• Journal of Korean Orthopaedic Sports Medicine
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• v.11 no.1
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• pp.66-68
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• 2012

Lumbar disc herniation in the adolescent is rare. The clinical features of adolescent lumbar disc herniation are typically different from those of adults. Many adolescent with that disease may be misdiagnosed as minor trauma, muscle sprain, tight hamstrings or scoliosis. Published series reiterate that adolescents, as opposed to adults, do not respond well to conservative treatment. In adolescent lumbar disc herniation with hamstring tightness, the neurologic defects are improved shortly after, discectomy, but the hamstring tightness continue and remain even after 1 year. Earlier discectomy and adjunct postsurgical conservative measures can provide a greater opportunity for correction and stabilization of scoliotic posture. We here report on a case of adolescent lumbar disc herniation that was misdiagnosed by knee injury during 2 years. After posterior partial discectomy, the hamstring tightness and scoliosis was disappeared without complication.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.150-155
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• 2012

One of the primary purposes of tugs is for the towing of other ships in salvage operations. In order to conduct such a task safely, the tug should be capable of generating the appropriate towing forces. Therefore the prediction of resistance against a towed ship during towing operation is a very important and essential procedure. This paper studies the ship resistance calculation program to predict towing force. The calculation program consists of the functions that calculate basic hull resistance in calm water, added resistance due to wind, drifting, hull roughness, waves, shallow water and currents. All predictions are calculated by statistical and empirical methods by graph or formula. The calculation results made by this program are compared with the results from the U.S. Navy's Towing Manual. These results confirm that this computer program is quite capable of appropriately predicting the resistance of damaged ships.

• Journal of Trauma and Injury
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• v.28 no.4
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• pp.284-291
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• 2015

The aim of this study is to present a nonoperative treatment for abdominal injuries in patients with multiple traumas and to discuss the role of metropolitan tertiary hospital, non-regional trauma centers. We collected data from patients with multiple traumas including abdominal injuries from 2009 to 2014. Patient characteristics, associated injuries, short-term outcomes and departments that managed the patients overall were analyzed. Based on treatment modalities for abdominal injury, patients were divided into two groups: the operative treatment group and the nonoperative treatment group. We compared differences in patient characteristics, injury mechanisms, initial vital signs, detailed injury types, lengths of hospital and ICU stays. Of the 167 patients with multiple traumas, abdominal injuries were found in 57 patients. The injury mechanism for 44 patients (77.2%) was traffic accidents, and associated extra-abdominal injuries were shown in 45 patients (78.9%). The mean lengths of hospital and ICU stays for the 57 patients were 36.4 days and 8.3 days, respectively. The in-hospital mortality rate was 8.8%. Ten patients (17.5%) were treated operatively, and 47 patients (82.5%) were treated nonoperatively. Among the 47 patients in the nonoperative treatment group, 17 patients received embolization, and 3 patients underwent a percutaneous drainage procedure. Operative treatments were used more in patients with injuries to the pancreas and bowel. No patient required additional surgery or died due to the failure of nonoperative treatment. No differences in the clinical characteristics except for the detailed injury type were observed between the two groups. In appropriately selected patients with multiple traumas including abdominal injuries, nonoperative treatment is a safe and feasible. For rapid and accurate managements of these patients, well-trained trauma surgeons who can manage problems with the various systems in the human body and who can decide whether nonoperative treatment is appropriate or not are required.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.277-280
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• 2008

Reinforced concrete structures have an excellent durability under a good construction and continuous maintenance. But reinforced concrete construction is influenced by atmospheric phenomena and it is creating a deterioration. One of the deterioration cause on concrete is a freezing and thawing action. Freezing and thawing leads to the reduction in concrete durability by the cracking or surface spalling. If we are carried out freezing and thawing, deterioration of reinforced concrete construction will be reduction. Therefore, this study was performed to investigate the flexural behavior of reinforced concrete beams exposed to freezing and thawing cycles. Thee presence of damage and cycles were considered as variablees in this study.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.372-380
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• 2007

Surface damage due to subsidence is an inevitable consequence of underground mining, which may be immediate or delayed for many years. The surface damage due to abandoned underground mine is observed to be two subsidence types such as simple sinkhole or trough formation to a large scale sliding of the ground from with in the subsided area. An evaluation of the risk of a subsidence occurrence is vital in the areas affected by mining subsidence. For a subsidence prediction or a risk evaluation, there has been used various methods using empirical models, profile functions, influence functions and numerical models. In this study, a simple but efficient evaluation method of subsidence hazard is suggested, which is based on a diffusion theory and uses just information about geometry of caving and topography. The diffusion model has an analogous relationship with granular model which can explain a mechanism of subsidence. The diffusion model is applied for the evaluation of subsidence hazard in abandoned metal and coal mines. The model is found to be a simple but efficient tool because it needs information of geometry of caving and gangway and the topography.

