• Archives of Plastic Surgery
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• v.33 no.5
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• pp.531-535
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• 2006

Purpose: To report our experience of retro-angular flap for reconstruction of the midface defect. The midface, including nose, lower eyelid, and intercanthal area, is the very prominent area of face. Also midface is more vulnerable to trauma and skin cancer and defect of mid face of highly perceptible. Reconstruction of mid face is difficult because of complexity of anatomy and functions. Following factors should be considered in reconstructive prcedure of midface. First, multiple procedure may need for complete the reconstruction of mid face defect. Second, secondary reconstructive surgeries such as flap rotation or skin graft may need for donor site morbidity. Third, the color, texture and thickness of the skin used are not always complacency. Methods: 8 cases of the midface defects (3 cases of lower eyelid, 1 case of intercanthal area, and 4 cases of nose) from skin cancer were reconstructed with retroangular flap from March 2004 to August 2005. Results: Satisfactory result were obtained in color, texture and donor site scar. There was no major complication such as wound disruption, hematoma, and atrophy of flap. But partial necrosis of flap and bulkiness were observed one case in each. Retroangular flap is simple procedure that can be preceded in one stage under local anesthesia closing primary wound closure. It will leave less visible donor scar, acceptable color, texture and thickness of the skin. Conclusions: The retro-angular flap could be suggested as a safe and effective method for midface reconstruction.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.199-204
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• 2005

The nose is the most prominent area of the face, therefore susceptible to trauma and skin cancer. When small sized defect is in nasal tip, it results in disturbance of the facial harmony even if replantation, composite graft, skin graft or median forehead flap has been used for the reconstruction. So it is needed that the best method reconstruction is performed according to the degree of defect or deformity. And at the same time the physiology and anatomy of nose were clarified and its aesthetic subunits were employed. How can we cover the about 3 cm sized nasal defect in nasal tip with cartilage exposure? At first, we can think forehead island flap is most appropriate. We performed 7 cases of the forehead island flap for reconstruction of the defect in nasal tip(4 cases: cancer, 3 cases: trauma) from March, 2001 to August, 2004. This result was satisfactory in the point of texture, color, donor scar, and there were no complication such as wound disruption, infection, flap atrophy, and hematoma. The advantages of forehead island flap are: 1) No injury of deep vessel and nerve, 2) control of shape and volume, 3) Short operation time, 4) primary closure of donor site, 5) one stage operation. Also, forehead island flap can cover the defect in nose where skin graft and local flap can not cover. But, operator always must take care for flap congestion and donor site scar. We thought forehead island flap is one of the best option of reconstruction of nasal tip defect.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.175-182
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• 2005

Skull base tumors have been determined inoperable because it is difficult to accurately diagnose the extent of the involvement and to approach and excise the tumor safely. However, recently, the advent of sophisticated diagnostic tools such as computed tomography and magnetic resonance imaging as well as the craniofacial and neurosurgical advanced techniques enabled an accurate determination of operative plans and safe approach for tumor excision. Resection of these tumors may sometimes result in massive and complex extirpation defects that are not amenable to local tissue closure. The purpose of this study is to analyze experiences of skull base reconstruction and to evaluate long term survival rate and complications. All cranial base reconstructions performed from July 1993 to September 2000 at Department of Plastic and Reconstructive Surgery of the Seoul National University Hospital were observed. The medical records were reviewed and analysed to assess the location of defects, reconstruction method, existence of the dural repair, history of preoperative radiotherapy and chemotherapy, complications and causes of death of the expired patients. There were 12 cases in region II, 8 cases in region I and 1 case in region III according to the Irish classification of skull base. Cranioplasty was performed in 4 patients with a bone graft and microvascular free tissue transfer was selected in 17 patients to reconstruct the cranial base and/or mid-facial defects. Among them, 11 cases were reconstructed with a rectus abdominis musculocutaneous free flap, 2 with a latissimus dorsi muscluocutaneous free flap, 1 with a fibular osteocutaneous free flap, 2 with a scapular osteocutaneous free flap, and 1 with a forearm fasciocutaneous free flap, respectively. During over 3 years follow-up, 5 patients were expired and 8 lesions were relapsed. Infection(3 cases) and partial flap loss(2 cases) were the main complications and multiorgan failure(3 cases) by cancer metastasis and sepsis(2 cases) were causes of death. Statistically 4-years survival rate was 68%. A large complex defects were successfully reconstructed by one-stage operation and, the functional results were also satisfactory with acceptable survival rates.

