• Journal of Construction Engineering and Project Management
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• v.1 no.3
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• pp.28-37
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• 2011

Domestic construction companies are suffering from financing difficulties in the wake of the economic slump in Korea and abroad. During this economic slump, real estate investment trusts (REITs), facilitators for improving financing and stimulating construction businesses, have increasingly expanded since their introduction in 2001. However, in terms of growth speed and marketing size, Korean REITs are falling behind those of other nations. The purpose of this study is to suggest a method for composing a portfolio using the Markowitz portfolio selection model to stimulate REITs. The main contents are as follows. First, a comparative analysis was conducted of increased REIT profit with the application of the Markowitz model and the average REIT profit rate from July 3, 2007, to July 21, 2008, during the investment analysis periods. The results showed that the total profit rate from the Markowitz model was about 10% higher than the average REIT profit rate. Second, the sensitivity was analyzed according to the portfolio's data-gathering and replacement cycle to measure the optimum cycle and yield. The six-mouth profit data collection period showed about 16% higher profits with the Markowitz model than with the REITs. The two-week portfolio change period resulted in about 11% higher profits with the Markowitz model than with the REITs.

• Korean Journal of Organic Agriculture
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• v.31 no.4
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• pp.259-289
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• 2023

This study analyzed farmers' and experts' perceptions of the Agricultural Income Survey (AIS) conducted by the Rural Development Administration and estimated its socioeconomic value. The research surveyed 104 farmers in Gyeongsangbuk-do and Jeollanam-do. To estimate the AIS's socioeconomic value, this study examined public information projects in the field of agriculture and public information, proposing an estimation methodology based on prior research. The socioeconomic value of the AIS was calculated in three stages (information generation, collection and analysis, and utilization) using the replacement cost and contingent valuation methods. In 2020, the estimated socioeconomic value of the AIS ranged from a minimum of KRW 631.2 billion to a maximum of KRW 799.1 billion per year. To improve the socioeconomic value of the AIS, it is important to booster awareness, expand sample sizes for more reliable data, increase manpower and budget, refine survey questions, and enhance analyzing capabilities. And it's crucial to foster cooperation with surveyed farms, promote collaboration among investigative agencies, improve investigator skills, and strengthen management capabilities to facilitate information dissemination.

• Journal of Chest Surgery
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• v.38 no.3 s.248
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• pp.204-213
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• 2005

In spite of the improvement in the quality of artificial heart valves and surgical techniques, the incidence of the complications following valve replacement is still high. We reviewed the clinical results of the valve replacements peformed in Korean University Anam Hospital during the last 26 years. Material and Method: The data of 571 patients who received valve replacement between December 1976 and December 2003 were reviewed. Result: There were 304 cases of MVR which was the most common procedure performed. There were 122 cases of AVR, and 111 cases of AVR with MVR. Among the 47 patients who received redo operation 38 cases were redo cases including 31 cases of MVR. $32.5\%$ of the patients who had tissue valve replacement had second valve replacement with 10.2 $\pm$ 3.9 years interval. $24.3\%$ (139/571) of the patients developed valve related complications and cerebral infarction was the highest in frequency. Atrial fibrillation was related with increased complication rates and the mechanical valve replaced group had higher hemorrhagic complication rate than tissue valve replaced group. The operative mortality was $3.68\%$ and the most common cause of the failure was low output syndrome. The operative mortality was higher in the patient group who had valve replacement before the year 1990. The patient group who had mechanical valve replacement had higher operative mortality rate th;3n the tissue valve group. The 5-year survival rate was $92.2\%$ and 10 year survival rate was $85.7\%$. Conclusion: The operative mortality of valve replacement has been improved. The mechnical valve replaced patients had higher hemorrhagic complication rate than the tissue valve replaced patients and more tissue valve replaced patients received redo valve replacement.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.259-262
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• 2003

Fabric hand is ultimately a subjective response to physical stimuli, but there are clearly practical advantage in the development and commercial trading of textile fabrics to be gained from the replacement of the traditional subjective tactile assessment by an objective measurement evaluation method. Moreover, the reliable objective measurement method for warp knitted fabrics have not developed yet, despite their increasing importance. (omitted)

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.569-576
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• 2000

This study performs a series of Triaxial Compression Test for clay-sand composite specimens changing area replacement ratio. Purpose of the test is to conform the propriety of weighted average method in estimating shear strength of the composite ground. The test results show that measured values of shear strength of composite specimens are larger by 20∼30% than those from estimation using the current weighted average method. It is thought that the differences are from pseudo-overconsolidation behavior of composite specimens.

• Journal of Biomedical Engineering Research
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• v.5 no.2
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• pp.121-126
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• 1984

A new approach to texture classification for quantitative ultrasound liver diagnosis using run difference matrix was developed. The run difference matrix comprised the gray level difference along with a distances. From this run difference matrix, we defined several vectors and parameters such as DOD, DGD, DAD vector, SHP, SMO, SMG, LDE, LDEL etc.Each parameter values calculated in fatty, cirrhotic, normal and chronic hepatitic liver images were plotted in a plane and we found that RDM method was more sensitive to small structural changes than the conventional run length method and showed improved classification ability between the diseases.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.682-687
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• 2005

High quality power supplying of power distribution system in electric railway system is the important function. Power feeding system is complicated witch is compose with distribution line, circuit break, protection facilities and so on. Among this components, role of substation is most important for elevation of reliability in electric power system. Therefore, the enhanced reliability considering the preventive inspection, repair work, replacement is necessary. In this study, a proposed the enhanced reliability method through a calculation of fault probability in power feeding system.

• Journal of the Ergonomics Society of Korea
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• v.7 no.2
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• pp.15-21
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• 1988

Changes of the surface area and the volume of limb are important factors for designing clothes and shoes. The limb volume increases slightly in the afternoon in general, because of human activity, as a diurnal variation. Changes are also associated with menstrual cycle, pregnancy, physical exercise and environmental temperature. The most effective method for measuring the surface area of limb is the paper replacement method.

• Nuclear Engineering and Technology
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• v.37 no.6
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• pp.605-610
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• 2005

A method to estimate the relative sensitivity of a self-powered rhodium detector for an upcoming cycle is developed by combining the rhodium depletion data from a nuclear design with the site measurement data. This method can be used both by nuclear power plant designers and by site staffs of Korean standard nuclear power plants for determining which rhodium detectors should be replaced during overhauls.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.818-820
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• 1993

In the three phase full-wave thyristor rectifier, heat radiation concentrated at a few thyristor(s), while equipment's output is normal. That is very important on the predictive maintenance or checking including replacement of parts(or modules). Therefore, this report explains the method of effective diagnosis and the reason that firing control modules have to be adjusted accuratly on each phase.