• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.99-104
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• 2010

It is a frequent occurrence in urban traffic - a low-speed collision in which one vehicle hits the back of another. The vehicles often sustain expensive damage. Bumpers can reduce this damage, but only line up so the initial contact in an impact is bumper to bumper. Then the bumpers on the colliding vehicles have to absorb the crash energy, keeping damage away from expensive sheet metal, lights, and other components. In real world accidents, Bumper mismatches in crashes are increasing, and the resulting repair costs from low-speed collisions are escalating. In this study, we investigated the bumper rail height and analyzed their effects on repair cost. Futhermore, Our 16kph front-into-rear crash tests demonstrates bumper mismatch problem.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.35-39
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• 1997

스키는 겨울철에 하는 옥외 스포츠로서, 때로는 -30 .deg. C 정도의 저온이나 강풍이 부는 한냉 환경하에서 행하여지는 경우도 있다. 이러한 한냉환경은 신체기능을 저하시켜서 불쾌감을 증가시키므로 의복의 중요성이 더욱 강조된다. 인간과 환경 사이에 놓여 있는 스키웨어는 그 시대의 세련된 패션성이 요구될 뿐만 아니라 운동기능성, 안전성, 내구성 그리고 쾌적성을 구비하지 않으면 안된다. 따라서 환경이 인체에 미치는 영향이나 인간의 생리적 메커니즘을 인식하므로서 비로서 쾌적한 스키웨어를 만들 수 있는 것이다. 다양한 형태의 삶을 추구하는 현대인들의 관심은 점차 여가 시간의 건전한 활용 및 스포츠에 집중 되고 있다. 이러한 사회적인 경향에 발 맞추어 신소재의 스키웨어의 개발이 활발히 진행되고 있다. 예컨데 태양 광선을 흡수하는 세라믹 투입의 신소재의 개발과 체내에서 방출하는 열을 가능한 발산하지 않는, 두 가 지 기능을 합한 축열보온 소재의 스키웨어와 또 탁월한 방수. 방풍의 효과와 운동시 발생되는 수분. 열 배출 을 위한 투습의 능력이 있고 보온의 효과가 매우 높은 힐스포(HEALSPO) 코팅 소재를 사용한 스키웨어도 개발 되고 있다. 그리고 보온성과 심리적 만족감을 위한 원피스, 투피스, 쓰리피스 타입의 디자인 개발도 진행되 고 있다. 본 연구에서는 한냉하 운동시의 축열보온 소재 및 힐스포 소재와 같은 특수소재 스키웨어가 인 체에 미치는 영향을 다른 일반 소재와 비교 고찰하고, 스키웨어의 디자인에 대한 보온성의 효과를 검토하기 위하여, 저온환경에서의 피험자의 온열생리학적 반응을 측정하였다.한 신장/근력 팀의 경우보다 높은 에너지 소비량과 심박수를 보였다.찰한 결과, 세포독성 및 염색체 이상을 유발하지 않았다. 또한 동물약품으로 사용되는 치료용량 및 투약방법에 근거하여 10mg/kg 및 5, 2.5mg/kg을 1일 1회씩 4회 투여한 군에서도 암수에 상관없이 전 농도 군에서 염색체이상을 나타내지 않아 유전독성을 나타내지 않음을 관찰하였다. 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.mance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.78-85
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• 2011

Purpose: To evaluate the usefulness of computerized tomography (CT) for the diagnosis and the fragment fixation of anteroinferior tibiofibular ligament avulsion fracture in ankle fracture. Materials and Methods: We retrospectively studied 108 patients with an ankle fracture who had been checked with plain radiographs and CT from July 2006 to July 2010. They were divided into two groups; patients with (19 patients) and without (89 patients) an avulsion fracture of anteroinferior tibiofibular ligament. The two groups were evaluated with Lauge-Hansen classification, the energy of trauma, and the radiologic indices for syndesmotic injury, and were compared each other. Average follow up periods of two groups were 25 and 23 months each. Those who were unstable at stress test during surgery were divided into fragment fixation of anteroinferior tibiofibular ligament avulsion fracture group (8 patients) and transfixation one (11 patients) according to treatment method. Clinical and radiological results at last follow up were also compared. Results: Fourteen avulsion fractures of anteroinferior tibiofibular ligament were diagnosed by CT only. Incidences of pronation-external rotation injury, high energy trauma, positive radiologic indices for syndesmotic injury were significantly higher in patients with an avulsion fracture of anteroinferior tibiofibular ligament than those without it. Clinical and radiological results were satisfactory in both groups at last follow up, and were not significantly different between them. Conclusion: In patients who have an ankle fracture by pronation-external rotation injury, high energy trauma, or with positive radiologic indices for syndesmotic injury, CT is useful for diagnosis of an avulsion fracture of anteroinferior tibiofibular ligament. Fragment fixation of anteroinferior tibiofibular ligament avulsion fracture is a useful treatment option for syndesmotic injury.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.247-254
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• 2001

