• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.360-373
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• 2017

The BTO-a projects is the types, which has a demand risk among the type of PPP projects in Korea. When demand risk is realized, private investor encounters financial difficulties due to lower revenue than its expectation and the government may also have a problem in stable infrastructure operation. In this regards, the government has applied various risk sharing policies in response to demand risk. However, the amount of government's risk sharing is the government's contingent liabilities as a result of demand uncertainty, and it fails to be quantified by the conventional NPV method of expressing in the text of the concession agreement. The purpose of this study is to estimate the value of investment risk sharing by the government considering the demand risk in the profit sharing system (BTO-a) introduced in 2015 as one of the demand risk sharing policy. The investment risk sharing will take the form of options in finance. Private investors have the right to claim subsidies from the government when their revenue declines, while the government has the obligation to pay subsidies under certain conditions. In this study, we have established a methodology for estimating the value of investment risk sharing by using the Black - Scholes option pricing model and examined the appropriateness of the results through case studies. As a result of the analysis, the value of investment risk sharing is estimated to be 12 billion won, which is about 4% of the investment cost of the private investment. In other words, it can be seen that the government will invest 12 billion won in financial support by sharing the investment risk. The option value when assuming the traffic volume risk as a random variable from the case studies is derived as an average of 12.2 billion won and a standard deviation of 3.67 billion won. As a result of the cumulative distribution, the option value of the 90% probability interval will be determined within the range of 6.9 to 18.8 billion won. The method proposed in this study is expected to help government and private investors understand the better risk analysis and economic value of better for investment risk sharing under the uncertainty of future demand.

• Tuberculosis and Respiratory Diseases
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• v.41 no.1
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• pp.26-35
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• 1994

Background: Bronchioloalveolar cell carcinoma today needs further studies as an early diagnosis will drastically improve the chances of cure. Methods: Twenty-four cases of bronchioloalveolar cell carcinoma for the period of 5 years were studied in terms of incidence, age, sex, underlying diseases, symptoms, radiographic findings, methods of diagnosis, clinical and pathologic staging, methods of treatment, and survival retrospectively. Results: No correlation was found between patients' age, sex and underlying diseases. Most common symptoms were cough(62.5%), chest pain(29.2%), and sputum(29.2%). Of the 24 cases, 13 patients(54.2%) had solitary nodule, 6 patients(25%) had multiple nodules. At the time of diagnosis, 3 patients(12.5%) had the stage I diseases, 3 patients(12.5%) had the stage II diseases, 4 patients(16.7%) had the stage IIIa diseases, 3 patients(12.5%) had the stage IIIb diseases, and 11 patients(45.8%) had the stage IV diseases. 14 cases(58.3%) were found inoperable at the time of admission; they all died within 17 months. In 7 cases with stage I, II, IIIa diseases curative resection were attempted, in 1 case with stage IV disease wedge resection for palliative management was performed, and in 4 cases patients were still alive at the time of conclusion of this study. Conclusion: We conclude that early diagnosis of disease will increase operability and improve chances of survival and that aggressive diagnostic workup for suspicious pulmonary infiltrate is essential as early operation offers the best chances of cure.

• Journal of Environmental Policy
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• v.12 no.3
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• pp.21-47
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• 2013

The aim is to analysis landslide vulnerability in Inje, Korea, using GCI(Geospatial Correlative Integration) and probability rainfalls based on geographic information system (GIS). In order to achieve this goal, identified indicators influencing landslides based on literature review. We include indicators of exposure to climate(rainfall probability), sensitivity(slope, aspect, curvature, geology, topography, soil drainage, soil material, soil thickness and soil texture) and adaptive capacity(timber diameter, timber type, timber density and timber age). All data were collected, processed, and compiled in a spatial database using GIS. Karisan-ri that had experienced 470 landslides by Typhoon Ewinia in 2006 was selected for analysis and verification. The 50% of landslide data were randomly selected to use as training data, while the other 50% being used for verification. The probability of landslides for target years (1 year, 3 years, 10 years, 50 years, and 100 years) was calculated assuming that landslides are triggered by 3-day cumulative rainfalls of 449 mm. Results show that number of slope has comparatively strong influence on landslide damage. And inclination of $25{\sim}30^{\circ}C$, the highest correlation landslide. Improved previous landslide vulnerability methodology by adopting GCI. Also, vulnerability map provides meaningful information for decision makers regarding priority areas for implementing landslide mitigation policies.

