• Journal of Distribution Research
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• v.1 no.2
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• pp.115-140
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• 1996

This study analyses the Chinese and the Russian distribution systems comparatively focusing on the economic system. Before the economic transformation both nations were socialistic planned economy. After the economic transformation China is under the socialistic market economy, and Russia under the capitalistic market economy. The purpose of this study is to see how the distribution systems of both nations were changed according to the transformation of economic system. It analyses the relationship between nationalized manufacturing companies and distribution companies, and the national planned distribution of products before the economic transformation of both nations. It examines the privatization of distribution-related companies and the structurally exclusive supply of manufacturing companies in distribution system in Russia after the economic transformation. It also investigates the institutionalized control of nationalized manufaturing companies over distribution companies, and the national intervention of product pricing in China.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.9-18
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• 2002

This study was to observe the occurrence of heterotrophic bacteria in terms of free chlorine residuals in two different water distribution systems belong to both K and Y water treatment plant. The data analyzed in this study showed that in distribution systems(DS), the free chlorine residuals were decreased from 0.10 to 0.56 ㎎/1 for K, and 0.51 and 0.78 ㎎/l for Y The decay of free chlorine were clearly higher in both March and August than those in January. The HPC in DS were ranged from 0 to 40 CFU/ml for K,0 to 270 CFU/ml for Y, on R2A medium. In particular, Its level was relatively high at consumers' ground storage tanks, taps and point-of-end area of Y, The predominant genera found in the distribution systems were Acinetobacter, Sphingomonas (branch of Pseudomonas), Microroccus, Bacillus, Staphylococcus. The diversity of heterotrophic bacteria was increased in the end-point area. Most of them were either encapsulated cells or cocci of gram-positve. In conclusion, the point-of-end area in distribution systems showed that the longer flow distance from WTP the greater diversity and higher level of heterotrophic bacteria due to the significant decay of free chlorine residuals.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.4
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• pp.238-247
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• 2004

This paper describes the insulation coordination scheme of line in distribution system when the direct lightning surge strikes. The BIL that is applied to distribution system is not properly considered the performance and operation of arresters. Because of that, the high BIL is being used at partial system. This paper variously analyses the lightning overvoltage of line and equipment with earth of overhead grounding wire and installation types of arrester. From these result. authors examine the rationality of BIL.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.6-10
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• 1999

We present a simulation result to the analysis of the effects of cell residence time distributions upon the expected channel occupancy time based on an analytic mobility model. Numerical examples show that exponential distribution provides upper and lower bound to the expected channel occupancy times of new calls and handoff calls. This fact reveals that the assumption of exponential distribution as the cell residence time distribution as the cell residence time distribution may over- or under-estimate cellular mobile systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.854-859
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• 2010

Distribution Automation System(DAS) is designed to improve operational efficiency by acquisition and control of remote data using its components such as central computation units, communication network and feeder remote terminal units. A conventional human machine interface of the DAS adopts a schematic diagram which is made by drawing power equipments on the geographic information system map. The single line diagram is more useful than the schematic diagram for the main tasks of distribution system operation such as protective relay coordination, service restoration and loss minimization. Since the configuration of the distribution line is changed according to the relocation of the open tie switches, the auto-drawing algorithm based on the connection between the sections and the switches is an essential technique. This paper proposes a new auto-drawing algorithm for a single line diagram of distribution systems based on tertiary tree and collision avoidance method. The feasibility of the proposed algorithm has been testified for various cases using practical distribution system with 12 feeders.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.811-822
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• 2018

Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

• Environmental Engineering Research
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• v.22 no.4
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• pp.363-368
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• 2017

The external diseconomy is hampering sustainable development of the city logistics sector. Burdens on urban environment imposed by the city logistics industry have been put in the spotlight. Based on the principle of Life Cycle Analysis, the comprehensive environment impact for city logistics systems is measured. Firstly, with the city logistics service chain as a whole, its business processes and their interactions with environment are analyzed. In total four types of major environment impact categories are determined. Secondly, case study is made on three city logistics operators located in Jing-Jin-Ji region of China with different business modes, respectively self-operation mode, joint distribution mode and the $3^{rd}$ Party Logistics or 3PL mode. Through analysis of energy consumption and emissions for various business processes, their comprehensive environmental impact values are finally obtained. Thirdly, horizontally comparative analysis is carried out to these three modes of the urban logistics distribution systems. Results show the advantages of the 3PL and the joint distribution modes in developing greener urban logistics distribution. Future research avenues and policy suggestions are proposed finally.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.6
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• pp.280-288
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• 2000

Recently, there has been growing interest in utilizing cogeneration(COGN) systems with a high-energy efficiency due to the increasing energy consumption and the lacking of energy resource. But an insertion of COGN system to existing power distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc, because of reverse power of COGN, especially in protective coordination. A study on a proper coordination with existing one is being required. The existing power distribution system is operated with radial type by one source and protection system is composed based on unidirectional power source. But an Insertion of COGN system to power distribution system change existing unidirectional power source system to bidirectional power source. Therefore, investigation to cover whole field of power distribution system must be accomplished such as changing of protection devices rating by increasing fault current, reevaluation of protective coordination. In this paper, simulation using PSCAD/EMTDC was accomplished to analyze effect of COGIN on distribution fault current. Also, the existing protection system of 22.9[kV] power distribution system and customers protection system to protect of COGIN was analyzed and the study on protective coordination between of two protection system accomplished.

• Journal of Distribution Science
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• v.21 no.5
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• pp.113-120
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• 2023

Purpose: The purpose of the study is to examine how payment systems for traditional distribution channels pursue changes and how they collaborate in-depth with fintech companies. This study examines the changing payment system through the strategic partnership between distribution companies and fintech companies. Research Design, Data and Methodology: The study conducted research using a variety of secondary materials and existing literature and also utilized the interview method. More specific and in-depth research is conducted through various literature studies and secondary data. Findings and Results: The findings of the study are as follows. First, distributors have occasionally directly adopted simple payment systems due to changes in payment systems as a result of online advances. Second, distributors were found to collaborate with fintech companies when not directly using simple payment. Conclusions: Such maneuvers by distributors are aimed at first, providing convenience and simplicity for consumers. Second, developing the ability to apply big data for accumulating consumer information and third, producing a customer lock-in effect by reducing the fees charged for existing payment services. The present study will provide many domestic and international distributors with a new perspective and practical implications in terms of the distribution and finance industries.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.21-27
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• 2011

Recently, new distributed power sources such as photovoltaic, wind power, fuel cell systems etc. are energetically interconnected and operated in the distribution feeders, as one of the national projects for alternative energy. When new power sources are considered to be interconnected to distribution systems, bi-directional power flow and interconnection conditions of new power sources may cause several power quality problems like voltage sag, voltage swell, harmonics, since new power sources can change typical characteristics of distribution systems. Under these situations, this paper deals with the analysis the power quality problems at primary and secondary feeders in distribution systems, when new power sources like photovoltaic (PV) systems are interconnected, by using the test devices for PV systems based on the LabVIEW S/W. This paper presents the test device which is consisted with model distribution system and model PV systems. By performing the simulation for power quality operation characteristic based on the test facilities, this paper presents the optimal countermeasures for power quality.