• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.6
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• pp.505-510
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• 2013

An encircling send-receive type pulsed eddy current (PEC) probe is designed for use in aluminum tube inspection. When bare receive coils located away from the exciter were used, the peak time of the signal did not change although the distance from the exciter increased. This is because the magnetic flux from the exciter coil directly affects the receive coil signal. Therefore, in this work, both the exciter and the sensor coils were shielded in order to reduce the influence of direct flux from the exciter coil. Numerical simulation with the designed shielded encircling PEC probe showed the corresponding increase of the peak time as the sensor distance increased. Ferrite and carbon steel shields were compared and results of the ferrite shielding showed a slightly stronger peak value and a quicker peak time than those of the carbon steel shielding. Simulation results showed that the peak value increased as the defect size (such as depth and length) increased regardless of the sensor location. To decide a proper sensor location, the sensitivity of the peak value to defect size variation was investigated and found that the normalized peak value was more sensitive to defect size variation when the sensor was located closer to the exciter.

• The Journal of the Korean dental association
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• v.51 no.9
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• pp.501-510
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• 2013

This paper reviews a current view regarding the association between periodontitis and atherosclerotic cardiovascular diseases (ACVD). Many evidences have suggested that there exist biological mechanisms by which periodontitis can lead to ACVD. Periodontal infection can lead to direct bacterial invasion into endothelial tissues through the blood stream, then the bacteria can activate the host inflammatory response followed by atheroma formation, maturation and exacerbation. Also, chronic periodontal infections may indirectly induce endothelial activation or dysfunction through a state of systemic inflammation as evidenced by elevated plasma acute proteins, IL-6 and fibrinogen as well. There is moderate evidence that periodontal treatment can reduce systemic inflammation and improvement of both clinical surrogate markers. But there is no periodontal intervention study available on primary ACVD prevention. There is consistent and strong epidemiologic evidence, including in vitro, animal and clinical studies, that periodontitis imparts increased risk for future ACVD. However, evidences from intervention trials to date are not sufficient to confirm the multi directional causality of periodontitis in ACVD etiology. Well-designed intervention trials on the impact of periodontal treatment on the prevention of ACVD outcomes are needed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.504-510
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• 2002

Recently, thin film capacitors of high dielectric constant and low leakage current are applied to integrated devices. In this study, (Ba, Sr)$TiO_3$ (BST) thin films for low cost were prepared by Sol-Gel method. BST solution was spin-coated on Pt/$SiO_2$/Si substrate at 4,000 rpm for 10 seconds. Coating process was repeated 3 times and then sintered at $700^{\circ}C$ for 30 minutes. Structural and electrical characteristics of each specimen were analyzed by TG-DTA, SEM, fractal phenomenon, voltage-current and dielectric factor. Thickness of BST ceramics thin films are about 2,600~2,800 ${\AA}$ at depositing 3 times. Dielectric constant of thin films was decreased in 1 kHz~1 MHz. Dielectric constant and loss to frequency were 250 and 0.02 in $(Ba_{0.7}Sr_{0.3})TiO_3$ (BST3). Leakage current of BST3 was $10^{-9}\sim10^{-11}$/ A under 3 V.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.6
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• pp.510-517
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• 2003

An experimental study on the pressure drop during flow boiling for pure refrigerants R134a and Rl23, and their mixture was carried out in a uniformly heated horizontal tube. Tests were run at a pressure of 0.6 MPa and in the ranges of heat flux 5~50 kW/m$^2$, vapor quality 0~100 percent and mass velocity of 150~600 kg/m$^2$s. Generally, the two-phase frictional multiplier is used to predict the frictional pressure drop during the two-phase flow boiling. The obtained results have been compared to the existing various correlations for the two-phase multiplier. Also, the frictional pressure drop was compared to a few available correlations; The Lockhart-Martinelli correlation considerally overpredicted the frictional pressure drop data for mixture as well as pure components in the entire mass velocity ranges employed in the present study, while the Chisholm correlation underpredicted the present data. The Friedel correlation was found to satisfactorily correlate the frictional pressure drop data except for a low quality region.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.4
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• pp.191-196
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• 2005

This study was carried out to investigate the heat storage/release characteristics of the thermochemical reaction of the calcined dolomite with the packed bed shape experimental apparatus for development of chemical heat pump system. In the present study, it was found that MgO of the calcined dolomite was not hydrated during the hydration process under the experimental conditions. Therefore, the MgO of the calcined dolomite can be regard as an inert material. As a result, it was found that all of CaO packed kept the reaction temperature of about $510^{\circ}C$ through the entire part of the bed. The dehydration reaction was incurred first at the wall side area as the supplied heat was transferred through the wall side into the packed bed. As a result of the temperature and concentration spread, the reaction was completed at the wall side progressed into the center.

• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.491-510
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• 2017

This study analyzes on conjecturing tasks in elementary mathematics textbook. We adopted Peircean semiotic perspective and variation theory to analyze conjecturing tasks in elementary mathematics textbook. We specifically analyzed mathematical tasks designed to support students' inquiries into definitions and properties of quardrilaterals. As a result, we found that conjecturing tasks in textbooks do not focus on supporting students' diagrammatic reasoning and inductive verification on provisional abductions. These tasks were mainly designed to support students' conjecturing on commonalities of mathematical objects rather than differences between objects.

• Journal of the Korean Society for Library and Information Science
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• v.20
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• pp.331-403
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• 1991

1. The Purpose of the Research Historical study on the early woodblock printing in Korea has been mostly focussed on woodblock-printed books. Whereas, researches on those who pioneered to develop the advanced culture of the times have been very scant. Meanwhile, extant temple woodblock publications contain well preserved descriptions about Monk-Engravers and Sextons together with respective colophons at the end of the books. These records are very important research materials in the study of woodblock printing history and are also very useful source materials for discernment in conducting historical research about woodblock-printed books. Based on these records, this research has revelaed the characteristics of the Engrevers and realities of engraving activities, and by doing this, has clarified the characteristics of temple woodblock publications, and discussed the historical research about the woodblock-printed-publications by means of the Engravers. 2. Research Methods Temple woodblock publications with colophons in the nation's major libraries have been directly investigated and 3,059 Engravers were identified in 510 different woodblock-printed books, based on which this research and analysis have been conducted. 3. Research Results As a result of the research the followings have been clarified. A The Engravers' status composition and the motivation of engraving. B. The realities and tendencies of the Engravers' activities. C. The characteristics of the times found in the Engravers' lists. D. Historical research methods through the names of the Engravers.

• Fashion & Textile Research Journal
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• v.18 no.3
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• pp.282-288
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• 2016

This project aims to provide information on organizations and characteristics of Korean designer fashion industry in order to improve employment environment in fashion designer brands. This study utilizes the questionnaires and interviews with designers or human resources managers in Korean designer brands for forms, size and way of employment. The result shows that firstly, the size of employment in fashion designer brands is almost operated by small-scale human resources. Secondly, It is researched that they recruit less than 10 temporary employees per a brand on average as a problem. Thirdly, there are differences in business according to forms of employment. As researched, permanent employees usually conduct in design, products plan and production management, but, temporary employees conduct as a business assistant and salespeople. Fourthly, it is revealed that average salaries for permanents in fashion designer brands are between 1,510,000 and 2,000,000 won as the most people said. Moreover, the average salaries for temporaries are similar with permanents' as between 1,170,000 and 1,500,000 won. In fifth, in terms of the ways for recruitment, the proportion of job seekers who find a job by nonscheduled admission and special employment is larger than other ways. Finally, as a result of a research on an employment contract, employees have written the employment contract with the brands.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.503-510
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• 2016

In this paper I analyzed two decoding algorithms of decentralized LT codes for distributed storage by simulations in small-scale wireless sensor network. From the simulation results we can see that when the decoding ration is above 2.0, the successful decoding probability of OBP decoding is about 99%, while that of BP decoding is below 50% with n=100, and about 70% with n=200. We showed that OBP decoding algorithm is an efficient decoding scheme for decentralized LT codes for distributed storage in small-scale wireless sensor network.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.505-510
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• 1996

Many diseases cause other diseases with strength of influences and time intervals. Prognostic and therapeutic assessments are the important part of clinical medicine as well as diagnostic assessments. In cases where a patient already has manufestations of multiple disorders (complications), progress forecasting and therapy decision by physicians without support tools are very dificult: physicians often say that "Once complications set in, the patient may die". Treating complications are difficult tasks for physicians, because they have to consider all of the complexities, possibilities and interactions between the diseases. The prediction of multiple disorders has many bundles that arise from such time-dependent interrelationships between diseases and nonlinear progress. This paper proposes a model based on time-dependent influences, which appropriately describes the progress of mulitple disorders, and gives some modificaitons for applying this model to medical domains: time-dependent influence matrix manifestation vector, therapy efficacy matrix, S-shaped curve approximation, definitions of which are provided. This research proposes an algorithm for forecasting the state of each disease on the time horizon and for evaluation of therapy alternatives with not toy example, but real patient history of multiple disorders.disorders.