• Journal of the Korean Arthroscopy Society
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• v.6 no.1
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• pp.1-6
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• 2002

Purpose : Evaluation and analysis of the incidence and causes of intraoperative and postoperative complications after arthoscopic anterior cruciate ligament(ACL) reconstruction using bone-patella. tendon-bone (BPTB) auto graft. Materials and Methods : We reviewed 85 cases of arthroscopic ACL reconstruction using BPTB autograft which had been followed up for more than 1 year. Intraoperative complications had been recorded and corrected during the operation. Postoperative complications were analyzed and compared between 3 groups which were classified by the last follow-up period after the operation. Results : There were a few intraoperative complications including patellar fracture(1 case), contamination of harvested graft(1 case), impingement of graft(2 cases), blow-out of tile posterior wall of the femoral tunnel(1 case) and intraarticular retraction of the screw(1 case). The result of the comparison of postoperative complications among the groups shows that the incidence of anterior knee pain, donor site pain and patellofemoral crepitation were significantly decreased after 2 years. But there was no significant decrease in these complications after 3 years. Conclusion : Intraoperative complications after arthroscopic ACL reconstruction using BPTB autograft were due to incorrect technique and carelessness of the operation team, and can be prevented by improvement of surgical technique and accumulation of experience. Postoperative complication were somewhat unavoidable but gradually improved with time; hence, we should consider it for the selection of graft donor.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.129-135
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• 1999

Purpose : This study evaluated early bowel complications in cervix cancer patients, following external radiotherapy (ERT and high dose rate intracavitary radiation (HDR ICR). Factors affecting the risk of developing early bowel complications and its incidence are analyzed and discussed Materials and Methods : The study is the retrospective review of 66 patients who received radiotherapy at Chungbuk National University Hospital from April 1994 to December 1998. The patients underwent 41.4 or 50.4 Gy ERT according to FIGO stage and tumor size, then A point dose was boosted to 71.4 or 74.4 Gy using a remotely controlled afterloading Buchler HDR ICR. The EORTC/RTOG morbidity criteria were used to grade early bowel complications, which are valid from day 1, the commencement of therapy, through day 90. The actuarial incidence, severity of complications were investigated and clinical pretreatment factors relevant to complications were found through univariate (Wilcoxon) and multivariate (Cox proportional hazard model) analysis. Results : Of the 66 patients, 30 patients (46$\%$) developed early bowel complications; 25 patients (38$\%$) with grade 1 or 2, 4 patients (0$\%$) with grade 3 and 1 patient (2$\%$) with grade 4. The complications usually began to occur 3 weeks after the commencement of radiotherapy. The actuarial incidence of early bowel complications was 41$\%$ at 10 weeks. The early bowel complications were associated significantly with an old age and a history of previous abdomino-pelvic surgery. All three patients who had a protracted overall treatment time (about 2 weeks) due to severe bowel complication, suffered from pelvic recurrences. Conclusion : Forty six percent of patients experienced early bowel complications, most of which were grade 1 or 2 and relieved spontaneously or by medication. The patients with an old age or a previous surgery have a high probability of early complications and they may be less compliant with planned radiotherapy. So more careful precaution is necessary for these patients.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.28-34
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• 2006

