• Journal of Korea Society of Industrial Information Systems
• /
• v.10 no.4
• /
• pp.54-64
• /
• 2005

The study investigated genetic algorithms for the optimal control model of maximum height vertical jumping. The model includes forward dynamic simulations by the neural excitation-control variables. Convergence of genetic algorithms is very slow. In this paper the micro genetic algorithm(micro-GA) was used to reduce the computation time. Then a near optimal solution from micro-GA was an initial solution for VF02, which is one of well-developed and proven nonlinear programming algorithms. This approach provided the successful optimal solution for maximum-height jumping without a reasonable initial guess.

• Journal of Biomedical Engineering Research
• /
• v.26 no.2
• /
• pp.101-110
• /
• 2005

Periosteum and periosteum-derived progenitor cells have demonstrated the potential for stimulative applications in repairs of various musculoskeletal tissues. It has been found that the periosteum contains mesenchymal progenitor cells capable of differentiating into either osteoblasts or chondrocytes depending on the culture conditions. Anatomically, the periosteum is a heterogeneous multi-layered membrane, consisting of an inner cambium and an outer fibrous layer. The present study was designed to elucidate the cellular phenotypic characteristics of cambium and fibrous layer cells in vitro, and to assess whether structural integrity of the tendon in the bone tunnel can be improved by periosteal augmentation of the tendon­bone interface. It was found the cells from each layer showed distinct phenotypic characteristics in a primary monolayer culture system. Specifically, the cambium cells demonstrated higher osteogenic characteristics (higher alkaline phosphatase and osteocalcin levels), as compared to the fibrous cells. Also in vivo animal model showed that a periosteal augmentation of a tendon graft could enhance the structural integrity of the tendon-bone interface, when the periosteum is placed between the tendon and bone interface with the cambium layer facing toward the bone. These findings suggest that extra care needs to be taken in order to identify and maintain the intrinsic phenotypes of the heterogeneous cell types within the periosteum. This will improve our understanding of periosteum in applications for musculoskeletal tissue repairs and tissue engineering.

• Journal of the Korean Society of Safety
• /
• v.21 no.4 s.76
• /
• pp.114-118
• /
• 2006

Recently, work-related musculoskeletal disorders(WMSDs) is one of the major issues in the shipbuilding industry. The number of injured workers has rapidly increased and demands for workers compensation, improvement of work condition and environment to prevent WMSDs become larger. To protect and reduce WMSDs in the shipbuilding industry, simulation technique which showed it's ability of increasing the manufacturing productivity will be applied, because simulation technique has the evaluation ability for a worker's danger level of production process by human activity analysis. In our research, we modeled worker's attitude and simulated worker's action. We evaluated the caution level, compared and analyzed the difference point of digital human which made on computer and actual worker's attitude to check feasibility of human modeling and simulation in the shipbuilding industry.

• Journal of The Korean Society of Integrative Medicine
• /
• v.4 no.4
• /
• pp.83-90
• /
• 2016

Purpose : Recommended posture according to the location of operating teeth have been standardized in dental clinic to prevent musculoskeletal disorder. However, clinicians do not comply with this rule in many cases. This study investigated the effects of operating posture on cranio-cervical range of motion (CROM) and muscles activity of neck and upper extremity. Methods : Sixteen healthy dental hygiene students were participated. During operating posture (3 recommended and 3 experimental postures which were set front, side, back, respectively), CROM in the fronal and sagittal plane were measured by Cervical Range of Motion Instrument and muscle activities of Sternocleidomastoid, upper trapezius, middle deltoid, extensor carpi radialis, brachioradialis, and abductor pollicis brevis were measured by Pocket EMG system. Result : CROM were significantly decreased in recommended posture in comparison with experimental posture (p<.05). In addition, muscle activity of middle deltoid was significantly decreased in recommended front posture. Moreover, brachioradialis and extensor carpi radialis showed the same result in recommended back posture (p<.05). Conclusion : Recommended posture is close to neutral posture and to reduce muscle fatigue and overuse, which may considered as a preventing musculoskeletal disorder and partially explain its efficacy in dental clinic.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.24 no.67
• /
• pp.1-10
• /
• 2001

A series of studies with collaboration of university, research institute, and labor union were conducted to examine the situation and severity of work-related musculoskeletal disorders (MSDs) at an automobile company which is one of the three major car companies in Korea. As the first part of the study, a questionnaire survey was conducted on 4,000 employees at 2 different assembly sites and A/S centers over the country. The questionnaire was consisted of three parts; symptom survey, work environment information, and labor intensity survey. Among 4,000 questionnaires, 2,643 responses were considered for analysis. The result showed that 68.5% of the respondents complained pains on at least one part of the body and 48.8% on at least two parts of the body. After cross-sectional analysis of various information and risk factors such as severity of symptom, duration and frequency of pain, 31.5% of respondents were considered as at high risk of having MSDs. This high-risk rate showed similar result when compared with previous studies conducted at various manufacturing industries in Korea. Also the analysis of the work environment and job intensity survey supported the high-risk rate of MSDs.

• Journal of the Korea Safety Management & Science
• /
• v.14 no.4
• /
• pp.59-70
• /
• 2012

This study compared data regarding industrial accidents and awareness level for beauty product safety for four main parts of beauty industry such as hair-care, nail-care, skin-care, and make-up. Major risk factors in beauty industry are dust, musculoskeletal disorders, and organic solvent of beauty product in order of percentage. The specific types of industrial accidents in beauty industry are mainly associated with musculoskeletal system such as cuts, sprain, and varicose vein. They are mainly compensated by personal budget. The awareness levels of chemical and heavy metal containment for beauty product by beauty industry employee were 77.2% and 59.1% respectively. Most employee confirmed only important items of labelling requirement of beauty product. Also, most employee did not understand MSDS(Materila Safety Data) for chemicals used in beauty industry. Only 38.1% of beauty industry employee has had safety education while most employee (73.6%) realized that they needed safety education. Also, safety education supervised by KOSHA(Korea Occupational Safety and Health Agency) was the most preferred. This study would be good basis for safe and healthy working environment of beauty industry employee.

