the heavy vehicle using a multibody approach, which includes the tyre-obstacle-ground interaction. The second step involves the simulation of the ground wave propagation using a three dimensional finite element model. The simulation is able to be decoupled due to the large difference in stiffness between the vehicle's tyres and the road. First, the two-step model is validated using an experimental case study available in the literature. A sensitivity analysis is then presented, examining the influence of various factors on the generated ground vibrations. Factors investigated include obstacle shape, obstacle dimensions, vehicle speed, and tyre stiffness. The developed model can be used as a tool in the early planning stages to predict the ground vibrations generated by the passage of a heavy vehicle over an obstacle in urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Cross-education of wrist extensor strength is not influenced by non-dominant training in right-handers.

PubMed

Coombs, Timothy A; Frazer, Ashlyn K; Horvath, Deanna M; Pearce, Alan J; Howatson, Glyn; Kidgell, Dawson J

2016-09-01

Cross-education of strength has been proposed to be greater when completed by the dominant limb in right handed humans. We investigated whether the direction of cross-education of strength and corticospinal plasticity are different following right or left limb strength training in right-handed participants. Changes in strength, muscle thickness and indices of corticospinal plasticity were analyzed in 23 adults who were exposed to 3-weeks of either right-hand strength training (RHT) or left-hand strength training (LHT). Maximum voluntary wrist extensor strength in both the trained and untrained limb increased, irrespective of which limb was trained, with TMS revealing reduced corticospinal inhibition. Cross-education of strength was not limited by which limb was trained and reduced corticospinal inhibition was not just confined to the trained limb. Critically, from a behavioral perspective, the magnitude of cross-education was not limited by which limb was trained.

Are Injuries More Common With CrossFit Training Than Other Forms of Exercise?

PubMed

Klimek, Chelsey; Ashbeck, Christopher; Brook, Alexander J; Durall, Chris

2018-05-22

Clinical Scenario: CrossFit is a form of exercise that incorporates rapid and successive high-intensity ballistic movements. As CrossFit is an increasingly popular fitness option, it is important to determine how rates of injury compare to more traditional forms of exercise. This review was conducted to ascertain the incidence of injury with CrossFit relative to other forms of exercise. Focused Clinical Question: Are injuries more common with CrossFit training than other forms of exercise? Summary of Key Findings: (1) The literature was searched for studies that compared injury rates among individuals who participated in CrossFit fitness programs to participants in other exercise programs. (2) The search initially yielded >100 results, which were narrowed down to 3 level 2b retrospective cohort studies that were deemed to have met inclusion/exclusion criteria. (3) In all 3 reviewed studies, the reported incidences of injuries associated with CrossFit training programs were comparable or lower than rates of injury in Olympic weightlifting, distance running, track and field, rugby, or gymnastics. Clinical Bottom Line: Current evidence suggests that the injury risk from CrossFit training is comparable to Olympic weightlifting, distance running, track and field, rugby, football, ice hockey, soccer, or gymnastics. Injuries to the shoulder(s) appear to be somewhat common with CrossFit. However, the certitude of these conclusions is questionable given the lack of randomization, control, or uniform training in the reviewed studies. Clinicians should be aware that injury is more prevalent in cases where supervision is not always available to athletes. This is more often the case for male participants who may not actively seek supervision during CrossFit exercise. Strength of Recommendation: Level 2b evidence from 3 retrospective cohort studies indicates that the risk of injury from participation in CrossFit is comparable to or lower than some common forms of exercise or

The Role of Cross-Cultural Absorptive Capacity in the Effectiveness of In-Country Cross-Cultural Training

ERIC Educational Resources Information Center

Tarique, Ibraiz; Caligiuri, Paula

2009-01-01

Based on the theory of absorptive capacity, this study examines the following question. In the context of cross-cultural training, can the amount of previously accumulated cultural knowledge affect the ability of a trainee to absorb further learning about a new culture, thus enhancing total knowledge and presumably cross-cultural adjustment?…

Portuguese primary school children's conceptions about digestion: identification of learning obstacles

NASA Astrophysics Data System (ADS)

Silva, Rui Graça; Lima, Nelson; Coquet, Eduarda; Clément, Pierre

2004-09-01

A cross-sectional study of Portuguese primary school pupils' conceptions on digestion and the digestive tract was carried out before and after teaching this topic. Pupils of the prior four school years (5/6 to 9/10 year old) drew what happens to a cookie inside their body. In some cases they also wrote a short text or were interviewed. To identify their level of graphic development, they produced a free-hand drawing. The main conceptual changes in explaining digestion were strongly linked to teaching. Children's previous conceptions were not epistemological obstacles to learning about digestion. The main obstacles were of didactical origin, as images of primary school books do not represent (i) the path of food from the intestine into the blood, (associated to the epistemological obstacle of the permeability of the gut wall); (ii) a clear continuous tract from stomach to anus, which causes a specific confusion at the intestine level.

Home-based interventions improve trained, but not novel, dual-task balance performance in older adults: A randomized controlled trial.

PubMed

Wongcharoen, Suleeporn; Sungkarat, Somporn; Munkhetvit, Peeraya; Lugade, Vipul; Silsupadol, Patima

2017-02-01

The purpose of this study was to compare the efficacy of four different home-based interventions on dual-task balance performance and to determine the generalizability of the four trainings to untrained tasks. Sixty older adults, aged 65 and older, were randomly assigned to one of four home-based interventions: single-task motor training, single-task cognitive training, dual-task motor-cognitive training, and dual-task cognitive-cognitive training. Participants received 60-min individualized training sessions, 3 times a week for 4 weeks. Prior to and following the training program, participants were asked to walk under two single-task conditions (i.e. narrow walking and obstacle crossing) and two dual-task conditions (i.e. a trained narrow walking while performing verbal fluency task and an untrained obstacle crossing while counting backward by 3s task). A nine-camera motion capture system was used to collect the trajectories of 32 reflective markers placed on bony landmarks of participants. Three-dimensional kinematics of the whole body center of mass and base of support were computed. Results from the extrapolated center of mass displacement indicated that motor-cognitive training was more effective than the single-task motor training to improve dual-task balance performance (p=0.04, ES=0.11). Interestingly, balance performance under both single-task and dual-task conditions can also be improved through a non-motor, single-task cognitive training program (p=0.01, ES=0.13, and p=0.01, ES=0.11, respectively). However, improved dual-task processing skills during training were not transferred to the novel dual task (p=0.15, ES=0.09). This is the first study demonstrating that home-based dual-task training can be effectively implemented to improve balance performance during gait in older adults. Copyright © 2016 Elsevier B.V. All rights reserved.

Cascading a systolic array and a feedforward neural network for navigation and obstacle avoidance using potential fields

NASA Technical Reports Server (NTRS)

Plumer, Edward S.

1991-01-01

A technique is developed for vehicle navigation and control in the presence of obstacles. A potential function was devised that peaks at the surface of obstacles and has its minimum at the proper vehicle destination. This function is computed using a systolic array and is guaranteed not to have local minima. A feedfoward neural network is then used to control the steering of the vehicle using local potential field information. In this case, the vehicle is a trailer truck backing up. Previous work has demonstrated the capability of a neural network to control steering of such a trailer truck backing to a loading platform, but without obstacles. Now, the neural network was able to learn to navigate a trailer truck around obstacles while backing toward its destination. The network is trained in an obstacle free space to follow the negative gradient of the field, after which the network is able to control and navigate the truck to its target destination in a space of obstacles which may be stationary or movable.

New Walkers with Down Syndrome Use Cautious but Effective Strategies for Crossing Obstacles

ERIC Educational Resources Information Center

Mulvey, Genna M.; Kubo, Masayoshi; Chang, Chia-Lin; Ulrich, Beverly D.

2011-01-01

Perception of affordances research in children with developmental disabilities has only examined well practiced skills. Ten toddlers with Down syndrome and 10 with typical development walked across a GAITRite mat, with and without an obstacle. We coded the toddlers' behaviors after 1 and 3 months of walking experience when they encountered the…

Chemical Dependency and Violence: Working with Dually Affected Families. A Cross-Training Program Manual for Counselors and Advocates.

ERIC Educational Resources Information Center

Wright, Janet M.

This manual is designed as a cross-training program guide for counselors working in the fields of woman abuse and chemical dependency. (A cross-training program is a system for one (or more) agency personnel to train each other in their respective areas of expertise.) Chapter 1 discusses the rationale and goals of a cross-training program; issues…

Canadian residents' perceptions of cross-cultural care training in graduate medical school.

PubMed

Singh, Barinder; Banwell, Emma; Groll, Dianne

2017-12-01

The Royal College of Physicians and Surgeons of Canada specifies both respect for diversity as a requirement of professionalism and culturally sensitive provision of medical care. The purpose of the present study was to evaluate the perception of preparedness and attitudes of medical residents to deliver cross-cultural care. The Cross Cultural Care Survey was sent via e-mail to all Faculty of Medicine residents (approx. 450) in an academic health sciences centre. Comparisons were made between psychiatry residents, family medicine residents, and other residency groups with respect to training, preparedness, and skillfulness in delivering cross-cultural care. Seventy-three (16%) residents responded to the survey. Residents in psychiatry and family medicine reported significantly more training and formal evaluation regarding cross-cultural care than residents in other programs. However, there were no significant differences in self-reported preparedness and skillfulness. Residents in family medicine were more likely to report needing more practical experience working with diverse groups. Psychiatry residents were less likely to report inadequate cross-cultural training. While most residents reported feeling skillful and prepared to work with culturally diverse groups, they report receiving little additional instruction or formal evaluation on this topic, particularly in programs other than psychiatry and family medicine.

Canadian residents’ perceptions of cross-cultural care training in graduate medical school

PubMed Central

Singh, Barinder; Banwell, Emma; Groll, Dianne

2017-01-01

Background The Royal College of Physicians and Surgeons of Canada specifies both respect for diversity as a requirement of professionalism and culturally sensitive provision of medical care. The purpose of the present study was to evaluate the perception of preparedness and attitudes of medical residents to deliver cross-cultural care. Methods The Cross Cultural Care Survey was sent via e-mail to all Faculty of Medicine residents (approx. 450) in an academic health sciences centre. Comparisons were made between psychiatry residents, family medicine residents, and other residency groups with respect to training, preparedness, and skillfulness in delivering cross-cultural care. Results Seventy-three (16%) residents responded to the survey. Residents in psychiatry and family medicine reported significantly more training and formal evaluation regarding cross-cultural care than residents in other programs. However, there were no significant differences in self-reported preparedness and skillfulness. Residents in family medicine were more likely to report needing more practical experience working with diverse groups. Psychiatry residents were less likely to report inadequate cross-cultural training. Conclusion While most residents reported feeling skillful and prepared to work with culturally diverse groups, they report receiving little additional instruction or formal evaluation on this topic, particularly in programs other than psychiatry and family medicine. PMID:29354194

Vision Based Obstacle Detection in Uav Imaging

NASA Astrophysics Data System (ADS)

Badrloo, S.; Varshosaz, M.

2017-08-01

Detecting and preventing incidence with obstacles is crucial in UAV navigation and control. Most of the common obstacle detection techniques are currently sensor-based. Small UAVs are not able to carry obstacle detection sensors such as radar; therefore, vision-based methods are considered, which can be divided into stereo-based and mono-based techniques. Mono-based methods are classified into two groups: Foreground-background separation, and brain-inspired methods. Brain-inspired methods are highly efficient in obstacle detection; hence, this research aims to detect obstacles using brain-inspired techniques, which try to enlarge the obstacle by approaching it. A recent research in this field, has concentrated on matching the SIFT points along with, SIFT size-ratio factor and area-ratio of convex hulls in two consecutive frames to detect obstacles. This method is not able to distinguish between near and far obstacles or the obstacles in complex environment, and is sensitive to wrong matched points. In order to solve the above mentioned problems, this research calculates the dist-ratio of matched points. Then, each and every point is investigated for Distinguishing between far and close obstacles. The results demonstrated the high efficiency of the proposed method in complex environments.

Previous International Experience, Cross-Cultural Training, and Expatriates' Cross-Cultural Adjustment: Effects of Cultural Intelligence and Goal Orientation

ERIC Educational Resources Information Center

Koo Moon, Hyoung; Kwon Choi, Byoung; Shik Jung, Jae

2012-01-01

Although various antecedents of expatriates' cross-cultural adjustment have been addressed, previous international experience, predeparture cross-cultural training, and cultural intelligence (CQ) have been most frequently examined. However, there are few attempts that explore the effects of these antecedents simultaneously or consider the possible…

Peace Corps Stateside Teacher Training for Volunteers in Liberia. Volume V: Cross-Cultural Training and Support Services. Final Report.

ERIC Educational Resources Information Center

PSI Associates, Inc., Washington, DC.

The cross-cultural training module and support services for Peace Corps volunteers en route to Liberia make trainees more aware of and sensitive to cultural differences in human behavior and human interaction. In this part of the Peace Corps Stateside Teacher Training Model, the approach to training is both generic and specific, and both native…

Do characteristics of a stationary obstacle lead to adjustments in obstacle stepping strategies?

PubMed

Worden, Timothy A; De Jong, Audrey F; Vallis, Lori Ann

2016-01-01

Navigating cluttered and complex environments increases the risk of falling. To decrease this risk, it is important to understand the influence of obstacle visual cues on stepping parameters, however the specific obstacle characteristics that have the greatest influence on avoidance strategies is still under debate. The purpose of the current work is to provide further insight on the relationship between obstacle appearance in the environment and modulation of stepping parameters. Healthy young adults (N=8) first stepped over an obstacle with one visible top edge ("floating"; 8 trials) followed by trials where experimenters randomly altered the location of a ground reference object to one of 7 different positions (8 trials per location), which ranged from 6cm in front of, directly under, or up to 6cm behind the floating obstacle (at 2cm intervals). Mean take-off and landing distance as well as minimum foot clearance values were unchanged across different positions of the ground reference object; a consistent stepping trajectory was observed for all experimental conditions. Contrary to our hypotheses, results of this study indicate that ground based visual cues are not essential for the planning of stepping and clearance strategies. The simultaneous presentation of both floating and ground based objects may have provided critical information that lead to the adoption of a consistent strategy for clearing the top edge of the obstacle. The invariant foot placement observed here may be an appropriate stepping strategy for young adults, however this may not be the case across the lifespan or in special populations. Copyright © 2015 Elsevier B.V. All rights reserved.

Cross-Cultural Training of Expatriate Faculty Teaching in International Branch Campuses

ERIC Educational Resources Information Center

Jauregui, Martin

2013-01-01

This study investigates the intersection between academics and culture in international branch campus using Stier's (2006) "cross-cultural characteristics and competencies." The purpose of this study was to examine the type of cross-cultural training being used by the international branch campuses in Qatar's Education City, in particular…

Training addiction professionals in empirically supported treatments: perspectives from the treatment community.

PubMed

Hartzler, Bryan; Rabun, Carl

2014-01-01

Large-scale dissemination efforts seek to expand opportunities for the addiction treatment community to receive training in empirically supported treatments (ESTs). Prospective consumers of such training are valuable sources of input about content of interest, preferences for how training events are structured, and obstacles that deter receipt of training. In this mixed-method study, data were collected in 64 semistructured individual interviews with personnel during site visits to 16 community opioid treatment programs (OTPs). At each OTP, interviews were completed with the executive director, a clinical supervisor, and 2 direct-service clinicians. Topical interests were analyzed qualitatively in a cultural domain analysis. Likert ratings of training event preferences were analyzed via generalized linear mixed models (GLMMs), and unstructured interviewee comments were analyzed via narrative analysis. Obstacles to training receipt were analyzed qualitatively with both content coding and narrative analysis. Based on topics of reported interest, cultural domain analysis suggests as ESTs of note: Multidimensional Family Therapy, Motivational Enhancement Therapy, Relapse Prevention Therapy, "Seeking Safety," and broad addiction-focused pharmacotherapy. Regarding training event preferences, GLMMs and narrative analysis revealed clear preferences for time-distributed trainings and use of participatory activities (e.g., trainer demonstrations, role plays, small group exercises). Content coding identified cost as the primary obstacle to receipt of EST trainings, followed by lack of time, logistical challenges, and disinterest, and narrative analysis elaborated on contextual issues underlying these obstacles. As primary consumers of EST technologies, the treatment community has valuable input to offer. Dissemination efforts may be enhanced by greater consideration of their preferences for training content and event structure, as well as practical obstacles that challenge

Women's orgasm obstacles: A qualitative study.

PubMed

Nekoolaltak, Maryam; Keshavarz, Zohreh; Simbar, Masoumeh; Nazari, Ali Mohammad; Baghestani, Ahmad Reza

2017-08-01

Woman's orgasm plays a vital role in sexual compatibility and marital satisfaction. Orgasm in women is a learnable phenomenon that is influenced by several factors. The aim of this study is exploring obstacles to orgasm in Iranian married women. This qualitative study with directed content analysis approach was conducted in 2015-2016, on 20 Iranian married women who were individually interviewed at two medical clinics in Tehran, Iran. Orgasm obstacles were explored in one category, 4 subcategories, and 25 codes. The main category was "Multidimensionality of women's orgasm obstacles". Subcategories and some codes included: Physical obstacles (wife's or husband's boredom, vaginal infection, insufficient vaginal lubrication), psychological obstacles (lack of sexual knowledge, shame, lack of concentration on sex due to household and children problems), relational obstacles (husband's hurry, having a dispute and annoyance with spouse) and contextual obstacles (Irregular sleep hours, lack of privacy and inability to separate children's bedroom from their parents, lack of peace at home). For prevention or treatment of female orgasm disorders, attention to physical factors is not enough. Obtaining a comprehensive history about physical, psychological, relational and contextual dimensions of woman's life is necessary.

Effects of cross-training on markers of insulin resistance/hyperinsulinemia.

PubMed

Wallace, M B; Mills, B D; Browning, C L

1997-09-01

This study examined, through a randomized controlled trial, the effects of cross-training (combined resistance and endurance exercise) on markers of insulin resistance, (e.g., dyslipidemia, intra-abdominal obesity, hyperinsulinemia, and hypertension), body composition, and performance in hyperinsulinemic individuals. Sedentary adult males characterized as hyperinsulinemic (fasting insulin > 2 OuU.mL-1), randomly assigned to two groups (N = 8 each), completed 14 wk of training at 3 d.wk-1. An endurance-only (E) group performed both continuous cycle exercise and walking (30 min each at 60-70% heart rate reserve). A cross-training (C) group performed both endurance and resistance exercise (8 exercises, 4 sets/exercise, 8-12 repetitions/set) in a single session. Both E and C groups demonstrated similar increases in VO2max (25% and 27%) while only C demonstrated an increase in 1 RM bench press (19%) and leg press (25%). The changes induced by C training were significantly greater than those from E training alone in percent fat (6.9 +/- 1.3 vs 1.4 +/- 1.4), insulin concentration (8.5 +/- 2.7 vs 3.0 +/- 1.3 uU.mL-1), glucose levels (11.1 +/- 2.9 vs 5.9 +/- 2.6 mg.dL-1), HDL-C levels (5.1 +/- 1.3 vs 2.9 +/- 1.6 mg.dL-1), triglyceride concentration (43.8 +/- 13.6 mg.dL-1), and systolic blood pressure (14.6 +/- 5.5 vs 8.3 +/- 6.8 mm Hg). Results indicate that the addition of resistance training to an endurance training program will induce significantly greater differences in markers of insulin resistance and body composition in individuals with hyperinsulinemia than endurance training alone.

Professional Training of Future Teacher in Cross-Cultural Dialogue

ERIC Educational Resources Information Center

Semenog, Olena

2014-01-01

On the example of propaedeutic educational course "Introduction to Slavic Philology" features of future teachers' professional training of cross-cultural dialogue are considered. Among the main objectives of the course, attention is focused on native language and other languages admirer's tolerance education, students' skills formation…

A reciprocity formulation for the EM scattering by an obstacle within a large open cavity

NASA Technical Reports Server (NTRS)

Pathak, Prabhakar H.; Burkholder, Robert J.

1993-01-01

A formulation based on a generalized reciprocity theorem is developed for analyzing the external high frequency EM scattering by a complex obstacle inside a relatively arbitrary open-ended waveguide cavity when it is illuminated by an external source. This formulation is also extended to include EM fields whose time dependence may be nonperiodic. A significant advantage of this formulation is that it allows one to break up the analysis into two independent parts; one deals with the waveguide cavity shape alone and the other with the obstacle alone. The external scattered field produced by the obstacle (in the presence of the waveguide cavity structure) is given in terms of a generalized reciprocity integral over a surface S(T) corresponding to the interior waveguide cavity cross section located conveniently but sufficiently close to the obstacle. Furthermore, the fields coupled into the cavity from the source in the exterior region generally need to propagate only one-way via the open front end (which is directly illuminated) to the interior surface S(T) in this approach, and not back, in order to find the external field scattered by the obstacle.

A switching formation strategy for obstacle avoidance of a multi-robot system based on robot priority model.

PubMed

Dai, Yanyan; Kim, YoonGu; Wee, SungGil; Lee, DongHa; Lee, SukGyu

2015-05-01

This paper describes a switching formation strategy for multi-robots with velocity constraints to avoid and cross obstacles. In the strategy, a leader robot plans a safe path using the geometric obstacle avoidance control method (GOACM). By calculating new desired distances and bearing angles with the leader robot, the follower robots switch into a safe formation. With considering collision avoidance, a novel robot priority model, based on the desired distance and bearing angle between the leader and follower robots, is designed during the obstacle avoidance process. The adaptive tracking control algorithm guarantees that the trajectory and velocity tracking errors converge to zero. To demonstrate the validity of the proposed methods, simulation and experiment results present that multi-robots effectively form and switch formation avoiding obstacles without collisions. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Obstacle-avoiding navigation system

DOEpatents

Borenstein, Johann; Koren, Yoram; Levine, Simon P.

1991-01-01

A system for guiding an autonomous or semi-autonomous vehicle through a field of operation having obstacles thereon to be avoided employs a memory for containing data which defines an array of grid cells which correspond to respective subfields in the field of operation of the vehicle. Each grid cell in the memory contains a value which is indicative of the likelihood, or probability, that an obstacle is present in the respectively associated subfield. The values in the grid cells are incremented individually in response to each scan of the subfields, and precomputation and use of a look-up table avoids complex trigonometric functions. A further array of grid cells is fixed with respect to the vehicle form a conceptual active window which overlies the incremented grid cells. Thus, when the cells in the active window overly grid cell having values which are indicative of the presence of obstacles, the value therein is used as a multiplier of the precomputed vectorial values. The resulting plurality of vectorial values are summed vectorially in one embodiment of the invention to produce a virtual composite repulsive vector which is then summed vectorially with a target-directed vector for producing a resultant vector for guiding the vehicle. In an alternative embodiment, a plurality of vectors surrounding the vehicle are computed, each having a value corresponding to obstacle density. In such an embodiment, target location information is used to select between alternative directions of travel having low associated obstacle densities.

Effects of resistance training on running economy and cross-country performance.

PubMed

Barnes, Kyle R; Hopkins, Will G; McGuigan, Michael R; Northuis, Mark E; Kilding, Andrew E

2013-12-01

Heavy-resistance training and plyometric training offer distinct physiological and neuromuscular adaptations that could enhance running economy and, consequently, distance-running performance. To date, no studies have examined the effect of combining the two modes of training on running economy or performance. Fifty collegiate male and female cross-country runners performed a 5-km time trial and a series of laboratory-based tests to determine aerobic, anthropometric, biomechanical, and neuromuscular characteristics. Thereafter, each athlete participated in a season of six to eight collegiate cross-country races for 13 wk. After the first 4 wk, athletes were randomly assigned to either heavy-resistance or plyometric plus heavy-resistance training. Five days after completing their final competition, runners repeated the same set of laboratory tests. We also estimated the effects of the intervention on competition performance throughout the season using athletes of other teams as controls. Heavy-resistance training produced small-moderate improvements in peak speed, running economy, and neuromuscular characteristics relative to plyometric resistance training, whereas changes in biomechanical measures favored plyometric resistance training. Men made less gains than women in most tests. Both treatments had possibly harmful effects on competition times in men (mean = 0.5%; 90% confidence interval = ±1.2%), but there may have been benefit for some individuals. Both treatments were likely beneficial for all women (-1.2%; ±1.3%), but heavy-resistance training was possibly better than plyometric resistance training. The changes in laboratory-based parameters related to distance-running performance were consistent with the changes in competition times for women but only partly for men. Our data indicate that women should include heavy-resistance training in their programs, but men should be cautious about using it in season until more research establishes whether certain

Negative obstacle detection by thermal signature

NASA Technical Reports Server (NTRS)

Matthies, Larry; Rankin, A.

2003-01-01

Detecting negative obstacles (ditches, potholes, and other depressions) is one of the most difficult problems in perception for autonomous, off-road navigation. Past work has largely relied on range imagery, because that is based on the geometry of the obstacle, is largely insensitive to illumination variables, and because there have not been other reliable alternatives. However, the visible aspect of negative obstacles shrinks rapidly with range, making them impossible to detect in time to avoid them at high speed. To relive this problem, we show that the interiors of negative obstacles generally remain warmer than the surrounding terrain throughout the night, making thermal signature a stable property for night-time negative obstacle detection. Experimental results to date have achieved detection distances 45% greater by using thermal signature than by using range data alone. Thermal signature is the first known observable with potential to reveal a deep negative obstacle without actually seeing far into it. Modeling solar illumination has potential to extend the usefulness of thermal signature through daylight hours.

Apparent motion perception in lower limb amputees with phantom sensations: "obstacle shunning" and "obstacle tolerance".

PubMed

Saetta, Gianluca; Grond, Ilva; Brugger, Peter; Lenggenhager, Bigna; Tsay, Anthony J; Giummarra, Melita J

2018-03-21

Phantom limbs are the phenomenal persistence of postural and sensorimotor features of an amputated limb. Although immaterial, their characteristics can be modulated by the presence of physical matter. For instance, the phantom may disappear when its phenomenal space is invaded by objects ("obstacle shunning"). Alternatively, "obstacle tolerance" occurs when the phantom is not limited by the law of impenetrability and co-exists with physical objects. Here we examined the link between this under-investigated aspect of phantom limbs and apparent motion perception. The illusion of apparent motion of human limbs involves the perception that a limb moves through or around an object, depending on the stimulus onset asynchrony (SOA) for the two images. Participants included 12 unilateral lower limb amputees matched for obstacle shunning (n = 6) and obstacle tolerance (n = 6) experiences, and 14 non-amputees. Using multilevel linear models, we replicated robust biases for short perceived trajectories for short SOA (moving through the object), and long trajectories (circumventing the object) for long SOAs in both groups. Importantly, however, amputees with obstacle shunning perceived leg stimuli to predominantly move through the object, whereas amputees with obstacle tolerance perceived leg stimuli to predominantly move around the object. That is, in people who experience obstacle shunning, apparent motion perception of lower limbs was not constrained to the laws of impenetrability (as the phantom disappears when invaded by objects), and legs can therefore move through physical objects. Amputees who experience obstacle tolerance, however, had stronger solidity constraints for lower limb apparent motion, perhaps because they must avoid co-location of the phantom with physical objects. Phantom limb experience does, therefore, appear to be modulated by intuitive physics, but not in the same way for everyone. This may have important implications for limb experience post

A comparison of surgery and family medicine residents' perceptions of cross-cultural care training.

PubMed

Chun, Maria B J; Jackson, David S; Lin, Susan Y; Park, Elyse R

2010-12-01

The need for physicians formally trained to deliver care to diverse patient populations has been widely advocated. Utilizing a validated tool, Weissman and Betancourt's Cross-Cultural Care Survey, the aim of this current study was to compare surgery and family medicine residents' perceptions of their preparedness and skillfulness to provide high quality cross-cultural care. Past research has documented differences between the two groups' reported impressions of importance and level of instruction received in cross-cultural care. Twenty surgery and 15 family medicine residents participated in the study. Significant differences were found between surgery and family medicine residents on most ratings of the amount of training they received in cross-cultural skills. Specifically, family medicine residents reported having received more training on: 1) determining how patients want to be addressed, 2) taking a social history, 3) assessing their understanding of the cause of illness, 4) negotiating their treatment plan, 5) assessing whether they are mistrustful of the health care system and÷or doctor, 6) identifying cultural customs, 7) identifying how patients make decisions within the family, and 8) delivering services through a medical interpreter. One unexpected finding was that surgery residents, who reported not receiving much formal cultural training, reported higher mean scores on perceived skillfulness (i.e. ability) than family medicine residents. The disconnect may be linked to the family medicine residents' training in cultural humility - more knowledge and understanding of cross-cultural care can paradoxically lead to perceptions of being less prepared or skillful in this area. Hawaii Medical Journal Copyright 2010.

Exploring performance obstacles of intensive care nurses.

PubMed

Gurses, Ayse P; Carayon, Pascale

2009-05-01

High nursing workload, poor patient safety, and poor nursing quality of working life (QWL) are major issues in intensive care units (ICUs). Characteristics of the ICU and performance obstacles may contribute to these issues. The goal of this study was to comprehensively identify the performance obstacles perceived by ICU nurses. We used a qualitative research design and conducted semi-structured interviews with 15 ICU nurses of a medical-surgical ICU. Based on this qualitative study and a previously reported quantitative study, we identified seven main types of performance obstacles experienced by ICU nurses. Obstacles related to the physical environment (e.g., noise, amount of space), family relations (e.g., distractions caused by family, lack of time to spend with family), and equipment (e.g., unavailability, misplacement) were the most frequently experienced performance obstacles. The qualitative interview data provided rich information regarding the factors contributing to the performance obstacles. Overall, ICU nurses experience a variety of performance obstacles in their work on a daily basis. Future research is needed to understand the impact of performance obstacles on nursing workload, nursing QWL, and quality and safety of care.

Obstacles to colorectal screening in general practice: a qualitative study of GPs and patients.

PubMed

Aubin-Auger, Isabelle; Mercier, Alain; Lebeau, Jean-Pierre; Baumann, Laurence; Peremans, Lieve; Van Royen, Paul

2011-12-01

The faecal occult blood test (FOBT) has proven efficiency at screening populations for an average risk of colorectal cancer. Mortality related to this cancer decreases by 15-18% among adults, 50-74 years old, tested every 2 years. A participation rate of at least 50% is desirable. This rate has not yet been reached in most French regions. To explore the obstacles to mass colorectal screening in France. In 2009, five focus groups were conducted in different areas to explore physicians' obstacles to FOBT screening. The patients' obstacles were assessed in semi-structured interviews. A purposive sampling had been carried out for both GPs and patients. The focus groups were coded using Nvivo 8(®) software by three researchers; the interviews manually coded by two researchers. GPs reported insufficient training and some doubted the relevance of screening. They expressed concern of having insufficient time for the test during a consultation, as well as practical and administrative obstacles. Some GPs experienced difficulty persuading patients who had no signs of colorectal disease. Obstacles for patients were mainly difficulties in doing screening themselves and a perception of health care that didn't match with screening. Information and organization were also important points to improve. The screening process was considered complex both by GPs and by patients. Numerous obstacles to colorectal screening, from both the physicians' and the patients' perspectives, were found. The major goal to improve mass screening may be to increase awareness and understanding of both physicians and patients regarding this process.

Dynamics of spiral waves rotating around an obstacle and the existence of a minimal obstacle

NASA Astrophysics Data System (ADS)

Gao, Xiang; Feng, Xia; Li, Teng-Chao; Qu, Shixian; Wang, Xingang; Zhang, Hong

2017-05-01

Pinning of vortices by obstacles plays an important role in various systems. In the heart, anatomical reentry is created when a vortex, also known as the spiral wave, is pinned to an anatomical obstacle, leading to a class of physiologically very important arrhythmias. Previous analyses of its dynamics and instability provide fine estimates in some special circumstances, such as large obstacles or weak excitabilities. Here, to expand theoretical analyses to all circumstances, we propose a general theory whose results quantitatively agree with direct numerical simulations. In particular, when obstacles are small and pinned spiral waves are destabilized, an accurate explanation of the instability in two-dimensional media is provided by the usage of a mapping rule and dimension reduction. The implications of our results are to better understand the mechanism of arrhythmia and thus improve its early prevention.

Obstacle Avoidance On Roadways Using Range Data

NASA Astrophysics Data System (ADS)

Dunlay, R. Terry; Morgenthaler, David G.

1987-02-01

This report describes range data based obstacle avoidance techniques developed for use on an autonomous road-following robot vehicle. The purpose of these techniques is to detect and locate obstacles present in a road environment for navigation of a robot vehicle equipped with an active laser-based range sensor. Techniques are presented for obstacle detection, obstacle location, and coordinate transformations needed in the construction of Scene Models (symbolic structures representing the 3-D obstacle boundaries used by the vehicle's Navigator for path planning). These techniques have been successfully tested on an outdoor robotic vehicle, the Autonomous Land Vehicle (ALV), at speeds up to 3.5 km/hour.

Team Training for Dynamic Cross-Functional Teams in Aviation: Behavioral, Cognitive, and Performance Outcomes.

PubMed

Littlepage, Glenn E; Hein, Michael B; Moffett, Richard G; Craig, Paul A; Georgiou, Andrea M

2016-12-01

This study evaluates the effectiveness of a training program designed to improve cross-functional coordination in airline operations. Teamwork across professional specializations is essential for safe and efficient airline operations, but aviation education primarily emphasizes positional knowledge and skill. Although crew resource management training is commonly used to provide some degree of teamwork training, it is generally focused on specific specializations, and little training is provided in coordination across specializations. The current study describes and evaluates a multifaceted training program designed to enhance teamwork and team performance of cross-functional teams within a simulated airline flight operations center. The training included a variety of components: orientation training, position-specific declarative knowledge training, position-specific procedural knowledge training, a series of high-fidelity team simulations, and a series of after-action reviews. Following training, participants demonstrated more effective teamwork, development of transactive memory, and more effective team performance. Multifaceted team training that incorporates positional training and team interaction in complex realistic situations and followed by after-action reviews can facilitate teamwork and team performance. Team training programs, such as the one described here, have potential to improve the training of aviation professionals. These techniques can be applied to other contexts where multidisciplinary teams and multiteam systems work to perform highly interdependent activities. © 2016, Human Factors and Ergonomics Society.

Exploring the Effects of Cultural Values and Beliefs on Cross-Cultural Training

ERIC Educational Resources Information Center

Yang, Baiyin; Wang, Yingchun; Drewry, Anne Wang

2006-01-01

This article seeks to develop a framework for assessing the impacts of cultural values and beliefs on cross-cultural training (CCT). It argues that culture affects CCT processes including the use of training methods, trainers' selection, and trainees' learning style. The article also reasons that the congruence between parent and host cultures…

Surface obstacles in pulsatile flow

NASA Astrophysics Data System (ADS)

Carr, Ian A.; Plesniak, Michael W.

2017-11-01

Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e., constant velocity, unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigate the wake of two canonical obstacles: a cube and a circular cylinder with an aspect ratio of unity. Our previous studies of a surface-mounted hemisphere in pulsatile flow are used as a baseline for these two new, more complex geometries. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings.

Aviation obstacle auto-extraction using remote sensing information

NASA Astrophysics Data System (ADS)

Zimmer, N.; Lugsch, W.; Ravenscroft, D.; Schiefele, J.

2008-10-01

An Obstacle, in the aviation context, may be any natural, man-made, fixed or movable object, permanent or temporary. Currently, the most common way to detect relevant aviation obstacles from an aircraft or helicopter for navigation purposes and collision avoidance is the use of merged infrared and synthetic information of obstacle data. Several algorithms have been established to utilize synthetic and infrared images to generate obstacle information. There might be a situation however where the system is error-prone and may not be able to consistently determine the current environment. This situation can be avoided when the system knows the true position of the obstacle. The quality characteristics of the obstacle data strongly depends on the quality of the source data such as maps and official publications. In some countries such as newly industrializing and developing countries, quality and quantity of obstacle information is not available. The aviation world has two specifications - RTCA DO-276A and ICAO ANNEX 15 Ch. 10 - which describe the requirements for aviation obstacles. It is essential to meet these requirements to be compliant with the specifications and to support systems based on these specifications, e.g. 3D obstacle warning systems where accurate coordinates based on WGS-84 is a necessity. Existing aerial and satellite or soon to exist high quality remote sensing data makes it feasible to think about automated aviation obstacle data origination. This paper will describe the feasibility to auto-extract aviation obstacles from remote sensing data considering limitations of image and extraction technologies. Quality parameters and possible resolution of auto-extracted obstacle data will be discussed and presented.

Virtual Reality: A Strategy for Training in Cross-Cultural Communication.

ERIC Educational Resources Information Center

Meyer, Catherine; Dunn-Roberts, Richard

1992-01-01

Defines virtual reality and explains terminology, theoretical concepts, and enabling technologies. Research and applications are described; limitations of current technology are considered; and future possibilities are discussed, including the use of virtual reality in training for cross-cultural communication. (22 references) (LRW)

Obstacles for Teachers to Integrate Technology with Instruction

ERIC Educational Resources Information Center

Alenezi, Abdullah

2017-01-01

This paper covers type one and two educational obstacles in using technology in the classrooms, and considering those obstacles tries to find the answer to the following overarching research question which can help to gauge some obstacles for the educational technology integration for elementary and high school education: What obstacles do…

Fast obstacle detection based on multi-sensor information fusion

NASA Astrophysics Data System (ADS)

Lu, Linli; Ying, Jie

2014-11-01

Obstacle detection is one of the key problems in areas such as driving assistance and mobile robot navigation, which cannot meet the actual demand by using a single sensor. A method is proposed to realize the real-time access to the information of the obstacle in front of the robot and calculating the real size of the obstacle area according to the mechanism of the triangle similarity in process of imaging by fusing datum from a camera and an ultrasonic sensor, which supports the local path planning decision. In the part of image analyzing, the obstacle detection region is limited according to complementary principle. We chose ultrasonic detection range as the region for obstacle detection when the obstacle is relatively near the robot, and the travelling road area in front of the robot is the region for a relatively-long-distance detection. The obstacle detection algorithm is adapted from a powerful background subtraction algorithm ViBe: Visual Background Extractor. We extracted an obstacle free region in front of the robot in the initial frame, this region provided a reference sample set of gray scale value for obstacle detection. Experiments of detecting different obstacles at different distances respectively, give the accuracy of the obstacle detection and the error percentage between the calculated size and the actual size of the detected obstacle. Experimental results show that the detection scheme can effectively detect obstacles in front of the robot and provide size of the obstacle with relatively high dimensional accuracy.

The cross education of strength and skill following unilateral strength training in the upper and lower limbs.

PubMed

Green, Lara A; Gabriel, David A

2018-04-18

Cross education is the strength gain or skill improvement transferred to the contralateral limb following unilateral training or practice. The present study examined the transfer of both strength and skill following a strength training program. Forty participants (20M, 20F) completed a 6-week unilateral training program of dominant wrist flexion or dorsiflexion. Strength, force variability, and muscle activity were assessed pre-training, post-training, and following 6-weeks of detraining (retention). Analyses of covariance compared the experimental limb (trained or untrained) to the control (dominant or non-dominant). There were no sex differences in the training response. Cross education of strength at post-training was 6% (p<0.01) in the untrained arm and 13% (p<0.01) in the untrained leg. Contralateral strength continued to increase following detraining to 15% in the arm (p<0.01) and 14% in the leg (p<0.01). There was no difference in strength gains between upper and lower limbs (p>0.05). Cross education of skill (force variability) demonstrated greater improvements in the untrained limbs compared to the control limbs during contractions performed without concurrent feedback. Significant increases in V-wave amplitude (p=0.02) and central activation (p<0.01) were highly correlated with contralateral strength gains. There was no change in agonist amplitude or motor unit firing rates in the untrained limbs (p>0.05). The neuromuscular mechanisms mirrored the force increases at post-training and retention supporting central drive adaptations of cross education. The continued strength increases at retention identified the presence of motor learning in cross education, as confirmed by force variability.

Impact of Performance Obstacles on Intensive Care Nurses‘ Workload, Perceived Quality and Safety of Care, and Quality of Working Life

PubMed Central

Gurses, Ayse P; Carayon, Pascale; Wall, Melanie

2009-01-01

Objectives To study the impact of performance obstacles on intensive care nurses‘ workload, quality and safety of care, and quality of working life (QWL). Performance obstacles are factors that hinder nurses‘ capacity to perform their job and that are closely associated with their immediate work system. Data Sources/Study Setting Data were collected from 265 nurses in 17 intensive care units (ICUs) between February and August 2004 via a structured questionnaire, yielding a response rate of 80 percent. Study Design A cross-sectional study design was used. Data were analyzed by correlation analyses and structural equation modeling. Principal Findings Performance obstacles were found to affect perceived quality and safety of care and QWL of ICU nurses. Workload mediated the impact of performance obstacles with the exception of equipment-related issues on perceived quality and safety of care as well as QWL. Conclusions Performance obstacles in ICUs are a major determinant of nursing workload, perceived quality and safety of care, and QWL. In general, performance obstacles increase nursing workload, which in turn negatively affect perceived quality and safety of care and QWL. Redesigning the ICU work system to reduce performance obstacles may improve nurses‘ work. PMID:19207589

Planning Process Obstacles and Opportunities.

ERIC Educational Resources Information Center

Doyle, Patricia C.

1997-01-01

Argues that obstacles exist in the Public Library Association (PLA) planning process that can be resolved by developing relationships between materials in the collection and PLA roles. Proposes changes to help reduce conflict in the PLA planning process and discusses process obstacles, relationships as the key providing better service, and…

Surface obstacles in pulsatile flow

NASA Astrophysics Data System (ADS)

Carr, Ian A.; Plesniak, Michael W.

2016-11-01

Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e. constant velocity unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Beyond the important practical applications, characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigated the wake of four canonical surface obstacles: hemisphere, cube, and circular cylinders with aspect ratio of 1:1 and 2:1. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings. This material is based in part upon work supported by the National Science Foundation under Grant Number CBET-1236351, and GW Centeor Biomimetics and Bioinspired Engineering (COBRE).

Advanced obstacle avoidance for a laser based wheelchair using optimised Bayesian neural networks.

PubMed

Trieu, Hoang T; Nguyen, Hung T; Willey, Keith

2008-01-01

In this paper we present an advanced method of obstacle avoidance for a laser based intelligent wheelchair using optimized Bayesian neural networks. Three neural networks are designed for three separate sub-tasks: passing through a door way, corridor and wall following and general obstacle avoidance. The accurate usable accessible space is determined by including the actual wheelchair dimensions in a real-time map used as inputs to each networks. Data acquisitions are performed separately to collect the patterns required for specified sub-tasks. Bayesian frame work is used to determine the optimal neural network structure in each case. Then these networks are trained under the supervision of Bayesian rule. Experiment results showed that compare to the VFH algorithm our neural networks navigated a smoother path following a near optimum trajectory.

