• 한국농공학회지
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• 제16권4호
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• pp.3600-3610
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• 1974

Experimental work of batch-type dryer was conducted to develop its optimurm operating conditions by analyzing the major factors which affect the drying performance. A laboratory batch-type dryer was constructed and tested for various levels of heated-air rates, and depths of grain deposit. Tong-il rice variety having the initial moisture content of approximaely 23 per cent in wet basis was used for the experiment. The criteria selected for establishing the optimum operating condition were the drying performance rate, the thermal efficiency, and the operational cost of the dryer. The results of the study are summarized as follows: 1. The performance rate of dryer for a specific operating condition was defined as total amount of material dried per hour when the moisture content of grains in the upperlayer reaches to 16 per cent in wet basis. The optimum operating conditions as viewed in the rate of drying performance could be justified by functional realtionship between the depth of grain deposit and air flow rate. In other words, there was a definite depth of grain deposit for a given air-rate which make the dryer performance maximum. The optimum grain depth for the batch-type dryer with 3.3㎡ loading area and with the attached axial fan was about 35cm. 2. The thermal efficiency for the dryer was evaluated by the ratio of the latent heat required to evaporate the grain moisture to the heat input required to raise the ambient air-temperature to 40 degree centigrade. The optimum operating condition as viewed in term of thermal efficiency analyzed was that grater depth and lower air flow-rate may be desirable. This condition is contracted with the optimum condition as viewed by the dryer performance rate. 3. The annual operating cost of batch-type dryer was analyzed for different annual hour of use and for different operation condition. The optimum condition as viewed in terms of operating cost was almost identical to one as viewed in terms of dryer performance rate. Therefore, the most economical use of batch-type dryer for the same annual operating hours can be obtained when the dryer operated in the condition of maximum dryer performance rate. Increasing the annual operating hour may be desirable to cut down the dryer operation cost, since the annual hour of dryer use is much sensitive to the operating cost than any peractical conditions of dryer operation. 4. The most desirable operational condition as justified by combining all the criteria, dryer performance rate, thermal efficiency and annual operating cost, could be concluded to operate the dryer in the condition of maximum performance rate. The condition in general is identical to the lowest operation cost for a given annual operating hour.

• 한국IT서비스학회지
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• 제17권1호
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• pp.121-134
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• 2018

Massive Open Online Course (MOOC) is online education that anyone can register for free and has internet access. MOOC is also called Education Revolution and is spreading rapidly all over the world. Although recent MOOC high-quality classes may enhance the value of MOOC, MOOC learning still needs much research. Since MOOC has low learning completion rate and continuous use rate, various studies on the reasons that learners give up at the beginning of learning have not been tried yet This research is studied for the continuous intention of use of MOOC applying self-determination theory and learning flow theory based on technology acceptance model. In particular, the research are conducted for cultural difference in continuous usage of MOOC between Korean and Chinese. The research results show that self-determination theory applying perceived autonomy, perceived competence, and perceived relatedness and learning flow is useful to explain continuous use of MOOC. The research also shows that Hofstede theory works well in explaining the cultural difference between Korea and China in continuous usage of MOOC. The result shows that korean is more influenced by perceived external motivation like perceived usefulness and chinese is more influenced by internal motivation like learning flow in continuous use of MOOC.

• 한국농공학회논문집
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• 제50권3호
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• pp.91-104
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• 2008

This study developed the WSM (weighted scenario method)-AHP method that can optimize the weighting value for multi-criteria to make GIS grid-based potential surface. The potential surface has been used to simulate urban expansion using distributed cellular automata model and to generate land-use planning as basic data. This study formulated the WSM-AHP method in mathematically and applied to test region, Suwon city, which located on south area from Seoul. WSM-AHP method generates potential map for each pair of weighting value for all criteria, which one criterion is weighted with high weighting value and the others use low weighting value, considering that the summation for all criteria weighting values should be "1". The potential change rate to the step of weighted scenario for weighting value of criteria is standardized like AHP intensity matrix in this study. From the standard potential change rate, WSM-AHP intensity matrix is completed, and then the optimal weighting value is calculated from the maximum eigenvector of the WSM-AHP matrix, according to the new WSM-AHP method developed in this study. The applied results of new method showed that the optimal weighting value from WSM-AHP is more resonable than the general AHP specialists' evaluation for weighting value. The another new finding of this study is to suggest the deterministic approach to optimize the weighting value for the distributed CA model, which is used to find new city area and to generate rational land-use planning.

• 한국치위생학회지
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• 제22권6호
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• pp.513-520
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• 2022

Objectives: The objective of the study was to investigate the factors related to non-use of interdental care products (ICP) in adolescents. Methods: The 2019 Korean Youth Risk Behavior Web-based Survey was used, examining 57,303 subjects. Complex-sample chi-square test and logistic regression analyses were performed to identify differences in ICP according to sociodemographic characteristics and oral health behavior and to determine the factors related to non-use. Results: The ICP non-use rate was 70.9%. Factors related to the non-use of ICP were middle or low economic status (OR=1.367 and 1.677). The other significant variables were less than one tooth brushing per day (OR=1.542), no scaling within 12 months (OR=1.631), and receiving dental treatment either once or two times or more (OR=1.757 and 2.195). Conclusions: To increase the ICP usage rate, continuous attention is needed from schools and families in addition to interventions at the national level.

