• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.35 no.6
• /
• pp.568-575
• /
• 2022

This paper is a study on frequency analysis and electronic noise reduction of energy storage system (ESS). We acquired 4 necessary data for about 2 minutes and 4 seconds using a sampling frequency of 10,000 Hz in ESS. Fast Fourier transform (FFT) was used for electronic noise analysis from the acquired data. As a result, it was confirmed that DC component, fundamental wave, second and higher harmonic component exist. For the attenuation of harmonics, low-pass filter (LPF) was applied. We confirmed that an attenuation of approximately 59.3% appears from the second harmonic. The presence of many harmonic components in the data of the ESS was expected to occur due to the insufficiency of optimization among the modules inside the ESS. Therefore, we propose that a national certification system for ESS should be introduced to settle down the issue properly.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.311-317
• /
• 2007

"Environmentally Sound and Sustainable Development (ESSD)" is a key word in recent years. The construction industry, have put a great influence on ergonomic and sustainable environment. Recently, "green building certifications", such as Indoor Air Quality (IAQ) and eco-friendly material regulation have been established. With this regard, new construction and aged-housing remodeling projects are required to meet these certification criteria. Multi-housing residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Aged-housing remodeling project is very unique in that building residents are selected prior to design phase. Therefore, the analysis of resident's need for building materials in aged-housing remodeling is relatively easy compared to new building construction. As such, it is very important to analyze their preferences for eco-friendly materials prior to project execution. The purpose of this study is to find the needs of residents and priority of their needs. Based on their needs and priority, this paper provides a new strategy in using environment-friendly materials and maximizing their satisfaction level when aged housing remodeling is constructed. In addition, this paper provide new criteria in selecting new developed environmental materials in remodeling projects for the purpose of improving the safety and health level in construction industry.

• Journal of Distribution Science
• /
• v.22 no.1
• /
• pp.115-125
• /
• 2024

Purpose: This study is to analyze the purchasing process and distribution management requirements for teaching materials that have important meaning in the practical field of preschool education. Research design, data and methodology: A structured questionnaire was used to survey 103 childcare staffs regarding the purchasing process and distribution managements. The collected data underwent Likert's 5-point scale analysis and keyword grouping. Additionally, ANOVA was conducted to examine the distribution management demands based on demographic characteristics. Results: The purchasing of teaching materials involved more offline channels than online, and the purchase decisions were predominantly made by principals rather than teachers. Although the purchasing process is similar to that of general businesses, there are difficulties in purchasing due to the disorganized distribution channels and limited accessibility to product information. Additionally, the management of inventory for teaching materials is challenging due to limited personnel and storage. Childcare staffs have requirements for classification systems, evaluation criteria, environments and policies related to teaching materials distribution. The need to introduce a teaching material evaluation and certification system to ensure quality was not high. Conclusions: Most of the respondents recognized that strict management and measures should be taken for the distribution of teaching materials. There were differences in the demand of teaching material distribution depending on the respondents' status, age, education, and experience.

• Journal of the Korean earth science society
• /
• v.35 no.7
• /
• pp.585-597
• /
• 2014

This study surveys how teachers can improve their understanding about the concept of declination only through reading the material presented as non-dipole magnetic model. This study also investigates a difference between the content of declination presented in "Earth Science II" textbook under the 2009 revised National Curriculum and that of the past one. Thirty teachers in Gyeonggi province and thirty three in the city of Seoul are surveyed; they are selected from the participants of required training that provides their first grade regular teaching certification. Findings of this study are as follows. First, the study finds that teacher participants possess several misconceptions about the declination. Their typical misconception show that a compass needle directly indicates the magnetic north pole. This type of misconception is not corrected only by a reading the material. Second, the study shows that the degree of teachers' understanding about the concept of declination improves through the reading the material of a non-dipole magnetic model. Third, the study reveals that the material of nod-dipole magnetic model is more effective with teachers than students. Finally, the study suggests that explanations including non-dipole magnetic model be revised in the current textbooks.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.821-827
• /
• 2014

An isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) method has been developed and applied to the determination of arsenobetaine (AsB, ${(CH_3)_3}^+AsCH_2COO^-$) from oyster candidate certified reference material (CRM). The exact matching isotope dilution approach was adopted for accurate determination of AsB using $^{13}C_2$-labeled AsB as an internal standard. Efficiencies of different AsB extraction methods were evaluated using a codfish reference material and a simple sonication method was selected as the method of choice for the certification of the oyster candidate CRM. The hydrophilic interaction liquid chromatography (HILIC) combined with electrospray ionization tandem mass spectrometry (ESI/MS/MS) in selected reaction monitoring (SRM) mode was optimized for adequate chromatographic retention and robust quantification of AsB from codfish and oyster samples. By analyzing 12 subsamples taken from each 12 bottles systematically selected from the whole oyster CRM batch, the certified value of AsB was determined as $6.60mg{\cdot}kg^{-1}{\pm}0.31mg{\cdot}kg^{-1}$ and it showed excellent between-bottle homogeneity of less than 0.42%, which is represented by relative standard deviation of 12 bottles from the CRM batch. The major source of uncertainty was the certified value of the AsB standard solution.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.4
• /
• pp.425-432
• /
• 2021

