• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.152-162
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• 2024

Objective: This study was conducted to analyze the effect of wearable Electromyography-controlled functional electrical stimulation (EMG-controlled FES) System on Gait Function and cardiopulmonary metabolic efficiency during walking in older adults. Design: Cross-section study Methods: Total 22 older adult participants suitable to selection criteria of this study participated in this study. The EMG-controlled FES System, which functions as a wearable physical activity assist FES system was used. All participations performed randomly assigned two conditions (Non-FES assist [NFA], FES assist [FA]) of walking. In all conditions, spatio-temporal parameters and kinematics and kinetics parameters during walking was collected via 3D motion capture system and 6 minutes walking test (6MWT) and metabolic cost during walking and stairs climbing was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Results: In Spatio-temporal parameters aspects, The EMG-controlled FES system significantly improved gait functions measurements of older adults with sarcopenia at walking in comparison to the NFA condition (P<0.05). Hip, knee and ankle joint range of motion increased at walking in FA condition compared to the NFA condition (P<0.05). In the FA condition, moment and ground reaction force was changed like normal gait during walking of older adults in comparison to the NFA condition (P<0.05). The EMG-controlled FES system significantly reduced net cardiopulmonary metabolic energy cost, net energy expenditure measurement at stairs climbing (P<0.05). Conclusions: This study demonstrated that EMG-controlled FES is a potentially useful gait-assist system for improving gait function by making joint range of motion and moment properly.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.77-84
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• 1992

The purpose of this study was to evaluate the diagnostic value of panoramic radiography for diagnosis of temporomandibular joint. Five dry skulls were selected for this study and artificial osteophyte was attached to four different areas of the mandibular condylar head. And then, the author had taken panoramic radiographs with the head in conventional position, 25㎜ forward position and reverse position in mouth opening state. Three dental radiologists evaluated the radiographic images of osteophyte in 60 panoramic radiographs. The results were as follows: In conventional position, osteophyte on the anterolateral and anterocentral area of the condylar head was best seen (p<0.01). In 25㎜ forward position, osteophyte on the anterocentral and anteromedial area was best seen (p<0.05). In reverse position, osteophyte on the anterocentral area was best seen (p<0.05). Osteophyte on anteromedial area was better seen in 25㎜ forward position than in conventional position (p<0.05).

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.473-477
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• 2007

Industry for artificial joint is a complex one based on various technologies, including mechanics, biotechnology, material engineering, and medicine which are connected closely. This industry has been already known to a higher value-added business, and as going into an aging society, is expected a market growth. Also, it is a knowledge based component industry and each components assembled into product is almost all import items. This characteristics made many small and medium and venture enterprises participate in this area. For these reasons, it is needed a government's promotion. In this study, commercialization environment was analyzed and then commercialization items and strategies was figured out. Firstly, three factors for need, environment, technology were analyzed and then growth drivers growth restraints were provided. Secondly, items and strategies for commercialization were analyzed based on needs and trends of technology. Commercialization opportunities are expected to be created based on strategies following as; building a integrated technology development system, making a public opinion, strengthening a marketing, entering into niche market, B2B strategies etc.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.108-115
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• 2009

In metal forming technologies, the stamping process is one of the significant manufacturing processes to produce sheet metal components. It is important to design stamping process which can produce sound products without defect such as fracture and wrinkle. The objective of this study is to propose the feasible formability diagram which denotes the safe region without fracture and wrinkle for effective design of stamping process. To determine the feasible formability diagram, FE-analyses were firstly performed for the combinations of process parameters and then the characteristic values for fracture and wrinkle were estimated from the results of FE-analyses based on forming limit diagram. The characteristic values were extended through training of the artificial neural network. The feasible formability diagram was finally determined for various combinations of process parameters. The stamping process of turret suspension to support suspension module was taken as an example to verify the effectiveness of feasible formability diagram. The results of FE-analyses for process conditions within fracture and wrinkle as well as safe regions were in good agreement with experimental ones.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.121-142
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• 1983

Recently mycorrhizal research has been one of the most fast-growing research areas in modern plant science and microbiology. The application potential of mycorrhizal techniques to agriculture and forestry is enormous in view of the ubiquitous nature of mycorrhizae and known benefits of mycorrhizae to host plants. Unfortunately, very few scientists in Korea are currently involved in mycorrhizal research. When a team of American plant pathologists visited Korea in September 1982 to participate in the Korea-U.S.A. Joint Seminar on Forest Diseases and Insect Pests, they were surprised by the principal author's statement that there was no single research project on mycorrhizae sponsored by Korean government or any scientific institutions. The author initiated a few years ago a research project on the ecology of tree mycorrhizae with a foreign financial support. Major areas of interest were survey of ectomycorrhizae in relation to soil fertility, taxonomic distribution of mycorrhizae among woody plants, identification of ectomycorrhizal fungi, and growth response of woody plants to artificial inoculation. In spite of the enormous application potential of mycorrhizae to agronomic plants, the subject of mycorrhizae has not been recognized by Korean agronomists, foresters or pathologists. The purpose of this review rather written in Korean is to introduce the techniques of mycorrhizal research to Korean scientists and to urge them to participate in challenging new scientific field which might bring us a remarkable increase in crop productivity and tree growth through manipulation of this unique symbiosis. In this review, following topics were discussed in the same order: introduction; brief history of mycorrhizal research; morphology and classification of mycorrhizae; distribution of mycorrhizae in plant kingdom and in soil profile; physiology of mycorrhizae (functions, mineral nutrition, mycorrhizal formation); interaction of mycorrhizae with soil-born plant pathogens. mycorrhizae in nitrogen-fixing plants; application of mycorrhizal techniques to nursery practices (isolation, culture, inoculation, and response); prospect in the future.

