Spelling suggestions: "subject:"[een] CROSSING"" "subject:"[enn] CROSSING""
81 |
The Effects of High Cushioned Versus Minimal Cushioned Shoes on Dynamic Postural Stability of Older Adults During Obstacle CrossingNaghdlou, Sara 30 August 2021 (has links)
Footwear can affect postural stability in individuals, particularly in elderly people. Aging-related decline in postural stability, particularly in the mediolateral (ML) direction, is a risk factor for falls and fall-related injuries among older adults. This study aimed to investigate the effects of high cushioned and minimal shoes on dynamic postural stability in ML during obstacle crossing in defined older and younger adults. Six healthy older adults (50–60 years old, body weight: 74.8 kg, body height: 168.0 cm) and six healthy younger adults (18–32 years old, body weight: 73.8 kg, body height: 174.8 cm) participated in the study. A Vicon motion analysis system with 10 optical cameras was used to capture the obstacle (20 cm height) crossing motion of the participants at 200 Hz, and ground reaction forces of obstacle crossing were collected at 1000 Hz. Motion data of obstacle crossing were collected at three shoe conditions, namely, minimal shoe, high cushioned shoe and barefoot (control). Data from five trials of obstacle crossing for each shoe condition were processed using Vicon Nexus software 2.11.0 and Matlab R2013b. Displacement and velocity of centre of mass (COM) in the ML direction, COM–centre of pressure (COP) ML separation, step length, step velocity, toe clearance, pre-horizontal distance, hip flexion angle and hip abduction angle during obstacle crossing were examined. One-way ANOVA with pairwise analysis showed that toe clearance was significantly larger in the high cushioned shoe conditions than in the minimal shoe and barefoot conditions in older adults (high cushioned shoes vs. barefoot: p = 0.019; cushioned shoes vs. minimal shoes: p = 0.031) and younger adults (high cushioned shoes vs. barefoot: p = 0.016; high cushioned shoes vs. minimal shoes: p = 0.000). No significant difference in the measures was found between the minimal shoe and barefoot conditions in each group. Compared with older adults, younger adults showed significantly larger step length in barefoot condition (p = 0.000) and minimal shoe (p = 0.016). Independent t-test for examination of the significant difference of the means of each measure when the shoe condition was changed showed that only step length and step velocity were significantly different between older and younger adults. When the shoe condition was changed from minimal shoe or barefoot to high cushioned shoe, older adults showed significantly bigger change in step velocity (10.04 ± 4.39 cm/s for older; 1.87 ± 0.81 cm/s for younger; p = 0.034) and step length (14.26 ± 6.99 cm for older; 2.086 ± 1.13 cm for younger; p = 0.041) than younger adults. This result indicates that older adults had 23% greater total range of step length and 12% greater total range of step velocity compared with younger adults when shoe condition changed. Moreover, older adults showed 16% smaller total range in their maximal COM-COP ML separations than younger adults when shoe condition changed. It is concluded that high cushioned shoes can influence dynamic postural stability in the ML direction during obstacle crossing in younger and older adults. The minimal shoe and barefoot conditions did not show significant influence on postural stability in the ML direction during obstacle crossing in older and younger adults. The minimal shoe on dynamic postural stability in the ML direction is not significant. Age differences in dynamic postural stability in the ML direction during obstacle crossing were found at the same shoe conditions. Moreover, when shoe condition was changed, shoe cushioning conditions affected postural stability to a larger extent in older adults compared with younger adults. The high cushioned shoe led to a more challenged postural stability in adults aged 50 to 60 than younger adults aged 18 to 32.
|
82 |
Měření frekvence / Frequency measurementMilota, Martin January 2012 (has links)
The theme of this thesis is presentation of the CompactRIO platform by National Instruments with its range of hardware and the possibility of using this platform for the frequency measurement of analog signals. The result of this thesis is software equipment for this device focusing on the frequency measurement of analog signals and experimental verification of posibilities of a specific configuration of this platform in the range of measurable frequencies.
|
83 |
Úprava mimoúrovňové křižovatky Hradecká x Sportovní x Palackého / Modifying interchanges Hradecka x Sports x PalackyChlíbek, David January 2015 (has links)
Thesis subject is a project documentation as a proposal of reconstruction of level crossing in Hradecká street to elevated crossing. Proposal is based on research of traffic intensity and consequential assessment of traffic capacity. Another thesis subject is a verification of potencial proposal of elevated crossing in Sportovní street and Hradecká street, which exists only in one way in present. This proposal is only indicative and can be used for next stage of project documentation. Proposal of crossing in Hradecká and Palackého třída includes design of beam of elevated crossing and design of cover crossing. Elevated crossing of Sportovní and Hradecká is designed as a beam of crossing, which runs on bridge construction of concrete.
