Yun-Ju Lee

National Tsing Hua University | NTHU · Department of Industrial Engineering and Engineering Management

The accuracy of gait sensing detection and identification determines the usability and acceptability in field applications. Four inertial measurement units (IMUs) recorded from heel contact to toe-off as a footstep in gait. The 1400 footsteps from 70 participants were collected, and the 13 footsteps from each were randomly selected for the Siamese...

Virtual try-on technology (VTO) in virtual reality (VR) and augmented reality (AR) has been developed for years to create novel shopping experiences for users by allowing them to virtually wear fashion products. Compared to garments or facial accessories, fewer studies have focused on virtual footwear try-on, regardless of user study or technical d...

Background: Muscle fatigue of the lower limbs results in dynamic imbalance and gait instability, increasing the risk of falling. However, people might slow walk without physical muscle fatigue due to mental fatigue. Wearable inertial measurement units (IMU) and machine learning approaches have been well employed for recognizing human activities....

Smart manufacturing supported by emerging Industry 4.0 technologies is a key driver to realize mass product customizations. Augmented reality (AR) has been commonly applied to facilitate manual operations with ambient intelligence by overlaying virtual information on physical scenes. In most modern factories, maintenance remains an indispensable pr...

The objective is to develop a system to automatically select the corresponding assessment scales and calculate the score of the risk based on the joint angle information obtained from the imaged process (OpenPose) via image-based motion capture technology. Current occupational assessments, for example, REBA, RULA, and OWAS were used to evaluate the...

Maintenance of technical equipment in manufacturing is inevitable for sustained productivity with minimal downtimes. Elimination of unscheduled interruptions as well as real-time monitoring of equipment health can potentially benefit from adopting augmented reality (AR) technology. How best to employ this technology in maintenance demands a fundame...

Gait biometrics has grown sharply within decades and becomes an alternative approach for personal identification. However, the challenges of this application are difficult to record sufficient bioinformatics in gait for pattern recognition. Therefore, the study aimed to practically utilize the few features and steps for age and gender recognition....

In recent decade, pedelec has become one of the most popular transportation modes due to its effectiveness in reducing physical effort. The effects of using pedelec as an alternative mode of exercise were explored in previous studies. However, the effects of pedelec parameters were not quantified for the self-selected gear ratio, random riding spee...

The purpose of this study was to employ inertial measurement units (IMU) with an eye-tracking device to investigate different swing strategies between two levels of batters. The participants were 20 healthy males aged 20 to 30 years old, with ten professional and ten amateur batters. Eye gaze position, head, shoulder, trunk, and pelvis angular velo...

Background Stroke survivors suffer from hemiparesis and somatosensory impairments, which adversely impact walking performance, placing them at higher risks for trips and falls. Post-stroke, somatosensory deficits are commonly observed as impaired interpretation of afferent input and increased threshold. Diminishing or augmenting somatosensory input...

Post-stroke rehabilitation often aims to increase walking speeds, as faster walking is associated with improved functional status and quality of life. However, for successful community ambulation, ability to modulate (increase and decrease) walking speeds is more important than walking continuously at constant speeds. Increasing paretic propulsive...

Center of pressure (COP) during a gait cycle indicates crucial information with regard to fall risk such as balance capacity. The drawbacks of conventional research instruments include inconvenient use during activities of daily living and expensive costs. The present study illustrates the promising fall-relevant information predicted by accelerati...

Sound and sound frequency could improve postural sway in the elderly. The power spectrum intervals of the center of pressure (COP) displacement are associated with different postural regulations, which could be revealed by frequency analysis. The aim of the study was to investigate the effects of sound on dual-tasking postural control and conduct f...

Postural stability is commonly decreased in individuals with chronic post-stroke hemiparesis due to multisystemic deficits. Transcranial direct current stimulation (tDCS) is a non-invasive method to modulate cortical excitability, inducing neuroplastic changes to the targeted cortical areas and has been suggested to potentially improve motor functi...

Objective: Utilization of inertial measurement units (IMU) data for ground reaction force (GRF) prediction has been widely studied and documented when these sensors attach to the body segments. However, it was inconvenient and required people’s cooperation. A novel approach of the current study was setting IMU sensors mounted underneath the walking...

Background: Center of pressure (COP) trajectory during treadmill walking have been commonly presented using the butterfly diagram to describe gait characteristics in neurologically intact and impaired individuals. However, due to the large amount of displayed information, the butterfly diagram is not an efficient solution to visualize locomotor va...

Static standing postural stability has been measured by multiscale entropy (MSE), which is used to measure complexity. In this study, we used the average entropy (AE) to measure the static standing postural stability, as AE is a good measure of disorder. The center of pressure (COP) trajectories were collected from 11 subjects under four kinds of b...

