Hand Speed Research Articles

The Effect of Kinesiotape on Flexion-Extension of the Thoracolumbar Back in Horses at Trot.

Simple SummaryWeak back muscles and back pain are commonly seen in horses today; these problems are often caused by poor training techniques and lead to other problems such as poor performance, lameness, and pain. Veterinary treatment and/or rehabilitation is a necessity. Kinesiotaping is a commonly used treatment method in equine physiotherapy sand veterinary rehabilitation. The method theoretically stimulates the sensory pathways from the taped region that in turn modulates the neuromuscular activity and locomotor function to improve locomotion and/or range of motion (ROM). The aim of this study was to determine if kinesiotape applied to the abdominal muscles, with the intention of activating them as back flexors, would affect the ROM in flexion-extension (sagittal plane) of the thoracolumbar back of the trotting horse. Eight horses, aged 5–15 years, were included and were trotted on a straight line, 2 × 30 m, with and without kinesiotape. The differences between the two conditions were measured by an optical motion capture using reflective markers placed along the thoracolumbar spine. No statistical significance was shown between the two groups of horses; although some horses showed individual changes indicating that kinesiotape may have affected those horses. The evidence base for rehabilitation and training methods is essential, and more research is needed to understand whether there is any potential benefit of the kinesiotape.Kinesiotape theoretically stimulates mechanoreceptive and proprioceptive sensory pathways that in turn may modulate the neuromuscular activity and locomotor function, so alteration of activation, locomotion and/or range of motion (ROM) can be achieved. The aim of this study was to determine whether kinesiotape applied to the abdominal muscles would affect the ROM in flexion-extension (sagittal plane) in the thoracolumbar back of horses at trot. The study design was a paired experimental study, with convenient sample. Each horse was randomly placed in the control or the intervention group and then the order reversed. Eight horses trotted at their own preferred speed in hand on a straight line, 2 × 30 m. Optical motion capture was used to collect kinematic data. Paired t-tests, normality tests and 1-Sample Wilcoxon test were used to assess the effects of the kinesiotape. No statistical significance (p < 0.05) for changes in flexion-extension of the thoracolumbar back in trot was shown in this group of horses. Some changes were shown indicating individual movement strategies in response to stimuli from the kinesiotape. More research in this popular and clinically used method is needed to fully understand the reacting mechanisms in horses.

Assessment of bilateral motor skills and visuospatial attention in children with perinatal stroke using a robotic object hitting task

BackgroundWhile motor deficits are the hallmark of hemiparetic cerebral palsy, children may also experience impairments in visuospatial attention that interfere with participation in complex activities, including sports or driving. In this study, we used a robotic object hitting task to assess bilateral sensorimotor control and visuospatial skills in children with hemiparesis due to perinatal arterial ischemic stroke (AIS) or periventricular venous infarct (PVI). We hypothesized that performance would be impaired bilaterally and be related to motor behavior and clinical assessment of visuospatial attention.MethodsForty-nine children with perinatal stroke and hemiparetic cerebral palsy and 155 typically developing (TD) children participated in the study. Participants performed a bilateral object hitting task using the KINARM Exoskeleton Robot, in which they used virtual paddles at their fingertips to hit balls that fell from the top of the screen with increasing speed and frequency over 2.3 min. We quantified performance across 13 parameters including number of balls hit with each hand, movement speed and area, biases between hands, and spatial biases. We determined normative ranges of performance accounting for age by fitting 95% prediction bands to the TD children. We compared parameters between TD, AIS, and PVI groups using ANCOVAs accounting for age effects. Lastly, we performed regression analysis between robotic and clinical measures.ResultsThe majority of children with perinatal stroke hit fewer balls with their affected arm compared to their typically developing peers. We also found deficits with the ipsilesional (“unaffected”) arm. Children with AIS had greater impairments than PVI. Despite hitting fewer balls, we only identified 18% of children as impaired in hand speed or movement area. Performance on the Behavioral Inattention Test accounted for 21–32% of the variance in number of balls hit with the unaffected hand.ConclusionsChildren with perinatal stroke-induced hemiparetic cerebral palsy may have complex bilateral deficits reflecting a combination of impairments in motor skill and visuospatial attention. Clinical assessments and interventions should address the interplay between motor and visuospatial skills.

