• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.12
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• pp.1113-1122
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• 2005

The experimental heat transfer coefficients have been measured for two-phase convective boiling in two circular microtubes with inner diameters of $430{\mu}m\;and\;792{\mu}m$. While the heat transfer was greatly affected by the heat flux in the low quality region, the mass flux played a role in the high quality region. The smaller microtube had greater heat transfer coefficients. When the heat flux is varied from $20kW/m^2\;to\;30kW/m^2\;at\;G=240kg/m^2s$, the difference between the average heat transfer coefficients of the test tube $A(D_i=430{\mu}m)$ and the test tube $B(D_i=792{\mu}m)$ changes from $32.5\%\;to\;52.1\%$. At $G=370kg/m2^s$, the difference between the average heat transfer coefficients changes from $47.0\%\;to\;53.8\%$. A new correlation for the evaporative heat transfer coefficients in microtubes was developed by considering the following factors; the laminar flow heat transfer coefficient of liquid-phase flow, the enhancement factor of the convective heat transfer, and the nucleate boiling correction factor. The correlation developed in this study predicts the experimental heat transfer coefficients within an absolute average deviation of $8.4\%$.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.279-289
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• 2008

This study has the primary purpose to understanding the present situation through research on the actual condition about human resource outsourcing in the stocks and KOSDAQ enterprises, and would give the basic and useful data to develop human resource outsourcing. Data were collected from 1,500 charge of human resource management in the stocks and KOSDAQ enterprises which introduced or will be introduced human resource outsourcing. Frequencies, cross-tabs and independent-samples t-test were used to understanding the actual condition. Research findings are summarized as follows. First, as the introduction area of human resource outsourcing following training and development on the list were personnel information system, recruitment and selection. Second, tasks that transfer outsourcing supply firms owing to human resource outsourcing were common and typical operation function than complex and specific planning function.

• Safety and Health at Work
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• v.6 no.4
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• pp.268-278
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• 2015

Background: This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. Methods: The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration ($m/s^2$)], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. Results: More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient ${\beta}=-0.052$, standard error SE = 0.023), manufacturer (${\beta}=1.093$, SE = 0.227), rock hardness (${\beta}=0.045$, SE = 0.018), uniaxial compressive strength (${\beta}=0.027$, SE = 0.009), and density (${\beta}=-1.135$, SE = 0.235). Conclusion: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.1
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• pp.83-97
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• 2000

This article refers to the processions and the improvement of the 7th revised curriculum development for the Fisheries and Merchant Marine High School, published at Dec. 30, 1997. The general point of the 7th revised curriculum development was to cultivate creative Korean who will lead the epoch of globalization and information and to perform the learner-centered curriculum. Moreover, it defines the nature of Business High School not as completive but as continuing education. Based on this view, the improvment of 7th revised curriculum has been searched in varous sides. The group of general researchers and cooperators consisted of 12 members who were of university professors, teachers, related business men and executives in the administration branches, and the total researchers of 7th revised curriculum development were 90 members. The basic orientation of the research for the revised curriculum development was as following : The improvement of basic ability, job-analysis ability, integrity of theory and practice, acquisition of the certificate of national qualification, interrelation and cooperative role division between school and industrial fields, extension of self-decision ability of school and local society, protection of learner-selection right and maintaining close relations with the business-educational organization under life-long education system. Thus on the whole, the research for educational goals and contents, instructions, learning theory and evaluation is being processed with a high activity, based on the above mentioned plan of 7th revised curriculum development. At the same time, the methods and the models are being investigated. At last, it is to be noted that, in such as the 7th revised curriculum development research in this case, the effort should not be spared to harmonize the basic technological knowledge of the specialists in the Fisheries and Merchant Marine field and the cultural, liberal arts of personality education.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.548-558
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• 2013

In this work, laser induced breakdown spectroscopy (LIBS) is used to investigate soil samples collected from different desert areas of Riyadh city in Saudi Arabia. Both qualitative analysis and plasma parameters are studied via the observed LIBS spectra. These experiments have been done using a Spectrolaser-7000 system with 50 mJ fundamental wavelength of Nd:YAG laser and detection delay time of 1 microsecond. Many spectral lines are highly resolved for many elements like Al, Fe, Mg, Si, Mn, Na, Ca and K. The electron temperatures Te and electron densities Ne, for the constituent of generated LIBS plasma, are determined for all the collected samples. It is found that both Te and Ne vary from one desert area to other. This variation is due to the change of the elemental concentration in different desert areas that affects the sample's matrices. Time dependent measurements have also been performed on the soil samples. While the signal-to-base ratio (SBR) reached its optimal value at 1 microsecond, the plasma parameters Ne and Te reach values of $4{\times}10^{17}cm^{-3}$ and 9235 K, respectively, at 2.5 microsecond. The later indicate that the plasma cooling processes are slow in comparison to the previously observed results for metallic samples. The observed results show also that in the future it is possible to enhance the exploitation of LIBS in the remote on-line environmental monitoring application, by following up only the values of Ne and Te for one element of the soil desert sample using an optical fiber probe.

