• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.582-590
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• 2007

Nonlinear adaptive control of overhead cranes is investigated for anti-sway trajectory tracking with high-speed hoisting motion. The sway dynamics of two dimensional underactuated overhead cranes is heavily coupled with the trolley acceleration, hoisting rope length, and the hoisting velocity which is an obstacle in the design of decoupling control based anti-sway trajectory tracking control law To cope with this obstacle. we propose a fuzzy nonlinear adaptive anti-sway trajectory tracking control law guaranteeing the uniform ultimate boundedness of the sway dynamics even in the presence of uncertainties in such a way that it cancels the effect of the trolley acceleration and hoisting velocity on the sway dynamics. In particular. system uncertainties, including system parameter uncertainty unmodelled dynamics, and external disturbances, are compensated in an adaptive manner by utilizing fuzzy uncertainty observers. Accordingly, the ultimate bound of the tracking errors and the sway angle decrease to zero when the fuzzy approximation errors decrease to zero. Finally, numerical simulations are performed to confirm the effectiveness of the proposed scheme.

• The Journal of the Petrological Society of Korea
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• v.1 no.1
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• pp.34-41
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• 1992

The Precambrian granitic gneisses are widely distributed in the Danyang-Yecheon area, eastern part of Korea, where the Ryeongnam massif borders the Ogcheon fold belt. They are composed of migmatitic, biotite granitic, garnet-bearing and granoblastic granitic gneisses. The common joint sets of the granitic gneiss are NE and NS directions, which are probably related to the effects of Daebo orogeny and Bulgugsa disturbance, respectively. Mineral assemblages of the banded gneiss xenolith in the garnet-bearing granitic gneiss are quartz-plagioc1ase-biotite-mus-covite-orthoclase and quartz-plagioc1ase-biotite-garnet, belonging to the amphibolite facies. The granoblastic granitic gneiss is felsic, metaluminous, and granitic, and shows subalkaline trend. The garnet-biotite geothermometry of garnet-bearing granitic gneiss yields 640$^{\circ}$-708$^{\circ}C$ at pressure of 4 kb.

• Journal of Navigation and Port Research
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• v.45 no.3
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• pp.87-94
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• 2021

The IMO has adopted emission standards that strictly restrict the use of bunker C oil for vessels. Accordingly, research and bunkering pilot projects for LNG fueled ships are being actively carried out, which is expected to substantially reduce environmental pollution. In this study, we have adopted the turret moored Floating LNG Bunkering Terminal (FLBT) designed to receive the LNG from LNGCs and to transfer LNG to LNG bunkering shuttles in ship to ship moored condition. Numerical simulations have been performed with a 1-year return period of wind, wave, and current. Damping values of numerical model were adjusted from the results of model tests to obtain accurate simulation results. The results confirm safe berthing operation during the 1-year return period of environmental condition. Safety depends on the direction of environment, with increasingly stable operation facilitated by the application of heading-control function of FLBT to avoid beam-sea conditions.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.313-318
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• 2019

The purpose of this study is to investigate whether there is a difference in the incidence of the black circle border of iris(skin disease) according to the iris constitution. Iris was taken for 100 adults living in Seoul. Iris was photographed using the iris camera DV-2H, a blue focus development product. Statistical significance was tested by correlation analysis, and the occurrence of black circle border of iris was low negative correlation(p<0.01). As mentioned above, we know that the occurrence of black circle border of iris differs according to the iris constitution, and by using it actively, it will help health promotion about skin. There is a need to study the changes of iris in the cause of skin disease by using a blood test to analyze the cause of the skin disease in the future.

• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.41-47
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• 2018

The buoy-enabled underwater surveillance system is a device that is installed in a particular sea area and operated for a certain period of tine and moved to another sea area after recovery. In this paper, a mooring method which is applied for a buoy-enabled underwater surveillance system was selected to maintain installation and enure stable operation. Also, the structure of the mooring line was designed. Two-point mooring method was selected considering interference with the communication cable of array-assembly. The composite structure of buoy chain, nylon rope, and anchor chain is designed as the basic component of mooring line. For the verification of design, a numerical simulation and wave tank experiment were performed. Their results were confirmed similarity in test condition. Finally, the mooring lines were designed for the environment of the sea trial location. The mooring line produced by the final design confirmed the stability above the significant wave height considered in the design on the sea trial.