Dual-task performance of speech and motor skill: verb generation facilitates grasping behaviour.

Pronouncing nouns or verbs while grasping distinctly alters movement. Changes in hand speed and final position occur according to the meaning of the words spoken. These results are typically found when executing a single movement paired with a single word. For example, pronouncing the word 'fast' increased the speed of the hand when reaching to grasp. Our objective was to compare how verb and noun fluency tasks interact with grasping behaviour in a grasp-to-construct task. Because previous imaging research shows that verb and noun production activates distinct neural areas, we reasoned that grasping outcomes would differ according to the category of word produced by participants. Specifically, we hypothesized that verb pronunciation would distinctly affect grasping behaviour compared to producing nouns. We recruited 38 young adults who performed a grasp-to-construct task and two different verbal fluency tasks. Participants completed each task (grasp, verb fluency, and noun fluency) separately as control conditions, and the grasping and each speaking task simultaneously for dual-task conditions. We found that during the dual-task condition, when generating nouns and grasping, participants made significantly more grasping errors (inaccurate grasps) compared to the control and verb dual-task conditions. Moreover, our results revealed a relationship between the number of verbs generated and grasping performance. Participants who generated more verbs were faster and more accurate during the motor component of the dual-task condition. This relationship was not observed when nouns were produced, indicating a unique relationship between verb production and functional grasping. Theresult is a facilitation effect, diminishing the negative outcome on motor control associated with increased cognitive load (as observed during noun pronunciation).

Deep Learning Based Real-Time Recognition of Dynamic Finger Gestures Using a Data Glove

In this article, a real-time dynamic finger gesture recognition using a soft sensor embedded data glove is presented, which measures the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint angles of five fingers. In the gesture recognition field, a challenging problem is that of separating meaningful dynamic gestures from a continuous data stream. Unconscious hand motions or sudden tremors, which can easily lead to segmentation ambiguity, makes this problem difficult. Furthermore, the hand shapes and speeds of users differ when performing the same dynamic gesture, and even those made by one user often vary. To solve the problem of separating meaningful dynamic gestures, we propose a deep learning-based gesture spotting algorithm that detects the start/end of a gesture sequence in a continuous data stream. The gesture spotting algorithm takes window data and estimates a scalar value named gesture progress sequence (GPS). GPS is a quantity that represents gesture progress. Moreover, to solve the gesture variation problem, we propose a sequence simplification algorithm and a deep learning-based gesture recognition algorithm. The proposed three algorithms (gesture spotting algorithm, sequence simplification algorithm, and gesture recognition algorithm) are unified into the real-time gesture recognition system and the system was tested with 11 dynamic finger gestures in real-time. The proposed system took only 6 ms to estimate a GPS and no more than 12 ms to recognize the completed gesture in real-time.

Chemical, thermal and dilution effects of carbon dioxide in oxy-fuel combustion of wood in a fixed bed

Experimental and numerical modeling was performed on eucalyptus wood combustion under oxy-fuel conditions using a fixed bed reactor in order to isolate the role of various carbon dioxide effects on the burning rate. Wood combustion was investigated under four different mixtures of O2 and Ar/CO2/N2: 21 % O2/79 % N2; 21 % O2/22.5 % CO2/56.5 % Ar; 40 % O2/60 % CO2; and 40 % O2/47 % CO2/13 % Ar. The first three mixtures were designed to have the same peak temperatures in order to isolate chemical and dilution effects of CO2. This was achieved by substituting some percentage of CO2 with Ar in O2/CO2 mixture while maintaining a constant concentration of O2. The fourth mixture was meant to isolate the thermal effect of CO2. The results were obtained from both the experimental rig and numerical simulation for a fixed bed configuration. Wood combustion in the fixed bed was modeled using Lagrange-Euler method, where gas-phase was calculated using computational fluid dynamics (CFD), that is Euler phase, while solid-phase was tracked in Lagrange phase using discrete element method (DEM). The results show that ignition time in CO2 environment decreases gradually as O2 concentration is increased. On the other hand, burning rate and flame front speed increase as O2 concentration is increased. It was established that dilution effect is the most influential parameter on the burning rate of wood combustion in an oxy-fuel system.

