• Korean Journal of Radiology
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• v.22 no.4
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• pp.612-623
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• 2021

Objective: To evaluate the diagnostic performance of a deep learning algorithm for the automated detection of developmental dysplasia of the hip (DDH) on anteroposterior (AP) radiographs. Materials and Methods: Of 2601 hip AP radiographs, 5076 cropped unilateral hip joint images were used to construct a dataset that was further divided into training (80%), validation (10%), or test sets (10%). Three radiologists were asked to label the hip images as normal or DDH. To investigate the diagnostic performance of the deep learning algorithm, we calculated the receiver operating characteristics (ROC), precision-recall curve (PRC) plots, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) and compared them with the performance of radiologists with different levels of experience. Results: The area under the ROC plot generated by the deep learning algorithm and radiologists was 0.988 and 0.988-0.919, respectively. The area under the PRC plot generated by the deep learning algorithm and radiologists was 0.973 and 0.618-0.958, respectively. The sensitivity, specificity, PPV, and NPV of the proposed deep learning algorithm were 98.0, 98.1, 84.5, and 99.8%, respectively. There was no significant difference in the diagnosis of DDH by the algorithm and the radiologist with experience in pediatric radiology (p = 0.180). However, the proposed model showed higher sensitivity, specificity, and PPV, compared to the radiologist without experience in pediatric radiology (p < 0.001). Conclusion: The proposed deep learning algorithm provided an accurate diagnosis of DDH on hip radiographs, which was comparable to the diagnosis by an experienced radiologist.

• Journal of Life Science
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• v.14 no.3
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• pp.484-489
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• 2004

Artificial joint replacement is one of the major surgical advances of the 21th century. The primary purpose of a TKA (Total Knee Arthroplasty) is to restore normal knee Auction. Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from a chair or climbing stairs;(b) allow the same range of motion as an complete knee; and (c) provide adequate knee joint stability. Four individuals (2 peoples after surgery one year and 2 peoples after surgery three years) participated in this study. All they were prescreened for health and functional status by the same surgeon who performed the operations. Two days of accommodation practice occurred prior to the actual strength testing. The isometric strength (KIN-COM III) of the quadriceps and hamstring were measured at 60$^\circ$ and 30$^\circ$ of knee flexion, respectively. During isokinetic concentric testing, the range of motion was between 10$^\circ$ to 80$^\circ$ of knee flexion (stand-to-sit) and extension (sit-to-stand). for a given test, the trial exhibiting maximum torque was analyzed. A 16-channel MYOPACTM EMG system (Run Technologies, Inc.) was used to collect the differential input surface electromyographic (EMG) signals of the vastus medialis (VM), vastus lateralis(VL), rectus femoris (RF) during sit-to-stand and stand-to-sit tests. Disposable electrodes (Blue SensorTM, Medicotest, Inc.) were used to collect the EMG signals. The results were as follows; 1. Less maximum concentric (16% and 21% less for 1 yew man and 3 years mm, respectively) and isometric (12% and 29%, respectively) quadriceps torque for both participants. 2.14% less maximum hamstrings concentric torque for 1 year man but 16% greater torque for 3 years mm. However, 1 year man had similar hamstring isometric peak torque for both knees. 3. Less quadriceps co-contraction by 1 year man except for the VM at 10$^\circ$-20$^\circ$ and 30$^\circ$-50$^\circ$ range of knee flexion.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.604-611
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• 2014

The purpose of this study was to assess the consumption of aspartame and acesulfame K, the most frequently utilized artificial sweeteners in Korea. The contents of aspartame and acesulfame K in processed foodstuffs were analyzed by HPLC, and daily intakes according to sex and age were estimated by applying the consumption data from the Korea National Health and Nutrition Examination Survey. Estimated daily intakes of aspartame and acesulfame K were 58.37 ${\mu}g/kg$ bw/day and 14.23 ${\mu}g/kg$ bw/day, respectively, in 2012. These amounts constituted 0.15% and 0.09% of the ADI (Acceptable Daily Intake) established by the JECFA (FAO/WHO Joint Expert Committee on Food Additives). Estimated daily intakes of aspartame and acesulfame K in the 95 percentile consumption group were 2,510.48 ${\mu}g/kg$ bw/day and 761.92 ${\mu}g/kg$ bw/day, respectively, and intake levels were 6.28% and 5.08% of the ADI, respectively. In conclusion, daily intake levels of artificial sweeteners were evaluated to be at safe levels.