Inertial navigation sensor integrated obstacle detection system

NASA Technical Reports Server (NTRS)

Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

1992-01-01

A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

United States Army physical readiness training: rationale and evaluation of the physical training doctrine.

PubMed

Knapik, Joseph J; Rieger, William; Palkoska, Frank; Van Camp, Steven; Darakjy, Salima

2009-07-01

This paper reviews the rationale and evaluations of Physical Readiness Training (PRT), the new U.S. Army physical training doctrine designed to improve soldiers' physical capability for military operations. The purposes of PRT are to improve physical fitness, prevent injuries, progressively train soldiers, and develop soldiers' self-confidence and discipline. The PRT follows the principles of progressive overload, regularity, specificity, precision, variety, and balance. Specificity was achieved by examining the standard list of military (warrior) tasks and determining 1) the physical requirements, 2) the fitness components involved, and 3) the training activities that most likely could improve the military tasks. Injury-prevention features include reduced running mileage, exercise variety (cross-training), and gradual, progressive training. In 3 military field studies, the overall adjusted risk of injury was 1.5-1.8 times higher in groups of soldiers performing traditional military physical training programs when compared with groups using a PRT program. Scores on the Army Physical Fitness Test were similar or higher in groups using PRT programs. In an 8-week laboratory study comparing PRT with a weightlifting/running program, both programs resulted in major improvements in militarily relevant tasks (e.g., 3.2-km walk/run with 32-kg load, 400-m run with 18-kg load, 5- to 30-second rushes to and from prone position, 80-kg casualty drag, obstacle course). When compared with traditional military physical training programs, PRT consistently resulted in fewer injuries and in equal or greater improvements in fitness and military task performance.

Guidelines for Enhancement of Visual Conspicuity of Trains at Grade Crossings

DOT National Transportation Integrated Search

1975-05-01

This report summarizes a comprehensive study of potential means of reducing the probability of train-motor vehicle collisions at railroad-highway grade crossings through enhancement of the visual conspicuity of locomotives. Passive techniques are rev...

Identification and analysis of obstacles in bioterrorism preparedness and response

NASA Astrophysics Data System (ADS)

Sincavage, Suzanne Michele

The focus of this study was to identify and analyze the obstacles to bioterrorism preparedness and response facing emergency management agencies and public authorities. In order to establish the limits of this discussion, the obstacles will examine a combined conceptual framework of public health, environmental security and social response. The interdisciplinary characteristics of this framework are ideal for addressing the issue of bioterrorism because of its simultaneous impact, which encompasses the complex interrelationships that pertain to public health and national security and social response. Based on a review of literature, the obstacles presented range from the absence of an effective surveillance system for biological terrorism related diseases to the inadequate training of first responders in bioterrorism preparedness and the difficult challenges of a mass casualty situation and the intense pressures associated with the crisis response. Furthermore, the impending reality of bioterrorism will further illustrate a close examination of the characteristics and management of three major biowarfare agents---anthrax, plague and smallpox. Finally, to provide a realistic understanding of the impact of bioterrorism, three case studies of actual events and two hypothetical scenarios will be discussed. Specifically, the discussion will provide the following three unconventional terrorist attacks: the recent anthrax attacks of 2001, the Aum Shinrikyo's attack of the Tokyo subway in 1995, and the Rajneeshees' use of salmonella poisoning in 1994. The inclusion of the hypothetical scenarios of two massive outbreaks of smallpox and anthrax will be presented to illuminate the seriousness and magnitude of the threat of bioterrorism and the probable consequences of failing to overcome the obstacles presented in this study. The importance of this research cannot be overemphasized, the threat is undeniably serious, and the potential for biological agents to cause devastating

Utilizing Cross-Cultural Curricula To Improve Interpersonal Job Skills Training.

ERIC Educational Resources Information Center

Barker, Shirl A.

2002-01-01

An experimental group of 65 secondary vocational students received cross-cultural training focused on interpersonal communication and job skills. Compered with 65 controls, the experimental group had significantly better interpersonal skills. Differences in terms of gender, ethnicity, and rural/urban location were found. (Contains 18 references.)…

Indoor Navigation from Point Clouds: 3d Modelling and Obstacle Detection

NASA Astrophysics Data System (ADS)

Díaz-Vilariño, L.; Boguslawski, P.; Khoshelham, K.; Lorenzo, H.; Mahdjoubi, L.

2016-06-01

In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

Shock interaction behind a pair of cylindrical obstacles

NASA Astrophysics Data System (ADS)

Liu, Heng; Mazumdar, Raoul; Eliasson, Veronica

2014-11-01

The body of work focuses on two-dimensional numerical simulations of shock interaction with a pair of cylindrical obstacles, varying the obstacle separation and incident shock strength. With the shock waves propagating parallel to the center-line between the two cylindrical obstacles, the shock strengths simulated vary from a Mach of 1.4 to a Mach of 2.4, against a wide range of obstacle separation distance to their diameters. These cases are simulated via a software package called Overture, which is used to solve the inviscid Euler equations of gas dynamics on overlapping grids with adaptive mesh refinement. The goal of these cases is to find a so-called ``safe'' region for obstacle spacing and varying shock Mach numbers, such that the pressure in the ``safe'' region is reduced downstream of the obstacles. The benefits apply to both building and armor design for the purpose of shock wave mitigation to keep humans and equipment safe. The results obtained from the simulations confirm that the length of the ``safe'' region and the degree of shock wave attenuation depend on the ratio of obstacle separation distance to obstacle diameter. The influence of various Mach number is also discussed.

Detecting Negative Obstacles by Use of Radar

NASA Technical Reports Server (NTRS)

Mittskus, Anthony; Lux, James

2006-01-01

Robotic land vehicles would be equipped with small radar systems to detect negative obstacles, according to a proposal. The term "negative obstacles" denotes holes, ditches, and any other terrain features characterized by abrupt steep downslopes that could be hazardous for vehicles. Video cameras and other optically based obstacle-avoidance sensors now installed on some robotic vehicles cannot detect obstacles under adverse lighting conditions. Even under favorable lighting conditions, they cannot detect negative obstacles. A radar system according to the proposal would be of the frequency-modulation/ continuous-wave (FM/CW) type. It would be installed on a vehicle, facing forward, possibly with a downward slant of the main lobe(s) of the radar beam(s) (see figure). It would utilize one or more wavelength(s) of the order of centimeters. Because such wavelengths are comparable to the characteristic dimensions of terrain features associated with negative hazards, a significant amount of diffraction would occur at such features. In effect, the diffraction would afford a limited ability to see corners and to see around corners. Hence, the system might utilize diffraction to detect corners associated with negative obstacles. At the time of reporting the information for this article, preliminary analyses of diffraction at simple negative obstacles had been performed, but an explicit description of how the system would utilize diffraction was not available.

The Training Characteristics of the World's Most Successful Female Cross-Country Skier.

PubMed

Solli, Guro S; Tønnessen, Espen; Sandbakk, Øyvind

2017-01-01

The main aim of this study was to investigate the training characteristics of the most successful female cross-country skier ever during the best period of her career. The participant won six gold medals at the Olympic Games, 18 gold medals at the World Championship, and 110 World Cup victories. Day-to-day training diary data, interviews, and physiological tests were analyzed. Training data was systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and mode (running, cycling, and skiing/roller skiing), followed by a division into different periodization phases. Specific sessions utilized in the various periodization periods and the day-to-day periodization of training, in connection with altitude camps and tapering toward major championships, were also analyzed. Following a 12-year nonlinear increase in training load, the annual training volume during the five consecutive successful years stabilized at 937 ± 25 h, distributed across 543 ± 9 sessions. During these 5 years, total training time was distributed as 90.6% endurance-, 8.0% strength-, and 1.4% speed-training, with endurance-training time consisting of 92.3 ± 0.3% LIT, 2.9 ± 0.5% MIT, and 4.8 ± 0.5% HIT. Total LIT-time consisted of 21% warm-up, 14% sessions <90 min, and 65% long-duration sessions >90 min. While the total number of LIT sessions remained stable across phases (32 sessions), total LIT-time was reduced from GP (76 h/month) to SP (68 h/month) and CP (55 h/month). MIT-time decreased from GP (2.8 h/month) to SP (2.2 h/month) and CP (1 h/month). HIT-time increased from GP (2.8 h/month) to SP (3.2 h/month) and CP (4.7 h/month). Altitude training accounted for 18-25% of annual training volume and performed across relatively short training camps (≤16 days) with a clear reduction of HIT training, but increased total and LIT volume compared to sea-level training. Training before international championships included

Strategies for obstacle avoidance during walking in the cat.

PubMed

Chu, Kevin M I; Seto, Sandy H; Beloozerova, Irina N; Marlinski, Vladimir

2017-08-01

Avoiding obstacles is essential for successful navigation through complex environments. This study aimed to clarify what strategies are used by a typical quadruped, the cat, to avoid obstacles during walking. Four cats walked along a corridor 2.5 m long and 25 or 15 cm wide. Obstacles, small round objects 2.5 cm in diameter and 1 cm in height, were placed on the floor in various locations. Movements of the paw were recorded with a motion capture and analysis system (Visualeyez, PTI). During walking in the wide corridor, cats' preferred strategy for avoiding a single obstacle was circumvention, during which the stride direction changed while stride duration and swing-to-stride duration ratio were preserved. Another strategy, stepping over the obstacle, was used during walking in the narrow corridor, when lateral deviations of walking trajectory were restricted. Stepping over the obstacle involved changes in two consecutive strides. The stride preceding the obstacle was shortened, and swing-to-stride ratio was reduced. The obstacle was negotiated in the next stride of increased height and normal duration and swing-to-stride ratio. During walking on a surface with multiple obstacles, both strategies were used. To avoid contact with the obstacle, cats placed the paw away from the object at a distance roughly equal to the diameter of the paw. During obstacle avoidance cats prefer to alter muscle activities without altering the locomotor rhythm. We hypothesize that a choice of the strategy for obstacle avoidance is determined by minimizing the complexity of neuro-motor processes required to achieve the behavioral goal. NEW & NOTEWORTHY In a study of feline locomotor behavior we found that the preferred strategy to avoid a small obstacle is circumvention. During circumvention, stride direction changes but length and temporal structure are preserved. Another strategy, stepping over the obstacle, is used in narrow walkways. During overstepping, two strides adjust. A stride

Mission-Based Serious Games for Cross-Cultural Communication Training

NASA Technical Reports Server (NTRS)

Schrider, Peter J.; Friedland, LeeEllen; Valente, Andre; Camacho, Joseph

2011-01-01

Appropriate cross-cultural communication requires a critical skill set that is increasingly being integrated into regular military training regimens. By enabling a higher order of communication skills, military personnel are able to interact more effectively in situations that involve local populations, host nation forces, and multinational partners. The Virtual Cultural Awareness Trainer (VCAT) is specifically designed to help address these needs. VCAT is deployed by Joint Forces Command (JFCOM) on Joint Knowledge Online (JKO) as a means to provide online, mission-based culture and language training to deploying and deployed troops. VCAT uses a mix of game-based learning, storytelling, tutoring, and remediation to assist in developing the component skills required for successful intercultural communication in mission-based settings.

Speeded Reaching Movements around Invisible Obstacles

PubMed Central

Hudson, Todd E.; Wolfe, Uta; Maloney, Laurence T.

2012-01-01

We analyze the problem of obstacle avoidance from a Bayesian decision-theoretic perspective using an experimental task in which reaches around a virtual obstacle were made toward targets on an upright monitor. Subjects received monetary rewards for touching the target and incurred losses for accidentally touching the intervening obstacle. The locations of target-obstacle pairs within the workspace were varied from trial to trial. We compared human performance to that of a Bayesian ideal movement planner (who chooses motor strategies maximizing expected gain) using the Dominance Test employed in Hudson et al. (2007). The ideal movement planner suffers from the same sources of noise as the human, but selects movement plans that maximize expected gain in the presence of that noise. We find good agreement between the predictions of the model and actual performance in most but not all experimental conditions. PMID:23028276

Primary care resident perceived preparedness to deliver cross-cultural care: an examination of training and specialty differences.

PubMed

Greer, Joseph A; Park, Elyse R; Green, Alexander R; Betancourt, Joseph R; Weissman, Joel S

2007-08-01

Previous research has shown that resident physicians report differences in training across primary care specialties, although limited data exist on education in delivering cross-cultural care. The goals of this study were to identify factors that relate to primary care residents' perceived preparedness to provide cross-cultural care and to explore the extent to which these perceptions vary across primary care specialties. Cross-sectional, national mail survey of resident physicians in their last year of training. Eleven hundred fifty primary care residents specializing in family medicine (27%), internal medicine (23%), pediatrics (26%), and obstetrics/gynecology (OB/GYN) (24%). Male residents as well as those who reported having graduated from U.S. medical schools, access to role models, and a greater cross-cultural case mix during residency felt more prepared to deliver cross-cultural care. Adjusting for these demographic and clinical factors, family practice residents were significantly more likely to feel prepared to deliver cross-cultural care compared to internal medicine, pediatric, and OB/GYN residents. Yet, when the quantity of instruction residents reported receiving to deliver cross-cultural care was added as a predictor, specialty differences became nonsignificant, suggesting that training opportunities better account for the variability in perceived preparedness than specialty. Across primary care specialties, residents reported different perceptions of preparedness to deliver cross-cultural care. However, this variation was more strongly related to training factors, such as the amount of instruction physicians received to deliver such care, rather than specialty affiliation. These findings underscore the importance of formal education to enhance residents' preparedness to provide cross-cultural care.

Impact of gender-based career obstacles on the working status of women physicians in Japan.

PubMed

Nomura, Kyoko; Gohchi, Kengo

2012-11-01

Research has shown that women physicians work fewer hours and are more likely to become inactive professionally and to switch to part-time labor, compared with their male counterparts. The published literature suggests that a gender disparity still exists in medicine which may decrease work motivation among women physicians. The authors investigated whether the experience and the perception of gender-based career obstacles among women physicians in Japan are associated with their working status (i.e., full-time vs. part-time). The present cross-sectional study is based on surveys of alumnae from 13 private medical schools in Japan conducted between June 2009 and May 2011. Of those who agreed to participate in this study, 1684 completed a self-administered questionnaire (overall response rate 83%). Experience of gender-based obstacles was considered affirmative if a woman physician had been overlooked for opportunities of professional advancement based on gender. Perception of gender-based obstacles referred to the self-reported degree of difficulty of promotion and opportunities for a position in higher education. Approximately 20% of the study participants responded that they experienced gender-based obstacles while 24% answered that they were not sure. The scores for perception of gender-based career obstacles were statistically higher among part-time workers compared with full-time workers (mean difference = 1.20, 95% CI: 0.39-2.00). Adjusting for age, marital status, the presence of children, workplace, board certification, holding a PhD degree, overall satisfaction of being a physician, and household income, stepwise logistic regression models revealed that physicians with the strongest perception of gender-based career obstacles were more likely to work part-time rather than full-time (OR, 0.59; 95% CI: 0.40-0.88). Although the experience of gender-based obstacles was not associated with working status among women physicians, the results demonstrated that a

Obstacle Avoidance for Quadcopter using Ultrasonic Sensor

NASA Astrophysics Data System (ADS)

Fazlur Rahman, Muhammad; Adhy Sasongko, Rianto

2018-04-01

An obstacle avoidance system is being proposed. The system will combine available flight controller with a proposed avoidance method as a proof of concept. Quadcopter as a UAV is integrated with the system which consist of several modes in order to do avoidance. As the previous study, obstacle will be determined using ultrasonic sensor and servo. As result, the quadcopter will move according to its mode and successfully avoid obstacle.

Textiles and Training in Portugal.

ERIC Educational Resources Information Center

Andrez, Jaime Serrao; Dias, Mario Caldeira

Analyzing the role of vocational training in an economic sector that is declining in Portugal, this document consists of five chapters, a bibliography, and a list of training organizations. An introduction tells why the study is important and explains that the major obstacles to development of the Portuguese textile and clothing sector are the…

Primary Care Resident Perceived Preparedness to Deliver Cross-cultural Care: An Examination of Training and Specialty Differences

PubMed Central

Park, Elyse R.; Green, Alexander R.; Betancourt, Joseph R.; Weissman, Joel S.

2007-01-01

Objective Previous research has shown that resident physicians report differences in training across primary care specialties, although limited data exist on education in delivering cross-cultural care. The goals of this study were to identify factors that relate to primary care residents’ perceived preparedness to provide cross-cultural care and to explore the extent to which these perceptions vary across primary care specialties. Design Cross-sectional, national mail survey of resident physicians in their last year of training. Participants Eleven hundred fifty primary care residents specializing in family medicine (27%), internal medicine (23%), pediatrics (26%), and obstetrics/gynecology (OB/GYN) (24%). Results Male residents as well as those who reported having graduated from U.S. medical schools, access to role models, and a greater cross-cultural case mix during residency felt more prepared to deliver cross-cultural care. Adjusting for these demographic and clinical factors, family practice residents were significantly more likely to feel prepared to deliver cross-cultural care compared to internal medicine, pediatric, and OB/GYN residents. Yet, when the quantity of instruction residents reported receiving to deliver cross-cultural care was added as a predictor, specialty differences became nonsignificant, suggesting that training opportunities better account for the variability in perceived preparedness than specialty. Conclusions Across primary care specialties, residents reported different perceptions of preparedness to deliver cross-cultural care. However, this variation was more strongly related to training factors, such as the amount of instruction physicians received to deliver such care, rather than specialty affiliation. These findings underscore the importance of formal education to enhance residents’ preparedness to provide cross-cultural care. PMID:17516107

Women’s orgasm obstacles: A qualitative study

PubMed Central

Nekoolaltak, Maryam; Keshavarz, Zohreh; Simbar, Masoumeh; Nazari, Ali Mohammad; Baghestani, Ahmad Reza

2017-01-01

Background: Woman’s orgasm plays a vital role in sexual compatibility and marital satisfaction. Orgasm in women is a learnable phenomenon that is influenced by several factors. Objective: The aim of this study is exploring obstacles to orgasm in Iranian married women. Materials and Methods: This qualitative study with directed content analysis approach was conducted in 2015-2016, on 20 Iranian married women who were individually interviewed at two medical clinics in Tehran, Iran. Results: Orgasm obstacles were explored in one category, 4 subcategories, and 25 codes. The main category was “Multidimensionality of women’s orgasm obstacles”. Subcategories and some codes included: Physical obstacles (wife’s or husband’s boredom, vaginal infection, insufficient vaginal lubrication), psychological obstacles (lack of sexual knowledge, shame, lack of concentration on sex due to household and children problems), relational obstacles (husband’s hurry, having a dispute and annoyance with spouse) and contextual obstacles (Irregular sleep hours, lack of privacy and inability to separate children’s bedroom from their parents, lack of peace at home). Conclusion: For prevention or treatment of female orgasm disorders, attention to physical factors is not enough. Obtaining a comprehensive history about physical, psychological, relational and contextual dimensions of woman’s life is necessary. PMID:29082366

The Training Characteristics of the World's Most Successful Female Cross-Country Skier

PubMed Central

Solli, Guro S.; Tønnessen, Espen; Sandbakk, Øyvind

2017-01-01

The main aim of this study was to investigate the training characteristics of the most successful female cross-country skier ever during the best period of her career. The participant won six gold medals at the Olympic Games, 18 gold medals at the World Championship, and 110 World Cup victories. Day-to-day training diary data, interviews, and physiological tests were analyzed. Training data was systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and mode (running, cycling, and skiing/roller skiing), followed by a division into different periodization phases. Specific sessions utilized in the various periodization periods and the day-to-day periodization of training, in connection with altitude camps and tapering toward major championships, were also analyzed. Following a 12-year nonlinear increase in training load, the annual training volume during the five consecutive successful years stabilized at 937 ± 25 h, distributed across 543 ± 9 sessions. During these 5 years, total training time was distributed as 90.6% endurance-, 8.0% strength-, and 1.4% speed-training, with endurance-training time consisting of 92.3 ± 0.3% LIT, 2.9 ± 0.5% MIT, and 4.8 ± 0.5% HIT. Total LIT-time consisted of 21% warm-up, 14% sessions <90 min, and 65% long-duration sessions >90 min. While the total number of LIT sessions remained stable across phases (32 sessions), total LIT-time was reduced from GP (76 h/month) to SP (68 h/month) and CP (55 h/month). MIT-time decreased from GP (2.8 h/month) to SP (2.2 h/month) and CP (1 h/month). HIT-time increased from GP (2.8 h/month) to SP (3.2 h/month) and CP (4.7 h/month). Altitude training accounted for 18–25% of annual training volume and performed across relatively short training camps (≤16 days) with a clear reduction of HIT training, but increased total and LIT volume compared to sea-level training. Training before international championships

Optimal consensus algorithm integrated with obstacle avoidance

NASA Astrophysics Data System (ADS)

Wang, Jianan; Xin, Ming

2013-01-01

This article proposes a new consensus algorithm for the networked single-integrator systems in an obstacle-laden environment. A novel optimal control approach is utilised to achieve not only multi-agent consensus but also obstacle avoidance capability with minimised control efforts. Three cost functional components are defined to fulfil the respective tasks. In particular, an innovative nonquadratic obstacle avoidance cost function is constructed from an inverse optimal control perspective. The other two components are designed to ensure consensus and constrain the control effort. The asymptotic stability and optimality are proven. In addition, the distributed and analytical optimal control law only requires local information based on the communication topology to guarantee the proposed behaviours, rather than all agents' information. The consensus and obstacle avoidance are validated through simulations.

A stereo vision-based obstacle detection system in vehicles

NASA Astrophysics Data System (ADS)

Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun

2008-02-01

Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

Statistics of dislocation pinning at localized obstacles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, A.; Bhattacharya, M., E-mail: mishreyee@vecc.gov.in; Barat, P.

2014-10-14

Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning ofmore » dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.« less

Summer training factors and risk of musculoskeletal injury among high school cross-country runners.

PubMed

Rauh, Mitchell J

2014-10-01

Prospective cohort. To examine the relationship between summer training practices and risk of injury during the first month of a high school interscholastic cross-country season. Several prospective studies have reported a high incidence of injury in adolescent cross-country runners. However, limited reports exist on the role of summer training practices and risk of injury among these runners. Four hundred twenty-one athletes (186 girls, 235 boys) who competed in interscholastic cross-country were followed during a cross-country season. At the start of the season, all participants completed a questionnaire regarding summer training routines. Time-loss, running-related injuries were tracked during the subsequent season. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of initial injury during the first month of the season associated with summer training variables. Sixty-seven runners (15.9%) had a confirmed injury during the first month of the season, with a higher percent among girls (19.4%) than boys (13.2%) (P = .06). Overall, 60.1% of the participants ran during the summer prior to the season, with a significantly higher percent among girls (71.5%) than boys (51.1%) (P<.0001). Overall, no significant association (OR = 0.9; 95% CI: 0.5, 1.5; P = .90) was found between not running sometime during the preceding summer and increased risk of initial injury during the first month of the season. Among only the runners who ran during the summer, after adjusting for sex and prior injury, first-month injuries were more common among those who did not frequently alternate short and long mileage on different days (OR = 3.0; 95% CI: 1.4, 6.4; P = .005), and/or who ran 8 weeks or fewer (OR = 2.7; 95% CI: 1.2, 5.8; P = .01) during their summer training. Running 8 weeks or fewer (P = .03), not frequently alternating mileage on different days (P = .01), and running a higher percentage of time on predominantly

Kinematic effect of Nintendo WiiTM sports program exercise on obstacle gait in elderly women with falling risk

PubMed Central

Jung, Dae-In; Ko, Dae-Sik; Jeong, Mi-Ae

2015-01-01

[Purpose] This study evaluated the changes in balance ability and obstacle gait after lumbar stabilization exercise and Nintendo WiiTM Sports in elderly at risk for falls. [Subjects and Methods] Twenty-four elderly women with at risk for falls were randomly divided into the control, lumbar stabilization exercise, and Nintendo Wii Sports groups. Static balance was measured by the Berg Balance Scale and functional reach test, dynamic balance by the timed up-and-go test, and obstacle negotiation function by crossing velocity and maximum vertical heel clearance. [Results] Both the lumbar stabilization exercise and Nintendo Wii Sports groups showed significant improvements in obstacle negotiation function after the exercise compared to the control group. Berg Balance Scale and functional reach test scores were greater in the lumbar stabilization exercise group, while the timed up-and-go test time was significantly better in the Nintendo Wii Sports groups. [Conclusion] Lumbar stabilization exercises and Nintendo Wii Sports improve falling related balance and obstacle negotiation function in elderly women at risk for falls. PMID:26157228

Kinematic effect of Nintendo Wii(TM) sports program exercise on obstacle gait in elderly women with falling risk.

PubMed

Jung, Dae-In; Ko, Dae-Sik; Jeong, Mi-Ae

2015-05-01

[Purpose] This study evaluated the changes in balance ability and obstacle gait after lumbar stabilization exercise and Nintendo Wii(TM) Sports in elderly at risk for falls. [Subjects and Methods] Twenty-four elderly women with at risk for falls were randomly divided into the control, lumbar stabilization exercise, and Nintendo Wii Sports groups. Static balance was measured by the Berg Balance Scale and functional reach test, dynamic balance by the timed up-and-go test, and obstacle negotiation function by crossing velocity and maximum vertical heel clearance. [Results] Both the lumbar stabilization exercise and Nintendo Wii Sports groups showed significant improvements in obstacle negotiation function after the exercise compared to the control group. Berg Balance Scale and functional reach test scores were greater in the lumbar stabilization exercise group, while the timed up-and-go test time was significantly better in the Nintendo Wii Sports groups. [Conclusion] Lumbar stabilization exercises and Nintendo Wii Sports improve falling related balance and obstacle negotiation function in elderly women at risk for falls.

Mathematical Models of Smart Obstacles

DTIC Science & Technology

2006-10-01

Matematica “G. Castelnuovo” Università di Roma “La Sapienza”, Piazzale Aldo Moro 2 00185 Roma Italy Ph. N. +39-06-49913282, FAX N. +39-06...Dipartimento di Matematica G. Castelnuovo Università di Roma La Sapienza, Piazzale Aldo Moro 2 00185 Roma Italy 8. PERFORMING ORGANIZATION REPORT NUMBER 9... Matematica G. Castelnuovo Università di Roma “La Sapienza” 00185 Roma, Italy 2 Smart (or active) obstacles are obstacles that when illuminated by an

Imaging objects behind small obstacles using axicon lens

NASA Astrophysics Data System (ADS)

Perinchery, Sandeep M.; Shinde, Anant; Murukeshan, V. M.

2017-06-01

Axicon lenses are conical prisms, which are known to focus a light source to a line comprising of multiple points along the optical axis. In this study, we analyze the potential of axicon lenses to view, image and record the object behind opaque obstacles in free space. The advantage of an axicon lens over a regular lens is demonstrated experimentally. Parameters such as obstacle size, object and the obstacle position in the context of imaging behind obstacles are tested using Zemax optical simulation. This proposed concept can be easily adapted to most of the optical imaging methods and microscopy modalities.

Visualization of deflagration-to-detonation transitions in a channel with repeated obstacles using a hydrogen-oxygen mixture

NASA Astrophysics Data System (ADS)

Maeda, S.; Minami, S.; Okamoto, D.; Obara, T.

2016-09-01

The deflagration-to-detonation transition in a 100 mm square cross-section channel was investigated for a highly reactive stoichiometric hydrogen oxygen mixture at 70 kPa. Obstacles of 5 mm width and 5, 10, and 15 mm heights were equally spaced 60 mm apart at the bottom of the channel. The phenomenon was investigated primarily by time-resolved schlieren visualization from two orthogonal directions using a high-speed video camera. The detonation transition occurred over a remarkably short distance within only three or four repeated obstacles. The global flame speed just before the detonation transition was well below the sound speed of the combustion products and did not reach the sound speed of the initial unreacted gas for tests with an obstacle height of 5 and 10 mm. These results indicate that a detonation transition does not always require global flame acceleration beyond the speed of sound for highly reactive combustible mixtures. A possible mechanism for this detonation initiation was the mixing of the unreacted and reacted gas in the vicinity of the flame front convoluted by the vortex present behind each obstacle, and the formation of a hot spot by the shock wave. The final onset of the detonation originated from the unreacted gas pocket, which was surrounded by the obstacle downstream face and the channel wall.

Identifying Complex Cultural Interactions in the Instructional Design Process: A Case Study of a Cross-Border, Cross-Sector Training for Innovation Program

ERIC Educational Resources Information Center

Russell, L. Roxanne; Kinuthia, Wanjira L.; Lokey-Vega, Anissa; Tsang-Kosma, Winnie; Madathany, Reeny

2013-01-01

The purpose of this research is to identify complex cultural dynamics in the instructional design process of a cross-sector, cross-border training environment by applying Young's (2009) Culture-Based Model (CBM) as a theoretical framework and taxonomy for description of the instructional design process under the conditions of one case. This…

A Qualitative Study on the Obstacles Preventing the Successful Implementation of Web 2.0 in Corporate Learning

ERIC Educational Resources Information Center

Estrada, Luis

2012-01-01

The purpose of this study was to identify the obstacles to the adoption of Web 2.0 technologies as part of corporate learning solutions and strategies. The study followed a qualitative inquiry approach. The sample consisted of 20 corporate learning professionals who are members of the American Society for Training and Development (ASTD) social…

Entrepreneurial Training Needs of Illiterate Women in Cross River State, Nigeria

ERIC Educational Resources Information Center

Ingwu, Emmanuel U.; Okey, Stella-Maris A.

2013-01-01

In order to improve on the curriculum and participation rate of adult learners in the current Adult Basic Education (ABE) program in Nigeria, this explorative study investigated the entrepreneurial (or vocational) training needs of illiterate women in Cross River State (CRS). Three research questions were posed to elicit from the participants…

Passive detection of subpixel obstacles for flight safety

NASA Astrophysics Data System (ADS)

Nixon, Matthew D.; Loveland, Rohan C.

2001-12-01

Military aircraft fly below 100 ft. above ground level in support of their missions. These aircraft include fixed and rotary wing and may be manned or unmanned. Flying at these low altitudes presents a safety hazard to the aircrew and aircraft, due to the occurrences of obstacles within the aircraft's flight path. The pilot must rely on eyesight and in some cases, infrared sensors to see obstacles. Many conditions can exacerbate visibility creating a situation in which obstacles are essentially invisible, creating a safety hazard, even to an alerted aircrew. Numerous catastrophic accidents have occurred in which aircraft have collided with undetected obstacles. Accidents of this type continue to be a problem for low flying military and commercial aircraft. Unmanned Aerial Vehicles (UAVs) have the same problem, whether operating autonomously or under control of a ground operator. Boeing-SVS has designed a passive, small, low- cost (under $100k) gimbaled, infrared imaging based system with advanced obstacle detection algorithms. Obstacles are detected in the infrared band, and linear features are analyzed by innovative cellular automata based software. These algorithms perform detection and location of sub-pixel linear features. The detection of the obstacles is performed on a frame by frame basis, in real time. Processed images are presented to the aircrew on their display as color enhanced features. The system has been designed such that the detected obstacles are displayed to the aircrew in sufficient time to react and maneuver the aircraft to safety. A patent for this system is on file with the US patent office, and all material herein should be treated accordingly.

Foot strike patterns after obstacle clearance during running.

PubMed

Scholten, Shane D; Stergiou, Nicholas; Hreljac, Alan; Houser, Jeremy; Blanke, Daniel; Alberts, L Russell

2002-01-01

Running over obstacles of sufficient height requires heel strike (HS) runners to make a transition in landing strategy to a forefoot (FF) strike, resulting in similar ground reaction force patterns to those observed while landing from a jump. Identification of the biomechanical variables that distinguish between the landing strategies may offer some insight into the reasons that the transition occurs. The purpose of this study was to investigate the difference in foot strike patterns and kinetic parameters of heel strike runners between level running and running over obstacles of various heights. Ten heel strike subjects ran at their self-selected pace under seven different conditions: unperturbed running (no obstacle) and over obstacles of six different heights (10%, 12.5%, 15%, 17.5%, 20%, and 22.5% of their standing height). The obstacle was placed directly before a Kistler force platform. Repeated measures ANOVAs were performed on the subject means of selected kinetic parameters. The statistical analysis revealed significant differences (P < 0.004) for all of the parameters analyzed. The evaluation of the center of pressure and the ground reaction forces indicated that the foot strike patterns were affected by the increased obstacle height. Between the 12.5% and 15% obstacle conditions, the group response changed from a heel strike to a forefoot strike pattern. At height > 15%, the pattern was more closely related to the foot strike patterns found in jumping activities. This strategy change may represent a gait transition effected as a mechanism to protect against increased impact forces. Greater involvement of the ankle and the calf muscles could have assisted in attenuating the increased impact forces while maintaining speed after clearing the obstacle.

New Technologies and Training in Metalworking.

ERIC Educational Resources Information Center

Belitsky, A. Harvey

This report reviews the role of technological factors in metalworking and the training required to adapt to new metalworking technologies. Focus is on whether firms that have adopted the new technologies have encountered obstacles in training and developing the skills of their work forces. The report is organized in three parts. Parts I and II…

Obstacle avoidance for redundant robots using configuration control

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor); Colbaugh, Richard D. (Inventor); Glass, Kristin L. (Inventor)

1992-01-01

A redundant robot control scheme is provided for avoiding obstacles in a workspace during the motion of an end effector along a preselected trajectory by stopping motion of the critical point on the robot closest to the obstacle when the distance between is reduced to a predetermined sphere of influence surrounding the obstacle. Algorithms are provided for conveniently determining the critical point and critical distance.

Nursing Training in the Brazilian Red Cross in the 1940s: a Foucaultian approach.

PubMed

Mecone, Márcia Cristina da Cruz; Freitas, Genival Fernandes de; Bonini, Bárbara Barrionuevo

2015-12-01

Objectives To identify and analyze the discursive statements that characterizes the training of human resources in nursing in the 1940s by the Brazilian Red Cross. Method The approach of the documentary sources was through the assumptions of the Historical Method and they were questioned by using the thought of Michel Foucault. Results Historically, a peculiar model, the military teaching model, influenced the training of human resources in nursing, especially in the 1940s. The Brazilian Red Cross was linked to the Ministry of War and its nursing education had an emphasis on moral conduct, discipline, and respect for hierarchy, culminating in the production of nurses' "docile bodies". The attributes expected of nurses constituted the triad in the professional formation identity at that time: dedication, discipline and obedience. Conclusion The military model still reverberates practices in training of nurses in the present, as in the management, care and education in nursing.

Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots

PubMed Central

Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

2014-01-01

Neurobiological studies have shown that insects are able to adapt leg movements and posture for obstacle negotiation in changing environments. Moreover, the distance to an obstacle where an insect begins to climb is found to be a major parameter for successful obstacle negotiation. Inspired by these findings, we present an adaptive neural control mechanism for obstacle negotiation behavior in hexapod robots. It combines locomotion control, backbone joint control, local leg reflexes, and neural learning. While the first three components generate locomotion including walking and climbing, the neural learning mechanism allows the robot to adapt its behavior for obstacle negotiation with respect to changing conditions, e.g., variable obstacle heights and different walking gaits. By successfully learning the association of an early, predictive signal (conditioned stimulus, CS) and a late, reflex signal (unconditioned stimulus, UCS), both provided by ultrasonic sensors at the front of the robot, the robot can autonomously find an appropriate distance from an obstacle to initiate climbing. The adaptive neural control was developed and tested first on a physical robot simulation, and was then successfully transferred to a real hexapod robot, called AMOS II. The results show that the robot can efficiently negotiate obstacles with a height up to 85% of the robot's leg length in simulation and 75% in a real environment. PMID:24523694

Effects of Pelvic and Core Strength Training on High School Cross-Country Race Times.

PubMed

Clark, Anne W; Goedeke, Maggie K; Cunningham, Saengchoy R; Rockwell, Derek E; Lehecka, Bryan J; Manske, Robert C; Smith, Barbara S

2017-08-01

Clark, AW, Goedeke, MK, Cunningham, SR, Rockwell, DE, Lehecka, BJ, Manske, RC, and Smith, BS. Effects of pelvic and core strength training on high school cross-country race times. J Strength Cond Res 31(8): 2289-2295, 2017-There is only limited research examining the effect of pelvic and core strength training on running performance. Pelvic and core muscle fatigue is believed to contribute to excess motion along frontal and transverse planes which decreases efficiency in normal sagittal plane running motions. The purpose of this study was to determine whether adding a 6-week pelvic and core strengthening program resulted in decreased race times in high school cross-country runners. Thirty-five high school cross-country runners (14-19 years old) from 2 high schools were randomly assigned to a strengthening group (experimental) or a nonstrengthening group (control). All participants completed 4 standardized isometric strength tests for hip abductors, adductors, extensors, and core musculature in a test-retest design. The experimental group performed a 6-week pelvic and core strengthening program along with their normal training. Participants in the control group performed their normal training without additional pelvic and core strengthening. Baseline, 3-week, and 6-week race times were collected using a repeated measures design. No significant interaction between experimental and control groups regarding decreasing race times and increasing pelvic and core musculature strength occurred over the 6-week study period. Both groups increased strength and decreased overall race times. Clinically significant findings reveal a 6-week pelvic and core stability strengthening program 3 times a week in addition to coach led team training may help decrease race times.

Obstacle Detection Algorithms for Aircraft Navigation: Performance Characterization of Obstacle Detection Algorithms for Aircraft Navigation

NASA Technical Reports Server (NTRS)

Kasturi, Rangachar; Camps, Octavia; Coraor, Lee

2000-01-01

The research reported here is a part of NASA's Synthetic Vision System (SVS) project for the development of a High Speed Civil Transport Aircraft (HSCT). One of the components of the SVS is a module for detection of potential obstacles in the aircraft's flight path by analyzing the images captured by an on-board camera in real-time. Design of such a module includes the selection and characterization of robust, reliable, and fast techniques and their implementation for execution in real-time. This report describes the results of our research in realizing such a design. It is organized into three parts. Part I. Data modeling and camera characterization; Part II. Algorithms for detecting airborne obstacles; and Part III. Real time implementation of obstacle detection algorithms on the Datacube MaxPCI architecture. A list of publications resulting from this grant as well as a list of relevant publications resulting from prior NASA grants on this topic are presented.

Range Sensor-Based Efficient Obstacle Avoidance through Selective Decision-Making.

PubMed

Shim, Youngbo; Kim, Gon-Woo

2018-03-29

In this paper, we address a collision avoidance method for mobile robots. Many conventional obstacle avoidance methods have been focused solely on avoiding obstacles. However, this can cause instability when passing through a narrow passage, and can also generate zig-zag motions. We define two strategies for obstacle avoidance, known as Entry mode and Bypass mode. Entry mode is a pattern for passing through the gap between obstacles, while Bypass mode is a pattern for making a detour around obstacles safely. With these two modes, we propose an efficient obstacle avoidance method based on the Expanded Guide Circle (EGC) method with selective decision-making. The simulation and experiment results show the validity of the proposed method.

Method for surmounting an obstacle by a robot vehicle

NASA Technical Reports Server (NTRS)

Wilcox, Brian H. (Inventor); Ohm, Timothy R. (Inventor)

1994-01-01

Surmounting obstacles in the path of a robot vehicle is accomplished by rotating the wheel forks of the vehicle about their transverse axes with respect to the vehicle body so as to shift most of the vehicle weight onto the rear wheels, and then driving the vehicle forward so as to drive the now lightly-loaded front wheels (only) over the obstacle. Then, after the front wheels have either surmounted or completely passed the obstacle (depending upon the length of the obstacle), the forks are again rotated about their transverse axes so as to shift most of the vehicle weight onto the front wheels. Then the vehicle is again driven forward so as to drive the now lightly-loaded rear wheels over the obstacle. Once the obstacle has been completely cleared and the vehicle is again on relatively level terrain, the forks are again rotated so as to uniformly distribute the vehicle weight between the front and rear wheels.

Evacuation simulation with consideration of obstacle removal and using game theory

NASA Astrophysics Data System (ADS)

Lin, Guan-Wen; Wong, Sai-Keung

2018-06-01

In this paper, we integrate a cellular automaton model with game theory to simulate crowd evacuation from a room with consideration of obstacle removal. The room has one or more exits, one of which is blocked by obstacles. The obstacles at the exit can be removed by volunteers. We investigate the cooperative and defective behaviors of pedestrians during evacuation. The yielder game and volunteer's dilemma game are employed to resolve interpedestrian conflict. An anticipation floor field is proposed to guide the pedestrians to avoid obstacles that are being removed. We conducted experiments to determine how a variety of conditions affect overall crowd evacuation and volunteer evacuation times. The conditions were the start time of obstacle removal, number of obstacles, placement of obstacles, time spent in obstacle removal, strength of the anticipation floor field, and obstacle visibility distance. We demonstrate how reciprocity can be achieved among pedestrians and increases the efficiency of the entire evacuation process.

An Algorithm for Autonomous Formation Obstacle Avoidance

NASA Astrophysics Data System (ADS)

Cruz, Yunior I.

The level of human interaction with Unmanned Aerial Systems varies greatly from remotely piloted aircraft to fully autonomous systems. In the latter end of the spectrum, the challenge lies in designing effective algorithms to dictate the behavior of the autonomous agents. A swarm of autonomous Unmanned Aerial Vehicles requires collision avoidance and formation flight algorithms to negotiate environmental challenges it may encounter during the execution of its mission, which may include obstacles and chokepoints. In this work, a simple algorithm is developed to allow a formation of autonomous vehicles to perform point to point navigation while avoiding obstacles and navigating through chokepoints. Emphasis is placed on maintaining formation structures. Rather than breaking formation and individually navigating around the obstacle or through the chokepoint, vehicles are required to assemble into appropriately sized/shaped sub-formations, bifurcate around the obstacle or negotiate the chokepoint, and reassemble into the original formation at the far side of the obstruction. The algorithm receives vehicle and environmental properties as inputs and outputs trajectories for each vehicle from start to the desired ending location. Simulation results show that the algorithm safely routes all vehicles past the obstruction while adhering to the aforementioned requirements. The formation adapts and successfully negotiates the obstacles and chokepoints in its path while maintaining proper vehicle separation.

Functional Mobility Performance and Balance Confidence in Older Adults after Sensorimotor Adaptation Training

NASA Technical Reports Server (NTRS)

Buccello-Stout, Regina R.; Cromwell, Ronita L.; Bloomberg, Jacob J.; Weaver, G. D.