• Journal of the Korea Safety Management & Science
• /
• v.22 no.2
• /
• pp.31-38
• /
• 2020

The study evaluated the accuracy and intra-rater reliability for OWAS (Ovako Working posture Analysing System), RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment) to improve their evaluation accuracy and reliability. Participants (n = 163) with undergraduate degree were recruited in this study and trained for 6 hours about the ergonomic assessment methods. Ergonomic assessments were conducted using OWAS, RULA, and REBA for a representative work with dynamic posture found in manufacturing industries. The study compared action categories (overall level) and detailed evaluation scores for individual body part. Action categories of the participants significantly differed from the golden reference defined by ergonomic experts. The participants underrated or omitted scores for truck (37.4% of the participants) and legs (52.8%) in OWAS. Similarly, the participants underrated or omitted additional scores for all body parts except the hand and wrist in RULA (53.5%) and REBA (54.8%). On the other hand, the participants overrated scores for the hand and wrist in RULA (55.2%) and REBA (39.9%). The results found in this study can help of selecting focus points and parts during assessment and education to improve accuracy and reliability of the ergonomic assessment methods.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.728-735
• /
• 2022

Roofers get exposed to increased risk of knee musculoskeletal disorders (MSDs) at different phases of a sloped shingle installation task. As different phases are associated with different risk levels, this study explored the application of machine learning for automated classification of seven phases in a shingle installation task using knee kinematics and roof slope information. An optical motion capture system was used to collect knee kinematics data from nine subjects who mimicked shingle installation on a slope-adjustable wooden platform. Four features were used in building a phase classification model. They were three knee joint rotation angles (i.e., flexion, abduction-adduction, and internal-external rotation) of the subjects, and the roof slope at which they operated. Three ensemble machine learning algorithms (i.e., random forests, decision trees, and k-nearest neighbors) were used for training and prediction. The simulations indicate that the k-nearest neighbor classifier provided the best performance, with an overall accuracy of 92.62%, demonstrating the considerable potential of machine learning methods in detecting shingle installation phases from workers knee joint rotation and roof slope information. This knowledge, with further investigation, may facilitate knee MSD risk identification among roofers and intervention development.

• Physical Therapy Korea
• /
• v.23 no.1
• /
• pp.87-93
• /
• 2016

Background: Posture balance control is the ability to maintain the body's center of gravity in the minimal postural sway state on a supportive surface. This ability is obtained through a complicated process of sensing the movements of the human body through sensory organs and then integrating the information into the central nervous system and reacting to the musculoskeletal system and the support action of the musculoskeletal system. Motor function, including coordination, motor, and vision, vestibular sense, and sensory function, including proprioception, should act in an integrated way. However, more than half of stroke patients have motor, sensory, cognitive, and emotional disorders for a long time. Motor and sensory disorders cause the greatest difficulty in postural control among stroke patients. Objects: The purpose of this study is to determine the effect of visual and somatosensory information on postural sway in stroke patients and carrying out a kinematic analysis using a tri-axial accelerometer and a quantitative assessment. Methods: Thirty-four subjects posed four stance condition was accepted various sensory information for counterbalance. This experiment referred to the computerized dynamic posturography assessments and was redesigned four condition blocking visual and somatosensory information. To measure the postural sway of the subjects' trunk, a wireless tri-axial accelerometer was used by signal vector magnitude value. Ony-way measure analysis of variance was performed among four condition. Results: There were significant differences when somatosensory information input blocked (p<.05). Conclusion: The sensory significantly affecting the balance ability of stroke patients is somatosensory, and the amount of actual movement of the trunk could be objectively compared and analyzed through quantitative figures using a tri-axial accelerometer for balance ability.

• Journal of Haehwa Medicine
• /
• v.14 no.2
• /
• pp.93-105
• /
• 2005

Objective : We investigated the actual condition of oriental medical office in a public health center. Methods : We classified patients who visited an oriental medical office iin a public pealth center of Dalseong-gun, Daegu Metropolitan City during recent 3 years by KCPJMAIN(data processing system), according to location, age, time(month, year), sex, disease, insurance, etc. Results : As a local category, the residents in Hyeunpung-Myeon higher than 80% of the patients who visited the public health center. The patients aged over 60 occupied 80% of the patients. The frequency of the treatment was more than 10 in those patients aged over 60. The number of the patients was the highest in May when there was a change for the past 36months, whereafter the number has sustained decline for 3-5 months and repeated decreasing. As a gender category, the female inpatients were 10732(82%). This statistics shows that these musculoskeletal system disease occupied large part in them. As a heath insurance category, the patients who were insured by health care were 12454(96.30%). Conclusion : It should need to enable the rural residents who have difficulty benefitting from medical service to reach the service by making their access to the oriental medical office in public health center easier. Most of all, the support from both government and municipality should be urged to accomplish it. plus, it should be included not only boosting doctors' reliance but also improving the capability and services of doctors in public heath center. In conclusion, the treatment service in public health center should be diversified beyond musculoskeletal system disease and the identity transform of public health center should be needed to appeal to young generation.