• Journal of Korean Medicine Rehabilitation
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• v.15 no.1
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• pp.127-141
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• 2005

Objectives : This study was performed to investigate the effects of Gamichangbaek-san(Jiaweichangbai-san) on anti-inflammatory, analgesic, anti-febrile and immune response on the arthritis of carrageenan-induced animals. Methods and Materials : Rats were classified into control and sample groups which are 7 individuals each for the experiments about anti-inflammatory and anti-febrile. Each of the 7 mice were classified into normal, control, sample groups for the analgesic experiments. Gamichangbai-san(Jiaweichangbai-san) was administered to sample group and normal saline was administered to normal and control groups. Arthritis was induced by injection of 1% carrageenan $0.1m{\ell}$ and Gamichangbaek-san(Jiaweichangbai-san) was administered after 30 minutes. The change of edema in Carrageenan-induced Arthritic Rats' Paws was measured after 1 hour and 5 hours from the injection of carraqeenan with Plethysmometer(7150, UGO BASILE, ltaly) by Winter' method. WBC, Lymphocyte and ESR were measured by heart puncture and CD4+ T cell, CD8+ T cell and CD4+/CD8+ T cell ratio were measured from the spleen tissue. Writhing syndrom was measured with Tail flick unit(UGO BASILE, Italy) in the experiments conducted to check the analgesic activity. The temperature of the paws of carrageenan-induced arthritic rats was measured by Laser thermometer. Rectal temperature was measured by Yeast's method in anti-febrile experiments. Immune response was measured by CD4+, CD8+ T cell ratio and CD4+/CD8+ T cell ratio. Results : 1. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased the increase rate of Paw Edema effectively with statistical significance. 2. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased WBC, Lymphocyte and ESR with statistically high significance. 3. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) did not show significant analgesic effect, but the Pressure pain threshold of the paws was increased with statistical significance. 4. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased rectal temperature effectively and had an anti-febrile effect about the febrile of a joint with statistical significance. 5. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) increased CD4+ T cell ratio with statistically high significance and increased CD+8 T cell ratio with statistical non significance but increased CD4+/CD8+ T cell ratio effectively with statistical significance, too. Conclusions : According to the above results, it can be concluded Gamichangbaek-san(Jiaweichangbai-san) showed the treatment effects on the artificial arthritis resulted from carageenan in rats and it is suggested that more interest and study in the security for the clinical use were needed.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.217-226
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• 2007

Putting score counts about 43 % of the golf score. The dominant idea of the putting motion to amateur golfers as well as to many professional golfers is a pendulum-like motion. If a golfer's putting stroke motion is a pendulum-like motion, the putting motion should be straight-back-and-through, the same backswing, downswing, and follow through length and period, and a swing with a fixed hinge joint. If the putting motions of the human are different from the pendulum motion, there could be confusion in understanding and teaching golf putting. The purpose of this study was to examine the center of rotation(COR) of the putter head to reveal whether professional golfers really putt like a pendulum. Thirteen male professional golfers were recruited for the study. Each golfers executed 10.94 m putts six times on an artificial grass mat. Putter head position data were collected through a 60 Hz three-dimensional motion analysis system and low pass filtered with cut-off frequency of 6 Hz. COR of the putter head was mathematically acquired. Each golfer's last five putting motions were considered. The results show that the COR of the putter head was neither fixed nor located inside of the golfer. The medio-lateral directional component of the COR of the putter head fluctuated in the range of 10 cm during downswing and follow through. The anterior-posterior directional component of the COR of the putter head was fixed from the beginning of the downswing through impact. Just after impact, however, it moved to the target up to 60 cm. The superior-inferior directional component of COR of the putter head moved in a superior direction with the beginning of the downswing and showed peak height just prior to impact. During the follow through, it moved back in an inferior direction. The height-normalized peak value of the COR of the putter head was $1.4{\pm}0.3$ height. Technically speaking, male professional golfers' 10.94 m putting motion is not a pendulum-like motion. The dominating idea of a pendulum-like motion in putting might come from the image of the flawless, smooth motion of a pendulum.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1061-1073
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• 2017

In this study, images were classified using convolutional neural network (CNN) - a deep learning technique - to investigate the feasibility of information production through a combination of artificial intelligence and spatial data. CNN determines kernel attributes based on a classification criterion and extracts information from feature maps to classify each pixel. In this study, a CNN network was constructed to classify materials with similar spectral characteristics and attribute information; this is difficult to achieve by conventional image processing techniques. A Compact Airborne Spectrographic Imager(CASI) and an Airborne Imaging Spectrometer for Application (AISA) were used on the following three study sites to test this method: Site 1, Site 2, and Site 3. Site 1 and Site 2 were agricultural lands covered in various crops,such as potato, onion, and rice. Site 3 included different buildings,such as single and joint residential facilities. Results indicated that the classification of crop species at Site 1 and Site 2 using this method yielded accuracies of 96% and 99%, respectively. At Site 3, the designation of buildings according to their purpose yielded an accuracy of 96%. Using a combination of existing land cover maps and spatial data, we propose a thematic environmental map that provides seasonal crop types and facilitates the creation of a land cover map.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.25-34
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• 2010

