• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3B
• /
• pp.257-267
• /
• 2010

A flood event can be characterized by three attributes such as peak discharge, total flood volume, and flood duration, which are correlated each other. However, the amount of peak discharge is only used to evaluate the flood events for the hydrological plan and design. The univariate analysis has a limitation in describing the complex probability behavior of flood events. Thus, the univariate analysis cannot derive satisfying results in flood frequency analysis. This study proposed bivariate flood frequency analysis methods for evaluating flood events considering correlations among attributes of flood events. Parametric distributions such as Gumbel mixed model and bivariate gamma distribution, and a non-parametric model using a bivariate kernel function were introduced in this study. A time series of annual flood events were extracted from observations of inflow to the Soyang River Dam and the Daechung Dam, respectively. The joint probability distributions and return periods were derived from the relationship between the amount of peak discharge and the total volume of flood runoff. Applicabilities of bivariate flood frequency analysis were examined by comparing the return period acquired from the proposed bivariate analyses and the conventional univariate analysis.

• Journal of Korea Water Resources Association
• /
• v.55 no.6
• /
• pp.405-419
• /
• 2022

Flood frequency analysis commonly used to design the hydraulic structures to minimize flood damage includes uncertainty. Therefore, the most appropriate design flood within a uncertainty should be selected in the final stage of a hydraulic structure, but related studies were rarely carried out. The total expected cost function introduced into the flood frequency analysis is a new approach for determining the optimal design flood. This procedure has been used as UNCODE (UNcertainty COmpliant DEsign), but the application has not yet been introduced in South Korea. This study introduced the mathematical procedure of UNCODE and calculated the optimal design flood using the annual maximum inflow of hydroelectric dams located in the Bukhan River system and results were compared with that of the existing flood frequency. The parameter uncertainty was considered in the total expected cost function using the Gumbel and the GEV distribution, and the Metropolis-Hastings algorithm was used to sample the parameters. In this study, cost function and damage function were assumed to be a first-order linear function. It was found that the medians of the optimal design flood for 4 Hydroelectric dams, 2 probability distributions, and 2 return periods were calculated to be somewhat larger than the design flood by the existing flood frequency analysis. In the future, it is needed to develop the practical approximated procedure to UNCODE.

• Journal of Service Research and Studies
• /
• v.6 no.1
• /
• pp.83-95
• /
• 2016

We examine the information transmission between the Service Industrial Production Index and the Service Industrial Wholesale and Retail Index, based on the returns data offered by the Korea Bank. The data includes daily return data from January 2000 to September 2015. Utilizing a dynamic analytical tool-the VAR model, Granger Causality test, Impulse Response Function and Variance Decomposition have been implemented. The results of the analysis are as follows. Firstly, results of Granger Causality test suggests the existence of mutual causality the Service Industrial Production Index precede and have explanatory power the Service Industrial Wholesale and Retail Index However the results also identified a greater causality and explanatory power of the Service Industrial Wholesale and Retail Index over the Service Industrial Production Index. Secondly, the results of impulse response function suggest that the Service Industrial Production Index show immediate response to the Service Industrial Wholesale and Retail Index and are influenced by till time 5 From time 2, the impact gradually disappears. Also the Service Industrial Wholesale and Retail Index show immediate response to the Service Industrial Production Index and are influenced by till time 2.5, the impact gradually disappears. Lastly, the variance decomposition analysis shows that the changes of return of Service Industrial Production Index are dependent on those of the Service Industrial Wholesale and Retail Index. This implies that returns on the Service Industrial Production Index have a significant influence over returns on the Service Industrial Wholesale and Retail Index. It contributes to the understanding of market price formation function through analysis of detached the Service Industrial Production Index and Service Industrial Wholesale and Retail Index. Finally, our results can be used as a guide by the Korea Bank and Republic of Korea and as well as Statistics Korea.

