• Journal of Korean Orthopaedic Sports Medicine
• /
• v.6 no.2
• /
• pp.99-104
• /
• 2007

Purpose: To research match injuries related to Taekwondo in adolescent athletes and find out preventing injuries. Materials and Methods: We analyzed 162 match injuries of middle and high school athletes, who were surveyed in 2005 and 2006 national tournament. Results: Among 162 match injuries, injuries in foot and hand were the most common and there were 35 cases in serious injuries such as fracture, open dislocation, open fracture of epiphyseal plate and so on. The very fast speed and destructive power of Takwondo athlete can cause open dislocation of great toe and can cause fracture of foot and upper extremity when kicking. Conclusion: We consider that injured athletes need proper treatments and sufficient rest not to accumulate training injuries and match injuries and need to improve mats of stadium, braces for feet and hands and put on braces for elbows to prevent match injuries.

• Fire Science and Engineering
• /
• v.30 no.5
• /
• pp.116-123
• /
• 2016

The quantitative risk assessment methods for thermal failure in targets were studied using fire modeling. To this end, Fire Dynamics Simulator (FDS), as a representative fire model, was used and the probabilities related to thermal damage to an electrical cable were evaluated according to the change in fire area inside a specific compartment. 'The maximum probability of exceeding the damage thresholds' adopted in a conservative point of view and 'the probability of failure' including the time to damage were compared. The probability of failure suggested in the present study could evaluate the quantitative fire risk more realistically, compared to the maximum probability of exceeding the damage thresholds with the assumption that thermal damage occurred the instant the target reached its minimum failure criteria in terms of the surface temperature and heat flux.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5A
• /
• pp.421-431
• /
• 2009

This paper is the study on the verification of structural health monitoring (SHM) algorithm based on the ultrasonic guided wave. An active inspection system using Lamb wave (LW) for SHM was considered. The basic study about the application of this algorithm was performed for detecting the circular notch defect in steel plate. LW testing technique, pitch-catch method, was used for interpretation of circular notch defect with depth of 50% of plate thickness and 7 mm width. Damage characterization takes place by comparing $S_0$ mode sensor signals collected before and after the damage event. By subtracting the signals of both conditions from each other, a scatter signal is produced which can be used for damage localization. The continuous Gabor wavelet transform is used to attain the time between the arrivals of the scatter and sensor signals. A new practical damage monitoring algorithm, based on damage monitoring polygon and pitch-catch method, has been proposed and verified with good accuracy. The possible damage location can be estimated by the average on calculated location points and the damage extent by the standard deviation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.218-226
• /
• 2020

An experimental study was conducted on baseline model updating and damage estimation techniques for the health monitoring of offshore wind turbine tripod substructures. First, a procedure for substructure health monitoring was proposed. An initial baseline model for a scaled model of a tripod substructure was established. A baseline model was updated based on the natural frequencies and the mode shapes measured in the healthy state. A training pattern was then generated using the updated baseline model, and the damage was estimated by inputting the modal parameters measured in the damaged state into the trained neural network. The baseline model could be updated reasonably using the effective fixity model. The damage tests were performed, and the damage locations could be estimated reasonably. In addition, the estimated damage severity also increased as the actual damage severity increased. On the other hand, when the damage severity was relatively small, the corresponding damage location was detected, but it was more difficult to identify than the other cases. Further studies on small damage estimation and stiffness reduction quantification will be needed before the presented method can be used effectively for the health monitoring of tripod substructures.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.2
• /
• pp.153-161
• /
• 2009

A domain/boundary decomposition method is applied for efficient analyses of thermo-elasto-viscoplastic damage and contact problems under the assumption of infinitesimal deformation. For the decomposition of a whole domain and contact boundaries, all the equality constraints on the interface and contact interfaces are restated with simple penalty functional. Therefore, the non-linearity of the problem is localized within finite element matrices in a few subdomains and on contact interfaces. By setting up suitable solution algorithms, the computational efficiency can be improved considerably. The general tendency of the computational efficiency is illustrated with some numerical experiments.