Integrated robotics platform with haptic control differentiates subjects with Parkinson\u2019s disease from controls and quantifies the motor effects of levodopa

BackgroundThe use of integrated robotic technology to quantify the spectrum of motor symptoms of Parkinson’s Disease (PD) has the potential to facilitate objective assessment that is independent of clinical ratings. The purpose of this study is to use the KINARM exoskeleton robot to (1) differentiate subjects with PD from controls and (2) quantify the motor effects of dopamine replacement therapies (DRTs).MethodsTwenty-six subjects (Hoehn and Yahr mean 2.2; disease duration 0.5 to 15 years) were evaluated OFF (after > 12 h of their last dose) and ON their DRTs with the Unified Parkinson’s Disease Rating Scale (UPDRS) and the KINARM exoskeleton robot. Bilateral upper extremity bradykinesia, rigidity, and postural stability were quantified using a repetitive movement task to hit moving targets, a passive stretch task, and a torque unloading task, respectively. Performance was compared against healthy age-matched controls.ResultsMean hand speed was 41% slower and 25% fewer targets were hit in subjects with PD OFF medication than in controls. Receiver operating characteristic (ROC) area for hand speed was 0.94. The torque required to stop elbow movement during the passive stretch task was 34% lower in PD subjects versus controls and resulted in an ROC area of 0.91. The torque unloading task showed a maximum displacement that was 29% shorter than controls and had an ROC area of 0.71. Laterality indices for speed and end total torque were correlated to the most affected side. Hand speed laterality index had an ROC area of 0.80 against healthy controls. DRT administration resulted in a significant reduction in a cumulative score of parameter Z-scores (a measure of global performance compared to healthy controls) in subjects with clinically effective levodopa doses. The cumulative score was also correlated to UPDRS scores for the effect of DRT.ConclusionsRobotic assessment is able to objectively quantify parkinsonian symptoms of bradykinesia, rigidity and postural stability similar to the UPDRS. This integrated testing platform has the potential to aid clinicians in the management of PD and help assess the effects of novel therapies.

Effects of handwriting exercise on functional outcome in Parkinson disease: A randomized controlled trial

Parkinson disease (PD) patients frequently experience micrographia and difficulty writing, which could potentially impact their quality of life. This study aimed to determine whether handwriting exercise could improve fine manual motor function in PD. The study was a randomized controlled trial assessing the efficacy of a 4-week handwriting exercise using a newly developed handwriting practice book. The primary endpoint was an improvement in the time used to complete the handwriting test. Secondary endpoints were accuracy of the writing performance, patient’s subjective rating scale of their handwriting and a UPDRS part III motor examination. Of a total of 46 subjects, 23 were randomly assigned to the handwriting exercise group. After 4 weeks, the mean time used to complete the test was significantly lower in the exercise group, compared to the control group (143.43 ± 34.02 vs. 175 ± 48.88 s, p = 0.015). Mean time used to complete the handwriting test decreased from the baseline by 16.16% in the exercise group, but increased by 3.63% in the control group (p < 0.001). Significant improvements were also observed by assessing the subjective rating scale and the UPDRS part III scores. The 4-week handwriting exercise using the studied handwriting practice book appears to promote an improvement in writing speed and motor function of hands. The optimal duration and frequency of the exercise, the quantity and characteristic of the letters in the handwriting practice book, and the benefits of the exercise in other languages merit further studies.