• The Korean Journal of Pain
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• v.34 no.4
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• pp.405-416
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• 2021

Background: This study investigated the effect of intrathecal Sec-O-glucosylhamaudol (SOG) on the p38/c-Jun N-terminal kinase (JNK) signaling pathways, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-related inflammatory responses, and autophagy in a spinal nerve ligation (SNL)-induced neuropathic pain model. Methods: The continuous administration of intrathecal SOG via an osmotic pump was performed on male Sprague-Dawley rats (n = 50) with SNL-induced neuropathic pain. Rats were randomized into four groups after the 7th day following SNL and treated for 2 weeks as follows (each n = 10): Group S, sham-operated; Group D, 70% dimethylsulfoxide; Group SOG96, SOG at 96 ㎍/day; and Group SOG192, SOG at 192 ㎍/day. The paw withdrawal threshold (PWT) test was performed to assess neuropathic pain. Western blotting of the spinal cord (L5) was performed to measure changes in the expression of signaling pathway components, cytokines, and autophagy. Additional studies with naloxone challenge (n = 10) and cells were carried out to evaluate the potential mechanisms underlying the effects of SOG. Results: Continuous intrathecal SOG administration increased the PWT with p38/JNK mitogen-activated protein kinase (MAPK) pathway and NF-κB signaling pathway inhibition, which induced a reduction in proinflammatory cytokines with the concomitant downregulation of autophagy. Conclusions: SOG alleviates mechanical allodynia, and its mechanism is thought to be related to the regulation of p38/JNK MAPK and NF-κB signaling pathways, associated with autophagy during neuroinflammatory processes after SNL.

• Korean Journal of Environmental Agriculture
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• v.40 no.2
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• pp.92-98
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• 2021

BACKGROUND: Unintentional residual pesticide in soil derived from preceding crops and the transfer to succeeding crops was considered a critical barrier for positive list system (PLS). Thus, an uncertain risk is predicted for ethoprophos applied at cultivation of preceding crop (Korean cabbage) to succeeding crop (spinach). METHODS AND RESULTS: Ethoprophos was treated on soil following the recommended dose and 5 times dose according to the safe use guidelines for Korean cabbage after seeding. On the 4 days after harvesting of preceding crop, spinach was sowed. The initial residual amounts of ethoprophos on soil (7.081-19.493 mg/kg) were decreased to 3.832-7.218 mg/kg until the harvest of Korean cabbage, and then finally decreased to 0.011-0.079 mg/kg after spinach cultivation. The uptake rates of ethoprophos from soil by Korean cabbage were 0.01-0.03% and distributed to root (0.150-0.903 mg/kg) and shoot (0.021-0.151 mg/kg), respectively. The residual amounts of uptake and translocation from preceding crop cultivated soil to spinach edible part were found to be below LOQ. CONCLUSION: The plant back internal (PBI) for ethoprophos is not recommended during sequential cultivation of leafy vegetables, since the residual amounts of ethoprophos in spinach were less than MRL (0.02 mg/kg).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.262-275
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• 2021

The expansion of the online market is expected to change the purchasing environment. The purpose of this study is to examine the difference in the moderating effect of each characteristic on perceived quality and purchase intention according to the group according to product involvement and purchaser age. The first step is to identify the characteristics of online information sources and social media platforms through a literature review. Next, when perceived quality affects purchase intention, we verify the moderating effect according to the characteristics of online information sources and social media platforms. The moderating effect is verified at the stage by dividing it into a group according to product involvement and a group according to age. The following results were confirmed throughout the study: First, perceived quality significantly affects purchase intention. Second, in the relationship between perceived quality and purchase intention, the influence of the moderating effect is different depending on the high-involvement product and the low-involvement product. Third, it was confirmed that there was a difference in the moderating effect of online information sources and social media platforms in the relationship between perceived quality and purchase intention according to age. This study intends to increase consumers' purchase intentions by identifying specific age groups and product groups of involvement and establishing strategies suitable for the characteristics of online information sources and social media platforms.

• Journal of Korean Medical classics
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• v.34 no.2
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• pp.1-22
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• 2021

Objectives : A transition course of 'Introduction to Clinical Korean Medicine' was developed to meet the demands for better preparation for clinical application of Korean Medicine within the curriculum. A Korean Medical Classics curriculum reflecting such demands was newly designed. Methods : Based on the 'Introduction to Clinical Medicine(ICM)' course of the Medical School curriculum that follows the medical education guideline, the 'Introduction to Clinical Korean Medicine(ICKM)' course was designed and developed. The role of Korean Medical Classics was suggested in the process. Results : In the following course, Korean Medical diagnosis, diagnostics, patient intake methods reflecting the Korean Medical diagnostic system, clinical skills, basic skills, treatment planning, patient education, etc. are included. Faculty members of the basic sectors of the Korean Medical school will participate in this curriculum, of which a head will be appointed to overlook the curriculum. In the case of Korean Medical Classics, previous learning outcomes need to be reorganized based on clinical expression while clinical case studies need to be added to course material. A more active approach utilizing new pedagogic strategies and teaching methods should be taken. Conclusions : The Korean Medical Classics curriculum could effectively take on the introductory role to clinical Korean Medicine, successfully strengthening the connection between the basic and clinical Korean Medicine to improve learners' satisfaction.

• Journal of Convergence for Information Technology
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• v.11 no.5
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• pp.94-103
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• 2021

This study aims to propose technical trading rules for Bitcoin futures and empirically analyze investment performance. Investment strategies include standard trading rules such as VMA, TRB, FR, MACD, RSI, BB, using Bitcoin futures daily data from December 18, 2017 to March 31, 2021. The trend-following rules showed higher investment performance than the comparative strategy B&H. Compared to KOSPI200 index futures, Bitcoin futures investment performance was higher. In particular, the investment performance has increased significantly in Sortino Ratio, which reflects downside risk. This study can find academic significance in that it is the first attempt to systematically analyze the investment performance of standard technical trading rules of Bitcoin futures. In future research, it is necessary to improve investment performance through the use of deep learning models or machine learning models to predict the price of Bitcoin futures.