• Korean Journal of Cognitive Science
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• v.21 no.4
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• pp.603-625
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• 2010

Neural representation of a visual object is distributed across visual cortex and overlapped with those of many other objects. Thus repeating an object facilitates the recognition of the object while it impairs the recognition of other objects. These effects are called repetition priming and antipriming, respectively. Two experiments investigated a new phenomenon of repetition antipriming, in which a repeated object itself is antiprimed. The learning stage presented object pictures which were degraded at various levels. Participants determined how recognizable each object was. Then, the test stage presented the intact version of the object pictures and made participants to perform a categorization task. Both Experiment 1 and 2 found that the processing of the objects that had been recognized were facilitated (repetition priming) while the processing of the objects that had been perceptually ambiguous were impaired (repetition antipriming). These findings suggest that experiencing a perceptually ambiguous object might enhance the connection between feature-level representations and multiple object-level representations, which impairs the subsequent recognition of the repeated object.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.225-232
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• 2017

Several maintenance issues related to cavitation erosion and fatigue cracks in the water turbine subcomponents of pumped-storage plants, such as a runner and a draft tube, have been reported in the past. Generally, the pumped-storage plants provide ancillary services, such as black-start and system stabilization. The ancillary services are responsible for cyclic low opening operation of the guide vanes. It has been empirically established that this low opening operation further damages the water turbine subcomponents. In this study, the acceleration effect of the low opening operation on the cavitation erosion and fatigue of the water turbine is quantitatively assessed through finite element flow analysis, finite element stress analysis, and fatigue analysis. As a result of the assessment, it is identified that the cavitation potential increases and the turbine efficiency decreases with a decrease in the opening of the guide vane. Also, the low opening operation has an insignificant effect on the fatigue even though it increases the maximum stress values at the runner blade roots.

• Journal of Chest Surgery
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• v.39 no.11 s.268
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• pp.868-871
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• 2006

Nuss operation as a method for correction of pectus excavatum is safe and satisfactory, but its complication presents pneumothorax, displaced bar, wound infection, pericarditis, pleural effusion, hemothorax, cardiac injury etc. We report a rare case of acute ascending aortic rupture after displaced and adhered Nuss bar removal. The patient was a 30-years old man who received Nuss operation 3 years ago. Nuss bar was removed without resistance but massively bled at both operation wound, so immediately femoro-femoral CPB and median sternotomy was done and repaired proximal aortic arch under deep hypothermic total circulatory arrest. The patient was discharged without complication at postoperative 13 day.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.87-94
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• 1999

Empirical design is still used to avoid a structural damage because impact phenomenon and structural behaviour due to wave impact load can not examined accurately. The damage due to wave impact load is largely affected by impact pressure impulse and impact load area. The objective of this study is, as the second step, to develop an efficient scantling program of bow flare structure, and to predict its impact load area by comparing maximum dented deformations at center of idealized panel structure model of bow flare structure of 300k DWT VLCC using LS/DYNA3D code, which will be used for its verification of dynamic structural analysis, as the next step. Through this study, the impact load area was estimated as $1.5s{\times}1.5s$ stiffener space(s) in the case of panel with stiffeners and as $2.5s{\times}2.5s$, with stringers, under impact pressure curve with peak height 6.5MPa, tail height 1.0MPa, and duration time 5.0msec.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.537-542
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• 2005

Dentofacial trauma can result in tooth fracture, avulsion, facial bone fracture. The Unites states and Japan mandated the use of mouthguards for contact sports. But, Korean didn't. Mouthguards divided into ready-made type and custom-made type. Mouthguards protect the lips, intraoral soft tissues, teeth and provide the mandible with resilient support to prevent jaw fracture and dislocations. Sports-related accidents have been reported to be one of the most common causes of dentofacial trauma. Sports trauma of involving teeth with incomplete root formation cause long chair time, multiple visit, economic considerations, additional dental services. So, mouthguards can offer considerable protection against sports-related trauma.