• The Korean Journal of Air & Space Law and Policy
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• v.12
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• pp.246-274
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• 2000

This paper discusses the qualification criteria for international hub airport and suggests the strategies for Inchon International Airport (IIA) to be the hub airport in the East Asia. Recently, many East and Southeast Asia countries have invested on large scale international airports like Chap Lak Kok airport, Pudong airport etc.. as Korea have done on IIA. IIA to be open in 2001 will face a serious competition with these airport. Being a hub airport requires geographic proximity. sufficient volume of local traffic. uncongested infrastructure, a good accessibility to surrounding industrial centers. high quality of service to the airline. In order to promote airlines to land at IIA. Korea Government need to establish Open Sky Policy to many countries and national flag carriers of Korea need to be involved in a global alliance. Developing vicinity of IIA as free trade zone will generated more local traffic which makes IIA as more attractive candidate for airlines. The Korea airspace is one of the most restricted area in the world becuase of the national security. which limits civil aircraft maneuvers. The airspace need to be re-structured to exploit the full capacity of IIA.

• Archives of Reconstructive Microsurgery
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• v.21 no.2
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• pp.118-130
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• 2012

Background: Women receiving mastectomy usually prefer a single-stage surgical procedure without the need for additional surgery. Hence, nipple sparing mastectomy was introduced, and the follow-up data on the aesthetic outcome and recurrence of breast cancer were investigated in this study. Materials and Methods: The study subjects comprised 22 patients who received nipple-sparing mastectomy and immediate breast reconstruction using the free transverse abdominal rectus abdominis myocutaneous flap between June of 2007 and June of 2012. The patients' aesthetic outcomes were measured with 2 methods for the objective result: Breast size measurements and breast volume calculation both at preoperative phase and postoperative 1 years phase. Also, the patients' satisfaction was evaluated at postoperative 1 year with the self-assessment questionnaire. Follow up check for assessing cancer recurrence was performed for an average period of postoperative 1063 days. Results: First, in objective aesthetic outcome, there were no significant differences between the preoperative and postoperative results on both the breast size and the volume. Second, the patient satisfaction analysis scores were graded as very good in 15 patients (68.2%), and as good in 6 patient (27.3%). Most of the patients were very satisfied with our surgery method. Last, there was no local or distant recurrence in these 22 patients during the follow-up period. Conclusion: In this study, the nipple-sparing mastectomy achieved satisfactory results for the breast scar and shape with a single-stage surgical procedure, and the cancer recurrence rate was not significantly different from that of the conventional mastectomy. Besides, the nipple-sparing mastectomy is more cost-effective than the conventional mastectomy since it reduces the need for additional procedures. However, we think that it is necessary to determine the long-term outcomes about the recurrence rate.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.232-240
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• 2014

Transonic flow past a NASA SC(2)-0710 airfoil with deployments of a spoiler up to $6^{\circ}$ was studied numerically. We consider angles of attack from $-0.6^{\circ}$ to $0.6^{\circ}$ and free-stream Mach numbers from 0.81 to 0.86. Solutions of the unsteady Reynolds-averaged Navier-Stokes equations were obtained with a finite-volume solver using several turbulence models. Both stationary and time-dependent deployments of the spoiler were examined. The study revealed the existence of narrow bands of the Mach number, angle of attack, and spoiler deflection angle, in which the flow was extremely sensitive to small perturbations. Simulations of 3D flow past a swept wing confirmed the flow sensitivity to small perturbations of boundary conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.600-605
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• 2011

This paper shows field test and evaluation results for a wireless vehicle detector with anisotropic magneto-resistive (AMR) sensors. The detector consists of two AMR sensors and mechanical and electronic apparatuses. The AMR sensor senses disturbance of the earth magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. In this paper, vehicle speeds are calculated by using two AMR sensors fixed on a board, with constant distance. To test and evaluate the accuracy of the detector in real traffic situations, the detector was installed on a local highway and vehicle speeds and volumes were measured both in a free running and a highly congested traffic. The measurements from the detector are compared with the reference measurements obtained from a traffic camera with the Mean Absolute Percentage Errors (MAPE), which has proved the usefulness of the detector in the field.

