• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.2
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• pp.95-105
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• 2007

The purpose of this study is to define the effect of taping and icing on muscle fatigue at knee joint of ordinary adult. The 30 adults meeting research standard were chosen to be observed. The period of the research was 9 days and N-K table was used as equipment to measure position sense of knee joint. Heart rate monitor was also used to measure heart beat during both when in comfortable state and in exercises. For the method of this study, error in position sense of knee joint was measured right before fatigue occurs. Then volunteers were to be exercised for 10 minutes in treadmill aiming to raise the heart beat to 90%. If muscle fatigue occurs after the exercise, let the comparative group rest for 20 minutes while applying taping for group 1 and icing for group 2. For the icing, it was applied for 3 minutes followed by 1 minute rest. 5 sets of icing were applied on thighs and calf each, Then error of position sense of knee joint was measured same way it was done before muscle fatigue. As the result, there were similar differences among comparative group(p<.05), group 1 and group 2 before the muscle fatigue and after the muscle fatigue. There were similar differences in comparative group with muscle fatigue, group 1 and group 2 as the result of one-way ANOVA and with further examination, similar differences were only found in between comparative group and group 2(p<.05). With the result, we can see there wasn't clear effect of rest, icing or taping, however, group 2 with icing showed better condition compared to comparative group who have rested without any application.

• Journal of Applied Reliability
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• v.17 no.1
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• pp.50-57
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• 2017

Purpose : This paper is a comparative analysis results of the fatigue test for dental implants and accelerated life test by using a static type loading device commonly used in Korea and a dynamic type loading device (universal-joint) recommended by FDA. Methods : Fatigue tests of dental implant is based on ISO 14801 and classified into static load test and dynamic load test. The tests were carried out on three test specimens by four load stress steps under each loading device. For analysis on failure mode such as crack, fracture and permanent deformation of test specimens, we used X-ray three-dimensional computed tomography on test specimens before and after the fatigue tests. The design of the accelerated life test was based on the analysis results of the fatigue life data obtained from the dynamic load test and the statistical analysis software (Minitab ver.15) was used to analyze the appropriate life distribution. Results : As a result of the fatigue tests and the accelerated life tests at same acceleration condition under each test method, the fatigue life under the dynamic type loading device (universal-joint) was shorter than when static type loading device was applied. Conclusion : This paper can be used as a reference when the universal-joint type loading device for implants fatigue test is applied as ISO 14801.

• Explosives and Blasting
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• v.22 no.3
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• pp.1-12
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• 2004

In bench blasting, rock fragmentation is one of the most important factors determining productivity. Rock fragmentation could be affected by various conditions and these were hewn that rock joint conditions and in-situ block sizes were the biggest effect on it. This research is focused on what or how to influence on rock fragmentation according to relation between blasting conditions and the in-situ rock conditions such as rock joint conditions and in-situ block size. Field measurements were carried out in 3 open pit limestone mines, where in-situ rock conditions and blasting conditions were fully investigated. The results show that the parameters interact with blasting conditions complicatedly and especially in-situ block size has bigger effects. Dip direction of major joint set also can affect on fragmentation. Mean fragment size become smallest when dip direction of major joint set is about $30^{\circ}$ with the bench direction. The reason is considered to be come from difference of propagation paths of elastic wave.

• Composites Research
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• v.28 no.6
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• pp.348-355
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• 2015

NDT (Non Destructive Test) of the adhesive joints is very important because their strengths have greatly affected by the worker's skill and environmental condition. Recently, the electric impedance method in which 1-2 wt% CNT was dispersed in the adhesive and the electric resistance of the adhesive joint was measured was suggested for the defect detection of the adhesive joint. The uniform dispersion of CNT in the electric impedance method is very important to make a constant electric resistance of the adhesive joint and the accuracy of defect detection depends on the uniform dispersion. In this paper, the adhesive joints in which CNT was dispersed in the adhesive by the four dispersion methods were made and their electric resistance were measured. The pre-process and evaporation process of CNT using the ultrasonic method and agitation method was used and the effective dispersion method was suggested. Also, the criteria to evaluate the dispersivity was proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.792-798
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• 2015

Joint angle generally can be measured to check the recovery process in rehabilitation field. This paper suggests to measure joint angle with Infrared sensor based on triangulation principle. We performed various experiments to find the optimal condition of the sensor’s attached distance, height, and angle. The results were compared with commercial goniometer for accuracy. The proposed infrared joint angle sensor can be effectively used in rehabilitation and sport science fields.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.47-55
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• 2013

PURPOSES : The purpose of this study is to investigate the optimal joint positions which can minimize distresses of concrete pavement containing box culvert with horizontally skewed angles. METHODS : The concrete pavement containing the box culvert with different skewed angles and soil cover depths was modeled by 3 dimensional finite element method. The contact boundary condition was used between concrete and soil structures in addition to the nonlinear material property of soil in the finite element model. A dynamic analysis was performed by applying the self weight of pavement, negative temperature gradient of slab, and moving vehicle load simultaneously. RESULTS : In case of zero skewed angle ($0^{\circ}$), the maximum tensile stress of slab was the lowest when the joint was positioned directly over side of box culvert. In case there was a skewed angle, the maximum tensile stress of slab was the lowest when the joint passed the intersection between side of the box culvert and longitudinal centerline of slab. The magnitude of the maximum tensile stress converged to a constant value regardless the joint position from 3m of soil cover depth at all of the horizontally skewed angles. CONCLUSIONS : More reasonable and accurate design of the concrete pavement containing the box culvert can be possible based on the research results.

