• Journal of Magnetics
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• v.17 no.2
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• pp.145-152
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• 2012

Patients who underwent hip arthroplasty using the conventional fat suppression technique (CHESS) and a new technique (IDEAL) were compared quantitatively to assess the effectiveness and usefulness of the IDEAL technique. In 20 patients who underwent hip arthroplasty from March 2009 to December 2010, fat suppression T2 and T1 weighted images were obtained on a 3.0T MR scanner using the CHESS and IDEAL techniques. The level of distortion in the area of interest, the level of the development of susceptibility artifacts, and homogeneous fat suppression were analyzed from the acquired images. Quantitative analysis revealed the IDEAL technique to produce a lower level of image distortion caused by the development of susceptibility artifacts due to metal on the acquired images compared to the CHESS technique. Qualitative analysis of the anterior area revealed the IDEAL technique to generate fewer susceptibility artifacts than the CHESS technique but with homogeneous fat suppression. In the middle area, the IDEAL technique generated fewer susceptibility artifacts than the CHESS technique but with homogeneous fat suppression. In the posterior area, the IDEAL technique generated fewer susceptibility artifacts than the CHESS technique. Fat suppression was not statistically different, and the two techniques achieved homogeneous fat suppression. In conclusion, the IDEAL technique generated fewer susceptibility artifacts caused by metals and less image distortion than the CHESS technique. In addition, homogeneous fat suppression was feasible. In conclusion, the IDEAL technique generates high quality images, and can provide good information for diagnosis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.893-898
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• 2003

This paper proposes a Truncated Type-II Hybrid ARQ scheme and coding techniques using an adaptive modulation system to achieve high throughput data transmission systems for wireless multimedia communication systems. In this paper, the adaptive modulation system analyzed in Nakagami (m-distribution) fading channel environment. The adaptive modulation system controls the modulation level and symbol rate according to the Nakagami fading parameter(m). When the received Eb/No is high or the Nakagami fading parameter m is high, the propose system selects higher modulation level and higher symbol rate to increase throughput. On the other hand, this system selects lower modulation level and lower symbol rate to prevent throughput performance degradation when the received Eb/No is low. The modulation method have been adopted QPSK(Quadrature Phase Shift Keying), 16QAM(Quadrature Amplitude Modulation), 64QAM, 256QAM. Therefore, adaptive modulation systems with truncated type-II hybrid ARQ scheme is proper for wireless multimedia communication system that require high reliability and delay-limited applications.

• Natural Product Sciences
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• v.20 no.4
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• pp.227-231
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• 2014

Cimicifuga heracleifolia extract (CHE) was investigated for its effects on the release of nitric oxide (NO) and at the level of inducible nitric oxide synthase (iNOS) gene expression in mouse macrophages. We found that C. heracleifolia elicited a dose-dependent increase in NO production and the level of iNOS mRNA. Since, iNOS transcription has been shown to be under the control of the transcription factor $NF-{\kappa}B$, the effects of CHE on $NF-{\kappa}B$ activation were examined. Transient expression assays with $NF-{\kappa}B$ binding sites linked to the luciferase gene revealed that the increased level of iNOS mRNA, induced by CHE, was mediated by the $NF-{\kappa}B$ transcription factor complex. By using DNA fragments containing the $NF-{\kappa}B$ binding sequence, CHE was shown to activate the protein/DNA binding of $NF-{\kappa}B$ to its cognate site, as measured by electrophoretic mobility shift assay. These results demonstrate that C. heracleifolia stimulates NO production and is able to up-regulate iNOS expression through $NF-{\kappa}B$ transactivation.

• Safety and Health at Work
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• v.8 no.2
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• pp.220-225
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• 2017

Background: Benzene is a known occupational and environmental pollutant. Its urinary metabolite trans, trans-muconic acid (tt-MA) has been introduced by some environmental and occupational health regulatory associations as a biological index for the assessment of benzene exposure; however, recently, doubts have been raised about the specificity of tt-MA for low-level benzene exposures. In the present study, we investigated the association between urinary levels of tt-MA and inhalational exposure to benzene in different exposure groups. Methods: Benzene exposure was assessed by personal air sampling. Collected benzene on charcoal tube was extracted by carbon disulfide and determined by a gas chromatograph (gas chromatography with a flame ionization detector). Urinary tt-MA was extracted by a strong anion-exchange column and determined with high-performance liquid chromatography-UV. Results: Urinary levels of tt-MA in intensive benzene exposure groups (chemical workers and police officers) were significantly higher than other groups (urban and rural residents), but its levels in the last two groups with significant different exposure levels (mean = 0.081 ppm and 0.019 ppm, respectively) showed no significant difference (mean = $388{\mu}g/g$ creatinine and $282{\mu}g/g$, respectively; p < 0.05). Before work shift, urine samples of workers and police officers showed a high amount of tt-MA and its levels in rural residents' samples were not zero. Conclusion: Our results suggest that tt-MA may not be a reliable biomarker for monitoring low-level (below 0.5 ppm) benzene exposures.

