• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.162-167
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• 2017

A Katsuobushi smoking machine was developed and evaluated to determine its benzo(a)pyrene reducing effect. The machine was equipped with two heaters for smoking and chamber heating. The smoke-generating system was equipped with a cadmium sulfide (CdS) smoke sensor, an on/off controller, and a rotating feeder with a smoke inlet. Raw bonito was steamed and then smoked under three smoke levels. After smoking at $45^{\circ}C$ for 108 h, the benzo(a)pyrene concentrations were 5.87, 7.83, and $11.41{\mu}g/kg$ at the low, middle, and high smoke levels, respectively. The benzo(a)pyrene concentrations after low-level smoking at 45, 65, and $85^{\circ}C$ for 108 h were 5.87, 4.82, and $3.27{\mu}g/kg$, respectively. Accordingly, the optimal conditions for benzo(a)pyrene reduction were a lower smoke level and higher smoking temperature. These optimal smoking conditions can be implemented with the newly developed machine, but is not possible using a conventional Katsuobushi smoking machine.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.1000-1004
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• 2010

본 연구는 도시지역 1개 초등학교 5 6학년과 농촌지역 일개 군의 2개 초등학교 5 6학년을 대상으로 도시와 농촌 초등학교 5 6학년의 변비 유병률을 파악하고, 이와 관련된 배변행태, 식습관 및 운동 습관 요인, 스트레스 등을 분석하여, 학생들이 바람직하고 올바른 생활습관을 갖도록 하고 학생들의 변비 증상을 개선하고 예방하여 건강증진을 도모하는 기초자료로 활용하고자 시도된 단면조사연구이다. 연구대상자는 임의 추출방법에 의하여 선정된 3개 초등학교 5 6학년 재학생 총 585명을 대상으로 하였다. 연구방법은 2009년 10월에 임의로 선정된 3개 학교의 보건선생님을 통하여 연구대상자에게 설문지를 배포하여 대상자 스스로 기입하도록 하였다. 본 연구의 결과로 자가보고에 의한 변비의 유병률은 전체 22.1%로 남학생 16.9%, 여학생 27.0% 이었으며, 주중 3회 미만의 배변횟수를 변비로 정의하였을 경우 변비 유병률은 15.7%로 남학생 11.6%, 여학생 19.6%로 여학생의 변비 발생률이 높았다. 거주지역별로는 농촌 지역에 거주하는 대상자가 도시 지역에 거주하는 대상자보다 변비 발생이 높은 것으로 나타났으며 변비발생과 운동습관과의 관계에 있어서는 운동을 하지 않는 대상자가 변비 유병율이 높게 나타났다. 변비 분류에 의한 배변습관에서는 변비군에서 배변 시간이 10분 이상이 많았으며, 시험기간 중 변비경향 또는 변을 보지 못 한다가 정상군보다 높게 나타났다. 또한, 변비군의 치료관련 행태에서는 18.3%가 변비치료를 위해 변비약을 복용한 경험이 있는 것으로 조사되었으며, 배변 형태에 변화가 있을 경우 상담자로는 가족 또는 혼자 판단하는 경우가 대부분이었다. 변비 분류에 의한 배변 관련 증상의 분포는 변비군에서 항문통증 경험, 항문 출혈 경험 등이 정상군보다 높게 나타났다. 주중 3회 미만의 배변횟수를 변비로 정의 하였을 경우와 배변 관련 증상의 분포는 변비군에서 항문통증 경험, 배변 후 상쾌하지 못함 등이 정상군보다 높게 나타났다. 학교에서의 배변여부는 변비군에서 학교에서 배변을 하는 비율이 정상군보다 높았다. 변비여부를 종속변수로 하여 변비발생에 영향을 미치는 요인을 분석한 결과 성, 학년, 거주지역에서 변비발생의 위험요인으로 도출되었다. 주 3회 미만의 배변횟수를 변비라고 정의할 경우, 변비발생에 영향을 미치는 요인을 분석한 결과 성, 학년, 모직장 유무, 운동이 변비발생의 위험요인으로 도출되었다. 본 연구에서는 초등학교 5 6학년을 대상으로 배변 행태, 식습관, 스트레스, 학교에서의 배변습관 등을 조사해 본 결과 상당수 학생들의 배변 실태가 좋지 않은 것을 알 수 있었다. 바람직하지 않은 식습관, 운동 부족, 과다한 스트레스 등은 학생들의 변비 발생의 위험 요인이 될 수 있으므로 변비의 발생을 예방하기 위해서는 매일 적절한 운동을 하고 인스턴트음식과 패스트푸드섭취 등을 줄이고 올바른 생활습관 및 스트레스 관리 등이 필요하며 부모들의 자녀에 대한 관심이 더욱 필요하다. 이를 위해서 초등학교부터 변비 예방을 위한 체계적인 프로그램을 만들고, 실시하여야 하며 또한 보건교육을 통하여 건강한 생활습관을 습득하고 변비를 예방하는 노력이 필요하다 하겠다.