2010-01-01

Research indicates a main contributor of injury in older adults is from falling. The decline in sensory systems limits information needed to successfully maneuver through the environment. The objective of this study was to determine if prolonged exposure to the realignment of perceptual-motor systems increases adaptability of balance, and if balance confidence improves after training. A total of 16 older adults between ages 65-85 were randomized to a control group (walking on a treadmill while viewing a static visual scene) and an experimental group (walking on a treadmill while viewing a rotating visual scene). Prior to visual exposure, participants completed six trials of walking through a soft foamed obstacle course. Participants came in twice a week for 4 weeks to complete training of walking on a treadmill and viewing the visual scene for 20 minutes each session. Participants completed the obstacle course after training and four weeks later. Average time, penalty, and Activity Balance Confidence Scale scores were computed for both groups across testing times. The older adults who trained, significantly improved their time through the obstacle course F (2, 28) = 9.41, p < 0.05, as well as reduced their penalty scores F (2, 28) = 21.03, p < 0.05, compared to those who did not train. There was no difference in balance confidence scores between groups across testing times F (2, 28) = 0.503, p > 0.05. Although the training group improved mobility through the obstacle course, there were no differences between the groups in balance confidence.

Aerodynamic Characteristics of High Speed Trains under Cross Wind Conditions

NASA Astrophysics Data System (ADS)

Chen, W.; Wu, S. P.; Zhang, Y.

2011-09-01

Numerical simulation for the two models in cross-wind was carried out in this paper. The three-dimensional compressible Reynolds-averaged Navier-Stokes equations(RANS), combined with the standard k-ɛ turbulence model, were solved on multi-block hybrid grids by second order upwind finite volume technique. The impact of fairing on aerodynamic characteristics of the train models was analyzed. It is shown that, the flow separates on the fairing and a strong vortex is generated, the pressure on the upper middle car decreases dramatically, which leads to a large lift force. The fairing changes the basic patterns around the trains. In addition, formulas of the coefficient of aerodynamic force at small yaw angles up to 24° were expressed.

Prefrontal cortex activation during obstacle negotiation: What's the effect size and timing?

PubMed

Maidan, Inbal; Shustak, Shiran; Sharon, Topaz; Bernad-Elazari, Hagar; Geffen, Nimrod; Giladi, Nir; Hausdorff, Jeffrey M; Mirelman, Anat

2018-04-01

Obstacle negotiation is a daily activity that requires the integration of sensorimotor and cognitive information. Recent studies provide evidence for the important role of prefrontal cortex during obstacle negotiation. We aimed to explore the effects of obstacle height and available response time on prefrontal activation. Twenty healthy young adults (age: 30.1 ± 1.0 years; 50% women) walked in an obstacle course while negotiating anticipated and unanticipated obstacles at heights of 50 mm and 100 mm. Prefrontal activation was measured using a functional near-infrared spectroscopy system. Kinect cameras measured the obstacle negotiation strategy. Prefrontal activation was defined based on mean level of HbO 2 before, during and after obstacle negotiation and the HbO 2 slope from gait initiation and throughout the task. Changes between types of obstacles were assessed using linear-mix models and partial correlation analyses evaluated the relationship between prefrontal activation and the distance between the feet as the subjects traversed the obstacles. Different obstacle heights showed similar changes in prefrontal activation measures (p > 0.210). However, during unanticipated obstacles, the slope of the HbO 2 response was steeper (p = 0.048), as compared to anticipated obstacles. These changes in prefrontal activation during negotiation of unanticipated obstacles were correlated with greater distance of the leading foot after the obstacles (r = 0.831, p = 0.041). These findings are the first to show that the pattern of prefrontal activation depends on the nature of the obstacle. More specifically, during unanticipated obstacles the recruitment of the prefrontal cortex is faster and greater than during negotiating anticipated obstacles. These results provide evidence of the important role of the prefrontal cortex and the ability of healthy young adults to tailor the activation pattern to different types of obstacles. Copyright © 2018

Cooperative breakups induced by drop-to-drop interactions in one-dimensional flows of drops against micro-obstacles.

PubMed

Schmit, Alexandre; Salkin, Louis; Courbin, Laurent; Panizza, Pascal

2015-03-28

Depending on the capillary number at play and the parameters of the flow geometry, a drop may or may not break when colliding with an obstacle in a microdevice. Modeling the flow of one-dimensional trains of monodisperse drops impacting a micro-obstacle, we show numerically that complex dynamics may arise through drop-to-drop hydrodynamic interactions: we observe sequences of breakup events in which the size of the daughter drops created upon breaking mother ones becomes a periodic function of time. We demonstrate the existence of numerous bifurcations between periodic breakup regimes and we establish diagrams mapping the possible breakup dynamics as a function of the governing (physicochemical, hydrodynamic, and geometric) parameters. Microfluidic experiments validate our model as they concur very well with predictions.

The International Research Training Group (GRK532): Practicing Cross-Border Postgraduate Education

ERIC Educational Resources Information Center

Ehses, Markus; Veith, Michael

2009-01-01

In 1999, the International Research Training Group "GRK532" was founded as a pilot project for cross-border European postgraduate education along the German/French/Luxembourg borders. The project consists of an interdisciplinary research programme on synthesis, isolation and characterization of new materials accompanied by an ambitious…

Assertiveness Training and Christian Values.

ERIC Educational Resources Information Center

Bolsinger, Scot A.; McMinn, Mark R.

1989-01-01

Studies exploring the relationship between religious values and assertiveness are reviewed. Ideological obstacles in assertion training with religious clients are considered, and appropriate therapeutic strategies suggested. Emphasizes importance of presenting rationale for treatment and understanding client's value system. (Author/TE)

DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field.

PubMed

Christiansen, Peter; Nielsen, Lars N; Steen, Kim A; Jørgensen, Rasmus N; Karstoft, Henrik

2016-11-11

Convolutional neural network (CNN)-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation) algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including "Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks" (RCNN). In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45-90 m) than RCNN. RCNN has a similar performance at a short range (0-30 m). However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms =) a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit).

DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field

PubMed Central

Christiansen, Peter; Nielsen, Lars N.; Steen, Kim A.; Jørgensen, Rasmus N.; Karstoft, Henrik

2016-01-01

Convolutional neural network (CNN)-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation) algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including “Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks” (RCNN). In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45–90 m) than RCNN. RCNN has a similar performance at a short range (0–30 m). However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms =) a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit). PMID:27845717

Student with Asperger's Overcomes Obstacles: Devon's Journey to Independence

ERIC Educational Resources Information Center

Williams, Sarah Blackwelder

2010-01-01

Devon is a bright, engaging 22-year-old with a proud sense of accomplishment. He believes that while people encounter obstacles during their lives, these obstacles can be overcome with motivation and perseverance. Devon says people simply need to identify what they value, set goals and move beyond the obstacles. Devon has been faced with multiple…

Cross-Cultural Training for Business: Current State of the Art and Bibliography.

ERIC Educational Resources Information Center

Bush-Bacelis, Jean

A review of current research and research needs in cross-cultural training for business and a bibliography are presented. Future research should look at the world market that exists beyond traditional countries engaging in international trade. Business opportunities are available elsewhere, but American businessmen are ill-prepared to take…

Cross-cultural training of general practitioner registrars: how does it happen?

PubMed

Watt, Kelly; Abbott, Penny; Reath, Jenny

2016-01-01

An equitable multicultural society requires general practitioners (GPs) to be proficient in providing health care to patients from diverse backgrounds. GPs are required to have a certain attitudes, knowledge and skills known as cultural competence. Given its importance to registrar training, the aim of this study was to explore ways in which GP registrars are currently developing cultural competence. This study employed a survey design for GP registrars in Western Sydney. Training approaches to cultural competence that are relevant to the Australian General Practice setting include exposure to diversity, attitudes, knowledge and skills development. The 43 GP registrar respondents in Western Sydney are exposed to a culturally diverse patient load during training. Registrars report a variety of teachings related to cross-cultural training, but there is little consistency, with the most common approach entailing listening to patients' personal stories. Exposure to cultural diversity appears to be an important way in which cultural competency is developed. However, guidance and facilitation of skills development throughout this exposure is required and currently may occur opportunistically rather than consistently.

Simulation of Molecular Transport in Systems Containing Mobile Obstacles.

PubMed

Polanowski, Piotr; Sikorski, Andrzej

2016-08-04

In this paper, we investigate the movement of molecules in crowded environments with obstacles undergoing Brownian motion by means of extensive Monte Carlo simulations. Our investigations were performed using the dynamic lattice liquid model, which was based on the cooperative movement concept and allowed to mimic systems at high densities where the motion of all elements (obstacles as well as moving particles) were highly correlated. The crowded environments are modeled on a two-dimensional triangular lattice containing obstacles (particles whose mobility was significantly reduced) moving by a Brownian motion. The subdiffusive motion of both elements in the system was analyzed. It was shown that the percolation transition does not exist in such systems in spite of the cooperative character of the particles' motion. The reduction of the obstacle mobility leads to the longer caging of liquid particles by mobile obstacles.

Diffusion amid random overlapping obstacles: Similarities, invariants, approximations

PubMed Central

Novak, Igor L.; Gao, Fei; Kraikivski, Pavel; Slepchenko, Boris M.

2011-01-01

Efficient and accurate numerical techniques are used to examine similarities of effective diffusion in a void between random overlapping obstacles: essential invariance of effective diffusion coefficients (Deff) with respect to obstacle shapes and applicability of a two-parameter power law over nearly entire range of excluded volume fractions (ϕ), except for a small vicinity of a percolation threshold. It is shown that while neither of the properties is exact, deviations from them are remarkably small. This allows for quick estimation of void percolation thresholds and approximate reconstruction of Deff (ϕ) for obstacles of any given shape. In 3D, the similarities of effective diffusion yield a simple multiplication “rule” that provides a fast means of estimating Deff for a mixture of overlapping obstacles of different shapes with comparable sizes. PMID:21513372

Self-Reported Obstacles to Regular Dental Care among Information Technology Professionals.

PubMed

Reddy, L Swetha; Doshi, Dolar; Reddy, B Srikanth; Kulkarni, Suhas; Reddy, M Padma; Satyanarayana, D; Baldava, Pavan

2016-10-01

Good oral health is important for an individual as well as social well-being. Occupational stress and work exhaustion in Information Technology (IT) professionals may influence the oral health and oral health related quality of life. To assess and compare self-reported obstacles for regular dental care and dental visits among IT professionals based on age, gender, dental insurance and working days per week. A cross-sectional study was conducted among 1,017 IT professionals to assess the self-reported obstacles to regular oral health care in Hyderabad city, Telangana, India. The Dental Rejection of Innovation Scale (DRI-S) was employed in this study. Comparison between means of DRI-S based on variables was done using t-test and ANOVA. The association between variables and DRI-S was determined using Chi-square test. A total of 1017 participants comprising of 574 (56%) males and 443 (44%) females participated in the study. As age increased, a significant increase in mean DRI-S scores was seen for total and individual domains except for the "Situational" domain wherein higher mean score (9.42±2.5; p=0.0006) was observed among 30-39 years age group. Even though females reported higher mean scores for total and individual domains when compared to males, nevertheless significant difference was seen only for total (p=0.03) and "Lack of Knowledge" (p=0.001) domain. Self-reported obstacles to regular dental care was more with increasing age, increased number of working days per week, irregular dental visits and absence of dental insurance facility.

Obstacles to engaging in young driver licensing: Perspectives of parents.

PubMed

Naz, Sehana; Scott-Parker, Bridie

2017-02-01

Young novice drivers remain at greater risk of injury and death despite a wealth of interventions including graduated driver licensing (GDL) programs. The key to implementing safer practices inherent in GDL appears to lie with optimising the role of parents. This qualitative research explored the parent's perspectives of obstacles to engaging in the driver licensing process within a GDL program. Parents also shared advice on what they found helpful, and where relevant, recommended changes in the process to enable safer practices for young drivers. Twenty-three parents (aged 35-60 years, M=49.52, SD=8.01, 11 males) participated in semi-structured interviews regarding licensing experiences with their young driver children. The young drivers included learner (n=11), provisional (restricted/intermediate) (n=9) and open (unrestricted/full) licence drivers (n=3), ranging from 16 to 24 years (M=18.04, SD=2.21, 13 males). Content analysis revealed that most obstacles were encountered at the learner licensing phase, with the parent-reported difficult temperament of the learner driver the most prominent. Unsurprisingly, advice to other parents to be patient and remain calm featured heavily during the same phase. Anxiety from not having control of the vehicle was another obstacle at the learner phase, translating to anxieties for child safety in the early stages of provisional driving. Recommendations for the current GDL included more rigorous road rule testing, with general support for the program, professional driver training at learner and provisional stages facilitated parental engagement through the licensing phases. The findings overwhelmingly suggest a need for parents to be educated regarding their importance in, and of, the driver licensing process, and the efficacy of their instruction, content and practices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sensor-based balance training with motion feedback in people with mild cognitive impairment.

PubMed

Schwenk, Michael; Sabbagh, Marwan; Lin, Ivy; Morgan, Pharah; Grewal, Gurtej S; Mohler, Jane; Coon, David W; Najafi, Bijan

2016-01-01

Some individuals with mild cognitive impairment (MCI) experience not only cognitive deficits but also a decline in motor function, including postural balance. This pilot study sought to estimate the feasibility, user experience, and effects of a novel sensor-based balance training program. Patients with amnestic MCI (mean age 78.2 yr) were randomized to an intervention group (IG, n = 12) or control group (CG, n = 10). The IG underwent balance training (4 wk, twice a week) that included weight shifting and virtual obstacle crossing. Real-time visual/audio lower-limb motion feedback was provided from wearable sensors. The CG received no training. User experience was measured by a questionnaire. Postintervention effects on balance (center of mass sway during standing with eyes open [EO] and eyes closed), gait (speed, variability), cognition, and fear of falling were measured. Eleven participants (92%) completed the training and expressed fun, safety, and helpfulness of sensor feedback. Sway (EO, p = 0.04) and fear of falling (p = 0.02) were reduced in the IG compared to the CG. Changes in other measures were nonsignificant. Results suggest that the sensor-based training paradigm is well accepted in the target population and beneficial for improving postural control. Future studies should evaluate the added value of the sensor-based training compared to traditional training.

Overcoming obstacles to behavior change in diabetes self-management.

PubMed

Hall, Rosemary F; Joseph, Dayle Hunt; Schwartz-Barcott, Donna

2003-01-01

This study describes how 5 individuals with type 2 diabetes overcame obstacles that interfered with maintaining behavior changes in diet, exercise, and self-monitoring of blood glucose (SMBG). In-depth interviews provided the framework for this descriptive study. During audiotaped, face-to-face, follow-up structured and unstructured interviews, the participants shared their experiences about obstacles encountered and strategies used to overcome them. Each case was examined independently, and all cases were then compared with each other. Obstacles that interfered with maintaining a diet plan were hunger, planned and unplanned meal events, and the desire for new foods. Physical illness and unexpected life events were obstacles to maintaining an exercise and SMBG plan. Health professionals who assist patients who are beginning behavior change or having difficult maintaining changes need to have an understanding of the various obstacles and how patients can maintain behavior changes over time.

Bridging the Divide: Developing the Institutional Structures That Most Effectively Deliver Cross-Sectoral Education and Training.

ERIC Educational Resources Information Center

Wheelahan, Leesa

Issues in developing the institutional structures to deliver cross-sectoral education and training were examined in a study of five Australian single-sector higher education institutions with various institutional arrangements with the vocational education and training (VET) sector and five dual-sector universities. Data were collected from the…

Obstacle avoidance handling and mixed integer predictive control for space robots

NASA Astrophysics Data System (ADS)

Zong, Lijun; Luo, Jianjun; Wang, Mingming; Yuan, Jianping

2018-04-01

This paper presents a novel obstacle avoidance constraint and a mixed integer predictive control (MIPC) method for space robots avoiding obstacles and satisfying physical limits during performing tasks. Firstly, a novel kind of obstacle avoidance constraint of space robots, which needs the assumption that the manipulator links and the obstacles can be represented by convex bodies, is proposed by limiting the relative velocity between two closest points which are on the manipulator and the obstacle, respectively. Furthermore, the logical variables are introduced into the obstacle avoidance constraint, which have realized the constraint form is automatically changed to satisfy different obstacle avoidance requirements in different distance intervals between the space robot and the obstacle. Afterwards, the obstacle avoidance constraint and other system physical limits, such as joint angle ranges, the amplitude boundaries of joint velocities and joint torques, are described as inequality constraints of a quadratic programming (QP) problem by using the model predictive control (MPC) method. To guarantee the feasibility of the obtained multi-constraint QP problem, the constraints are treated as soft constraints and assigned levels of priority based on the propositional logic theory, which can realize that the constraints with lower priorities are always firstly violated to recover the feasibility of the QP problem. Since the logical variables have been introduced, the optimization problem including obstacle avoidance and system physical limits as prioritized inequality constraints is termed as MIPC method of space robots, and its computational complexity as well as possible strategies for reducing calculation amount are analyzed. Simulations of the space robot unfolding its manipulator and tracking the end-effector's desired trajectories with the existence of obstacles and physical limits are presented to demonstrate the effectiveness of the proposed obstacle avoidance

An enhanced obstacle avoiding system for AUV`s

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conte, G.; Zanoli, S.M.

1994-12-31

This paper concerns the development of a sonar-based navigation and guidance system for underwater, unmanned vehicles. In particular, the authors describe and discuss an obstacle avoidance procedure that is capable of dealing with situations involving several obstacles. The main features of the system are the use of a Kalman filter, both for estimating data and for predicting the evolution of the observed scene, and the possibility of working at different levels of data abstraction. The system has shown satisfactory performances in dealing with moving obstacles in general situations.

FieldSAFE: Dataset for Obstacle Detection in Agriculture.

PubMed

Kragh, Mikkel Fly; Christiansen, Peter; Laursen, Morten Stigaard; Larsen, Morten; Steen, Kim Arild; Green, Ole; Karstoft, Henrik; Jørgensen, Rasmus Nyholm

2017-11-09

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal camera, web camera, 360 ∘ camera, LiDAR and radar, while precise localization is available from fused IMU and GNSS. Both static and moving obstacles are present, including humans, mannequin dolls, rocks, barrels, buildings, vehicles and vegetation. All obstacles have ground truth object labels and geographic coordinates.

FieldSAFE: Dataset for Obstacle Detection in Agriculture

PubMed Central

Christiansen, Peter; Larsen, Morten; Steen, Kim Arild; Green, Ole; Karstoft, Henrik

2017-01-01

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal camera, web camera, 360∘ camera, LiDAR and radar, while precise localization is available from fused IMU and GNSS. Both static and moving obstacles are present, including humans, mannequin dolls, rocks, barrels, buildings, vehicles and vegetation. All obstacles have ground truth object labels and geographic coordinates. PMID:29120383

Motion Among Random Obstacles on a Hyperbolic Space

NASA Astrophysics Data System (ADS)

Orsingher, Enzo; Ricciuti, Costantino; Sisti, Francesco

2016-02-01

We consider the motion of a particle along the geodesic lines of the Poincaré half-plane. The particle is specularly reflected when it hits randomly-distributed obstacles that are assumed to be motionless. This is the hyperbolic version of the well-known Lorentz Process studied in the Euclidean context. We analyse the limit in which the density of the obstacles increases to infinity and the size of each obstacle vanishes: under a suitable scaling, we prove that our process converges to a Markovian process, namely a random flight on the hyperbolic manifold.

Understanding Attrition in UK Maritime Education and Training

ERIC Educational Resources Information Center

Gekara, Victor

2009-01-01

The shipping industry worldwide is experiencing a shortage of trained and qualified officers to operate a rapidly expanding global merchant fleet. High cadet wastage in Maritime Education and Training (MET) institutions is an obstacle to skills replenishment in the UK. This paper examines the specificity of MET programmes with regard to the…

Extracurricular participation in research and audit by medical students: opportunities, obstacles, motivation and outcomes.

PubMed

Nikkar-Esfahani, Ali; Jamjoom, Aimun A B; Fitzgerald, J Edward F

2012-01-01

Medical students should learn to critically evaluate research to inform future evidence-based practice. Participation in research and audit at medical school can help develop these skills whilst prompting interest in academic pursuits. We investigate medical student attitudes and participation in extracurricular research and audit focusing on their opportunities, obstacles, motivation and outcomes. A 60-item questionnaire was distributed to final-year medical students graduating from the University of Nottingham Medical School in the United Kingdom. A total of 238 questionnaires were returned (response rate 75%). Of these, 86% felt research or audit experience was useful for medical students. The main driver for involvement was curriculum vitae (CV) improvement (51%). Male students and those involved in extracurricular research were more likely to agree that this experience should influence selection into training programmes (p = 0.017, p = 0.0036). Overall, 91 respondents (38%) had been involved in such activity with a mean number of projects undertaken of two (range one to four). Those interested in a surgical career were most likely to have undertaken projects (58%). Frequently cited obstacles to involvement were time constraints (74%) and a perceived lack of interest from potential supervisors (63%). Despite significant CV motivation, many are enthusiastic regarding extracurricular research opportunities but frustrated by obstacles faced. Our study suggests there is scope for providing further opportunities to participate in such activities at medical school.

Improving Intercultural Interactions. Modules for Cross-Cultural Training Programs. Multicultural Aspects of Counseling Series 3.

ERIC Educational Resources Information Center

Brislin, Richard W., Ed.; Yoshida, Tomoko, Ed.

This book contains modules for use in cross-cultural training programs. A module differs from a chapter in that it is a collection of materials that guide the reader both on the content of a defined unit of training and the method of delivery of that content. The modules are grouped into four sections, three corresponding to organizations in which…

Cross cultural training in primary mental health care consultations in Moldova - The tEACH perspective.

PubMed

Møller, Jane Ege; van Weel-Baumgarten, Evelyn

2017-09-01

This article reports experiences and challenges encountered in a cross-cultural training project in Moldova that was undertaken by tEACH, the teaching subcommittee of EACH: International Association for Communication in Healthcare, in cooperation with local and international stakeholders. As part of a major health policy reform, the aim was to equip a group of trainers with the skills to train Moldovan professionals in skills for primary mental health care, including communication skills. The project consisted of 3 weeks of training using mainly experiential teaching methods to allow participants to practice content and methods, including interactive lecturing, roleplay, feedback and video. A majority of the participants reported that they acquired key facilitation skills. They valued the opportunity to practice and receive feedback. However, some reported that there was too much focus on communication skills, which was thought to be less relevant in a Moldovan context. Furthermore our learner-centered approach was occasionally experienced as a lack of structure CONCLUSION: The tEACH expertise plays an important role in supporting trainers in cross-cultural contexts with effective communication skills methods. Teaching in a cross-cultural context is only successful through continuous dialogue with stakeholders and demands attention to cultural differences. Copyright © 2017. Published by Elsevier B.V.

A Mixed Method Case Study on Learner Engagement in e-Learning Professional Training

ERIC Educational Resources Information Center

Zhao, Jane Yanfeng

2014-01-01

Previous research showed that learners' reluctance in participating in e-Learning training is a major obstacle in achieving training objectives. This study focused on learners' e-Learning engagement in professional training in the chapter of the American Society for Training and Development (ASTD). The participants were 21 chapter members.…

Plant root and shoot dynamics during subsurface obstacle interaction

NASA Astrophysics Data System (ADS)

Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

Three-dimensional obstacle classification in laser range data

NASA Astrophysics Data System (ADS)

Armbruster, Walter; Bers, Karl-Heinz

1998-10-01

The threat of hostile surveillance and weapon systems require military aircraft to fly under extreme conditions such as low altitude, high speed, poor visibility and incomplete terrain information. The probability of collision with natural and man-made obstacles during such contour missions is high if detection capability is restricted to conventional vision aids. Forward-looking scanning laser rangefinders which are presently being flight tested and evaluated at German proving grounds, provide a possible solution, having a large field of view, high angular and range resolution, a high pulse repetition rate, and sufficient pulse energy to register returns from wires at over 500 m range (depends on the system) with a high hit-and-detect probability. Despite the efficiency of the sensor, acceptance of current obstacle warning systems by test pilots is not very high, mainly due to the systems' inadequacies in obstacle recognition and visualization. This has motivated the development and the testing of more advanced 3d-scene analysis algorithm at FGAN-FIM to replace the obstacle recognition component of current warning systems. The basic ideas are to increase the recognition probability and to reduce the false alarm rate for hard-to-extract obstacles such as wires, by using more readily recognizable objects such as terrain, poles, pylons, trees, etc. by implementing a hierarchical classification procedure to generate a parametric description of the terrain surface as well as the class, position, orientation, size and shape of all objects in the scene. The algorithms can be used for other applications such as terrain following, autonomous obstacle avoidance, and automatic target recognition.

Stepping back to see the big picture: when obstacles elicit global processing.

PubMed

Marguc, Janina; Förster, Jens; Van Kleef, Gerben A

2011-11-01

Can obstacles prompt people to look at the "big picture" and open up their minds? Do the cognitive effects of obstacles extend beyond the tasks with which they interfere? These questions were addressed in 6 studies involving both physical and nonphysical obstacles and different measures of global versus local processing styles. Perceptual scope increased after participants solved anagrams in the presence, rather than the absence, of an auditory obstacle (random words played in the background; Study 1), particularly among individuals low in volatility (i.e., those who are inclined to stay engaged and finish what they do; Study 4). It also increased immediately after participants encountered a physical obstacle while navigating a maze (Study 3A) and when compared with doing nothing (Study 3B). Conceptual scope increased after participants solved anagrams while hearing random numbers framed as an "obstacle to overcome" rather than a "distraction to ignore" (Study 2) and after participants navigated a maze with a physical obstacle, compared with a maze without a physical obstacle, but only when trait (Study 5) or state (Study 6) volatility was low. Results suggest that obstacles trigger an "if obstacle, then start global processing" response, primarily when people are inclined to stay engaged and finish ongoing activities. Implications for dealing with life's obstacles and related research are discussed.

Using Thermal Radiation in Detection of Negative Obstacles

NASA Technical Reports Server (NTRS)

Rankin, Arturo L.; Matthies, Larry H.

2009-01-01

A method of automated detection of negative obstacles (potholes, ditches, and the like) ahead of ground vehicles at night involves processing of imagery from thermal-infrared cameras aimed at the terrain ahead of the vehicles. The method is being developed as part of an overall obstacle-avoidance scheme for autonomous and semi-autonomous offroad robotic vehicles. The method could also be applied to help human drivers of cars and trucks avoid negative obstacles -- a development that may entail only modest additional cost inasmuch as some commercially available passenger cars are already equipped with infrared cameras as aids for nighttime operation.

Perceived Obstacles Faced by Diabetes Patients Attending University of Gondar Hospital, Northwest Ethiopia.

PubMed

Bhagavathula, Akshaya Srikanth; Gebreyohannes, Eyob Alemayehu; Abegaz, Tadesse Melaku; Abebe, Tamrat Befekadu

2018-01-01

Diabetes mellitus (DM) is a non-communicable, chronic, and progressive disease that can lead to serious complications and even to premature death. A closer understanding of the DM patients' specific obstacles will provide a greater clarity of the factors influencing their disease-related quality of life and coping with daily life. The study aimed to evaluate the obstacles of DM patients attending ambulatory clinic of the University of Gondar Hospital (UOGH), Northwest Ethiopia. A cross-sectional study was conducted from February to April 2017 at ambulatory clinic of the UOGH. A validated short version of the diabetic obstacle questionnaire was used. The internal reliability of the questionnaire was checked using Cronbach's alpha and was found to be 92.5%. To determine any association between each of the nine sections of the questionnaire and age, sex, residence, educational status, and DM type, a binary logistic regression was performed. The mean age of respondents was 38.69 ± 15.39 years. Compared with patients with type 1 DM, patients with type 2 DM reported poorer relationships with medical professionals (adjusted odds ratio (AOR): 2.191, p -value = 0.027) and less support from families and friends (AOR: 1.913, p -value = 0.049). Patients coming from rural areas (AOR: 2.947, p  = 0.002) and having no formal education (AOR: 2.078, p  = 0.029) also received less support from families and friends. DM patients in UOGH reported several obstacles related to patients' relationship with health professionals, lack of support from their friends, lack of knowledge about DM, and lack of motivation to exercise. Effective efforts should be initiated to improve healthier environment to educate, care and preventive services for people with DM.

Hypobaric live high-train low does not improve aerobic performance more than live low-train low in cross-country skiers.

PubMed

Robach, P; Hansen, J; Pichon, A; Meinild Lundby, A-K; Dandanell, S; Slettaløkken Falch, G; Hammarström, D; Pesta, D H; Siebenmann, C; Keiser, S; Kérivel, P; Whist, J E; Rønnestad, B R; Lundby, C

2018-06-01

Live high-train low (LHTL) using hypobaric hypoxia was previously found to improve sea-level endurance performance in well-trained individuals; however, confirmatory controlled data in athletes are lacking. Here, we test the hypothesis that natural-altitude LHTL improves aerobic performance in cross-country skiers, in conjunction with expansion of total hemoglobin mass (Hb mass , carbon monoxide rebreathing technique) promoted by accelerated erythropoiesis. Following duplicate baseline measurements at sea level over the course of 2 weeks, nineteen Norwegian cross-country skiers (three women, sixteen men, age 20 ± 2 year, maximal oxygen uptake (VO 2 max) 69 ± 5 mL/min/kg) were assigned to 26 consecutive nights spent at either low (1035 m, control, n = 8) or moderate altitude (2207 m, daily exposure 16.7 ± 0.5 hours, LHTL, n = 11). All athletes trained together daily at a common location ranging from 550 to 1500 m (21.2% of training time at 550 m, 44.2% at 550-800 m, 16.6% at 800-1100 m, 18.0% at 1100-1500 m). Three test sessions at sea level were performed over the first 3 weeks after intervention. Despite the demonstration of nocturnal hypoxemia at moderate altitude (pulse oximetry), LHTL had no specific effect on serum erythropoietin, reticulocytes, Hb mass , VO 2 max, or 3000-m running performance. Also, LHTL had no specific effect on (a) running economy (VO 2 assessed during steady-state submaximal exercise), (b) respiratory capacities or efficiency of the skeletal muscle (biopsy), and (c) diffusing capacity of the lung. This study, showing similar physiological responses and performance improvements in the two groups following intervention, suggests that in young cross-country skiers, improvements in sea-level aerobic performance associated with LHTL may not be due to moderate-altitude acclimatization. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Determinants, obstacles, sources and cooperation to innovation in Portuguese firms, using community innovation survey

NASA Astrophysics Data System (ADS)

Correia, Aldina; Braga, Alexandra; Braga, Vitor

2017-06-01

Innovation is a topic of interest for the management researchers, confirmed by the creation of a Community Innovation Survey, which is an harmonised tool designed to provide information about Innovation in European Union enterprises. In this study, we use factorial analysis to identify the determinants and obstacles to innovation in Portuguese firms. The sources of innovation and cooperation to innovation are also analysed, using crossed information. For the determinants of innovation six factors were identified: Production costs and impacts to health and environment, Process and product innovation, Organizational innovation, Institutional sources of information, Others sources of information and Market sources of information. Obstacles to innovation were clustered into three groups: Knowledge and market factors, Cost factors and Reasons not to innovate. The main sources of innovation identified, in this study, are Suppliers and Clients, located in Portugal and in Europe. Cooperation partners are also majority Clients and Suppliers, in addition to other enterprises in the same group.

Joint Doctrine for Barriers, Obstacles, and Mine Warfare

DTIC Science & Technology

1999-02-24

of explosives. Typical tactical examples are barbed wire obstacles and tank ditches. Operational and strategic barriers and obstacles may also be...total of 10 ocean minesweepers, 9 amphibious ships, 6 fleet tugs, 3 salvage ships, and 19 destroyers. Twenty-four CH-53D Sea Stallions from Marine

How Obstacles Perturb Population Fronts and Alter Their Genetic Structure.

PubMed

Möbius, Wolfram; Murray, Andrew W; Nelson, David R

2015-12-01

As populations spread into new territory, environmental heterogeneities can shape the population front and genetic composition. We focus here on the effects of an important building block of heterogeneous environments, isolated obstacles. With a combination of experiments, theory, and simulation, we show how isolated obstacles both create long-lived distortions of the front shape and amplify the effect of genetic drift. A system of bacteriophage T7 spreading on a spatially heterogeneous Escherichia coli lawn serves as an experimental model system to study population expansions. Using an inkjet printer, we create well-defined replicates of the lawn and quantitatively study the population expansion of phage T7. The transient perturbations of the population front found in the experiments are well described by a model in which the front moves with constant speed. Independent of the precise details of the expansion, we show that obstacles create a kink in the front that persists over large distances and is insensitive to the details of the obstacle's shape. The small deviations between experimental findings and the predictions of the constant speed model can be understood with a more general reaction-diffusion model, which reduces to the constant speed model when the obstacle size is large compared to the front width. Using this framework, we demonstrate that frontier genotypes just grazing the side of an isolated obstacle increase in abundance, a phenomenon we call 'geometry-enhanced genetic drift', complementary to the founder effect associated with spatial bottlenecks. Bacterial range expansions around nutrient-poor barriers and stochastic simulations confirm this prediction. The effect of the obstacle on the genealogy of individuals at the front is characterized by simulations and rationalized using the constant speed model. Lastly, we consider the effect of two obstacles on front shape and genetic composition of the population illuminating the effects expected from

A comparative study on managers', staffs' and clients' viewpoints about organizational and structural obstacles in family planning counseling in health-care centers in Isfahan in 2012.

PubMed

Taheri, Safoura; Ehsanpour, Soheila; Kohan, Shahnaz

2014-03-01

Organizational and structural obstacles are a group of major obstacles in achievement of appropriate family planning counseling. Detection of these obstacles from the viewpoint of managers, staffs and clients who are key members in health services providing system is a major step toward appropriate planning to modify or delete this group of obstacles. The present study was conducted with the goal of comparing managers', staffs' and clients' viewpoints about organizational and structural obstacles in family planning counseling in health-care centers in Isfahan in 2012. This is a cross-sectional one-step three-group comparative descriptive study conducted on 295 subjects including 59 managers, 110 staffs and 126 clients in medical health-care centers in Isfahan in 2012. Managers and the staffs were selected by census sampling and the clients were recruited through convenient random sampling. The date collection tool was a researcher made questionnaire, which was designed in two sections of fertility and personal characteristics and viewpoint measurement. Descriptive and inferential statistical test were used to analyze the data. The obtained results showed no significant difference between mean scores of viewpoints in three groups of managers, staffs and clients concerning organizational and structural obstacles in family planning counseling (P = 0.677). In addition, most of the managers, staffs and clients reported organizational and structural obstacles as the obstacles in the process of family planning in moderate level. The results showed the necessity of health services managers' planning to modify or delete organizational and structural obstacles especially the agreed obstacles from the viewpoint of managers, staffs and clients.

Research on UAV Intelligent Obstacle Avoidance Technology During Inspection of Transmission Line

NASA Astrophysics Data System (ADS)

Wei, Chuanhu; Zhang, Fei; Yin, Chaoyuan; Liu, Yue; Liu, Liang; Li, Zongyu; Wang, Wanguo

Autonomous obstacle avoidance of unmanned aerial vehicle (hereinafter referred to as UAV) in electric power line inspection process has important significance for operation safety and economy for UAV intelligent inspection system of transmission line as main content of UAV intelligent inspection system on transmission line. In the paper, principles of UAV inspection obstacle avoidance technology of transmission line are introduced. UAV inspection obstacle avoidance technology based on particle swarm global optimization algorithm is proposed after common obstacle avoidance technologies are studied. Stimulation comparison is implemented with traditional UAV inspection obstacle avoidance technology which adopts artificial potential field method. Results show that UAV inspection strategy of particle swarm optimization algorithm, adopted in the paper, is prominently better than UAV inspection strategy of artificial potential field method in the aspects of obstacle avoidance effect and the ability of returning to preset inspection track after passing through the obstacle. An effective method is provided for UAV inspection obstacle avoidance of transmission line.

Collective strategy for obstacle navigation during cooperative transport by ants.

PubMed

McCreery, Helen F; Dix, Zachary A; Breed, Michael D; Nagpal, Radhika

2016-11-01

Group cohesion and consensus have primarily been studied in the context of discrete decisions, but some group tasks require making serial decisions that build on one another. We examine such collective problem solving by studying obstacle navigation during cooperative transport in ants. In cooperative transport, ants work together to move a large object back to their nest. We blocked cooperative transport groups of Paratrechina longicornis with obstacles of varying complexity, analyzing groups' trajectories to infer what kind of strategy the ants employed. Simple strategies require little information, but more challenging, robust strategies succeed with a wider range of obstacles. We found that transport groups use a stochastic strategy that leads to efficient navigation around simple obstacles, and still succeeds at difficult obstacles. While groups navigating obstacles preferentially move directly toward the nest, they change their behavior over time; the longer the ants are obstructed, the more likely they are to move away from the nest. This increases the chance of finding a path around the obstacle. Groups rapidly changed directions and rarely stalled during navigation, indicating that these ants maintain consensus even when the nest direction is blocked. Although some decisions were aided by the arrival of new ants, at many key points, direction changes were initiated within the group, with no apparent external cause. This ant species is highly effective at navigating complex environments, and implements a flexible strategy that works for both simple and more complex obstacles. © 2016. Published by The Company of Biologists Ltd.

Mistakes or deliberate violations? A study into the origins of rule breaking at pedestrian train crossings.

PubMed

Freeman, James; Rakotonirainy, Andry

2015-04-01

Train pedestrian collisions are the most likely to result in severe injuries and fatalities when compared to other types of rail crossing accidents. However, there is currently scant research that has examined the origins of pedestrians' rule breaking at level crossings. As a result, this study examined the origins of pedestrians' rule breaking behaviour at crossings, with particular emphasis directed towards examining the factors associated with making errors versus deliberation violations. A total of 636 individuals volunteered to participate in the study and completed either an online or paper version of the questionnaire. Quantitative analysis of the data revealed that knowledge regarding crossing rules was high, although up to 18% of level crossing users were either unsure or did not know (in some circumstances) when it was legal to cross at a level crossing. Furthermore, 156 participants (24.52%) reported having intentionally violated the rules at level crossings and 3.46% (n=22) of the sample had previously made a mistake at a crossing. In regards to rule violators, males (particularly minors) were more likely to report breaking rules, and the most frequent occurrence was after the train had passed rather than before it arrives. Regression analysis revealed that males who frequently use pedestrian crossings and report higher sensation seeking traits are most likely to break the rules. This research provides evidence that pedestrians are more likely to deliberately violate rules (rather than make errors) at crossings and it illuminates high risk groups. This paper will further outline the study findings in regards to the development of countermeasures as well as provide direction for future research efforts in this area. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of form of obstacle on speed of crowd evacuation

NASA Astrophysics Data System (ADS)

Yano, Ryosuke

2018-03-01

This paper investigates the effect of the form of an obstacle on the time that a crowd takes to evacuate a room, using a toy model. Pedestrians are modeled as active soft matter moving toward a point with intended velocities. An obstacle is placed in front of the exit, and it has one of four shapes: a cylindrical column, a triangular prism, a quadratic prism, or a diamond prism. Numerical results indicate that the evacuation-completion time depends on the shape of the obstacle. Obstacles with a circular cylinder (C.C.) shape yield the shortest evacuation-completion time in the proposed model.

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions.

PubMed

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or "initial center-of-mass set") on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions

PubMed Central

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A.; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or “initial center-of-mass set”) on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot

Use of VR Technology and Passive Haptics for MANPADS Training System

DTIC Science & Technology

2017-09-01

this setup also does not offer a variety of challenging scenarios needed for good training as the aircraft are mostly flying in landing or take-off... customized high-fidelity immersive training facilities are limited. Moreover, low trainee throughput from such high-end facilities is an ongoing obstacle...opportunities allow few operators to fire during live exercises. Simulation training is effective, but customized high-fidelity immersive training

[Development of child mental health services in Lithuania: achievements and obstacles].

PubMed

Pūras, Dainius

2002-01-01

In 1990, political, economic and social changes in Lithuania introduced the possibility to develop for the first time in nations's history an effective and modern system of child mental health services. During the period between 1990 and 1995 a new model of services was developed in the Department of Social pediatrics and child psychiatry of Vilnius University. The model included development of child and adolescent psychiatric services, as well as early intervention services for infants and preschool children with developmental disabilities. The emphasis, following recommendations of WHO and existing international standards, was made on deinstitutionalization and development of family-oriented and community-based services, which have been ignored by previous system. In the first half of 90's of 20th century, new training programs for professionals were introduced, more than 50 methods of assessment, treatment and rehabilitation, new for Lithuanian clinical practice, were implemented, and a new model of services, including primary, secondary and tertiary level of prevention, was introduced in demonstration sites. However, during next phase of development, in 1997-2001, serious obstacles for replicating new approaches across the country, have been identified, which threatened successful implementation of the new model of services into everyday clinical practice. Analysis of obstacles, which are blocking development of new approaches in the field of child mental health, is presented in the article. The main obstacles, identified during analysis of socioeconomic context, planning and utilization of resources, running of the system of services and evaluation of outcomes, are as follows: lack of intersectorial cooperation between health, education and social welfare systems; strong tradition of discrimination of psychosocial interventions in funding schemes of health services; societal attitudes, which tend to discriminate and stigmatize marginal groups, including

The Power of Cross-Disciplinary Teams for Developing First Responder Training in TBI

ERIC Educational Resources Information Center

Shackelford, Jo L.; Cappiccie, Amy

2016-01-01

Misunderstanding of the symptoms of traumatic brain injury (TBI) often leaves first responders ill-equipped to handle encounters involving subjects with brain injury. This paper details a cross-disciplinary project to develop and disseminate a training curriculum designed to increase first responders' knowledge of and skills with TBI survivors.…

Genograms and Family Sculpting: An Aid to Cross-Cultural Understanding in the Training of Psychology Students in South Africa.

ERIC Educational Resources Information Center

Marchetti-Mercer, Maria C.; Cleaver, Glenda

2000-01-01

Describes a specific training method developed in a family therapy course at the University of Pretoria in South Africa, where genograms and family sculpting were used to improve cross-cultural understanding among psychology masters students. Discusses the theoretical implications of the group training process for the training of psychologists in…

Laser development for optimal helicopter obstacle warning system LADAR performance

NASA Astrophysics Data System (ADS)

Yaniv, A.; Krupkin, V.; Abitbol, A.; Stern, J.; Lurie, E.; German, A.; Solomonovich, S.; Lubashitz, B.; Harel, Y.; Engart, S.; Shimoni, Y.; Hezy, S.; Biltz, S.; Kaminetsky, E.; Goldberg, A.; Chocron, J.; Zuntz, N.; Zajdman, A.

