• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.911-919
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• 2013

This paper reports the development of test bed with the energy recovering technique using two-step boost converter. The device is utilized for LDC aging test of Hyundai Motor's LPI AVANTE HEV in mass production. The developed power recycle type test bed is designed as 1.5 kW class to test up to the maximum load power of LDC and is also designed to supply scant power supply up to 500 W after power recycle. The theoretical design analysis and operational characteristics analysis results of test bed are reported, and its practicality and reliability are verified through the test result. Also, the finally developed test bed confirms approximately 79~85 % energy saving effect compared to the usual traditional aging test system.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.835-842
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• 2020

This paper considers a method of reproducing abnormal and fault operation for smart monitoring of thrust bearing used in wave power generation system. In order to develop smart monitoring technology, abnormal and failure data of actual equipment are required. However, it is impossible to artificially break down the actual equipment in operation due to safety and cost. To tackle this problem, a test bed that can secure data through reproduction of a faulty operating environment should be developed. Therefore, in this study, test bed that can reproduce each situation was developed and the operation result was analysis after identifying the situation to be reproduced through the failure factor analysis of the thrust bearing.

• 한국정밀공학회지
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• 제23권6호
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• pp.111-118
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• 2006

Recently, the reliability evaluation and analysis are applied far many industrial products which are required to guarantee in quality and efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC (Automatic Tool Changer), which is a core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of reliability evaluation have shown the failure rates, MTBF (Mean Time Between Failure), reliability for those components of ATC and real tests reliability through the constructed reliability test-bed. It is expected that proposed methodologies would increase reliability for a high-speed line center.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1914-1917
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• 2005

Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC(Automatic Too Changer), which is core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), reliability for those components and real tests reliability through constructed reliability test-bed. It is expected that proposed methodologies will increase reliability for high speed line center.

• 한국염색가공학회지
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• 제34권4호
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• pp.241-249
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• 2022

As for military backpacks in Korea, utility backpack products equipped with various functions along with comfort and convenience are being developed. As a result, the volume and weight of the backpack increase, and many lightweight studies of the materials forming the backpack are being conducted. This study is a basic study on frame lightweight using fiber-reinforced composites to deal with aluminum, a back frame that maintains the shape of a backpack and provides stability when worn by combatants. As is known, only fiber-reinforced composites have sufficient light weight and mechanical properties, but the mechanical properties were reviewed by drilling holes to maximize the light weight. Tensile strength and flexural strength were measured by drilling 6mm, 12mm, 18mm, and 24mm holes, and the tensile strength and flexural strength were measured when 1, 3, 5, and 7 holes of 12mm were increased. As a result, even when the number of holes was increased, tensile strength did not change significantly, and the flexural strength showed to be higher in the case of 3 holes and 5 holes than in the case of 1 hole.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.169-176
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• 2014

As body postures on bed affects various sleep related diseases, it is considered as important information when monitoring sleeping in daily life. Though there have already been a few approaches to monitor body postures on bed conventionally, the development for simple and unconstrained methods is still needed to realize the long-term daily monitoring. Focusing on the fact that ballistocardiogram changes depending on the body postures on bed, we developed a novel method to estimate body posturesusing extremely simple, film-type ballistocardiogram sensor which is based on polyvinylidene fluoride(PVDF) film. With 10 subjects, we performed two experiments. One was for an estimation test to show that body postures on bed can be estimated by ballistocardiogram, and the other was for a reproducibility test to present the feasibility of ballistocardiogram based body postures monitoring. To estimate body postures on bed, we made an individual template set of body postures by designating one ballistocardiogram (BCG) sample as a template in each postures. Then, we calculated Pearson's correlation coefficients between a sample and each templates and estimated the body posture of the sample by choosing a posture which corresponds to the most significant correlation coefficients. As a result, we estimated body postures on bed with 99.2% accuracy in average and found that the estimation using ballistocardiogram is reproducible.

• 접착 및 계면
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• 제22권3호
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• pp.85-90
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• 2021

섬유강화 복합재료를 이용하여 다양한 제품을 개발하고 있다. 제품화를 위해서는 기본적으로 복합재료의 인장강도 평가를 진행해야 한다. ASTM D3039 규격을 기반으로 섬유강화 복합재료가 평가되는데, 인장시편에 대한 변수 및 평가 조건에 따른 변수가 섬유강화 복합재료의 인장강도에 변화를 유발시킨다. 본 연구에서는 섬유강화 복합재료의 인장강도를 평가하는 ASTM D3039 기준을 따라 실험을 하되 탭, 시편의 두께, 탭을 붙이기 위한 접착제의 종류, 지그의 압력에 따른 섬유강화 복합재료의 인장강도 결과의 변화를 확인하였다. 시편의 두께에 따라 인장강도 및 인장탄성률의 변화가 있었다. 시편의 두께는 1-1.5 mm이 최적이며, 지그의 압력은 0.28 MPa, 탭을 붙이는 접착제는 접착력이 가장 우수한 구조용 접착제를 사용하는 것이 효과적이었다. 다양한 실험적 변수로 인해 오류를 일으킬 수 있었다. 접착제 및 탭, 지그 등에 대한 정확한 설정을 통해 효과적인 복합재료 평가가 이루어지길 희망한다.

• 한국군사과학기술학회지
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• 제20권2호
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• pp.181-186
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• 2017

Synthetic aperture radar(SAR) has been widely used for reconnaissance. It provides high-resolution, day-and-night and weather-independent images for a multitude of applications. Because SAR coherently combines many viewing angles to effectively create a large aperture(narrow beam) radar, the test-bed should be capable of moving straightly SAR sensor for the integration angle to meet resolution. This paper describes the test-bed developed to test and evaluate the SAR performance. It forms high-quality images in real time and saves the raw data for the purpose of post processing on the ground.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1851-1863
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• 2014

Many countries are increasing their investments in smart grid technology to enhance energy efficiency, address climate change, and trigger a green energy revolution. In addition to these goals, Korea also seeks to promote national competitiveness, prepare for the growth of the renewable energy industry, and export industrialization through its strategic promotion of the smart grid. Given its inherent representativeness for Korean implementation of the smart grid and its growth potential, Jeju Island was selected by the Korean government as the site for smart grid testing in June 2009. This paper presents a new design for the electricity market and an operational scheme for testing Smart Electricity Services in the Jeju smart grid demonstration project. The Jeju smart grid test-bed electricity market is constructed on the basis of day-ahead and real-time markets to provide two-way electricity transaction environments. The experience of the test-bed market operation shows that the competitive electricity market can facilitate the smart grid deployment in Korea by allowing various demand side resources to be active market players.

• International journal of advanced smart convergence
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• 제12권1호
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• pp.208-219
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• 2023

Recently, as mega-urbanization progresses, urban logistics centered on large cities is growing rapidly, and logistics transportation is increasing due to the lack of logistics infrastructure and the operation of a delivery system using cargo trucks in the city center. being cited as a cause. In order to solve this problem, domestic researchers are conducting research on the development of " Urban Underground railway Logistics System" that minimizes the initial infrastructure construction cost by utilizing the existing urban railway facilities in the city. Therefore, this paper analyzed the usage environment of the actual urban railway station to which the system will be applied in order to derive candidates for the test bed selection of "Urban Underground railway Logistics System". The evaluation criteria for test bed candidate role selection were established, and the candidate group derived from the Brown & Gibson model was used to evaluate the candidate group and derive the candidate role. A review of the results was conducted to contribute to the establishment of a test bed for the " Urban Underground railway Logistics System" under development.