• Food Engineering Progress
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• v.21 no.1
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• pp.57-63
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• 2017

This study investigated the effects of 27.12 MHz radio frequency (RF) heating on heat transfer phenomena during the thawing process of frozen food. To determine the velocity of the RF thawing machine, samples were frozen at $-80^{\circ}C$ and subjected to different power treatments. The phase change times (-5 to $0^{\circ}C$) of frozen radish were 30, 26, 13, and 8 min; those of pork sirloin were 38, 25, 11, and 5 min; those of rump were 23, 17, 11, and 6 min; those of chicken breast were 42, 29, 13, and 9 min; and those of tuna were 25, 23, 10, and 5 min at 50, 100, 200, and 400 W, respectively. The heating limit temperatures of the radish, pork sirloin, rump, chicken breast, and tuna samples were 19.5, 9.2, 21.8, 8.8, and $16.8^{\circ}C$ at 50 W; 23.5, 15.5, 27.3, 12.3, and $19^{\circ}C$ at 100 W; 42, 26.9, 45.7, 22.1, and $39.4^{\circ}C$ at 200 W; and 48.5, 54.7, 63.6, 57.3, and $44.9^{\circ}C$ at 400 W. These results suggest that high-power RF improves thawing velocity and heating limit temperatures, and that an improvement on the operation of the RF thawing machine, according to food temperatures, is needed.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1503-1517
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• 2018

Mt. Baekdu is a stratovolcano located at the border between China and North Korea and is known to have formed through its differentiation stage after the Oligocene epoch in the Cenozoic era. There has been a growing interest in the magma re-activity of Mt. Baekdu volcano since 2010. Several research projects have been conducted by government such as Korea Meteorological Administration and Korea Institute of Geoscience and Mineral Resources. Because, however, the Mt. Baekdu volcano is located far from South Korea, it is quite difficult to collect in-situ observations by terrestrial equipment. Remote sensing is a science to analyze and interpret information without direct physical contact with a target object. Various types of platform such as automobile, unmanned aerial vehicle, aircraft and satellite can be used for carrying a payload. In the past several decades, numerous volcanic studies have been conducted by remotely sensed observations using wide spectrum of wavelength channels in electromagnetic waves. In particular, radar remote sensing has been widely used for volcano monitoring in that microwave channel can gather surface's information without less limitation like day and night or weather condition. Radar interferometric technique which utilized phase information of radar signal enables to estimate surface displacement such as volcano, earthquake, ground subsidence or glacial movement, etc. In 2018, long-term research project for collaborative observation for Mt. Baekdu volcano between Korea and China were selected by Korea government. A volcanic specialized research center has been established by the selected project. The purpose of this paper is to introduce about remote sensing techniques for volcano monitoring and to review selected studies with remote sensing techniques to monitor Mt. Baekdu volcano. The acquisition status of the archived observations of six synthetic aperture radar satellites which are in orbit now was investigated for application of radar interferometry to monitor Mt. Baekdu volcano. We will conduct a time-series analysis using collected synthetic aperture radar images.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1041-1053
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• 2018

In this study, a real-time storage level and capacity monitoring and forecasting system for Yongdam Dam watershed was developed using high resolution satellite image. The drought indices such as Standardized Precipitation Index (SPI) from satellite data were used for storage level monitoring in case of drought. Moreover, to predict storage volume we used a statistical method based on Principle Component Analysis (PCA) of Singular Spectrum Analysis (SSA). According to this study, correlation coefficient between storage level and SPI (3) was highly calculated with CC=0.78, and the monitoring and predictability of storage level was diagnosed using the drought index calculated from satellite data. As a result of analysis of principal component analysis by SSA, correlation between SPI (3) and each Reconstructed Components (RCs) data were highly correlated with CC=0.87 to 0.99. And also, the correlations of RC data with Normalized Water Surface Level (N-W.S.L.) were confirmed that has highly correlated with CC=0.83 to 0.97. In terms of high resolution satellite image we developed a water detection algorithm by applying an exponential method to monitor the change of storage level by using Multi-Spectral Instrument (MSI) sensor of Sentinel-2 satellite. The materials of satellite image for water surface area detection in Yongdam dam watershed was considered from 2016 to 2018, respectively. Based on this, we proposed the possibility of real-time drought monitoring system using high resolution water surface area detection by Sentinel-2 satellite image. The results of this study can be applied to estimate of the reservoir volume calculated from various satellite observations, which can be used for monitoring and estimating hydrological droughts in an unmeasured area.