• Archives of Reconstructive Microsurgery
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• v.22 no.1
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• pp.24-28
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• 2013

Purpose: Soft tissue defect of the hand, which cannot be covered with skin graft or local flap, is usually reconstructed using a free flap. Temporoparietal fascial free flap is one of the best alternatives for functional reconstruction of the hand with exposed tendons, bones, and joints. Materials and Methods: We have experienced four cases of reconstruction using a temporoparietal fascial flap with a skin graft and followed up for 20 years. We conducted a retrospective review of the patients' clinical charts and photos. Results: At the time of initial injury, the average age of patients was 50.3 (39~62) years. The radial artery was used for reconstruction of the dorsal side of the hand, whereas the ulnar artery was used for that of the volar side of the wrist. Short term complication such as skin graft loss and donor site alopecia occurred. However, during the long term follow-up period, no change of flap volume was noted, and full range of motion in the adjacent joint was maintained. In addition, hyperpigmentation of the grafted skin on the flap disappeared gradually. Conclusion: Selection of the optimal flap is important for reconstruction of the hand without functional limitation. We obtained satisfactory soft tissue coverage and functional outcomes using a temporoparietal fascial free flap and followed up for 20 years.

• Journal of Korean Neurosurgical Society
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• v.45 no.5
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• pp.275-283
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• 2009

Objective : We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction. Methods : In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was $12.4cm^3$. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria. Results : Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age(<60 years) and tumor volume affected survival rate(p=0.03, each). Acute (${\leq}$1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21 %, respectively. Less acute toxicity was observed with small tumors (<$10cm^3$. p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gy${\times}cm^3$) was a significant predictor of both acute and chronic CNS toxicities. Conclusion: Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4861-4864
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• 2014

Background: The Ewing's sarcoma family is a group of small round cell tumors which accounts for 10-15% of all primary bone neoplasms. The aim of this study was to evaluate the survival of Ewing's sarcoma patients in our province and to determine of influencing factors. Materials and Methods: All patients with documented Ewing's sarcoma/primitive neuroectodermal tumor(PNET) family pathology were enrolled in this study during a period of eight years. For all of them local and systemic therapy were carried out. Overall and event free survival and prognostic factors were evaluated. Results: Thirty two patients were enrolled in the study. The median age was 17.5 years. Twenty (65.2%) were male and 9 (28.1%) were aged 14 years or less. Mean disease free survival was 26.8 (95%CI; 13.8-39.9) months and five year disease free survival was 26%. Mean overall survival was 38.7 months (95%CI; 25.9-50.6) and median overall survival was 24 months. Five year overall survival was 25%. From the variables evaluated, only presence of metastatic disease at presentation (p value=0. 028) and complete response (p value =0. 006) had significant relations to overall survival. Conclusions: Survival of Ewing's sarcoma in our province is disappointing. It seems to be mostly due to less effective treatment. Administration of adequate chemotherapy dosage, resection of tumor with negative margins and precise assessment of irradiation volume may prove helpful.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.5
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• pp.445-452
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• 2015

A tubular packed bed reactor for the steam-$CO_2$ combined reforming of natural gas to produce the synthesis gas of a target $H_2/CO$ ratio 2.0 was simulated. The effects of the reactor dimension, the feed gas composition, and the gas feeding temperature upon the possibility of coke formation across the catalyst bed were investigated. For this purpose, 2-dimensional heterogeneous reactor model was used to determine the local gas concentrations and temperatures over the catalyst bed. The thermodynamic potential distribution of coke formation was determined by comparing the extent of reaction with the equilibrium constant given by the reaction, $CH_4+2CO{\Leftrightarrow}3C+2H_2O$. The simulation showed that catalysts packed in the central region nearer the entrance of the reactor were more prone to coking because of the regional characteristics of lower temperature, lower concentration of $H_2O$, and higher concentration of CO. With the higher feeding temperature, the feed gas composition of the increased $H_2O$ and correspondingly decreased $CO_2$, or the decrease in the reactor diameter, the volume fraction of the catalyst bed subsequent to coking could be diminished. Throughout the simulation, reactor dimension and reaction condition for coking-free operation were suggested.