Effect of handrail height and age on the timing and speed of reach-to-grasp balance reactions during slope descent

We investigated the effect of handrail height on the timing and speed of reach-to-grasp balance reactions during slope descent, in fourteen younger and thirteen older adults. Participants walked along an 8° slope mounted to a robotic platform. Platform perturbations evoked reach-to-grasp reactions. Handrail height did not significantly affect handrail contact time (i.e., time from perturbation onset to handrail contact) or movement time (i.e., time from EMG latency to handrail contact). Participants appeared to compensate for the increased hand-handrail distance with higher rails via increased peak upward hand speed, and decreased vertical handrail overshoot. Aging was associated with slower EMG latency, reduced hand acceleration time, and increased hand deceleration time. Our findings suggest that participants were not disadvantaged by higher handrails from reach-to-grasp timing or speed perspectives, and that other metrics (e.g., center-of-mass control after grasping) may be more important when evaluating handrail designs for balance recovery.

Audio cues enhance mirroring of arm motion when visual cues are scarce.

Swing in a crew boat, a good jazz riff, a fluid conversation: these tasks require extracting sensory information about how others flow in order to mimic and respond. To determine what factors influence coordination, we build an environment to manipulate incoming sensory information by combining virtual reality and motion capture. We study how people mirror the motion of a human avatar's arm as we occlude the avatar. We efficiently map the transition from successful mirroring to failure using Gaussian process regression. Then, we determine the change in behaviour when we introduce audio cues with a frequency proportional to the speed of the avatar's hand or train individuals with a practice session. Remarkably, audio cues extend the range of successful mirroring to regimes where visual information is sparse. Such cues could facilitate joint coordination when navigating visually occluded environments, improve reaction speed in human-computer interfaces or measure altered physiological states and disease.

Применение нестабильных опор и упражнений для контроля положения центра тяжести в тренировочном процессе баскетболисток 13-14 лет

Цель работы - экспериментально обосновать методику развития специальной физической и технической подготовленности баскетболисток 13-14 лет. Материал и методы. В эксперименте приняли участие баскетболистки ДЮСШ №13 (возраст 13-14 лет): экспериментальная группа (n=18); контрольная группа (n=18). Эксперимент проводился в августе 2018 года в течение трех месяцев. До и после эксперимента было проведено тестирование баскетболисток по физической подготовленности (бег 6 м, челночный бег 2х28 м, сгибание рук в упоре лежа, прыжки на скакалке), технической подготовленности (скорость защитных перемещений, броски с разной дистанции, скоростное ведение мяча). Для определения психофизиологического состояния спортсменок эксперимента регистрировали психофизиологические показатели с помощью компьютерной программы «Психодиагностика» (скорость простой и сложной реакции в различных режимах тестирования). Для определения скорости моторики рук использовался тест «Перекладывание фишек». Результаты. Разработана и внедрена в тренировочный процесс юных баскетболисток методика развития специальной физической и технической подготовленности баскетболисток. Методика включает в себя выполнение упражнений с помощью резиновой ленты, упражнения с использованием нестабильных платформ и бег из нестандартных исходных положений. Выявлено достоверное (р&lt;0,05) улучшение показателей в тестах: скорость защитных перемещений, челночный бег, скоростная техника ведения мяча, броски с разных дистанций спортсменок экспериментальной группы по сравнению с контрольной. Установлено достоверное (р&lt;0,05) различие показателей после проведения эксперимента в тестах: скорость простой и сложной реакции и моторики рук спортсменок экспериментальной группы по сравнению со спортсменками контрольной группы. Выводы. Показано положительное влияние экспериментальной методики на уровень физической, технической подготовленности и психофизиологическое состояние баскетболисток 13-14 лет.

Assessment of Cognitive and Motor Skills in Parkinson's Disease by a Robotic Object Hitting Game.

