• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.369-372
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• 1996

The factory under this study consists of mixed-model assembly lines and workcenters which provide parts to the main lines. Parts produced by the workcenter have different specifications for different product models. The workcenters fabricate parts in batches, and they are divided into two types. A type 1 center supplies parts only to the main line that is designated to the center while type 2 center provides parts to all the main lines. The purpose of this study is to develop a scheduling scheme for the workcenter, and the main objective of the schedules is to provide parts for the main lines without delay. The facts that make the scheduling challengeable are that 1) the different models existing together on a main line request different parts, 2) the spaces for part inventories are limited and 3) set up times are sequence dependent and long in some cases. This study presents developed scheduling schemes for the type 1 center and explains the scheduling and control structure used.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.3
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• pp.339-345
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• 2016

This paper is concerned with the numerical simulation result of pressure propagation to the main charge by warhead penetration into concrete targets. In this study, we developed on-line pressure measurement method in the main charge during warhead penetration. Using the on-line pressure measurement method, we successfully recorded the pressure-time history in the main charge during the field penetration test. Then we compared result of numerical simulations with test data and found that the simulation results are in good agreement with the test results. Finally, through the numerical calculations it is concluded that the installation of liner is effective in reducing pressure level produced in the main charge.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.87-93
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• 2015

In this study, a numerical analysis was performed to simulate the thermal-hydraulic response of the secondary side of a steam generator(SG) model equipped with an orifice-type SG outlet flow restrictor to a main steam line break(MSLB) at a pressurized water reactor(PWR) plant. The SG analysis model includes the SG upper steam space and the part of the main steam pipe between the SG outlet and the broken pipe end. By comparing the numerical calculation results for the present SG model to those obtained for a simple SG model having no flow restrictor, the effects of the flow restrictor on the thermal-hydraulic response of SG to the MSLB were investigated.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.1
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• pp.14-21
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• 1979

This paper deals with tIne interface error in the on-line computer systems by using the FSK radio communications. The wideband frequency shrift keying method is used for briary data transmission between the remote terminals and the main computer. To mintmize the error rate In the decoder systems of the main computer, a synchronizing pulse is added to the frame, so that the phase In both receiver and transmitter are synchronized. When the information signal with a constant error bit is received through FSK, It is designed to use the microprocessor for calculation of error bit. As results, most bit error are caused in FSK radio communications. and a few error bit Is me - asured to enter the mirroprocessor from the input buffer.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1112-1114
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• 2017

The liquid rocket engine determines the routing of the component placement and layout by adapted the cycle method, the hardware configuration, the gimbal type on the functional implementation, and so on. In this paper, the conceptual routing of major pneumatic lines such as helium (He) supply pneumatic line for driving, many purge pneumatic line and main ignition line based on the main components installed in the liquid rocket engine was performed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.4
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• pp.159-163
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• 2013

In this paper, voltage quality improvement is analyzed in case of Superconducting Fault Current Limiter (SFCL) installed in grounding line of main transformer in power distribution system. First, a resistive-type SFCL model is used. Next, Korean power distribution system is modeled. Finally, when SFCL is installed in the starting point of feeder and grounding line of main transformer, voltage qualities are evaluated according to various fault locations and resistance values of SFCL using PSCAD/EMTDC. The voltage quality results in case of grounding line are compared with the voltage in case of feeder.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.73-79
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• 2011

This paper aims to find out the statistical characteristics of railroad weather-related accidents and incidents of each railroad line and then reduce the railroad accidents and prepare for the climate change. For this, we used data of KROIS and Korea railroad accidents report during 1996-2008. The results are as follows; Gyeongbu line is the most vulnerable line to railroad weather-related accidents, Yeongdong and Taebaek line are also the vulnerable line. The main railroad weather-related accidents and incidents is a railway obstruction and the next is a signal failure, a power supply failure. The second cause of a railway obstruction was some different for each line, but the main cause was a collapsed roadbed. We knew that the cold front accompanied with a heavy rainfall for a short time is the main weather pattern which cause the railroad accidents.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.77-87
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• 2015

Parallel lines are often used to increase production rate in many manufacturing systems where the main line splits into several lines in parallel, and after some operations, they merge into a main line again. Queueing networks with finite buffers have been widely used for modeling and analyzing manufacturing systems. This paper provides an approximation technique for multi-server two-stage networks with merge configuration and blocking which will be a building block for analysis of general manufacturing systems with parallel lines and merge configuration. The main idea of the method is to decompose the original system into subsystems that have two service stations with multiple servers, two buffers and external arrivals to the second stage are allowed. The subsystems are modeled by level dependent quasi-birth-and-death (LDQBD) process.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1-5
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• 2010

The Hyundai Rotem company is due to be conducted the main line Speed Qualification Test as regulated by CFR for SEPTA EMU and SCRRA Bi-level coach project. The regulated test items per 49CFR213.345 are wheel/rail interaction forces and carbody/truck accelerations during running on main line. Therefore the special two sets of instrumented wheelset (IWS) per each project have been made for measuring the interaction forces between wheel and rail at four wheels of one truck during running on main line. In this paper, regarding Speed Qualification Test, the required test items and data analysis method per 49CFR213.345 and the preparation status of instrumented wheelsets (IWS) are introduced.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1623-1630
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• 2018

Normally, various auxiliary loads are installed along with the main load in industrial applications. Usually, load transformers are used to convey such types of auxiliary loads. The transformers become energized when the loads are turned-on, consequently, high amplitude of inrush current appears at the output of the uninterrupted power supply (UPS) system. To mitigate these high current amplitudes, this manuscript suggests a three-phase line-interactive UPS system to counter the inrush current during the turning-on of the auxiliary load transformer while powering the main load by using a current controlled inverter. Experimental results of a laboratory-sized prototype are provided in the support of the proposed UPS system for validation.