In this paper, We produced supporting for ginseng cultivation facilities as a material recycling product of CPW(Complex Plastic Wastes, CPW) from households. And we analyzed the characteristics of material recycling products according to the amount of r-LDPE(Recycled low density polyethylene, r-LDPE) used. As a result, as the amount of recycled LDPE used increa sed, the tensile strength a nd elonga tion of ma teria l recycled products using CPW increa sed, but a sh decrea sed. When the recycled r-LDPE usage is 5% or more, the physical properties of the material recycling product using CPW stably satisfy the quality standard (GRM 3093-2021) of supporting for ginseng cultivation facilities.

• Fire Science and Engineering
• /
• v.29 no.4
• /
• pp.1-6
• /
• 2015

It is necessary to obtain a fire resistance certification in order to use SFRM in Korea. The fire resistance tests for certifications are performed separately for beams and columns and the certifications are different. We could assume that the same SFRM has different thicknesses for beams and columns because the conditions of the fire resistance tests for them differ in the section factors etc. But most of the SFRMs in Korea have the same thicknesses for beams and columns. So the question arises as to there were the differences between the fire test results for beams and columns reside. The purpose of this study is to consider the separate evaluation of the fire resistance of members through a comparative analysis of the temperature data obtained from fire certification tests.

• Journal of Chest Surgery
• /
• v.38 no.1 s.246
• /
• pp.1-12
• /
• 2005

The primary responsibility of a perfusionist is to operate the heart-lung bypass machine during open heart surgery, which is vital for the successful operative outcome. However, despite the perfusionist's crucial role on the cardiac surgical team, no relevant studies have not yet been conducted in our country. In this regard, this study was performed about the current status of perfusionists in Korea with comparative analysis on the certification and education system of perfusionists in foreign countries. Material and Method: We analyzed the demographic data on the Korean perfusionists conducted in 1994 and 2003, with comparison of recent data on the perfusionists of the nineteen foreign countries. Result and Conclusion: Although all agree that professionalism and responsibility of the perfusionist are essential in conducting a cardiac procedure and bringing about successful outcome, the formally approved training and certification system for perfusionists have not yet been established in Korea. Adequate measures should be done as soon as possible in order to try to obtain the adequate recognition of the profession.

• Advances in aircraft and spacecraft science
• /
• v.1 no.2
• /
• pp.233-251
• /
• 2014

Each aircraft have to be certified for a specified level of impact energy, for assuring the capability of a safe flight and landing after the impact against a bird at cruise speed. The aim of this research work was to define a scientific and methodological approach to the study of the birdstrike phenomenon against several windshield geometries. A series of numerical simulations have been performed using the explicit finite element solver code LS-Dyna, in order to estimate the windshield-surround structure capability to absorb the bird impact energy, safely and efficiently, according to EASA Certification Specifications 25.631 (2011). The research considers the results obtained about a parametric numerical analysis of a simplified, but realistic, square flat windshield model, as reported in the last work (Grimaldi et al. 2013), where this model was subjected to the impact of a 1.8 kg bird model at 155 m/s to estimate the sensitivity of the target geometry, the impact angle, and the plate curvature on the impact response of the windshield structure. Then on the basis of these results in this paper the topic is focused about the development of a numerical simulation on a complete aircraft windshield-surround model with an innovative configuration. Both simulations have used a FE-SPH coupled approach for the fluid-structure interaction. The main achievement of this research has been the collection of analysis and results obtained on both simplified realistic and complete model analysis, addressed to approach with gained confidence the birdstrike problem. Guidelines for setting up a certification test, together with a design proposal for a test article are an important result of such simulations.

• Journal of Information Management
• /
• v.43 no.1
• /
• pp.135-158
• /
• 2012

Since the 1990s, discussions regarding green libraries started in the U.S.A, in the name of 'library and the environment', 'Green librarians', 'constructing of environmental sources', 'noise and library', 'building libraries as an environmental alternative' and etc. Currently, green libraries certified by an evaluation system are more than 50. This study proposes a direction to build a green library. The study analyzes national and international green libraries certified by the evaluation system. The cases are analyzed based on the six evaluation factors in the LEED certification system; Sustainable Site, Water Efficiency, Energy and Atmosphere, Material and Resources, Indoor Environmental Quality, Innovation and Design Process. Since the evaluation system focuses mainly on the architectural aspects, there was a need of expanding the concept of eco-friendly in this research. The newly expanded eco-friendly concept includes services, content, and supplies of libraries.