A method is presented for evaluating the seismic failure probability of bridge structures which show a nonlinear hysteretic dynamic behavior. Bridge structures are modeled as a bilinear dynamic system with a single degree of freedom. We regarded that the failure of bridges will occur when the displacement response of a deck level firstly crosses the predefined limit state during a duration of strong motion. For the estimation of the first-crossing probability of a nonlinear structural system excited by earthquake motion, we computed the average frequency of crossings of the limit state. We presented the non-Gaussian closure method for the approximation of the joint probability density function of response and its derivative, which is required for the estimation of the average frequency of crossings. The failure probabilities are estimated according to the various artificial earthquake acceleration sets representing specific seismic characteristics. For the verification of the accuracy and efficiency of presented method, we compared the estimated failure probabilities with the results evaluated from previous methods and the exact values estimated with the crude Monte-Carlo simulation method.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.99-106
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• 1999

Ultra-high molecular weight polyethylene (UHMWPE) was crosslinked in the melt state to enhance wear resistance, Dicumyl peroxide (DCP) and triallyl cyanurate (TAC) was used as a crosslinking agent and a promoter, respectively. With increasing amount of DCP and TAC used, gel content of crosslinked UHMWPE (XUMPE) increased, while the melting temperature, crystallizaiton temperature, crystallinity, and tensile properties decreased. The results of pin-on-disk wear test and ball-on-disk test with small applied load showed reduced wear volumes of XUMPE from that of the unmodified UHMWPE. As the wear mechanism effected in the experimental condition of this study was thought to be deformation rather than adhesion or fatigue, a new parameter, the ratio of maximum contact stress to yield stress, was proposed to correlate well with observed wear resistance. In ball-on-disk wear test with larger applied load, XUMPE showed higher wear volumes than that of the unmodified UHMWPE which were accompanied with increased friction coefficients and surface roughness of the wear tracks. When contact stress was well above yield stress, the failure of XUMPE, as well as deformation, was thought to be much accelerated.

• Information Systems Review
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• v.22 no.2
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• pp.77-99
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• 2020

Smart speaker is a device that provides an interactive voice-based service that can search and use various information and contents such as music, calendar, weather, and merchandise using artificial intelligence. Since AI technology provides more sophisticated and optimized services to users by accumulating data, early smart speaker manufacturers tried to build a platform through aggressive marketing. However, the frequency of using smart speakers is less than once a month, accounting for more than one third of the total, and user satisfaction is only 49%. Accordingly, the necessity of strengthening the user experience of smart speakers has emerged in order to acquire a large number of users and to enable continuous use. Therefore, this study analyzes the user experience of the smart speaker and proposes a method for enhancing the user experience of the smart speaker. Based on the analysis results in two stages, we propose ways to enhance the user experience of smart speakers by model. The existing research on the user experience of the smart speaker was mainly conducted by survey and interview-based research, whereas this study collected the actual review data written by the user. Also, this study interpreted the analysis result based on the smart speaker user experience dimension. There is an academic significance in interpreting the text mining results by developing the smart speaker user experience dimension. Based on the results of this study, we can suggest strategies for enhancing the user experience to smart speaker manufacturers.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.697-714
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• 2023

The Tracksite of Cretaceous Dinosaurs and Pterosaurs in Jeongchon, Jinju was discovered in late 2017 during the construction of the Ppuri industry complex. This site is a natural heritage site with a high paleontological value, as it preserves fossils of various types of dinosaurs, pterosaurs, and animal traces at a dense concentration. In this study, we surveyed that physical weathering such as joint, crack, scaling, exfoliation, and fragmentation occurred through field research in the fossil site, and conducted basic research on conservation science to reduce the damage. To this end, among the eight levels identified after excavation, the rocks of Level 3, which yielded a large number of theropod footprint fossils, and Level 4, which yielded pterosaur footprint fossils, were analyzed for material characteristics and evaluation of the effectiveness of consolidation and adhesion. This results showed that the rocks in the Level 3 stratum were dark gray siltstone and the rocks in the Level 4 stratum were dark gray shale, which contained a large amount of calcite and were composed of quartz, plagioclase, mica, alkali feldspar, and other clay minerals, which are likely to be damaged by rainfall under external conditions. As a result of conducting an artificial weathering experiment by dividing the probationary sample into four groups: untreated, consolidation treatment, anti-swelling treatment, and adhesive treatment, the consolidation and the swelling inhibitor showed an effect immediately after treatment, but did not show a blocking effect under a freezing-thawing environment. The adhesive showed that the adhesive effect was maintained even under freezing-thawing conditions. In order to preserve the fossil sites at Jeongchon in the future, in addition to temporary measures to block the inflow of moisture, practical measures such as the construction of protective facilities should be prepared.