• Tribology and Lubricants
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• v.34 no.6
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• pp.270-278
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• 2018

STS 316L prepared by additive manufacturing (AM) exhibits deterioration of mechanical properties and wear resistance due to the presence of defects such as black-of-fusion defects, internal porosity, residual stress, and anisotropy. In addition, high surface roughness (integrity) of AM products remains an issue. This study aimed to apply ultrasonic nanocrystal surface modification (UNSM) technology to STS 316L prepared by AM to increase the surface hardness, to reduce the surface roughness, and to improve the friction and wear behavior to the level achieved by bulk material manufactured using traditional processes. Herein, the as-received and polished specimens were treated by UNSM technology and their resulting properties were compared and discussed. The results showed that UNSM technology increased the surface hardness and reduced the surface roughness of the as-received and polished specimens. These results can be attributed to grain size refinement and pore elimination from the surface. Moreover, the friction of the as-received and polished specimens after UNSM technology was lower compared to those of the as-received and polished specimens, but no significant differences in wear resistance were found.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.423-432
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• 2019

The purpose of this study was to investigate the effect of cushion insole on lumbar flexibility and motor fitness in patients with lumbar spinal stenosis. 26 patients with lumbar spinal stenosis were randomly assigned to the experimental group 13 and the control group 13. Volunteers were allowed to wear cushioned insoles for two hours a day for six weeks. The experimental group was 8 mm and the control group was 4 mm, wearing a cushion insole as a blinded experiment. There was a significant increase(p<0.05) in the flexion test of the experimental group ($3.38{\pm}3.12$), but not statistically significant in the other tests(p>0.05). In conclusion, cushion insole was not suitable for intervention for lumbar spinal stenosis. There is a need to study the height and material of the insoles in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.102-110
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• 2019

This study is for the elderly with mental and physical dysfunction, developing resistance exercise program using tube elasticity, and analysing the effects of this movement on the improvement of gait ability, balance ability and muscle strength of the elderly. After a 12-week program for 58 participants of the daycare center, dependent t-test was performed. As a result, the total participants showed average improvement in gait, balancing and hand grip strength. This means a lot in terms of improving one's ability of ADL(Activities of daily living) and reducing the risk of falling. Therefore, if the program expands and activates the target as an entire elderly, it is expected to be a preventative way to prevent healthy elderly people from moving to the frailty who need treatment and to delay the deterioration of the frailty with disabilities.

• Journal of Society of Preventive Korean Medicine
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• v.23 no.1
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• pp.1-13
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• 2019

Backgrounds : The market of Complementary Alternative Medicine(CAM) in the United State(U.S.) accounts for a large proportion of the global CAM market and has a high growth rate. The recent introduction of Obama Care has brought the change in the health insurance system for CAM, and we need to analyze it for its implication to Korean system. Objectives : The purpose of this study is to investigate the current status of acupuncture and chiropractic health insurance in the U.S., and to draw implications for expanding the health insurance coverage for Korean traditional medicine through the comparison between the U.S. and Korean health insurance systems. Methods : We examined the data through the literature search and from the websites of both U.S. government departments and related organizations for the health insurance policy. Based on the collected data, we analyzed its CAM health insurance system in Korea. Results : The acupuncture covered by public health insurance in the U.S. has a limit in the number of treatments and a range of applied diseases compared with Korea. In addition, the practice of acupuncture is not subdivided. However, the chiropractic in the U.S. which also has a limited number of coverage and only three categories of practices are similar to that of Korea. Conclusions : Although the use of CAM by public health insurance is not active in the U.S., but the organizations such as Veterans Health Administration in Vermont is already discussing the use of acupuncture to solve the problem of opioid overuse. Thus Korea also needs to discuss to promote the expansion of the insurance system for CAM.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.57-64
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• 2019

A man-made slope has been increased due to the construction of road. This slope lies at risk of rock falling, induced mostly by heavy rainfall. The MOLIT (Ministry of Land, Infrastructure and Transport) recommends the specific dimension of rockfall protection fence (post, wire-rope, and mesh) which should resist 48~61 kJ. However, the energy absorption capacity of each component of rockfall protection fence is not clearly presented. Hence, this study made an effort to compute the energy absorption capacity of each component in analytical and numerical method, and compared with each other.