• Journal of Korean Institute of Industrial Engineers
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• v.41 no.2
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• pp.209-219
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• 2015

This paper deals with a case study about productivity improvement in medium and small-sized manufacturing factories. It is popular to improve the productivity of lines by shortening the production cycles and assigning multi jobs to workers. We analyze the production lines and improve the productivity in the case study through multi-functional workers and shortened production lines. Based on the case study, we propose some guidelines to improve the productivity of production lines.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.154-161
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• 2014

To study and locate partial discharge(PD) and analyze the transient state of power transformer, there is a need for a high frequency model of transformer winding and calculation of its parameters. Due to the high frequency nature of partial discharge phenomenon, there is a need for an accurate model for this frequency range. To attain this goal, a Multi-Conductor Transmission Line (MTL) model is used in this paper for modeling this transformer winding. In order that the MTL model can properly simulate the transformer behavior within a frequency range it is required that its parameters be accurately calculated. In this paper, all the basic parameters of this model are calculated by the use of Finite Element Method (FEM) for a 20kV winding of a distribution transformer. The comparison of the results obtained from this model with the obtained shape of the waves by the application of PD pulse to the winding in laboratory environment shows the validity and accuracy of this model.

• Plant Resources
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• v.4 no.1
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• pp.31-35
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• 2001

Major characteristics of new Waesungri maize inbred line has multi-tiller and ears: five to six tillers and seven to eight ears per plant and flowering date of Waesungri was delayed about 18 and 24 days compared to Mo17 U.S line and IK$_4$ Korean local lines, respectively. Number of ears, fresh and dry weight per plant were significantly different among all tested hybrids including Waesungri/Sinkihong hybrid under different planting times and densities. Especially, both fresh and dry weight of IK$_1$/FR140//Waesungri F$_1$hybrid were significantly higher at high planting density. In kernel weight per unit area, Wnesungri/Sinkihong hybrid was high at high density and IK$_1$/FR140//Waesungri hybrid was high at low planting density. As results of analysis of variance, flowering date was shown a significantly different both planting times and varieties, while other characters including stem height were shown very variable in interactions with enviromental factors.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.2
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• pp.69-80
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• 2002

Sequential process of roll-bending and line heating has been used to deform the curved hull-plates in shipyards. A growing interest for the mechanization or automation of the line heating process has been noted. Relations between heating conditions and residual deformations are important components needed for the mechanization. The residual deformations are investigated by using a thermal elastic-plastic analysis based on the finite element analysis(FEA). Several experiments are also performed to examine the validity of the results of FEA. The input parameters of line heating are suggested by dimensional analysis of line heating. The dimensional analysis can extract the primary input-parameters of line heating. The relations between the heating conditions and the residual deformations are set up by multi-variate analysis and multiple-regression method. This study suggests a method for the relation between the heating conditions and the deformations lying under the line heating.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.525-533
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• 2023

Due to the topographical characteristics of Busan, which has many mountainous areas, there is a shortage of available land, and even the Gyeongbu Line railroad crosses the city center, hindering the disconnection of living areas and urban development. Accordingly, the need for multi-dimensional development has been raised to secure land, and recently, interest has been increasing in connecting cities divided by the undergroundization of the Gyeongbu Line railway and making efficient use of land. In this study, the development type was analyzed through the case of multi-dimensional development of land, and the development direction for each three-dimensional development type was set based on the results of the multi-dimensional development of four areas (Sasang Station, Gupo Station, Gaya Station, and Busanjin Station). In addition, reflecting the regional characteristics of the target area and the ongoing urban regeneration project, we will propose a design plan for horizontal and vertical space utilization of the railway site through multi-dimensional development through the efficient land use.

• Journal of Power Electronics
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• v.10 no.1
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• pp.85-90
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• 2010

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.277-281
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• 2005

Air-line mask is an important personal protective equipment for workers working under hazardous surroundings in which a fixed ventilation system is difficult to be installed. If the air-line mask make loud noise, works wearing the mask may be faced with health problems such as noise induced hearing loss(NIHL). The purpose of this study is to introduce a low noisy technology for workers using air-line mask. A traditional type air-line has been improved to an advanced air-line mask with lesser noise. In the mask, air suppling conduits consists of multi tubes are placed inside of the front of the safety helmet. The noise level reduced from 80dB(A) to less than 80dB(A) when measured by KS A 0701 method at Center for Safety Inspection, Testing and Certification for KOSHA. It is suitable for related regulation[Article 35 of the Industrial Safety and Health Act(Test of Personal Protective Equipment)]. While workers working in noise level of over 90dB(A), they may expose to 82dB(A) or less when they wear the advanced masks. This type masks can be an alternative for works suffering from loud noise generated by traditional air-line masks.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.86-92
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• 2021

As interest and demand for high value-added industries, including the global automobile and aerospace industries, have increased recently, demand for line centers with excellent performance that can respond to the production system for producing high value-added products is also rapidly increasing. A line center improves productivity based on the installed area using a multi-spindle compared to a conventional machining center. However, as the number of spindles increases, the weight increases and results in structural problems owing to the heat and vibration generated by each spindle. Therefore, it is necessary to improve machining precision through the structural improvement of the line center. This study presents research on the stabilization design of the line center through structural stability analysis through structural analysis to develop a compact multi-axis line center. An optimization model of the line center has been proposed to improve the processing precision and increase the rigidity by performing weight reduction based on the structural analysis results.

• ETRI Journal
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• v.29 no.4
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• pp.411-420
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• 2007

The steady evolution of mapping technology is leading to an increasing availability of multi-sensory geo-spatial datasets, such as data acquired by single-head frame cameras, multi-head frame cameras, line cameras, and light detection and ranging systems, at a reasonable cost. The complementary nature of the data collected by these systems makes their integration to obtain a complete description of the object space. However, such integration is only possible after accurate co-registration of the collected data to a common reference frame. The registration can be carried out reliably through a triangulation procedure which considers the characteristics of the involved data. This paper introduces algorithms for a multi-primitive and multi-sensory triangulation environment, which is geared towards taking advantage of the complementary characteristics of spatial data available from the above mentioned sensors. The triangulation procedure ensures the alignment of involved data to a common reference frame. The devised methodologies are tested and proven efficient through experiments using real multi-sensory data.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.131-137
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• 2004

In this paper, we proposed the method of the characteristic impedance and effective dielectric constant calculations of a parallel-two-wire transmission line coated with multi-layer dielectric material using conformal mapping method. First of all, we calculated the capacitance of the transmission line when coated by N layer dielectric material which has different thickness and dielectric constant and calculated the characteristic impedance and effective dielectric constant using calculated capacitances. When compared with the Maxwell 2D (made by Ansoft Corporation) simulation result calculated result was very similar to the simulation result within the four percent error range.