Background: There has been an increase in the number of elderly patients considered for coronary artery bypass grafting (CABG). Recently, there were many satisfactory reports of coronary artery bypass grafting (CABG) in old age due to the development in operative technique and postoperative management. We evaluated operative and follow-up results of patients 70 years of age and older compared to 60 years old. Material and Method: We retrospectively studied the cases of 74 consecutive patients 70 years or older (group A) who underwent a elective CABG from January 2000 to December 2003 and compared that of relatively young age group (group B, 60-69 years old). We compared preoperative characteristics, operation technique, postoperative results that effect outcome, also we investigated late mortality and cardiac events at follow-up periods. Result: Preoperative demographic and clinical characteristics of two groups were not different, except preoperative renal dysfunction(serum creatinine: $\geq$1.4 mg/dl) (group A 17, 23$\%$ vs group B 14, 9$\%$) (p=0.024). There was no difference of the mean number of distal anastomosis and the left ventricular ejection fraction in group A decreased significantly from 53.7$\pm$13$\%$ preoperatively to 49.9$\pm$ 12$\%$ postoperatively (p=0.02), but not changed in group B. There was no difference at operative mortality rate and postoperative major morbidity rate, but wound problem of saphenous vein harvest site was significantly higher in group A than group B (6.8$\%$ vs 0.7$\%$, p=0.02). The mean follow up duration was 24.3$\pm$13 months and the cumulative survival were 95.4$\%$ at 2 year and 79.9$\%$ at 4 year in group A and 95.4$\%$ at 2 year and 90.1$\%$ at 4 year in group B (p=ns). Conclusion: We conclude that age is not a factor of determination when we decide about operation because coronary artery bypass grafting in elderly more than 70 years old can be performed with a low mortality rate and acceptable morbidity rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.510-517
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• 2015

Miscanthus has been considered as the most promising bioenergy crop for lignocellulosic biomass production. In Korea, M. sacchariflorus and M. sinensis can be found easily in all regions. It is a great advantage to utilize as important species with respect to genetic and cross-breeding programs materials for creation of novel hybrids. For successful breeding programs, it is important to precisely understand the variability of flowering traits among Miscanthus species as breeding parents materials. In this study, flowering traits were observed daily in 960 germplasms of two Miscanthus species (M. sacchariflorus and M. sinensis) for growing seasons over 2 years. The flowering process was divided into three stages. ST (sprouting time) was recorded when first leaf of the plant emerged on soil. FS1 (flowering stage 1) and FS2 (flowering stage 2) were recorded when flag leaf was firstly observed, and 1 cm of panicle was showing on at least one stem, respectively. For 2013 and 2014, the latest germplasms exerted flag leaf, i.e. September 30 (DOY of FS1 164.1) and September 4 (DOY of FS1 141.0) occurred M. sacchariflorus cv. Geodae 1 and M. sacchariflorus cv. Uram collected from Southern Korea (Jeollanam-do), while Miscanthus germplasms collected from northern Korea (Gyeonggi-do) which emerged the earliest flag leaf in July and August, significantly decreased DOY. For DOY from ST to FS2, M. sacchriflorus germplasms ranged from 140 to 190 days, and 110 to 170 days for 2013 and 2014. The highest frequency showed to 160 days for 2013, and 150 days for 2014. In M. sinensis germplasms, the highest frequency showed to 180 days for 2013, and 170 days for 2014. In the results of correlation between the day of years from ST to FS2 for 2013 and 2014, M. sacchriflorus and M. sinensis showed high coefficient of correlation (0.70 and 0.89). It can be supposed that flowering characteristics of Miscanthus are largely affected by the unique phenotypic characteristic of native habitat than environmental factors of the current planted site. This study for flowering traits of Miscanthus may provides an important information in order to expedite the introduction as breeding materials for creation of new hybrid.

• The Journal of the Petrological Society of Korea
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• v.19 no.1
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• pp.31-49
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• 2010

Nearly NS-trending Fe-Ti ore bodies intermittently occur in the Hadong anorthosites, south Korea, irrespective of the rock types of the anorthosites. In order to determine their occurrence mode and deformation history, we collected the features of occurrence and geological structures in the field, petrographic features using thin sections of the principal constituent rocks, and geochemical data of ilmenites in the ore body using electron probe microanalysis. Fe-Ti ore bodies examined in this study are divided into two types: dike- and lamina-types. It is steadily supported that the dike-type has intruded into the anorthositic rocks after their emplacement and solidification. And the laminar-type is probably a result of the mylonitization and transposition of the dike-type ore bodies parallel to the shear planes, due to later strong dextral ductile shearing. In the meantime, the Fe-Ti ore bodies have experienced the stronger dextral shearing in the more northern part of the study area, i.e. Cheongryong-ri, Wolhoeng-ri, Jonghwa-ri, and Jayangri and Baekun-ri in ascending order of its strength, together with the less content of $TiO_2$. All ilmenites of the ore bodies have very similar chemical composition, as pure ilmenite of 52~55 wt.% in $TiO_2$ content, irrespective of the occurrence mode and degree of later ductile shearing of the ore bodies. And they didn't experience to exsolve into magnetite. The structural data indicate that the Hadong anorthosites have deformed by NNE-trending folding, intrusion of the Fe-Ti ore bodies, NNW~NNE-trending dextral ductile shearing, NW~NNW-trending sinistral semi-brittle shearing, and intrusion of NNE~NE-trending mafic dykes in descending order of chronology after the formation of foliation of the anorthositic rocks. The foliation is interpreted as a result of the accumulation of crystals that settle out from the magma by the action of gravity.