• Journal of Korean Philosophical Society
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• v.126
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• pp.263-293
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• 2013

Die vorliegende Abhandlung beachtet die methodologische $N{\ddot{u}}tzlichkeit$ der Dialektik $f{\ddot{u}}r$ die philosophische $Wissenschaftst{\ddot{a}}tigkeit$ des Aristoteles in einer besonderen Aufmerksamkeit auf den Begriff "${\delta}{\iota}{\alpha}{\pi}o{\rho}{\varepsilon}{\iota}{\nu}$". Bei Aristoteles bedeutet "${\delta}{\iota}{\alpha}{\pi}o{\rho}{\varepsilon}{\iota}{\nu}$" 'das durchaus $gr{\ddot{u}}ndliche$ Untersuchen einer Aporie', und eine solche Untersuchungsweise folgt der Dialektik. Deshalb beabsichtige ich zuerst, durch eine Begriffsanalyse und - interpretation von "${\delta}{\iota}{\alpha}{\pi}o{\rho}{\varepsilon}{\iota}{\nu}$" die dialektische Aporetik zu bestimmen als eine Argumentationsmethode nicht nur in einer dialogischen, sondern auch in einer nicht-dialogischen Situation. Besonders will ich einen methodologischen Grund $daf{\ddot{u}}r$ suchen, dass ein allein Forschender in der nicht-dialogischen Situation die dialektische Aporetik verwendet, indem ich einen Text von "De caelo" II 13, 294b 6~13 interpretiere. $N{\ddot{a}}mlich$ betont Aristoteles in Bezug auf den Durchgang der $Wissenschaftst{\ddot{a}}tigkeit$ eine Forderung der selbstkritischen Haltung, die der allein Forschende sich selbst seine Untersuchung in $R{\ddot{u}}cksicht$ auf die anderen Untersuchungen und auch auf die vorhersehbaren Hypothesen ${\ddot{u}}berpr{\ddot{u}}fen$ und verifizieren, um die aus seiner Untersuchung zu entdeckenden Aporien auf die dialektische Weise zu $l{\ddot{o}}sen$. Und diese Position von Aristoteles kann der wichtige Grund $daf{\ddot{u}}r$ sein, den fachsprachlichen Sinn von "${\delta}{\iota}{\alpha}{\pi}o{\rho}{\varepsilon}{\iota}{\nu}$" als auch den wissenschaftlichen Sinn der dialektischen Untersuchung der Aporie richtig verstehen und $erkl{\ddot{a}}ren$ zu $k{\ddot{o}}nnen$. Zuletzt bin ich in der Absicht, die dialektische Aporetik und ihre Funktion in drei Modeln zu formulieren und einige Beispiele $f{\ddot{u}}r$ jedes Model vorzustellen, um zu zeigen, auf welche Art und Weise Aristoteles die dialektische Aporetik $f{\ddot{u}}r$ den Lauf seiner Theoriebildung in der Tat anwendet. Durch solchen Versuch $w{\ddot{u}}nsche$ ich, dass meine Untersuchung ${\ddot{u}}ber$ die dialektische Aporetik etwas besseres $Verst{\ddot{a}}ndnis$ $f{\ddot{u}}r$ die wissenschaftliche Bedeutung der aristotelischen Dialektik anbieten $k{\ddot{o}}nnte$, und auch dass diese Studie als bedeutsame Basisdaten zu einer noch tieferen Forschung und $Verst{\ddot{a}}ndigung$ ${\ddot{u}}ber$ die philosophische Haltung und Methode des Aristoteles betrachtet werden $k{\ddot{o}}nnte$.

