The bilateral sagittal split ramus osteotomy (BSSRO) is preferred method of surgical correction for mandibular prognathism, retrognathism and asymmetry. This technique performed from primarily an intraoral incision to avoid a scar. After forward movement of the distal segment of the mandible, healing of bone by primary or secondary intention is easily accomplished through large areas of cancellous bony overlap. When rigid fixation is used for the BSSRO, it is possible to open the mouth during the immediate post-operative period because it promotes the healing process. Although this surgical procedure has been well-documented, the incidence of postoperative trigeminal neurosensory disorder in the region of the inferior alveolar nerve and the mental nerve remains one of the major complication. However, evaluation of objective methods for sensory recovery patterns is insufficient although most patients find their sensory return. Neurometer electrodiagnostic device performs automated neuroselective sensory nerve conduction threshold evaluation by determining current perception threshold (CPT) measures. The purpose of this study was to evaluate the sensory recovery patterns of inferior alveolar and mental nerve over time. Nerve examination with a neurometer was performed in 30 patients undergoing the BSSRO at pre-operative, post-operative 1-, 2-, 4- week, and 2-, 3-, 4-, 5-, 6- month follow-up visits after the osteotomy to compare the differences of nerve injury and recovery patterns after the BSSRO with or without genioplasty and sensory recovery patterns associated with the kind of nerve fiber.
Journal of the Computational Structural Engineering Institute of Korea
/
v.29
no.2
/
pp.141-148
/
2016
The long-span bridges such as Incheon Bridge and Seohae Grand Bridge are located on the coastal region effected frequently by strong wind of typhoons. In order to ensure the wind-resistant performance of the structure, estimation of the proper design wind speed is very important. In this study, stochastic estimation of design wind speed incurred by typhoons is carried out. For this purpose, we first established probability distribution of climatological parameters such as central pressure depth, distance of closest approach, translation speed and heading to build statistical model of typhoons, which are employed in Monte Carlo simulation for hypothetical typhoons. Once a typhoon is generated with statistically justified parameters, wind speeds are estimated along its path using wind field model. Thousands of typhoons are generated and their peak wind speeds are utilized to establish the extreme wind speeds for different return period. The results are compared with design basic wind speeds in Korean Highway Bridge Design Code, showing that the present results agree well with similar studies while the existing code suggests higher design wind speed.
Purpose - This paper's aim is to investigate whether or not gross profitability explains the cross-sectional variation of the stock returns in the Korean stock market. Gross profitability is an alternative profitability measure proposed by Novy-Marx in 2013 to predict cross-sectional variation of stock returns in the US. He shows that the gross profitability adds explanatory power to the Fama-French 3 factor model. Interestingly, gross profitability is negatively correlated with the book-to-market ratio. By confirming the gross profitability premium in the Korean stock market, we may provide some implications regarding the well-known value premium. In addition, our empirical results may provide opportunities for the fund distribution industry to promote brand new styles of funds. Research design, data, and methodology - For our empirical analysis, we collect monthly market prices of all the companies listed on the Korea Composite Stock Price Index (KOSPI) of the Korea Exchanges (KRX). Our sample period covers July1994 to December2014. The data from the company financial statementsare provided by the financial information company WISEfn. First, using Fama-Macbeth cross-sectional regression, we investigate the relation between gross profitability and stock return performance. For robustness in analyzing the performance of the gross profitability strategy, we consider value weighted portfolio returns as well as equally weighted portfolio returns. Next, using Fama-French 3 factor models, we examine whether or not the gross profitability strategy generates excess returns when firmsize and the book-to-market ratio are controlled. Finally, we analyze the effect of firm size and the book-to-market ratio on the gross profitability strategy. Results - First, through the Fama-MacBeth cross-sectional regression, we show that gross profitability has almost the same explanatory power as the book-to-market ratio in explaining the cross-sectional variation of the Korean stock market. Second, we find evidence that gross profitability is a statistically significant variable for explaining cross-sectional stock returns when the size and the value effect are controlled. Third, we show that gross profitability, which is positively correlated with stock returns and firm size, is negatively correlated with the book-to-market ratio. From the perspective of portfolio management, our results imply that since the gross profitability strategy is a distinctive growth strategy, value strategies can be improved by hedging with the gross profitability strategy. Conclusions - Our empirical results confirm the existence of a gross profitability premium in the Korean stock market. From the perspective of the fund distribution industry, the gross profitability portfolio is worthy of attention. Since the value strategy portfolio returns are negatively correlated with the gross profitability strategy portfolio returns, by mixing both portfolios, investors could be better off without additional risk. However, the profitable firms are dissimilar from the value firms (high book-to-market ratio firms); therefore, an alternative factor model including gross profitability may help us understand the economic implications of the well-known anomalies such as value premium, momentum, and low volatility. We reserve these topics for future research.