• The Journal of the Petrological Society of Korea
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• v.26 no.1
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• pp.45-54
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• 2017

The characteristics of the rock cleavage in Jurassic Geochang granite were analysed using the distribution of microcrack lengths and spacings. The phases of distribution of the above lengths and spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. First, the length and spacing-cumulative diagrams for the six directions of rock cleavages were arranged in increasing order($H2{\rightarrow}R1$) on the density(${\rho}$) of microcrack length. The various parameters were extracted through the combination of the above two types of diagrams. The discrimination factors representing the three quarrying planes and three rock cleavages were acquired through the mutual contrast between the values of parameters. The analysis results of the research are summarized as follows. The evaluation for the six directions of rock cleavages was performed using the parameters such as (1) intersection angle(${\alpha}-{\beta}$) and (2) exponent difference(${\lambda}_S-{\lambda}_L$) between two exponential straight lines related to spacing(${\alpha}$, ${\lambda}_S$) and length(${\beta}$, ${\lambda}_L$). The values of parameters(1 and 2) are in order of H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2). On the contrary, the values of the above two parameters for three planes are in order of R < G < H. Meanwhile, the direction of convergence between two exponential straight lines was derived. The above direction is compliant to arrangement of the line os' centering around the line ol. The above two lines converge in the direction of the Y-axis when the line ol and line os' occupy the upper region on the left and the lower region on the right, respectively(R-type). On the contrary, the above two lines converge in the direction of the X-axis when the order of arrangement between line ol and line os' is reversed(H-type). Especially, the positive(+) or negative(-) value of intersection angle(${\alpha}-{\beta}$) is determined by the arrangement of two vertical lines. This type of correlation analysis is useful for evaluating the relative strength of rock cleavage and discriminating three quarrying planes.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.136-147
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• 2009

Statement of problem: Since the introduction of the concept of osseointegration in dental implants, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. Purpose: The aim of this retrospective study was to provide long-term data on the $Implantium^{(R)}$ implant, which features a sandblasted and acid-etched surface and internal connection with microthreads. Material and methods: 106 $Implantium^{(R)}$ implants placed in 38 patients at Yonsei University Hospital were examined to determine the effect of various factors on implant success and marginal bone loss, through clinical and radiographic results during a 6 to 30 month period. Results: 1. Out of a total of 106 implants placed in 38 patients, one fixture was lost, resulting in a 99.1% cumulative survival rate. 2. Among the 96 implants which were observed throughout the study period, the survival rates were 97.0% in the maxilla and 100% in the mandible. The survival rate in the posterior regions was 98.9% and 100% in the anterior regions. 3. The mean bone loss during the first year after prosthesis placement was 0.17 mm, while the mean annual bone loss after the first year was 0.04 mm, which was statistically less than during the first year(P<.05). 4. There was no significant difference in marginal bone loss according to age during the first year(P>.05), but after the first year, the mean annual bone loss in patients above 50 years was significantly greater(P<.05) compared with patients under 50 years. 5. No significant difference in marginal bone loss was found according to the following factors: gender, jaw, location in the arch, type of implant(submerged or non-submerged), presence of bone grafts, type of prostheses, and type of opposing dentition(P<.05). Conclusion: Based on these results, the sole factor influencing marginal bone loss was age, while factors such as gender, jaw, location in the arch, type of implant, presence of bone grafts, type of prostheses and type of opposing dentition had no significant effect on bone loss. In the present study, the success rate of the $Implantium^{(R)}$ implant with a SLA surface and internal connection with microthreads was satisfactory up to a maximum 30 month period, and the marginal bone loss was in accord with the success criteria of dental implants.