• Journal of Chest Surgery
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• v.46 no.2
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• pp.93-97
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• 2013

Background: Minimally invasive cardiac surgery has emerged as an alternative to conventional open surgery. This report reviews our experience with atrial septal defect using the da VinciTM surgical robot system. Materials and Methods: This retrospective study included 50 consecutive patients who underwent atrial septal defect repair using the da VinciTM surgical robot system between October 2007 and May 2011. Among these, 13 patients (26%) were approached through a totally endoscopic approach and the others by mini-thoracotomy. Nineteen patients had concomitant procedures including tricuspid annuloplasty (n=10), mitral valvuloplasty (n=9), and maze procedure (n=4). The mean follow-up duration was $16.9{\pm}10.4$ months. Results: No remnant interatrial shunt was detected by intraoperative or postoperative echocardiography. The atrial septal defects were mainly repaired by Gore-Tex patch closure (80%). There was no operative mortality or serious surgical complications. The aortic cross clamping time and cardiopulmonary bypass time were $74.1{\pm}32.2$ and $157.6{\pm}49.7$ minutes, respectively. The postoperative hospital stay was $5.5{\pm}3.3$ days. Conclusion: The atrial septal defect repair with concomitant procedures like mitral valve repair or tricuspid valve repair using the da VinciTM system is a feasible method. In addition, in selected patients, complete port access can be helpful for better cosmetic results and less musculoskeletal injury.

• Annals of Clinical Neurophysiology
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• v.3 no.1
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• pp.26-30
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• 2001

Purpose : Eyeball movement is one of the main artifacts in EEG. A new approach to the removal of these artifacts is presented using independent component analysis(ICA). This technique is a signal-processing algorithm to separate independent sources from unknown mixed signals. This study was performed to show that ICA is a useful method for the separation of EEG components with little data deformity. Methods : 12 sets of 10 sec digital EEG data including eye opening and closure were obtained using international 10~20 system scalp electrodes. ICA with 18 tracings of double banana bipolar montage was performed. Among obtained 18 independent components, two components, which were thought to be eyeball movements were removed. Other 16 components were reconstructed into original bipolar montage. Power spectral analysis of EEGs before and after ICA was done and compared statistically. Total 12 pairs of data were compared by visual inspection and relative power comparison. Results : Waveforms of each pair looked alike by visual inspection. Means of relative power before and after ICA were 29.16% vs. 28.27%, 12.12% vs. 12.41%, 10.55% vs. 10.52%, and 19.33% vs. 18. 33% for alpha, beta, theta, and delta, respectively. These values were statistically same before and after ICA. Conclusions : We found little data deformity after ICA and it was possible to isolate eyeball movements in EEG recordings. Many other components of EEG could be selectively separated using ICA.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.135-148
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• 2005

In the stage of conceptual design for the construction and operation of the geologic repository for radioactive wastes, it is important to consider a repository ventilation system which serves the repository working environment, hygiene & safety of the public at large, and will allow safe maintenance like moisture content elimination in repository for the duration of the repositories life, construction/operation/closure, also allowing safe waste transportation and emplacement. This paper describes the possible ventilation system design criteria and requirements for the prospective Korean radioactive waste repositories with emphasis on the underground rock cavity disposal method in the both cases of low & medium-level and high-level wastes. It was found that the most important concept is separate ventilation systems for the construction (development) and waste emplacement (storage) activities. In addition, ventilation network system modeling, natural ventilation, ventilation monitoring systems & real time ventilation simulation, and fire simulation & emergency system in the repository are briefly discussed.