• Safety and Health at Work
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• v.5 no.2
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• pp.86-90
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• 2014

Background: Urinary 1-hydroxypyrene (1-OHP) was selected as a biomarker of polycyclic aromatic hydrocarbons (PAHs) to explore the accumulation level in the bodies of workers at rubber smoke sheet factories in southern Thailand. Methods: Spot urine samples were taken from four groups of workers from June 2006 to November 2007. The nonexposure or control groups included habitual cigarette smokers and nonsmokers. The other two groups were workers exposed to particle-bound PAHs from rubber wood smoke and they were nonsmokers. All spot urine samples were analyzed for 1-OHP and creatinine levels. Results: The mean${\pm}$standard deviation urinary 1-OHP in the control group of habitual smokers and the nonsmokers was $0.24{\pm}0.16{\mu}mol/mol$ creatinine and not-detected to $0.14{\mu}mol/mol$ creatinine, respectively. In the workers, the 1-OHP levels on workdays had no significant difference from the 1-OHP levels on the days off. The yearly average 1-OHP level was $0.76{\pm}0.41{\mu}mol/mol$ creatinine whereas the average 1-OHP level during 10 consecutive workdays was $1.06{\pm}0.29{\mu}mol/mol$ creatinine (p > 0.05). Conclusion: The urinary 1-OHP levels of workers exposed to PAHs were high. The accumulation of 1-OHP in the body was not clear although the workers had long working hours with few days off during their working experience. Therefore, a regular day off schedule and rotation shift work during high productive RSS should be set for RSS workers.

• Wind and Structures
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• v.27 no.5
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• pp.347-356
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• 2018

In this paper, stress distribution for a structurally stable greenhouse is considered in the present paper with subsequent investigation into the detailed stress distribution contour with the variation of self-weight and wind pressure level designation method under wind velocity of less than 30 m/sec. For reliable analysis, wind pressure coefficients of a single greenhouse unit were modeled and compared with experiment with correlation coefficient greater than 0.99. Wind load level was designated twofold: direct mapping of fluid dynamic analysis and conversion of modeled results into wind pressure coefficients ($C_P$). Finally, design criteria of EN1991-1-4 and NEN3859 were applied in terms of their wind pressure coefficients for comparison. $C_P$ of CFD result was low in the most of the modeled area but was high only in the first roof wind facing and the last lee facing areas. Besides, structural analysis results were similar in terms of stress distribution as per EN and direct mapping while NEN revealed higher level of stress for the last roof area. The maximum stress levels are arranged in decreasing order of mapping, EN, and NEN, generating 8% error observed between the EN and mapping results under 30 m/sec of wind velocity. On the other hand, effect of dead weight on the stress distribution was investigated via variation of high stress position with wind velocity, confirming shift of such position from the center to the forward head wind direction. The sensitivity of stress for wind velocity was less than 0.8% and negligible at wind velocity greater than 20 m/sec, thus eliminating self-weight effect.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.6
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• pp.1183-1192
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• 2022

Information and Information processing systems must maintain a certain level of security during the total life cycle of Information. To maintain a certain level of security, security management processes are applied to software, automobile development, and the U.S. federal government information system over a life cycle, but theme of no similar security management process in Korea. This paper proposes a Korean-style security risk management framework to maintain a certain level of security in the total life cycle of information and information processing system in the defense sector. By applied to the defense field, we intend to present the direction of defense security work in the future and induce an shift in security paradigm.

