• Water for future
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• v.19 no.2
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• pp.139-148
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• 1986

The hydrologic response function in a small basin is expressed by the distribution function of slope length. The characteristics of topographical factors is represented to the concentration time, and the instantaneous unit hydrograph is derived as a hydrologic rsponse function by application of probobility density function. The averaging process of runoff characteristics within watershed was analyzed for a few small watershed where was split up the small basin itself. The method of calculation of the effective rainfall should play important roles in the transformation process from hydrologic response function to runoff hydrograph. In this paper, the Horton's infiltration quation is used as a method of calculation of effective rainfall, a new response function of runoff process is derived. The $\Phi$-index method and the infiltration method are tested by comparing the observed and estimated values.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.134-137
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• 2008

A methodology to evaluate the performance analysis for small hydropower at existing water treatment facilities has been studied. It consists of two main parts; flow duration function which can describe existing water treatment facilities and performance analysis to estimate the output characteristics of small hydro power plants. The output performance characteristics for Mi-ho reservoir, Sum-kang low dam, Sun-cheon sewage treatment plant and Nam-dong purification plant were analyzed, using developed model. According to the simulation results, the predicted data show that the data were in good agreement with measured results. Also, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power at existing water treatment facilities.

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1159-1171
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• 2017

The purpose of this paper is twofold. The first is to show that two meromorphic functions f and g must be linked by a quasi-$M{\ddot{o}}bius$ transformation if they share a pair of small functions regardless of multiplicity and share other three pairs of small functions with multiplicities truncated to level 4. We also show a quasi-$M{\ddot{o}}bius$ transformation between two meromorphic functions if they share four pairs of small functions with multiplicities truncated by 4, where all zeros with multiplicities at least k > 865 are omitted. Moreover the explicit $M{\ddot{o}}bius$-transformation between such f and g is given. Our results are improvement of some recent results.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.161-166
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• 2011

This paper proposes an algorithm for determining critical generator lists using accelerating power and synchronizing power coefficient (SPC), and critical generator group (CGG) from CGG candidates, which is a combination of critical generators. The accurate determination of CGG provides a more accurate energy margin while providing system operator with information of possible unstable generator group. Classical transient energy function (TEF) method selects the critical generators with big corrected kinetic energy of each generator at the moment of fault removal. However, the generator with small acceleration after fault, that is, the generator with small corrected kinetic energy, is also likely to belong to CGG if the generator has small synchronizing power. The proposed algorithm has been verified to be effective compared with the classical TEF method. We utilized the power system of Korean Electric Power Corporation(KEPCO) as a test system.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.1
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• pp.3-10
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• 2017

This study is to analyze the remodeling method of library in terms of space extension method and urban regeneration by repurposing function in unused facilities through case study. In many case of library extension, horizontal extensions are more frequent than vertical extensions, because there are limits to extend vertically due to high live load estimation by book stacks. Extension schemes was organized by new building extension method in connection with existing buildings, attaching method small scaled mass or linear mass to existing building, connecting method a plurality of existing small buildings, vertical extension method on the top of the structure, underground extension method using special structure. Unused facility remodeling to the library, large scaled buildings can be developed completely to the function of the library through the relocation of the space, while small scaled building needs spatial extension. In the case of spatial extension, existing space that was used for other purposes can be used as a reading room or office, avoiding high live load estimation.

• Kyungpook Mathematical Journal
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• v.49 no.2
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• pp.235-243
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• 2009

In this paper, we deal with the problem of uniqueness of meromorphic functions that share two small functions with their derivatives, and obtain the following result which improves a result of Yao and Li: Let f(z) be a nonconstant meromorphic function, k > 5 be an integer. If f(z) and g(z) = $a_1(z)f(z)+a_2(z)f^{(k)}(z)$ share the value 0 CM, and share b(z) IM, $\overline{N}_E(r,f=0=F^{(k)})=S(r)$, f${\equiv}$g, where $a_1(z)$, $a_2(z)$ and b(z) are small functions of f(z).

• Journal of Integrative Natural Science
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• v.5 no.3
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• pp.157-162
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• 2012

Measurement error is one of main source of error in survey. It is generally defined as the difference between an observed value and an underlying true value. An observed value with error may be expressed as a function of the true value plus error term. In some cases, the measurement error variance may be also a function of the unknown true value. The error variance function can be rewritten as a function of true value multiplied by a scale factor. This research explore methods for estimation of the measurement error variance based on the data from complex sampling design. We consider the case in which the variance of mesurement error is a linear function of unknown true value, and the error variance scale factor is small. We applied our results to the U.S. Third National Health and Nutrition Examination Survey (the U.S. NHANES III) data for empirical analyses, which has replicate measurements for relatively small subset of initial respondents's group.

• East Asian mathematical journal
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• v.39 no.5
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• pp.537-547
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• 2023

In this paper, we introduce the optimal approximation by a Gaussian function for a probability density function. We show that the approximation can be obtained by solving a non-linear system of parameters of Gaussian function. Then, to understand the non-normality of the empirical distributions observed in financial markets, we consider the nearly Gaussian function that consists of an optimally approximated Gaussian function and a small periodically oscillating density function. We show that, depending on the parameters of the oscillation, the nearly Gaussian functions can have fairly thick heavy tails.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.467-475
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• 2014

This study was performed to estimate optimum fishing mortality (F) and the age at first capture ($t_c$) for small yellow croaker in Korean waters. We first estimated optimum F and $t_c$ using traditional yield-per-recruit (YPR) analysis, and the results were 0.8/year and 2.5 years old, respectively. However, the individual fish price per unit weight of small yellow croaker in Korea increases dramatically by size. Thus, we developed an alternative method, which is called as production value-per-recruit (PPR) analysis. We developed two types of the PPR analysis, that is, the discrete function and the continuous function method. We estimated optimum F and $t_c$ using the two types of the PPR analysis and compared the results. The optimum F and $t_c$ from the discrete function method, were 0.3/year and 5.0 years old, respectively, while those from the continuous function method were 0.5/year and 3.5 years old, respectively. These PPR estimates were much more conservative for the stock management than the traditional YPR analysis, which can prevent the fish stock from the economic overfishing. As a result, the PPR analysis could be more proper approach for stock assessment in the case that the individual fish price per unit weight increases dramatically by size like small yellow croaker in Korea.

• Applied Microscopy
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• v.22 no.1
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• pp.15-32
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• 1992

This study was an attempt to investigate and compare the fine structure of small cells in the space of Disse of various animal livers. All animal livers contained small cells with or without lipid droplets and the one with lipid droplet seemed to be more developed and show an abundance of activity in function. The fine structure of the small cells observed in the nonmammals was similar to that of Ito cell in the mammal. The electron density of the small cells was similar to that of other cell types in the same animal liver. The cisternal dilation of rough endoplasmic reticulum and Golgi apparatus was more predominant in the mammalian Ito cells. In the nonmammalian, aquatic vertebrates, however, lysosomes and filaments are much more abundant in the Ito cell and its abundant cytoplasmic processes rich in filaments were usually extended between the parenchymal cells. The disparity in size of organelles and numbers of lipid droplets in the small cells showed a tendency similar to those of other cell types in the same animal. From these results, it is considered that the small cells in the space of Disse is a Ito cell and the Ito cell without lipid droplets differentiates into the one containing lipid droplets according to the characteristics of the different animals respectively, and that the Ito cells in the mammals are more active in metabolic function, while those in the nonmammalian aquatic vertebrates are abundant in support of parenchyme.