|
84 |
THE FREQUENCY OF AND FACTORS ASSOCIATED WITH INADVERTENT CONTACTS DURING OBSTACLE CROSSING IN OLDER ADULTSTimothy P Becker (8970635) 16 June 2020 (has links)
Occasionally healthy older adults trip over stationary objects even when seen well in advance. These are known as “inadvertent” trips. The purpose of this study was to determine the prevalence of inadvertent trips in older males and older females under conditions of normal vision with good lighting. We also determined their relationship with unobstructed gait measures and other risk factors associated with falls during everyday activities. Forty-one subjects stepped over an obstacle (height set to 25% of leg length) 100 times. The obstacle was contacted by 15 participants (37%) in a total of 29 trials (0.7% of all trials). Of the 29 obstacle contacts, 52% occurred with lead limb. There was no difference in the frequency of contacts between males and females. Slower stride speed, shorter stride length, and increased gait cycle time variability during unobstructed walking were associated with contacts during the obstacle crossing trials (p <u><</u> 0.041). Inadvertent trips were also associated with the number of prescription medications taken by participants (p = 0.019) and participants’ maximum reported rating-of-fatigue (p = 0.022<u>)</u>. Fatigue was an important factor and 36 subjects (88%) reported an increase in their fatigue across trials highlighting the importance of considering fatigue in all obstacle crossing studies using older adults. We conclude that inadvertent trips are not uncommon in older adults and point to useful future areas of research and risk factors that could be targeted by fall intervention programs
|
85 |
Optimizing Traffic Network Signals Around Railroad CrossingsZhang, Li 07 July 2000 (has links)
The dissertation proposed an approach, named "Signal Optimization Under Rail Crossing sAfety cOnstraints"(SOURCAO), to the traffic signal control near a highway rail grade crossing (HRGC). SOURCAO targets two objectives: HRGC safety improvement (a high priority national transportation goal) and highway traffic delay reduction (a common desire for virtually all of us). Communication and data availability from ITS and the next generation train control are assumed available in SOURCAO.
The first step in SOURCAO is to intelligently choose a proper preemption phase sequence to promote HRGC safety. An inference engine is designed in place of traditional traffic signal preemption calls to prevent the queue from backing onto HRGC. The potential hazard is dynamically examined as to whether any queuing vehicle stalls on railroad tracks. The inference engine chooses the appropriate phase sequence to eliminate the hazardous situation.
The second step in SOURCAO is to find the optimized phase length. The optimization process uses the network traffic delay (close to the control delay) at the intersections within HRGC vicinities as an objective function. The delay function is approximated and represented by multilayer perceptron neural network (off-line). After the function was trained and obtained, an optimization algorithm named Successive Quadratic Programming (SQP) searches the length of phases (on-line) by minimizing the delay function. The inference engine and proposed delay model in optimization take the on-line surveillance detector data and HRGC closure information as input.
By integrating artificial intelligence and optimization technologies, the independent simulation evaluation of SOURCAO by TSIS/CORSIM demonstrated that the objectives are reached. The average network delay for 20 runs of simulation evaluation is reduced over eight percent by a t-test while the safety of HRGC is promoted. The sensitivity tests demonstrate that SOURCAO works efficiently under light and heavy traffic conditions, as well as a wide range of HRGC closure times. / Ph. D.
|
86 |
Návrh rekonstrukce úseku dálnice D46 a mimoúrovňové křižovatky Vyškov / 69 / 5000 Výsledky překladu Reconstruction proposal for the section of the D46 motorway and the Vyškov level crossingKozminský, Marek January 2022 (has links)
This diploma thesis deals with proposal for reconstruction of the section of the D46 motorway and the adjacent motorway junction designated as Exit 2 Vyškov. The area in question is located in the non-built-up area of the town of Vyškov. The D46 motorway crosses first-class road number II/430 at this point, which connects with the II/430 road at the intersection. The intersection we are concerned with is plagued by several problems. The first is the unsatisfactory connection of road number II/430 in the eastern part of the intersection, where the indirect branch has no slip road, meaning that vehicles are forced to stop here, resulting in clogging of the exit from Vyškov to Olomouc. Another problem is the turn-off to the petrol station in the western part of the intersection. The problem occurs at the location of the turn-off to the previously mentioned petrol station, where approximately 100 m from the turn-off there is an indirect branch of the western part of the intersection and vehicles wishing to join the D46 motorway are forced to slow down there.
|
87 |
An Analysis of Survival Data when Hazards are not Proportional: Application to a Cancer Treatment StudyWhite, John Benjamin 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The crossing of Kaplan-Meier survival curves presents a challenge when conducting survival analysis studies, making it unclear whether any of the study groups involved present any significant difference in survival. An approach involving the determination of maximum vertical distance between the curves is considered here as a method to assess whether a survival advantage exists between different groups of patients. The method is illustrated on a dataset containing survival times of patients treated with two cancer treatment regimes, one involving treatment by chemotherapy alone, and the other by treatment with both chemotherapy and radiotherapy.
