• Water for future
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• v.7 no.2
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• pp.107-111
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• 1974

Annual runoff in the Nakdong river basin has been analyzed to find the probability functions of best fit to distribution of historical annual runoff. The results obtained are as follows; (1) Log-normal 3-parameter disrtibution is believed as the probability function of best fit to historical distribution (2) Log-normal 3-parameter disrtibution is believed as the best fit probability function among Log-normal dist-ributions. (3) In the test of goodness of fit, $x^2-test$ shows that probability of $x^2-valus$ in Log-normal 3-parameter distribution is nearly more than 90%. But in the Simirnov-Kolmogorov test, hypotheses for the probability distributions cannot be rejected at significance level 5% & 1%. (4) Among 7 gauging stations, Dongchon & Koryung-Bridge's records show lower fitness to the theoretical probability functions than other 5 gauging station's

• Industrial Engineering and Management Systems
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• v.10 no.2
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• pp.154-160
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• 2011

In this paper, a reliability sampling plan under progressively type-1 interval censoring is proposed when the lifetime of products follows the Pareto distribution of second kind. We use the maximum likelihood estimator for the median life and its asymptotic distribution. The cost model is proposed and the design parameters are determined such that the given producer's and the consumer's risks are satisfied. Tables are given and the results are explained with examples.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.40-45
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• 2010

In order to establish the electric distribution system economically and operate efficiently, it becomes important to calculate energy losses of the system more accurately. This importance is not only related for the engineering of utilities' power network but also for the consumers' electric system. The Distribution Loss Factor (DLF) is the fundamental element of calculating the energy losses occurred through the electric system including the electric lines and equipments. Up to now, the DLF is calculated by empirical formulas using the correlation between the DLF itself and Load Factor. However, these methods have some limitations to reflect the various characteristics of the system and the load. In this regard, the novel method proposed here is developed to yield more accurate result of DLF which actively interacting with the characteristics and load patterns of the system. The improvement of accuracy is very significant according to the results of verification presented at the end of this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1178-1182
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• 2011

The best methods for distribution controled of LED lighting fixtures is control to designed LED chip array, lens and reflector. However, lens design need distribution design to reflector for low-wattage LED lighting because of difficulty of production and reduction of light efficiency. In addition, it needs maximize of thermal performance to improve the efficiency and reliability of device. As a result, for the height of reflector 40[mm] and Inclination 25[$^{\circ}$], we can see the best distribution properties, and, in the thermal properties, junction temperature MCPCB 62.9 [$^{\circ}C$], FR4 PCB 89.6 [$^{\circ}C$], FR4 PCB from Via-hole is 63.1 [$^{\circ}C$]. it may improve for thermal properties for makes the Via-hole.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.472-480
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• 2007

This paper analyzes overvoltage on testing line for various parameter effect examination. Model systems consist of overhead line and underground cable. The model considered actual characteristic data of distribution lines. and will be constructed at testing yard. The simulations were performed under various line configuration such as cable kinds, cable length, lightning wave, lightning wave time, transformer and branch circuits. The simulation models are established by EMTP/ATPDraw and Line Constants are calculated by ATP_LCC. When lightning surge strikes on conductor of overhead line, EMTP/ATPDraw calculates overvoltage in many cases. Simulation results will be compared with real testing results at testing yard. The compared results will be used to establish protection methods in actual underground distribution systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.451-456
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• 2007

This paper presents a problem that reconfigure distribution power system using branch exchange method. Optimal reconfiguration problem calculates line loss, voltage condition about system states of all situations that become different according to line On/off status, and search for optimum composition of these. However, result is difficult to be calculated fast. Because radiated operation condition of system is satisfied using many connection and sectionalize switches in the distribution power system. Therefore, in this paper, optimization method for reducing system total loss and satisfying operating condition of radial and constraints condition of voltage is proposed using the fastest branch exchange. And optimal solution at branch exchange algorithm can be wrong estimated to local optimal solution according to initial operating state. Considering this particular, an initial operating point algorithm is added and this paper showed that optimal solution arrives at global optimal solution.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.465-471
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• 2007

The one step type pole and two step type pole are used in KEPCO's distribution system. The neutral current increases in three-phase four-wire distribution system due to unbalanced load. Usually, power line and communication line are installed at contiguity by effect of topography in Korea. To this end, the damages such as electrostatic induction, electromagnetic induction and harmonic induction generated by induced voltage and current are occured in power line and communication line. This paper calculates the neutral current in KEPCO's distribution system using EMTP by composing various simulated conditions. Also, these results are verified by vector analysis.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.2
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• pp.67-75
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• 2001

This paper presents a fast and effective methodology for service restoration in large-scale distribution systems. The service restoration problem is formulated as a constrained optimization problem and requires the fast computation time and superior solution because the more unfaulted out-of-service area should be restored as soon as possible. The proposed methodology is designed to consider the fast computation time and priority service restoration by dijkstra algorithm and fuzzy theory in large-scale distribution systems. Simulation results demonstrate the validity and effectiveness of the proposed on a 26-bus and 140-bus system.

• Communications for Statistical Applications and Methods
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• v.22 no.3
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• pp.233-239
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• 2015

This study compares two generalized Lindley distributions and assesses consistency between theoretical and analytical results. Data (complete and censored) assumed to follow the Lindley distribution are generated and analyzed using two generalized Lindley distributions, and maximum likelihood estimates of parameters from the generalized distributions are obtained. Size and power of tests of hypotheses on the parameters are assessed drawing on asymptotic properties of the maximum likelihood estimates. Results suggest that whereas size of some of the tests of hypotheses based on the considered generalized distributions are essentially ${\alpha}$-level, some are possibly not; power of tests of hypotheses on the Lindley distribution parameter from the two distributions differs.

• BMB Reports
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• v.32 no.5
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• pp.506-510
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• 1999

The newly-found thiol peroxidases (TPx) with a conserved cysteine as the primary site of catalysis are capable of catalyzing the thiol-dependent reduction of peroxides. However, the cellular distributions of the isoforms remain poorly understood. As a first step in understanding the physiological functions of the TPx isoforms, we examined the cellular and tissue distribution of the isoenzymes in various bovine tissues. The tissue distributions of TPx isoenzymes indicate that two types of TPx are widely distributed throughout all of the tested tissues. These two forms are the predominant proteins, with levels of the proteins being quite different from each other. The level of predominant TPx proteins, named type II (TPx II) and type V (TPx V), appeared to be very different with respect to tissue type. The cellular distribution and level of TPx isoenzymes also varied with the types of cells. Immunoblot analysis of the mitochondrial and cytosol fractions from various tissues indicates that TPx III is a unique mitochondrial form. Based on the different tissue and cellular distribution of TPx isoenzymes, we discuss the physiological function of TPx isoenzymes, especially the ubiquitous TPx II.