Parkinson's disease (PD) patients experience various symptoms including extrapyramidal motor disturbances and cognitive impairments, which cause difficulties in daily life. However, PD patients have rarely been studied under realistic task situations that require high-level interaction of cognitive and motor skills. The aim of this study was to investigate the contribution of cognitive and motor factors to the performance of PD patients under high cognitive and kinematic loads. Twenty-six PD patients and 14 control subjects participated in the study. The PD patients performed a task involving hitting targets and avoiding distractors in levodopa On and Off states. A robotic manipulandum device recorded the numbers of target and distractor hits and hand kinematics, including movement area and speed. Performance on standard cognitive batteries and the Movement Disorder Society – Unified Parkinson's Disease Rating Scale motor scores were examined. The results indicated that the PD patients hit significantly fewer targets and more distractors than did the controls (p < 0.05). In PD patients, the average hand speed was slower and the area of hand movement was smaller than those of the control subjects (p < 0.001). Levodopa significantly increased the average hand speed and movement area (p < 0.01), but levodopa had an insignificant effect on the number of correct targets hit and erroneous distractor hits. The scores of cognitive batteries predicted the performance with regard to both targets hit and distractor avoidance. Our results were indicative of a dynamic interaction between cognitive and kinematic skills while the PD patients performed a virtual reality game. Single-dose levodopa enhanced kinematic capacity, and the global intelligence level predicted game performance.

Virtual reality in upper extremity dysfunction: specific features of usage in acute stroke

Stroke is a leading cause of permanent disability. Being a new technology for neurorehabilitation, virtual reality (VR) allows for intensive trainings with a larger number of repetitions focused on mastering specific skills in patients with upper limb dysfunction. To date, there are insufficient studies evaluating the use of VR in the acute period of a stroke. To investigate the effectiveness and safety of adding VR trainings to standard therapy for improving upper limb function and for enhancing activities in daily life in patients with acute stroke. The investigation enrolled 78 patients with acute stroke (the median time from stroke onset, 3.7 days; median age, 63 (43; 79.3) years), who were randomized into 2 groups: a study group (standard therapy + VR) and a control one (standard therapy only). The patients of the study group underwent a VR training cycle lasting 15 minutes twice daily for 10 days. Before and after the training cycle, the British Medical Research Council scale for muscle strength, the upper extremity motor function sections of the Fugl-Meyer assessment (FMA) scale, hand dynamometry, and the nine hole peg test (NHPT) were used to evaluate upper extremity function in the participants; Sections 6 and 7 of the motor function assessment scale (MAS), the modified Rankin scale (MRS), and the total motor function scores of the functional independence measure (FIM) utilizing a 7-point ordinal scale were employed to assess everyday activity limitations. On completion of rehabilitation measures, the participants in the study and control groups showed a statistically significant improvement in upper extremity function and activities of daily living. According to the ratings of the FMA subscales 'hand' (p=0.034), 'hand (speed)' (p<0,001), and the total score of this scale (p=0.035) and according to those of the FIM scale (p=0.045), the patients of the study group demonstrated a statistically significant improvement compared with those in the control group. Assessments using the MRC scale, FMA subscales 'upper extremity' and 'wrist', NHPT, MAS, the Barthel index (BI), and MRS revealed no differences between the groups. No serious adverse events were recorded in the participants of the study group during the study period. The vast majority of studies evaluating the effect of VR in upper extremity dysfunction are conducted in patients with stroke lasting longer than 3 months. Despite the validity of using VR in the acute period of cerebral lesion, the investigations of this design are not numerous. At the same time, these studies often have limitations, such as a small number of participants (usually less than 10); a small number of training VR sessions; lack of 'blinding'; different types of software and hardware systems that implement VR technology; heterogeneity of participants according to the degree of upper extremity dysfunction; insufficient detailing of the content and scope of conventional therapy; comparison of VR with basic methods of motor rehabilitation, and sometimes the absence of a control group. Thus, the use of VR in addition to standard rehabilitation measures in the acute period of stroke favors improvements in upper extremity function and a reduction in daily limitations and is safe.