Korean Journal of Construction Engineering and Management
/
v.18
no.2
/
pp.81-90
/
2017
In Imjin River basin, three floods occurred between 1996 and 1999, causing many casualties and economic losses of 900 billion won. In Korea, flood damage is expected to increase in the future due to climate change. This study used the climate scenarios to estimate future flood damage costs and suggested a real options-based economic assessment method. Using proposed method, the flood control infrastructures in Imjin River basin were selected as a case study site to analyze the economic feasibility of the investment. Using RCP (Representative Concentration Pathway) climate scenarios, the future flood damage costs were estimated through simulated rainfall data. This study analyzed the flood reduction benefits through investment in the flood control infrastructures. The volatility of flood damage reduction benefits were estimated assuming that the RCP8.5 and RCP4.5 climate scenarios would be realized in the future. In 2071, the project option value would be determined by applying an extension option to invest in an upgrading that would allow the project to adapt to the flood of the 200-year return period. The results of the option values show that the two investment scenarios are economically feasible and the project under RCP8.5 climate scenario has more flood damage reduction benefits than RCP4.5. This study will help government decision makers to consider the uncertainty of climate change in the economic assessment of flood control infrastructures using real options analysis. We also proposed a method to quantify climate risk factors into economic values by using rainfall data provided by climate scenarios.
The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.
This study was conducted to examine the seasonal pattern of N and P uptake by reeds (Phragmites australis) planted in newly constructed Shihwa tidal freshwater marshes. Reed and soil samples were collected from the wetland periodically from June 2000 to May 2002. Reed samples were analyzed for dry weight and content of N and P Soil organic matter content and salinity were also determined. Dry matter content of reed increased during the growing season but decreased in the fall and winter. However, this seasonal pattern was not so evident in the second year. In particular, throughout the measurement period, dry matter content of reed was lowest at a site showing high soil salinity. Regression analyses between dry matter content of reed and soil EC(1:5) suggested that dry matter content per unit square meter would decrease by 1.5 kg with every 1 dS m/sup -1/ increase in soil EC(1:5). The amount of N and P assimilated by reed significantly decreased from the fall and was lowest in the spring. Net decrease in N content from reed during the fall and next spring was calculated as 34.5 and 24.6 g m/sup -2/ in the first and second years, respectively, while the corresponding P loss was 4.0 and 1.8 g m/sup -2/. Soil organic mailer content increased in the fall and winter, but decreased in the spring and summer. The results of this study suggested that the removal of N and P by reed would be considerable during the growing season but the nutrients taken up by reeds would return as detritus to the marshes in the fall and winter. Based on the results of the study, therefore, the harvest of the reed at the latter part of the growth would be recommended to prevent further water quality degradation. However, the long-term effects of reed harvest needs further study.
A new demand for vegetable peanut (Arachis hypogaea L.) in Korea has increased farmers interest in growing vegetable peanut. Compared to grain peanut production, vegetable peanut production enables the growth period to be shortened by 20 or 30 days and farmers to adopt various cropping systems and to return crop residues in the soil. With the purpose of establishing desirable cropping systems for sustainable vegetable peanut production, three field experiments were conducted from 2000 to 2001 at Milyang, the southeastern part of Korea. Main focuses were given into the effect of cropping systems for vegetable peanut production on each crop's yield and soil sustainability. The cropping systems investigated were single vegetable peanut, peanut-radish-green barley, peanut-barley, and peanut-garlic cropping system, with or without crop residue incorporation in the soil. Among the cropping systems investigated for sustainable vegetable peanut production, peanut-only and peanut-radish-green barley cropping systems showed vulnerable to diseases and lodging while peanut-barley and peanut-garlic cropping systems showed higher stability in response to diseases and lodging, consequently leading to higher yield potential of vegetable peanut production. In the peanut-barley cropping system, both barley and peanut residues returned to the soil played an important role in soil improvement as well as in significantly increased grain yield of peanut and barley. A particular notice was taken to the pronounced increase in Trichoderma population and the amount of nitrogen mineralization induced by the returned barley residue. Soil structure, compactness, pH, and fertility were positively influenced by the returned crop residues, which apparently increased sustainability in vegetable peanut production systems.