• 한국정보시스템학회지:정보시스템연구
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• 제32권3호
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• pp.117-132
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• 2023

Purpose The purpose of this study is to analyze the impact of policy changes in Busan's local currency, Dong Baek Jeon, on the use of Dong Baek Jeon. In particular, this study tried to investigate consumption changes due to changes in local currency policy depending on the region, industry, and consumer characteristics. Design/methodology/approach This study used the transaction data of Dong Baek Jeon franchise for analysis. Specifically, the data from January 2022 to December 2022 were used to analyze the current status of the use of Dong Baek Jeon and changes in consumption before and after policy changes. Findings As a result of the analysis, the consumption of Dong Baek Jeon tended to be concentrated in specific regions, industries, and ages. In most regions and ages, the top consumption industries were similar. The use of Dong Baek Jeon showed a clear change in the pattern of use depending on policy changes. Specifically, when the benefits were revised downward, the use of Dong Baek Jeon decreased, and when it was revised upward, it increased. Depending on the policy change, the rate of increase and decrease by region and consumer characteristics was relatively similar, but it was confirmed that there was a difference in the rate of increase and decrease depending on the industry.

• 생명과학회지
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• 제33권8호
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• pp.639-650
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• 2023

가열담배(heated tobacco products, HTPs) 에어로졸 내 유해 성분들의 수준은 담배 연기와 비교해 현저히 낮은 것으로 보고되었지만, HTPs 사용이 담배 흡연과 연관된 심혈관 위험을 완화할 수 있는지는 불분명하다. 현재 연구는 습관성 흡연자들을 대상으로 담배 흡연에서 HTPs 사용으로의 단기간 전환이 심장 자율신경조절(cardiac autonomic regulation, CAR)에 미치는 영향을 탐색하기 위한 목적으로 수행되었다. 건강한 20대 남성 흡연자 7명은 5일 동안 담배 흡연(cigaette smoking, CS), 3가지 서로 다른 HTPs 사용(IQOS use, IQ; lil SOLID use, LS; lil HYBID use, LH) 혹은 흡연 중단(non-smoking, NS)으로 구성된 개방표지, 무작위 교차설계 시험을 완료했다. 각 세션은 1주의 세척 기간으로 분리되었으며, 세션당 할당된 제품 사용 전과 사용 후 24, 48, 72, 96 및 120시간에서 생체 이물[CO (carbon monoxide) and COHb (carboxyhemoglobin)], 혈류역학적 변인(systolic and diastolic blood pressure) 및 CAR 조절을 반영하는 HRV (heart rate variability) 지표들의 수준이 평가되었다. 호기 CO 및 COHb 수준은 NS에서만 통계적으로 유의하게 감소했다. 모든 세션 내 혈류역학적 변인에서 통계적 변화는 없었다. 그러나r HRV 스펙트럼 분석에서 lnHF (log-transformed high frequency, lnHF)는 NS를 포함한 IQ와 LS에서 유의하게 증가하였으며, HFnu (normalized HF)는 NS와 LH에서 통계적으로 증가하였다. lnHF와 HFnu는 각각 세션 간 시간에 따른 유의한 상호작용효과를 나타냈다. 현재 연구는 습관성 흡연자들에게서 HTPs 사용으로의 단기간 전환이 담배 흡연에 의한 심장 미주신경 긴장도 저하를 개선하여 CAR에 영향을 미칠 수 있음을 시사한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.60-65
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• 1994

In this study, the dynamic characteristics of a turbine-meter-type flowmeter is investigated by making use of the remote instantaneous flow rate measurement method (RIFM). The results of the frequency response test indicated that the gain of the flow rate of the turbine-meter-type flowmeter relative to the flow rate of the RIFM was nearly unity up to 40Hz and the phase lag of the flow rate became 90 degrees at 70Hz.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1995년도 학술대회
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• pp.109-112
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• 1995

A rate control strategy in the MPEG is critical to the quality of the reconstructed image sequence. In this paper, were propose a rate control algorithm which can improve the coding performance for a given bit constraint. The proposed algorithm use the distortion-rate curve for the fine adjustment of the quantization scaling factor of each region. This algorithm can also handle the problem due to scene change effectively. It can be easily applicable to existing MPEG coders. Simulation results show that the performance for the algorithm is better than the rate control algorithm in the MPEG-2 TM5.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2015년도 춘계 종합학술대회 논문집
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• pp.17-18
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• 2015

To improve urban safety there is an increasing social need for environmental design against crime, which is defined as the creation of inconvenient environments or situations for criminal offenders. By using a cluster analysis, we aimed to clarify crime occurrence patterns from the perspective of land-use. Osaka Prefecture was chosen as the study area because it has the highest crime rate in Japan. The results revealed that there are six patterns of crime occurrence, and that cities of medium-level of mixed land-use have the lowest crime rates.

• Child Health Nursing Research
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• 제14권1호
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• pp.99-110
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• 2008

Purpose: This study was done to identify the relationship between smoking, drinking and safety behavior in middle and high school students in one Korean province, North Cholla. Method: The study sample included 1,327 randomly selected middle and high school students from S-Gun area in Chonbuk Province. The data were collected using an anonymous questionnaire developed by the Ministry of Health and Welfare (2005). The data were analyzed using the SPSSWIN 15.0 program. Results: The smoking rate in the middle and high school students was 6.9%, and the drinking rate was 24.9%. The rate for seatbelt use was 49.3%, for drunk driving, 8.8%, and for riding in car driven by a drunk driver, 24.0%. The rates for seatbelt use, for drunk driving, and for riding in a drunk driver were higher in smokers and drinkers than in non-smokers and non-drinkers(p<.05). Conclusion: The smoking and drinking status of the adolescents was correlated with their safety behavior practices as they relate to seatbelt use, drunk driving, and for riding in car driven by a drunk driver. Therefore, an elementary school level program to curb student smoking and alcohol consumption is needed to prevent smoking and alcohol consumption in middle and high school students and contribute to improvement in their safety behavior practices.