• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.251-259
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• 2018

Metal hydride based hydrogen storage under moderate temperature and pressure gives the safety advantage over the gas and liquid storage methods. Still solid-state hydrogen storage including metal hydride is below the DOE target level for automotive applications, but it can be adapted to stationary or miliary application reasonably. In order to develop a modular solid state hydrogen storage system that can be applied to a distributed power supply system composed of renewable energy - water electrolysis - fuel cell, the heat transfer and hydrogen storage characteristics of the metal hydride necessary for the module system design were investigated using AB5 type metal hydride, LCN2 ($La_{0.9}Ce_{0.1}Ni_5$). The planetary high energy mill (PHEM) treatment of LCN2 confirmed the initial hydrogen storage activation and hydrogen storage capacity through surface modification of LCN2 material. Expanded natural graphite (ENG) addition to LCN2, and compression molding at 500 atm improved the thermal conductivity of the solid hydrogen storage material.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.117-124
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• 2017

In this study, we investigated the optimization of process conditions by using the Six Sigma process, design of experiment (DOE) method and response surface method (RSM) to resolve dimensional deviation and appearance problems arising from the shortened process time of the mobile phone rear cover. The analysis of the trivial many was performed by 2-sample T-test and cooling time, and mold temperature and packing pressure were selected as the vital fews affecting the overall width of the product. The optimal conditions of the process were then studied using the DOE and the RSM. We analyzed the improvement effects by applying the selected optimal conditions to the production process and the results showed that the difference between the mean value and target value of the overall width stood at 0.01 mm, an improvement of 88.89% compared to current process that fell within the range of standard dimension. The short-term process capability stood at $4.77{\sigma}$, which implied an excellent technology level despite a decrease by $0.22{\sigma}$ compared to the current process. The difference in process capability decreased by $2.44{\sigma}$ to $0.41{\sigma}$, showing a significant improvement in management capability. Ultimately, the process time of the product was shortened from 18.3 seconds in the current process to 13.65 seconds, resulting in a 34.07% improvement in production yield.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.51-59
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• 2015

The year 1997 was when Korean Journal of Public Relations Research started to publish research articles. This study addresses the issue of theories in Korean public relations research. A total of 166 research papers are analyzed to see characteristics and changes during 2003-2012. Through this meta analysis, the researcher tries to see the big picture and discusses the right direction for the future of the public relations in many ways. Three different groupings were adopted to classify theories in the 10 year perion - 1. origins of theories(public relations field, related neighbor field, distant field), 2. target of analysis(individual, organization, society), 3. level of approach (systematic pluralistic, rhetorical, critical approach). According to the findings, though getting better, it was 'cold season' in public relations research because theories utilized in Korean public relations research were not very excellent qualitatively and qualitatively. Interdisciplinary approach is discussed.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.238-246
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• 2020

Background: Dietary fat has been suggested to be the cause of various health issues. Obesity, hypertension, cardiovascular disease, diabetes, dyslipidemia, and kidney disease are known to be associated with a high-fat diet (HFD). Obesity and associated conditions, such as type 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD), are currently a worldwide health problem. Few prospective pharmaceutical therapies that directly target NAFLD are available at present. A Traditional Chinese Medicine, ginseng-plus-Bai-Hu-Tang (GBHT), is widely used by diabetic patients to control glucose level or thirst. However, whether it has therapeutic effects on fat-induced hepatic steatosis and metabolic syndrome remains unclear. Methods: This study was conducted to examine the therapeutic effect of GBHT on fat-induced obesity, hepatic steatosis, and insulin resistance in mice. Results: GBHT protected mice against HFD-induced body weight gain, hyperlipidemia, and hyperglycemia compared with mice that were not treated. GBHT inhibited the expansion of adipose tissue and adipocyte hypertrophy. No ectopic fat deposition was found in the livers of HFD mice treated with GBHT. In addition, glucose intolerance and insulin sensitivity in HFD mice was also improved by GBHT. Conclusion: GBHT prevents changes in lipid and carbohydrate metabolism in a HFD mouse model. Our findings provide evidence for the traditional use of GBHT as therapy for the management of metabolic syndrome.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.279-284
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• 2008

This paper aims to provide basic data for work environment control, prevention of worker exposure to asbestos and improvement of air quality to protect workers ‘health after measuring the level of airborne asbestos and workers' exposure in a shipbuilding repair businesses. For this study, a total of 27 samples were collected from 27 workers who had been exposed to asbestos during engine, piping, boiler and other manufacturing processes in 'A' Shipbuilding Repair Company in Gyeongnam. This research was conducted from Oct. 1 to 30, 2007 and had the following results: The target group (27 workers) consisted of all men with an average age of 35.9 years and 6.6 years of work on average. Among them, fifteen 15 (55.6%) were smokers. In terms of their duties at work, there were 12 plumbing repair engineers (44.4%), 8 boiler repair engineers (29.6%) and 7 engine engineers (25.9%). The geometric mean concentration of airborne asbestos was 0.004 f/cc. A total of 4 samples exceeded the exposure limit. In particular, three exceeded the legal limit by more than double, which means that some workers have been highly exposed to asbestos. In terms of the concentration of asbestos fibres by work process, plumbing repair was the highest (0.0071 f/cc($0.001{\sim}0.57\;f/cc$)) while boiler was the lowest (0.0015 f/cc($0.001{\sim}0.007\;f/cc$)). Based on this study, proper action needs to be taken as soon as possible to protect workers from the threat of asbestos.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.1-13
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• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• Journal of Climate Change Research
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• v.7 no.4
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• pp.373-381
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• 2016

