• Journal of Venture Innovation
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• v.7 no.1
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• pp.167-182
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• 2024

The aim of this study is to empirically explore the operational spillover effect among companies within chaebol groups, prominent corporate conglomerates in South Korea. Chaebols are known for their horizontal and vertical integration, fostering close collaboration among their constituent companies from a supply chain standpoint. Existing literature highlights the sharing of tangible and intangible resources within chaebol structures, leading to increased efficiency by minimizing transaction costs through resource sharing. This research investigates whether operational management performance within chaebol structures can be transmitted through cooperative resource utilization. To achieve this objective, we categorize leading companies and affiliate companies within chaebols and examine whether the operational management performance of leading companies significantly influences that of affiliate companies. Data on conglomerates, as defined by the Korea Fair Trade Commission, were collected, along with information on companies within these groups. Subsequently, the company with the highest revenue within each group was identified as the leading company, while the remaining companies were designated as affiliate companies. Our analysis reveals a significant positive relationship between the performance of inventory and facility resource management of leading companies and that of affiliate companies. This study sheds light on the transfer of operational management performance within conglomerates from a managerial perspective, underscoring the importance of reinforcing cooperation systems within the chaebol group. Furthermore, this research contributes to the academic discourse by delineating conglomerates from an operational management perspective and empirically demonstrating the transfer effect of operational management performance.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.93-108
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• 2023

In manufacturing productivity analysis, understanding the intricate interplay among factors like facility performance, layout design, and workforce allocation within the production line is imperative. This paper introduces a simulation-based methodology tailored to food manufacturing, progressively expanding scenarios to analyze production enhancement. The target system is a food processing plant, encompassing production processes, including warehousing, processing, subdivision, packaging, inspection, loading, and storage. First, we analyze the target system and design a simulation model according to the actual layout arrangement of equipment and workers. Then, we validate the developed model reflecting the real data obtained from the target system, such as the workers' working time and the equipment's processing time. The proposed model aims to identify optimal factor values for productivity gains through incremental scenario comparisons. To this end, three stages of simulation experiments were conducted by extending the equipment and worker models of the subdivision and packaging processes. The simulation experiments have shown that productivity depends on the placement of skilled workers and the performance of the packaging machine. The proposed method in this study will offer combinations of factors for the specific production requirements and support optimal decision-making in the real-world field.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.259-266
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• 2020

This study analyzes the effects of the obsolescence assets on the asymmetry of costs. Cost asymmetry refers to a lower percentage of costs when sales fall than increases in costs when sales increase. the obsolescence asset induces various decisions, including high maintenance costs and management improvements and replacement of facilities. This study is to analyze the cost behavior according to those decisions. The analysis showed that the higher the obsolescence of assets rate, we found cost elasticity, with a greater reduction in costs when sales decrease than the increase in costs when sales increase. Second, the lower the cost will not appear as the obsolescence of assets rate increases in case that the concentration of an item of property, plant and equipment is high, and when sales decrease. The above result means that the obsolescence of assets rate acts as operating risk and thus operates resources flexibly according to changes in sales, but when the concentration of property, plant and equipment is high, the decision-making constraint make it difficult for the flexible operation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.141-148
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• 2008

This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.39-48
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• 2022

In earthquake situations, broadcasting and communication services are directly linked to rapid on-site rescue and effective restoration works. Recently, a variety of base isolation devices are widely introduced on building floors to avoid critical seismic damages of telecommunication facilities. However, in buildings with long fundamental periods, those devices may have undesirable amplification of seismic responses due to resonance effect between the building floors and base isolation devices. This study performs the seismic safety evaluation of two types of base isolation devices deployed for telecommunication facilities in mid- and high-rise buildings through numerical and experimental approaches. It is found that mid- and high-rise buildings can have low-frequency dynamic responses at the top floor when being subjected to design basis earthquake loading. Furthermore, bi-directional shake table testing demonstrated that the selected base isolation devices can exhibit unstable dynamic behaviors under such low-frequency excitations of the floor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.990-997
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• 2005