• Korean Journal of Labor Studies
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• v.24 no.3
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• pp.143-178
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• 2018

This study is aimed at empirically examining the Korean unionists' solidarity using the survey of 476 full-time workers employed at the unionized workplace. It also questions the determinants affecting the unionist' willingness to be united with the contingent workers. The Korean unionism has faced the biggest challenge, that is, the crisis-in-worker solidarity. Although prior literature has noted the crisis in Korean unionism, it lacks a solid investigation of individual workers' perception of solidarity which may play a key role in building up worker-solidarity in the union movement. This study first examines the three sources of solidarity allowing for the historical and theoretical approach to the modern solidarity; economic interests, worker-identification and empathy, which provide an emprical framework for this study. The empirical evidences shows dynamic aspects as of how the full-timers perceive solidarity with the non-regular workers in the three terms of solidarity. First, full-time unionists share rare willingness to be united with contingent workers in terms of economic solidarity. In addition, the KCTU (Korean Confederation of Trade Unions) with social reformative orientation has little influence on increasing their member's orientation towards solidarity. Second, it is found that full-time unionists have more willingness to identify themselves with the non-regular workers as a member of the labor class. The KTCU is also positively associated with their member's will of identification with contingent workers. Third, the unionists, however, show little empathy toward non-regular workers, which is contrast to the willingness to worker identification. No causality is also found between the KTCU and their members' empathy for the others.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.247-257
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• 2018

Background/Aims: The aim of this study was to analyze the trend of the prevalences of atrophic gastritis (AG) and intestinal metaplasia (IM) from 2011 to 2016~2017 in Korea. And, the risk factors of AG and IM were compared between 2011 and 2016~2017. Materials and Methods: A total of 4,023 subjects in 2011 and 2,506 subjects in 2016~2017 were enrolled. AG and IM were diagnosed on the basis of endoscopic findings. Multivariate analysis was performed for risk factors of AG and IM. Seventeen factors were analyzed. Results: The seroprevalence of Helicobacter pylori decreased from 2011 (59.8%; 2,407/4,023) to 2016~2017 (51.6%; 1,293/2,506; P<0.001). The prevalence of AG decreased from 2011 to 2016~2017 (P=0.018), but that of IM increased (P<0.001). The risk factors of AG in 2011 were male sex, old age, H. pylori immuoglobulin G (IgG) positivity, family history of gastric cancer (GC), and high-salt diet. For IM in 2011, the risk factors were male sex, old age, H. pylori IgG positivity, and family history of GC. Risk factors of AG in 2016~2017 were old age, H. pylori IgG positivity, and country of residence. For IM in 2016~2017, the risk factors were male sex, old age, family history of GC, high fasting glucose level (${\geq}126mg/dL$), H. pylori IgG positivity, and low income level. Conclusions: The difference in prevalence trends of AG and IM between 2016~2017 and 2011 could be the result of the different risk factors of AG and IM, such as decreased prevalence of H. pylori infection.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.417-426
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• 2018

Food preservatives are very important food additives for the biological and chemical safety of processed foods. The purposes of this study were to investigate Korean consumer's perception and information needs on food preservatives, to develop an educational booklet as a risk communication material on food preservatives, and to assess the educational effect of the developed booklet. To understand perception on food preservatives, a self-administered questionnaire survey was conducted by 381 parents having elementary school students at Seoul and Geoynggi area in Korea. Based on the survey results, brain storming of the authors along with consultation from the professionals, we developed a risk communication booklet about food preservatives. It was exposed to 35 parents of elementary school children, and their evaluation was collected by using a questionnaire and analyzed statistically. Respondents considered food safety (44.8%) as the most important factor while purchasing processed foods. They still perceived food additives as the most hazardous one (41.5%), and among those, food preservatives were the most concerned (45.9%). Total 67.7% of the respondents considered the consumption of food preservatives as hazardous or very hazardous. However, 90.6% of respondents did not have any educational experience about food additives and food preservatives. Based on their information needs, a science-based booklet consisting of the definition, classification, safety, intake, and management of food preservatives was developed. When the booklet titled as 'Food preservatives, Just Know Them!' was exposed to the parents via elementary school teacher, their negative perceptions on food additives and food preservatives were changed positively by increasing the understanding level on preservatives from 18.9% to 90.9% and obtaining 72.7% positive answers on their safety. Therefore, it could be used as an effective risk communication material on food preservatives.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.985-994
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• 2018