Controllability of posture in the medial-lateral direction is critical for balance maintenance, particularly in step initiation. The objective of the current study was to examine the effects of external perturbation and landing orientation on medial-lateral control stability in step initiation. Eleven young healthy participants stood on the force p...

Static standing postural stability has been measured by multiscale entropy (MSE), which is used to measure complexity. In this study, we used the average entropy (AE) to measure the static standing postural stability, as AE is a good measure of disorder. The center of pressure (COP) trajectories were collected from 11 subjects under four kinds of b...

The purpose of the current study was to evaluate postural muscle performance of older adults in response to a combination of two motor tasks perturbations. Fifteen older participants were instructed to perform a pushing task as an upper limb perturbation while standing on a fixed or sliding board as a lower limb perturbation. Postural responses wer...

Background and Purpose Short term adaptations in the Ia afferent-motoneuron pathway, as measured using the H-reflex, in response to altered ground reaction forces (GRFs) applied at the feet during slope walking have been observed in the non-impaired nervous system. The ability of the stroke-impaired nervous system to adapt to altered GRFs have not...

Pushing is considered a manual handling activity in industry and its functional role is also in our daily life, such as pushing moving strollers or grocery carts, which is under examined. In such situations, two perturbations need to be handled simultaneously, specifically, pushing (voluntary movement) and pushing-induced slipping when walking on a...

Background: Gait initiation is associated with changes in the steady state and experiencing an external perturbation during initiation of gait could further threaten balance stability. Research question: The aim of the study was to investigate if changes in the symmetry of the perturbations affect patterns of muscle activity during gait initiati...

Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that indu...

Postural control is compromised in the presence of body instability. We studied anticipatory and compensatory postural adjustments people use to maintain balance while standing on an unstable surface and performing voluntary arm movements. Nine healthy participants stood on a sliding board (that was either locked and as such motionless or unlocked...

The role of point of application of perturbation in the anticipatory (APAs) and compensatory (CPAs) postural control was studied. Twelve healthy participants stood on a sliding board (that was either locked and as such motionless or unlocked and as such free to move in the anterior–posterior direction). The body perturbations were applied either to...

Background. To maintain standing balance, the central nervous system (CNS) employs anticipatory (APAs) and compensatory (CPAs) postural adjustments. Postural control is compromised in the presence of body instability. We studied APAs and CPAs that people use to maintain balance while standing on a stable and unstable surface and performing voluntar...

Standing on wedges changes the position in the ankle joints and affects postural stability in the medial-lateral direction. The objective of the study was to investigate the role of wedges and external lateral perturbations on anticipatory (APA) and compensatory postural adjustments (CPA). Ten healthy young participants were exposed to perturbation...

We investigated motor control perspectives of coordinating maintenance of posture and application of grip force when holding an object and being perturbed. Ten subjects stood on the force platform holding an instrumented object in their dominant hand and were exposed to an external perturbation applied to their shoulders. Task demands were manipula...

Asymmetry of standing balance and gait are common in individuals with neurological or musculoskeletal disorders and achieving symmetrical stance and gait is an important goal of rehabilitation. The aim of the study was to investigate if asymmetry of stance and gait observed immediately after the start of using a single textured insole remains durin...

Humans frequently assume asymmetrical postures while walking or standing in a crowded space with an object in one hand (a cellphone or a cup of coffee) and experience a body perturbation. Understanding the role of such a body asymmetry in the presence of the body perturbation is important for the optimization of the postural control. 10 young healt...

The ability to maintain balance deteriorates with increasing age. The aim was to investigate the role of age in generation of anticipatory (APA) and compensatory (CPA) postural adjustments during pushing an object. Older (68.8 ± 1.0. years) and young adults (30.1 ± 1.4. years) participated in the experiment involving pushing an object (a pendulum a...

The effect of body asymmetry on anticipatory and compensatory postural adjustments was studied. Ten healthy subjects stood on the force platform and held an object in one hand which induced body asymmetry. Subjects were exposed to external perturbations applied to their shoulders while standing with either normal or narrow base of support. Bilatera...

It is common to experience a body perturbation while standing or walking in a crowded space with an object in one hand. Ten healthy individuals stood on the force platform and held an object in the right (target) hand. They were exposed to external perturbations applied to their shoulders while standing with either normal or narrow base of support...

Deficit in balance control is a common and often an initial disabling symptom of multiple sclerosis (MS). The aim of the study was to investigate the organization of anticipatory and compensatory postural adjustments in individuals with MS dealing with external perturbations. Ten individuals with MS and ten age-and-gender matched healthy controls w...