Single-Trial Recognition of Imagined Forces and Speeds of Hand Clenching Based on Brain Topography and Brain Network

To provide optional force and speed control parameters for brain–computer interfaces (BCIs), an effective feature extraction method of imagined force and speed of hand clenching based on electroencephalography (EEG) was explored. Twenty subjects were recruited to participate in the experiment. They were instructed to perform three different actual/imagined hand clenching force tasks (4 kg, 10 kg, and 16 kg) and three different hand clenching speed tasks (0.5 Hz, 1 Hz, and 2 Hz). Topographical maps parameters and brain network parameters of EEG were calculated as new features of imagined force and speed of hand clenching, which were classified by three classifiers: linear discrimination analysis, extreme learning machines and support vector machines. Topographical maps parameters were better for recognition of the hand clenching force task, while brain network parameters were better for recognition of the hand clenching speed task. After a combination of five types of features (energy, power spectrum of the autoregressive model, wavelet packet coefficients, topographical maps parameters and brain network parameters), the recognition rate of the hand clenching force task was 97%, and that of the hand clenching speed task was as high as 100%. The brain topographical and the brain network parameters are expected to improve the accuracy of decoding the EEG signal of imagined force and speed of hand clenching. A more efficient brain network may facilitate the recognition of force/speed of hand clenching. Combined features could significantly improve the single-trial recognition rate of imagined forces and speeds of hand clenching. The current study provides a new idea for the imagined force and speed of hand clenching that offers more control intention instructions for BCIs.

Regenerative peripheral nerve interfaces for real-time, proportional control of a Neuroprosthetic hand

IntroductionRegenerative peripheral nerve interfaces (RPNIs) are biological constructs which amplify neural signals and have shown long-term stability in rat models. Real-time control of a neuroprosthesis in rat models has not yet been demonstrated. The purpose of this study was to: a) design and validate a system for translating electromyography (EMG) signals from an RPNI in a rat model into real-time control of a neuroprosthetic hand, and; b) use the system to demonstrate RPNI proportional neuroprosthesis control.MethodsAnimals were randomly assigned to three experimental groups: (1) Control; (2) Denervated, and; (3) RPNI. In the RPNI group, the extensor digitorum longus (EDL) muscle was dissected free, denervated, transferred to the lateral thigh and neurotized with the residual end of the transected common peroneal nerve. Rats received tactile stimuli to the hind-limb via monofilaments, and electrodes were used to record EMG. Signals were filtered, rectified and integrated using a moving sample window. Processed EMG signals (iEMG) from RPNIs were validated against Control and Denervated group outputs.ResultsVoluntary reflexive rat movements produced signaling that activated the prosthesis in both the Control and RPNI groups, but produced no activation in the Denervated group. Signal-to-Noise ratio between hind-limb movement and resting iEMG was 3.55 for Controls and 3.81 for RPNIs. Both Control and RPNI groups exhibited a logarithmic iEMG increase with increased monofilament pressure, allowing graded prosthetic hand speed control (R2 = 0.758 and R2 = 0.802, respectively).ConclusionEMG signals were successfully acquired from RPNIs and translated into real-time neuroprosthetic control. Signal contamination from muscles adjacent to the RPNI was minimal. RPNI constructs provided reliable proportional prosthetic hand control.

MENINGKATKAN KREATIVITAS MELALUI METODE PEMBERIAN TUGAS MELIPAT KERTAS PADA SISWA KELOMPOK B TK ISLAM YLPI MARPOYAN PEKANBARU

Kindergarten is an educational institution intended for children aged 4–6 years to carry out a learning process so children can develop their potential early on. Children must obtain their motor, intellectual, social and emotional stimuli according to their age level. From an early age, children are introduced to folding paper. In kindergarten learning, most teachers pay less attention to children's learning outcomes towards this one learning. Teachers often use paper folding as a relaxation learning for children who pay less attention to children's learning outcomes towards this one learning. Teachers often use paper folding as a relaxation study for children regardless of the results of children's work so that it is found that children's work in learning to fold paper seems without direction. The purpose of this study was to find out that folding paper can increase children's creativity in the B3 Group of Islamic Kindergarten YLPI Marpoyan, Pekanbaru. This study is a Classroom Action Research (CAR) conducted in two cycles, in each cycle of three meetings. The results showed that the paper folding development activities in the B3 group with the assignment of tasks had succeeded and increased. Increasing children's creativity through paper folding activities can be seen in cycle II. Hand speed coordination with the eye in carrying out the activities between the hand and eye are interconnected, careful, concentration on the tasks of activities carried out by students at the time of the activity activities hope that the resulting work is better, neater and faster in completing.