Bio-heavy oil for power generation is a product made by mixing animal fat, vegetable oil and fatty acid methyl ester or its residues and is being used as steam heavy fuel(B-C) for power generation in Korea. However, if the fuel supply system of the fuel pump, the flow pump, the injector, etc., which is transferred to the boiler of the generator due to the composition of the raw material of the bio-heavy oi, causes abrasive wear, it can cause serious damage. Therefore, this study evaluates the fuel characteristics and lubricity properties of various raw materials of bio-heavy oil for power generation, and suggests fuel composition of biofuel for power generation to reduce frictional wear of generator. The average value of lubricity (HFRR abrasion) for bio-heavy oil feedstocks for power generation is $137{\mu}m$, and it varies from $60{\mu}m$ to $214{\mu}m$ depending on the raw materials. The order of lubricity is Oleo pitch> BD pitch> CNSL> Animal fat> RBDPO> PAO> Dark oil> Food waste oil. The average lubricity for the five bio-heavy oil samples is $151{\mu}m$ and the distribution is $101{\mu}m$ to $185{\mu}m$. The order of lubricity is Fuel 1> Fuel 3> Fuel 4> Fuel 2> Fuel 5. Bio-heavy oil samples (average $151{\mu}m$) show lower lubricity than heavy oil C ($128{\mu}m$). It is believed that bio-heavy oil for power generation is composed of fatty acid material, which is lower in paraffin and aromatics content than heavy oil(B-C) and has a low viscosity and high acid value, resulting in inhibition of the formation of lubricating film by acidic component. Therefore, in order to reduce friction and abrasion, it is expected to increase the lubrication of fuel when it contains more than 60% Oleo pitch and BD pitch as raw materials of bio-heavy oil for power generation.

• Journal of Bio-Environment Control
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• v.28 no.1
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• pp.46-54
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• 2019

Experiments of local cooling and heating on crown and root zone of forcing cultivation of strawberry 'Seolhyang' using heat pump and root pruning before planting were conducted. During the daytime, the crown surface temperature of the crown local cooling treatment was maintained at $18{\sim}22^{\circ}C$. This is suitable for flower differentiation, while those of control and root zone local cooling treatment were above $30^{\circ}C$. Budding rate of first flower clusters and initial yields were in the order of crown local cooling, root zone local cooling and control in root pruning plantlet and non pruning plantlet, except for purchase plantlet. Those of root pruning plantlet were higher than those of non pruning plantlet. These trends were evident in the yield of the first flower cluster until February 14, 2018, and the effect of local cooling and root pruning decreased from March 9, 2018. The budding rates of the second flower cluster according to the local cooling and root pruning treatments were not noticeable compared to first flower cluster but showed the same tendency as that of first flower cluster. In the heating experiment, root zone local heating(root zone $20^{\circ}C$+inside greenhouse $5^{\circ}C$) and crown local heating(crown $20^{\circ}C$+inside greenhouse $5^{\circ}C$) saved 59% and 65% of heating fuel, respectively, compared to control(inside greenhouse $9^{\circ}C$). Considering the electric power consumption according to the heat pump operation, the heating costs were reduced by 55% and 61%, respectively.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.94-99
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• 2019

The objective of this study is to establish the shelf life of non-pasteurized whole egg, egg yolk and egg white liquid. Each sample was stored for two weeks at $5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$, and then sensory, microbial, and physicochemical tests were performed periodically. The estimation of shelf life was based on the microbial standards of total viable counts and coliforms. The chemical properties highly correlated with the sensory evaluation were also used. Our results showed that the shelf life was the most influenced by microbial properties. Exceptionally, however, whole egg and white liquid stored at $5^{\circ}C$ and $10^{\circ}C$ with limited bacterial growth were affected by chemical property. The shelf life of the three non-pasteurized liquids was calculated to be less than one day at over $15^{\circ}C$. At $5^{\circ}C$ and $10^{\circ}C$, the shelf life was calculated to be 5 d and 1 d for egg yolk liquid, 5 d and 5 d for egg white, and 7 d and 5 d for whole egg, respectively. Therefore, it is advisable to establish reasonable shelf life in the more specific manner based on consideration of these findings.