• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.236-246
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• 2004

Artificial carious lesions in various depths were observed with visual examination using light transillumination, bite-wing radiography, laser fluorescence, and dye-enhanced laser fluorescence to determine the reproducibility, correlation of each diagnostic method, diagnostic sensitivity and diagnostic specificity. And optical densities according to demineralized times were measured whether laser fluorescence could be used as a quantitative diagnostic method. The following results were obtained whether laser fluorescence could be used for diagnosis of initial proximal caries. 1. Tau-c values of visual examination was 0.08 which showed lowest reproducibility and those of bite-wing radiography, laser fluorescence, dye-enhanced laser fluorescence were 0.60, 0.48, and 0.64, respectively which showed relatively high reproducibility. 2. The correlation between demineralization time and each examination was the highest in dye-enhanced laser fluorescence$({\gamma}=0.51)$ followed by laser fluorescence$({\gamma}=0.43)$, bite-wing radiograph$({\gamma}=0.35)$, and visual examination$({\gamma}=0.33)$. Dye-enhanced laser fluorescence and laser fluorescence showed significant correlation with demineralization time. 3. The sensitivity of laser fluorescence and dye-enhanced laser fluorescence for diagnosing approximal caries based on bite-wing radiography were 67%, 100% and those of specificity were 57%, 11% which showed diagnostic specificity was relatively lower than sensitivity. 4. The difference in optical density(DFR) between sound teeth and carious lesions according to lesion depth was high with dye-enhanced laser fluorescence compared with laser fluorescence. DFR measured with laser fluorescence according to changes in lesion depth was statistically significant but was not statistically significant with dye-enhanced laser fluorescence. Based on these results, laser fluorescence and dye-enhanced laser fluorescence have comparable diagnostic power as bite-wing radiography in early diagnosis of proximal caries.

• Journal of The Korean Association For Science Education
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• v.24 no.5
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• pp.902-915
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• 2004

Science drama can be an useful tool for understanding the nature of science, Science-Technology-Society relationship by providing indirect experiences to young students. Specific science concept and knowledge can also be learned with high interests. In this study, to explore the usefulness of science drama in elementary science lessons, two scripts of science drama and lesson plans were developed and implemented. Six step model for science drama lessons was also suggested. One was 'Manhattan Project' which dealt with social, ethical responsibility in using science & technology (science argument drama), and the other was 'Mom, My blood type is O' which explained the heredity of blood type (science concept drama). Two teachers were asked to write their journals during preparation and implementation of science drama lessons, and the lessons were observed by the researcher and video taped for analysis. Some students were interviewed just after the lessons by the teacher and all students were asked to write their impressions, change of their thought, what is leant etc. Overall responses of students and teachers on the two science drama lessons were very positive, 'Mom, My blood type is O' got more positive responses, and girls were more positive than boys. Some students anticipated another science drama even suggest topics for it. 'Mom, My blood type is O' was successful in making students (grade 3) understand the knowledge related with heredity of blood type (71% of the students got perfect answer). In 'Manhattan Project' students (grade 5) perceived more diverse location of responsibility after the lesson, but the danger and harmfulness of atomic power was embossed. This implied the need of more careful planning for the relevant learning activities before and after the play of science drama.Two teachers perceived the science drama as a new, useful tool for some subject which is hard to deal with by other teaching method. They were also satisfied with students' high interest and engagement during the science drama lessons but the extra time and effort for the lessons were pointed out as a main difficulties.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.261-284
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• 2018