• Radiation Oncology Journal
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• v.32 no.3
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• pp.163-169
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• 2014

Purpose: To report the results of stereotactic body radiotherapy (SBRT) for unresectable primary or recurrent cholangiocarcinoma. Materials and Methods: From January 2005 through August 2013, 58 patients with unresectable primary (n = 28) or recurrent (n = 30) cholangiocarcinoma treated by SBRT were retrospectively analyzed. The median prescribed dose was 45 Gy in 3 fractions (range, 15 to 60 Gy in 1-5 fractions). Patients were treated by SBRT only (n = 53) or EBRT + SBRT boost (n = 5). The median tumor volume was 40 mL (range, 5 to 1,287 mL). Results: The median follow-up duration was 10 months (range, 1 to 97 months). The 1-year, 2-year overall survival rates, and median survival were 45%, 20%, and 10 months, respectively. The median survival for primary group and recurrent group were 5 and 13 months, respectively. Local control rate at 1-year and 2-year were 85% and 72%, respectively. Disease progression-free survival rates at 1-year and 2-year were 26% and 23%, respectively. In univariate analysis, ECOG performance score (0-1 vs. 2-3), treatment volume (<50 vs. ${\geq}50mL$), and pre-SBRT CEA level (<5 vs. ${\geq}5ng/mL$) were significant in overall survival rate. In multivariate analysis, ECOG score (p = 0.037) and tumor volume (p = 0.030) were statistically significant. In the recurrent tumor group, patients with >12 months interval from surgery to recurrence showed statistically significant higher overall survival rate than those with ${\leq}12$ months (p = 0.026). Six patients (10%) experienced ${\geq}$grade 3 complications. Conclusion: SBRT can be considered as an effective local modality for unresectable primary or recurrent cholangiocarcinoma.

• Korean Journal of Radiology
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• v.22 no.9
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• pp.1525-1536
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• 2021

Objective: To investigate the feasibility of cine three-dimensional (3D) balanced steady-state free precession (b-SSFP) imaging combined with a non-local means (NLM) algorithm for image denoising in evaluating cardiac function in children with repaired tetralogy of Fallot (rTOF). Materials and Methods: Thirty-five patients with rTOF (mean age, 12 years; range, 7-18 years) were enrolled to undergo cardiac cine image acquisition, including two-dimensional (2D) b-SSFP, 3D b-SSFP, and 3D b-SSFP combined with NLM. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) of the two ventricles were measured and indexed by body surface index. Acquisition time and image quality were recorded and compared among the three imaging sequences. Results: 3D b-SSFP with denoising vs. 2D b-SSFP had high correlation coefficients for EDV, ESV, SV, and EF of the left (0.959-0.991; p < 0.001) as well as right (0.755-0.965; p < 0.001) ventricular metrics. The image acquisition time ± standard deviation (SD) was 25.1 ± 2.4 seconds for 3D b-SSFP compared with 277.6 ± 0.7 seconds for 2D b-SSFP, indicating a significantly shorter time with the 3D than the 2D sequence (p < 0.001). Image quality score was better with 3D b-SSFP combined with denoising than with 3D b-SSFP (mean ± SD, 3.8 ± 0.6 vs. 3.5 ± 0.6; p = 0.005). Signal-to-noise ratios for blood and myocardium as well as contrast between blood and myocardium were higher for 3D b-SSFP combined with denoising than for 3D b-SSFP (p < 0.05 for all but septal myocardium). Conclusion: The 3D b-SSFP sequence can significantly reduce acquisition time compared to the 2D b-SSFP sequence for cine imaging in the evaluation of ventricular function in children with rTOF, and its quality can be further improved by combining it with an NLM denoising method.