2005-04-01

Low lying obstacles present immediate danger to both military and civilian helicopters performing low-altitude flight missions. A LADAR obstacle detection system is the natural solution for enhancing helicopter safety and improving the pilot situation awareness. Elop is currently developing an advanced Surveillance and Warning Obstacle Ranging and Display (SWORD) system for the Israeli Air Force. Several key factors and new concepts have contributed to system optimization. These include an adaptive FOV, data memorization, autonomous obstacle detection and warning algorithms and the use of an agile laser transmitter. In the present work we describe the laser design and performance and discuss some of the experimental results. Our eye-safe laser is characterized by its pulse energy, repetition rate and pulse length agility. By dynamically controlling these parameters, we are able to locally optimize the system"s obstacle detection range and scan density in accordance with the helicopter instantaneous maneuver.

Influence of obstacles on bubbles rising in water-saturated sand

NASA Astrophysics Data System (ADS)

Poryles, Raphaël; Varas, Germán; Vidal, Valérie

2017-06-01

This work investigates the dynamics of air rising through a water-saturated sand confined in a Hele- Shaw cell in which a circular obstacle is trapped. The air is injected at constant flow rate through a single nozzle at the bottom center of the cell. Without obstacle, in a similar configuration, previous studies pointed out the existence of a fluidized zone generated by the central upward gas motion which entrains two granular convection rolls on its sides. Here, a circular obstacle which diameter is of the order of the central air channel width is trapped at the vertical of the injection nozzle. We analyze the influence of the obstacle location on the size of the fluidized zone and its impact on the morphology of the central air channel. Finally, we quantify the variations of the granular free surface. Two configurations with multiple obstacles are also considered.

Novel approaches to helicopter obstacle warning

NASA Astrophysics Data System (ADS)

Seidel, Christian; Samuelis, Christian; Wegner, Matthias; Münsterer, Thomas; Rumpf, Thomas; Schwartz, Ingo

2006-05-01

EADS Germany is the world market leader in commercial Helicopter Laser Radar (HELLAS) Obstacle Warning Systems. The HELLAS-Warning System has been introduced into the market in 2000, is in service at German Border Control (Bundespolizei) and Royal Thai Airforce and is successfully evaluated by the Foreign Comparative Test Program (FCT) of the USSOCOM. Currently the successor system HELLAS-Awareness is in development. It will have extended sensor performance, enhanced realtime data processing capabilities and advanced HMI features. We will give an outline of the new sensor unit concerning detection technology and helicopter integration aspects. The system provides a widespread field of view with additional dynamic line of sight steering and a large detection range in combination with a high frame rate of 3Hz. The workflow of the data processing will be presented with focus on novel filter techniques and obstacle classification methods. As commonly known the former are indispensable due to unavoidable statistical measuring errors and solarisation. The amount of information in the filtered raw data is further reduced by ground segmentation. The remaining raised objects are extracted and classified in several stages into different obstacle classes. We will show the prioritization function which orders the obstacles concerning to their threat potential to the helicopter taking into account the actual flight dynamics. The priority of an object determines the display and provision of warnings to the pilot. Possible HMI representation includes video or FLIR overlay on multifunction displays, audio warnings and visualization of information on helmet mounted displays and digital maps. Different concepts will be presented.

Laser radar system for obstacle avoidance

NASA Astrophysics Data System (ADS)

Bers, Karlheinz; Schulz, Karl R.; Armbruster, Walter

2005-09-01

The threat of hostile surveillance and weapon systems require military aircraft to fly under extreme conditions such as low altitude, high speed, poor visibility and incomplete terrain information. The probability of collision with natural and man-made obstacles during such contour missions is high if detection capability is restricted to conventional vision aids. Forward-looking scanning laser radars which are build by the EADS company and presently being flight tested and evaluated at German proving grounds, provide a possible solution, having a large field of view, high angular and range resolution, a high pulse repetition rate, and sufficient pulse energy to register returns from objects at distances of military relevance with a high hit-and-detect probability. The development of advanced 3d-scene analysis algorithms had increased the recognition probability and reduced the false alarm rate by using more readily recognizable objects such as terrain, poles, pylons, trees, etc. to generate a parametric description of the terrain surface as well as the class, position, orientation, size and shape of all objects in the scene. The sensor system and the implemented algorithms can be used for other applications such as terrain following, autonomous obstacle avoidance, and automatic target recognition. This paper describes different 3D-imaging ladar sensors with unique system architecture but different components matched for different military application. Emphasis is laid on an obstacle warning system with a high probability of detection of thin wires, the real time processing of the measured range image data, obstacle classification und visualization.

Effect of an active another train coming warning system on pedestrian behavior at a highway-rail grade crossing

DOT National Transportation Integrated Search

2014-04-01

The Federal Railroad Administration (FRA) was interested in evaluating a type of grade crossing safety enhancement which alerts pedestrians at the crossing to the presence of a second train. The system chosen for this analysis, known as an Another Tr...

Using the socio-ecological framework to determine breastfeeding obstacles in a low-income population in Tijuana, Mexico: healthcare services.

PubMed

Bueno-Gutierrez, Diana; Chantry, Caroline

2015-03-01

In Mexico, breastfeeding rates are one of the lowest of Latin America, with 14.4% of infants under 6 months being exclusively breastfed. Previous studies indicate that lack of support from healthcare services is a serious obstacle to breastfeeding mothers in Mexico. Our objective was to identify the main obstacles to breastfeeding presented by the healthcare services in a low-income population in Tijuana, Mexico. We used a socio-ecological framework to determine factors affecting breastfeeding practices. In four low-income communities in Tijuana we conducted focus groups and interviews with mothers, fathers, grandparents, and key informants. Interview notes and focus group transcripts were then studied in-depth independently by three researchers. The primary analytic technique was constant comparison. One hundred twenty-nine subjects participated in this study: six focus groups (n=53) and 51 interviews among mothers, fathers, and grandparents, as well as 25 interviews among key informants. Main healthcare service obstacles to breastfeeding were erroneous information, lack of training and supervision, negative attitudes, miscommunication between healthcare providers (HCPs) and patients, detrimental medical practices such as giving free formula at hospitals, and the conflict of interest between the infant food industry and the HCPs. This study showed that women in low-income communities in Tijuana face multiple obstacles to breastfeeding presented by healthcare services. In order to increase breastfeeding rates, institutional and structural changes are required.

Performance and three-dimensional kinematics of bipedal lizards during obstacle negotiation.

PubMed

Olberding, Jeffrey P; McBrayer, Lance D; Higham, Timothy E

2012-01-15

Bipedal running is common among lizard species, but although the kinematics and performance of this gait have been well characterized, the advantages in biologically relevant situations are still unclear. Obstacle negotiation is a task that is ecologically relevant to many animals while moving at high speeds, such as during bipedal running, yet little is known about how obstacles impact locomotion and performance. We examined the effects of obstacle negotiation on the kinematics and performance of lizards during bipedal locomotion. We quantified three-dimensional kinematics from high-speed video (500 Hz) of six-lined racerunners (Aspidoscelis sexlineata) running on a 3 m racetrack both with and without an obstacle spanning the width of the track. The lizards did not alter their kinematics prior to contacting the obstacle. Although contact with the obstacle caused changes to the hindlimb kinematics, mean forward speed did not differ between treatments. The deviation of the vertical position of the body center of mass did not differ between treatments, suggesting that in the absence of a cost to overall performance, lizards forgo maintaining normal kinematics while negotiating obstacles in favor of a steady body center of mass height to avoid destabilizing locomotion.

Advanced Augmented White Cane with obstacle height and distance feedback.

PubMed

Pyun, Rosali; Kim, Yeongmi; Wespe, Pascal; Gassert, Roger; Schneller, Stefan

2013-06-01

The white cane is a widely used mobility aid that helps visually impaired people navigate the surroundings. While it reliably and intuitively extends the detection range of ground-level obstacles and drop-offs to about 1.2 m, it lacks the ability to detect trunk and head-level obstacles. Electronic Travel Aids (ETAs) have been proposed to overcome these limitations, but have found minimal adoption due to limitations such as low information content and low reliability thereof. Although existing ETAs extend the sensing range beyond that of the conventional white cane, most of them do not detect head-level obstacles and drop-offs, nor can they identify the vertical extent of obstacles. Furthermore, some ETAs work independent of the white cane, and thus reliable detection of surface textures and drop-offs is not provided. This paper introduces a novel ETA, the Advanced Augmented White Cane, which detects obstacles at four vertical levels and provides multi-sensory feedback. We evaluated the device in five blindfolded subjects through reaction time measurements following the detection of an obstacle, as well as through the reliability of dropoff detection. The results showed that our aid could help the user successfully detect an obstacle and identify its height, with an average reaction time of 410 msec. Drop-offs were reliably detected with an intraclass correlation > 0.95. This work is a first step towards a low-cost ETA to complement the functionality of the conventional white cane.

What shape do UK trainees want their training to be? Results of a cross-sectional study

PubMed Central

Harries, Rhiannon L; Rashid, Mustafa; Smitham, Peter; Vesey, Alex; McGregor, Richard; Scheeres, Karl; Bailey, Jon; Sohaib, Syed Mohammed Afzal; Prior, Matthew; Frost, Jonathan; Al-Deeb, Walid; Kugathasan, Gana; Gokani, Vimal J

2016-01-01

Objectives The British Government is acting on recommendations to overhaul postgraduate training to meet the needs of the changing population, to produce generalist doctors undergoing shorter broad-based training (Greenaway Review). Only 45 doctors in training were involved in the consultation process. This study aims to obtain a focused perspective on the proposed reforms by doctors in training from across specialities. Design Prospective, questionnaire-based cross-sectional study. Setting/participants Following validation, a 31-item electronic questionnaire was distributed via trainee organisations and Postgraduate Local Education and Training Board (LETB) mailing lists. Throughout the 10-week study period, the survey was publicised on several social media platforms. Results Of the 3603 demographically representative respondents, 69% knew about proposed changes. Of the respondents, 73% expressed a desire to specialise, with 54% keen to provide general emergency cover. A small proportion (12%) stated that current training pathway length is too long, although 86% felt that it is impossible to achieve independent practitioner-level proficiency in a shorter period of time than is currently required. Opinions regarding credentialing were mixed, but tended towards disagreement. The vast majority (97%) felt credentialing should not be funded by doctors in training. Respondents preferred longer placement lengths with increasing career progression. Doctors in training value early generalised training (65%), with suggestions for further improvement. Conclusions This is the first large-scale cross-specialty study regarding the Shape of Training Review. Although there are recommendations which trainees support, it is clear that one size does not fit all. Most trainees are keen to provide a specialist service on an emergency generalist background. Credentialing is a contentious issue; however, we believe removing aspects from curricula into post-Certificate of Completion of

Cross-Training Laboratory Animal Care Personnel in Physically Separate Animal Facilities at a Land-Grant Institution.

PubMed

Henze, Tonja M; Allison, Sarah O; Criley, Jennifer M; Myers, Sara J; Goodly, Lyndon J

2016-01-01

The University of Illinois at Urbana-Champaign maintains physically separated animal care facilities under centralized management by the Division of Animal Resources. As part of a land-grant institution, the animal care and use program operates several animal units in key locations for specific disciplines within the campus, all of which have the core mission to teach, conduct research, and engage in public service. Populations of research animals vary with the levels of research funding, the number of research investigators on staff, research direction, and animal availability. Accordingly, the requirement for animal care staffing in each unit may vary widely also. To best use the existing animal care staff and remain fiscally responsible, cross-training of staff was implemented to allow staff to travel from units with small animal populations to units with larger populations or short-term staffing shortages. Here we detail and describe the system we used to assess the needs for cross-training, identify the staff to train, and implement the training plan. We believe this information will assist other programs, particularly those with large or complex organization (for example, land-grant institutions) that experience similar fluctuations in animal use.

[Career satisfaction of German medical residents after four years of training].

PubMed

Römer, Farina; Ziegler, Stine; Scherer, Martin; van den Bussche, Hendrik

2017-02-01

To evaluate German residents' career satisfaction and its dependency on intrinsic and extrinsic factors after four years of postgraduate training. Gender, parental status, training conditions and specialty choice were of particular interest. Postal questionnaires were sent to medical graduates from seven different German faculties annually, starting in 2009. This paper presents cross-sectional data of domestic, working and training conditions four years after graduation. We used descriptive statistics and t-tests. In order to identify factors with an impact on career satisfaction, multiple regression analyses were calculated. Male residents who have children tended to be more satisfied with their career than residents without children. For female residents, however, having children was associated with lower career satisfaction. Those who chose training in general surgery or orthopedic surgery were less satisfied with their career progress. Residents with prolonged specialty training showed lower career satisfaction. Junior doctors who rated the quality of their residency training higher were more satisfied with their career. Those who perceived their job as particularly demanding were less satisfied. Concerning intrinsic factors, occupational self-efficacy and overall satisfaction with life were significantly associated with career satisfaction. Residents in general are quite satisfied with their career after four years of training. Opportunities to work part-time during residency as well as structured training programs should be implemented in order to overcome parenthood as a career obstacle for female residents. The quality of specialty training is particularly important for career satisfaction and has to be ensured across specialties. Copyright © 2017. Published by Elsevier GmbH.

How Obstacles Perturb Population Fronts and Alter Their Genetic Structure

PubMed Central

Möbius, Wolfram; Murray, Andrew W.; Nelson, David R.

2015-01-01

As populations spread into new territory, environmental heterogeneities can shape the population front and genetic composition. We focus here on the effects of an important building block of heterogeneous environments, isolated obstacles. With a combination of experiments, theory, and simulation, we show how isolated obstacles both create long-lived distortions of the front shape and amplify the effect of genetic drift. A system of bacteriophage T7 spreading on a spatially heterogeneous Escherichia coli lawn serves as an experimental model system to study population expansions. Using an inkjet printer, we create well-defined replicates of the lawn and quantitatively study the population expansion of phage T7. The transient perturbations of the population front found in the experiments are well described by a model in which the front moves with constant speed. Independent of the precise details of the expansion, we show that obstacles create a kink in the front that persists over large distances and is insensitive to the details of the obstacle’s shape. The small deviations between experimental findings and the predictions of the constant speed model can be understood with a more general reaction-diffusion model, which reduces to the constant speed model when the obstacle size is large compared to the front width. Using this framework, we demonstrate that frontier genotypes just grazing the side of an isolated obstacle increase in abundance, a phenomenon we call ‘geometry-enhanced genetic drift’, complementary to the founder effect associated with spatial bottlenecks. Bacterial range expansions around nutrient-poor barriers and stochastic simulations confirm this prediction. The effect of the obstacle on the genealogy of individuals at the front is characterized by simulations and rationalized using the constant speed model. Lastly, we consider the effect of two obstacles on front shape and genetic composition of the population illuminating the effects

Stepping over obstacles: anticipatory modifications in children with and without Down syndrome.

PubMed

Virji-Babul, Naznin; Brown, Michelle

2004-12-01

The purpose of this study was to explore the mechanism of anticipatory control of gait in relation to the perception of an obstacle. Typically developing (TD) children (4-7 years of age) and children with Down syndrome (5-6 years of age) walked and stepped over obstacles of two different heights-a "subtle" obstacle that was placed at a very low distance from the floor (1% of total body height) and an "obvious" obstacle that was placed at a much higher distance from the floor (15% of total body height). Spatial and temporal measures of the gait cycle were analyzed. TD children showed increased variability in pre-obstacle step lengths only in response to the higher obstacle. Children with DS showed a decrease in variability in response to the higher obstacle and marked qualitative changes in their gait cycle. Both groups of children were able to scale toe clearance with obstacle height. These results show that TD young children can make task-specific anticipatory adjustments by modulating step length and toe clearance. Children with DS show appropriate scaling of toe clearance and are beginning to show the emergence of anticipatory responses under specific environmental conditions.

A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots.

PubMed

Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il Dan

2016-03-01

This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%.

A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

PubMed Central

Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il “Dan”

2016-01-01

This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%. PMID:26938540

Clogging and jamming transitions in periodic obstacle arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Hong; Reichhardt, Charles; Olson Reichhardt, Cynthia Jane

2017-03-29

We numerically examine clogging transitions for bidisperse disks flowing through a two-dimensional periodic obstacle array. Here, we show that clogging is a probabilistic event that occurs through a transition from a homogeneous flowing state to a heterogeneous or phase-separated jammed state where the disks form dense connected clusters. The probability for clogging to occur during a fixed time increases with increasing particle packing and obstacle number. For driving at different angles with respect to the symmetry direction of the obstacle array, we show that certain directions have a higher clogging susceptibility. It is also possible to have a size-specific cloggingmore » transition in which one disk size becomes completely immobile while the other disk size continues to flow.« less

Obstacle detection and avoiding of quadcopter

NASA Astrophysics Data System (ADS)

Wang, Dizhong; Lin, Jiajian

2017-10-01

Recent years, the flight control technology over quadcopter has been boosted vigorously and acquired the comprehensive application in a variety of industries. However, it is prominent for there to be problems existed in the stable and secure flight with the development of its autonomous flight. Through comparing with the characteristics of ultrasonic ranging and laser Time-of-Flight(abbreviated to ToF) distance as well as vision measurement and its related sensors, the obstacle detection and identification sensors need to be installed in order to effectively enhance the safety flying for aircraft, which is essential for avoiding the dangers around the surroundings. That the major sensors applied to objects perception at present are distance measuring instruments which based on the principle and application of non-contact detection technology . Prior to acknowledging the general principles of flight and obstacle avoiding, the aerodynamics modeling of the quadcopter and its object detection means has been initially determined on this paper. Based on such premise, this article emphasized on describing and analyzing the research on obstacle avoiding technology and its application status, and making an expectation for the trend of its development after analyzing the primary existing problems concerning its accuracy object avoidance.

Strategies for Achieving the New SHAPE America Standards and Grade-Level Outcomes: Bringing Obstacle Course Training into Physical Education

ERIC Educational Resources Information Center

Kulik, Keri S.; Brewer, Hannah; Windish, Lance; Carlson, Hollie

2017-01-01

The new SHAPE America standards and grade level outcomes for high-school physical education focus exclusively on physical activities that are suitable for lifelong participation. Some of the fastest-growing physical activities for adults in the United States are non-traditional multi-sport events and obstacle course races. As "Healthy People…

The effects of multiple obstacles on the locomotor behavior and performance of a terrestrial lizard.

PubMed

Parker, Seth E; McBrayer, Lance D

2016-04-01

Negotiation of variable terrain is important for many small terrestrial vertebrates. Variation in the running surface resulting from obstacles (woody debris, vegetation, rocks) can alter escape paths and running performance. The ability to navigate obstacles likely influences survivorship through predator evasion success and other key ecological tasks (finding mates, acquiring food). Earlier work established that running posture and sprint performance are altered when organisms face an obstacle, and yet studies involving multiple obstacles are limited. Indeed, some habitats are cluttered with obstacles, whereas others are not. For many species, obstacle density may be important in predator escape and/or colonization potential by conspecifics. This study examines how multiple obstacles influence running behavior and locomotor posture in lizards. We predict that an increasing number of obstacles will increase the frequency of pausing and decrease sprint velocity. Furthermore, bipedal running over multiple obstacles is predicted to maintain greater mean sprint velocity compared with quadrupedal running, thereby revealing a potential advantage of bipedalism. Lizards were filmed running through a racetrack with zero, one or two obstacles. Bipedal running posture over one obstacle was significantly faster than quadrupedal posture. Bipedal running trials contained fewer total strides than quadrupedal ones. But on addition of a second obstacle, the number of bipedal strides decreased. Increasing obstacle number led to slower and more intermittent locomotion. Bipedalism provided clear advantages for one obstacle, but was not associated with further benefits for an additional obstacle. Hence, bipedalism helps mitigate obstacle negotiation, but not when numerous obstacles are encountered in succession. © 2016. Published by The Company of Biologists Ltd.

Stochastic performance modeling and evaluation of obstacle detectability with imaging range sensors

NASA Technical Reports Server (NTRS)

Matthies, Larry; Grandjean, Pierrick

1993-01-01

Statistical modeling and evaluation of the performance of obstacle detection systems for Unmanned Ground Vehicles (UGVs) is essential for the design, evaluation, and comparison of sensor systems. In this report, we address this issue for imaging range sensors by dividing the evaluation problem into two levels: quality of the range data itself and quality of the obstacle detection algorithms applied to the range data. We review existing models of the quality of range data from stereo vision and AM-CW LADAR, then use these to derive a new model for the quality of a simple obstacle detection algorithm. This model predicts the probability of detecting obstacles and the probability of false alarms, as a function of the size and distance of the obstacle, the resolution of the sensor, and the level of noise in the range data. We evaluate these models experimentally using range data from stereo image pairs of a gravel road with known obstacles at several distances. The results show that the approach is a promising tool for predicting and evaluating the performance of obstacle detection with imaging range sensors.

Obstacle evasion in free-space optical communications utilizing Airy beams.

PubMed

Zhu, Guoxuan; Wen, Yuanhui; Wu, Xiong; Chen, Yujie; Liu, Jie; Yu, Siyuan

2018-03-15

A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimizing their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.

Obstacle evasion in free-space optical communications utilizing Airy beams

NASA Astrophysics Data System (ADS)

Zhu, Guoxuan; Wen, Yuanhui; Wu, Xiong; Chen, Yujie; Liu, Jie; Yu, Siyuan

2018-03-01

A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimising their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.

Virtual reality as a tool for cross-cultural communication: an example from military team training

NASA Astrophysics Data System (ADS)

Downes-Martin, Stephen; Long, Mark; Alexander, Joanna R.

1992-06-01

A major problem with communication across cultures, whether professional or national, is that simple language translation if often insufficient to communicate the concepts. This is especially true when the communicators come from highly specialized fields of knowledge or from national cultures with long histories of divergence. This problem becomes critical when the goal of the communication is national negotiation dealing with such high risk items as arms negotiation or trade wars. Virtual Reality technology has considerable potential for facilitating communication across cultures, by immersing the communicators within multiple visual representations of the concepts, and providing control over those representations. Military distributed team training provides a model for virtual reality suitable for cross cultural communication such as negotiation. In both team training and negotiation, the participants must cooperate, agree on a set of goals, and achieve mastery over the concepts being negotiated. Team training technologies suitable for supporting cross cultural negotiation exist (branch wargaming, computer image generation and visualization, distributed simulation), and have developed along different lines than traditional virtual reality technology. Team training de-emphasizes the realism of physiological interfaces between the human and the virtual reality, and emphasizes the interaction of humans with each other and with intelligent simulated agents within the virtual reality. This approach to virtual reality is suggested as being more fruitful for future work.

The Evolution of Champion Cross-Country-Skier Training: From Lumberjacks to Professional Athletes.

PubMed

Sandbakk, Øyvind

2017-02-01

Competitive cross-country (XC) skiing has traditions extending back to the mid-19th century and was included as a men's event in the first Winter Games in 1924. Since then, tremendous improvements in equipment, track preparation, and knowledge about training have prompted greater increases in XC-skiing speeds than in any other Olympic sport. In response, this commentary focuses on how the training of successful XC skiers has evolved, with interviews and training data from surviving Norwegian world and Olympic XC champions as primary sources. Before 1970, most male champion XC skiers were lumberjacks who ran or skied long distances to and from felling areas while working long days in the woods. In addition, they trained as much as possible, with increased intensity during the autumn, while less work but more ski-specific training and competitions were done during the winter. Until the 1970s, few XC skiers were women, whom coaches believed tolerated less training than men did. Today's XC skiers are less physically active, but the influence of both science and the systematic approaches of former athletes and coaches have gradually taught XC skiers to adopt smarter, more goal-oriented training practices. Although the very high VO 2 max of world-class XC skiers has remained the same since the 1960s, new events in modern XC skiing have additionally required superior upper-body power, high-speed techniques, and tactical flexibility. These elements also emerge in the training of today's best skiers; women's physiological capacities and training routines especially seem to have improved dramatically.

Propagation of spiral waves pinned to circular and rectangular obstacles.

PubMed

Sutthiopad, Malee; Luengviriya, Jiraporn; Porjai, Porramain; Phantu, Metinee; Kanchanawarin, Jarin; Müller, Stefan C; Luengviriya, Chaiya

2015-05-01

We present an investigation of spiral waves pinned to circular and rectangular obstacles with different circumferences in both thin layers of the Belousov-Zhabotinsky reaction and numerical simulations with the Oregonator model. For circular objects, the area always increases with the circumference. In contrast, we varied the circumference of rectangles with equal areas by adjusting their width w and height h. For both obstacle forms, the propagating parameters (i.e., wavelength, wave period, and velocity of pinned spiral waves) increase with the circumference, regardless of the obstacle area. Despite these common features of the parameters, the forms of pinned spiral waves depend on the obstacle shapes. The structures of spiral waves pinned to circles as well as rectangles with the ratio w/h∼1 are similar to Archimedean spirals. When w/h increases, deformations of the spiral shapes are observed. For extremely thin rectangles with w/h≫1, these shapes can be constructed by employing semicircles with different radii which relate to the obstacle width and the core diameter of free spirals.

Virtual reality-based navigation task to reveal obstacle avoidance performance in individuals with visuospatial neglect.

PubMed

Aravind, Gayatri; Darekar, Anuja; Fung, Joyce; Lamontagne, Anouk

2015-03-01

Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30 (°) contralesionally/ipsilesionally. Our results indicate that in the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. We conclusion the observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alter obstacle avoidance abilities.

Assessment of a simple obstacle detection device for the visually impaired.

PubMed

Lee, Cheng-Lung; Chen, Chih-Yung; Sung, Peng-Cheng; Lu, Shih-Yi

2014-07-01

A simple obstacle detection device, based upon an automobile parking sensor, was assessed as a mobility aid for the visually impaired. A questionnaire survey for mobility needs was performed at the start of this study. After the detector was developed, five blindfolded sighted and 15 visually impaired participants were invited to conduct travel experiments under three test conditions: (1) using a white cane only, (2) using the obstacle detector only and (3) using both devices. A post-experiment interview regarding the usefulness of the obstacle detector for the visually impaired participants was performed. The results showed that the obstacle detector could augment mobility performance with the white cane. The obstacle detection device should be used in conjunction with the white cane to achieve the best mobility speed and body protection. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Training a Network of Electronic Neurons for Control of a Mobile Robot

NASA Astrophysics Data System (ADS)

Vromen, T. G. M.; Steur, E.; Nijmeijer, H.

An adaptive training procedure is developed for a network of electronic neurons, which controls a mobile robot driving around in an unknown environment while avoiding obstacles. The neuronal network controls the angular velocity of the wheels of the robot based on the sensor readings. The nodes in the neuronal network controller are clusters of neurons rather than single neurons. The adaptive training procedure ensures that the input-output behavior of the clusters is identical, even though the constituting neurons are nonidentical and have, in isolation, nonidentical responses to the same input. In particular, we let the neurons interact via a diffusive coupling, and the proposed training procedure modifies the diffusion interaction weights such that the neurons behave synchronously with a predefined response. The working principle of the training procedure is experimentally validated and results of an experiment with a mobile robot that is completely autonomously driving in an unknown environment with obstacles are presented.

Through the eyes of a bird: modelling visually guided obstacle flight

PubMed Central

Lin, Huai-Ti; Ros, Ivo G.; Biewener, Andrew A.

2014-01-01

Various flight navigation strategies for birds have been identified at the large spatial scales of migratory and homing behaviours. However, relatively little is known about close-range obstacle negotiation through cluttered environments. To examine obstacle flight guidance, we tracked pigeons (Columba livia) flying through an artificial forest of vertical poles. Interestingly, pigeons adjusted their flight path only approximately 1.5 m from the forest entry, suggesting a reactive mode of path planning. Combining flight trajectories with obstacle pole positions, we reconstructed the visual experience of the pigeons throughout obstacle flights. Assuming proportional–derivative control with a constant delay, we searched the relevant parameter space of steering gains and visuomotor delays that best explained the observed steering. We found that a pigeon's steering resembles proportional control driven by the error angle between the flight direction and the desired opening, or gap, between obstacles. Using this pigeon steering controller, we simulated obstacle flights and showed that pigeons do not simply steer to the nearest opening in the direction of flight or destination. Pigeons bias their flight direction towards larger visual gaps when making fast steering decisions. The proposed behavioural modelling method converts the obstacle avoidance behaviour into a (piecewise) target-aiming behaviour, which is better defined and understood. This study demonstrates how such an approach decomposes open-loop free-flight behaviours into components that can be independently evaluated. PMID:24812052

Through the eyes of a bird: modelling visually guided obstacle flight.

PubMed

Lin, Huai-Ti; Ros, Ivo G; Biewener, Andrew A

2014-07-06

Various flight navigation strategies for birds have been identified at the large spatial scales of migratory and homing behaviours. However, relatively little is known about close-range obstacle negotiation through cluttered environments. To examine obstacle flight guidance, we tracked pigeons (Columba livia) flying through an artificial forest of vertical poles. Interestingly, pigeons adjusted their flight path only approximately 1.5 m from the forest entry, suggesting a reactive mode of path planning. Combining flight trajectories with obstacle pole positions, we reconstructed the visual experience of the pigeons throughout obstacle flights. Assuming proportional-derivative control with a constant delay, we searched the relevant parameter space of steering gains and visuomotor delays that best explained the observed steering. We found that a pigeon's steering resembles proportional control driven by the error angle between the flight direction and the desired opening, or gap, between obstacles. Using this pigeon steering controller, we simulated obstacle flights and showed that pigeons do not simply steer to the nearest opening in the direction of flight or destination. Pigeons bias their flight direction towards larger visual gaps when making fast steering decisions. The proposed behavioural modelling method converts the obstacle avoidance behaviour into a (piecewise) target-aiming behaviour, which is better defined and understood. This study demonstrates how such an approach decomposes open-loop free-flight behaviours into components that can be independently evaluated.

An assessment of auditory-guided locomotion in an obstacle circumvention task.

PubMed

Kolarik, Andrew J; Scarfe, Amy C; Moore, Brian C J; Pardhan, Shahina

2016-06-01

This study investigated how effectively audition can be used to guide navigation around an obstacle. Ten blindfolded normally sighted participants navigated around a 0.6 × 2 m obstacle while producing self-generated mouth click sounds. Objective movement performance was measured using a Vicon motion capture system. Performance with full vision without generating sound was used as a baseline for comparison. The obstacle's location was varied randomly from trial to trial: it was either straight ahead or 25 cm to the left or right relative to the participant. Although audition provided sufficient information to detect the obstacle and guide participants around it without collision in the majority of trials, buffer space (clearance between the shoulder and obstacle), overall movement times, and number of velocity corrections were significantly (p < 0.05) greater with auditory guidance than visual guidance. Collisions sometime occurred under auditory guidance, suggesting that audition did not always provide an accurate estimate of the space between the participant and obstacle. Unlike visual guidance, participants did not always walk around the side that afforded the most space during auditory guidance. Mean buffer space was 1.8 times higher under auditory than under visual guidance. Results suggest that sound can be used to generate buffer space when vision is unavailable, allowing navigation around an obstacle without collision in the majority of trials.

Effects of a virtual reality and treadmill training on gait of subjects with multiple sclerosis: a pilot study.

PubMed

Peruzzi, Agnese; Cereatti, Andrea; Della Croce, Ugo; Mirelman, Anat

2016-01-01

Gait and cognitive deficits are common in multiple sclerosis (MS) and are negatively affected during dual-task walking. Treadmill (TM) training has been previously used to preserve locomotor activity in MS. Virtual reality (VR) engages the user in cognitive and motor activities simultaneously. A training combining TM and VR has been successfully adopted in several neurological diseases, but not in MS. This study aims at investigating the feasibility of a VR-based TM training program on gait of subjects with MS. Eight persons with relapsing-remitting MS were recruited to participate in a six-week VR-based TM training program. Gait analysis was performed both in single and dual task conditions. Clinical tests were used to assess walking endurance and obstacle negotiation. All the evaluations were performed before, immediately and one month after the training. Gait speed and stride length improved in dual task post-intervention and were retained at follow-up. An improved ability in negotiating obstacles was found across the evaluations. VR-based TM training program is feasible and safe for MS subjects with moderate disabilities and may positively affect gait under complex conditions, such as dual tasking and obstacle negotiation. Copyright © 2015. Published by Elsevier B.V.

Real-time obstacle avoidance using harmonic potential functions

NASA Technical Reports Server (NTRS)

Kim, Jin-Oh; Khosla, Pradeep K.

1992-01-01

This paper presents a new formulation of the artificial potential approach to the obstacle avoidance problem for a mobile robot or a manipulator in a known environment. Previous formulations of artificial potentials for obstacle avoidance have exhibited local minima in a cluttered environment. To build an artificial potential field, harmonic functions that completely eliminate local minima even for a cluttered environment are used. The panel method is employed to represent arbitrarily shaped obstacles and to derive the potential over the whole space. Based on this potential function, an elegant control strategy is proposed for the real-time control of a robot. The harmonic potential, the panel method, and the control strategy are tested with a bar-shaped mobile robot and a three-degree-of-freedom planar redundant manipulator.

A Real-Time Reaction Obstacle Avoidance Algorithm for Autonomous Underwater Vehicles in Unknown Environments.

PubMed

Yan, Zheping; Li, Jiyun; Zhang, Gengshi; Wu, Yi

2018-02-02

A novel real-time reaction obstacle avoidance algorithm (RRA) is proposed for autonomous underwater vehicles (AUVs) that must adapt to unknown complex terrains, based on forward looking sonar (FLS). To accomplish this algorithm, obstacle avoidance rules are planned, and the RRA processes are split into five steps Introduction only lists 4 so AUVs can rapidly respond to various environment obstacles. The largest polar angle algorithm (LPAA) is designed to change detected obstacle's irregular outline into a convex polygon, which simplifies the obstacle avoidance process. A solution is designed to solve the trapping problem existing in U-shape obstacle avoidance by an outline memory algorithm. Finally, simulations in three unknown obstacle scenes are carried out to demonstrate the performance of this algorithm, where the obtained obstacle avoidance trajectories are safety, smooth and near-optimal.

Numerical investigation on layout optimization of obstacles in a three-dimensional passive micromixer.

PubMed

Chen, Xueye; Zhao, Zhongyi

2017-04-29

This paper aims at layout optimization design of obstacles in a three-dimensional T-type micromixer. Numerical analysis shows that the direction of flow velocity change constantly due to the obstacles blocking, which produces the chaotic convection and increases species mixing effectively. The orthogonal experiment method was applied for determining the effects of some key parameters on mixing efficiency. The weights in the order are: height of obstacles > geometric shape > symmetry = number of obstacles. Based on the optimized results, a multi-units obstacle micromixer was designed. Compared with T-type micromixer, the multi-units obstacle micromixer is more efficient, and more than 90% mixing efficiency were obtained for a wide range of peclet numbers. It can be demonstrated that the presented optimal design method of obstacles layout in three-dimensional microchannels is a simple and effective technology to improve species mixing in microfluidic devices. The obstacles layout methodology has the potential for applications in chemical engineering and bioengineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Participative Evaluation and the Quality of Community Empowerment Training of "Program Keluarga Harapan" (PKH) Companions

ERIC Educational Resources Information Center

Rasyad, Ach.

2016-01-01

This research is aiming at describing: (1) the implementation of community empowerment training of PKH companions, (2) types of participative evaluation used in the PKH companion training, and (3) obstacles and supporting factors in PKH companion training using the participative evaluation. The study employed qualitative approach with case study…

What shape do UK trainees want their training to be? Results of a cross-sectional study.

PubMed

Harries, Rhiannon L; Rashid, Mustafa; Smitham, Peter; Vesey, Alex; McGregor, Richard; Scheeres, Karl; Bailey, Jon; Sohaib, Syed Mohammed Afzal; Prior, Matthew; Frost, Jonathan; Al-Deeb, Walid; Kugathasan, Gana; Gokani, Vimal J

2016-10-07

The British Government is acting on recommendations to overhaul postgraduate training to meet the needs of the changing population, to produce generalist doctors undergoing shorter broad-based training (Greenaway Review). Only 45 doctors in training were involved in the consultation process. This study aims to obtain a focused perspective on the proposed reforms by doctors in training from across specialities. Prospective, questionnaire-based cross-sectional study. Following validation, a 31-item electronic questionnaire was distributed via trainee organisations and Postgraduate Local Education and Training Board (LETB) mailing lists. Throughout the 10-week study period, the survey was publicised on several social media platforms. Of the 3603 demographically representative respondents, 69% knew about proposed changes. Of the respondents, 73% expressed a desire to specialise, with 54% keen to provide general emergency cover. A small proportion (12%) stated that current training pathway length is too long, although 86% felt that it is impossible to achieve independent practitioner-level proficiency in a shorter period of time than is currently required. Opinions regarding credentialing were mixed, but tended towards disagreement. The vast majority (97%) felt credentialing should not be funded by doctors in training. Respondents preferred longer placement lengths with increasing career progression. Doctors in training value early generalised training (65%), with suggestions for further improvement. This is the first large-scale cross-specialty study regarding the Shape of Training Review. Although there are recommendations which trainees support, it is clear that one size does not fit all. Most trainees are keen to provide a specialist service on an emergency generalist background. Credentialing is a contentious issue; however, we believe removing aspects from curricula into post-Certificate of Completion of Training (CCT) credentialing programmes with shortened

Integrated surgical academic training in the UK: a cross-sectional survey

PubMed Central

Blencowe, Natalie S; McElnay, Philip J; Bhangu, Aneel; Gokani, Vimal J; Harries, Rhiannon L

2017-01-01

Objectives This study aimed to explore variations in the provision of integrated academic surgical training across the UK. Design This is an online cross-sectional survey (consisting of 44 items with a range of free-text, binomial and 5-point Likert scale responses) developed by the Association of Surgeons in Training. Setting A self-reported survey instrument was distributed to academic surgical trainees across the UK (n=276). Participants 143 (51.9%) responses were received (81% male, median age: 34 years), spanning all UK regions and surgical specialties. Of the 143 trainees, 29 were core trainees (20.3%), 99 were specialty trainees (69.2%) and 15 (10.5%) described themselves as research fellows. Results The structure of academic training varied considerably, with under a third of trainees receiving guaranteed protected time for research. Despite this, however, 53.1% of the respondents reported to be satisfied with how their academic training was organised. Covering clinical duties during academic time occurred commonly (72.7%). Although most trainees (n=88, 61.5%) met with their academic supervisor at least once a month, six (4.2%) never had an academic supervisory meeting. Most trainees (n=90, 62.9%) occupied a full-time rota slot and only 9.1% (n=13) described their role as ‘supernumerary’. Although 58.7% (n=84) of the trainees were satisfied with their clinical competence, 37.8% (n=54) felt that clinical time focused more on service provision than the acquisition of technical skills. 58 (40.6%) had experienced some form of negative sentiment relating to their status as an academic trainee. Conclusions Integrated academic training presents unique challenges and opportunities within surgery. This survey has identified variation in the quality of current programmes, meaning that the future provision of integrated surgical academic training should be carefully considered. PMID:28408726

Radar detection with the Neyman-Pearson criterion using supervised-learning-machines trained with the cross-entropy error

NASA Astrophysics Data System (ADS)

Jarabo-Amores, María-Pilar; la Mata-Moya, David de; Gil-Pita, Roberto; Rosa-Zurera, Manuel

2013-12-01

The application of supervised learning machines trained to minimize the Cross-Entropy error to radar detection is explored in this article. The detector is implemented with a learning machine that implements a discriminant function, which output is compared to a threshold selected to fix a desired probability of false alarm. The study is based on the calculation of the function the learning machine approximates to during training, and the application of a sufficient condition for a discriminant function to be used to approximate the optimum Neyman-Pearson (NP) detector. In this article, the function a supervised learning machine approximates to after being trained to minimize the Cross-Entropy error is obtained. This discriminant function can be used to implement the NP detector, which maximizes the probability of detection, maintaining the probability of false alarm below or equal to a predefined value. Some experiments about signal detection using neural networks are also presented to test the validity of the study.

A game theory-based obstacle avoidance routing protocol for wireless sensor networks.

PubMed

Guan, Xin; Wu, Huayang; Bi, Shujun

2011-01-01

The obstacle avoidance problem in geographic forwarding is an important issue for location-based routing in wireless sensor networks. The presence of an obstacle leads to several geographic routing problems such as excessive energy consumption and data congestion. Obstacles are hard to avoid in realistic environments. To bypass obstacles, most routing protocols tend to forward packets along the obstacle boundaries. This leads to a situation where the nodes at the boundaries exhaust their energy rapidly and the obstacle area is diffused. In this paper, we introduce a novel routing algorithm to solve the obstacle problem in wireless sensor networks based on a game-theory model. Our algorithm forms a concave region that cannot forward packets to achieve the aim of improving the transmission success rate and decreasing packet transmission delays. We consider the residual energy, out-degree and forwarding angle to determine the forwarding probability and payoff function of forwarding candidates. This achieves the aim of load balance and reduces network energy consumption. Simulation results show that based on the average delivery delay, energy consumption and packet delivery ratio performances our protocol is superior to other traditional schemes.

Obstacle detectors for automated transit vehicles: A technoeconomic and market analysis

NASA Technical Reports Server (NTRS)

Lockerby, C. E.

1979-01-01

A search was conducted to identify the technical and economic characteristics of both NASA and nonNASA obstacle detectors. The findings, along with market information were compiled and analyzed for consideration by DOT and NASA in decisions about any future automated transit vehicle obstacle detector research, development, or applications project. Currently available obstacle detectors and systems under development are identified by type (sonic, capacitance, infrared/optical, guided radar, and probe contact) and compared with the three NASA devices selected as possible improvements or solutions to the problems in existing obstacle detection systems. Cost analyses and market forecasts individually for the AGT and AMTV markets are included.

Research on robot mobile obstacle avoidance control based on visual information

NASA Astrophysics Data System (ADS)

Jin, Jiang

2018-03-01

Robots to detect obstacles and control robots to avoid obstacles has been a key research topic of robot control. In this paper, a scheme of visual information acquisition is proposed. By judging visual information, the visual information is transformed into the information source of path processing. In accordance with the established route, in the process of encountering obstacles, the algorithm real-time adjustment trajectory to meet the purpose of intelligent control of mobile robots. Simulation results show that, through the integration of visual sensing information, the obstacle information is fully obtained, while the real-time and accuracy of the robot movement control is guaranteed.

A comprehensive assessment of the cross-training effect in ankle dorsiflexors of healthy subjects: A randomized controlled study.