• Journal of KIISE:Databases
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• v.30 no.1
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• pp.64-79
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• 2003

In client-server computing environments, update transactions of spatial data have the following characteristics. First, a transaction to update maps needs interactive work, and therefore it nay take a long time to finish. Second, a long transaction should be allowed to read the dirty data to enhance parallelism of executing concurrent transactions. when %he transaction is rolled back, it should guarantee the cascading rollback of all of the dependent transactions. Finally, two spatial objects may have a weak dependency constraint, called the spatial relationship, based on geometric topology. The existing recovery approaches cannot be directly applied to this environment, due to the high rollback cost and the overhead of cascading rollbacks. Furthermore, the previous approaches cannot guarantee the data integrity because the spatial relationship, which is a new consistency constraint of spatial data, is not considered. This paper presents new recovery schemes for update transactions of spatial data. To guarantee the data integrity, this paper defines recovery dependency as a rendition of cascading rollbacks. The partial-rollback is alto suggested to solve the problem of high rollback cost. The recovery schemes proposed in this paper can remove the unnecessary cascading rollbacks by using undo-delta, partial -redo and partial-undo. Finally, the schemes are performed to ensure the correctness.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.199-228
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• 2016

This study investigates the effects of economic factors and forest environments on rural residential area development in seven north central states of the U.S. by focusing on the relative importance of not only economic factors but also forest environments by forest type as core drivers of residential development. An empirical model of locations and magnitudes of population changes since 1950 in the north central region is first constructed, and then a panel model with fixed effects for counties is used to explain population growth by age group over time at the county level. Then a set of three equations is estimated for three major age groups, and a cross-sectional model is estimated for the last time period that regresses county-level environmental amenity variables on fixed effects coefficients for counties. Finally, an equation explaining changes in rural housing density is estimated. The results imply that immigrant age is a key factor influencing the choice of the place of residence and that the effects of environmental amenity factors on population growth and subsequent housing development in a county vary according to the age group.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.13-25
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• 2016

High-speed railway (Korea Train Express) has had a deep impact on the regional economy of Korea. Current high-speed rail research is mostly theoretical, there is a lack of quantitative research using a precise algorithm to study the effect of high-speed railway on the regional economy. This paper analyses the influence of high-speed rail on the regional economy, with a focus on the Daegu area. Quantitative analysis using department store indexes and regional medical records is performed to calculate the economic influence of high-speed rail. The result shows that high-speed railway effects the regional economy though regional consumption growth and medical care trends.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.92-97
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• 2014

Perchlorate ($ClO_4^-$) is an emerging contaminant of soil/groundwater and surface water. $ClO_4^-$ has been shown to inhibit iodide uptake into the thyroid gland and cause a reduction in thyroid hormone production. $ClO_4^-$ is highly soluble and very stable in water. Biodegradation by $ClO_4^-$-reducing bacteria (PRB) is considered the most important factor in natural attenuation of $ClO_4^-$. Rivers in an industrial complex have potential to be contaminated with $ClO_4^-$ discharged from point or non-point sources. In this study, water samples were taken from the rivers running through the Gumi industrial complexes and used for batch test to analyze $ClO_4^-$-degradation potential of river microorganisms. The results of 83-h batch culture showed that $ClO_4^-$-removal efficiency of all samples was 0.77% or less without addition of an external electron ($e^-$) donor. However $ClO_4^-$-removal efficiency was higher when an $e^-$ donor (acetate, thiosulfate, $S^0$, or $F^0$) was added into the batch culture, showing up to 100% removal efficiency. The removal efficiency was various depending on type of $e^-$ donor and site of sampling. When acetate was used as an $e^-$ donor, the highest $ClO_4^-$-removal efficiency was observed among the $e^-$ donors used in this study, suggesting that activity of heterotrophic PRB was dominant. The results of this study provide basic information on natural attenuation of $ClO_4^-$ by river microorganisms. The information can be useful to prepare a strategy to enhance efficiency of $ClO_4^-$ biodegradation for in situ bioremediation.