• Journal of Korean language education
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• v.28 no.3
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• pp.1-24
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• 2017

This article explores the developmental history of TOPIK over the last 20 years and its recent trends. Over the last two decades, TOPIK underwent two major systematic reforms, achieving both quantitative and qualitative growth over the course of its 52 testing sessions. TOPIK has utilized a six-level evaluation system from its inception to the present. The evaluation system was amended from the earlier six-test set - whereby each level corresponded with a separate test (1997~2005: the $1^{st}{\sim}9^{th}$) - to the three-test set (2006~2014: the $10^{th}{\sim}34^{th}$), and finally to the two-test set (2014~present: the $35^{th}{\sim}42^{nd}$). In the earlier exams, abilities in Vocabulary Grammar, Writing, Listening, and Reading were assessed. However, beginning with the $35^{th}$ TOPIK, abilities in Listening, Reading, and Writing (only in TOPIK II) were assessed and the evaluation of the writing section was changed to a task-based process, improving TOPIK into a more qualified analysis of proficiency. Over the last 20 years, the number of countries TOPIK is administered in has greatly increased from 4 to 73 countries, and the annual number of test-takers has also significantly increased from 2,692 to 250,141. The distribution of proficiency levels of the test-takers has shifted over time - initially "Beginner>Intermediate>Advanced" in the earlier exams, to "Intermediate>Advanced>Beginner" after the mid 2000s - as the number of those studying the Korean language for specific purposes and continuing education increased. Test-takers have indicated a shift in their purpose for taking the exam, initially citing "to assess proficiency" and more recently selecting "to study abroad," and this could also correlate with changes in the proportion of test-takers' proficiency level. In general, 85~95% of beginner, 50~65% of intermediate, and 45~60% of advanced test applicants passed the respective proficiency level. To date, no practices have yet been implemented to standardize the difficulty level longitudinally across test sets.

• Journal of Distribution Science
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• v.13 no.8
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• pp.73-80
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• 2015

Purpose - This study's objective is to analyze the content of the communications between users and producers based on the construal level theory. User generated content refers to content created in an online-based service where users and producers communicate interactively with each other. In a user generated content platform, the messages sent and received between the many players, the users and producers who use the content, may be analyzed at the psychological level based on construal level theory. Research design, data, and methodology - This study gathered user and producer participation through a snow-bowling sampling method. The data analyzed includes 125 video clips and 2,912 comments. The period of the data collection was from September 2014 to December 2014. The collected data was analyzed using a t-test and two-way ANOVA. Results - This study obtained the following research results. First, users who were a short social distance from producers responded to user participatory activities stated in concrete language rather than abstract language. In contrast, users who were at a longer social distance from producers tended to respond to the content requesting user participation through abstract language. Second, if users and producers were at a short social distance from each other, user preference increased more when a producer response to user participation was expressed concretely rather than when it was expressed abstractly. In contrast, if the users were at a longer social distance, users' preferences increased more when producer response was expressed abstractly rather than when it was expressed concretely. Conclusion - This study found that the effect of suitability, in which the social distance and the content were in congruence at the construal level, could be observed. Therefore, based on this, academic and practical implications were drawn. The three main insights of the study are as follows. First, firms can use psychological factors to analyze the message content of users in their distribution platforms. This study reveals managerial implications for marketing managers who want to take make use of this analysis of user and producer communications. This study indicates that the main factors include the concrete and abstract scores and social distance between users and producers. Second, we also provide the strategic guidelines to maximizing user preferences and other outcomes. The main dependent variable in this study is the user preference shift; the variable increases through the congruence effect; and the construal level is determined by the social distance between the users and producers and the type of producer response. The outcomes here from users can be utilized to develop several systemic strategies. One process to use the outcomes could be: (1) firms could measure the users and producers social distance; (2) calculate the concreteness or abstractness of the messages; and, (3) predict the user preference outcomes by the congruence between user and producer social distance and the abstractness or concreteness of the message content.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.135-140
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• 2011

By investigating photoluminescence (PL) spectra (20 K) of undoped and Be-doped p-type GaSb/GaAs epilayers, the origin has been analyzed by the change due to doping density. We have observed that the PL peak shifts to higher energy and the full-width half-maximum (FWHM) decreases with increasing the doping density below ${\sim}10^{17}cm^{-3}$, contrasted to shift to low energy and increasing FWHM above the density of ${\sim}10^{17}cm^{-3}$. From the variation of the integrated PL intensities of three peaks dissolved by Gaussian fit, it has been analyzed that, as the density increases, the $Be[Be_{Ga}]$ acceptor level (0.794 eV) reduces, whereas the intrinsic defect of $A[Ga_{Sb}]$ (0.778 eV) enhances together with a new $Be^*$ level (0.787 eV) locating between A and Be. We have discussed that it is due to coexistence of the Be acceptor level (${\Delta}E=16meV$) and the complex level (${\Delta}E=23meV$), $Be^*[Ga_{Sb}-Be_{Ga}]$combined by Be and A, in Be-doped p-GaSb, and that the level density of $Be[Be_{Ga}]$ may be reduced above ${\sim}10^{17}cm^{-3}$.