PubMed

Manca, Andrea; Pisanu, Francesco; Ortu, Enzo; De Natale, Edoardo Rosario; Ginatempo, Francesca; Dragone, Daniele; Tolu, Eusebio; Deriu, Franca

2015-06-01

To investigate the cross-training effect, induced on ankle dorsiflexors (AD) by unilateral strength-training of the contralateral muscles, as transfer of peak torque (PT) and muscle work (MW) and their relative contributions to muscle performance. Thirty healthy volunteers were randomly assigned to a training or control group. The trained group sustained a 4-week maximal isokinetic training of the stronger AD at 90 and 45°/s. At both angular velocities, PT, MW and MW/PT ratio were measured from both legs at baseline and after intervention (trained group) or no-intervention (controls). The familiarization/learning-effect was calculated and subtracted by PT and MW measures to obtain their net changes. Net PT increased in both legs (untrained: +27.5% at 90°/s and +17.9% at 45°/s; trained: +15% at 90°/s and +16.3% at 45°/s). Similarly, net MW increased in both the untrained (90°/s: +29.6%; 45°/s: +37%) and trained (90°/s: +23.4%; 45°/s: +18.3%) legs. PT and MW gains were larger in the untrained than trained AD (p<0.0005), with MW improving more than PT at 45°/s (p=0.04). The MW/PT ratio increased bilaterally only in the trained group (p<0.05), depending on the angular velocity. The cross-training effect occurred in AD muscles in terms of both PT and MW, with MW adding valuable information to PT-analysis in describing muscle performance. Moreover, the MW/PT ratio allowed estimating the contributions of these parameters to muscle capability and may represent a novel index in isokinetic testing. The greater improvements in the untrained than trained limb raises interesting clinical implications in asymmetric conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

TRAINING OLDER WORKERS FOR TECHNOLOGY-BASED EMPLOYMENT.

PubMed

Lee, Chin Chin; Czaja, Sara J; Sharit, Joseph

2009-01-01

An increasingly aging workforce and advances in technology are changing work environments and structures. The continued employability of older adults, particularly those of lower socioeconomic status (SES), requires them to participate in training programs to ensure their competence in today's workplace. Focus groups with 37 unemployed adults (51-76 years old) were conducted to gather information about barriers and obstacles for returning to work, training needs and formats, work experiences, and perceptions of the characteristics of an ideal job. Overall, results indicated that participants experienced age discrimination and lack of technology skills. They also expressed a desire to receive additional training on technology and a preference for classroom training.

Optimal layout design of obstacles for panic evacuation using differential evolution

NASA Astrophysics Data System (ADS)

Zhao, Yongxiang; Li, Meifang; Lu, Xin; Tian, Lijun; Yu, Zhiyong; Huang, Kai; Wang, Yana; Li, Ting

2017-01-01

To improve the pedestrian outflow in panic situations by suitably placing an obstacle in front of the exit, it is vital to understand the physical mechanism behind the evacuation efficiency enhancement. In this paper, a robust differential evolution is firstly employed to optimize the geometrical parameters of different shaped obstacles in order to achieve an optimal evacuation efficiency. Moreover, it is found that all the geometrical parameters of obstacles could markedly influence the evacuation efficiency of pedestrians, and the best way for achieving an optimal pedestrian outflow is to slightly shift the obstacle from the center of the exit which is consistent with findings of extant literature. Most importantly, by analyzing the profiles of density, velocity and specific flow, as well as the spatial distribution of crowd pressure, we have proven that placing an obstacle in panic situations does not reduce or absorb the pressure in the region of exit, on the contrary, promotes the pressure to a much higher level, hence the physical mechanism behind the evacuation efficiency enhancement is not a pressure decrease in the region of exit, but a significant reduction of high density region by effective separation in space which finally causes the increasing of escape speed and evacuation outflow. Finally, it is clearly demonstrated that the panel-like obstacle is considerably more robust and stable than the pillar-like obstacle to guarantee the enhancement of evacuation efficiency under different initial pedestrian distributions, different initial crowd densities as well as different desired velocities.

Laterality and performance of agility-trained dogs.

PubMed

Siniscalchi, Marcello; Bertino, Daniele; Quaranta, Angelo

2014-01-01

Correlations between lateralised behaviour and performance were investigated in 19 agility-trained dogs (Canis familiaris) by scoring paw preference to hold a food object and relating it to performance during typical agility obstacles (jump/A-frame and weave poles). In addition, because recent behavioural studies reported that visual stimuli of emotional valence presented to one visual hemifield at a time affect visually guided motor responses in dogs, the possibility that the position of the owner respectively in the left and in the right canine visual hemifield might be associated with quality of performance during agility was considered. Dogs' temperament was also measured by an owner-rated questionnaire. The most relevant finding was that agility-trained dogs displayed longer latencies to complete the obstacles with the owner located in their left visual hemifield compared to the right. Interestingly, the results showed that this phenomenon was significantly linked to both dogs' trainability and the strength of paw preference.

Gendered Obstacles Faced by Historical Women in Physics and Astronomy

NASA Astrophysics Data System (ADS)

Jones, Kristen M.

2007-12-01

A gender gap still exists in modern science; this is especially evident in the fields of physics and astronomy. The cause of such a gap is the center of debate. Is this discrepancy the result of inherent ability or socialization? Most studies have focused on modern issues and how women are socialized today. The role of historical gender perspectives and social opinions in creating the field of modern science and any discrepancies within it has not yet been explored in depth. This project investigates the obstacles faced by historical women in physics and astronomy that stem from the officialized gender biases that accompanied the establishment of modern science. Such obstacles are both formal and informal. Four women were chosen to span the three hundred year period between the standardization of the field and the modern day: Laura Bassi, Mary Somerville, Lise Meitner, and Jocelyn Bell Burnell. The investigation reveals that formal obstacles significantly decreased over the time period, while informal obstacles eroded more gradually. Obstacles also reflected historical events such as the World Wars and the Enlightenment. Trends in obstacles faced by four prominent women physicists indicate that education, finances, support networks, and social opinion played a large role in determining success in the field. The applicability to modern day physics issues and the gender gap is discussed. Many thanks to the Pathways Scholars Program and the Ronald E. McNair Post-Baccalaureate Achievement Program for funding for this project.

Comparisons of Perceived Training Doses in Champion Collegiate-Level Male and Female Cross-country Runners and Coaches over the Course of a Competitive Season.

PubMed

Barnes, Kyle R

2017-10-17

Session rating of perceived exertion (sRPE) is a practical tool for coaches to assess internal training load of their athletes. In a sport like cross-country running, that is individual in nature, but has a team training and competition component, information about the association between external and internal load is lacking. Furthermore, there is a need for studies that examine perception of training doses across multiple training cycles including the competitive season as well as between male and female athletes. Session RPE, duration, and training load (TL RPE  = sRPE × duration) of 25 highly trained male and female cross-country runners and their coaches were recorded for every training session (110 days) throughout a collegiate cross-country season. Intensity (sRPE), duration, and TL RPE were compared between coaches and runners by gender separately. Training sessions were also analyzed by those intended by the coaches to be easy, moderate, and hard as well as by training period. Data from 3024 training sessions were collected, 62% of which were considered "easy," 18% "moderate," and 20% "hard." Men and women rated coach-intended easy sessions significantly harder during each month of the season (effect size (ES) > 2.9, p < 0.0001). Men rated moderate intensity sessions significantly higher than coaches (ES ≥ 1.0, p ≤ 0.002), whereas females rated hard intensity sessions significantly lower than coaches (ES > 0.5, p < 0.008). There was no difference between males and coach's hard sessions (ES < 0.07, p > 0.05) or females and coach's moderate sessions (ES < 0.18, p > 0.05). Training intensity and TL RPE tended to increase throughout the season (p > 0.05), with a significant increase in moderate and hard intensity sessions in the last training period (p < 0.001). The results indicate the male and female cross-country runners tend to regress to moderate intensity training throughout the cross-country season

Bim-Based Indoor Path Planning Considering Obstacles

NASA Astrophysics Data System (ADS)

Xu, M.; Wei, S.; Zlatanova, S.; Zhang, R.

2017-09-01

At present, 87 % of people's activities are in indoor environment; indoor navigation has become a research issue. As the building structures for people's daily life are more and more complex, many obstacles influence humans' moving. Therefore it is essential to provide an accurate and efficient indoor path planning. Nowadays there are many challenges and problems in indoor navigation. Most existing path planning approaches are based on 2D plans, pay more attention to the geometric configuration of indoor space, often ignore rich semantic information of building components, and mostly consider simple indoor layout without taking into account the furniture. Addressing the above shortcomings, this paper uses BIM (IFC) as the input data and concentrates on indoor navigation considering obstacles in the multi-floor buildings. After geometric and semantic information are extracted, 2D and 3D space subdivision methods are adopted to build the indoor navigation network and to realize a path planning that avoids obstacles. The 3D space subdivision is based on triangular prism. The two approaches are verified by the experiments.

Obstacle avoidance system with sonar sensing and fuzzy logic

NASA Astrophysics Data System (ADS)

Chiang, Wen-chuan; Kelkar, Nikhal; Hall, Ernest L.

1997-09-01

Automated guided vehicles (AGVs) have many potential applications in manufacturing, medicine, space and defense. The purpose of this paper is to describe exploratory research on the design of an obstacle avoidance system using sonar sensors for a modular autonomous mobile robot controller. The advantages of a modular system are related to portability and the fact that any vehicle can become autonomous with minimal modifications. A mobile robot test-bed has been constructed using a golf cart base. The obstacle avoidance system is based on a micro-controller interfaced with multiple ultrasonic transducers. This micro-controller independently handles all timing and distance calculations and sends a distance measurement back to the computer via the serial line. This design yields a portable independent system. Testing of these systems has been done in the lab as well as on an outside test track with positive results that show that at five mph the vehicle can follow a line and at the same time avoid obstacles. This design, in its modularity, creates a portable autonomous obstacle avoidance controller applicable for any mobile vehicle with only minor adaptations.

Automatic Quadcopter Control Avoiding Obstacle Using Camera with Integrated Ultrasonic Sensor

NASA Astrophysics Data System (ADS)

Anis, Hanafi; Haris Indra Fadhillah, Ahmad; Darma, Surya; Soekirno, Santoso

2018-04-01

Automatic navigation on the drone is being developed these days, a wide variety of types of drones and its automatic functions. Drones used in this study was an aircraft with four propellers or quadcopter. In this experiment, image processing used to recognize the position of an object and ultrasonic sensor used to detect obstacle distance. The method used to trace an obsctacle in image processing was the Lucas-Kanade-Tomasi Tracker, which had been widely used due to its high accuracy. Ultrasonic sensor used to complement the image processing success rate to be fully detected object. The obstacle avoidance system was to observe at the program decisions from some obstacle conditions read by the camera and ultrasonic sensors. Visual feedback control based PID controllers are used as a control of drones movement. The conclusion of the obstacle avoidance system was to observe at the program decisions from some obstacle conditions read by the camera and ultrasonic sensors.

Apparatus for obstacle traversion

DOEpatents

Borenstein, Johann

2004-08-10

An apparatus for traversing obstacles having an elongated, round, flexible body that includes a plurality of drive track assemblies. The plurality of drive track assemblies cooperate to provide forward propulsion wherever a propulsion member is in contact with any feature of the environment, regardless of how many or which ones of the plurality of drive track assemblies make contact with such environmental feature.

Web-based training and interrater reliability testing for scoring the Hamilton Depression Rating Scale.

PubMed

Rosen, Jules; Mulsant, Benoit H; Marino, Patricia; Groening, Christopher; Young, Robert C; Fox, Debra

2008-10-30

Despite the importance of establishing shared scoring conventions and assessing interrater reliability in clinical trials in psychiatry, these elements are often overlooked. Obstacles to rater training and reliability testing include logistic difficulties in providing live training sessions, or mailing videotapes of patients to multiple sites and collecting the data for analysis. To address some of these obstacles, a web-based interactive video system was developed. It uses actors of diverse ages, gender and race to train raters how to score the Hamilton Depression Rating Scale and to assess interrater reliability. This system was tested with a group of experienced and novice raters within a single site. It was subsequently used to train raters of a federally funded multi-center clinical trial on scoring conventions and to test their interrater reliability. The advantages and limitations of using interactive video technology to improve the quality of clinical trials are discussed.

Training practitioners in preparing systematic reviews: a cross-sectional survey of participants in the Australasian Cochrane Centre training program

PubMed Central

Piehl, Janet H; Green, Sally; Silagy, Chris

2002-01-01

Background Although systematic reviews of health care interventions are an invaluable tool for health care providers and researchers, many potential authors never publish reviews. This study attempts to determine why some people with interest in performing systematic reviews do not subsequently publish a review; and what steps could possibly increase review completion. Methods Cross-sectional survey by email and facsimile of the 179 participants in Australasian Cochrane Centre training events between 1998 and 2000. Results Ninety-two participants responded to the survey (51 percent). Response rate of deliverable surveys was 82 percent (92/112). The remainder of the participants had invalid or no contact information on file. More than 75 percent of respondents felt that the current workshops met their needs for training. The most critical barriers to completion of a Cochrane review were: lack of time (80 percent), lack of financial support (36 percent), methodological problems (23 percent) and problems with group dynamics (10 percent). Conclusions Strategies to protect reviewer time and increase the efficiency of the review process may increase the numbers of trained reviewers completing a systematic review. PMID:12057022

Training practitioners in preparing systematic reviews: a cross-sectional survey of participants in the Australasian Cochrane Centre training program.

PubMed

Piehl, Janet H; Green, Sally; Silagy, Chris

2002-06-02

Although systematic reviews of health care interventions are an invaluable tool for health care providers and researchers, many potential authors never publish reviews. This study attempts to determine why some people with interest in performing systematic reviews do not subsequently publish a review; and what steps could possibly increase review completion. Cross-sectional survey by email and facsimile of the 179 participants in Australasian Cochrane Centre training events between 1998 and 2000. Ninety-two participants responded to the survey (51 percent). Response rate of deliverable surveys was 82 percent (92/112). The remainder of the participants had invalid or no contact information on file. More than 75 percent of respondents felt that the current workshops met their needs for training. The most critical barriers to completion of a Cochrane review were: lack of time (80 percent), lack of financial support (36 percent), methodological problems (23 percent) and problems with group dynamics (10 percent). Strategies to protect reviewer time and increase the efficiency of the review process may increase the numbers of trained reviewers completing a systematic review.

Obstacle negotiation control for a mobile robot suspended on overhead ground wires by optoelectronic sensors

NASA Astrophysics Data System (ADS)

Zheng, Li; Yi, Ruan

2009-11-01

Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

Generation of spiral waves pinned to obstacles in a simulated excitable system

NASA Astrophysics Data System (ADS)

Phantu, Metinee; Kumchaiseemak, Nakorn; Porjai, Porramain; Sutthiopad, Malee; Müller, Stefan C.; Luengviriya, Chaiya; Luengviriya, Jiraporn

2017-09-01

Pinning phenomena emerge in many dynamical systems. They are found to stabilize extreme conditions such as superconductivity and super fluidity. The dynamics of pinned spiral waves, whose tips trace the boundary of obstacles, also play an important role in the human health. In heart, such pinned waves cause longer tachycardia. In this article, we present two methods for generating pinned spiral waves in a simulated excitable system. In method A, an obstacle is set in the system prior to an ignition of a spiral wave. This method may be suitable only for the case of large obstacles since it often fails when used for small obstacles. In method B, a spiral wave is generated before an obstacle is placed at the spiral tip. With this method, a pinned spiral wave is always obtained, regardless the obstacle size. We demonstrate that after a transient interval the dynamics of the pinned spiral waves generated by the methods A and B are identical. The initiation of pinned spiral waves in both two- and three-dimensional systems is illustrated.

Short-Term Unilateral Resistance Training Results in Cross Education of Strength Without Changes in Muscle Size, Activation, or Endocrine Response.

PubMed

Beyer, Kyle S; Fukuda, David H; Boone, Carleigh H; Wells, Adam J; Townsend, Jeremy R; Jajtner, Adam R; Gonzalez, Adam M; Fragala, Maren S; Hoffman, Jay R; Stout, Jeffrey R

2016-05-01

Short-term unilateral resistance training results in cross education of strength without changes in muscle size, activation, or endocrine response. J Strength Cond Res 30(5): 1213-1223, 2016-The purpose of this study was to assess the cross education of strength and changes in the underlying mechanisms (muscle size, activation, and hormonal response) after a 4-week unilateral resistance training (URT) program. A group of 9 untrained men completed a 4-week URT program on the dominant leg (DOM), whereas cross education was measured in the nondominant leg (NON); and were compared with a control group (n = 8, CON). Unilateral isometric force (PKF), leg press (LP) and leg extension (LE) strength, muscle size (by ultrasonography) and activation (by electromyography) of the rectus femoris and vastus lateralis, and the hormonal response (testosterone, growth hormone, insulin, and insulin-like growth factor-1) were tested pretraining and posttraining. Group × time interactions were present for PKF, LP, LE, and muscle size in DOM and for LP in NON. In all interactions, the URT group improved significantly better than CON. There was a significant acute hormonal response to URT, but no chronic adaptation after the 4-week training program. Four weeks of URT resulted in an increase in strength and size of the trained musculature, and cross education of strength in the untrained musculature, which may occur without detectable changes in muscle size, activation, or the acute hormonal response.

TOOLS FOR OVERCOMING OBSTACLES TO REVITALIZATION: SMARTE AND START-UP

EPA Science Inventory

In 2001, the US-German Bilateral Working Group (BWG) identified more than 40 obstacles to site revitalization which occurred in both countries. From 2001-2005, the BWG developed tools and techniques for overcoming these obstacles. Five joint workshops were held on the following r...

A Real-Time Reaction Obstacle Avoidance Algorithm for Autonomous Underwater Vehicles in Unknown Environments

PubMed Central

Yan, Zheping; Li, Jiyun; Zhang, Gengshi; Wu, Yi

2018-01-01

A novel real-time reaction obstacle avoidance algorithm (RRA) is proposed for autonomous underwater vehicles (AUVs) that must adapt to unknown complex terrains, based on forward looking sonar (FLS). To accomplish this algorithm, obstacle avoidance rules are planned, and the RRA processes are split into five steps Introduction only lists 4 so AUVs can rapidly respond to various environment obstacles. The largest polar angle algorithm (LPAA) is designed to change detected obstacle’s irregular outline into a convex polygon, which simplifies the obstacle avoidance process. A solution is designed to solve the trapping problem existing in U-shape obstacle avoidance by an outline memory algorithm. Finally, simulations in three unknown obstacle scenes are carried out to demonstrate the performance of this algorithm, where the obtained obstacle avoidance trajectories are safety, smooth and near-optimal. PMID:29393915

Cross-Cultural Medical Care Training and Education: a National Survey of Pediatric Hematology/Oncology Fellows-in-Training and Fellowship Program Directors.

PubMed

Nageswara Rao, Amulya A; Warad, Deepti M; Weaver, Amy L; Schleck, Cathy D; Rodriguez, Vilmarie

2018-01-27

Pediatric hematologists/oncologists face complex situations such as breaking bad news, treatment/clinical trials discussions, and end-of-life/hospice care. With increasing diversity in patient and physician populations, cultural competency and sensitivity training covering different aspects of pediatric hematology/oncology (PDHO) care can help improve health care delivery and reduce disparities. Though it is considered a required component of fellowship training, there is no clearly defined curriculum meant specifically for PDHO fellows-in-training (PDHO-F). A national online survey of 356 PDHO-F and 67 PDHO program directors (PDHO-PD) was conducted to assess the educational experience, perceptions about identifying barriers including one's own biases and trainee comfort in delivering culturally sensitive care in various PDHO relevant clinical situations. One hundred and eleven (31.2%) PDHO-F and 27 (40.3%) PDHO-PD responded. 30.6% of PDHO-F "strongly agreed/agreed" they received comprehensive cross-cultural communication (CCC) training. The top two teaching methods were faculty role modeling and informal teaching. Majority of CCC training is in medical school or residency and only 10.8% of PDHO-F reported that most of their CCC training was in fellowship. In most clinical situations, there was a modest direct correlation between the fellow's level of agreement that they received comprehensive CCC training and their comfort level. Comfort level with some clinical situations was also significantly different based on year of training. Fellowship training programs should have CCC curricula which use experiential learning models and lay the foundation for promoting cultural awareness, self-reflection, and better patient-physician partnerships which can eventually adapt to and surmount the challenges unique to the physician's chosen field of practice.

Research on Collection System Optimal Design of Wind Farm with Obstacles

NASA Astrophysics Data System (ADS)

Huang, W.; Yan, B. Y.; Tan, R. S.; Liu, L. F.

2017-05-01

To the collection system optimal design of offshore wind farm, the factors considered are not only the reasonable configuration of the cable and switch, but also the influence of the obstacles on the topology design of the offshore wind farm. This paper presents a concrete topology optimization algorithm with obstacles. The minimal area rectangle encasing box of the obstacle is obtained by using the method of minimal area encasing box. Then the optimization algorithm combining the advantages of Dijkstra algorithm and Prim algorithm is used to gain the scheme of avoidance obstacle path planning. Finally a fuzzy comprehensive evaluation model based on the analytic hierarchy process is constructed to compare the performance of the different topologies. Case studies demonstrate the feasibility of the proposed algorithm and model.

Identifying current training provision and future training needs in allergy available for UK general practice trainees: national cross-sectional survey of General Practitioner Specialist Training programme directors.

PubMed

Ellis, Jayne; Rafi, Imran; Smith, Helen; Sheikh, Aziz

2013-03-01

There are ongoing concerns about the quality of care provision for allergy in primary care. To identify current training provision in allergy to GP trainees and to understand how this could be enhanced. A cross-sectional survey of GP Speciality Training (GPST) programme directors was undertaken. Programme directors of the 174 GPST schemes were sent an online questionnaire which was informed by the content of the Royal College of General Practitioners curriculum. Quantitative data were descriptively analysed and a thematic analysis was undertaken of free text responses. We obtained responses from 146 directors representing 106 training programmes. Responses indicated that two-thirds (62%, 95% CI 53.1 to 71.5) of programmes were providing at least some allergy training, with the remaining third stating that they either provided no training or were unsure. Overall, one-third (33%, 95% CI 22.7 to 42.2) of programme directors believed that all the relevant allergy-related curriculum requirements were being met. Where provided, this training was believed to be best for organ-specific allergic disorders but was thought to be poorer for systemic allergic disorders, particularly food allergy where 67% (95% CI 57.5 to 76.5) of respondents indicated that training was poor. There was considerable interest in increasing the allergy training provided, preferably through eLearning modules and problem-based learning materials supported by those with relevant specialist knowledge. This UK-wide survey has identified important gaps in the training of GP trainees in relation to allergy care. Addressing these gaps, particularly in the management of systemic allergic disorders, should help to improve delivery of primary care-based allergy care.

Mental skills training with basic combat training soldiers: A group-randomized trial.

PubMed

Adler, Amy B; Bliese, Paul D; Pickering, Michael A; Hammermeister, Jon; Williams, Jason; Harada, Coreen; Csoka, Louis; Holliday, Bernie; Ohlson, Carl

2015-11-01

Cognitive skills training has been linked to greater skills, self-efficacy, and performance. Although research in a variety of organizational settings has demonstrated training efficacy, few studies have assessed cognitive skills training using rigorous, longitudinal, randomized trials with active controls. The present study examined cognitive skills training in a high-risk occupation by randomizing 48 platoons (N = 2,432 soldiers) in basic combat training to either (a) mental skills training or (b) an active comparison condition (military history). Surveys were conducted at baseline and 3 times across the 10-week course. Multilevel mixed-effects models revealed that soldiers in the mental skills training condition reported greater use of a range of cognitive skills and increased confidence relative to those in the control condition. Soldiers in the mental skills training condition also performed better on obstacle course events, rappelling, physical fitness, and initial weapons qualification scores, although effects were generally moderated by gender and previous experience. Overall, effects were small; however, given the rigor of the design, the findings clearly contribute to the broader literature by providing supporting evidence that cognitive training skills can enhance performance in occupational and sports settings. Future research should address gender and experience to determine the need for targeting such training appropriately. (c) 2015 APA, all rights reserved).

Counteracting Obstacles with Optimistic Predictions

ERIC Educational Resources Information Center

Zhang, Ying; Fishbach, Ayelet

2010-01-01

This research tested for counteractive optimism: a self-control strategy of generating optimistic predictions of future goal attainment in order to overcome anticipated obstacles in goal pursuit. In support of the counteractive optimism model, participants in 5 studies predicted better performance, more time invested in goal activities, and lower…

Getting to Darwin: Obstacles to Accepting Evolution by Natural Selection

ERIC Educational Resources Information Center

Thagard, Paul; Findlay, Scott

2010-01-01

Darwin's theory of evolution by natural selection is central to modern biology, but is resisted by many people. This paper discusses the major psychological obstacles to accepting Darwin's theory. Cognitive obstacles to adopting evolution by natural selection include conceptual difficulties, methodological issues, and coherence problems that…

Development Administration: Obstacles, Theories and Implications for Planning. IIEP Occasional Papers No. 2.

ERIC Educational Resources Information Center

Rodman, Peter W.

In developing countries, public administration is hampered by a number of obstacles foreign to large industrialized nations. Some of these obstacles are shortages of tools and skilled personnel, outmoded organizational structures, political competition, and cultural and attitudinal barriers. The administrative obstacles and their…

Nonlinear water waves generated by impulsive motion of submerged obstacle

NASA Astrophysics Data System (ADS)

Makarenko, N.; Kostikov, V.

2012-04-01

The fully nonlinear problem on generation of unsteady water waves by impulsively moving obstacle is studied analytically. The method involves the reduction of basic Euler equations to the integral-differential system for the wave elevation together with normal and tangential fluid velocities at the free surface. Exact model equations are derived in explicit form when the isolated obstacle is presented by totally submerged circular- or elliptic cylinder. Small-time asymptotic solution is constructed for the cylinder which starts moving with constant acceleration from rest. It is demonstrated that the leading-order solution terms describe several wave regimes such as the formation of non-stationary splash jets by vertical rising or vertical submersion of the obstacle, as well as the generation of diverging waves by horizontal- and combined motion of the obstacle under free surface. This work was supported by RFBR (grant No 10-01-00447) and by Research Program of the Russian Government (grant No 11.G34.31.0035).

Wide-Baseline Stereo-Based Obstacle Mapping for Unmanned Surface Vehicles

PubMed Central

Mou, Xiaozheng; Wang, Han

2018-01-01

This paper proposes a wide-baseline stereo-based static obstacle mapping approach for unmanned surface vehicles (USVs). The proposed approach eliminates the complicated calibration work and the bulky rig in our previous binocular stereo system, and raises the ranging ability from 500 to 1000 m with a even larger baseline obtained from the motion of USVs. Integrating a monocular camera with GPS and compass information in this proposed system, the world locations of the detected static obstacles are reconstructed while the USV is traveling, and an obstacle map is then built. To achieve more accurate and robust performance, multiple pairs of frames are leveraged to synthesize the final reconstruction results in a weighting model. Experimental results based on our own dataset demonstrate the high efficiency of our system. To the best of our knowledge, we are the first to address the task of wide-baseline stereo-based obstacle mapping in a maritime environment. PMID:29617293

Autonomous dynamic obstacle avoidance for bacteria-powered microrobots (BPMs) with modified vector field histogram.

PubMed

Kim, Hoyeon; Cheang, U Kei; Kim, Min Jun

2017-01-01

In order to broaden the use of microrobots in practical fields, autonomous control algorithms such as obstacle avoidance must be further developed. However, most previous studies of microrobots used manual motion control to navigate past tight spaces and obstacles while very few studies demonstrated the use of autonomous motion. In this paper, we demonstrated a dynamic obstacle avoidance algorithm for bacteria-powered microrobots (BPMs) using electric field in fluidic environments. A BPM consists of an artificial body, which is made of SU-8, and a high dense layer of harnessed bacteria. BPMs can be controlled using externally applied electric fields due to the electrokinetic property of bacteria. For developing dynamic obstacle avoidance for BPMs, a kinematic model of BPMs was utilized to prevent collision and a finite element model was used to characteristic the deformation of an electric field near the obstacle walls. In order to avoid fast moving obstacles, we modified our previously static obstacle avoidance approach using a modified vector field histogram (VFH) method. To validate the advanced algorithm in experiments, magnetically controlled moving obstacles were used to intercept the BPMs as the BPMs move from the initial position to final position. The algorithm was able to successfully guide the BPMs to reach their respective goal positions while avoiding the dynamic obstacles.

Training Characteristics During Pregnancy and Postpartum in the World's Most Successful Cross Country Skier.

PubMed

Solli, Guro S; Sandbakk, Øyvind

2018-01-01

This case-study investigated the training characteristics, physiological capacity, and body composition of the world's most successful cross country skier during the 40-week pregnancy, and the 61-week postpartum. Training data was systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and mode (running, cycling, and skiing/roller skiing). The training volume [mean ± standard deviation (median)] during pregnancy was 12.9 ± 7.3(10.0) h/week in the first- (weeks 1-12), 18.3 ± 2.9(18.0) h/week in the second- (weeks 13-28), and 8.8 ± 4.4(9.6) h/week in the third trimester (weeks 29-40). Endurance training time was distributed into 10.9 ± 6.2(9.9), 15.2 ± 2.3(15.6), and 7.6 ± 3.8(7.9) LIT and 0.4 ± 0.5(0.0), 1.3 ± 0.4(1.4), and 0.7 ± 0.6(0.8) h/week MIT during the three trimesters. Only 2.2 h of HIT was performed during the entire pregnancy. During the first two trimesters, the distribution of exercise modes were approximately the same as pre-pregnancy, but the amount of running was reduced during the third trimester. Training volume during the postpartum periods 1-4 was 6.6 ± 3.8(7.1) (PP1; weeks 1-6), 14.1 ± 3.4(14.3) (PP2; weeks 7-12), 10.6 ± 3.8(10.4) (PP3; weeks 13-18), and 13.6 ± 4.1(14.5) h/week (PP4; weeks 19-24), respectively. Training during PP3 and PP4 was interfered with two fractions in the sacrum, leading to decreased amount of running and MIT/HIT, compensated by increased amounts of cycling. Thereafter, training volume progressively approached the pre-pregnancy values, being 18.0 ± 3.9(18.7) h/week during the general preparation- (weeks 25-44), 17.6 ± 4.4(17.3) h/week during the specific preparation- (weeks 45-53), and 16.9 ± 3.5(17.2) h/week during the competition period (CP; weeks 54-61) leading up to the subsequent world championship. The oxygen uptake at the estimated lactate threshold (LT) decreased to 90% of pre-pregnancy values in the second trimester

Cost of treatment: The single biggest obstacle to HIV/AIDS treatment adherence in lower-middle class patients in Mumbai, India.

PubMed

Naik, Eknath; Casanas, Beata; Pazare, Amar; Wabale, Gauri; Sinnott, John; Salihu, Hamisu

2009-01-01

This study analyzes the social, economic and behavioral factors most frequently associated with adherence to Highly Active Antiretroviral Treatment (HAART) in urban India. Data was collected in a metropolitan teaching hospital in Mumbai using a cross-sectional survey design. Face-to-face interviews were conducted with 152 patients. The semistructured survey included both open and closed ended questions on socio-demographic, economic and behavioral factors. Factors affecting treatment adherence were analyzed. The median age of patients was 40.5 years, 73% were males and all were heterosexual. Patients had been given ART from six months to five years (median is equal to 3.5). Ninety per cent lived at home and commuted to the clinic by bus or train. Behaviorally, 37% were sexually active, but only 55% used condoms. In assessing adherence, income, education, knowledge of their drugs, transportation, side effects, cost of treatment, distance from clinic and personal clinic satisfaction were analyzed. We found that 75% of patients reported cost of HAART to be the single greatest obstacle to adherence (p less than 0.01). Additionally, those claiming knowledge of their drugs were 2.3 times more likely to be adherent (p less than 0.03), while those who abused drugs or alcohol were 53% less likely to be adherent (p less than 0.03). There was no correlation with other factors. Our study population was representative of the lower middle class of India. It found that an educated, employed group considered the cost of treatment to be a significant obstacle for successful therapy. Additionally, it showed a significant increase in adherence when patients had knowledge of their HAART medications. Therefore, reducing the cost of medication as well as teaching about antiretroviral medications are both likely to improve adherence.

Community College Workforce Training Programs: Expanding the Mission To Meet Critical Needs.

ERIC Educational Resources Information Center

Beckman, Brenda Marshall; Doucette, Don

1993-01-01

In fall 1992, the League for Innovation in the Community College conducted a survey of 1,042 community colleges to determine the extent and nature of their involvement in workforce training programs, the types of companies served, funding mechanisms, and perceived obstacles to providing effective training. Study findings, based on a 73.2% response…

Workarounds and obstacles: unexpected source of innovation.

PubMed

Lalley, Cathy

2014-01-01

Nurse leaders are aware that nurses are finding ways to adapt health information technology to patient care activities. Previous literature has presented nurses' response to technology obstacles as a work-around, characterized as a negative behavior. Using narrative inquiry, this article examines 9 direct care nurses' interactions on a medical/surgical/telemetry unit. Specifically, nurses' encounters with technology obstacles will be addressed from a complexity science perspective. Four support staff including the clinical nurse manager, pharmacist, quality nurse, and project manager who is also a nurse were interviewed as part of data collection. Complexity science provides nurse leaders' insight into nurses' behavior where outcomes emerge from tensions in the environment through multidirectional and self-organizing interactions. Innovation was found when nurses responded to health information technology obstacles with self-organizing interactions, sensitivity to initial conditions, and multidirectionality. Their actions were also influenced by many sets of rules. Nurses self-organized with coworkers to find better ways to deliver care to patients when using technology. Opportunities exist for nurse leaders to facilitate interactions among nurses and other members of the organization to realize better use of health information technology that improves the patient experience.

Malaria: Obstacles and Opportunities.

DTIC Science & Technology

1991-01-01

SUBTITLE S. FUNDING NUMBERS Malaria: Obstacles and Opportunities 89PP9965 62770A 6. AUTHOR(S) 3MI62770A870 AN DA3 46085 Arthur Dennis Long 7. PERFORMING ...ORGANIZATION NAME(S) AND ADORESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Agency for International Development New State Office Building Washignton...Hygiene and Pub- lic Health, Baltimore. \\Maryland JACQUELINE A. CATTANI. Secretary, Steering Committee of the Scientific Working Group on Applied

Integrated surgical academic training in the UK: a cross-sectional survey.

PubMed

Blencowe, Natalie S; Glasbey, James C; McElnay, Philip J; Bhangu, Aneel; Gokani, Vimal J; Harries, Rhiannon L

2017-10-01

This study aimed to explore variations in the provision of integrated academic surgical training across the UK. This is an online cross-sectional survey (consisting of 44 items with a range of free-text, binomial and 5-point Likert scale responses) developed by the Association of Surgeons in Training. A self-reported survey instrument was distributed to academic surgical trainees across the UK (n=276). 143 (51.9%) responses were received (81% male, median age: 34 years), spanning all UK regions and surgical specialties. Of the 143 trainees, 29 were core trainees (20.3%), 99 were specialty trainees (69.2%) and 15 (10.5%) described themselves as research fellows. The structure of academic training varied considerably, with under a third of trainees receiving guaranteed protected time for research. Despite this, however, 53.1% of the respondents reported to be satisfied with how their academic training was organised. Covering clinical duties during academic time occurred commonly (72.7%). Although most trainees (n=88, 61.5%) met with their academic supervisor at least once a month, six (4.2%) never had an academic supervisory meeting. Most trainees (n=90, 62.9%) occupied a full-time rota slot and only 9.1% (n=13) described their role as 'supernumerary'. Although 58.7% (n=84) of the trainees were satisfied with their clinical competence, 37.8% (n=54) felt that clinical time focused more on service provision than the acquisition of technical skills. 58 (40.6%) had experienced some form of negative sentiment relating to their status as an academic trainee. Integrated academic training presents unique challenges and opportunities within surgery. This survey has identified variation in the quality of current programmes, meaning that the future provision of integrated surgical academic training should be carefully considered. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is

Learning piano melodies in visuo-motor or audio-motor training conditions and the neural correlates of their cross-modal transfer.

PubMed

Engel, Annerose; Bangert, Marc; Horbank, David; Hijmans, Brenda S; Wilkens, Katharina; Keller, Peter E; Keysers, Christian

2012-11-01

To investigate the cross-modal transfer of movement patterns necessary to perform melodies on the piano, 22 non-musicians learned to play short sequences on a piano keyboard by (1) merely listening and replaying (vision of own fingers occluded) or (2) merely observing silent finger movements and replaying (on a silent keyboard). After training, participants recognized with above chance accuracy (1) audio-motor learned sequences upon visual presentation (89±17%), and (2) visuo-motor learned sequences upon auditory presentation (77±22%). The recognition rates for visual presentation significantly exceeded those for auditory presentation (p<.05). fMRI revealed that observing finger movements corresponding to audio-motor trained melodies is associated with stronger activation in the left rolandic operculum than observing untrained sequences. This region was also involved in silent execution of sequences, suggesting that a link to motor representations may play a role in cross-modal transfer from audio-motor training condition to visual recognition. No significant differences in brain activity were found during listening to visuo-motor trained compared to untrained melodies. Cross-modal transfer was stronger from the audio-motor training condition to visual recognition and this is discussed in relation to the fact that non-musicians are familiar with how their finger movements look (motor-to-vision transformation), but not with how they sound on a piano (motor-to-sound transformation). Copyright © 2012 Elsevier Inc. All rights reserved.

On the debate about teleology in biology: the notion of "teleological obstacle".

PubMed

Ribeiro, Manuel Gustavo Leitão; Larentis, Ariane Leites; Caldas, Lúcio Ayres; Garcia, Tomás Coelho; Terra, Letícia Labati; Herbst, Marcelo Hawrylak; Almeida, Rodrigo Volcan

2015-12-01

Among the epistemological obstacles described by Gaston Bachelard, we contend that unitary and pragmatic knowledge is correlated to the teleological categories of Ernst Mayr and is the basis for prevailing debate on the notion of "function" in biology. Given the proximity of the aspects highlighted by these authors, we propose to associate the role of teleological thinking in biology and the notion of unitary and pragmatic knowledge as an obstacle to scientific knowledge. Thus, teleological thinking persists acting as an epistemological obstacle in biology, according to Bachelardian terminology. Our investigation led us to formulate the "teleological obstacle," which we consider important for the future of biology and possibly other sciences.

Getting to Darwin: Obstacles to Accepting Evolution by Natural Selection

NASA Astrophysics Data System (ADS)

Thagard, Paul; Findlay, Scott

2010-06-01

Darwin’s theory of evolution by natural selection is central to modern biology, but is resisted by many people. This paper discusses the major psychological obstacles to accepting Darwin’s theory. Cognitive obstacles to adopting evolution by natural selection include conceptual difficulties, methodological issues, and coherence problems that derive from the intuitiveness of alternative theories. The main emotional obstacles to accepting evolution are its apparent conflict with valued beliefs about God, souls, and morality. We draw on the philosophy of science and on a psychological theory of cognitive and emotional belief revision to make suggestions about what can be done to improve acceptance of Darwinian ideas.

A novel artificial immune algorithm for spatial clustering with obstacle constraint and its applications.

PubMed

Sun, Liping; Luo, Yonglong; Ding, Xintao; Zhang, Ji

2014-01-01

An important component of a spatial clustering algorithm is the distance measure between sample points in object space. In this paper, the traditional Euclidean distance measure is replaced with innovative obstacle distance measure for spatial clustering under obstacle constraints. Firstly, we present a path searching algorithm to approximate the obstacle distance between two points for dealing with obstacles and facilitators. Taking obstacle distance as similarity metric, we subsequently propose the artificial immune clustering with obstacle entity (AICOE) algorithm for clustering spatial point data in the presence of obstacles and facilitators. Finally, the paper presents a comparative analysis of AICOE algorithm and the classical clustering algorithms. Our clustering model based on artificial immune system is also applied to the case of public facility location problem in order to establish the practical applicability of our approach. By using the clone selection principle and updating the cluster centers based on the elite antibodies, the AICOE algorithm is able to achieve the global optimum and better clustering effect.

Autonomous dynamic obstacle avoidance for bacteria-powered microrobots (BPMs) with modified vector field histogram

PubMed Central

Kim, Hoyeon; Cheang, U. Kei

2017-01-01

In order to broaden the use of microrobots in practical fields, autonomous control algorithms such as obstacle avoidance must be further developed. However, most previous studies of microrobots used manual motion control to navigate past tight spaces and obstacles while very few studies demonstrated the use of autonomous motion. In this paper, we demonstrated a dynamic obstacle avoidance algorithm for bacteria-powered microrobots (BPMs) using electric field in fluidic environments. A BPM consists of an artificial body, which is made of SU-8, and a high dense layer of harnessed bacteria. BPMs can be controlled using externally applied electric fields due to the electrokinetic property of bacteria. For developing dynamic obstacle avoidance for BPMs, a kinematic model of BPMs was utilized to prevent collision and a finite element model was used to characteristic the deformation of an electric field near the obstacle walls. In order to avoid fast moving obstacles, we modified our previously static obstacle avoidance approach using a modified vector field histogram (VFH) method. To validate the advanced algorithm in experiments, magnetically controlled moving obstacles were used to intercept the BPMs as the BPMs move from the initial position to final position. The algorithm was able to successfully guide the BPMs to reach their respective goal positions while avoiding the dynamic obstacles. PMID:29020016

A method of real-time detection for distant moving obstacles by monocular vision

NASA Astrophysics Data System (ADS)

Jia, Bao-zhi; Zhu, Ming

2013-12-01

In this paper, we propose an approach for detection of distant moving obstacles like cars and bicycles by a monocular camera to cooperate with ultrasonic sensors in low-cost condition. We are aiming at detecting distant obstacles that move toward our autonomous navigation car in order to give alarm and keep away from them. Method of frame differencing is applied to find obstacles after compensation of camera's ego-motion. Meanwhile, each obstacle is separated from others in an independent area and given a confidence level to indicate whether it is coming closer. The results on an open dataset and our own autonomous navigation car have proved that the method is effective for detection of distant moving obstacles in real-time.

Training-related and competition-related risk factors for respiratory tract and gastrointestinal infections in elite cross-country skiers.