• Proceedings of the KSMRM Conference
• /
• 2003.10a
• /
• pp.42-42
• /
• 2003

목적： 축구는 현재 전세계에서 가장 대중화된 스포츠이며 육체적인 손상이 흔히 발생한다. 여러 손상 부위중에서 하지의 손상이 가장 흔한 것으로 알려져 있고 골, 근육, 건, 인대 등의 다양한 손상이 있을 수 있다. 저자들은 2002년 한국-일본 공동개최 월드컵 경기에 참가했던 8명의 선수에서 나타난, 하지의 다양한 근골격계손상의 분포와 MR소견에 대해 알아보고자 한다.

• Clinical and Experimental Pediatrics
• /
• v.46 no.7
• /
• pp.687-694
• /
• 2003

Purpose : Regeneration and repair after ischemic renal injury appears to be modulated by circulating or locally produced growth factors. This study examined the changes of serum insulin like growth factor(IGF-I) and renal expression of IGF-I and II, vascular endothelial growth factor(VEGF), transforming growth $factor-{\beta}$($TGF-{\beta}$), and connective tissue growth factor(CTGF) during the active regeneration period after acute ischemic injury. Methods : Sera and kidney tissue samples(whole kidney, cortex, outer medullae and inner medullae) were obtained before and after one, three, five and seven days of 40 minutes bilateral renal pedicle clamping. Acute renal failure was assessed by measuring the concentration of serum creatinine. Serum IGF-I level was measured by radioimmunoassay. The mRNA expression in kidney was measured by RT-PCR. The distribution of IGF-I and CTGF was detected by immunohistochemistry. Resuts : Serum IGF-I concentration after one day following acute ischemic renal injury was significantly decreased compared to preischemic value. The mRNA levels of IGF-I, IGF-II, $TGF-{\beta}1$ and VEGF in whole kidney were temporally decreased on day one of ischemic injury. IGF-I and IGF-II expressions in outer medullae were significantly decreased on day one after ischemic injury. $TGF-{\beta}1$, CTGF and VEGF expressions were markedly decreased in medullae after one day of ischemic injury compared to other kidney sections. IGF-I was markedly decreased in cortical tubules on day one of uremic rat. CTGF was markedly increased on tubule within three days of ischemic injury. Conclusion : These findings suggest that IGFs, $TGF-{\beta}1$ and CTGF may involve in the pathogenesis or the recovery from acute ischemic renal injury.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.9
• /
• pp.203-211
• /
• 1999

The research committee for automobile repairs (RCAR), an international body of insurance research centers, has adopted the typical low speed crash test based on an average damage level in crash accidents to estimate the damageability , repairability and safety. The characteristics of body acceleration and the probability of injury are investigated based on damaged components, accelerations of body and injured dummy to analyze damageability and the driver's safety under low speed crash environment. It is found from the experimental results that the probability of head and thorax injuries are very low comparing to the injury criteria of FMVSS No.208. Furthermore, it is suggested that the deployment of airbag may not be necessary at RCAR low speed frontal crash test.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.2
• /
• pp.70-75
• /
• 2000

In this paper a new constitutive model for ductile materials was proposed. This model can describe the material degradation due to the evolution of isotropic damage during elasto-platic deformation. The plastic flow rule was derived under the framework of thermodynamic approach of continuum damage mechanics(CDM) in which plastic strain hardening parameters and isotropic damage were taken as thermodynamic state variables. And the process to determine material constants for constitutive model using an experimental data was presented.

• 월간산업보건
• /
• s.387
• /
• pp.76-79
• /
• 2020

인체면적의 고작 2%를 차지하는 발바닥은 체중의 98%를 지탱하고 있습니다. 그래서인지 근골격계 질환 중에서도 손상이 빈번하게 일어나는 부위가 발목관절인데요. 스포츠 활동뿐만 아니라 일상생활 중에도 손상이 잘 일어나며 한번 손상되면 발목관절 안정성이 떨어지게 되어 재손상이 쉽게 발생합니다. 이에 발목관절 건강을 지킬 수 있는 적절한 예방운동이 꼭 필요합니다.