There is a growing tendency for injury and it is essential to know about the epidemiology of the injured teeth for proper and timely treatment. Through empirical data analysis of 120 children who came to pediatric dentistry of Kangnung National University Dental Hospital, this study purposes to give an understanding about the injury and analyzes the frequency by children's sex and age, the number of injured teeth according to the area in the mouth, the types of injury, causes and places of injury, the frequency occurred by month and hour, the position of injured teeth, and the elapse of time. The main findings of this study are summarized as follows: 1. The frequency analysis by sex shows that the rate of boys is more likely to be higher than girls(1.6:1). 2. The frequency analysis by age shows that the ratio of children between aged 2~4 and 8~10 are high. 3. The number of injured teeth is generally one(51.7%). 4. Periodontal tissue injury is the main cause for the primary teeth. In case of permanent teeth, the ratio of hard tissue injury which is much increased than the case of the primary teeth, is similar to that of periodontal tissue injury. 5. The main cause of injury is fall for both dentition; In case of permanent dentition, the ratio of injury by sports is increased. 6. The place of injury for primary teeth is mainly home(38.8%); Street and school for permanent teeth(42.5% and 35%, respectively). 7. The frequency by month shows that the injury is most frequently occurred in July. 8. The frequency analysis by hour shows that injury for primary teeth mostly happens in the morning; in the afternoon for permanent teeth. 9. The position of injured teeth according to the area in the mouth is mainly maxilla anterior in both case of primary and permanent teeth and especially the ratio of central incisors is high, 10. More than half(59.2%) of patients came to the hospital within one day and the seriously injured were likely to come within one day than the slightly injured.

• Journal of Korean Orthopaedic Sports Medicine
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• v.7 no.1
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• pp.50-54
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• 2008

Purpose: In most cases, the main cause of chest or back pain during playing golf is rib fractures. This kind of rib fractures can be easily overlooked in plain radiographs. The purpose of this article is to clarify the value of the ultrasound in detecting rib fractures. Materials and Methods: We compared the findings of chest-X rays (anteroposterior, left or right lateral, both oblique view) with those of the ultrasound in 56 patients between the ages of 20th & 60th who were diagnosed rib fractures. Their chief complaints were chest or back pain which developed during playing golf. The results were analyzed statistically. Results: Among 56 cases of rib fractures, 34 cases were diagnosed with initial X-rays. 51 cases were diagnosed with ultrasound. The sensitivity of radiograph and ultrasound were 60.71% & 91.07%, respectively. Dignosis was ultrasound with statical significance whereas radiography did not(p=0.0004). Conclusion: It was concluded that ultrasound is a valuable tool in the diagnosis of the rib fractures which were undetected with X-rays during playing golf.

• Journal of Korean Orthopaedic Sports Medicine
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• v.6 no.1
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• pp.50-56
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• 2007

Purpose: To evaluate the aspect of occurrence and transition of the elbow injuries in baseball players from childhood to adult. Materials and Methods: We had a survey and took the simple X-ray from the anteroposterior view and the lateral view of both elbows for subjects of total 320 baseball players. - each of 80 players in elementary school, middle school, high school, and professional baseball players between January and December in 2004. Results: The region of pain and the bony changes in elbow were the most frequent in medial side from all the groups of players. Especially, hypertrophy of medial epicondyle were the most numerous. As baseball players got older, the radiological changes of elbow were increased. The bony changes were found out 52 cases (65%) of the elementary school players, 66 cases (82%) of the middle school players, 68 cases (85%) of the high school players and 70 cases (88%) of the professional players out of the total 320 baseball players. Conclusion: The bony changes of the elbow in baseball players got frequent as they were getting older and increased in comparison with past.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.49-54
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• 2002

Purpose : To analyze the clinical results of treatment for the osteochondritis dissecans of femoral condyle by age, the type of lesion and method of treatment. Methods : From March 1991 to February 2000, 17 patients (20 cases) with osteochondritis dissecans of the femoral condyle were followed up over 1 year. Three patients had bilateral lesion. There were 12 cases with trauma history (9 cases with sports injury and 3 cases with direct trauma). The initial symptoms were pain, clicking, locking, giving way in the order of frequency, pain was revealed in all cases. Clinical evaluation of IKDC and Hughston method were used for subjective and objective function. Results : The number of male patient was 12, and the mean age was 19.8 year old (11$\~$50). The location of the lesion was 14 cases in medial femoral condyle and 6 cases in lateral femoral condyle. The arthroscopic findings of the lesion in 15 cases were as follows, early separation in 6 cases, partially detachment in 4 cases, and crators and complete detachment in 5 cases. 5 cases were treated with mutiple drilling and 5 cases with Herbert screw fixation, 3 cases with Herbert screw fixation and bone graft. In early stage, 7 cases were treated with conservative method. In the grading of Hughston score, 6 cases were graded as excellent, 9 cases as good, 15 cases were graded as good to excellent. Based on the IKDC scale, 1 case was graded as normal, 6 as nearly normal, and 10 as abnormal. Conclusions : The trauma seemed to be important factor in occurrence of osteochondritis dissecans of the femoral condyle. The clinical results of juvenile period showed better than adolescence and adult period, it is necessary to detect the lesion as soon as possible. The result of subjective evaluation was worse than the Hughston evaluation. It was caused by limiting involvement of sports activity and limited activity in the adolescence.