The current international legal system does not provide a safeguard against the militarization and the weaponization of outer space. Although the term "peaceful use of outer space" in the 1967 Outer Space Treaty(OST) appears in official government statements or in multilateral space treaties, it is still without an authoritative definition in reviewing national practices. The ambiguous ban on weapons in Article IV of the OST allows countries to loophole on the deployment of other weapons other than nuclear weapons. Meanwhile "Draft Treaty on the Prevention of the Placement of Weapon in Outer Space and of the Threat or Use of Force against Outer Space Objects(PPWT)" to Conference on Disarmament (CD) commissioned by the UN General Assembly's Special Session jointly submitted by China and Russia in 2008 and later revised in 2014, attempting to define and prohibit the proliferation of weapons in outer space and provided definitions of prohibited weapons, are opposed by the US on the grounds that currently there is no arms race in outer space. Some experts support a hard law approach in which binding laws aimed at ultimately creating integrated and binding legal instruments in all aspects of the use of outer space should be adopted to regulate the military use of space. However as a temporary measure the soft law guidelines should be developed for the non liquiet, a situation where there is no applicable law. The soft law could be used to create support for the declaration of the treaties and to create international customary law. For example, the 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space that regulates the activities of the state in the exploration and use of the universe, and the 1992 Principles Relevant to the Use of Nuclear Power Sources in Outer Space will illustrated. While substantial portions of the former was codified later in the 1967 OST, the latter which, although written in somewhat mandatory terms, have been consistently complied with by states, have arguably become part of customary international law. On November 12, 1974, the General Assembly reaffirmed that the development of international law may be reflected inter alia, by declarations and resolutions of the General Assembly which may to that extent be taken into consideration by the International Court of Justice.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.415-425
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• 2001

Background : The correlation between the high resolution computed tomography(HRCT) emphysema score and the physiologic parameters including resting and exercise pulmonary function test was investigated in 14 patients($60.6{\pm}10.3$ years) with pulmonary emphysema. Methods : The patients underwent a HRCT, a resting pulmonary function test, and incremental exercise testing(cycle ergometer, 10 W/min). Computed tomography scans were obtained on a GE highlight at 10 mm intervals using 10 mm collimation, from the apex to the base after a full inspiration. The emphysema scores were determined by a CT program 'Density mask' outlining the areas with attenuation values less than -900 HU, indicating the emphysema areas, and providing an overall percentage of lung involvement by emphysema. Results : Among the resting PFT parameters, only the diffusing capacity(r=-0.75) and $PaO_2$ (r=-0.66) correlated with the emphysema score(p<0.05). Among the exercise test parameters, the emphysema score correlated significantly with the maximum power(r=-0.74), maximum oxygen consumption(r=-0.68), anaerobic threshold(V-slope method: r=-0.69), maximal $O_2$-pulse(r=-0.73), and the physiologic dead space ratio at the maximum workload(r=-0.80)(p<0.01). Conclusion: We could find that exercise testing parameters showed a much better correlation with the HRCT emphysema score, which is known to have a good correlation with the pathologic severity than the resting PIT parameters. Therefore it is suggested that exercise testing is superior to resting PIT for estimating in the estimation of the physiologic disturbance in emphysema patients.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.80-90
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• 2003

Background : Goblet cell hyperplasia is a critical pathological feature in hypersecretory diseases of the airways. A bacterial infection of the lung is also known to induce inflammatory responses, which can lead to the overproduction of mucus. Recently, mucin synthesis in the airways has been reported to be regulated by neutrophilic inflammation-induced epidermal growth factor receptor (EGFR) expression and activation. In addition, it was reported that migration of the activated neutrophils is dependent on the matrix metalloproteinases (MMPs), especially MMP-9. In this study, bacterial lipopolysaccharide (LPS)-induced goblet cell hyperplasia and mucus hypersecretion by EGFR cascade, resulting from the MMPs-dependent neutrophilic inflammation were investigated in the rat airways. Methods : Pathogen-free Sprague-Dawley rats were studied in vivo. Various concentrations of LPS were instilled into the trachea in $300{\mu}{\ell}$ PBS (LPS group). Sterile PBS ($300{\mu}{\ell}$) was instilled into the trachea of the control animals (control group). The airways were examined on different days after instilling LPS. For an examination of the relationship between the LPS-induced goblet cell hyperplasia and MMPs, the animals were pretreated 3 days prior to the LPS instillation and daily thereafter with the matrix metalloproteinase inhibitor (MMPI; 20 mg/Kg/day of CMT-3; Collagenex Pharmaceuticals, USA). The neutrophilic infiltration was quantified as a number in five high power fields (HPF). The alcian blue/periodic acid-Schiff (AB/PAS) stain were performed for the mucus glycoconjugates and the immunohistochemical stains were performed for MUC5AC, EGFR and MMP-9. Their expressions were quantified by an image analysis program and were expressed by the percentage of the total bronchial epithelial area. Results : The instillation of LPS induced AB/PAS and MUC5AC staining in the airway epithelium in a time- and dose-dependent manner. Treatment with the MMPI prevented the LPS-induced goblet cell hyperplasia significantly. The instillation of LPS into the trachea induced also EGFR expression in the airway epithelium. The control airway epithelium contained few leukocytes, but the intratracheal instillation of LPS resulted in a neutrophilic recruitment. A pretreatment with MMPI prevented neutrophilic recruitment, EGFR expression, and goblet cell hyperplasia in the LPS-instilled airway epithelium. Conclusion : Matrix metalloproteinase is involved in LPS-induced mucus hypersecretion, resulting from a neutrophilic inflammation and EGFR cascade. These results suggest a potential therapeutic role of MMPI in the treatment of mucus hypersecretion that were associated with a bacterial infection of the airways.

