• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.256-261
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• 2004

Due to the problems of global warming, the frequency of meteorological extremes such as droughts, floods and the annual rainfall amount are suddenly increasing. Even though the increase of greenhouse gases, for example, is thought to be the main factor for global warming, its impact on global climate has not yet been revealed clearly in rather quantitative manners. Therefore, tile objective of this study is to inquire the change of precipitation condition due to climate change by global warming. In brief, this study want to see its assumption if rainfall quantile estimates are really changing. In order to analyze the temporal change, the rainfall quantile estimates at the Seoul rain gauge stations are estimated for the 21-year data period being moved from 1908 to 2002 with 1-year lag. The main objective of this study is to analyze the variability of rainfall quantile estimates using four methods. Next, The changes in confidence interval of rainfall quantile are evaluated by increasing the data period. It has been found that confidence interval of rainfall quantile estimates is reduced as the data period increases. When the hydraulic structures are to be designed, it is important to select the data size and to re-estimate the flood prevention capacity in existing river systems.

• Journal of the military operations research society of Korea
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• v.6 no.1
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• pp.93-101
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• 1980

An effectively designed budget system in the poor resources environment necessarily has three design criteria : (i) to be both planning-oriented and control-oriented, (ii) to be both rationalistic and realistic, (iii) to be sensitive to the variations of resources environment. PPB system is an extreme (planning-oriented and rationalistic) and conventional OEB/OUB system is the other extreme (control-oriented and incrementalistic). Generally, the merits of rationalism are limited because of the infeasibility of applications. Hence, mixtures of the two extremes such as MBO, ZBB, and RZBB have been examined and applied during the last decade. The classical mathematical models of capital budgeting are the starting points of the development of the Budget-Mix Model introduced in this paper. They are modified by the followings: (i) technological-resource constraints, (ii) bounded-variable constraint, (iii) the exchange rules. Special emphasis is laid on the above (iii), because we need more efficient interresource exchanges in the budget-mix process. The Budget-Mix Model is not based on optimization, but a heuristic approach which assures a satisficing solution. And the application fields of this model range between the incremental Nonzero-Base Budgeting and the rational Zero-Base Budgeting. In this thesis, the author suggests 'the budget- mix concept' and a budget-mix model. Budget-mix is a decision process of making program-mix and resource-mix together. For keeping this concept in the existing organization realistic, we need the development of quantitative models describing budget-mix situations.

• Korea journal of population studies
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• v.14 no.1
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• pp.35-46
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• 1991

Improvements in various health indices have been ushered in, along with soaring economic growth in the last few decades in Korea. Life span of Koreans at present stands at somewhere around age of seventies. It seems of worth to elucidate some facets of health profile of historic Koreans during Yi dynasty encompassing about five hundreds years between the 14th and 19th century. Datas on health of historic Koreans are meager with exception for sovereigns for whom royal archives have been preserved intact through centuries. Though the health environments for monarchs are, no doubt, incomparable to that of the grassroot levels during the same period, health profile of monarchs would facilitate to assess health indices for historic Koreans during Yi dynasty. Arithmetic average of life span of 25 consecutive Kings(omitted the last two Kings under Japanese control) is 44.6 years of age 81 year old for King Yongjo and 16 year old for King Danjong, representing two extremes. The principal causes of death are septicemia, subsequent to infections of soft tissue and ether organs(8 in number, one-thirds of all). Secondly, both epidemic disease and vascular accidents caused deaths of three Kings each. Two kings succumbed to diabets and one suicide. The causes for the remainder, eight kings are hardly ciarified. The monarchs who contributed in establishment of new Yi dynasty with highspirited and disciplined survied beyond their fifties and sixties. In contrast, those who reigned during mid - era of the dynasty at its culmination succumbed to death in their young adulthood, most likely due to their indulgence in court life.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.1-9
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• 2017

The Pertamina Energy Tower (PET) and Manhattan West North Tower (MWNT) are two supertall towers recently designed and engineered by Skidmore, Owings & Merrill (SOM). The structural system for both buildings consists of an interior reinforced concrete core and a perimeter moment frame system, which is primarily structural steel. As is typical for tall towers with both concrete and steel elements, staged construction analysis was performed in order to account for the long term effects of creep and shrinkage, which result in differential shortening between the interior concrete core and steel perimeter frame. The particular design of each tower represents two extremes of behavior; PET has a robust connection between the perimeter and core in the form of three sets of outriggers, while the perimeter columns of MWNT do not reach the ground, but are transferred to the core above the base. This paper will present a comparison of the techniques used during the analysis and construction stages of the design process with the goal of understanding the differences in structural behavior of these two building systems in response to the long term effects of creep and shrinkage. This paper will also discuss the design and construction techniques implemented in order to minimize the differential shortening between the interior and exterior over the lifespan of these towers.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.64-73
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• 1996

The three-dimensional strength behavior of compacted decomposed granite soil was studied using cubical triaxial tests with independent control of the three principal stresses. All specimens were loaded under conditions of principal stress direction fixed and aligned with the directions of compacted plane. For comparable test conditions, the major principal strain and volume strain to failure were smallest when the major principal stress acted perpendicular to the compacted plane. The opposite extremes were obtained when the major principal stress acted parallel to the compacted plane. In cubical triaxial tests with same b values and with ${\theta}$ values in one of three sectors of the octahedral plane, independent of the range of ${\theta}$, higher friction angles are obtained in tests with b greater than in triaxial compression tests in which b 0.0, Comparison between the results of the drained cubical triaxial tests on lksan compacted decomposed granite soil and the cross section of the Mohr-Coulomb failure surface as well as the cross section of the Mohr-Coulomb failure surface were made. Lade's isotropic failure criterion based on vertical specimens overestimates the strengths for tests performed with values of 0 between 90˚ and 1 50˚ the Mohr-Coulomb criterion generally underestimates the strengths of tests performed with values of ${\theta}$ between $0^{\circ}$ and $180^{\circ}$ except around the $120^{\circ}$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.633-634
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• 2006