Experimental Studying of the Variations of Surface Roughness and Dimensional Accuracy in Dry Hard Turning Operation

Objective: Hard turning in dry condition using cubic boron nitride tools, as an alternative of traditional grinding operation, is an advanced machining operation in which hardened steel with the hardness greater than 46 HRc is machined without the use of any coolant. Method: In the hard turning process, due to its hard nature, usually the cutting depth is selected lower than or equal to the nose radius, and the cutting zone is mainly limited within the tool nose area. Thus, unlike the traditional turning, the effect of the nose radius on the surface finish and dimensional accuracy becomes more complicated. Therefore, in this paper, firstly, the effect of processing parameters such as nose radius on the surface roughness and dimensional accuracy is investigated. Then, the relationship between the surface finish and dimensional accuracy variations with vibration, cutting forces, and tool wear is studied experimentally. The results revealed that feed rate is the most important factor influencing the surface roughness, whereas spindle speed and cutting depth are insignificant factors. On the other hand, cutting depth and spindle speed have the greatest effect on the dimensional accuracy, while nose radius has no significant effect. The vibration and wear analysis revealed that compared with the vibration, the tool wear has no considerable effect on the dimensional accuracy. It was also observed that the spindle speed has a contradictory effect on the surface roughness and dimensional accuracy. The best dimensional accuracy is obtained at 500 rpm, while the best surface quality is achieved at 2000 rpm. Result: The obtained results also showed that increasing the feed rate from a particular value not only leads to no significant changes in the surface roughness value but in some cases can also decrease the surface roughness. Conclusion: According to the analysis results, the lowest cutting depth, the moderate feed rate, and the speed lower than 1100 rpm provide the best dimensional accuracy. Compared with carbides and ceramics, cubic boron nitride tools produce a better surface roughness at both higher cutting depth and speed. 0.202 µm is the best surface roughness that was obtained at rε = 1.2 mm, N = 2000 rpm, f = 0.08 mm/rev, d = 0.5 mm which is comparable with the surface quality obtained by the conventional grinding operation.

How Do Computer Vision Upper Extremity Exposure Measures Compare Against Manual Measures?

Background Various quantification methods have been used to measure exposure to risk factors for musculoskeletal injuries, including observation, video-based frame-by-frame analysis, and direct measurements. Each technique has advantages and disadvantages. The American Conference of Government Industrial Hygienists (2017) Threshold Limit Value® (TLV®) uses the hand activity level (HAL) rating scale, a 10-point visual analog scale based on hand speed and rest pauses. HAL may be determined subjectively by an observer or from a lookup table, or an equation by measuring exertion frequency ( F) and percent duty cycle ( D). This study compares task level physical exposure variables measured manually and using video computer vision for jobs selected from a selected subset of the Upper Limb MSD Consortium prospective study. We compared F and D, calculated both using manual single-frame MVTA analysis and automatic computer vision (Akkas et al., 2015, Akkas et al., 2016, Akkas et al., 2017, Greene et al., 2017). Methods This study utilized exposure data from prospective studies conducted by the National Institute for Occupational Safety and Health (NIOSH), the Safety &amp; Health Assessment &amp; Research for Prevention (SHARP) in the State of Washington, and the University of California -San Francisco (UCSF). Some data from these prospective cohort studies had been previously pooled and analyzed as part of the Upper Limb MSD Consortium, a group of seven prospective cohort studies (Bao et al., 2015; Harris-Adamson et. al., 2013a, 2013b; Harris-Adamson et. al., 2014; Kapellusch et al., 2013, 2014; Fan et al., 2015). Because the videos were created for a different purpose, not all were suitable for computer vision analysis. We selected 1001 videos where we applied hand tracking and data checking to date. Thus, not all study sites are equally represented. The occurrence of each exertion was first identified in all the videos by human analysts for manually calculating the frequency (exertions/ second) and duty cycle (percent exertion time/ cycle time). The hands were tracked using marker-less video tracking and a feature vector training (FVT) algorithm (Akkas et al., 2016 Akkas et al., 2017) was trained using the first cycle exertions identified by an analyst, for automatically estimating subsequent exertions in the videos. We then applied the FVT algorithm to the 1001 videos clips and automatically identified video frames representing exertions of the dominant hand. As a result, we counted total frames of exertions as well as the total number of exertions to calculate F and D. Results The calculated D (%) and F (Hz) errors were the average difference between the manual frame-by-frame and the computer vision estimates. We found an average error of 12.7% (SD=36.8%) for D and 0.06 Hz (SD=0.38 Hz) for F. The average HAL error was 1.3 (SD=2.2), which is considered negligible. Conclusions The results indicate that computer vision can reliably estimate important exposure variables for many tasks. Since the videos used in this study were taken for a different purpose, we anticipate the algorithms will perform better when videos are recorded specifically for computer vision analysis.