PubMed

Svendsen, Ida S; Taylor, Ian M; Tønnessen, Espen; Bahr, Roald; Gleeson, Michael

2016-07-01

To examine symptoms indicative of respiratory tract and gastrointestinal infections and determine risk factors for such symptoms in elite cross-country skiers. Self-reported training and symptom data for 37 elite cross-country skiers from 2007 to 2015 were analysed using multilevel logistic regression equations with symptom incidence and duration as outcome variables, and sex, performance level, season, competition, air travel, altitude exposure and training characteristics as independent variables. Data for 7016 person-weeks were analysed, including 464 self-reported infection events and 110 959 h of training. Athletes reported median (range) 3 (1-7) respiratory tract and/or gastrointestinal events per year, with symptoms lasting 5 (1-24) days. During the winter, symptoms occurred more frequently (OR 2.09, p<0.001) and lasted longer (b=0.043, p<0.001) compared with summer. Competition and air travel increased the risk of symptoms, with ORs of 2.93 (95% CI 2.24 to 3.83) and 4.94 (95% CI 3.74 to 6.53), respectively (p<0.001). Athletes with higher training monotony had lower risk of symptoms (OR 0.87 (95% CI 0.73 to 0.99), p<0.05). Other training variables were not associated with symptoms. Athletes who had won an Olympic/World Championship medal reported shorter symptom duration compared with less successful athletes (b=-0.019, p<0.05) resulting in significantly fewer symptomatic days/year (14 (6-29) vs 22 (8-43) days/year). Air travel and competition are major risk factors for acute respiratory tract and gastrointestinal symptoms in this population. Athletes who have large fluctuations in training load experience such symptoms more frequently. Shorter duration of symptoms appears to be associated with success in cross-country skiing. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Laparoscopic simulation training in gynaecology: Current provision and staff attitudes - a cross-sectional survey.

PubMed

Burden, Christy; Fox, Robert; Hinshaw, Kim; Draycott, Timothy J; James, Mark

2016-01-01

The objectives of this study were to explore current provision of laparoscopic simulation training, and to determine attitudes of trainers and trainees to the role of simulators in surgical training across the UK. An anonymous cross-sectional survey with cluster sampling was developed and circulated. All Royal College of Obstetricians and Gynaecologists (RCOG) Training Programme Directors (TPD), College Tutors (RCT) and Trainee representatives (TR) across the UK were invited to participate. One hundred and ninety-six obstetricians and gynaecologists participated. Sixty-three percent of hospitals had at least one box trainer, and 14.6% had least one virtual-reality simulator. Only 9.3% and 3.6% stated that trainees used a structured curriculum on box and virtual-reality simulators, respectively. Respondents working in a Large/Teaching hospital (p = 0.008) were more likely to agree that simulators enhance surgical training. Eighty-nine percent agreed that simulators improve the quality of training, and should be mandatory or desirable for junior trainees. Consultants (p = 0.003) and respondents over 40 years (p = 0.011) were more likely to hold that a simulation test should be undertaken before live operation. Our data demonstrated, therefore, that availability of laparoscopic simulators is inconsistent, with limited use of mandatory structured curricula. In contrast, both trainers and trainees recognise a need for greater use of laparoscopic simulation for surgical training.

Assisting the visually impaired: obstacle detection and warning system by acoustic feedback.

PubMed

Rodríguez, Alberto; Yebes, J Javier; Alcantarilla, Pablo F; Bergasa, Luis M; Almazán, Javier; Cela, Andrés

2012-12-17

The aim of this article is focused on the design of an obstacle detection system for assisting visually impaired people. A dense disparity map is computed from the images of a stereo camera carried by the user. By using the dense disparity map, potential obstacles can be detected in 3D in indoor and outdoor scenarios. A ground plane estimation algorithm based on RANSAC plus filtering techniques allows the robust detection of the ground in every frame. A polar grid representation is proposed to account for the potential obstacles in the scene. The design is completed with acoustic feedback to assist visually impaired users while approaching obstacles. Beep sounds with different frequencies and repetitions inform the user about the presence of obstacles. Audio bone conducting technology is employed to play these sounds without interrupting the visually impaired user from hearing other important sounds from its local environment. A user study participated by four visually impaired volunteers supports the proposed system.

Assisting the Visually Impaired: Obstacle Detection and Warning System by Acoustic Feedback

PubMed Central

Rodríguez, Alberto; Yebes, J. Javier; Alcantarilla, Pablo F.; Bergasa, Luis M.; Almazán, Javier; Cela, Andrés

2012-01-01

The aim of this article is focused on the design of an obstacle detection system for assisting visually impaired people. A dense disparity map is computed from the images of a stereo camera carried by the user. By using the dense disparity map, potential obstacles can be detected in 3D in indoor and outdoor scenarios. A ground plane estimation algorithm based on RANSAC plus filtering techniques allows the robust detection of the ground in every frame. A polar grid representation is proposed to account for the potential obstacles in the scene. The design is completed with acoustic feedback to assist visually impaired users while approaching obstacles. Beep sounds with different frequencies and repetitions inform the user about the presence of obstacles. Audio bone conducting technology is employed to play these sounds without interrupting the visually impaired user from hearing other important sounds from its local environment. A user study participated by four visually impaired volunteers supports the proposed system. PMID:23247413

Collective rotations of active particles interacting with obstacles

NASA Astrophysics Data System (ADS)

Mokhtari, Zahra; Aspelmeier, Timo; Zippelius, Annette

2017-10-01

We consider active particles in a heterogeneous medium, modeled by static, random obstacles. In accordance with the known tendency of active particles to cluster, we observe accumulation and crystallization of active particles around the obstacles which serve as nucleation sites. In the limit of high activity, the crystals start to rotate spontaneously, resembling a rotating rigid body. We trace the occurrence of these oscillations to the enhanced attraction of particles whose orientation points along the rotational velocity as compared to those whose orientation points in the opposite direction.

[Educational obstacles in the everyday living of the nurse teacher's pedagogical practice].

PubMed

Rodrigues, Malvina Thaís Pacheco; Mendes Sobrinho, José Augusto de Carvalho

2008-01-01

University teaching emerges as a theme frequently discussed in the educational scene. This article aims to investigate the educational obstacles emerging in the everyday living of the pedagogical practice of the nurse teacher from the Nursing Graduation Course at UEPSI, wishing to subsidize the elaboration of proposals for overcoming of these obstacles. It is a study of qualitative approach with data collection, questionnaire and semi-structured interview and data analysis through content analysis. According to the analysis, it is clear that the educational obstacles relate to the teacher person, to the students and to the institution. Thus, an establishment of a continuing education program in the action-reflection-action perspective is proposed as a way of overcoming the obstacles.

3D-Sonification for Obstacle Avoidance in Brownout Conditions

NASA Technical Reports Server (NTRS)

Godfroy-Cooper, M.; Miller, J. D.; Szoboszlay, Z.; Wenzel, E. M.

2017-01-01

Helicopter brownout is a phenomenon that occurs when making landing approaches in dusty environments, whereby sand or dust particles become swept up in the rotor outwash. Brownout is characterized by partial or total obscuration of the terrain, which degrades visual cues necessary for hovering and safe landing. Furthermore, the motion of the dust cloud produced during brownout can lead to the pilot experiencing motion cue anomalies such as vection illusions. In this context, the stability and guidance control functions can be intermittently or continuously degraded, potentially leading to undetected surface hazards and obstacles as well as unnoticed drift. Safe and controlled landing in brownout can be achieved using an integrated presentation of LADAR and RADAR imagery and aircraft state symbology. However, though detected by the LADAR and displayed on the sensor image, small obstacles can be difficult to discern from the background so that changes in obstacle elevation may go unnoticed. Moreover, pilot workload associated with tracking the displayed symbology is often so high that the pilot cannot give sufficient attention to the LADAR/RADAR image. This paper documents a simulation evaluating the use of 3D auditory cueing for obstacle avoidance in brownout as a replacement for or compliment to LADAR/RADAR imagery.

Effects of buried obstacles on penetration resistance in cohesionless soils

NASA Technical Reports Server (NTRS)

Deluca, E. W.; Carrasco, L. H.

1972-01-01

Recent experiments concerning penetration of cohesionless soils in special molds that include solid obstacles embedded within the soil matrix are reported. The relative effects of these obstacles with respect to the soil properties of relative density, texture, and gradation are also discussed. Because lunar soil is fairly cohesionless, special attention was given to the Apollo lunar simulant, AP-12.

Online optimal obstacle avoidance for rotary-wing autonomous unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Kang, Keeryun

This thesis presents an integrated framework for online obstacle avoidance of rotary-wing unmanned aerial vehicles (UAVs), which can provide UAVs an obstacle field navigation capability in a partially or completely unknown obstacle-rich environment. The framework is composed of a LIDAR interface, a local obstacle grid generation, a receding horizon (RH) trajectory optimizer, a global shortest path search algorithm, and a climb rate limit detection logic. The key feature of the framework is the use of an optimization-based trajectory generation in which the obstacle avoidance problem is formulated as a nonlinear trajectory optimization problem with state and input constraints over the finite range of the sensor. This local trajectory optimization is combined with a global path search algorithm which provides a useful initial guess to the nonlinear optimization solver. Optimization is the natural process of finding the best trajectory that is dynamically feasible, safe within the vehicle's flight envelope, and collision-free at the same time. The optimal trajectory is continuously updated in real time by the numerical optimization solver, Nonlinear Trajectory Generation (NTG), which is a direct solver based on the spline approximation of trajectory for dynamically flat systems. In fact, the overall approach of this thesis to finding the optimal trajectory is similar to the model predictive control (MPC) or the receding horizon control (RHC), except that this thesis followed a two-layer design; thus, the optimal solution works as a guidance command to be followed by the controller of the vehicle. The framework is implemented in a real-time simulation environment, the Georgia Tech UAV Simulation Tool (GUST), and integrated in the onboard software of the rotary-wing UAV test-bed at Georgia Tech. Initially, the 2D vertical avoidance capability of real obstacles was tested in flight. The flight test evaluations were extended to the benchmark tests for 3D avoidance

Training in urological robotic surgery. Future perspectives.

PubMed

El Sherbiny, Ahmed; Eissa, Ahmed; Ghaith, Ahmed; Morini, Elena; Marzotta, Lucilla; Sighinolfi, Maria Chiara; Micali, Salvatore; Bianchi, Giampaolo; Rocco, Bernardo

2018-01-01

As robotics are becoming more integrated into the medical field, robotic training is becoming more crucial in order to overcome the lack of experienced robotic surgeons. However, there are several obstacles facing the development of robotic training programs like the high cost of training and the increased operative time during the initial period of the learning curve, which, in turn increase the operative cost. Robotic-assisted laparoscopic prostatectomy is the most commonly performed robotic surgery. Moreover, robotic surgery is becoming more popular among urologic oncologists and pediatric urologists. The need for a standardized and validated robotic training curriculum was growing along with the increased number of urologic centers and institutes adopting the robotic technology. Robotic training includes proctorship, mentorship or fellowship, telementoring, simulators and video training. In this chapter, we are going to discuss the different training methods, how to evaluate robotic skills, the available robotic training curriculum, and the future perspectives.

What are the Facilitators and Obstacles to Participation in Workplace Team Sport? A Qualitative Study

PubMed Central

Brinkley, Andrew; Freeman, Josie; McDermott, Hilary; Munir, Fehmidah

2017-01-01

Working age adults are failing to meet physical activity recommendations. Inactive behaviours are increasing costs for diminished individual and organisational health. The workplace is a priority setting to promote physical activity, however there is a lack of evidence about why some employees choose to participate in novel workplace activities, such as team sport, whilst others do not. The aim of this study was to explore the complexity of facilitators and obstacles associated with participation in workplace team sport. Twenty-nine semi-structured face-to-face and telephone interviews were conducted with office workers (58% female) (36 ± 7.71) from manufacturing, public services, and educational services. Data was analysed through template analysis. Five sub-level (i.e., intrapersonal, interpersonal, organisational, community and societal influences) facilitate participation or create obstacles for participants. Participants were challenged by a lack of competence, self-efficacy, negative sporting ideals and amotivation. Unhealthy competition, an unstable work-life balance and unsupportive colleagues created obstacles to participation. An unsupportive organisation and workplace culture placed demands on workplace champions, funding, facilities and communication. Healthy competitions, high perceptions of competence and self-efficacy, and being motivated autonomously enabled participation. Further, relatedness and social support created a physical activity culture where flexible working was encouraged and team sport was promoted in accessible locations within the organisation. Researchers should consider accounting for complexity of these influences. A participatory approach may tailor interventions to individual organisations and the employees that work within them. Interventions whereby autonomy, competence and relatedness are supported are recommended. This may be achieved by adapting sports and training workplace champions. PMID:29922705

Planning and assessing a cross-training initiative with multi-skilled employees.

PubMed

Wermers, M A; Dagnillo, R; Glenn, R; Macfarlane, R; St Clair, V; Scott, D

1996-06-01

An improvement initiative begun by nurses at Parkview Episcopal Medical Center (Pueblo, Colo) to develop patient-focused care delivered by multiskilled workers followed a quality improvement methodology. Implementation of the new care delivery system on a model unit--2 South--provided the opportunity to plan, analyze data, and make changes as appropriate. Parkview's indoctrination of the teachings of W. Edwards Deming has helped leaders and staff realize the integral role of training in improvement activities. In his 14 points, Deming emphasizes the importance of employee education and of the employee having a clear understanding of his or her job. The time and money put into up-front education should help ensure the long-term success of this initiative. DEFINING THE CAREPARTNER: Three new multi-skilled positions were developed on 2 South--a Personal CarePartner, a Business CarePartner, and a Clinical CarePartner. By cross-training each of these roles to perform duties formerly done by centralized departments, 2 South was able to cut costs and time while ensuring quality care. TRAINING THE CAREPARTNER: An internally developed training program provided the new CarePartners with up-front education to prepare them to deliver patient-centered care. 2 South has experienced drops in patient falls and medication errors--areas that are often negatively affected when multi-skilled programs are instituted. Patient and physician surveys have shown increased satisfaction with care provided on the unit. The increased efficiency of the model unit has produced these outcomes while cutting costs substantially. The interdisciplinary team coordinating the improvement project learned many lessons in the process, including the importance of communication, education, and a sense of humor.

Explosion hazards of LPG-air mixtures in vented enclosure with obstacles.

PubMed

Zhang, Qi; Wang, Yaxing; Lian, Zhen

2017-07-15

Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent. Dynamic pressures produced by an indoor LPG explosion reach their maximum always beyond the vent no matter obstacles are present or not in the enclosure. A LPG explosion in a vented enclosure with built-in obstacles is strong enough to make the brick and mortar wall with a thickness of 370mm damaged. If there is no obstacle in the enclosure, the lower explosion pressure of several kPa can not break the brick and mortar wall with a thickness of 370mm. For a LPG explosion produced in an enclosure with a vent, main hazards, within the vent, are overpressure and high temperature. However main hazards are dynamic pressure, blast wind, and high temperature beyond the vent. Copyright © 2017 Elsevier B.V. All rights reserved.

C1,1 regularity for degenerate elliptic obstacle problems

NASA Astrophysics Data System (ADS)

Daskalopoulos, Panagiota; Feehan, Paul M. N.

2016-03-01

The Heston stochastic volatility process is a degenerate diffusion process where the degeneracy in the diffusion coefficient is proportional to the square root of the distance to the boundary of the half-plane. The generator of this process with killing, called the elliptic Heston operator, is a second-order, degenerate-elliptic partial differential operator, where the degeneracy in the operator symbol is proportional to the distance to the boundary of the half-plane. In mathematical finance, solutions to the obstacle problem for the elliptic Heston operator correspond to value functions for perpetual American-style options on the underlying asset. With the aid of weighted Sobolev spaces and weighted Hölder spaces, we establish the optimal C 1 , 1 regularity (up to the boundary of the half-plane) for solutions to obstacle problems for the elliptic Heston operator when the obstacle functions are sufficiently smooth.

The relationship between quality of work life and location of cross-training among obstetric nurses in urban northeastern Ontario, Canada: A population-based cross sectional study.

PubMed

Nowrouzi, Behdin; Lightfoot, Nancy; Carter, Lorraine; Larivière, Michel; Rukholm, Ellen; Schinke, Robert; Belanger-Gardner, Diane

2015-01-01

The purpose of this mixed methods study was to examine the quality of work life of registered nurses working in obstetrics at 4 hospitals in northeastern Ontario and explore demographic and occupational factors related to nurses' quality of work life (QWL). A stratified random sample of registered nurses (N = 111) selected from the 138 eligible registered nurses (80.4%) of staff in the labor, delivery, recovery, and postpartum areas at the 4 hospitals participated. Logistic regression analyses were used to consider QWL in relation to the following: 1) demographic factors, and 2) stress, employment status and educational attainment. In the logistic regression model, the odds of a higher quality of work life for nurses who were cross trained (nurses who can work across all areas of obstetrical care) were estimated to be 3.82 (odds ratio = 3.82, 95% confidence interval: 1.01-14.5) times the odds of a higher quality of work life for nurses who were not cross trained. This study highlights a relationship between quality of work life and associated factors including location of cross-training among obstetrical nurses in northeastern Ontario. These findings are supported by the qualitative interviews that examine in depth their relationship to QWL. Given the limited number of employment opportunities in the rural and remote regions, it is paramount that employers and employees work closely together in creating positive environments that promote nurses' QWL. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Bi-stability in cooperative transport by ants in the presence of obstacles

PubMed Central

Pinkoviezky, Itai; Feinerman, Ofer

2018-01-01

To cooperatively carry large food items to the nest, individual ants conform their efforts and coordinate their motion. Throughout this expedition, collective motion is driven both by internal interactions between the carrying ants and a response to newly arrived informed ants that orient the cargo towards the nest. During the transport process, the carrying group must overcome obstacles that block their path to the nest. Here, we investigate the dynamics of cooperative transport, when the motion of the ants is frustrated by a linear obstacle that obstructs the motion of the cargo. The obstacle contains a narrow opening that serves as the only available passage to the nest, and through which single ants can pass but not with the cargo. We provide an analytical model for the ant-cargo system in the constrained environment that predicts a bi-stable dynamic behavior between an oscillatory mode of motion along the obstacle and a convergent mode of motion near the opening. Using both experiments and simulations, we show how for small cargo sizes, the system exhibits spontaneous transitions between these two modes of motion due to fluctuations in the applied force on the cargo. The bi-stability provides two possible problem solving strategies for overcoming the obstacle, either by attempting to pass through the opening, or take large excursions to circumvent the obstacle. PMID:29746457

Bi-stability in cooperative transport by ants in the presence of obstacles.

PubMed

Ron, Jonathan E; Pinkoviezky, Itai; Fonio, Ehud; Feinerman, Ofer; Gov, Nir S

2018-05-01

To cooperatively carry large food items to the nest, individual ants conform their efforts and coordinate their motion. Throughout this expedition, collective motion is driven both by internal interactions between the carrying ants and a response to newly arrived informed ants that orient the cargo towards the nest. During the transport process, the carrying group must overcome obstacles that block their path to the nest. Here, we investigate the dynamics of cooperative transport, when the motion of the ants is frustrated by a linear obstacle that obstructs the motion of the cargo. The obstacle contains a narrow opening that serves as the only available passage to the nest, and through which single ants can pass but not with the cargo. We provide an analytical model for the ant-cargo system in the constrained environment that predicts a bi-stable dynamic behavior between an oscillatory mode of motion along the obstacle and a convergent mode of motion near the opening. Using both experiments and simulations, we show how for small cargo sizes, the system exhibits spontaneous transitions between these two modes of motion due to fluctuations in the applied force on the cargo. The bi-stability provides two possible problem solving strategies for overcoming the obstacle, either by attempting to pass through the opening, or take large excursions to circumvent the obstacle.

Mutual Adaptation: Enhancing Longer-Term Sustainability of Cross-Cultural In-Service Teacher Training Initiatives in China

ERIC Educational Resources Information Center

Yan, Chunmei

2008-01-01

This paper reports on a study that examines decisive factors for longer-term sustainability of cross-cultural teacher training initiatives in China. It focuses on teacher trainees' perspectives of a Sino-British adult education English language teaching project based in Central China. Questionnaires and semi-structured interviews were employed to…

Monte Carlo simulations of protein micropatterning in biomembranes: effects of immobile sticky obstacles

NASA Astrophysics Data System (ADS)

Arnold, Andreas M.; Sevcsik, Eva; Schütz, Gerhard J.

2016-09-01

Single molecule trajectories of lipids and proteins can yield valuable information about the nanoscopic organization of the plasma membrane itself. The interpretation of such trajectories, however, is complicated, as the mobility of molecules can be affected by the presence of immobile obstacles, and the transient binding of the tracers to these obstacles. We have previously developed a micropatterning approach that allows for immobilizing a plasma membrane protein and probing the diffusional behavior of a putative interaction partner in living cells. Here, we provide guidelines on how this micropatterning approach can be extended to quantify interaction parameters between plasma membrane constituents in their natural environment. We simulated a patterned membrane system and evaluated the effect of different surface densities of patterned immobile obstacles on the relative mobility as well as the surface density of diffusing tracers. In the case of inert obstacles, the size of the obstacle can be assessed from its surface density at the percolation threshold, which in turn can be extracted from the diffusion behavior of the tracer. For sticky obstacles, 2D dissociation constants can be determined from the tracer diffusion or surface density.

Interactive ESL In-Service Teacher Training via Distance Education.

ERIC Educational Resources Information Center

Power, Michael A.

The Hawaii State Department of Education offers university credit courses in English-as-a-Second-Language (ESL) techniques to all public school teachers, but the scarcity of trainers and the distance between schools and training sites constitute substantial obstacles. With the cooperation of the University of Hawaii's interactive television…

Overcoming an Obstacle in Expanding a UMLS Semantic Type Extent

PubMed Central

Chen, Yan; Gu, Huanying; Perl, Yehoshua; Geller, James

2011-01-01

This paper strives to overcome a major problem encountered by a previous expansion methodology for discovering concepts highly likely to be missing a specific semantic type assignment in the UMLS. This methodology is the basis for an algorithm that presents the discovered concepts to a human auditor for review and possible correction. We analyzed the problem of the previous expansion methodology and discovered that it was due to an obstacle constituted by one or more concepts assigned the UMLS Semantic Network semantic type Classification. A new methodology was designed that bypasses such an obstacle without a combinatorial explosion in the number of concepts presented to the human auditor for review. The new expansion methodology with obstacle avoidance was tested with the semantic type Experimental Model of Disease and found over 500 concepts missed by the previous methodology that are in need of this semantic type assignment. Furthermore, other semantic types suffering from the same major problem were discovered, indicating that the methodology is of more general applicability. The algorithmic discovery of concepts that are likely missing a semantic type assignment is possible even in the face of obstacles, without an explosion in the number of processed concepts. PMID:21925287

Anomalous diffusion due to hindering by mobile obstacles undergoing Brownian motion or Orstein-Ulhenbeck processes.

PubMed

Berry, Hugues; Chaté, Hugues

2014-02-01

In vivo measurements of the passive movements of biomolecules or vesicles in cells consistently report "anomalous diffusion," where mean-squared displacements scale as a power law of time with exponent α<1 (subdiffusion). While the detailed mechanisms causing such behaviors are not always elucidated, movement hindrance by obstacles is often invoked. However, our understanding of how hindered diffusion leads to subdiffusion is based on diffusion amidst randomly located immobile obstacles. Here, we have used Monte Carlo simulations to investigate transient subdiffusion due to mobile obstacles with various modes of mobility. Our simulations confirm that the anomalous regimes rapidly disappear when the obstacles move by Brownian motion. By contrast, mobile obstacles with more confined displacements, e.g., Orstein-Ulhenbeck motion, are shown to preserve subdiffusive regimes. The mean-squared displacement of tracked protein displays convincing power laws with anomalous exponent α that varies with the density of Orstein-Ulhenbeck (OU) obstacles or the relaxation time scale of the OU process. In particular, some of the values we observed are significantly below the universal value predicted for immobile obstacles in two dimensions. Therefore, our results show that subdiffusion due to mobile obstacles with OU type of motion may account for the large variation range exhibited by experimental measurements in living cells and may explain that some experimental estimates are below the universal value predicted for immobile obstacles.

Atmospheric dispersion of a heavier-than-air gas near a two-dimensional obstacle

NASA Astrophysics Data System (ADS)

Sutton, S. B.; Brandt, H.; White, B. R.

1986-04-01

Flow over a two-dimensional obstacle and dispersion of a heavier-than-air gas near the obstacle were studied. Two species, one representing air and the other representing the heavier-than-air gas were treated. Equations for mass and momentum were cast in mass-averaged form, with turbulent Reynolds stresses and mass fluxes modeled using eddy-viscosity and diffusivity hypotheses. A two-equation k-ɛ turbulence model was used to determine the effective turbulent viscosity. Streamline curvature and buoyancy corrections were added to the basic turbulence formulation. The model equations were solved using finite difference techniques. An alternating-direction-implicit (ADI) technique was used to solve the parabolic transport equations and a direct matrix solver was used to solve the elliptic pressure equation. Mesh sensitivities were investigated to determine the optimum mesh requirements for the final calculations. It was concluded that at least 10 grid spaces were required across the obstacle width and 15 across the obstacle height to obtain valid solutions. A non-uniform mesh was used to concentrate the grid points at the top of the obstacle. Experimental measurements were made with air flow over a 7.6 by 7.6 cm obstacle in a boundary-layer wind tunnel. Smoke visualization revealed a low-frequency oscillation of the bubble downstream of the obstacle. Hot-wire anemometer data are presented for the mean velocity and turbulent kinetic energy at the mid-plane of the obstacle and the mid-plane of the downstream recirculation bubble. A single hot-wire probe was found to be suitable for determining mean streamwise velocities with an accuracy of 11 %. The downstream recirculation bubble was unsteady and had a length range from 3 to 8 obstacle lengths. The experimental results for flow over the obstacle were compared with numerical calculations to validate the numerical solution procedure. A sensitivity study on the effect of curvature correction and variation of turbulence

Determinants of Motion Sickness in Tilting Trains: Coriolis/Cross-Coupling Stimuli and Tilt Delay

PubMed Central

Bertolini, Giovanni; Durmaz, Meek Angela; Ferrari, Kim; Küffer, Alexander; Lambert, Charlotte; Straumann, Dominik

2017-01-01

Faster trains require tilting of the cars to counterbalance the centrifugal forces during curves. Motion sensitive passengers, however, complain of discomfort and overt motion sickness. A recent study comparing different control systems in a tilting train, suggested that the delay of car tilts relative to the curve of the track contributes to motion sickness. Other aspects of the motion stimuli, like the lateral accelerations and the car jitters, differed between the tested conditions and prevented a final conclusion on the role of tilt delay. Nineteen subjects were tested on a motorized 3D turntable that simulated the roll tilts during yaw rotations experienced on a tilting train, isolating them from other motion components. Each session was composed of two consecutive series of 12 ideal curves that were defined on the bases of recordings during an actual train ride. The simulated car tilts started either at the beginning of the curve acceleration phase (no-delay condition) or with 3 s of delay (delay condition). Motion sickness was self-assessed by each subject at the end of each series using an analog motion sickness scale. All subjects were tested in both conditions. Significant increases of motion sickness occurred after the first sequence of 12 curves in the delay condition, but not in the no-delay condition. This increase correlated with the sensitivity of motion sickness, which was self-assessed by each subject before the experiment. The second sequence of curve did not lead to a significant further increase of motion sickness in any condition. Our results demonstrate that, even if the speed and amplitude are as low as those experienced on tilting trains, a series of roll tilts with a delay relative to the horizontal rotations, isolated from other motion stimuli occurring during a travel, generate Coriolis/cross-coupling stimulations sufficient to rapidly induce motion sickness in sensitive individuals. The strength and the rapid onset of the motion

Leadership, collaboration, and effective training principles and practices from a decade of training by a center for public health preparedness.

PubMed

Reid, William Michael; Brown, Lisa M; Landis, Danielle C

2014-01-01

To review a decade's experience of a Centers for Disease Control and Preparedness (CDC) funded Center for Public Health Preparedness (hereafter referred to as the Center) and to identify interventions that led to surmounting serious obstacles to achieving the Center's CDC-mandated goals and objectives. The Center's purpose was to train the public health workforce to protect the population from bioterrorism, infectious diseases, and emerging public health threats. This case study used the concepts of the judgment process as developed by Noel Tichy and Warren Bennis to describe the experiences and actions of the Center's leaders. Center staff used public health principles of collaboration, the use of relevant science, and professional training principles in developing and delivering training in epidemiology, behavioral health, crisis leadership, and other fields through distance learning and on-site methods. The study's primary focus was on training in Florida, although the program's reach was national and international. Preparedness training was provided to approximately 10,000 public health officials, primarily drawn from Florida. This is a descriptive study of the Center's activities. The interventions were the steps taken by Center leadership to accomplish the federal and state goals of the program, despite meeting major challenges. The outcome measures were degrees of success, as measured by federal and state officials and other indicators, in delivering high quality training that met CDC and state goals. The Center delivered trainings in fields determined to be needed in Florida and nationally. Participant and observer evaluations were strongly positive. Nationally published papers and presentations contributed to the training evidence base. The Florida Department of Health incorporated the trainings into Florida's mandatory training for Incident Command strike teams. The leaders of the Center and the Florida Department of Health developed a formal statement of

Improved obstacle avoidance and navigation for an autonomous ground vehicle

NASA Astrophysics Data System (ADS)

Giri, Binod; Cho, Hyunsu; Williams, Benjamin C.; Tann, Hokchhay; Shakya, Bicky; Bharam, Vishal; Ahlgren, David J.

2015-01-01

This paper presents improvements made to the intelligence algorithms employed on Q, an autonomous ground vehicle, for the 2014 Intelligent Ground Vehicle Competition (IGVC). In 2012, the IGVC committee combined the formerly separate autonomous and navigation challenges into a single AUT-NAV challenge. In this new challenge, the vehicle is required to navigate through a grassy obstacle course and stay within the course boundaries (a lane of two white painted lines) that guide it toward a given GPS waypoint. Once the vehicle reaches this waypoint, it enters an open course where it is required to navigate to another GPS waypoint while avoiding obstacles. After reaching the final waypoint, the vehicle is required to traverse another obstacle course before completing the run. Q uses modular parallel software architecture in which image processing, navigation, and sensor control algorithms run concurrently. A tuned navigation algorithm allows Q to smoothly maneuver through obstacle fields. For the 2014 competition, most revisions occurred in the vision system, which detects white lines and informs the navigation component. Barrel obstacles of various colors presented a new challenge for image processing: the previous color plane extraction algorithm would not suffice. To overcome this difficulty, laser range sensor data were overlaid on visual data. Q also participates in the Joint Architecture for Unmanned Systems (JAUS) challenge at IGVC. For 2014, significant updates were implemented: the JAUS component accepted a greater variety of messages and showed better compliance to the JAUS technical standard. With these improvements, Q secured second place in the JAUS competition.

A bio-inspired kinematic controller for obstacle avoidance during reaching tasks with real robots.

PubMed

Srinivasa, Narayan; Bhattacharyya, Rajan; Sundareswara, Rashmi; Lee, Craig; Grossberg, Stephen

2012-11-01

This paper describes a redundant robot arm that is capable of learning to reach for targets in space in a self-organized fashion while avoiding obstacles. Self-generated movement commands that activate correlated visual, spatial and motor information are used to learn forward and inverse kinematic control models while moving in obstacle-free space using the Direction-to-Rotation Transform (DIRECT). Unlike prior DIRECT models, the learning process in this work was realized using an online Fuzzy ARTMAP learning algorithm. The DIRECT-based kinematic controller is fault tolerant and can handle a wide range of perturbations such as joint locking and the use of tools despite not having experienced them during learning. The DIRECT model was extended based on a novel reactive obstacle avoidance direction (DIRECT-ROAD) model to enable redundant robots to avoid obstacles in environments with simple obstacle configurations. However, certain configurations of obstacles in the environment prevented the robot from reaching the target with purely reactive obstacle avoidance. To address this complexity, a self-organized process of mental rehearsals of movements was modeled, inspired by human and animal experiments on reaching, to generate plans for movement execution using DIRECT-ROAD in complex environments. These mental rehearsals or plans are self-generated by using the Fuzzy ARTMAP algorithm to retrieve multiple solutions for reaching each target while accounting for all the obstacles in its environment. The key aspects of the proposed novel controller were illustrated first using simple examples. Experiments were then performed on real robot platforms to demonstrate successful obstacle avoidance during reaching tasks in real-world environments. Copyright © 2012 Elsevier Ltd. All rights reserved.

Perceived demands and postexercise physical dysfunction in CrossFit® compared to an ACSM based training session.

PubMed

Drum, Scott N; Bellovary, Bryanne N; Jensen, Randall L; Moore, Maggy T; Donath, Lars

2017-05-01

CrossFit® is considered an intense and extreme conditioning program (ECP) that can cause overtraining and injury. Exertional Rhabdomyolysis (ER) - breakdown of muscle tissue - after ECP has been reported in CrossFit® and might be linked to comparatively high rates of subjectively perceived exertion levels. Therefore, the present study aimed at recording symptoms of postexercise physical dysfunction (e.g., excessive muscle soreness, shortness of breath) following CrossFit® and ratings of perceived exertion (RPE) during CrossFit® compared with training according to the American College of Sports Medicine (ACSM) guidelines. A validated questionnaire was completed by 101 CrossFit® (age: 35±8 years; weight: 79±16 kg) and 56 ACSM (age: 35±10 years; weight: 75±27 kg) participants. CrossFit® and ACSM groups, respectively, reported significantly different RPE levels of 7.3±1.7 and 5.5±1.4 (P≤0.001) and amounts of hard days per week of 4.0±1.1 and 3.5±1.4 (P=0.04). The five most frequent and hardest ECP workouts of the day (WODs) were Fran (47), Murph (27), Fight Gone Bad (10), Helen (9) and Filthy 50 (9). Presence of severe post-exercise symptoms was notably higher in CrossFit® for excessive fatigue (42 vs. 8; P<0.001), muscle soreness (96 vs. 48; P=0.04), muscle swelling (19 vs. 4; P=0.048), shortness of breath (13 vs. 1; P=0.02), muscle pain to touch (31 vs. 4; P=0.001), and limited muscle movement during workout (37 vs. 9; P=0.007). CrossFit® leads to "very hard" perceived exertion causing detrimental post-exercise effects on muscle and ventilatory function in experienced athletes. Improved training progression with adequate recovery schedules are needed to prevent severe muscle injury, such as ER.

Cross-education of muscular strength following unilateral resistance training: a meta-analysis.

PubMed

Manca, A; Dragone, D; Dvir, Z; Deriu, Franca

2017-11-01

Cross-education (CE) of strength is a well-known phenomenon whereby exercise of one limb can induce strength gains in the contralateral untrained limb. The only available meta-analyses on CE, which date back to a decade ago, estimated a modest 7.8% increase in contralateral strength following unilateral training. However, in recent years new evidences have outlined larger contralateral gains, which deserve to be systematically evaluated. Therefore, the aim of this meta-analysis was to appraise current data on CE and determine its overall magnitude of effect. Five databases were searched from inception to December 2016. All randomized controlled trials focusing on unilateral resistance training were carefully checked by two reviewers who also assessed the eligibility of the identified trials and extracted data independently. The risk of bias was assessed using the Cochrane Risk-of-Bias tool. Thirty-one studies entered the meta-analysis. Data from 785 subjects were pooled and subgroup analyses by body region (upper/lower limb) and type of training (isometric/concentric/eccentric/isotonic-dynamic) were performed. The pooled estimate of CE was a significant 11.9% contralateral increase (95% CI 9.1-14.8; p < 0.00001; upper limb: + 9.4%, p < 0.00001; lower limb: + 16.4%, p < 0.00001). Significant CE effects were induced by isometric (8.2%; p = 0.0003), concentric (11.3%; p < 0.00001), eccentric (17.7%; p = 0.003) and isotonic-dynamic training (15.9%; p < 0.00001), although a high risk of bias was detected across the studies. Unilateral resistance training induces significant contraction type-dependent gains in the contralateral untrained limb. Methodological issues in the included studies are outlined to provide guidance for a reliable quantification of CE in future studies.

The influence of velocity-specific resistance training on the in vivo torque-velocity relationship and the cross-sectional area of quadriceps femoris.

PubMed

Petersen, S R; Bagnall, K M; Wenger, H A; Reid, D C; Castor, W R; Quinney, H A

1989-01-01

This work was supported by Sport Canada end Hydra-Fitness Industries. In order to investigate the effects of velocity-specific resistance training, 30 healthy, male varsity athletes were assigned to either high (HVR) or low (LVR) velocity training or control (CG) groups. Subjects completed two 20-sec sets of maximal exercise at each of six hydraulic resistance stations for the lower limb. Resistances were adjusted as necessary to maintain consistent average angular velocities of approximately 1.05 and 3.14 rad/sec for the LVR and HVR groups, respectively. Subjects trained on alternate days for 6 weeks, completing either two (weeks 1 and 2) or three (weeks 3-6) circuits of the six stations each session. Peak knee extension torques were improved (p < 0.05) for the LVR group at all of seven angular velocities tested between 1.05 and 4.19 rad/sec. Improvements (p < 0.05) were also observed for the HVR group, but only at angular velocities of 2.62, 3.14, 3.66, and 4.19 rad/sec. Cross-sectional area of the quadriceps femoris muscle group obtained from serial computer tomography (CT) scans was increased (p < 0.05) for both training groups. No significant changes in either strength or cross-sectional area were observed for control subjects. These results indicate that while both of the training programs resulted in increased cross-sectional area of the knee extensors, the observed changes in strength performance are likely due to other factors which may be mediated by the different training velocities. J Orthop Sports Phys Ther 1989;10(11):456-462.

Obstacle Detection in Indoor Environment for Visually Impaired Using Mobile Camera

NASA Astrophysics Data System (ADS)

Rahman, Samiur; Ullah, Sana; Ullah, Sehat

2018-01-01

Obstacle detection can improve the mobility as well as the safety of visually impaired people. In this paper, we present a system using mobile camera for visually impaired people. The proposed algorithm works in indoor environment and it uses a very simple technique of using few pre-stored floor images. In indoor environment all unique floor types are considered and a single image is stored for each unique floor type. These floor images are considered as reference images. The algorithm acquires an input image frame and then a region of interest is selected and is scanned for obstacle using pre-stored floor images. The algorithm compares the present frame and the next frame and compute mean square error of the two frames. If mean square error is less than a threshold value α then it means that there is no obstacle in the next frame. If mean square error is greater than α then there are two possibilities; either there is an obstacle or the floor type is changed. In order to check if the floor is changed, the algorithm computes mean square error of next frame and all stored floor types. If minimum of mean square error is less than a threshold value α then flour is changed otherwise there exist an obstacle. The proposed algorithm works in real-time and 96% accuracy has been achieved.

Cross-cultural issues in CRM training

NASA Technical Reports Server (NTRS)

Merritt, A.; Helmreich, R. L. (Principal Investigator)

1995-01-01

The author presents six stages of intercultural awareness and relates them to cockpit resource management training. A case study examines cultural differences between South American and United States flight crews and the problems that can occur when pilots minimize differences. Differences in leadership styles are highlighted and strategies for training South American pilots are provided.

76 FR 52239 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-22

... Minimums & Obstacle DP, Orig-A Red Oak, IA, Red Oak Muni, Takeoff Minimums & Obstacle DP, Amdt 3 Storm Lake, IA, Storm Lake Muni, Takeoff Minimums & Obstacle DP, Orig Dwight, IL, Dwight, Takeoff Minimums..., Florence Rgnl, RNAV (GPS) RWY 9, Orig-A Spearfish, SD, Black Hills-Clydes Ice Field, RNAV (GPS) RWY 13...

Obstacles to Scientific Research in Light of a Number of Variables

ERIC Educational Resources Information Center

Algadheeb, Nourah A.; Almeqren, Monira A.

2014-01-01

The present study aimed to identify the scientific research obstacles facing faculty members in the College of Education at Princess Nora bint Abdul Rahman University (PNU) and to determine the differences in the obstacles according to age, academic rank, scientific specialty, marital status, number of completed studies, and time since the last…

Constructing target product profiles (TPPs) to help vaccines overcome post-approval obstacles

PubMed Central

Lee, Bruce Y.; Burke, Donald S.

2012-01-01

As history has demonstrated, post-approval obstacles can impede a vaccine’s use and potentially lead to its withdrawal. Addressing these potential obstacles when changes in a vaccine’s technology can still be easily made may improve a vaccine’s chances of success. Augmented vaccine target product profiles (TPPs) can help vaccine scientists better understand and anticipate these obstacles and galvanize conversations among various vaccine stakeholders (e.g., scientists, marketers, business development managers, policy makers, public health officials, health care workers, third party payors, etc.) earlier in a vaccine’s development. PMID:19782109

Mesoscopic model for filament orientation in growing actin networks: the role of obstacle geometry

NASA Astrophysics Data System (ADS)

Weichsel, Julian; Schwarz, Ulrich S.

2013-03-01

Propulsion by growing actin networks is a universal mechanism used in many different biological systems, ranging from the sheet-like lamellipodium of crawling animal cells to the actin comet tails induced by certain bacteria and viruses in order to move within their host cells. Although the core molecular machinery for actin network growth is well preserved in all of these cases, the geometry of the propelled obstacle varies considerably. During recent years, filament orientation distribution has emerged as an important observable characterizing the structure and dynamical state of the growing network. Here we derive several continuum equations for the orientation distribution of filaments growing behind stiff obstacles of various shapes and validate the predicted steady state orientation patterns by stochastic computer simulations based on discrete filaments. We use an ordinary differential equation approach to demonstrate that for flat obstacles of finite size, two fundamentally different orientation patterns peaked at either ±35° or +70°/0°/ - 70° exhibit mutually exclusive stability, in agreement with earlier results for flat obstacles of very large lateral extension. We calculate and validate phase diagrams as a function of model parameters and show how this approach can be extended to obstacles with piecewise straight contours. For curved obstacles, we arrive at a partial differential equation in the continuum limit, which again is in good agreement with the computer simulations. In all cases, we can identify the same two fundamentally different orientation patterns, but only within an appropriate reference frame, which is adjusted to the local orientation of the obstacle contour. Our results suggest that two fundamentally different network architectures compete with each other in growing actin networks, irrespective of obstacle geometry, and clarify how simulated and electron tomography data have to be analyzed for non-flat obstacle geometries.

Effect of obstacle position in the flow of sheep through a narrow door.