The aim of present work is to link geometrical parameter of maximum area of structural defect $\sqrt{area}\;_{max}$ (proposed by Y. Murakami, 1983) with surface fatigue mechanisms. Determined relations allow making predictions of surface fatigue properties of cemented carbides (WC-Co hardmetal - H15 - 85wt% WC and 15wt %Co, TiC-based cermets - T60/8 - 60wt %TiC and Fe/8wt% Ni and T70/14 - 70wt %TiC and Fe/14wt% Ni) in conditions of rolling contact and impact cycling loading. Pores considered being equivalent to small defects. Three comparative defects conditions are distinguished: surface pore, just below free surface and interior pores. The Vickers hardness of binder (as main responsible for the fracture mechanism of hardmetal and cermets) assumed to be the basis of such assumption. The estimate of this prediction has been done by analyzing the pore sizes using the statistics of extremes. The lower bound of fatigue properties can be correctly predicted by considering the maximum occurring pore size.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.1
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• pp.22-27
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• 2006

Many aspects of climate have been observed to be increasingly volatile during the past several decades. Episodic climate change is not considered to be uncommon. However, there are substantial environmental, social, and economic impacts associated with climate variability that can be managed if the climate and its impacts are properly understood. Plants and natural communities exhibit several types of adaptive strategy to climate change. There is ample reason to relate increasingly erratic weather with a warming climate. Historic climate extremes, the adaptive mechanisms plants exhibit, and how people have (or have not) responded with strategically sound concepts and policy to facilitate a sustainable environmental ethic are reviewed with a vision of international needs and economic stability.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.38-38
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• 2012

The East Asia (EA) region including China, Taiwan, Japan, and Korea are especially vulnerable to hydrometerological extremes during the boreal summer (June-September). This study, therefore, pursued an exploratory analysis to improve better understanding of the potential impacts of the two types of PJ patterns on WNP Tropical cyclone (TC) activities and TC-induced extreme moisture fluxes over Korea's five major river basins. This study shows that during positive PJ years, the large-scale atmospheric environments are more favorable for the TC activities than those in negative PJ years. During positive PJ year, it is found that there are weaker wind shear, stronger rising motion, as well as large relative humidity over the Korean peninsula (KP) compared to negative PJ years. As a result, TCs making landfall are more exhibited over the southeastern portions of South Korea. Despite the relatively modest sample size, we expect that insights and results presented here will be useful for developing a critical support system for the effective reduction and mitigation of TC-caused disasters, as well as for water supply management in coupled human and natural systems.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.39-39
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• 2015

극치 수문(Hydrologic extremes)분야에서는 수문자료의 분포에 따라 Gumbel, GEV, 그리고 GLO 분포와 같은 다양한 확률통계 분포형이 존재한다. GEV와 GLO 분포형의 경우 Gumbel 분포형과 달리 형상매개변수가 포함된 3변수 분포형으로써 이상 기후 현상으로 인한 잦은 극치 수문사상을 표현하는데 좀 더 유연한 것으로 알려져 있다. 특히 GLO 분포형의 경우 영국에서 홍수빈도해석 시 적정분포형으로 선정된바 있다(Institute of Hydrology, 1999). 다양한 분포형 중에서 표본 자료를 대표할 수 있는 분포형을 선정하는 통계적 기법이 적합도 검정이다. 적합도 검정에는 $x^2$-검정, Cramer von-Mises 검정, Kolmogorov-Smirnov 검정, PPCC(probability plot correlation coefficient, 확률도시 상관계수)검정 등이 있으며 그 중 PPCC 검정은 이용방법이 간편하면서도 뛰어난 기각능력을 보이는 것으로 알려져 있다. 본 연구에서는 극치 수문분야에서 널리 이용되고 있는 GLO 분포형을 대상으로 자료의 왜곡도 영향을 고려할 수 있는 확률도시 상관계수 검정의 검정통계량을 추정하여 보았다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.228-232
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• 2017

Extreme hydrological events can cause serious threats to the society. Hence, the selection of probability distributions for extreme rainfall is a fundamental issue. For this reason, this study was focused on understanding possible distributional changes in annual daily maximum rainfalls (AMRs) over time in Sri Lanka using quantile regression. A simplified nine-category distributional-change scheme based on comparing empirical probability density function of two years (i.e. the first year and the last year), was used to determine the distributional changes in AMRs. Daily rainfall series of 13 station over Sri Lanka were analyzed for the period of 1960-2015. 4 distributional change categories were identified for the AMRs. 5 stations showed an upward trend in all the quantiles (i.e. 9 quantiles: from 0.05 to 0.95 with an increment of 0.01 for the AMR) which could give high probability of extreme rainfall. On the other hand, 8 stations showed a downward trend in all the quantiles which could lead to high probability of the low rainfall. Further, we identified a considerable spatial diversity in distributional changes of AMRs over Sri Lanka.