• Tunnel and Underground Space
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• v.31 no.4
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• pp.211-220
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• 2021

Tunnel collapse often occurs during deep underground tunneling (> 40 m depth) in South Korea. Natural cavities as well as water supply pipes, sewer pipes, electric power cables, artificial cavities created by subway construction are complexly distributed in the artificial ground in the shallow depths of the urban area. For deep tunnel excavation, it is necessary to understand the properties of the ground which is characterized by porous elements and various geological structures, and their influence on the stability of the ground. This study analyzed geological factors for risk assessment in deep excavation in South Korea based on domestic and overseas case study. As a result, a total of 7 categories and 38 factors were derived. Factors with high weights were fault and fault clay, differential stress, rock type, groundwater and mud inrush, uniaxial compressive strength, cross-sectional area of tunnel, overburden thickness, karst and valley terrain, fold, limestone alternation, fluctuation of groundwater table, tunnel depth, dyke, RQD, joint characteristics, anisotropy, rockburst and so forth.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.1-9
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• 2022

In this paper, we propose the Deep Learning-Based Companion Animal Abnormal Behavior Detection Service, which using video and sensor data. Due to the recent increase in households with companion animals, the pet tech industry with artificial intelligence is growing in the existing food and medical-oriented companion animal market. In this study, companion animal behavior was classified and abnormal behavior was detected based on a deep learning model using various data for health management of companion animals through artificial intelligence. Video data and sensor data of companion animals are collected using CCTV and the manufactured pet wearable device, and used as input data for the model. Image data was processed by combining the YOLO(You Only Look Once) model and DeepLabCut for extracting joint coordinates to detect companion animal objects for behavior classification. Also, in order to process sensor data, GAT(Graph Attention Network), which can identify the correlation and characteristics of each sensor, was used.

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.166-178
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• 2006

Recently, the frequency of occurring dynamic events such as earthquakes, explosives blasting and other types of vibration has been increasing. Besides, the chances of exposure for rock discontinuities to free faces get higher as the scale of rock mass structures become larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, artificially fractured rock joint specimens were prepared in order to examine the dynamic frictional behavior of rough rock joint. Roughness of each specimen was characterized by measuring surface topography using a laser profilometer and a series of shaking table tests was carried out. For mated joints, the static friction angle back-calculated ken the yield acceleration was $2.7^{\circ}$ lower than the tilt angle on average. The averaged dynamic friction angle for unmated joints was $1.8^{\circ}$ lower than the tilt angle. Displacement patterns of sliding block were classified into 4 types and proved to be related to the first order asperity of rock joint. The tilt angle and the static friction angle for mated joints seem to be correlated to micro average inclination angle which represents the second order asperity. The tilt angle and the dynamic friction angle for unmated Joints, however, have no correlation with roughness parameters. Friction angles obtained by shaking table test were lower than those by direct shear test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.773-782
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• 2020

The development of joint FE models for deep learning neural network (DLNN)-based hybrid FEA is presented. Material models of bolts and bearings in the front axle of tractor, showing complex behavior induced by various tightening conditions, were replaced with DLNN models. Bolts are modeled as one-dimensional Timoshenko beam elements with six degrees of freedom, and bearings as three-dimensional solid elements. Stress-strain data were extracted from all elements after finite element analysis subjected to various load conditions, and DLNN for bolts and bearing were trained with Tensorflow. The DLNN-based joint models were implemented in the ABAQUS user subroutines where stresses from the next increment are updated and the algorithmic tangent stiffness matrix is calculated. Generalization of the trained DLNN in the FE model was verified by subjecting it to a new loading condition. Finally, the DLNN-based FEA for the front axle of the tractor was conducted and the feasibility was verified by comparing with results of a static structural experiment of the actual tractor.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.363-367
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• 2003

Contact area and pressure are important factors which directly influence a life of knee implants. Since implant's mechanical functions should be experimentally evaluated for clinical use, many studies using a knee simulator and a pressure sensor system have been conducted. However it has not been reported that the contact pressure's distribution of a knee implant motion was estimated in real-time during a gate cycle. Therefore. the objective of this study was to analyze the contact pressure distribution for the motion of a joint using the knee simulator and I-scan sensor system. For this purpose, we developed a force-controlled dynamic knee simulator to evaluate the mechanical performance of artificial knee joint. This simulator includes a function of a soft tissue and has a 4-degree-of-freedom to represent an axial compressive load and a flexion angle. As axial compressive force and a flexion angle of the femoral component can be controlled by PC program. The pressure is also measured from I-scan system and simulator to visualize the pressure distribution on the joint contact surfaces under loading condition during walking cycle. The compressive loading curve was the major cause for the contact pressure distribution and its center move in a cycle as to a flexion angie. In conclusion, this system can be used to evaluate to the geometric interaction of femoral and tibial design due to a measured mechanical function such as a contact pressure, contact area and a motion of a loading center.