• Journal of Korean Orthopaedic Sports Medicine
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• v.7 no.1
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• pp.27-32
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• 2008

Purpose: To evaluate the clinical results of the patients who underwent radiofrequency thermal shrinkage (RFTS) for treatment of anterior cruciate ligament (ACL) laxity after ACL reconstruction. Material and Methods: From October 1999 to March 2006, we performed 133 cases of ACL reconstruction. Among them we experienced 16 patients who had the laxity of reconstructed ACL in second look arthroscopy. Mean follow-up was 20.4 months. Mean age was 33.5 years. 12 cases were male and 4 cases were female. The elongated ACL were treated by bipolar radiofrequency energy with an output of grade II. Subjective and objective parameters were utilized in analyses, such as: the mean range of motion, Lysholm knee score, Tegner activity score, Lachman test, IKDC score. Wilcoxon signed-rank test was used to perform the data analysis. P<0.05 was considered to be statistically significant. Results: Postoperative mean Lysholm knee score (preop: $82.2{\pm}5.2(77{\sim}85))$ (P=0.04), postop: $85.2{\pm}4.8$(82-90)) and anterior displacement by the Telos stress test (preop: $5.4{\pm}4.6(3{\sim}10)mm$, postop: $2.1{\pm}1.9(0{\sim}4)mm)$ (P=0.02), Lachman's test, and IKDC scores (P=0.04) demonstrated significant differences statistically compared to the preoperative. There were no statistical differences in mean range of motion, Tegner activity scale. Conclusions: Arthroscopic shrinkage for the ACL laxity after ACL reconstruction with radiofrequency device showed good clinical results and was applicable operative technique.

• The Journal of Korean Academy of Sensory Integration
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• v.6 no.1
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• pp.1-12
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• 2008

Objective : The purpose of this study is to provide reference to functional level of sensory integration of in the low-grads school age, based on the Clinical Observation of Motor and Postural Skills (COMPS) and to examine correlation between the function of sensory integration and academic achievement. Method : Two schools ("J" and "S") have been selected indiscriminately among 56 elementary schools located in Gimhae-si, GyeongNam and then one class from each school was voluntarily chosen among all second-grade classes of the schools. The total number of students in those two classes was 69 (34 boys and 35 girls). Subjects had no developmental problem and no history of referral regarding neurological conditions. Three skilled researchers administrated the COMPS together, and each researcher executed two sub-items of the COMPS. As result of the academic achievement, score data of midterm- and final-exam in the spring semester were collected. The scores of 'Korean language' and 'Math', common examination subjects in both schools, were utilized for data analysis in this study. Results : Statically, there was no significant correlation between the COMPS Weighted Scores and any academic achievements. In a dispersion graphic analysis, however, the total achievement showed significant negative-correlation with the area of 'Rapid Forearm Rotation' and significant positive-correlation with the area of 'Supine Flexion'. In terms of the Math achievement, there are significant negative-correlation with rapid forearm rotation and asymmetrical tonic neck reflex, and significant positive-correlation with the area of 'Supine Flexion'. Students with higher score of the Korean language showed a tendency to get higher Weighted Score and Minus Adjustment Score, and those with lower score of the Math showed a tendency to get higher COMPS scores in all area except the area of 'Supine Flexion'. There was a statically significant difference in the COMPS scores depend on the age among general characteristics. As student older, all COMPS scores, except those in the area of 'Slow Motion' and 'Supine Flexion, were higher. Conclusions : There is somehow reliable correlation between sensory integration function and academic achievement although no statistical significance found in this study. The information from this study may contribute to initiate developing a normative-reference to screen earlier and more alertly sensory integration dysfunctions for school-age children. Further study is recommended trying to find out more reliable matter regarding low grade- schooler's academic achievement.