|
88 |
Spatial Modeling of Wildlife Crossing:GIS-based Approach for Identifying High-priority Locations of Defragmentation across Transport Corridors / Rumslig Modellering av Ekodukt: GIS-baserad Modellering för att identifiera Habitat Flaskhalsar Längst en Transport Korridor.Jonsson, Josefine January 2017 (has links)
In this report, connectivity modeling has been performed using land cover data to find habitat pinch-points for deer along the study area Norrortsleden in Stockholm. Norrortsleden was chosen because there are a high number of deer accidents in the area, and is a priority area for action according to a barrier analysis for deer made by the Swedish Transport Administration. After interviews and research, it was found that a tool named LinkageMapper using CircuitScape theory is one good way to find habitat pinch-points along transport corridors. Firstly, a habitat resistance raster map and zone data are needed. The habitat resistance layer was made using ground cover data and given resistance values specifically for deer. An edge-zone layer was also added on top using built-in ArcGIS tools. Lastly all the road and railway data was transformed into raster and added to the final resistance layer. To find the pinch-points in the natural habitat for deer, different settings for the ArcGIS tool LinkageMapper have been tested and variations of the zone layer have been used. LinkageMapper is an external free to download tool and uses CircuitScape theory to find habitat pinch points. Different settings were tested for a 2-zone version on a 2 km buffer on each side of the road. In addition, two main settings are available, all-to-one mode and pairwise mode in LinkageMapper. Input width must also be entered to limit the number of results. Corridor width was set to 50 m for all of the produced results. After preparation of the raw data, processing zones and resistance layers it was found that usually only one corridor was showing, so a version with 6 zones on each side of the road with a 4 km buffer was made and produced more continuous results. All of the pinch-points found were marked on a map and the ones not already near an existing wildlife passage are located just south of Lake Vallentuna. The research found that the GIS-based approach is effective for Identifying high-priority locations of defragmentation across transport corridors. Using CircuitScape theory can be a great compliment too regular least cost-path.
|
89 |
Modeling and Assessing Crossing Elimination as a Strategy to Reduce Evacuee Travel TimeJahangiri, Arash 26 February 2013 (has links)
During evacuations, emergency managers and departments of transportation seek to facilitate the movement of citizens out of impacted or threatened areas. One strategy they may consider is crossing elimination, which prohibits certain movements at intersections, that may be permissible under normal operating conditions. A few previous studies examined this strategy in conjunction with contra-flow operations, but fewer have considered crossing elimination by itself. This study helps fill the existing gap in knowledge of the individual effects of crossing elimination.
A bi-level model that iterates between optimization and simulation is developed to determine the optimal configuration of intersection movements from a set of pre-specified possible configurations for intersections in a given area. At the upper level, evacuees' travel time is minimized and at the lower level, traffic is assigned to the network with the traffic assignment-simulation software DynusT. The overall model is solved with a simulated annealing heuristic and applied to a real case study to assess the impact of crossing elimination.
Three scenarios are developed and examined using the solution method proposed in this research. These scenarios are developed using combinations of two elements: (1) Evacuee destination distributions, and (2) Evacuee departure time distributions. Results showed about 3-5 percent improvement in total evacuee travel time can be achieved in these scenarios. Availability of through movements at intersections and existing merging points in movement configurations are the two factors influencing the selection of movement configurations. / Master of Science
|
90 |
The effects of laterality on obstacle crossing performance in unilateral trans-tibial amputeesDe Asha, Alan R., Buckley, John 02 March 2015 (has links)
yes / Background
Unilateral trans-tibial amputees have bilaterally reduced toe clearance, and an increased risk of foot contact, while crossing obstacles compared to the able-bodied. While the able-bodied tend to lead with a ‘preferred’ limb it is equivocal whether amputees prefer to lead with the intact or prosthetic limb. This study determined the effects of laterality, compared to side of amputation, on amputees' obstacle crossing performance. To help understand why laterality could affect performance we also assessed knee proprioception for both limbs.
Methods
Foot placement and toe clearance parameters were recorded while nine amputees crossed obstacles of varying heights leading with both their intact and prosthetic limbs. Joint-position sense was also assessed. Participants self-reported which limb was their preferred (dominant) limb.
Findings
There were no significant differences in foot placements or toe clearance variability across lead-limb conditions. There were no significant differences in toe clearance between intact and prosthetic lead-limbs (p = 0.28) but toe clearance was significantly higher when amputees led with their preferred compared to non-preferred limb (p = 0.025). There was no difference in joint-position sense between the intact and residual knees (p = 0.34) but joint-position sense tended to be more accurate for the preferred, compared to non-preferred limb (p = 0.08).
Interpretation
Findings suggest that, despite the mechanical constraints imposed by use of a prosthesis, laterality may be as important in lower-limb amputees as it is in the able bodied. This suggests that amputees should be encouraged to cross obstacles leading with their preferred limb. / Engineering and Physical Sciences Research Council
|
Page generated in 0.5541 seconds