• Journal of Yeungnam Medical Science
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• v.9 no.2
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• pp.302-311
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• 1992

Talus is a important structure of the ankle joint and its function is critical for ambulation and weight bearing. The talus fracture is rare, but the complications of fracture and dislocation are serious and resulting in avascular necrosis, osteoarthritis. So its treatment is carefully considered at initial status. Authors reviewed 11 cases of fracture and dislocation of the talus treated at Yeungnam university hospital from 1984 to 1991. The longest follow up was 8 years and shortest, 1 year. The results were as follows. 1. There were all males, the average age was 30 years old. 2. The most common cause was fall down(8 cases), and next traffic accident(2cases), sports injury(1 case). 3. According to Marti-Weber classification, 1 cases was type I, 1 in type II, 4 in type III and 5 in type IV. 4. The method of treatment were open reduction and internal fixation in 6 cases, the others were closed reduction in 5 cases. 5. Final results(by Hawkins grading system) were as follows, 3 cases were excellent, 4 cases were good, 1 case was fair and 3 cases were poor. 6. Complications were AVN in 2 cases, degenerative arthritis in 8 cases, malunion in 1 case. 7. The range of motion of the ankle joint was relatively preserved(74%), but in the subtalar joint it was decreased(43%).

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.1
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• pp.81-86
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• 2004

Objectives: To assess the functional outcome of Bankart repair and rotator cuff repair using miniopen technique in patients with recurrent shoulder dislocation(8 cases) with rotator cuff tears and Bankart lesion of over 40 years. Materials and Methods: From May 1991 to January 2002, twenty two patients were available to participate in the study. Mean age was 52 years old(41-67), Follow-up evaluations averaged 50.5months(10-147). Results: The patients(22 cases) were divided into two groups. Group 1: with recurrent shoulder dislocation(8 cases) with rotator cuff tears and Bankart lesion in patients over 40 years old. Group 2: without Bankart lesion(14 cases). In Group 1, mean average of forward flexion and abduction improved from 122 degrees to 154 degrees at the final follow-up and from 115 degrees to 161 degrees respectively. In terms of University of Pennsylvania patient self-assessment of pain score and VAS, scores improved from 11.0 to 5.5 and from 5.4 to 2.5 respectively. In terms of UCLA score & Constant score, scores also improved from 20.2 to 29.6 and from 48.6 to 69.0 respectively. Functional outcome of Group 1: two patients with excellent, four patients with good, and two patients with fair. Functional outcome of Group 2: two patients with excellent, six patients with good, five patients with fair, and one patient with poor. But they had no statistical significance between the two groups. All cases were improved shoulder pain at the final follow up. And six patients were satisfied with the outcome of shoulder function. Conclusions: This study demonstrates the effectiveness of Bankart repair and rotator cuff repair using miniopen technique in patients with recurrent shoulder dislocation(8 cases) with tears of rotator cuff and Bankart lesion older than 40 years. We recommend Bankart repair and rotator cuff repair at the same time.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.43-48
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• 2002

Purpose : We evaluated radiographic changes and clinical manifestations of the elbow joint to identify the effects of the throwing between dominant and non-dominant arms. Materials and Methods : A hundred and five little leaguer’s baseball player in 5 elementary school and 2 middle school were evaluated for clinical symptoms and radiographic changes about elbow joint. Mean age was 12 years old and average periods of exercise were 32 months. Elbow functions were evaluated using ASES standardized assessment form and radiographic changes of medial epicondyle were examinated for enlargement, separation of the apophyses, fragmentation and irregularity. Results : Thirty seven players (35$\%$) were complained pain with throwing and the average score was 4.8 using visual analog scale. There were no significant differences in range of motion except flexion angle, valgus angle, and strength between dominant arm and non-dominant arm. Valgus laxity was more prominent in dominant arm. Ulnohumeral tenderness, radiocapitellar tenderness and medial flexor origin tenderness were in 18, 6, and 17 cases respectively in dominant arm. Medial epicondyle was enlarged in dominant arm with 13.0 by 6.3 mm compared to non-dominant arm with 11.7 by 6.1 mm. Apophyseal separation was 0.8 mm in dominant arm and 0.5 mm in non-dominant arm. Fragmentation and irregularity were 14 (13$\%$) and 25 (24$\%$) cases respectively in dominant arm. Conclusion : In little league baseball player, it needs usage of ball and bat with appropriate weight, and careful conditioning programs through throwing exercise in order to avoid elbow injuries.