The aim of the study was to investigate the role of short-term training in improvement of anticipatory postural adjustments (APAs) and its effect on subsequent control of posture in older adults. Nine healthy older adults were exposed to self-initiated and predictable external perturbations before and after a single training session consisting of t...

The use of a footrest while performing activity in standing is frequently associated with improvement of a user's well-being however no information exists on the role of a footrest in improving postural stability. The aim of the study was to evaluate the effects of using a footrest in postural control. Twenty healthy young volunteers were tested us...

The aim of this study was to evaluate the effects of muscle fatigue of triceps surae and quadriceps muscles in stepping down in ongoing gait. We expected that the subjects would compensate for muscle fatigue to prevent potential loss of balance in stepping down. A total of 10 young participants walked over a walkway at a self-selected velocity to s...

The objective of this study was to evaluate the effects of lateral and medial wedges on postural sway. Twenty healthy volunteers (mean age range of 28.45±3.34) participated in the study. They stood barefoot with eyes open or closed on each of the three surfaces: 10° lateral wedges, 10° medial wedges, and no wedges. Force platform data were collecte...

The ability to control balance is often compromised in people with multiple sclerosis (MS) and is considered to be a strong contributing factor towards their increased risk of falls. New Method: The aim of the study was to demonstrate that frequency analysis of postural sway could be used to investigate postural control in people with multiple scle...

To investigate effects of symmetric and asymmetric stance and pushing movement on anticipatory and compensatory postural adjustments (APAs and CPAs). Ten healthy volunteers stood symmetrically (feet parallel) or asymmetrically (one foot forward and the other backward) and pushed a handle with both hands or right or left hand. Bilateral EMG activity...

The stride before landing may be important during stepping down. The aim of this study was to analyze variability of the kinematics and muscle activity in the final stride before stepping down a curb, with and without ankle and knee muscle fatigue. Ten young participants walked at self-selected speed and stepped down a height difference (10-cm) in...

Objectives: Pushing tasks are functional activities of daily living. However, shoulder complaints exist among workers exposed to regular pushing conditions. It is crucial to investigate the control of shoulder girdles during pushing tasks. The objective of the study was to demonstrate scapular muscle activities and motions on the dominant side dur...

A number of occupational and leisure activities that involve pushing are performed in symmetrical or asymmetrical stance. The goal of this study was to investigate early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs) during pushing performed while standing. Ten healthy volunteers...

Deficit in balance control is a common and often an initial disabling symptom of multiple sclerosis (MS). The purpose of this study was to investigate if a light finger touch contact with a stationary surface is effective in improving upright postural stability in MS. Eleven individuals with relapsing-remitting MS were standing on a force platform...

Unlabelled: Information concerning the association of serum UA levels and the development of MS in the Chinese aging population is limited. The aims of this study were to investigate age-related metabolic disorders and analyze the relationship between serum UA levels and the components of MS in the elderly. This cross-sectional observational study...

Before altering the travel direction in normal gait, anticipatory activation in trunk muscles is observed, followed by a top-down sequence of rotation of body segments. Turning while pushing a cart is a more challenging task for the trunk because of its low stiffness in pushing while walking and the interaction with the high inertia of the cart. 12...

Unexpected sudden (un)loading of the trunk may induce inadequate responses of trunk muscles and uncontrolled trunk motion. These unexpected perturbations may occur in pushing tasks, when the cart suddenly starts moving (unloading) or is blocked by an obstacle (loading). In pushing, handle height affects the user's working posture, which may influen...

As unexpected sudden unloading of the trunk may cause low-back injury, the objective of the present study was to investigate whether handle height and the expectation of cart movement in pushing affect trunk control at movement onset. Eleven healthy male participants pushed a 200-kg cart with handles at shoulder and hip heights. The cart would sudd...

External perturbations during pushing tasks have been suggested to be a risk factor for low-back symptoms. An experiment was designed to investigate whether self-induced and externally induced sudden stops while pushing a high inertia cart influence trunk motions, and how flexor and extensor muscles counteract these perturbations. Twelve healthy ma...

Metabolic syndrome (MetS) and hyperuricemia are important risk factors for cardiovascular disease. However, findings regarding the relationship between serum uric acid (UA) level and components of MetS have been inconsistent. This study was performed to explore the potential value of UA level as a marker of MetS among male and female Chinese of dif...

Cyclic activation of the external and internal oblique muscles contributes to twisting moments during normal gait. During pushing while walking, it is not well understood how these muscles respond to presence of predictable (cyclic push-off forces) and unpredictable (external) perturbations that occur in pushing tasks. We hypothesized that the pred...