Towards a classification of surgical skills using affine velocity

The aim of this study is to determine if navigation movements, used in surgical training, follow a particular power law which describes the relationship between the hand trajectory's curvature, torsion, and speed. Based on this approach, this study proposes the affine velocity as an appropriate classification feature to solve the surgical movement recognition problem. Eight subjects with different surgical experience were involved in the experiments. They were asked to do two kinds of movements that involve depth perception skills with their right arm. Using six video cameras and an instrumented laparoscope, the 3D trajectory of the end effector was recorded for each participant. A power law was used to fit the data sets and the exponents that relate the torsion, curvature, and speed were calculated. The exponents involved and the affine velocity for each trajectory were then computed, using a multi-variable linear regression, and compared between participants. It is shown that fitting residual follows a normal distribution indicating no regression biases. Finally, it is presented that an affine velocity analysis could be able to classify between both trajectories showing a correlation with the surgical skills and a clear difference for people with some surgical training.

Early estimation model for 3D-discrete indian sign language recognition using graph matching

Machine translation of sign language is a critical task of computer vision. In this work, we propose to use 3D motion capture technology for sign capture and graph matching for sign recognition. Two problems related to 3D sign matching are addressed in this work: (1) how to identify same signs with different number of motion frames and (2) sign extraction from a clutter of non-sign hand motions. These two problems make the 2D or 3D sign language machine translation a challenging task. We propose graph matching with early estimation model to address these problems in two phases. The first phase consists of intra graph matching for motion frame extraction, which retains motion intensive frames in database and query 3D videos. The second phase applies inter graph matching with early estimation model on motion extracted query and dataset 3D videos. The proposed model increases the speed of the graph matching algorithm in estimating a sign with fewer frames. To test the graph matching model, we recorded 350 words of Indian sign language with 3D motion capture technology. For testing 4 variations per sign are captured for all signs with 5 different signers at same, slower, faster hand speeds and sign mixed cluttered hand motions. The early estimation graph matching model is tested for accuracy and efficiency in classifying 3D signs with the two induced real time constraints. In addition to 3D sign language dataset, the proposed method is validated on five benchmark datasets and against the state-of-the-art graph matching methods.

Evaluating the OSHA hand speed constant for stamping press applications

Occupational Safety and Health Administration (OSHA) utilizes ‘hand speed’ as a critical machine guarding parameter. OSHA’s current hand speed constant is based upon research conducted by Löbl (1935), who used a fixed hand starting position to estimate the maximum human hand speed of five males at 1.6 m/s (63 in./s). Sixty (60) college students participated in the present study to ascertain a more accurate estimate of the 95th percentile hand speed for machine guarding applications. Results indicated that the hand speed between the upper and lower dual palm button positions are significantly different, and for the upper button location OSHA’s hand speed constant may not be conservative enough to protect some operators. Specifically, the 95th percentile hand speed from the lower button was 1.510 m/s (protective for >95% of those tested), but the 95th percentile hand speed from the upper buttons was 2.825 m/s (protective < 10% of those tested). These results suggest that control location with respect to the point-of-operation should be considered since hand speed is significantly impacted by relative position.