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Multisensor Map Matching for Pedestrian and Wheelchair Navigation
Published in Hassan A. Karimi, Advanced Location-Based Technologies and Services, 2016
A wheelchair’s position can be estimated based on distances measured with odometer devices mounted on both wheels of the wheelchair. Accelerometers can provide relatively high positional accuracy in a relatively short time and, due to their bias drift, the position error will grow over time. For pedestrians, positioning data can come from accelerometer measurements based on an INS or from a step-counter and step-length estimator from a typical pedometer. Accelerometer measurements used for pedestrians have the same problem as in wheelchairs, that is, position errors would be accumulated over time. Regarding pedestrian dead reckoning (PDR), the positional accuracy in the pedometer–GPS integration relies mainly on estimations of the number of steps (counted by the accelerometer) and the length of the steps (calculated by the pedometer). For a pedometer to measure distance, the average step length of a user must be measured, assuming users walk at a consistent pace.
Using accelerometry to classify physical activity intensity in older adults: What is the optimal wear-site?
Published in European Journal of Sport Science, 2020
Michael J. Duncan, Alex Rowlands, Chelsey Lawson, Sheila Leddington Wright, Matt Hill, Martyn Morris, Emma Eyre, Jason Tallis
After briefing and fitting with the monitors and gas analyser, each participant performed a series of activities reflective of different levels of PA. These were lying supine, seated reading, slow walking, medium walking, fast walking and were performed in order. Being lay supine was used to determine a resting metabolic rate for subsequent determination of METs. Participants then performed bouts of folding laundry and sweeping the floor to represent household activity and cycling at 50 Watts (Monark Ergomedic 874e, Vannsbro, Sweden), similar to prior work (Montoye, Moore, Bowles, Korycinski, & Pfeiffer, 2018a). All activities were performed for five minutes with a five-minute rest in between. Using previous protocols (Ryan & Gormley, 2013) as guidelines, walking speeds were set at 3 kmph−1(0.8 m/s), 4.5 kmph−1(1.25 m/s) and 5.5 kmph−1 (1.52 m/s) to represent slow-, medium-pace walking and fast walking, respectively. These speeds were taken from prior studies documenting treadmill walking speeds corresponding to slow, medium and brisk walking in older adults (Huijben, van Schooten, van Dieen, & Pijnappels, 2018; Parise, Sternfeld, Samuels, & Tager, 2004).
Validation of wearable activity monitors for real-time cadence
Published in Journal of Sports Sciences, 2020
Ho Han, Heontae Kim, Wei Sun, Mary Malaska, Bridget Miller
Overground walking protocol consisted of 2 main sections including (1) self-determined walking trials and (2) researcher-prescribed walking trials. For both trials, participants were asked to continuously walk a 13-m oval track (i.e., marked using 2 cones) in an indoor gymnasium for 2 min for each trial followed by a 1-min break. For the self-determined walking trials, participants walked at self-determined slow, normal, and fast walking paces. Each pace was described as: (1) slow pace: a speed that the participant would walk if they were in grocery shopping or texting while walking, (2) normal pace: typically normal everyday walking speed in free-living, and (3) fast pace: a speed that the participant would walk if they were in a hurry to get somewhere, but not as fast as power-walking. The first trial was always at the normal walking pace. The remaining sets (slow and fast) were counter-balanced. Extra time was provided at the beginning of each trial for the participants to reach their self-determined walking speed. For the researcher-prescribed walking test, participants were instructed to walk faster than 120 stepsmin−1 using each activity monitor (i.e., GM, PL, FP, and SS: 4 trials in a counter-balanced order) providing a feedback on their cadence in real-time. Same as self-determined walking trials, the participants were given an extra time to reach above 120 stepsmin−1 and asked to maintain the intensity for 2 min using the real-time cadence feedback as needed. The cadence of 120 stepsmin−1 was selected to ensure that participants walked briskly (i.e., above 3 METs) (Pillay, Kolbe-Alexander, Proper, van Mechelen, & Lambert, 2014, Rowe, Kang, Sutherland, Holbrook, & Barreira, 2013).