• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.279-287
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• 2005

In this study, I suggest an effective operation of waterwork facilities in large cities and a scientific method for utilizing water in water distribution systems. To achieve this goal, my simulation were carried out on data from Kwangju City using Pipenet '98, a pipe-network program. From this simulation, I examine the possibilities of application the system in large cities, comparing data measured at 33 hydraulic pressure monitoring places from waterwork enterprises. The result is coincident with that of waterwork enterprises, with about a 12.5% average error rate and $0.32kg/cm^2$ average deviation. The method and program I use here can be helpful in cities where there is a need to extend the waterwork facilities, or where there is a need to suspend the water supply, and/or there is an accident. The simulation shows how to expand waterwork facilities effectively, how to prevent accidents, and how to estimate the hydraulic pressure even in the areas without monitoring places.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.49.1-49.1
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• 2019

I present the mean metallicity distribution of stars in the Milky Way based on photometry from the Sloan Digital Sky Survey. I utilize an empirically calibrated set of stellar isochrones developed in previous work to estimate the metallicities of individual stars to a precision of 0.2 dex for reasonably bright stars across the survey area. I also obtain more precise metallicity estimates using priors from the Gaia parallaxes for relatively nearby stars. Close to the Galactic mid-plane (|Z| < 2 kpc), a mean metallicity map reveals deviations from the mirror symmetry between the northern and southern hemispheres, displaying wave-like oscillations. The observed metallicity asymmetry structure is almost parallel to the Galactic mid-plane, and coincides with the previously known asymmetry in the stellar number density distribution. This result reinforces the previous notion of the plane-parallel vertical waves propagating through the disk, which have been excited by a massive halo substructure such as the Sagittarius dwarf galaxy plunging through the Milky Way's disk. This work provides evidence that the Gaia phase-space spiral may continue out to |Z| ~ 1.5 kpc.

• Journal of Distribution Science
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• v.6 no.1
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• pp.25-46
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• 2008

The latest flow in Korea's distribution market is characterized by the deterioration of small/medium distribution market due to the rapid growth of multinational discount stores. As various multinational discount stores have merged with Korean discount stores (Homever acquired Carrefour and E-Mart acquired Wal-Mart), these discount stores have enlarged in size and dominated the market. On the contrary, small/medium distributors with relatively weak infrastructures are losing competitiveness in the market. Traditional marketplaces in local areas, in particular, are facing a serious crisis as they are neglected in the depressed local markets and have been beaten by the increasing discount stores and the diversifying distributors. The purpose of this study was to propose alternative plans to revitalize traditional marketplaces that are endangered by the unbalanced development of the distribution industry. This study analyzed the distribution performances and problems of Daejeon Metropolitan City and used the analysis to point out the problems specific to traditional marketplaces and propose a way to revitalize them. I hope that this study can help discount stores and small/medium distributors find balance in the market, and give traditional marketplaces the competitiveness to pursue sustainable growth.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.516-518
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• 2000

This paper presents a methodology for effective control of fuel cell devices connected to the electric utility distribution network. A controller is designed for a fuel cell power plant to assist the conventional generators to damp out oscillations, which is possible by utilizing the fast response characteristic of fuel cells. Computer model of the controller is proposed and its effectiveness is proved by a sample test. Fuel cell devices can be used to improve power system stability when these are connected to a distribution system.

• The Journal of the Korean dental association
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• v.25 no.12 s.223
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• pp.1145-1156
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• 1987

The purpose of this experimental study was to analyze the stress distribution from fixed partial dentures to the surrounding structures. This study was carried out on the experimental bridges with K-L blade, F.D.B.I.-11 type, F.D.B.I.-21 type, shape-memory metal blade and two-Apacerams as posterior abutment. The stress patterns and fringes were observed through the circular transmission polariscope. The results of this study were obtained as follows: 1. The stress was more concentrated to the roots apex than the implants. 2. In all blade implants, the stress was more concentrated to the distal side than the mesial side. 3. F.D.B.I.-11 type was more stress concentrated than the 21 type. 4. Shape-memory metal blade was the most effective for stress distribution. 5. Apacerams were more stress concentrated than the blde types and in the model of Apaceram with rubber-ring, anterior root was tipped distally.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.646-652
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• 2006

This study identifies the comparison of Technical specification and Characteristics of DC Protection Relay(ETCPU200) used in DC Distribution System in Korea. ETCPU200 has completed Field Test and approved its capability by finding out causes of recent operations through lately developed digital DC protection relay in parallel operation at Maebong-Substation, Sangbong-Substation, Nakseongdae-Substation, Euljirosaga-Substation, Jegi-Substation and Chongyangri T/P area. It also examines additional features for efficient System Analysis and Operations.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.167-175
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• 2004

A nonparametric procedure is proposed to test the exponentiality against the hypothesis that one life distribution has a greater residual life times than the other life distribution. Such a hypothesis turns out to be equivalent to the one that one failure rate is greater than the other and so the proposed test works as a competitor to more IFR tests by Kochar (1979, 1981) and Cheng (1985). Our test statistic utilizes the U-statistics theory and a large sample nonpara metric test is established. The power of the proposed test is discussed by calculating the Pitman asymptotic relative efficiencies against several alter native hypotheses. A numerical example is presented to exemplify the proposed test.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1285-1289
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• 2008

Increasing the flood control capacity's link that is enforcing to existing dam by unusual change of weather, While build planing construction by exiting spillway of tunnel type to dam, could know that part bed rock is formed as is different with design. Grasped topography of research area and geology state to definite distribution aspect of different bed rock, Place that achieved Surface geological Survey and correct Survey is difficult in some section enforced Electrical resistivity dipole-dipole investigation. Grasped stratigraphy distribution confirmation and fracture or weathering zone making out siding 2D-Resistivity Electrical resistivity diagram and Reverse analysis diagram, examining closely soil weathered rock rock's distribution state, established stability countermeasure plan

• Communications for Statistical Applications and Methods
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• v.29 no.3
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• pp.373-391
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• 2022

The distribution of observations in most econometric studies with spatial heterogeneity is skewed. Usually, a single transformation of the data is used to approximate normality and to model the transformed data with a normal assumption. This assumption is however not always appropriate due to the fact that panel data often exhibit non-normal characteristics. In this work, the normality assumption is relaxed in spatial mixed models, allowing for spatial heterogeneity. An inference procedure based on Bayesian mixed modeling is carried out with a multivariate skew-elliptical distribution, which includes the skew-t, skew-normal, student-t, and normal distributions as special cases. The methodology is illustrated through a simulation study and according to the empirical literature, we fit our models to non-life insurance consumption observed between 1998 and 2002 across a spatial panel of 103 Italian provinces in order to determine its determinants. Analyzing the posterior distribution of some parameters and comparing various model comparison criteria indicate the proposed model to be superior to conventional ones.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.45-51
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• 2005

The distribution of shaft resistance is measured by the static load test with the strain gauge or stress gauge, so that the long-term load distribution must be considered for the pile design. However, the measurement by strain gauge generally assumes the 'zero reading', which is the reading taken at 'zero time' with 'zero' load and the residual stress, which is the negative skin friction(or the negative shaft resistance) caused by the pile construction, is neglected. Therefore, the measured value by strain gauge is different from the true load-distribution because residual stresses were neglected. In this study, the three drilled shafts were constructed, and the strain measurements were carried out just after shaft construction. As a result of this study, it is shown that the true load-distribution of drilled shaft is quite different with known load distribution and the true load-distribution of drilled shaft changed from the negative skin friction to the positive skin according to the load increment.