• The Korean Journal of Air & Space Law and Policy
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• v.23 no.2
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• pp.115-136
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• 2008

The development of the aviation technology is beyond the people's imagination. For example, with some exaggeration, If the autopilot engage upon take off, You will realize that you are on the centerline of the foggy JFK runway 13R after 15 hours with only once or twice of intervention. But the more aviation technology develops, the more responsible the pilot will be who has the final authority of the aviation safety. In the JAL 706 accident caused by unidentified reason, the pilot increased pitch abruptly and overrode the control from the autopilot. The result of this process made the death of a flight attendant and some injuries of a few passengers. The district court found the pilot not guilty at the first trial on the ground that the control override was not connected to the possibility of foresight and avoidance of the human death. The pilot was proved to be innocent through the analysis of the DFDR and ADAS that the override did not precede the unidentified pitch up motion. The judicial precedent related to aviation accidents in Korea requires pilots' absolute and extended care compared to the ordinarily prudent or reasonably careful behaviors in the vehicle and medical accidents. Although there is some controversy about the standard care, the care required in the actual operation of high tech aircraft by a pilot should include objective and standard care and be judged by analysis of the scientific data. Although the pilot maintained the unusual hi speed that doesn't have safety margin and descended under turbulence in case of the JAL 706 accident, the court negatived its relation to the cause of pitch up. Also, the override of the control after initial pitch up might have caused the possibility of the death and injury, but the court denied it. Because of this complex cause of the aviation accidents, it is important for a court to figure out the core reason of the event and casual relationship with the pilot Now, It is required that the judgement of negligence in the aviation accidents should include an objective care with scientific data from simulated circumstances(or a simulator) as the Japanese court not from the theory of vehicle's negligence.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.424-429
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• 2009

This study aimed to assess the influence of different cross-sectional area on the cyclic fatigue fracture of Ni-Ti rotary files using a fatigue tester incorporating cyclical axial movement. Six brands of Ni-Ti rotary files (ISO 30 size with. 04 taper) of 10 each were tested: Alpha system (KOMET), HeroShaper (MicroMega), K3 (SybronEndo), Mtwo (VDW), NRT (Mani), and ProFile (Dentsply). A fatigue-tester (Denbotix) was designed to allow cyclic tension and compressive stress on the tip of the instrument. Each file was mounted on a torque controlled motor (Aseptico) using a 1:20 reduction contra-angle and was rotated at 300 rpm with a continuous, 6 mm axial oscillating motion inside an artificial steel canal. The canal had a $60^{\circ}$ angle and a 5 mm radius of curvature. Instrument fracture was visually detected and the time until fracture was recorded by a digital stop watch. The data were analyzed statistically. Fractographic analysis of all fractured surfaces was performed to determine the fracture modes using a scanning electron microscope. Cross-sectional area at 3 mm from the tip of 3 unused Ni-Ti instruments for each group was calculated using Image-Pro Plus (Imagej 1.34n, NIH). Results showed that NRT and ProFile had significantly longer time to fracture compared to the other groups (p < .05). The cross-sectional area was not significantly associated with fatigue resistance. Fractographycally, all fractured surfaces demonstrated a combination of ductile and brittle fracture. In conclusion, there was no significant relationship between fatigue resistance and the cross-sectional area of Ni-Ti instruments under experimental conditions.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.111-119
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• 2019

The high-speed railway system is mainly composed of tunnel, bridge, and viaduct to meet the straightness needed for keeping the high speed up to 400 km/s. Seismic fragility for the high-speed railway infrastructure can be assessed as two ways: one way is studying each element of infrastructure analytically or numerically, but it requires lots of research efforts due to wide range of railway system. On the other hand, empirical method can be used to access the fragility of an entire system efficiently, which requires case history data. In this study, we collect the 2004 M_W 6.6 Niigata earthquake case history data to develop empirical seismic fragility function for a railway system. Five types of intensity measures (IMs) and damage levels are assigned to all segments of target system for which the unit length is 200 m. From statistical analysis, probability of exceedance for a certain damage level (DL) is calculated as a function of IM. For those probability data points, log-normal CDF is fitted using MLE method, which forms fragility function for each damage level of exceedance. Evaluating fragility functions calculated, we observe that T=3.0 spectral acceleration (SA_T3.0) is superior to other IMs, which has lower standard deviation of log-normal CDF and low error of the fit. This indicates that long-period ground motion has more impacts on railway infrastructure system such as tunnel and bridge. It is observed that when SA_T3.0 = 0.1 g, P(DL>1) = 2%, and SA_T3.0 = 0.2 g, P(DL>1) = 23.9%.

