• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.903-906
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• 1997

When large capacity generation stations that consist of several large units tend to pull out of step from main power system, stabilizing control scheme as emergency control for preventing loss of synchronism of the whole stations with the remaining system is devided into two steps that the first step is to perform on-line prediction for out-of-step and the next step is on-line calculation of the amount of generation shedding for the rest of generators to be in step when out of step is expected. This paper presents on-line prediction scheme for out-of-step based on P-$\delta$ curve estimation using real-time measurement and on-line calculation of generation shedding. The proposed stabilizing scheme was applied to case study of real power system and the results obtained by the method compare well with the results by simulation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.2
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• pp.64-82
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• 1980

The aim of this thesis, when water permeates dam, is to study the shape of seepage line and seepage quantity. As for the process, various sand model dams of same capacity were constructed in the water tank : they are a central, middle, inclined, up and down stream point of which is paralled, and filter-installed types. And the slope of seepage line and seepage quantity in these various models for experiment were measured, observed data were analyzed, and several formulas which already published were compared and examined. As for the shape of seepage line, the relation between upstream water level and exit: slope of seepage line, near the entrance and exit point, geometrically similar model, and the shape of seepage line filter-installed were examined. As regards to the seepage quantity, several formulas which already published and testing result values were compared and examined, and relation with the slope of seepage line, the seepage quantity, the slope of upstream point, and the upstream water level were mutually studied. Particulary, when horizontal filter was installed, propriety of the existing formulas for effective filter length w as examined, and the relative position of exit point in various. conditions was also studied.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.297-306
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• 1995

An automatic transfer line consists of several stages(groups of stations) in series into one system by a common transfer mechanism and a common control system. In this system losses of the efficiency are evidenced in periods where a stage is forcod down- starved or blocked. The efficiency of an automatic transfer line can be improved by providing buffer storages between a stage or the length of line common senses there are several critical factors, system configurations relative position, and buffer capacity allocations in automatic transfer line are considered with a point of view production rates, average stock, and mean delay. The propose of this paper is to provide the robust designs by Taguchi method which improve the efficiency of four-stage transfer line.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.165-174
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• 2011

The purpose of this research is to develop the model for analyzing the hydraulic behavior of off-stream reservoir whose purpose is to reduce a peak flood. When a flood occurs in river, off-stream reservoir has a capability of sharing a part of peak flood. It is accomplished by flowing over a off-line weir that is built by lowering a portion of bank and connecting river with off-line reservoir. Since flood control depends on river elevation, characteristics of off-line weir (elevation, length, position et al.) and reservoir capacities, an integrated model linking the one dimensional unsteady river flow model, off-line weir model and two dimensional unsteady flood model is developed to analyze the behavior of off-stream reservoir and off-line weir. The results show that a flood control capability of off-stream reservoir strongly depends on facilities of off-line weir and storage capacity of offstream reservoir.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1405-1407
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• 2000

This paper is on optimal design for DC substation capacity for Mass Transit System. Three factors are considered for the design i.e. substation arrangements, line configuration and substation power capacity. In this study, we discussed substation power capacity only. At first, DC-fed-traction system is introduced on an outline, a characteristics of train and fed network. Optimal design procedures is described, and modelling for DC-fed-traction system are presented. The circuit-solution method is presented by matrix formula. In order to simulate DC substation power capacity more closely to actual situations, we proposed the program.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.398-401
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• 2000

This paper describes the design of optimal location and capacity of DC substation for Mass Transit System. Three factors are considered for the design i.e. substation arrangements, line configuration and substation power capacity. In this study, we considered all of them for capacity calculation of power supply system for MTS. At first, DC-fed-traction system is introduced on an outline, a characteristics of train and fed network, and design method of substation arrangements. Optimal design procedures are described, and program for capacity calculation of the system is presented. In addition, the computer simulated results are compared with the conventional simple calculation method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4918-4924
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• 2015

In this paper, we consider the capacity improvement of systems exploiting dual-polarized antennas for two-user transmission. To this end, we analyze the upper bounds of ergodic capacities for multicast and unicast data services in the systems, and propose the condition for adjusting the complex cross-polarization discriminations (XPDs) to maximize the ergodic capacities. In addition, we present the adjustment condition of the complex XPDs that can achieve spectral efficiencies close to the maximum ergodic capacities with lower system complexity. Lastly simulation results demonstrate that the systems using the proposed conditions can obtain higher spectral efficiencies than the ones employing different adjustment conditions including the exiting adjustment condition.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1579-1602
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• 2020

In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system's multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.

• Geotechnical Engineering
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• v.14 no.5
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• pp.67-76
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• 1998

The commonly used method to secure the stability of reinforced retaining structure is the reinfocement of backfill with connection attached or unattached to the geogrid type wall. Laboratory model tests for both cartes were conducted to investigate the effectiveness of geogridreinforcement, length of reinforcement inclusion, failure envelop, and the relationships between the face wall displacement and vertical settlement. The bearing capacity of each case was also determined. According to the model test results, geogrid-reinforced rigid wall is very effective for increasing the bearing capacity and reducing the displacement of retaining wall. The observed sliding line of model test is similar to the theoretical one.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1426-1428
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• 2000

A new block system - MAS (Moving Autoblock System) whose efficiency is higher than FAS(Fixed Autoblock System) in the loading capacity is required to accomodate the increasing transport volume. That MAS has higher efficiency has already been verified through various studies, especially in a line with different types of travelling trains. The efficiency of MAS for Korean high speed line with two different train model is analyzed by computer simulation. The results show that MAS is more efficient than FAS in the loading capacity.