• KDI Journal of Economic Policy
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• v.34 no.2
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• pp.55-93
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• 2012

In Korea, energy policies are actualized through various energy-related plans. Recently, however, as high-ranking plans, which are very vision-oriented, continually set higher sector-by-sector goals, subordinate action plans, which require consistency, encounter distortions in their establishment process. Also, each subordinate action plan reveals limitations in terms of securing flexibility of the plan in responding to uncertainties of the future. These problems pose potential risks such as causing huge social costs. In this regard, with an aim to provide empirical evidence for discussions on improving the procedure for developing and executing Korea's energy plans, this study mainly analyzes the Basic Plan on Electricity Demand and Supply-one of the most important subordinate action plans-in order to explain the problems of the Basic Plan in a logical manner, and potential problems that could occur in the process of sustaining consistency between the Basic Plan and its higher-ranking plans. Further, this paper estimates the scale of social costs caused by those problems assuming realistic conditions. According to the result, in the case of where maximum electric power is estimated to be 7% (15%) less than the actual amount in the Basic Plan on Electricity Demand and Supply, the annual generation cost will rise by 286 billion won and (1.2 trillion won) in 2020. Such social costs are found to occur even when establishing and executing the Basic plan according to the target goal set by its higher-ranking plan, the National Energy Master Plan. In addition, when another higher-ranking GHG reduction master plan requires the electricity sector to reduce emissions by additional 5% in the GHG emissions from the right mix in electricity generation with 'zero' cost of carbon emission, the annual generation cost will rise by approximately 915 billion won in 2020. On the other hand, the analysis finds that since economic feasibility of electric powers in Korea varies significantly depending on their type, Korea is expected to face very small potential social costs caused by uncertainties over the future price of carbon dioxide in the process of establishing the Basic Plan.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.248-256
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• 2007

In this paper, we propose a selective DFT spreading method to solve a high PAPR problem in uplink OFDMA system. A selective characteristic is added to the DFT spreading, so the DFT spreading method is mixed with SLM method. However, to minimize increment of computational complexity, differently with common SLM method, our proposed method uses only one DFT spreading block. After DFT, several copy branches are generated by multiplying with each different matrix. This matrix is obtained by linear transforming the each phase rotation in front of DFT block. And it has very lower computational complexity than one DFT process. For simulation, we suppose that the 512 point IFFT is used, the number of effective sub-carrier is 300, the number of allowed sub-carrier to each user's is 1/4 and 1/3 and QPSK modulation is used. From the simulation result, when the number of copy branch is 4, our proposed method has more than about 5.2 dB PAPR reduction effect. It is about 1.8 dB better than common DFT spreading method and 0.95 dB better than common SLM which uses 32 copy branches. And also, when the number of copy branch is 2, it is better than SLM using 32 copy branches. From the comparison, the proposed method has 91.79 % lower complexity than SLM using 32 copy branches in similar PAPR reduction performance. So, we can find a very good performance of our proposed method. Also, we can expect the similar performance when all number of sub-carrier is allocated to one user like the OFDM.