• Cartoon and Animation Studies
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• s.50
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• pp.43-73
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• 2018

This is a study on 'Objet' in animation culture art education. Research on the use of Objet in modern art is actively under way. From Cubism to Dadaism, Surrealism, Futurism and Pop art, it is no exaggeration to say that the Objet is stepping with modern art. In addition, Objet has a remarkable value in the field of visual arts expressing 'motion' such as kinetic art, video art, media art, and animation. However, there are not many cases of classifying and studying the types of Objets used in artworks. Therefore, this researcher has been influenced by the surrealism discourse and prepared six types of Objets type analysis framework. And the research focused on 'the aesthetic emotion and educational aspect of creativity improvement' of Objet animation was conducted. The type analysis framework is named as a drawing Objet, Objet of existence, a morphine Objet, epidermis Objet, assigned Objet and assemblage Objet and this type is presented and analyzed with case image. The data used in this study was focused on the outcome of Objet animation that were trained for non-experts in culture and arts education. This aesthetic emotion refers to Freud's desire for life (Eros) as Attraction, and desire for death (Thanatos) as Uncanny (fearful unfamiliarity) and explains the conflicting concept with the Animism, the indigenous religion. Next, educational aspects of Objet animation creativity improvement in relation to the term 'functional fixedness' was discussed as described by Gestalt psychologist Karl Duncker (1903-1940). Overcoming the functional fixedness is a phenomenon that is fixed only to the functional aspects of things and can't be changed. In this study, the educational aspect of creativity improvement was demonstrated as a case of overcoming the functional fixedness through 'Objet Animation' culture and art education. Ultimately, this study is to prove the aesthetic emotion and creativity of the Objet animation by analyzing Objet types. Furthermore, it is meaningful to suggest direction when using 'Objet Animation' in culture and arts education.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.421-430
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• 2004

Clinically, it is almost impossible for a physician to distinguish subtle changes of frequency spectrum by using a stethoscope alone especially in the early stage of thrombus formation. Considering that reliability of mechanical valve is paramount because the failure might end up with patient death, early detection of valve thrombus using noninvasive technique is important. Thus the study was designed to provide a tool for early noninvasive detection of valve thrombus by observing shift of frequency spectrum of acoustic signals with computer aid diagnosis system. A thrombus model was constructed on commercialized mechanical valves using polyurethane or silicon. Polyurethane coating was made on the valve surface, and silicon coating on the sewing ring of the valve. To simulate pannus formation, which is fibrous tissue overgrowth obstructing the valve orifice, the degree of silicone coating on the sewing ring varied from 20％, 40％, 60％ of orifice obstruction. In experiment system, acoustic signals from the valve were measured using microphone and amplifier. The microphone was attached to a coupler to remove environmental noise. Acoustic signals were sampled by an AID converter, frequency spectrum was obtained by the algorithm of spectral analysis. To quantitatively distinguish the frequency peak of the normal valve from that of the thrombosed valves, analysis using a neural network was employed. A return map was applied to evaluate continuous monitoring of valve motion cycle. The in-vivo data also obtained from animals with mechanical valves in circulatory devices as well as patients with mechanical valve replacement for 1 year or longer before. Each spectrum wave showed a primary and secondary peak. The secondary peak showed changes according to the thrombus model. In the mock as well as the animal study, both spectral analysis and 3-layer neural network could differentiate the normal valves from thrombosed valves. In the human study, one of 10 patients showed shift of frequency spectrum, however the presence of valve thrombus was yet to be determined. Conclusively, acoustic signal measurement can be of suggestive as a noninvasive diagnostic tool in early detection of mechanical valve thrombosis.