• Journal of Energy Engineering
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• v.2 no.3
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• pp.268-275
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• 1993

A series of parametric investigations are performed in order to resolve the flow characteristic of a Quebec city stoker incinerator. The parameters considered in this study are five internal configurations of the Quebec city stoker itself and its modified ones, primary air velocity, the injection velocity and angle of the secondary air, and the reduction of the stoker exit area. A control-volume based finite-difference method by Patankar together with the power-law scheme is employed for discretization. The resolution of the pressure-velocity coupling is made by the use of SIMPLEC algorithm. The standard, two equation, k-$\varepsilon$ model is incorporated for the closure of turbulence. The size of recirculation region, turbulent viscosity, the mass fraction of the secondary air and pressure drop are calculated in order to analyze the characteristics of flow field. The results are physically acceptable and discussed in detail. The flow field of the Quebec city stoker shows the strong recirculation zone together with the high turbulence intensity over the upper part of the incinerator.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.557-568
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• 2016

Squeezing is a phenomenon that may occur in deep tunneling and could bring about a large plastic deformation, tunnel closure and collapse of tunnel supports. Therefore, quantitative estimations of deformation and stress from squeezing and its possibility are necessary for establishment of a rational tunneling method. This study carried out three dimensional numerical analyses using a strain softening model in order to simulate the behaviour of squeezing and to estimate deformation and yield area around tunnels quantitatively. Numerical analyses were performed for 42 cases of various stress and strength conditions. As a result, the maximum tangential stress and strength of rock mass ratio could estimate plastic deformation and yield depth around tunnels and equations of relations between them were proposed.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.17-22
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• 1988

Fractures of the femoral neck in children are rare and usually the result of severe trauma. The femoral necks in children, in contrast to those of adults, have many anatomic and physiologic differences. Among the late complications encountered are avascular necrosis, coxa vara, premature closure of the proximal capital femoral epiphysis and nonunion. In spite of careful management, significant complication rate often results. Nine cases of fractures of the femoral neck in children which were treated at Yeungnam University Hospital from June 1984 to August 1987 were reviewed. The results obtained are as follows: 1. The main causes of fractures were traffic accidents(5 cases). 2. Among 9 patients, 6 were girls and 3 were boys. 3. According to the classification of Delbet and Colonna, the transcervical fracture(6 cases) was the commonest type. 4. 4 cases were treated by closed reduction and internal fixation, 3 cases were treated by open reduction and internal fixation. 2 cases were treated by skin traction and cast. 5. The results were analyzed according to Ratliff's assessment. 6 cases showed good results, and 3 cases showed poor results. 6. Early diagnosis and good fixation method seemed to be vital to prognosis.

• Proceedings of the KSRS Conference
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• v.1
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• pp.21-24
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• 2006

Processes controlling the interannual variation of mixed layer temperature (MLT) averaged over the NINO3 domain ($150-90^{\circ}W$, $5^{\circ}N-5^{\circ}S$) are studied using an ocean data assimilation product that covers the period of 1993 to 2003. Advective tendencies are estimated here as the temperature fluxes through the domain's boundaries, with the boundary temperature referenced to the domain-averaged temperature to remove the dependence on temperature scale. The overall balance is such that surface heat flux opposes the MLT change but horizontal advection and subsurface processes assist the change. The zonal advective tendency is caused primarily by large-scale advection of warm-pool water through the western boundary of the domain. The meridional advective tendency is contributed mostly by Ekman current advecting large-scale temperature anomalies though the southern boundary of the domain. Unlike many previous studies, we explicitly evaluate the subsurface processes that consist of vertical mixing and entrainment. In particular, a rigorous method to estimate entrainment allows an exact budget closure. The vertical mixing across the mixed layer (ML) base has a contribution in phase with the MLT change. The entrainment tendency due to temporal change in ML depth is negligible comparing to other subsurface processes. The entrainment tendency by vertical advection across the ML base is dominated by large-scale changes in wind-driven upwelling and temperature of upwelling water. Tropical instability waves (TIWs) result in smaller-scale vertical advection that warms the domain during La Ni? cooling events. When the advective tendencies are evaluated by spatially averaging the conventional local advective tendencies of temperature, the apparent effects of currents with spatial scales smaller than the domain (such as TIWs) become very important as they redistribute heat within the NINO3 domain. However, such internal redistribution of heat does not represent external processes that control the domain-averaged MLT.