PubMed

Zuriguel, Iker; Olivares, Jorge; Pastor, José M; Martín-Gómez, César; Ferrer, Luis M; Ramos, Juan J; Garcimartín, Angel

2016-09-01

In a recent work [Phys. Rev. E 91, 022808 (2015)PLEEE81539-375510.1103/PhysRevE.91.022808] it was reported that placing an obstacle in front of a gate has a beneficial effect in the flow of sheep through it. Here, we extend such results by implementing three different obstacle positions. We have observed that the flow is improved in two cases, while it worsens in the other one; the last instance happens when the obstacle is too close to the door. In this situation, the outcomes suggest that clogging develops between the doorjamb and the obstacle, contrary to the cases when the obstacle is farther, in which case clogging always occurs at the very door. The effectiveness of the obstacle (a strategy put forward to alleviate clogging in emergency exits) is therefore quite sensitive to its location. In addition, the study of the temporal evolution of the flow rate as the test develops makes evident a steady behavior during the entire duration of the entrance. This result is at odds with recent findings in human evacuation tests where the flow rate varies over time, therefore challenging the fairness of straightforward comparisons between pedestrian behavior and animal experimental observations.

Stability of gas channels in a dense suspension in the presence of obstacles

NASA Astrophysics Data System (ADS)

Poryles, Raphaël; Varas, Germán; Vidal, Valérie

2017-06-01

We investigate experimentally the influence of a fixed obstacle on gas rising in a dense suspension. Air is injected at a constant flow rate by a single nozzle at the bottom center of a Hele-Shaw cell. Without obstacles, previous works have shown that a fluidized zone is formed with a parabolic shape, with a central air channel and two granular convection rolls on its sides. Here, we quantify the influence of the obstacle's shape, size, and height on the location and dynamics of the central air channel. Different regimes are reported: the air channel can simply deviate (stable), or it can switch sides over time (unstable), leading to two signatures not only above the obstacle, but sometimes also below it. This feedback also influences the channel deviation when bypassing the obstacle. A wake of less or no motion is reported above the largest obstacles as well as the maximum probability of gas location, which can be interesting for practical applications. The existence of a critical height hc≃7 cm is discussed and compared with the existence of an air finger that develops from the injection nozzle and is stable in time. A dimensionless number describing the transition between air fingering and fracturing makes it possible to predict the channel's stability.

Comparison of cross culture engineering ethics training using the simulator for engineering ethics education.

PubMed

Chung, Christopher

2015-04-01

This paper describes the use and analysis of the Simulator for Engineering Ethics Education (SEEE) to perform cross culture engineering ethics training and analysis. Details describing the first generation and second generation development of the SEEE are published in Chung and Alfred, Science and Engineering Ethics, vol. 15, 2009 and Alfred and Chung, Science and Engineering Ethics, vol. 18, 2012. In this effort, a group of far eastern educated students operated the simulator in the instructional, training, scenario, and evaluation modes. The pre and post treatment performance of these students were compared to U.S. Educated students. Analysis of the performance indicated that the far eastern educated student increased their level of knowledge 23.7 percent while U.S. educated students increased their level of knowledge by 39.3 percent.

Cross-modal transfer of the conditioned eyeblink response during interstimulus interval discrimination training in young rats

PubMed Central

Brown, Kevin L.; Stanton, Mark E.

2008-01-01

Eyeblink classical conditioning (EBC) was observed across a broad developmental period with tasks utilizing two interstimulus intervals (ISIs). In ISI discrimination, two distinct conditioned stimuli (CSs; light and tone) are reinforced with a periocular shock unconditioned stimulus (US) at two different CS-US intervals. Temporal uncertainty is identical in design with the exception that the same CS is presented at both intervals. Developmental changes in conditioning have been reported in each task beyond ages when single-ISI learning is well developed. The present study sought to replicate and extend these previous findings by testing each task at four separate ages. Consistent with previous findings, younger rats (postnatal day – PD - 23 and 30) trained in ISI discrimination showed evidence of enhanced cross-modal influence of the short CS-US pairing upon long CS conditioning relative to older subjects. ISI discrimination training at PD43-47 yielded outcomes similar to those in adults (PD65-71). Cross-modal transfer effects in this task therefore appear to diminish between PD30 and PD43-47. Comparisons of ISI discrimination with temporal uncertainty indicated that cross-modal transfer in ISI discrimination at the youngest ages did not represent complete generalization across CSs. ISI discrimination undergoes a more protracted developmental emergence than single-cue EBC and may be a more sensitive indicator of developmental disorders involving cerebellar dysfunction. PMID:18726989

Obstacles of Teaching Mathematics Faced by the Class Teachers in Jordan

ERIC Educational Resources Information Center

Nejem, Khamis Mousa; Muhanna, Waffa

2013-01-01

The purpose of the study is to investigate the obstacles of teaching mathematics faced by the class teachers in Jordan. To achieve this purpose a study sample of 192 male and female class teachers was selected randomly from government schools. The instrument of the study was a questionnaire used to investigate the obstacles of mathematics…

Training for Agriculture and Rural Development--1976. FAO Economic and Social Development Series No. 2.

ERIC Educational Resources Information Center

United Nations Food and Agriculture Organization, Rome (Italy).

Focus of this 1976 journal on agricultural and rural development education is how to deal with the shortage of trained manpower which is an obstacle to large-scale rural development efforts. The journal's theme is that a broader approach must be made to generate adequate numbers of trained manpower--all types of nonformal education (agricultural…

Obstacle stepping involves spinal anticipatory activity associated with quadrupedal limb coordination.

PubMed

Michel, J; van Hedel, H J A; Dietz, V

2008-04-01

Obstacle avoidance steps are associated with a facilitation of spinal reflexes in leg muscles. Here we have examined the involvement of both leg and arm muscles. Subjects walking with reduced vision on a treadmill were acoustically informed about an approaching obstacle and received feedback about task performance. Reflex responses evoked by tibial nerve stimulation were observed in all arm and leg muscles examined in this study. They were enhanced before the execution of obstacle avoidance compared with normal steps and showed an exponential adaptation in contralateral arm flexor muscles corresponding to the improvement of task performance. This enhancement was absent when the body was partially supported during the task. During the execution of obstacle steps, electromyographic activity in the arm muscles mimicked the preceding reflex behaviour with respect to enhancement and adaptation. Our results demonstrate an anticipatory quadrupedal limb coordination with an involvement of proximal arm muscles in the acquisition and performance of this precision locomotor task. This is presumably achieved by an up-regulated activity of coupled cervico-thoracal interneuronal circuits.

Training Characteristics During Pregnancy and Postpartum in the World’s Most Successful Cross Country Skier

PubMed Central

Solli, Guro S.; Sandbakk, Øyvind

2018-01-01

This case-study investigated the training characteristics, physiological capacity, and body composition of the world’s most successful cross country skier during the 40-week pregnancy, and the 61-week postpartum. Training data was systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and mode (running, cycling, and skiing/roller skiing). The training volume [mean ± standard deviation (median)] during pregnancy was 12.9 ± 7.3(10.0) h/week in the first- (weeks 1–12), 18.3 ± 2.9(18.0) h/week in the second- (weeks 13–28), and 8.8 ± 4.4(9.6) h/week in the third trimester (weeks 29–40). Endurance training time was distributed into 10.9 ± 6.2(9.9), 15.2 ± 2.3(15.6), and 7.6 ± 3.8(7.9) LIT and 0.4 ± 0.5(0.0), 1.3 ± 0.4(1.4), and 0.7 ± 0.6(0.8) h/week MIT during the three trimesters. Only 2.2 h of HIT was performed during the entire pregnancy. During the first two trimesters, the distribution of exercise modes were approximately the same as pre-pregnancy, but the amount of running was reduced during the third trimester. Training volume during the postpartum periods 1–4 was 6.6 ± 3.8(7.1) (PP1; weeks 1–6), 14.1 ± 3.4(14.3) (PP2; weeks 7–12), 10.6 ± 3.8(10.4) (PP3; weeks 13–18), and 13.6 ± 4.1(14.5) h/week (PP4; weeks 19–24), respectively. Training during PP3 and PP4 was interfered with two fractions in the sacrum, leading to decreased amount of running and MIT/HIT, compensated by increased amounts of cycling. Thereafter, training volume progressively approached the pre-pregnancy values, being 18.0 ± 3.9(18.7) h/week during the general preparation- (weeks 25–44), 17.6 ± 4.4(17.3) h/week during the specific preparation- (weeks 45–53), and 16.9 ± 3.5(17.2) h/week during the competition period (CP; weeks 54–61) leading up to the subsequent world championship. The oxygen uptake at the estimated lactate threshold (LT) decreased to 90% of pre-pregnancy values

Flow through a very porous obstacle in a shallow channel.

PubMed

Creed, M J; Draper, S; Nishino, T; Borthwick, A G L

2017-04-01

A theoretical model, informed by numerical simulations based on the shallow water equations, is developed to predict the flow passing through and around a uniform porous obstacle in a shallow channel, where background friction is important. This problem is relevant to a number of practical situations, including flow through aquatic vegetation, the performance of arrays of turbines in tidal channels and hydrodynamic forces on offshore structures. To demonstrate this relevance, the theoretical model is used to (i) reinterpret core flow velocities in existing laboratory-based data for an array of emergent cylinders in shallow water emulating aquatic vegetation and (ii) reassess the optimum arrangement of tidal turbines to generate power in a tidal channel. Comparison with laboratory-based data indicates a maximum obstacle resistance (or minimum porosity) for which the present theoretical model is valid. When the obstacle resistance is above this threshold the shallow water equations do not provide an adequate representation of the flow, and the theoretical model over-predicts the core flow passing through the obstacle. The second application of the model confirms that natural bed resistance increases the power extraction potential for a partial tidal fence in a shallow channel and alters the optimum arrangement of turbines within the fence.

Overcoming an obstacle in expanding a UMLS semantic type extent.

PubMed

Chen, Yan; Gu, Huanying; Perl, Yehoshua; Geller, James

2012-02-01

This paper strives to overcome a major problem encountered by a previous expansion methodology for discovering concepts highly likely to be missing a specific semantic type assignment in the UMLS. This methodology is the basis for an algorithm that presents the discovered concepts to a human auditor for review and possible correction. We analyzed the problem of the previous expansion methodology and discovered that it was due to an obstacle constituted by one or more concepts assigned the UMLS Semantic Network semantic type Classification. A new methodology was designed that bypasses such an obstacle without a combinatorial explosion in the number of concepts presented to the human auditor for review. The new expansion methodology with obstacle avoidance was tested with the semantic type Experimental Model of Disease and found over 500 concepts missed by the previous methodology that are in need of this semantic type assignment. Furthermore, other semantic types suffering from the same major problem were discovered, indicating that the methodology is of more general applicability. The algorithmic discovery of concepts that are likely missing a semantic type assignment is possible even in the face of obstacles, without an explosion in the number of processed concepts. Copyright © 2011 Elsevier Inc. All rights reserved.

Flow through a very porous obstacle in a shallow channel

PubMed Central

Draper, S.; Nishino, T.; Borthwick, A. G. L.

2017-01-01

A theoretical model, informed by numerical simulations based on the shallow water equations, is developed to predict the flow passing through and around a uniform porous obstacle in a shallow channel, where background friction is important. This problem is relevant to a number of practical situations, including flow through aquatic vegetation, the performance of arrays of turbines in tidal channels and hydrodynamic forces on offshore structures. To demonstrate this relevance, the theoretical model is used to (i) reinterpret core flow velocities in existing laboratory-based data for an array of emergent cylinders in shallow water emulating aquatic vegetation and (ii) reassess the optimum arrangement of tidal turbines to generate power in a tidal channel. Comparison with laboratory-based data indicates a maximum obstacle resistance (or minimum porosity) for which the present theoretical model is valid. When the obstacle resistance is above this threshold the shallow water equations do not provide an adequate representation of the flow, and the theoretical model over-predicts the core flow passing through the obstacle. The second application of the model confirms that natural bed resistance increases the power extraction potential for a partial tidal fence in a shallow channel and alters the optimum arrangement of turbines within the fence. PMID:28484321

Sex and age-level differences of walking time in preschool children on an obstacle frame

PubMed Central

2012-01-01

Background Stepping over an obstacle is a kind of compound movement that makes walking more difficult, especially for preschool children. This study examines sex and age-level differences in walking time in preschool children on an obstacle frame. Methods The participants included 324 healthy preschool children: four-year-old boys (51) and girls (51), five-year-old boys (50) and girls (60), and six-year-old boys (62) and girls (50). A 5 cm- or 10 cm-high obstacle (depth 11.5 cm, width 23.5 cm) was set at the halfway point of a 200 cm × 10 cm walking course. Results The participants walked to the end of the course and back as fast as possible under three conditions: no obstacle, low obstacle and high obstacle. Walking time showed age-level differences in all conditions, but there were no differences in sex. Age levels were divided into two groups, with one group within the first six months of their birthday, and the second group within the last six months of that year. Walking time for children in the first half of their fourth year was longer than that of the five- and six-year-old children. In addition, for children in the last half of their fourth year, walking time was longer than both sexes in the last half of their fifth and sixth years. The children in the latter half of their fifth year had a longer walking time in the high obstacle condition than those in the last half of their sixth year. In the four-year-old participants, walking time was shorter with no obstacles than with a high obstacle frame. Conclusions In the above data, obstacle course walking time does not show a gender difference, except that the four-year-old participants needed longer than the five- and six-year-old children. Setting the obstacle 10 cm high also produced a different walking time in the five- and six-year-old participants. The high obstacle step test (10 cm) best evaluated the dynamic balance of preschool children. PMID:22738328

Supersonic flows past an obstacle in Yukawa liquids

NASA Astrophysics Data System (ADS)

Charan, Harish; Ganesh, Rajaraman

2018-04-01

Shock formation, when a supersonic flow passes a stationary obstacle, is ubiquitous in nature. Considering particles mediating via a Yukawa-type interaction as a prototype for a strongly coupled complex plasma, characterized by coupling strength (Γ, ratio of the average potential to kinetic energy per particle) and screening parameter (κ, ratio of the mean inter-particle distance to the shielding length), we address the fundamental problem of supersonic fluid flow U0, past a stationary obstacle immersed in this strongly coupled system. We here report the results on the bow shocks formed in Yukawa liquids when the liquid flows at speeds larger than the speed of sound in the system. Depending on the values of Mach number MC L=U/0 CL , where CL is the longitudinal speed of sound in the system, the bow shocks are found to be either traveling or localized. We find that for the transonic flows (0.8 ≲ MC L≲ 1.2), the bow shocks travel in the upstream direction opposite to the incoming fluid. The phase velocity of the traveling bow shocks is found to be a non-monotonous function of κ, varying as ∝1 /k1.11 at a fixed value of Γ, and is found to be independent of Γ at a fixed value of κ. It is observed that for the flow values with MC L>1.5 , the shock waves do not travel in the upstream direction but instead form a stationary arc like structure around the obstacle. For the fluid flows with 1 ≲ MC L≲ 2.6 , secondary bow shocks are seen to emerge behind the stationary obstacle which travel in the downstream direction, and the phase velocity of these secondary bow shocks is found to be equal to that of the primary bow shocks.

Development and validation of the short version of the diabetes obstacles questionnaire (DOQ-30) in six European countries.

PubMed

Pilv, Liina; Vermeire, Etienne; Rätsep, Anneli; Moreau, Alain; Nikolić, Dragica; Petek, Davorina; Yaman, Hakan; Oona, Marje; Kalda, Ruth

2016-01-01

Patients with type 2 diabetes reveal different obstacles in living with the disease. The EGPRN initiated a qualitative research EUROBSTACLE to create a broadly conceptualized diabetes-related quality of life (DR-QoL) instrument. It led to the development of the diabetes obstacle questionnaire (DOQ), a five-point Likert-scaled measure, consisting of 78 items in eight scales. To develop and validate a short, easy-to-use version of the DOQ. A cross-sectional study with the DOQ was carried out. Participants answered the DOQ and GPs added some clinical data from their medical records. Data of 853 patients from Belgium, France, Estonia, Serbia, Slovenia, and Turkey were included in the analysis. The selection of items for the short version of the DOQ was achieved with exploratory factor analysis (EFA). Construct validity was proved with EFA and Pearson correlations between the DOQ and the new DOQ-30. Internal reliability was established with Cronbach's alpha. DOQ-30 resulted in 30 items in nine subscales. It explained 49.8% of items' variance. It shows a considerable good internal reliability and construct validity. The DOQ-30 is a five-point Likert-scaled broadly conceptualized measure of DR-QoL. It addresses a variety of obstacles, such as social, psychological, cognitive and behavioural. The DOQ-30 is ready for implementation in general practice and research in Europe as a valuable instrument to assess DR-QoL.

Effects of driver attention on rail crossing safety and : The effects of auditory warnings and driver distraction on rail crossing safety.

DOT National Transportation Integrated Search

2016-05-05

Train-vehicle/train collisions at highway-rail grade crossings (crossings) continue to be a major issue in the US and around the world. Although the United States has made great strides in improving safety at crossings since the 1970s, vehicle-train ...

On Stationary Navier-Stokes Flows Around a Rotating Obstacle in Two-Dimensions

NASA Astrophysics Data System (ADS)

Higaki, Mitsuo; Maekawa, Yasunori; Nakahara, Yuu

2018-05-01

We study the two-dimensional stationary Navier-Stokes equations describing the flows around a rotating obstacle. The unique existence of solutions and their asymptotic behavior at spatial infinity are established when the rotation speed of the obstacle and the given exterior force are sufficiently small.

Vortex shedding from obstacles: theoretical frequency prediction

NASA Astrophysics Data System (ADS)

Pier, Benoît

2001-11-01

The existence of self-sustained oscillations in spatially developing systems is closely related to the presence of a locally absolutely unstable region. A recent investigation of a ``synthetic wake'' (a wake with no solid obstacle and no reverse flow region) has proved [Pier and Huerre, J. Fluid Mech. 435, 145 (2001)] that the observed Kármán vortex street is a nonlinear elephant global mode. The same criterion is now shown to hold for real obstacles. Local properties are derived from the unperturbed basic flow computed by enforcing a symmetry condition on the central line. Application of the theoretical criterion then yields the expected Strouhal vortex shedding frequency. The thus predicted frequency is in excellent agreement with direct numerical simulations of the complete flow. The use of the frequency selection mechanism to control the vortex shedding will also be discussed.

Dark soliton past a finite-size obstacle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilas, Nicolas; Pavloff, Nicolas

2005-09-15

We consider the collision of a dark soliton with an obstacle in a quasi-one-dimensional Bose condensate. We show that in many respects the soliton behaves as an effective classical particle of mass twice the mass of a bare particle, evolving in an effective potential which is a convolution of the actual potential describing the obstacle. Radiative effects beyond this approximation are also taken into account. The emitted waves are shown to form two counterpropagating wave packets, both moving at the speed of sound. We determine, at leading order, the total amount of radiation emitted during the collision and compute themore » acceleration of the soliton due to the collisional process. It is found that the radiative process is quenched when the velocity of the soliton reaches the velocity of sound in the system.« less

Cross-training in birds: cold and exercise training produce similar changes in maximal metabolic output, muscle masses and myostatin expression in house sparrows (Passer domesticus).

PubMed

Zhang, Yufeng; Eyster, Kathleen; Liu, Jin-Song; Swanson, David L

2015-07-01

Maximal metabolic outputs for exercise and thermogenesis in birds presumably influence fitness through effects on flight and shivering performance. Because both summit (Msum, maximum thermoregulatory metabolic rate) and maximum (MMR, maximum exercise metabolic rate) metabolic rates are functions of skeletal muscle activity, correlations between these measurements and their mechanistic underpinnings might occur. To examine whether such correlations occur, we measured the effects of experimental cold and exercise training protocols for 3 weeks on body (Mb) and muscle (Mpec) masses, basal metabolic rate (BMR), Msum, MMR, pectoralis mRNA and protein expression for myostatin, and mRNA expression of TLL-1 and TLL-2 (metalloproteinase activators of myostatin) in house sparrows (Passer domesticus). Both training protocols increased Msum, MMR, Mb and Mpec, but BMR increased with cold training and decreased with exercise training. No significant differences occurred for pectoralis myostatin mRNA expression, but cold and exercise increased the expression of TLL-1 and TLL-2. Pectoralis myostatin protein levels were generally reduced for both training groups. These data clearly demonstrate cross-training effects of cold and exercise in birds, and are consistent with a role for myostatin in increasing pectoralis muscle mass and driving organismal increases in metabolic capacities. © 2015. Published by The Company of Biologists Ltd.

Cross-training in birds: cold and exercise training produce similar changes in maximal metabolic output, muscle masses and myostatin expression in house sparrows (Passer domesticus)

PubMed Central

Zhang, Yufeng; Eyster, Kathleen; Liu, Jin-Song; Swanson, David L.

2015-01-01

ABSTRACT Maximal metabolic outputs for exercise and thermogenesis in birds presumably influence fitness through effects on flight and shivering performance. Because both summit (Msum, maximum thermoregulatory metabolic rate) and maximum (MMR, maximum exercise metabolic rate) metabolic rates are functions of skeletal muscle activity, correlations between these measurements and their mechanistic underpinnings might occur. To examine whether such correlations occur, we measured the effects of experimental cold and exercise training protocols for 3 weeks on body (Mb) and muscle (Mpec) masses, basal metabolic rate (BMR), Msum, MMR, pectoralis mRNA and protein expression for myostatin, and mRNA expression of TLL-1 and TLL-2 (metalloproteinase activators of myostatin) in house sparrows (Passer domesticus). Both training protocols increased Msum, MMR, Mb and Mpec, but BMR increased with cold training and decreased with exercise training. No significant differences occurred for pectoralis myostatin mRNA expression, but cold and exercise increased the expression of TLL-1 and TLL-2. Pectoralis myostatin protein levels were generally reduced for both training groups. These data clearly demonstrate cross-training effects of cold and exercise in birds, and are consistent with a role for myostatin in increasing pectoralis muscle mass and driving organismal increases in metabolic capacities. PMID:25987736

An Obstacle-Tolerant Path Planning Algorithm for Mobile-Anchor-Node-Assisted Localization

PubMed Central

Tsai, Rong-Guei

2018-01-01

The location information obtained using a sensor is a critical requirement in wireless sensor networks. Numerous localization schemes have been proposed, among which mobile-anchor-node-assisted localization (MANAL) can reduce costs and overcome environmental constraints. A mobile anchor node (MAN) provides its own location information to assist the localization of sensor nodes. Numerous path planning schemes have been proposed for MANAL, but most scenarios assume the absence of obstacles in the environment. However, in a realistic environment, sensor nodes cannot be located because the obstacles block the path traversed by the MAN, thereby rendering the sensor incapable of receiving sufficient three location information from the MAN. This study proposes the obstacle-tolerant path planning (OTPP) approach to solve the sensor location problem owing to obstacle blockage. OTPP can approximate the optimum beacon point number and path planning, thereby ensuring that all the unknown nodes can receive the three location information from the MAN and reduce the number of MAN broadcast packet times. Experimental results demonstrate that OTPP performs better than Z-curves because it reduces the total number of beacon points utilized and is thus more suitable in an obstacle-present environment. Compared to the Z-curve, OTPP can reduce localization error and improve localization coverage. PMID:29547582

The Effects of Shoe Traction and Obstacle Height on Lower Extremity Coordination Dynamics during Walking

PubMed Central

Decker, Leslie; Houser, Jeremy J.; Noble, John M.; Karst, Gregory M.; Stergiou, Nicholas

2009-01-01

This study aims to investigate the effects of shoe traction and obstacle height on lower extremity relative phase dynamics (analysis of intralimb coordination) during walking to better understand the mechanisms employed to avoid slippage following obstacle clearance. Ten participants walked at a self-selected pace during eight conditions: four obstacle heights (0%, 10%, 20%, and 40% of limb length) while wearing two pairs of shoes (low and high traction). A coordination analysis was used and phasing relationships between lower extremity segments were examined. The results demonstrated that significant behavioral changes were elicited under varied obstacle heights and frictional conditions. Both decreasing shoe traction and increasing obstacle height resulted in a more in-phase relationship between the interacting lower limb segments. The higher the obstacle and the lower the shoe traction, the more unstable the system became. These changes in phasing relationship and variability are indicators of alterations in coordinative behavior, which if pushed further may have lead to falling. PMID:19187929

Training health care professionals in root cause analysis: a cross-sectional study of post-training experiences, benefits and attitudes.

PubMed

Bowie, Paul; Skinner, Joe; de Wet, Carl

2013-02-07

Root cause analysis (RCA) originated in the manufacturing engineering sector but has been adapted for routine use in healthcare to investigate patient safety incidents and facilitate organizational learning. Despite the limitations of the RCA evidence base, healthcare authorities and decision makers in NHS Scotland - similar to those internationally - have invested heavily in developing training programmes to build local capacity and capability, and this is a cornerstone of many organizational policies for investigating safety-critical issues. However, to our knowledge there has been no systematic attempt to follow-up and evaluate post-training experiences of RCA-trained staff in Scotland. Given the significant investment in people, time and funding we aimed to capture and learn from the reported experiences, benefits and attitudes of RCA-trained staff and the perceived impact on healthcare systems and safety. We adapted a questionnaire used in a published Australian research study to undertake a cross sectional online survey of health care professionals (e.g. nursing & midwifery, medical doctors and pharmacists) formally trained in RCA by a single territorial health board region in NHS Scotland. A total of 228/469 of invited staff completed the survey (48%). A majority of respondents had yet to participate in a post-training RCA investigation (n=127, 55.7%). Of RCA-experience staff, 71 had assumed a lead investigator role (70.3%) on one or more occasions. A clear majority indicated that their improvement recommendations were generally or partly implemented (82%). The top three barriers to RCA success were cited as: lack of time (54.6%), unwilling colleagues (34%) and inter-professional differences (31%). Differences in agreement levels between RCA-experienced and inexperienced respondents were noted on whether a follow-up session would be beneficial after conducting RCA (65.3% v 39.4%) and if peer feedback on RCA reports would be of educational value (83.2% v 37

Identification of Vibrotactile Patterns Encoding Obstacle Distance Information.

PubMed

Kim, Yeongmi; Harders, Matthias; Gassert, Roger

2015-01-01

Delivering distance information of nearby obstacles from sensors embedded in a white cane-in addition to the intrinsic mechanical feedback from the cane-can aid the visually impaired in ambulating independently. Haptics is a common modality for conveying such information to cane users, typically in the form of vibrotactile signals. In this context, we investigated the effect of tactile rendering methods, tactile feedback configurations and directions of tactile flow on the identification of obstacle distance. Three tactile rendering methods with temporal variation only, spatio-temporal variation and spatial/temporal/intensity variation were investigated for two vibration feedback configurations. Results showed a significant interaction between tactile rendering method and feedback configuration. Spatio-temporal variation generally resulted in high correct identification rates for both feedback configurations. In the case of the four-finger vibration, tactile rendering with spatial/temporal/intensity variation also resulted in high distance identification rate. Further, participants expressed their preference for the four-finger vibration over the single-finger vibration in a survey. Both preferred rendering methods with spatio-temporal variation and spatial/temporal/intensity variation for the four-finger vibration could convey obstacle distance information with low workload. Overall, the presented findings provide valuable insights and guidance for the design of haptic displays for electronic travel aids for the visually impaired.

Preliminary Analysis of a Randomized Trial of Computer Attention Training in Children with Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Steiner, N.; Sidhu, T. K.; Frenette, E. C.; Mitchell, K.; Perrin, E. C.

2011-01-01

Clinically significant attention problems among children present a significant obstacle to increasing student achievement. Computer-based attention training holds great promise as a way for schools to address this problem. The aim of this project is to evaluate the efficacy of two computer-based attention training systems in schools. One program…

Insecurity in the DRC: The Obstacle to Peace and Stability

DTIC Science & Technology

2016-12-01

neighboring nations since the mid-1990s. In particular, the protected presence of armed groups has been a major obstacle to peace. Based on the best...study of the DRC to analyze four DDR programs initiated in the DRC from 2002 to 2009, with the goal of better understanding why they failed. The...beginning in the mid-1990s. In particular, the protected presence of armed groups has been a major obstacle to peace. Based on the best practices

Obstacles in Qualitative Research: Possible Solutions

ERIC Educational Resources Information Center

Poggenpoel, M.; Myburgh, C. P. H.

2005-01-01

In conducting research, the identified problem in the field will determine the research strategies chosen to address the problem. When a qualitative research strategy is deemed as the most appropriate strategy to get answers to research questions, the researcher should be aware of obstacles that can be encountered in the research process. If the…

Postdeployment military mental health training: cross-national evaluations.

PubMed

Foran, Heather M; Garber, Bryan G; Zamorski, Mark A; Wray, Mariane; Mulligan, Kathleen; Greenberg, Neil; Castro, Carl Andrew; Adler, Amy B

2013-05-01

Deployments increase risk for adjustment problems in service members. To mitigate this increased risk, mental health training programs have been developed and implemented in several nations. As part of a coordinated effort, three nations adapted a U.S. mental health training program that had been validated by a series of group randomized trials demonstrating improvement in postdeployment adjustment. Implementation of evidence-based programs in a new context is challenging: How much of the original program needs to remain intact in order to retain its utility? User satisfaction rates can provide essential data to assess how well a program is accepted. This article summarizes service member ratings of postdeployment mental health training and compares ratings from service members across four nations. The participating nations (Canada, New Zealand, United Kingdom, and the United States) administered mental health training to active duty military personnel in their respective nations. Following the training, military personnel completed an evaluation of the training. Overall, across the four nations, more than 70% of military personnel agreed or strongly agreed that they were satisfied with the mental health training. Although some differences in evaluations were observed across nations, components of training that were most important to overall satisfaction with the training were strikingly similar across nations. Fundamentally, it appears feasible that despite cultural and organizational differences, a mental health training program developed in one nation can be successfully adapted for use in other nations. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Water in the presence of inert Lennard-Jones obstacles

NASA Astrophysics Data System (ADS)

Kurtjak, Mario; Urbic, Tomaz

2014-04-01

Water confined by the presence of a 'sea' of inert obstacles was examined. In the article, freely mobile two-dimensional Mercedes-Benz (MB) water put to a disordered, but fixed, matrix of Lennard-Jones disks was studied by the Monte Carlo computer simulations. For the MB water molecules in the matrix of Lennard-Jones disks, we explored the structures, hydrogen-bond-network formation and thermodynamics as a function of temperature and size and density of matrix particles. We found that the structure of model water is perturbed by the presence of the obstacles. Density of confined water, which was in equilibrium with the bulk water, was smaller than the density of the bulk water and the temperature dependence of the density of absorbed water did not show the density anomaly in the studied temperature range. The behaviour observed as a consequence of confinement is similar to that of increasing temperature, which can for a matrix lead to a process similar to capillary evaporation. At the same occupancy of space, smaller matrix molecules cause higher destruction effect on the absorbed water molecules than the bigger ones. We have also tested the hypothesis that at low matrix densities the obstacles induce an increased ordering and 'hydrogen bonding' of the MB model molecules, relative to pure fluid, while at high densities the obstacles reduce MB water structuring, as they prevent the fluid to form good 'hydrogen-bonding' networks. However, for the size of matrix molecules similar to that of water, we did not observe this effect.

Stereo and photometric image sequence interpretation for detecting negative obstacles using active gaze control and performing an autonomous jink

NASA Astrophysics Data System (ADS)

Hofmann, Ulrich; Siedersberger, Karl-Heinz

2003-09-01

Driving cross-country, the detection and state estimation relative to negative obstacles like ditches and creeks is mandatory for safe operation. Very often, ditches can be detected both by different photometric properties (soil vs. vegetation) and by range (disparity) discontinuities. Therefore, algorithms should make use of both the photometric and geometric properties to reliably detect obstacles. This has been achieved in UBM's EMS-Vision System (Expectation-based, Multifocal, Saccadic) for autonomous vehicles. The perception system uses Sarnoff's image processing hardware for real-time stereo vision. This sensor provides both gray value and disparity information for each pixel at high resolution and framerates. In order to perform an autonomous jink, the boundaries of an obstacle have to be measured accurately for calculating a safe driving trajectory. Especially, ditches are often very extended, so due to the restricted field of vision of the cameras, active gaze control is necessary to explore the boundaries of an obstacle. For successful measurements of image features the system has to satisfy conditions defined by the perception expert. It has to deal with the time constraints of the active camera platform while performing saccades and to keep the geometric conditions defined by the locomotion expert for performing a jink. Therefore, the experts have to cooperate. This cooperation is controlled by a central decision unit (CD), which has knowledge about the mission and the capabilities available in the system and of their limitations. The central decision unit reacts dependent on the result of situation assessment by starting, parameterizing or stopping actions (instances of capabilities). The approach has been tested with the 5-ton van VaMoRs. Experimental results will be shown for driving in a typical off-road scenario.

Obstacles to TQM success in health care systems.

PubMed

Mosadeghrad, Ali Mohammad

2013-01-01

Many healthcare organisations have found it difficult to implement total quality management (TQM) successfully. The aim of this paper is to explore the barriers to TQM successful implementation in the healthcare sector. This paper reports a literature review exploring the major reasons for the failure of TQM programmes in healthcare organisations. TQM implementation and its impact depend heavily on the ability of managers to adopt and adapt its values and concepts in professional healthcare organisations. Unsuccessful TQM efforts in healthcare organisations can be attributed to the strongly departmentalised, bureaucratic and hierarchical structure, professional autonomy, tensions between managers and professionals and the difficulties involved in evaluating healthcare processes and outcomes. Other obstacles to TQM success include lack of consistent managers' and employees' commitment to and involvement in TQM implementation, poor leadership and management, lack of a quality-oriented culture, insufficient training, and inadequate resources. The review was limited to empirical articles written in the English language during the past 30 years (1980-2010). The findings of this article provide policy makers and managers with a practical understanding of the factors that are likely to obstruct TQM implementation in the healthcare sector. Understanding the factors that obstruct TQM implementation would enable managers to develop more effective strategies for implementing TQM successfully in healthcare organisations.

Crossing at the Speed of Change

DTIC Science & Technology

2016-06-10

prowess. They built complicated structures and durable roads, much of which exists still today. A military force unparalleled in their time, the Romans... structures displaying their expertise and capability to could cross any obstacle at will was equally important. This was exemplified by the first recorded...constructing a bridge out of timber , complete with protective works upstream.5 Details of the bridge were found in Caesar’s personal record of his

Vision-based obstacle recognition system for automated lawn mower robot development

NASA Astrophysics Data System (ADS)

Mohd Zin, Zalhan; Ibrahim, Ratnawati

2011-06-01

Digital image processing techniques (DIP) have been widely used in various types of application recently. Classification and recognition of a specific object using vision system require some challenging tasks in the field of image processing and artificial intelligence. The ability and efficiency of vision system to capture and process the images is very important for any intelligent system such as autonomous robot. This paper gives attention to the development of a vision system that could contribute to the development of an automated vision based lawn mower robot. The works involve on the implementation of DIP techniques to detect and recognize three different types of obstacles that usually exist on a football field. The focus was given on the study on different types and sizes of obstacles, the development of vision based obstacle recognition system and the evaluation of the system's performance. Image processing techniques such as image filtering, segmentation, enhancement and edge detection have been applied in the system. The results have shown that the developed system is able to detect and recognize various types of obstacles on a football field with recognition rate of more 80%.

Vortex propagation around a wall-mounted obstacle in pulsatile flow

NASA Astrophysics Data System (ADS)

Carr, Ian A.; Plesniak, Michael W.

2015-11-01

Wall-mounted obstacles are prevalent in nature and engineering applications. Physiological flows observed in human vocal fold pathologies, such as polyps, can be modeled by flow over a wall-mounted protuberance. Despite their prevalence, studies of wall-mounted obstacles have been restricted to steady (constant velocity) freestream flow. In biological and geophysical applications, pulsatile flow is much more common, yet effects of pulsatility on the wake of a wall-mounted obstacle remain to be extensively studied. This study aims to characterize the complex physics produced in this unsteady, separated flow. Experiments were performed in a low-speed wind tunnel with a set of rotating vanes, which produce the pulsatile inflow waveform. Instantaneous and phase-averaged particle image velocimetry (PIV) results acquired around a hemispherical obstacle are presented and compared. A mechanism based on self-induced vortex propagation, analogous to that in vortex rings, is proposed to explain the observed dynamics of coherent structures. Predictions of the propagation velocity based on analytical expressions for vortex rings in a viscous fluid are compared to the experimentally measured propagation velocity. Effects of the unsteady boundary layer on the observed physics are explored. This material is based in part upon work supported by the National Science Foundation under Grant Number CBET-1236351, and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

Measures for simulator evaluation of a helicopter obstacle avoidance system

NASA Technical Reports Server (NTRS)

Demaio, Joe; Sharkey, Thomas J.; Kennedy, David; Hughes, Micheal; Meade, Perry

1993-01-01

The U.S. Army Aeroflightdynamics Directorate (AFDD) has developed a high-fidelity, full-mission simulation facility for the demonstration and evaluation of advanced helicopter mission equipment. The Crew Station Research and Development Facility (CSRDF) provides the capability to conduct one- or two-crew full-mission simulations in a state-of-the-art helicopter simulator. The CSRDF provides a realistic, full field-of-regard visual environment with simulation of state-of-the-art weapons, sensors, and flight control systems. We are using the CSRDF to evaluate the ability of an obstacle avoidance system (OASYS) to support low altitude flight in cluttered terrain using night vision goggles (NVG). The OASYS uses a laser radar to locate obstacles to safe flight in the aircraft's flight path. A major concern is the detection of wires, which can be difficult to see with NVG, but other obstacles--such as trees, poles or the ground--are also a concern. The OASYS symbology is presented to the pilot on a head-up display mounted on the NVG (NVG-HUD). The NVG-HUD presents head-stabilized symbology to the pilot while allowing him to view the image intensified, out-the-window scene through the HUD. Since interference with viewing through the display is a major concern, OASYS symbology must be designed to present usable obstacle clearance information with a minimum of clutter.

Neural correlates of obstacle negotiation in older adults: An fNIRS study.

PubMed

Chen, Michelle; Pillemer, Sarah; England, Sarah; Izzetoglu, Meltem; Mahoney, Jeannette R; Holtzer, Roee

2017-10-01

Older adults are less efficient at avoiding obstacles compared to young adults, especially under attention-demanding conditions. Using functional near-infrared-spectroscopy (fNIRS), recent studies implicated the prefrontal cortex (PFC) in cognitive control of locomotion, notably under dual-task walking conditions. The neural substrates underlying Obstacle Negotiation (ON), however, have not been established. The current study determined the role of the PFC in ON during walking in seniors. Non-demented older adults (n=90; mean age=78.1±5.5years; %female=51) underwent fNIRS acquisition to assess changes in hemodynamic activity in the PFC during normal-walk [NW] and walk-while-talk [WWT] conditions with and without obstacles. Obstacles were presented as red elliptical shapes using advanced laser technology, which resemble potholes. Linear mixed effects models were used to determine differences in oxygenated hemoglobin (HbO 2 ) levels among the four task conditions. The presence of slow gait, a risk factor for dementia and falls, served as a predictor hypothesized to moderate the effect of obstacles on PFC HbO 2 levels. PFC HbO 2 levels were significantly higher in WWT compared to NW (p<0.001) irrespective of ON. Slow gait moderated the effect of obstacles on HbO 2 levels across task conditions. Specifically, compared to participants with normal gait, PFC HbO 2 levels were significantly increased in ON-NW relative to NW (p=0.017) and ON-WWT relative to WWT (p<0.001) among individuals with slow gait. Consistent with Compensatory Reallocation, ON required greater PFC involvement among individuals with mobility limitations. Copyright © 2017 Elsevier B.V. All rights reserved.

Statistical properties of gravity-driven granular discharge flow under the influence of an obstacle

NASA Astrophysics Data System (ADS)

Endo, Keita; Katsuragi, Hiroaki

2017-06-01

Two-dimensional granular discharge flow driven by gravity under the influence of an obstacle is experimentally investigated. A horizontal exit of width W is opened at the bottom of vertical Hele-Shaw cell filled with stainless-steel particles to start the discharge flow. In this experiment, a circular obstacle is placed in front of the exit. Thus, the distance between the exit and obstacle L is also an important parameter. During the discharge, granular-flow state is acquired by a high-speed camera. The bulk discharge-flow rate is also measured by load cell sensors. The obtained high-speed-image data are analyzed to clarify the particle-level granular-flow dynamics. Using the measured data, we find that the obstacle above the exit affects the granular- flow field. Specifically, the existence of obstacle results in large horizontal granular temperature and small packing fraction. This tendency becomes significant when L is smaller than approximately 6Dg when W ≃ 4Dg, where Dg is diameter of particles.

Short range laser obstacle detector. [for surface vehicles using laser diode array

NASA Technical Reports Server (NTRS)

Kuriger, W. L. (Inventor)

1973-01-01

A short range obstacle detector for surface vehicles is described which utilizes an array of laser diodes. The diodes operate one at a time, with one diode for each adjacent azimuth sector. A vibrating mirror a short distance above the surface provides continuous scanning in elevation for all azimuth sectors. A diode laser is synchronized with the vibrating mirror to enable one diode laser to be fired, by pulses from a clock pulse source, a number of times during each elevation scan cycle. The time for a given pulse of light to be reflected from an obstacle and received is detected as a measure of range to the obstacle.