• Journal of Bio-Environment Control
• /
• v.25 no.2
• /
• pp.133-137
• /
• 2016

'Sinano Sweet' apple trees were defoliated at intervals of a month from May to October to simulate damage occured by hail and typhoon in Korea, accordingly fruit yield, reserve accumulations and return bloom were investigated. As the more severe defoliation degree was and earlier defoliation time was, fruit weight and fruit yields were more decreased. Fruit weight and yields of 30% defoliated trees, regardless of the defoliation time, showed no significant difference with those of control. Because carbohydrate contents of the 2-year old branches defoliated before August were even lower than those of branches defoliated after September, it was considered that defoliation time is more effective on the carbohydrate content than defoliation degree. Among the trees defoliated before August, 50% defoliated trees at August contained the lowest carbohydrate by 50% of control. Time and degree of defoliation had an effect on the number of flower buds following year. The number of return bloom in trees defoliated from May to July was decreased by delay of defoliation time and was the lowest in trees defoliated at July. On the other hand, it was not have a significant different between control and trees defoliated since August. Relationship between the number of return bloom and carbohydrate reserves showed positive correlation. As a result, it is considered that fruit thinning, when defoliation occurred in the growing season, needs for strengthening the sink function of remained individual fruit effect on fruit enlargement and for increaseing the carbohydrate reserve effect on return bloom.

• Journal of Service Research and Studies
• /
• v.5 no.1
• /
• pp.91-103
• /
• 2015

We examine the information transmission between the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index, based on the returns data offered by the Korea Exchange. The data includes daily return data from 1 January 2012 to 31 December 2014. Utilizing a dynamic analytical tool-the VAR model, Granger Causality test, Impulse Response Function and Variance Decomposition have been implemented. The results of the analysis are as follows. Firstly, results of Granger Causality test suggests the existence of mutual causality the KT Futures Index and the SK Telecom Futures Index precede and have explanatory power the KT Spot and the SK Telecom Spot However the results also identified a greater causality and explanatory power of the KT Spot and the SK Telecom Spot over the KT Futures Index and the SK Telecom Futures Index. Secondly, the results of impulse response function suggest that the KT Futures Index show immediate response to the KT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Also the SKT Futures Index show immediate response to the SKT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Lastly, the variance decomposition analysis shows that the changes of return of the KT Spot and SKT Spot are dependent on those of the KT Futures Index and the SK Telecom Futures Index. This implies that returns on the KT Spot and SKT Spot have a significant influence over returns on the KT Futures Index and the SK Telecom Futures Index. It contributes to the understanding of market price formation function through analysis of detached the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index.

• Journal of Korea Technology Innovation Society
• /
• v.11 no.2
• /
• pp.241-263
• /
• 2008

Within any income approach, a discount rate is used to convert some projected free cash flow to its presented value. In case of valuing companies, the most frequently used discount rate is the weighted average cost of capital(WACC) at the aggregate level. But technology valuation is different to discounting aggregate corporate cash flow since it is concerned about individual Intellectual property. Therefore, blindly applying standard discount rate such as WACC in technology valuation is unlikely to lead to the right result. The primary focus of this paper is to establish the structure of discount rate for technology valuation and to suggest the method of estimation. To determine an appropriate discount rate for technology valuation, the level of technology risk, market risk and competitive risk should be included in the structure of discount rate. This paper suggests the build-up model which consists of three components as a expansion of the CAPM. It includes (1) a risk-free rate of return, (2) general market risk premium and beta and (3) intellectual property risk premium related to technology risk and specific target market risk. However, there is no specific check list for examining the intellectual property risk until now and no specific method for quantifying its risk into risk premium. This paper developed the 10 element to determine the level of the intellectual property risk and applied estimation function such as linear function, natural log function and exponential function to transform the level of risk into risk premium. The limitation of this paper is that the range of intellectual property risk premium is inferred based on the information of foreign and domestic valuation agency. Finally, this paper explored the development of an intellectual property discount rate for technology valuation and presented the method in order to quantify the intellectual property risk premium.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.34 no.4
• /
• pp.290-298
• /
• 2014

Ultrasonic thickness measurement is a non-destructive method to measure the local thickness of a solid element, based on the time taken for an ultrasound wave to return to the surface. When an element is very thin, it is difficult to measure thickness with the conventional ultrasonic thickness method. This is because the method measures the time delay by using the peak of a pulse, and the pulses overlap. To solve this problem, we propose a method for measuring thickness by using the power cepstrum and the minimum variance cepstrum. Because the cepstrums processing can divides the ultrasound into an impulse train and transfer function, where the period of the impulse train is the traversal time, the thickness can be measured exactly. To verify the proposed method, we performed experiments with steel and, acrylic plates of variable thickness. The conventional method is not able to estimate the thickness, because of the overlapping pulses. However, the cepstrum ultrasonic signal processing that divides a pulse into an impulse and a transfer function can measure the thickness exactly.