• Journal of the Korean Chemical Society
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• v.56 no.3
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• pp.371-377
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• 2012

In this study, open inquiry reports of 165 eighth graders in Daegu were analyzed in terms of content area, the types of inquiry hypothesis, and the types of inquiry variables. Before summer vacation, students learned about inquiry process and explored their own inquiry topic for two class hours. During summer vacation, students performed open inquiry including problem selection, designing and performing experiment, data collection, data analysis, and writing report. After the vacation, students submitted their reports, and answered to additional survey regarding the source of inquiry idea, the definition of hypothesis, and the most difficult step of inquiry process. As a result, chemistry was the most dominant content area of the reports and biology and life science were the next. 130 out of 165 reports included inquiry hypotheses, and most of them were predictive hypotheses. In many reports, dependent and independent variables could not be identified because of their ambiguity. However, inquiry variables described in experimental design, which were mostly categorical variables, were clearer than those described in inquiry subject and inquiry hypothesis. The most difficult step of inquiry process for students was to generate an idea for open inquiry.

• Journal of Life Science
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• v.33 no.3
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• pp.268-276
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• 2023

This study was conducted to optimize the formulation conditions of the immediate-release layer of carvedilol in the development of a two-layer tablet formulation for carvedilol and ivabradine. Using a 2⁴+3 full-factorial design of experiments, excipients (microcrystalline cellulose, citric acid, and crospovidone) of the carvedilol immediate-release layer (wet granulation part) and process parameters for the tablet compression process (main compression) were optimized, and seven types of each dependent variable (assay, content uniformity, hardness, friability, disintegration, and dissolution [pH 1.2 and 6.8]) were evaluated using design expert software. The analysis of variance results confirmed that the main compression has a significant effect on hardness, friability, and disintegration time and that microcrystalline cellulose has a major effect on friability and dissolution. In addition, it was confirmed that citric acid has a significant effect on friability. Crospovidone affects friability and dissolution. According to the design space from the design of the experiment results, the optimized range is microcrystalline cellulose (~18.0-32.0 mg), citric acid (~0.5-12 mg), and main compression (~615-837 kgf). Consequently, this study confirmed the availability of manufacturing the carvedilol immediate-release layer in which all risk factors evaluated in the initial risk assessment are removed.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1721-1730
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• 2023

As awareness of the problem of global warming emerges around the world, the role of carbon sinks in settlement is increasingly emphasized to achieve carbon neutrality in urban areas. In order to manage carbon sinks in settlement, it is necessary to identify the current status of carbon sinks. Identifying the status of carbon sinks requires a lot of manpower and time and a corresponding budget. Therefore, in this study, a map predicting the location of trees was created using already established tree location information and Sentinel-2 satellite images targeting Seoul. To this end, after constructing a tree presence/absence dataset, structured data was generated using 16 types of vegetation indices information constructed from satellite images. After learning this by applying the Extreme Gradient Boosting (XGBoost) model, a tree prediction map was created. Afterward, the correlation between independent and dependent variables was investigated in model learning using the Shapely value of Shapley Additive exPlanations(SHAP). A comparative analysis was performed between maps produced for local parts of Seoul and sub-categorized land cover maps. In the case of the tree prediction model produced in this study, it was confirmed that even hard-to-detect street trees around the main street were predicted as trees.

• Information Systems Review
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• v.23 no.3
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• pp.177-200
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• 2021

Recently, the use of prepaid electronic payments such as electronic wallets, digital currency and prepaid points is gradually increasing. Prepaid electronic payments has the characteristic of being used after charging first. This study empirically investigated the factors affecting the intention to use online charging in order to help improve the service that require prepaid recharge by applying transformed TAM. Since there are not many previous studies for the intention to use online charging, we extract factors through preceding researches for electronic cash and mobile easy payment. Also we analyze the intention to use online charging for transportation card users, focusing on the moderating effects. As a result of the study, it was found that 'convenience', 'ubiquity', and 'self-efficacy' among the independent variables had a positive (+) effect on mediation variable 'perceived usefulness'. 'Perceived usefulness' was analyzed to have a significant influence on the dependent variable 'usage intention'. According to users' gender, internet usage time, internet shopping frequency, online charging frequency and transportation card usage type, the moderating effect was significant on 'perceived usefulness' and 'usage intention'. As an implication, it was suggested that service improvement and differentiated marketing are needed in direction of increasing the usefulness of services. Additional research directions were proposed for services such as e-wallets, prepaid points and digital currencies by adding other factors and moderate variables.