The stratified effect was investigated with three different types of diffuser shape in a thermal storage tank with variation of diffuser diameter, velocity, Froude number etc. Its effect was estimated by the degree of stratification. No matter of diffuser diameter and shape, the degree of stratification was the best as the Froude number gets closer to 1. In the case of a curved diffuser, when its diameter is a quarter of tank diameter and ejection velocity in a diffuser is approximately 0.2 m/s, the Froude number was almost 1. In the case of a flatted diffuser, when ejection velocity was 0.05 m/s, the Froude number was 1.5. Both cases which Froude number were nearer 1, showed the good degree of stratification.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.112.1-112.1
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• 2010

수소경제사회를 위한 수소인프라 구축에서 가장 중요한 부분이 현지설치형 수소스테이션이라고 하겠다. 이러한 수소스테이션은 일본, 미국, 유럽 등 선진각국에서 2015년에 상용화를 계획한 수소연료전지자동차의 보급에 필요불가결한 설비이므로 이들 지역을 중심으로 수요가 발생할 것으로 보인다. 선진국에서는 수소연료전지자동차의 경우 상용화가 이루어지면 2020년경 그 비율은 전체 자동차의 약 5% 수준을 점유할 것으로 보고 있다. 현재 국내에서도 정부주관으로 2015년부터 보급 목표로 수소연료전지차 모니터링연구가 수행되고 있다. 이에 따라 이미 외국 설비를 중심으로 수소스테이션 실증연구가 이루어졌으며, 각 기업체 및 연구기관에서 개질기, 고압압축기, 디스펜서 등 많은 요소기술 개발에 박차를 가하고 있으며, 이 결과로 향후 수소스테이션 국산화에 많은 기여를 할 것으로 사료된다. 아울러 이번 연구는 수소스테이션의 핵심부분인 수소스테이션용 제어로직을 개발하고 시뮬레이터를 제작한 결과에 대해 발표하고자 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.6
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• pp.556-565
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• 2004

We have experimented an actual solar water heating system acquiring real data for one year period. On the basis of the operation data, it is necessary to predict the system performance such as collector efficiency and solar fraction, and to analyze the economical efficiency for system optimal design. To estimate the performance of actual systems through simulation, valid modelling for components consisting of the system should be accompanied. The present study is focused on the modelling for load patterns and operating control conditions. We proposed two load models: concentration model which gathers real loads as a meaningful group and distribution model which disperses real loads with time. If grouping of the load distribution is suitable, the predicted values by the concentration model approaches to those by the distribution model close to actual load pattern apparently. As a result, both of them are in good agreement with those by experiment.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.995-996
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• 2011

전압의 시간적 변동으로 인하여 시각적 혹은 심리적으로 인식되는 불편함을 나타내는 플리커는 인간의 생체심리학적 인지능력과 관련이 있으며, 인간의 눈은 0.3%에서 0.4%의 매우 작은 전압변동에 대하여 5Hz에서 20Hz의 변조 주파수에서 민감하게 반응하며, IEC는 실증시험을 통해 8.8Hz의 전압변동에서 가장 민감하게 인식하는 것을 확인하였다. 이러한 플리커는 시각적 불쾌감과 함께 지속적인 경우 회전기와 같은 기기들에 악영향을 주며, 전자장비, 전구, CRT 장비, UPS 동기상실, 제어설비 및 보호설비의 오동작 발생으로 효과적으로 관리가 필요하다. 현재 국내 전기품질 관리기준은 IEC 국제규격을 바탕으로 제 개정 작업이 진행되고 있어 본 논문에서는 IEC 61000-3-7 국제규격을 국내 적용을 위해 필요한 국내 전력계통의 플리커 전달계수를 제시하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.97-100
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• 2004

This paper introduced an artificial fault generator which was operated in the Go-Chang field-test center and explained the result of single line-to-ground fault by AFG. The AFG can basically experiment line-to-line and line-to-ground faults. This facility directly connected distribution transmission lines, so the test results are very useful for power system analysis and protection. Using the function of the AFG, we briefly said the test methods ud results for the 22.9[kV-v] and $6.6[kV-{\Delta}]$ system.