• Korean Journal of Organic Agriculture
• /
• v.24 no.4
• /
• pp.665-680
• /
• 2016

Theoretically, it is said that economies of scope can be realized in the cropelivestock cycling organic farming. Thus, it is also used as the principle of organic farming. However, it is difficult to find the cases of the empirical analysis of it in Korea. In that sense, this study is meaningful in that it analyzed the agricultural data of case farms of obtaining the approval of both organic agricultural products and organic animal products and practicing cycling farming for 4 years and tested the hypothesis. This study measured economies of scope by using the actual measurement value and estimation value farming performance statistics for 4 years of case farms. This farmhouse conducted nutrient cycling in the farm like self-manufacturing and injecting organic agricultural byproduct and wild grass as organic livestock feed and fermenting organic livestock manure to organic compost to return it 100%. The results can be summarized as follows: According to the result of cycling farming of combining and producing organic agriculture and organic livestock, economies of scope were found to be realized in this case farmhouse. That is, although not strong, EOS>0, there were economies of scope. The measurement value appeared as 0.0722, 0.00378, 0.04667 and 0.13127 in 2012, 2013, 2014 and 2015, respectively. It was improved as time passes and the scale gets smaller. Therefore, in order to further improve economies of scope, there should be measures of reducing duplication costs between agriculture-livestock as low as possible and lowering the production cost of organic feed. That is, there is a need for the management strategy to adjust the import function and cost function according to the change in management paradigm and cropping system.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.9 no.1
• /
• pp.59-68
• /
• 2005

Background and purpose: Cardiovascular disease will undoubtedly rise along with the aging of the 'baby-boom' generation. The purpose of this study is to find the new index of the cardiovascular aging. Methods: The effects of aging on the heart and the arterial system are surveyed in the point of structure and function. Results: Arterial stiffening is due to the fatiguing effects of periodic stress on the arterial wall and is the main reason for increasing pulse wave velocity. The systolic hypertension is caused by the early return of wave reflection. The increased after-load by the arterial change leads to the development of left ventricular hypertrophy. The reduction in left ventricular compliance cause the impairments of the diastolic function. In contrast to the lower limb, aging effect in the upper limb are almost due to the ascending aortic pressure wave and the reflected wave from the lower limb. Conclusion: We have the following points. (1) The change of physiological pulse pattern by age can be explained by the early returning of reflected wave. (2) The atrial pulse in old age are generated by the left ventricular hypertrophy.

• Archives of Plastic Surgery
• /
• v.38 no.6
• /
• pp.829-835
• /
• 2011

Purpose: The two major concerns in skin grafting are poor color match in the recipient site and the donor site morbidity. And, glabrous skin on the palmar aspect of the hands and plantar aspect of the feet attributes define the skin on the palm and fingers sole as functionally and aesthetically different from skin on other parts of the body. When there is a glabrous skin defect, it should be replaced with similar skin to restore function and aesthetics. The palmar crease areas were used to minimize these problems. The purpose of this study is to present the precise surgical technique of the full thickness skin graft using distal palmar and midpalmar creases for aesthetic better outcome for hand injuries. Methods: From May 2006 to April 2010, 10 patients with 11 defects underwent glabrous full thickness skin grafting of finger defects. Causes included seven machinery injuries, two secondary burn reconstructions, and one knife injury. Donor sites included ten glabrous full thickness skin graft from the distal palmar crease and one from the midpalmar crease. Results: Follow-up ranged from 3 months to 24 months. All glabrous skin grafts demonstrated complete taking the recipient sites and no incidence of the complete or partial loss. The donor site healed without complications, and there were no incidences of significant hypopigmantation, hyperpigmentation, or hypertrophic scarring. Conclusion: The important aspects of this method involve immediate return of glabrous skin to the defect site and restoration of the recipient site's crease by simple primary closure from adjacent skin. The glabrous skin of the palm provides the best tissue match for the reconstruction of the hands, but only a limited amount of tissue is available for this purpose. Full thickness skin grafting using palmar crease of the defects is the ideal way of reconstructing glabrous skin to restore both function and aesthetics and minimize donor site morbidity.