Before the Conference of Parties (COP) 21 of the United Nations Framework Convention on Climate Change (UNFCCC) in 2015, most parties of UNFCCC had submitted their intended nationally determined contributions (INDCs) and to achieve their voluntary targets, some parties consider using international market mechanisms. As one of such mechanisms, Japan promoted its own bilateral mechanism called Joint Crediting Mechanism (JCM). In this study, feasibility studies and projects under JCM have been analyzed by project type, sector, country and region, which could provide some implications in designing Korea's future climate policy to achieve Korea's targets of 11.7% using international market mechanism in INDC. Since 2010, JCM has promoted 542 projects and feasibility studies in 44 countries according to the Institute for Global Environmental Strategies (IGES) database. Among 542 projects, about 80% were feasibility studies implying that JCM was more focused on project identification. However, current trends of JCM show that more projects will be soon implemented based on these feasibility studies. For sectoral categorization, projects were categorized into seven sectors-energy technology, energy efficiency, renewable energy, waste management, city, strategic planning and projects related to the country's efforts to reduce emissions from deforestation and forest degradation (REDD+). JCM projects were mitigation focused with more than 70% of projects were related to energy efficiency, renewable energy and energy technology. At the regional and country level, JCM is highly focused on Asia and especially, more than 100 projects were developed in Indonesia. Based on the analysis of JCM, in order to develop bilateral international mechanism for Korea, it is worthwhile to emphasize that Korea considers Asian countries as her partner. In addition, Korea may consider the collaboration with Multilateral Development Banks (MDBs) to implement projects identified by Korea and Asian partner countries. Furthermore, strategically, it is recommendable to develop jointly with Japan who has already capacity and networks with other Asian countries to mitigate GHG emissions. Such financial resources from MDBs and Japan may contribute to meet the 11.3% of GHG reduction target from abroad according to INDC of Korea.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.211-217
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• 2019

This study suggested the alternatives for improving consumers' engagement with digital signage (DS) by analyzing the researches of the effectiveness of DS in marketing and public areas, which is recognized as an essential communication tool for commercial or public matters. According to the results, affective DS ad content of DS resulted in positive shoppers' buying behaviors and perceiving buying environment; DS was also effective for public affairs, which how proper channel and message for the target public resulted in solving community problems. However, it was rare to measure precisely the level of consumers' engagement with DS content and what DS content aroused higher engagement in both areas. Thus, DS content should be more customized based on multiple converged contents for consumers' engagement and the research efforts of DS should be focused on the development of not only its device technology, but also creative content.

• Journal of Climate Change Research
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• v.9 no.1
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• pp.81-90
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• 2018

"The Framework Act on Low-Carbon Green Growth" specifies the requirements for the development and verification of emission factors for establishing reliable national greenhouse gas statistics. The scope of the regulations covers the development and validation of energy, industrial processes, solvents and other product use, agriculture, land use, land use change and emission and absorption coefficients of the forestry and waste sector as defined in the 1996 IPCC Guideline and GPG 2000, The minerals sector to be covered in this study belongs to industrial processes. As a representative method for quantifying and evaluating GHG emission factors, there are emission grade quality grading and DARS (Data Rating Rating System) in the 'Procedures for Preparing Emission Factor Documents (1997)' reported by US-EPA. However, the above two methods are not specific and comprehensive, and lack the details for accurate emission factor verification. Therefore, there is a need for a method for verifying and quantifying certified greenhouse gas emission factors that reflects characteristics of each industry sector in Korea and accord with IPCC G/L and GHG target management. In this study, we conducted a weighted study on quantitative and evaluation lists of emission factor using questionnaires to develop a more accurate methodology for quantifying national greenhouse gas emission factors in the mineral sector. Quantification and evaluation of emission factor are classified into essential verification and quality evaluation. The essential verifications are : administrative compatibility, method of determining emission factors, emission characteristics, sampling methods and analysis methods, representativeness of data. The quality evaluations consisted of the quality control of the data, the accuracy of the measurement and analysis, the level of uncertainty, not directly affect the emission factor, but consisted of factors that determine data quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.487-494
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• 2019

A Small-Sat Power System Design and Development should be depend on space environment such as solar wind with Electromagnetic field by hurdle of techniques. It is surmount solution of trend that will unitize and converge with power module in these days. The level of modularize means that applying Universal Middleware for payload power module requirements. The scope of target system is a main power provider module and operational subunit that can be implemented with the final power module distribution loads to consume for continuous process. A Universal Middleware strengthen to build power module from satellite power system should be accuracy and consuming data. A Power Service Module and dynamic system drive interactive management between power distribution and consumer module by Range Control. Consequently, suggesting evaluation, unexpecting payload system power consumer that makes fine variable resources in the development design process and efficiency.