• The Journal of Korean Physical Therapy
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• v.28 no.6
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• pp.381-384
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• 2016

Purpose: Previous studies reported changes in the first metatarsophalangeal (MTP) joint angle in relation with and without weight bearing, but it is unclear whether sesamoid bone of the great toe changes in weight bearing conditions particularly in subjects with hallux valgus (HV). To investigate how weight bearing conditions can affect the position of the medial sesamoid bone (MSB), first MTP joint angle, and second intermetatarsal angle (IMA) in the recruited subjects. Methods: Subjects were recruited 24 with HV and 21 without HV in study. X-rays were taken in the weight bearing and non-weight bearing conditions. The distance of the MSB, first MTP joint angle, and second IMA were measured from the radiographs. Data were analyzed by paired and Independent t-test. The statistical significance level was p<0.05. Results: In both groups, the first MTP joint angles and the distance of the MSB were significantly smaller, while the second IMA was significantly greater in the weight bearing condition. The difference in the distance of the MSB between the two postures was significantly greater in the group with HV. Conclusion: Weight bearing can affect the first MTP joint angle, second IMA, and position of the MSB; the change in the position of the MSB in weight bearing was greater in the group with hallux valgus. The difference in these variables between weight bearing and non-weight bearing conditions may be considered when measuring HV.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.53-61
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• 2019

PURPOSE: This study examined the dynamic range of motion (ROM) of the hip, knee, and ankle joint when wearing different shoe sole lifts, as well as the limb asymmetry of the range according to the leg length discrepancy (LLD) during normal speed walking. METHODS: The participants were 40 healthy adults. A motion analysis system was used to collect kinematic ROM data. The participants had 40 markers attached to their lower extremities and were asked to walk on a 6 m walkway, under three different shoe lift conditions (without an insole, 1 cm insole, and 2 cm insole). Visual3D professional software was used to coordinate kinematic ROM data. RESULTS: Most of the ROM variables of the short limbs were similar under each insole lift condition (p>.05). In contrast, when wearing a shoe with a 2 cm insole lift, the long limbs showed significant increases in flexion and extension of the knee joint as well as; plantarflexion, dorsiflexion, pronation, eversion, and inversion of the ankle joint (p<.05). Of the shoes with the insole lifts, significant differences in all ROM variables were observed between the left and right knees, except for the knee internal rotation (p<.05). CONCLUSION: As the insole lift was increased, more ROM differences were observed between the left and right limbs, and the asymmetry of the bilateral lower limbs increased. Therefore, appropriate interventions for LLD are needed because an artificial mild LLD of less than 2.0 cm could lead to a range of musculoskeletal problems of the lower extremities, such as knee and ankle osteoarthritis.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.259-266
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• 2018

In the work, the carbonation behavior and strength characteristics in cold-joint concrete are evaluated for OPC(Ordinary Portland Cement) and GGBFS(Ground Granulated Blast Furnace Slag)concrete considering three levels of curing age (28, 91 and 365 days). The compressive strength in GGBFS concrete is level of 86% of OPC concrete at the 91 days of curing period, but is level of 107% at 365 curing days due to hydration reaction. Carbonation velocities in both OPC and GGBFS concrete significantly decease after 91 curing days. The effect of cold joint on carbonation is evaluated to be small in GGBFS concrete. The increasing ratios of carbonation velocity in cold joint are 1.06 and 1.33 for 28-day and 365-day curing condition, respectively. However they decreases to 1.08 and 1.04 for GGBFS concrete for the same curing conditions.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.199-205
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• 2018

Objective: The purpose of this study was to examine the effect of increase in barbell weight on closely related variable to the anterior cruciate ligament (ACL) injury which are knee joint kinematics, joint load, joint moment, and maximum load attainment point during snatch of the weight lifting. Method: The subjects of the study were 10 male Korean national weight lifting athletes (69 kg 5, 77 kg 5; age: $21.80{\pm}3.91yrs.$, height: $168.00{\pm}4.06cm$, weight: $75.00{\pm}4.02kg$, career: $7.8{\pm}3.99yrs.$, snatch records: $168{\pm}4.06kg$). The weight of the barbell during the snatch operation was set at 70%, 75% and 80% of the highest records for each subject studied. Results: The result obtained from the one-way repeated measure ANOVA are as follows: With increased barbell weight, the extension moment of the left knee joint was higher in the 80% condition than the 70% (p<.001). However, other variables were not statistically significant difference. According to the factor analysis of the variables related to maximum load attainment point of the ACL major injury variables, the first sub-factor was the internal shear force, the posterior shear force, the abduction moment, and the muscle activity of the VL. The second sub-factor was the extension moment of the knee joint, compressive force, adduction moment, and the third sub-factor was the muscle activity of BF. Conclusion: These results indicate that the possibility of ACL injury can be lowered when performing a stable snatch movement.