Collaborative Learning Practices: Teacher and Student Perceived Obstacles to Effective Student Collaboration

ERIC Educational Resources Information Center

Le, Ha; Janssen, Jeroen; Wubbels, Theo

2018-01-01

While the educational literature mentions several obstacles affecting the effectiveness of collaborative learning (CL), they have often been investigated through the perceptions of only one actor, either teachers or students. Therefore, some sources of obstacles that teachers and students encounter may not have been revealed. In this study, 19…

Obstacle Detection and Avoidance System Based on Monocular Camera and Size Expansion Algorithm for UAVs

PubMed Central

Al-Kaff, Abdulla; García, Fernando; Martín, David; De La Escalera, Arturo; Armingol, José María

2017-01-01

One of the most challenging problems in the domain of autonomous aerial vehicles is the designing of a robust real-time obstacle detection and avoidance system. This problem is complex, especially for the micro and small aerial vehicles, that is due to the Size, Weight and Power (SWaP) constraints. Therefore, using lightweight sensors (i.e., Digital camera) can be the best choice comparing with other sensors; such as laser or radar.For real-time applications, different works are based on stereo cameras in order to obtain a 3D model of the obstacles, or to estimate their depth. Instead, in this paper, a method that mimics the human behavior of detecting the collision state of the approaching obstacles using monocular camera is proposed. The key of the proposed algorithm is to analyze the size changes of the detected feature points, combined with the expansion ratios of the convex hull constructed around the detected feature points from consecutive frames. During the Aerial Vehicle (UAV) motion, the detection algorithm estimates the changes in the size of the area of the approaching obstacles. First, the method detects the feature points of the obstacles, then extracts the obstacles that have the probability of getting close toward the UAV. Secondly, by comparing the area ratio of the obstacle and the position of the UAV, the method decides if the detected obstacle may cause a collision. Finally, by estimating the obstacle 2D position in the image and combining with the tracked waypoints, the UAV performs the avoidance maneuver. The proposed algorithm was evaluated by performing real indoor and outdoor flights, and the obtained results show the accuracy of the proposed algorithm compared with other related works. PMID:28481277

A Motion Planning Approach to Automatic Obstacle Avoidance during Concentric Tube Robot Teleoperation

PubMed Central

Torres, Luis G.; Kuntz, Alan; Gilbert, Hunter B.; Swaney, Philip J.; Hendrick, Richard J.; Webster, Robert J.; Alterovitz, Ron

2015-01-01

Concentric tube robots are thin, tentacle-like devices that can move along curved paths and can potentially enable new, less invasive surgical procedures. Safe and effective operation of this type of robot requires that the robot’s shaft avoid sensitive anatomical structures (e.g., critical vessels and organs) while the surgeon teleoperates the robot’s tip. However, the robot’s unintuitive kinematics makes it difficult for a human user to manually ensure obstacle avoidance along the entire tentacle-like shape of the robot’s shaft. We present a motion planning approach for concentric tube robot teleoperation that enables the robot to interactively maneuver its tip to points selected by a user while automatically avoiding obstacles along its shaft. We achieve automatic collision avoidance by precomputing a roadmap of collision-free robot configurations based on a description of the anatomical obstacles, which are attainable via volumetric medical imaging. We also mitigate the effects of kinematic modeling error in reaching the goal positions by adjusting motions based on robot tip position sensing. We evaluate our motion planner on a teleoperated concentric tube robot and demonstrate its obstacle avoidance and accuracy in environments with tubular obstacles. PMID:26413381

A Motion Planning Approach to Automatic Obstacle Avoidance during Concentric Tube Robot Teleoperation.

PubMed

Torres, Luis G; Kuntz, Alan; Gilbert, Hunter B; Swaney, Philip J; Hendrick, Richard J; Webster, Robert J; Alterovitz, Ron

2015-05-01

Concentric tube robots are thin, tentacle-like devices that can move along curved paths and can potentially enable new, less invasive surgical procedures. Safe and effective operation of this type of robot requires that the robot's shaft avoid sensitive anatomical structures (e.g., critical vessels and organs) while the surgeon teleoperates the robot's tip. However, the robot's unintuitive kinematics makes it difficult for a human user to manually ensure obstacle avoidance along the entire tentacle-like shape of the robot's shaft. We present a motion planning approach for concentric tube robot teleoperation that enables the robot to interactively maneuver its tip to points selected by a user while automatically avoiding obstacles along its shaft. We achieve automatic collision avoidance by precomputing a roadmap of collision-free robot configurations based on a description of the anatomical obstacles, which are attainable via volumetric medical imaging. We also mitigate the effects of kinematic modeling error in reaching the goal positions by adjusting motions based on robot tip position sensing. We evaluate our motion planner on a teleoperated concentric tube robot and demonstrate its obstacle avoidance and accuracy in environments with tubular obstacles.

Harnessing atomistic simulations to predict the rate at which dislocations overcome obstacles

NASA Astrophysics Data System (ADS)

Saroukhani, S.; Nguyen, L. D.; Leung, K. W. K.; Singh, C. V.; Warner, D. H.

2016-05-01

Predicting the rate at which dislocations overcome obstacles is key to understanding the microscopic features that govern the plastic flow of modern alloys. In this spirit, the current manuscript examines the rate at which an edge dislocation overcomes an obstacle in aluminum. Predictions were made using different popular variants of Harmonic Transition State Theory (HTST) and compared to those of direct Molecular Dynamics (MD) simulations. The HTST predictions were found to be grossly inaccurate due to the large entropy barrier associated with the dislocation-obstacle interaction. Considering the importance of finite temperature effects, the utility of the Finite Temperature String (FTS) method was then explored. While this approach was found capable of identifying a prominent reaction tube, it was not capable of computing the free energy profile along the tube. Lastly, the utility of the Transition Interface Sampling (TIS) approach was explored, which does not need a free energy profile and is known to be less reliant on the choice of reaction coordinate. The TIS approach was found capable of accurately predicting the rate, relative to direct MD simulations. This finding was utilized to examine the temperature and load dependence of the dislocation-obstacle interaction in a simple periodic cell configuration. An attractive rate prediction approach combining TST and simple continuum models is identified, and the strain rate sensitivity of individual dislocation obstacle interactions is predicted.

Assistive obstacle detection and navigation devices for vision-impaired users.

PubMed

Ong, S K; Zhang, J; Nee, A Y C

2013-09-01

Quality of life for the visually impaired is an urgent worldwide issue that needs to be addressed. Obstacle detection is one of the most important navigation tasks for the visually impaired. In this research, a novel range sensor placement scheme is proposed in this paper for the development of obstacle detection devices. Based on this scheme, two prototypes have been developed targeting at different user groups. This paper discusses the design issues, functional modules and the evaluation tests carried out for both prototypes. Implications for Rehabilitation Visual impairment problem is becoming more severe due to the worldwide ageing population. Individuals with visual impairment require assistance from assistive devices in daily navigation tasks. Traditional assistive devices that assist navigation may have certain drawbacks, such as the limited sensing range of a white cane. Obstacle detection devices applying the range sensor technology can identify road conditions with a higher sensing range to notify the users of potential dangers in advance.

Recovering an elastic obstacle containing embedded objects by the acoustic far-field measurements

NASA Astrophysics Data System (ADS)

Qu, Fenglong; Yang, Jiaqing; Zhang, Bo

2018-01-01

Consider the inverse scattering problem of time-harmonic acoustic waves by a 3D bounded elastic obstacle which may contain embedded impenetrable obstacles inside. We propose a novel and simple technique to show that the elastic obstacle can be uniquely recovered by the acoustic far-field pattern at a fixed frequency, disregarding its contents. Our method is based on constructing a well-posed modified interior transmission problem on a small domain and makes use of an a priori estimate for both the acoustic and elastic wave fields in the usual H 1-norm. In the case when there is no obstacle embedded inside the elastic body, our method gives a much simpler proof for the uniqueness result obtained previously in the literature (Natroshvili et al 2000 Rend. Mat. Serie VII 20 57-92 Monk and Selgas 2009 Inverse Problems Imaging 3 173-98).

Cross-Cultural Contact in Counseling Training.

ERIC Educational Resources Information Center

Diaz-Lazaro, Carlos M.; Cohen, B. Beth

2001-01-01

Reports on the importance of cross-cultural contact in the development of multicultural counseling competencies (MCCs). Results reveal that the greater the prior cross-cultural life experience, the higher were students' MCCs measured at the beginning of a multicultural counseling course. MCCs measured at the end of the course were significantly…

Fresnel diffraction by spherical obstacles

NASA Technical Reports Server (NTRS)

Hovenac, Edward A.

1989-01-01

Lommel functions were used to solve the Fresnel-Kirchhoff diffraction integral for the case of a spherical obstacle. Comparisons were made between Fresnel diffraction theory and Mie scattering theory. Fresnel theory is then compared to experimental data. Experiment and theory typically deviated from one another by less than 10 percent. A unique experimental setup using mercury spheres suspended in a viscous fluid significantly reduced optical noise. The major source of error was due to the Gaussian-shaped laser beam.

Age-related changes in gait adaptability in response to unpredictable obstacles and stepping targets.

PubMed

Caetano, Maria Joana D; Lord, Stephen R; Schoene, Daniel; Pelicioni, Paulo H S; Sturnieks, Daina L; Menant, Jasmine C

2016-05-01

A large proportion of falls in older people occur when walking. Limitations in gait adaptability might contribute to tripping; a frequently reported cause of falls in this group. To evaluate age-related changes in gait adaptability in response to obstacles or stepping targets presented at short notice, i.e.: approximately two steps ahead. Fifty older adults (aged 74±7 years; 34 females) and 21 young adults (aged 26±4 years; 12 females) completed 3 usual gait speed (baseline) trials. They then completed the following randomly presented gait adaptability trials: obstacle avoidance, short stepping target, long stepping target and no target/obstacle (3 trials of each). Compared with the young, the older adults slowed significantly in no target/obstacle trials compared with the baseline trials. They took more steps and spent more time in double support while approaching the obstacle and stepping targets, demonstrated poorer stepping accuracy and made more stepping errors (failed to hit the stepping targets/avoid the obstacle). The older adults also reduced velocity of the two preceding steps and shortened the previous step in the long stepping target condition and in the obstacle avoidance condition. Compared with their younger counterparts, the older adults exhibited a more conservative adaptation strategy characterised by slow, short and multiple steps with longer time in double support. Even so, they demonstrated poorer stepping accuracy and made more stepping errors. This reduced gait adaptability may place older adults at increased risk of falling when negotiating unexpected hazards. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance Impact of Deflagration to Detonation Transition Enhancing Obstacles

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Schauer, Frederick; Hopper, David

2012-01-01

A sub-model is developed to account for the drag and heat transfer enhancement resulting from deflagration-to-detonation (DDT) inducing obstacles commonly used in pulse detonation engines (PDE). The sub-model is incorporated as a source term in a time-accurate, quasi-onedimensional, CFD-based PDE simulation. The simulation and sub-model are then validated through comparison with a particular experiment in which limited DDT obstacle parameters were varied. The simulation is then used to examine the relative contributions from drag and heat transfer to the reduced thrust which is observed. It is found that heat transfer is far more significant than aerodynamic drag in this particular experiment.

Micro air vehicle autonomous obstacle avoidance from stereo-vision

NASA Astrophysics Data System (ADS)

Brockers, Roland; Kuwata, Yoshiaki; Weiss, Stephan; Matthies, Lawrence

2014-06-01

We introduce a new approach for on-board autonomous obstacle avoidance for micro air vehicles flying outdoors in close proximity to structure. Our approach uses inverse-range, polar-perspective stereo-disparity maps for obstacle detection and representation, and deploys a closed-loop RRT planner that considers flight dynamics for trajectory generation. While motion planning is executed in 3D space, we reduce collision checking to a fast z-buffer-like operation in disparity space, which allows for significant speed-up compared to full 3d methods. Evaluations in simulation illustrate the robustness of our approach, whereas real world flights under tree canopy demonstrate the potential of the approach.

Peptide cross-reactivity: the original sin of vaccines.

PubMed

Kanduc, Darja

2012-06-01

Recent numerous studies have demonstrated that an extensive peptide identity platform characterizes entities spanning the entire evolutionary arc from viruses to humans and establishes an immune cross-reactivity potential among viruses and bacteria, as well as between microbial organisms and humans. This peptide commonality presents obstacles to diagnostics, burdens therapeutic vaccinology with harmful collateral effects, and can result in autoimmune diseases. The present study 1) recapitulates the significance of cross-reactivity from the molecular mimicry hypothesis to the phenomenon of microbial immunoevasion; 2) analyzes the implications of cross-reactivity for the self-nonself discrimination issue; 3) highlights the negative role exerted by cross-reactions in translating immunology to effective vaccines; 4) outlines the vicious circle connecting peptide commonality, microbial immune escape, adjuvanted vaccines and autoimmune cross-reactions; and 5) conclusively indicates sequence uniqueness as a basic criterion for designing effective vaccines exempt from autoimmune cross-reactions.

Obstacles and challenges following the partial decriminalisation of abortion in Colombia.

PubMed

Amado, Eduardo Díaz; Calderón García, Maria Cristina; Cristancho, Katherine Romero; Salas, Elena Prada; Hauzeur, Eliane Barreto

2010-11-01

During a highly contested process, abortion was partially decriminalised in Colombia in 2006 by the Constitutional Court: when the pregnancy threatens a woman's life or health, in cases of severe fetal malformations incompatible with life, and in cases of rape, incest or unwanted insemination. However, Colombian women still face obstacles to accessing abortion services. This is illustrated by 36 cases of women who in 2006-08 were denied the right to a lawful termination of pregnancy, or had unjustified obstacles put in their path which delayed the termination, which are analysed in this article. We argue that the obstacles resulted from fundamental disagreements about abortion and misunderstandings regarding the ethical, legal and medical requirements arising from the Court's decision. In order to avoid obstacles such as demands for a judge's authorisation, institutional claims of conscientious objection, rejection of a claim of rape, or refusal of health insurance coverage for a legal termination, which constitute discrimination against women, three main strategies are suggested: public ownership of the Court's decision by all Colombian citizens, a professional approach by those involved in the provision of services in line with the law, and monitoring of its implementation by governmental and non-governmental organisations. Copyright © 2010 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

Characterizing Laminar Flame Interactions with Turbulent Fluidic Jets and Solid Obstacles for Turbulence Induction

NASA Astrophysics Data System (ADS)

Gerdts, Stephen; Chambers, Jessica; Ahmed, Kareem

2016-11-01

A detonation engine's fundamental design concept focuses on enhancing the Deflagration to Detonation Transition (DDT), the process through which subsonic flames accelerate to form a spontaneous detonation wave. Flame acceleration is driven by turbulent interactions that expand the reaction zone and induce mixing of products and reactants. Turbulence in a duct can be generated using solid obstructions, fluidic obstacles, duct angle changes, and wall skin friction. Solid obstacles have been previously explored and offer repeatable turbulence induction at the cost of pressure losses and additional system weight. Fluidic jet obstacles are a novel technique that provide advantages such as the ability to be throttled, allowing for active control of combustion modes. The scope of the present work is to expand the experimental database of varying parameters such as main flow and jet equivalence ratios, fluidic momentum ratios, and solid obstacle blockage ratios. Schlieren flow visualization and particle image velocimetry (PIV) are employed to investigate turbulent flame dynamics throughout the interaction. Optimum conditions that lead to flame acceleration for both solid and fluidic obstacles will be determined. American Chemical Society.

Obstacle Classification and 3D Measurement in Unstructured Environments Based on ToF Cameras

PubMed Central

Yu, Hongshan; Zhu, Jiang; Wang, Yaonan; Jia, Wenyan; Sun, Mingui; Tang, Yandong

2014-01-01

Inspired by the human 3D visual perception system, we present an obstacle detection and classification method based on the use of Time-of-Flight (ToF) cameras for robotic navigation in unstructured environments. The ToF camera provides 3D sensing by capturing an image along with per-pixel 3D space information. Based on this valuable feature and human knowledge of navigation, the proposed method first removes irrelevant regions which do not affect robot's movement from the scene. In the second step, regions of interest are detected and clustered as possible obstacles using both 3D information and intensity image obtained by the ToF camera. Consequently, a multiple relevance vector machine (RVM) classifier is designed to classify obstacles into four possible classes based on the terrain traversability and geometrical features of the obstacles. Finally, experimental results in various unstructured environments are presented to verify the robustness and performance of the proposed approach. We have found that, compared with the existing obstacle recognition methods, the new approach is more accurate and efficient. PMID:24945679

Public cardiopulmonary resuscitation training rates and awareness of hands-only cardiopulmonary resuscitation: a cross-sectional survey of Victorians.

PubMed

Bray, Janet E; Smith, Karen; Case, Rosalind; Cartledge, Susie; Straney, Lahn; Finn, Judith

2017-04-01

To provide contemporary Australian data on the public's training in cardiopulmonary resuscitation (CPR) and awareness of hands-only CPR. A cross-sectional telephone survey in April 2016 of adult residents of the Australian state of Victoria was conducted. Primary outcomes were rates of CPR training and awareness of hands-only CPR. Of the 404 adults surveyed (mean age 55 ± 17 years, 59% female, 73% metropolitan residents), 274 (68%) had undergone CPR training. Only 50% (n = 201) had heard of hands-only CPR, with most citing first-aid courses (41%) and media (36%) as sources of information. Of those who had undergone training, the majority had received training more than 5 years previously (52%) and only 28% had received training or refreshed training in the past 12 months. Most received training in a formal first-aid class (43%), and received training as a requirement for work (67%). The most common reasons for not having training were: they had never thought about it (59%), did not have time (25%) and did not know where to learn (15%). Compared to standard CPR, a greater proportion of respondents were willing to provide hands-only CPR for strangers (67% vs 86%, P < 0.001). From an Australian perspective, there is still room for improvement in CPR training rates and awareness of hands-only CPR. Further promotion of hands-only CPR and self-instruction (e.g. DVD kits or online) may see further improvements in CPR training and bystander CPR rates. © 2017 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Does ipsilateral corticospinal excitability play a decisive role in the cross-education effect caused by unilateral resistance training? A systematic review.

PubMed

Colomer-Poveda, D; Romero-Arenas, S; Hortobagyi, T; Márquez, G

2018-01-02

Unilateral resistance training has been shown to improve muscle strength in both the trained and the untrained limb. One of the most widely accepted theories is that this improved performance is due to nervous system adaptations, specifically in the primary motor cortex. According to this hypothesis, increased corticospinal excitability (CSE), measured with transcranial magnetic stimulation, is one of the main adaptations observed following prolonged periods of training. The principal aim of this review is to determine the degree of adaptation of CSE and its possible functional association with increased strength in the untrained limb. We performed a systematic literature review of studies published between January 1970 and December 2016, extracted from Medline (via PubMed), Ovid, Web of Science, and Science Direct online databases. The search terms were as follows: (transcranial magnetic stimulation OR excitability) AND (strength training OR resistance training OR force) AND (cross transfer OR contralateral limb OR cross education). A total of 10 articles were found. Results regarding increased CSE were inconsistent. Although the possibility that the methodology had a role in this inconsistency cannot be ruled out, the results appear to suggest that there may not be a functional association between increases in muscle strength and in CSE. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Blindness enhances auditory obstacle circumvention: Assessing echolocation, sensory substitution, and visual-based navigation

PubMed Central

Scarfe, Amy C.; Moore, Brian C. J.; Pardhan, Shahina

2017-01-01

Performance for an obstacle circumvention task was assessed under conditions of visual, auditory only (using echolocation) and tactile (using a sensory substitution device, SSD) guidance. A Vicon motion capture system was used to measure human movement kinematics objectively. Ten normally sighted participants, 8 blind non-echolocators, and 1 blind expert echolocator navigated around a 0.6 x 2 m obstacle that was varied in position across trials, at the midline of the participant or 25 cm to the right or left. Although visual guidance was the most effective, participants successfully circumvented the obstacle in the majority of trials under auditory or SSD guidance. Using audition, blind non-echolocators navigated more effectively than blindfolded sighted individuals with fewer collisions, lower movement times, fewer velocity corrections and greater obstacle detection ranges. The blind expert echolocator displayed performance similar to or better than that for the other groups using audition, but was comparable to that for the other groups using the SSD. The generally better performance of blind than of sighted participants is consistent with the perceptual enhancement hypothesis that individuals with severe visual deficits develop improved auditory abilities to compensate for visual loss, here shown by faster, more fluid, and more accurate navigation around obstacles using sound. PMID:28407000

Blindness enhances auditory obstacle circumvention: Assessing echolocation, sensory substitution, and visual-based navigation.

PubMed

Kolarik, Andrew J; Scarfe, Amy C; Moore, Brian C J; Pardhan, Shahina

2017-01-01

Performance for an obstacle circumvention task was assessed under conditions of visual, auditory only (using echolocation) and tactile (using a sensory substitution device, SSD) guidance. A Vicon motion capture system was used to measure human movement kinematics objectively. Ten normally sighted participants, 8 blind non-echolocators, and 1 blind expert echolocator navigated around a 0.6 x 2 m obstacle that was varied in position across trials, at the midline of the participant or 25 cm to the right or left. Although visual guidance was the most effective, participants successfully circumvented the obstacle in the majority of trials under auditory or SSD guidance. Using audition, blind non-echolocators navigated more effectively than blindfolded sighted individuals with fewer collisions, lower movement times, fewer velocity corrections and greater obstacle detection ranges. The blind expert echolocator displayed performance similar to or better than that for the other groups using audition, but was comparable to that for the other groups using the SSD. The generally better performance of blind than of sighted participants is consistent with the perceptual enhancement hypothesis that individuals with severe visual deficits develop improved auditory abilities to compensate for visual loss, here shown by faster, more fluid, and more accurate navigation around obstacles using sound.

Leadership training in a family medicine residency program: Cross-sectional quantitative survey to inform curriculum development.

PubMed

Gallagher, Erin; Moore, Ainsley; Schabort, Inge

2017-03-01

To assess the current status of leadership training as perceived by family medicine residents to inform the development of a formal leadership curriculum. Cross-sectional quantitative survey. Department of Family Medicine at McMaster University in Hamilton, Ont, in December 2013. A total of 152 first- and second-year family medicine residents. Family medicine residents' attitudes toward leadership, perceived level of training in various leadership domains, and identified opportunities for leadership training. Overall, 80% (152 of 190) of residents completed the survey. On a Likert scale (1 = strongly disagree, 4 = neutral, 7 = strongly agree), residents rated the importance of physician leadership in the clinical setting as high (6.23 of 7), whereas agreement with the statement "I am a leader" received the lowest rating (5.28 of 7). At least 50% of residents desired more training in the leadership domains of personal mastery, mentorship and coaching, conflict resolution, teaching, effective teamwork, administration, ideals of a healthy workplace, coalitions, and system transformation. At least 50% of residents identified behavioural sciences seminars, a lecture and workshop series, and a retreat as opportunities to expand leadership training. The concept of family physicians as leaders resonated highly with residents. Residents desired more personal and system-level leadership training. They also identified ways that leadership training could be expanded in the current curriculum and developed in other areas. The information gained from this survey might facilitate leadership development among residents through application of its results in a formal leadership curriculum. Copyright© the College of Family Physicians of Canada.

Abramovo Counterterrorism Training Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, Christopher M; Ross, Larry; Lingenfelter, Forrest E

2011-01-01

The U.S. government has been assisting the Russian Federation (RF) Ministry of Defense (MOD) for many years with nuclear weapons transportation security (NWTS) through the provision of specialized guard escort railcars and cargo railcars with integrated physical security and communication systems, armored transport vehicles, and armored escort vehicles. As a natural continuation of the NWTS program, a partnership has been formed to construct a training center that will provide counterterrorism training to personnel in all branches of the RF MOD. The Abramovo Counterterrorism Training Center (ACTC) is a multinational, multiagency project with funding from Canada, RF and the U.S. Departmentsmore » of Defense and Energy. ACTC will be a facility where MOD personnel can conduct basic through advanced training in various security measures to protect Category IA material against the threat of terrorist attack. The training will enhance defense-in-depth principles by integrating MOD guard force personnel into the overall physical protection systems and improving their overall response time and neutralization capabilities. The ACTC project includes infrastructure improvements, renovation of existing buildings, construction of new buildings, construction of new training facilities, and provision of training and other equipment. Classroom training will be conducted in a renovated training building. Basic and intermediate training will be conducted on three different security training areas where various obstacles and static training devices will be constructed. The central element of ACTC, where advanced training will be held, is the 'autodrome,' a 3 km road along which various terrorist events can be staged to challenge MOD personnel in realistic and dynamic nuclear weapons transportation scenarios. This paper will address the ACTC project elements and the vision for training development and integrating this training into actual nuclear weapons transportation operations.« less

77 FR 50014 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

... navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed.... Intl. 20-Sep-12 TX Houston Sugar Land Rgnl.... 2/8058 7/19/12 TAKEOFF MINIMUMS AND (OBSTACLE) DP, Amdt...

Identifying Obstacles to Adoption in New York State's Out-of-Home Care System.

ERIC Educational Resources Information Center

Avery, Rosemary J.

1999-01-01

This study queried caseworkers for 77 New York children in out-of-home care still waiting for placement to determine obstacles to permanent adoption. Questionnaires sought demographics, placement efforts, and caseworker opinions. Findings indicated several obstacles, including the following: child's strong emotional ties to family (foster or…

Critical Care Nurses' Perceptions of End-of-Life Care Obstacles: Comparative 17-Year Data.

PubMed

Beckstrand, Renea L; Lamoreaux, Nicole; Luthy, Karlen E; Macintosh, Janelle L B

Nurses working in intensive care units (ICUs) frequently care for patients and their families at the end of life (EOL). Providing high-quality EOL care is important for both patients and families, yet ICU nurses face many obstacles that hinder EOL care. Researchers have identified various ICU nurse-perceived obstacles, but no studies have been found addressing the progress that has been made for the last 17 years. The aims of this study were to determine the most common and current obstacles in EOL care as perceived by ICU nurses and then to evaluate whether meaningful changes have occurred since data were first gathered in 1998. A quantitative-qualitative mixed methods design was used. A random, geographically dispersed sample of 2000 members of the American Association of Critical-Care Nurses was surveyed. Five obstacle items increased in mean score and rank as compared with 1999 data including (1) family not understanding what the phrase "lifesaving measures" really means, (2) providing lifesaving measures at families' requests despite patient's advance directive listing no such care, (3) family not accepting patient's poor prognosis, (4) family members fighting about the use of life support, and (5) not enough time to provide EOL care because the nurse is consumed with lifesaving measures attempting to save the patient's life. Five obstacle items decreased in mean score and rank compared with 1999 data including (1) physicians differing in opinion about care of the patient, (2) family and friends who continually call the nurse rather than calling the designated family member, (3) physicians who are evasive and avoid families, (4) nurses having to deal with angry families, and (5) nurses not knowing their patient's wishes regarding continuing with tests and treatments. Obstacles in EOL care, as perceived by critical care nurses, still exist. Family-related obstacles have increased over time. Obstacles related to families may not be easily overcome as each family

Mesoscale Thermodynamic Analysis of Atomic-Scale Dislocation-Obstacle Interactions Simulated by Molecular Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monet, Giath; Bacon, David J; Osetskiy, Yury N

2010-01-01

Given the time and length scales in molecular dynamics (MD) simulations of dislocation-defect interactions, quantitative MD results cannot be used directly in larger scale simulations or compared directly with experiment. A method to extract fundamental quantities from MD simulations is proposed here. The first quantity is a critical stress defined to characterise the obstacle resistance. This mesoscopic parameter, rather than the obstacle 'strength' designed for a point obstacle, is to be used for an obstacle of finite size. At finite temperature, our analyses of MD simulations allow the activation energy to be determined as a function of temperature. The resultsmore » confirm the proportionality between activation energy and temperature that is frequently observed by experiment. By coupling the data for the activation energy and the critical stress as functions of temperature, we show how the activation energy can be deduced at a given value of the critical stress.« less

Prevention 0f Unwanted Free-Declaration of Static Obstacles in Probability Occupancy Grids

NASA Astrophysics Data System (ADS)

Krause, Stefan; Scholz, M.; Hohmann, R.

2017-10-01

Obstacle detection and avoidance are major research fields in unmanned aviation. Map based obstacle detection approaches often use discrete world representations such as probabilistic grid maps to fuse incremental environment data from different views or sensors to build a comprehensive representation. The integration of continuous measurements into a discrete representation can result in rounding errors which, in turn, leads to differences between the artificial model and real environment. The cause of these deviations is a low spatial resolution of the world representation comparison to the used sensor data. Differences between artificial representations which are used for path planning or obstacle avoidance and the real world can lead to unexpected behavior up to collisions with unmapped obstacles. This paper presents three approaches to the treatment of errors that can occur during the integration of continuous laser measurement in the discrete probabilistic grid. Further, the quality of the error prevention and the processing performance are compared with real sensor data.

78 FR 54564 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-05

... Linder Rgnl, Takeoff Minimums and Obstacle DP, Amdt 1 Venice, FL, Venice Muni, RNAV (GPS) RWY 5, Orig Venice, FL, Venice Muni, RNAV (GPS) RWY 23, Orig Venice, FL, Venice Muni, Takeoff Minimums and Obstacle...

Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

PubMed

Qiu, Huaxin; Duan, Haibin

2017-11-01

Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Obstacle avoidance in social groups: new insights from asynchronous models

PubMed Central

Croft, Simon; Budgey, Richard; Pitchford, Jonathan W.; Wood, A. Jamie

2015-01-01

For moving animals, the successful avoidance of hazardous obstacles is an important capability. Despite this, few models of collective motion have addressed the relationship between behavioural and social features and obstacle avoidance. We develop an asynchronous individual-based model for social movement which allows social structure within groups to be included. We assess the dynamics of group navigation and resulting collision risk in the context of information transfer through the system. In agreement with previous work, we find that group size has a nonlinear effect on collision risk. We implement examples of possible network structures to explore the impact social preferences have on collision risk. We show that any social heterogeneity induces greater obstacle avoidance with further improvements corresponding to groups containing fewer influential individuals. The model provides a platform for both further theoretical investigation and practical application. In particular, we argue that the role of social structures within bird flocks may have an important role to play in assessing the risk of collisions with wind turbines, but that new methods of data analysis are needed to identify these social structures. PMID:25833245

Mental Rotation: Cross-Task Training and Generalization

ERIC Educational Resources Information Center

Stransky, Debi; Wilcox, Laurie M.; Dubrowski, Adam

2010-01-01

It is well established that performance on standard mental rotation tasks improves with training (Peters et al., 1995), but thus far there is little consensus regarding the degree of transfer to other tasks which also involve mental rotation. In Experiment 1, we assessed the effect of mental rotation training on participants' Mental Rotation Test…

Analysis of the obstacles related to treatment entry, adherence and drop-out among alcoholic patients.

PubMed

Fonsi Elbreder, Márcia; Carvalho De Humerez, Dorisdaia; Laranjeira, Ronaldo

2009-01-01

Alcoholism is a complex syndrome involving social, psychological and individual factors in addition to a series of obstacles regarding treatment entry, adherence, and drop-out. These obstacles contribute negatively to both clinical evolution and prognosis of the patients, affecting their quality of life and raising the social costs. This is a bibliographical study in which we address this theme as well as other experiences observed in our daily practice in the Alcohol and Drug Research Unit (UNIAD) based at the Federal University of São Paulo (UNIFESP). The analysis of the obstacles related to treatment entry, attendance, and drop-out among alcoholic patients shows that systemic, social, cultural, and individual factors are all involved, including the structural ones. Women have more obstacles compared to men, and what is thought to be a barrier to one patient may be a factor motivating another patient to search for help. We conclude that several factors at different levels exist that prevent the patient from overcoming these treatment obstacles.

75 FR 72942 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

..., Takeoff Minimums and Obstacle DP, Amdt 3 Harvard, NE, Harvard State, RNAV (GPS) RWY 35, Orig Harvard, NE, Harvard State, Takeoff Minimums and Obstacle DP, Orig Harvard, NE, Harvard State, VOR/DME RNAV OR GPS RWY...

Exercise Capacity and Response to Training Quantitative Trait Loci in a NZW X 129S1 Intercross and Combined Cross Analysis of Inbred Mouse Strains

PubMed Central

Massett, Michael P.; Avila, Joshua J.; Kim, Seung Kyum

2015-01-01

Genetic factors determining exercise capacity and the magnitude of the response to exercise training are poorly understood. The aim of this study was to identify quantitative trait loci (QTL) associated with exercise training in mice. Based on marked differences in training responses in inbred NZW (-0.65 ± 1.73 min) and 129S1 (6.18 ± 3.81 min) mice, a reciprocal intercross breeding scheme was used to generate 285 F2 mice. All F2 mice completed an exercise performance test before and after a 4-week treadmill running program, resulting in an increase in exercise capacity of 1.54 ± 3.69 min (range = -10 to +12 min). Genome-wide linkage scans were performed for pre-training, post-training, and change in run time. For pre-training exercise time, suggestive QTL were identified on Chromosomes 5 (57.4 cM, 2.5 LOD) and 6 (47.8 cM, 2.9 LOD). A significant QTL for post-training exercise capacity was identified on Chromosome 5 (43.4 cM, 4.1 LOD) and a suggestive QTL on Chromosomes 1 (55.7 cM, 2.3 LOD) and 8 (66.1 cM, 2.2 LOD). A suggestive QTL for the change in run time was identified on Chromosome 6 (37.8 cM, 2.7 LOD). To identify shared QTL, this data set was combined with data from a previous F2 cross between B6 and FVB strains. In the combined cross analysis, significant novel QTL for pre-training exercise time and change in exercise time were identified on Chromosome 12 (54.0 cM, 3.6 LOD) and Chromosome 6 (28.0 cM, 3.7 LOD), respectively. Collectively, these data suggest that combined cross analysis can be used to identify novel QTL and narrow the confidence interval of QTL for exercise capacity and responses to training. Furthermore, these data support the use of larger and more diverse mapping populations to identify the genetic basis for exercise capacity and responses to training. PMID:26710100

Energy dissipation by submarine obstacles during landslide impact on reservoir - potentially avoiding catastrophic dam collapse

NASA Astrophysics Data System (ADS)

Kafle, Jeevan; Kattel, Parameshwari; Mergili, Martin; Fischer, Jan-Thomas; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

2017-04-01

Dense geophysical mass flows such as landslides, debris flows and debris avalanches may generate super tsunami waves as they impact water bodies such as the sea, hydraulic reservoirs or mountain lakes. Here, we apply a comprehensive and general two-phase, physical-mathematical mass flow model (Pudasaini, 2012) that consists of non-linear and hyperbolic-parabolic partial differential equations for mass and momentum balances, and present novel, high-resolution simulation results for two-phase flows, as a mixture of solid grains and viscous fluid, impacting fluid reservoirs with obstacles. The simulations demonstrate that due to the presence of different obstacles in the water body, the intense flow-obstacle-interaction dramatically reduces the flow momentum resulting in the rapid energy dissipation around the obstacles. With the increase of obstacle height overtopping decreases but, the deflection and capturing (holding) of solid mass increases. In addition, the submarine solid mass is captured by the multiple obstacles and the moving mass decreases both in amount and speed as each obstacle causes the flow to deflect into two streams and also captures a portion of it. This results in distinct tsunami and submarine flow dynamics with multiple surface water and submarine debris waves. This novel approach can be implemented in open source GIS modelling framework r.avaflow, and be applied in hazard mitigation, prevention and relevant engineering or environmental tasks. This might be in particular for process chains, such as debris impacts in lakes and subsequent overtopping. So, as the complex flow-obstacle-interactions strongly and simultaneously dissipate huge energy at impact such installations potentially avoid great threat against the integrity of the dam. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

Object classification for obstacle avoidance

NASA Astrophysics Data System (ADS)

Regensburger, Uwe; Graefe, Volker

1991-03-01

Object recognition is necessary for any mobile robot operating autonomously in the real world. This paper discusses an object classifier based on a 2-D object model. Obstacle candidates are tracked and analyzed false alarms generated by the object detector are recognized and rejected. The methods have been implemented on a multi-processor system and tested in real-world experiments. They work reliably under favorable conditions but sometimes problems occur e. g. when objects contain many features (edges) or move in front of structured background.

Thermal activation of dislocations in large scale obstacle bypass

NASA Astrophysics Data System (ADS)

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; Martinez, Enrique

2017-08-01

Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented.

Effects of soft interactions and bound mobility on diffusion in crowded environments: a model of sticky and slippery obstacles

NASA Astrophysics Data System (ADS)

Stefferson, Michael W.; Norris, Samantha L.; Vernerey, Franck J.; Betterton, Meredith D.; E Hough, Loren

2017-08-01

Crowded environments modify the diffusion of macromolecules, generally slowing their movement and inducing transient anomalous subdiffusion. The presence of obstacles also modifies the kinetics and equilibrium behavior of tracers. While previous theoretical studies of particle diffusion have typically assumed either impenetrable obstacles or binding interactions that immobilize the particle, in many cellular contexts bound particles remain mobile. Examples include membrane proteins or lipids with some entry and diffusion within lipid domains and proteins that can enter into membraneless organelles or compartments such as the nucleolus. Using a lattice model, we studied the diffusive movement of tracer particles which bind to soft obstacles, allowing tracers and obstacles to occupy the same lattice site. For sticky obstacles, bound tracer particles are immobile, while for slippery obstacles, bound tracers can hop without penalty to adjacent obstacles. In both models, binding significantly alters tracer motion. The type and degree of motion while bound is a key determinant of the tracer mobility: slippery obstacles can allow nearly unhindered diffusion, even at high obstacle filling fraction. To mimic compartmentalization in a cell, we examined how obstacle size and a range of bound diffusion coefficients affect tracer dynamics. The behavior of the model is similar in two and three spatial dimensions. Our work has implications for protein movement and interactions within cells.

The Effects of a 10-day Altitude Training Camp at 1828 Meters on Varsity Cross-Country Runners

PubMed Central

DIEBEL, SEBASTIAN R.; NEWHOUSE, IAN; THOMPSON, DAVID S.; JOHNSON, VINEET B.K.

2017-01-01

Altitude training has been shown to alter blood lactate (BL) levels due to alterations resulting from acclimatization. This study aims to estimate the impact of altitude training on BL changes immediately following an incremental treadmill test and during recovery before and after 10-day altitude training at approximately 1828 meters. Eight varsity cross-country runners performed an incremental treadmill test (ITT), pre and post-altitude training. Resting and post-warm-up BL values were recorded. During ITT, heart rate (HR), oxygen saturation (SpO2), and time to exhaustion were monitored. BL was also measured post-ITT at 0, 2, 4, 6, and 8 minutes. The average of all BL values was higher following altitude intervention (8.8 ± 4.6 mmol/L) compared to pre-intervention (7.4 ± 3.3 mmol/L). These differences were statistically significant (t(6) = −2.40, p = .026). BL immediately (0 minutes) after the ITT was higher following the altitude intervention (13.6 ± 3.6 mmol/L) compared to pre-intervention (9.7 ± 3.8 mmol/L) and was statistically significant (t(7) = −3.30, p = .006). Average HR during the ITT was lower following the altitude intervention (176.9 ± 11.1 bpm) compared to pre (187 ± 9.5 bpm), these differences were statistically significant (t(28)= 18.07, p= <.001. Time to exhaustion was longer after the intervention, however was not statistically significant p = 0.13. These findings indicate that a 10 - day altitude intervention at 1828 meters may benefit varsity cross-country runners. The higher post-exercise BL may be attributed to more anaerobic contributions. Lower HR may suggest a larger stroke volume and/or more efficient O2 carrying capacity. PMID:28479950

A Compact Magnetic Field-Based Obstacle Detection and Avoidance System for Miniature Spherical Robots.

PubMed

Wu, Fang; Vibhute, Akash; Soh, Gim Song; Wood, Kristin L; Foong, Shaohui

2017-05-28

Due to their efficient locomotion and natural tolerance to hazardous environments, spherical robots have wide applications in security surveillance, exploration of unknown territory and emergency response. Numerous studies have been conducted on the driving mechanism, motion planning and trajectory tracking methods of spherical robots, yet very limited studies have been conducted regarding the obstacle avoidance capability of spherical robots. Most of the existing spherical robots rely on the "hit and run" technique, which has been argued to be a reasonable strategy because spherical robots have an inherent ability to recover from collisions. Without protruding components, they will not become stuck and can simply roll back after running into bstacles. However, for small scale spherical robots that contain sensitive surveillance sensors and cannot afford to utilize heavy protective shells, the absence of obstacle avoidance solutions would leave the robot at the mercy of potentially dangerous obstacles. In this paper, a compact magnetic field-based obstacle detection and avoidance system has been developed for miniature spherical robots. It utilizes a passive magnetic field so that the system is both compact and power efficient. The proposed system can detect not only the presence, but also the approaching direction of a ferromagnetic obstacle, therefore, an intelligent avoidance behavior can be generated by adapting the trajectory tracking method with the detection information. Design optimization is conducted to enhance the obstacle detection performance and detailed avoidance strategies are devised. Experimental results are also presented for validation purposes.

Control of vertical posture while elevating one foot to avoid a real or virtual obstacle.

PubMed

Ida, Hirofumi; Mohapatra, Sambit; Aruin, Alexander

2017-06-01

The purpose of this study is to investigate the control of vertical posture during obstacle avoidance in a real versus a virtual reality (VR) environment. Ten healthy participants stood upright and lifted one leg to avoid colliding with a real obstacle sliding on the floor toward a participant and with its virtual image. Virtual obstacles were delivered by a head mounted display (HMD) or a 3D projector. The acceleration of the foot, center of pressure, and electrical activity of the leg and trunk muscles were measured and analyzed during the time intervals typical for early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs). The results showed that the peak acceleration of foot elevation in the HMD condition decreased significantly when compared with that of the real and 3D projector conditions. Reduced activity of the leg and trunk muscles was seen when dealing with virtual obstacles (HMD and 3D projector) as compared with that seen when dealing with real obstacles. These effects were more pronounced during APAs and CPAs. The onsets of muscle activities in the supporting limb were seen during EPAs and APAs. The observed modulation of muscle activity and altered patterns of movement seen while avoiding a virtual obstacle should be considered when designing virtual rehabilitation protocols.

Creation of a Mental Health Treatment Fears and Obstacles Inventory for College Students

ERIC Educational Resources Information Center

Park, Heather L.; Attenweiler, William J.; Rieck, Stacey M.

2012-01-01

This project concerned the creation of an inventory for college students of treatment fears and obstacles to seeking mental health services. Unlike previous research, undergraduate participants generated a pool of items to measure fears of and obstacles to seeking services. Subsequent rational and statistical refinement resulted in a 29-item scale…

Introduction of frictional and turning function for pedestrian outflow with an obstacle.

PubMed

Yanagisawa, Daichi; Kimura, Ayako; Tomoeda, Akiyasu; Nishi, Ryosuke; Suma, Yushi; Ohtsuka, Kazumichi; Nishinari, Katsuhiro

2009-09-01

In this paper, two important factors which affect the pedestrian outflow at a bottleneck significantly are studied in detail to analyze the effect of an obstacle setup in front of an exit. One is a conflict at an exit when pedestrians evacuate from a room. We use floor field model for simulating such behavior, which is a well-studied pedestrian model using cellular automata. The conflicts have been taken into account by the friction parameter. However, the friction parameter so far is a constant and does not depend on the number of the pedestrians conflicting at the same time. Thus, we have improved the friction parameter by the frictional function, which is a function of the number of the pedestrians involved in the conflict. Second, we have presented the cost of turning of pedestrians at the exit. Since pedestrians have inertia, their walking speeds decrease when they turn and the pedestrian outflow decreases. The validity of the extended model, which includes the frictional function and the turning function, is supported by the comparison of a mean-field theory and real experiments. We have observed that the pedestrian flow increases when we put an obstacle in front of an exit in our real experiments. The analytical results clearly explains the mechanism of the effect of the obstacle, i.e., the obstacle blocks pedestrians moving to the exit and decreases the average number of pedestrians involved in the conflict. We have also found that an obstacle works more effectively when we shift it from the center since pedestrians go through the exit with less turning.

Basic science research in urology training.

PubMed