• Journal of Life Science
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• v.20 no.4
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• pp.543-548
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• 2010

The purpose of this study was to examine the differences in kinetics between 6 months of rehabilitation training and 12 months of rehabilitation training after total hip arthroplasty. 10 unilateral THA participants performed kinetic tests. Three dimensional kinematics and hip flexors and abductors electromyography (EMG) were collected during each trial. T-test was used for statistical analysis (p<0.05). There was no significant difference in EMG data between the two groups, but the mean comparison EMG data was higher in the 12 months rehabilitation training group than the 6 months rehabilitation training group. The moment value was found with motion-dependent interaction analyzing method which was used by Feltner and Dapena. There was no significant difference between moment values of the two groups. There was no significant difference between ground reaction forces of the two groups; however, there were some differences shown in Fz (vertical reaction force) between the two groups ($892{\pm}104\;N$, $820{\pm}87\;N$). The first peak impact force was about 9% lower in the 12 months group compared to the 6 months group. The second peak active force was nearly equal between the two groups. More research is necessary to determine exactly what constitutes optimal rehabilitation training biomechanics for patients with total hip arthroplasty.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.174-183
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• 2014

Seabed beneath and near coastal structures may undergo large excess pore water pressure composed of oscillatory and residual components in the case of long durations of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. If liquefaction occurs in the seabed, the structure may sink, overturn, and eventually increase the failure potential. In this study, to evaluate the liquefaction potential on the seabed, numerical analysis was conducted using the expanded 2-dimensional numerical wave tank to account for an irregular wave field. In the condition of an irregular wave field, the dynamic wave pressure and water flow velocity acting on the seabed and the surface boundary of the composite breakwater structure were estimated. Simulation results were used as input data in a finite element computer program for elastoplastic seabed response. Simulations evaluated the time and spatial variations in excess pore water pressure, effective stress, and liquefaction potential in the seabed. Additionally, the deformation of the seabed and the displacement of the structure as a function of time were quantitatively evaluated. From the results of the analysis, the liquefaction potential at the seabed in front and rear of the composite breakwater was identified. Since the liquefied seabed particles have no resistance to force, scour potential could increase on the seabed. In addition, the strength decrease of the seabed due to the liquefaction can increase the structural motion and significantly influence the stability of the composite breakwater. Due to limitations of allowable paper length, the studied results were divided into two portions; (I) focusing on the dynamic response of structure, acceleration, deformation of seabed, and (II) focusing on the time variation in excess pore water pressure, liquefaction, effective stress path in the seabed. This paper corresponds to (II).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.160-173
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• 2014

Seabed beneath and near coastal structures may undergo large excess pore water pressure composed of oscillatory and residual components in the case of long durations of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. If liquefaction occurs in the seabed, the structure may sink, overturn, and eventually increase the failure potential. In this study, to evaluate the liquefaction potential on the seabed, numerical analysis was conducted using the expanded 2-dimensional numerical wave tank to account for an irregular wave field. In the condition of an irregular wave field, the dynamic wave pressure and water flow velocity acting on the seabed and the surface boundary of the composite breakwater structure were estimated. Simulation results were used as input data in a finite element computer program for elastoplastic seabed response. Simulations evaluated the time and spatial variations in excess pore water pressure, effective stress, and liquefaction potential in the seabed. Additionally, the deformation of the seabed and the displacement of the structure as a function of time were quantitatively evaluated. From the results of the analysis, the liquefaction potential at the seabed in front and rear of the composite breakwater was identified. Since the liquefied seabed particles have no resistance to force, scour potential could increase on the seabed. In addition, the strength decrease of the seabed due to the liquefaction can increase the structural motion and significantly influence the stability of the composite breakwater. Due to limitations of allowable paper length, the studied results were divided into two portions; (I) focusing on the dynamic response of structure, acceleration, deformation of seabed, and (II) focusing on the time variation in excess pore water pressure, liquefaction, effective stress path in the seabed. This paper corresponds to (I).