Using geomorphoclimatic unit hydrograph(GCUH), we estimated the fitness to calculate the mountainous area discharge and flash flood trigger rainfall(FFTR). First, we compared the GCUH peak discharge with the existing report using the design storm at the Dukcheon basin. Second, we compared the HEC-HMS(Hydrologic Engineering Center-Hydrologic Modeling System) model and GCUH with the observed discharge using the real rainfall events at the Taesu stage gage. Third, GCUH and NRCS(Natural Resources Conservation Service) were used for calculating FFTR and proper calculation method was shown. At the Dukcheon basin, the comparison result of using design storm was shown in Table 11, and it was not in excess of 1.1, except for the 30 year return period. In case of real rainfall events, the result was shown in Table 12, and GCUH discharges were all larger than the HEC-HMS model discharges, and they were very similar to the observed data at the Taesu stage gage. In this study, we found that GCUH was a very proper method in the calculation of mountainous discharge. At the Dukcheon basin, FFTR was 12.96 mm in the first 10 minutes when the threshold discharge was 95.59 $m^3$/sec.
Park, Bong-Wook;Byun, June-Ho;Shin, Hee-Suk;Kim, Jong-Ryoul
Maxillofacial Plastic and Reconstructive Surgery
/
v.30
no.1
/
pp.83-91
/
2008
The goal of reconstruction following ablative therapy for intraoral cancer is the restoration of form and function to permit a return to activities of daily life. Traditional reconstruction includes split thickness skin grafts, myocutaneous flaps and, more recently, various free flaps. Free flaps provide higher level of functional recovery relative to that seen with other techniques but require the complexity of the technique and microvascular anastomosis and thus, extended surgical time and occasionally a second team for harvesting. The platysma myocutaneous cervical flap is a possible alternative for intraoral reconstruction. It is thin and pliable like the tissue provided by the radial forearm free flap. It can be harvested with enough tissue to close most head and neck ablative defects. There is virtually no donor site morbidity involved. This study evaluated 7 patients affected by intraoral squamous cell carcinoma (SCC). All patients underwent the resection of intraoral SCC with neck dissection and subsequent intraoral reconstruction with the superiorly based platysma myocutaneous cervical flap. Flap-related complications occurred in 3 patients. Adjuvant radiation therapy was performed in 3 patients. Average follow-up was 24.1 months after surgery, with a range of 8 to 42 months. All patients presented self assessment of discomfort associated with intraoral recipient sites and cervical donor sites. However, the neck function measured by two-inclinometer technique was within the normal range during relatively long term follow-up period. Our study concluded that superiorly based platysma myocutaneous cervical flap is good alternative to free flaps, especially for relatively smaller defects and for the defects appropriate for the rotation arc of the flap.
Korea is classified into low and moderate seismic zone from the view-point of seismic hazard level. Korean seismic provisions has been developed based on UBC and ATC 3-06. Thus, in calculation of design base shear according to Korean provisions response modification factor (R) is included in the formula of design base shear. The major role of this factor is to reduce the elastic design base shear whereby structures can behave in inelastic range during design level earthquake ground motions(mean return period of 475 yrs.). R factor is assigned according to material and structural systems. In this study, R factor for bearing wall system is considered. Most of the walls of apartment buildings in Korea resist gravity and seismic loads simultaneously so that this wall system can be classified into bearing wall system. Structural details of these walls are different from those used in Japan and U.S.. They are all rectangular in sectional shape rather than barbell in shape, and also have special lateral reinforcement details at the boundaries of a wall. In Korean seismic design provisions(1988), two different values(3.0 and 3.5) of R factor are assigned to the bearing wall systems according to the wall details. However, in updated seismic provisions(2000), only one value is assigned to R factor(3.0) irrespective of wall details. In this study, the design base shear values in Korean seismic design provisions(1988, 2000), ATC 3-06, UBC are compared. Also experimental study was carried out to evaluate the seismic performance of structural walls. For this purpose, five test specimens were made which have special details used in apartment bearing wall systems in Korea. Based on the results of this study, response modification factor for bearing wall system is discussed.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.