• Korean journal of communication and information
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• v.57
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• pp.33-48
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• 2012

Over the last decades, the issue of work or labor has played a critical role in prevailing discourses to represent the changed economic reality. Aesthetic labor, cultural work, network labor, team-work and alike, have played a dazzling role to represent the emerging economic order, employing the word of labor. Certainly, it is not less than a part of a wide range of shifts in order to make capital work with more effect by making up a workable and governable subject. In this article, I try to examine shifts around the media work which has contributed to expand the new discourse of 'labor.' I will say that it is quite crucial for accounting for the reality of media work to shed light on moves to represent media work, and, among others, one to transform the subjectivity involved in it among others. Furthermore, it would be necessary to take a close look at the subjectivity of media work and its modification to deal with and eliminate the precariousness of media work. Saying about media work without paying any attention to heterogenous and various practices to compose a media work, one is forced to regard media work as the matter of economic and legal interests. In addition, it would bring about that the cultural political concerns of media work will be detached from critical sight of the media cultural studies. Referring to major studies around media work in critical media studies, cultural studies and political economy of communication, this article will briefly look into the arrangement of contentions around subjectivity of media work in South Korea. And it will try to suggest what cultural-political strategy we need to investigate, fighting against the hegemonic power to generate and regulate media work and its workers in precarious conditions. It does not intend to search the media work and its complicated realities in detail in South Korea. I wish that it would make a preliminary step to propose and elaborate the critical analysis of media work and its form of subjectivities.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.149-163
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• 2016

Seafarers are an essential resource in maritime industries, which provide navigation skills, vessel maneuvering skills and fishing skills in the fishery industry. They also work as a driving force in pilotage, port operation, vessel traffic service, and marine safety. Other areas in maritime services, which rely on seafarer include safety management of ships, supervisory activities, and maritime accident assessment. In these ways, Korean seafarers have contributed to the growth of Korean economy. However, there have been issues of high separation rate, shortage of supply, multi-nationality, multiplicity of culture caused by employment of foreign seafarers, and aging. The present paper finds that maritime officers and fishery officers demonstrate differences in the statistics of on-board job taking and separation: the separation rate of fishery officers is higher than that of maritime officers. The existing data and statistics by the Korea Seafarer's Welfare & Employment Center could be improved by changing its structure from time series to panel data. The Korea Seafarer's Welfare & Employment Center is the ideal institution for collecting the panel data, as it has already accumulated and published relevant statistics regarding seafarer. The basic design method of the panel data is to adopt and improve it by including the information on ratings of maritime and fishery industries, ranks in a ship, personal information, family life, and career goal. Panel data are useful in short- and long-term forecasts of supply of Korean seafarers; demand evaluation of education, training, and reeducation of the seafarers; demographical dynamic analysis on Korean seafarers; inducement policy of long-term on board job taking in harmony with man-power demands in marine industries such as pilotage service; implementation of job attractiveness policy on Korean seafarers; and employment stabilization of Korean seafarers.

• Food Science and Preservation
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• v.21 no.1
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• pp.129-139
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• 2014

This study was conducted in order to investigate the optimal fermentation periods of the Smilax china L. leaves as a fermented tea via Aspergillus oryzae for 0 (non-fermented), and 10, 20, and 30 days (NF, F10, F20, F30). It was also observed for its quality characteristics. In the color and spectrum (400~700nm) of 1% tea water extract, NF was light yellow, whereas fermented tea (F10~F30) was light red color, and the F10 among F10~F30 has the clearest color and spectrum. Furthermore, acceptabilities of aroma and brightness were insignificantly different between NF and F10~30, while the mouth feel and overall acceptabilities were insignificantly distinct among all of the fermented teas. Therefore, these results suggest that the appropriate fermentation period for tea fermentation is 10 days. On the other hand, the total polyphenol and flavonoid content in the NF was the highest among all of the fermented teas. In the antioxidant parameters, EDA (electron donating ability), FRAP (ferric reducing antioxidant power), and LPOIA (lipid peroxidation inhibitory activity) in the NF were the highest among all fermented teas. Meanwhile, the XOI (xanthine oxidase inhibitory activity) was low, as well as insignificantly different from NF and F10~F30, whereas the AOI (aldehyde oxidase inhibitory activity) was markedly higher (38.09~41.70%) by the hot water tea extract (with or without fermentation), particularly the AOI that has increased via fermentation. In conclusion, the overall antioxidant activity tended to be reduced by fermentation; however, the EDA, FRAP and LPOIA in the fermented tea for 10 days was higher than the activities during 20~30 days of fermentation. There was a similar result in the color and acceptability of fermented tea for 10 days, which was remarkably better than those of 20-30 days. Therefore, fermented tea from the leaves of Smilax china L. could be expected to be used as a functional tea without the loss of inhibitory activity of both the XO and AO via fermentation.