• 한국작물학회지
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• 제45권1호
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• pp.55-58
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• 2000

Germination of sweet and super sweet corn is lower than normal corn due to the higher sugar and lower starch contents of kernels. Sweet corn seeds are easily deteriorated in the field under the unfavorable condition, therefore it is important to identify the optimal harvesting time for seed production. This trial was conducted to investigate the responses of germination percentage of shrunken-2(sh2), brittle(bt), sugary(su), and sugary enhancer(se) hybrids in relation to harvesting dates. Eight hybrids of four different gene sweet corns were harvested at 15, 20, 25, 30, 35, 40, 45, and 50 days after silking(DAS). Germination test was performed using paper towel method. Mean germination percentages across eight hybrids showed the highest value at 45 DAS. There were significant differences among genes and within gene for germination. Shrunken-2 hybrid Mecca was higher than su hybrids for germination, indicating that sh2 would not be poorer than su Late harvesting beyond the optimal harvesting date might not be desirable because of more lodging and ear rots. Theoretical optimal harvesting date estimated from the regression equation was 40.9 DAS, however, practical date for harvesting would be a few days later than the estimated date if seedling vigor might be considered. Kernel dry weight per ear showed similar response to germination. Regression equation showed the highest kernel dry weight at 40.7 DAS. Significant correlations between kernel dry weight and germination were observed, impling that kernel dry matter accumulation would be an important factor for germination.

• Management Science and Financial Engineering
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• 제18권1호
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• pp.1-12
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• 2012

In this paper, we report a case study on the common due-date assignment and scheduling problem in a paper remanufacturing system that produces corrugated cardboards using collected waste papers for a given set of orders under the make-to-order (MTO) environment. Since the system produces corrugated cardboards in an integrated process and has sequence-dependent setups, the problem considered here can be regarded as common due-date assignment and sequencing on a single machine with sequence-dependent setup times. The objective is to minimize the sum of the penalties associated with due-date assignment, earliness, and tardiness. In the study, the earliness and tardiness penalties were obtained from inventory holding and backorder costs, respectively. To solve the problem, we adopted two types of algorithms: (a) branch and bound algorithm that gives the optimal solutions; and (b) heuristic algorithms. Computational experiments were done on the data generated from the case and the results show that both types of algorithms work well for the case data. In particular, the branch and bound algorithm gave the optimal solutions quickly. However, it is recommended to use the heuristic algorithms for large-sized instances, especially when the solution time is very critical.

• Journal of Preventive Medicine and Public Health
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• 제53권3호
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• pp.164-167
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• 2020

Objectives: As of March 3, 2020, the Shincheonji religious group accounted for the majority of Korean cases of coronavirus disease 2019 (COVID-19). Nonetheless, the most likely cause of the broad spread of COVID-19 among members of the Shincheonji religious group remains largely unknown. Methods: We obtained data of laboratory-confirmed cases related to the Shincheonji religious group from press releases by Korean public health authorities and news reports. We measured the period from the date of illness onset to the date of COVID-19 confirmation. Results: We analysed data from 59 cases (median age, 30 years). The estimated median period between the date of symptom onset and the date of COVID-19 confirmation was 4 days (95% confidence interval, 1-12). Conclusions: There was a delay in COVID-19 confirmation from the date of illness onset among the cases linked to the Shincheonji religious group. This delay likely contributed to the occurrence of many cases of COVID-19 in the group.

• The Plant Pathology Journal
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• 제28권2호
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• pp.172-184
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• 2012

An infection risk model for Phytophthora blight on chili pepper was developed to estimate the first date of disease occurrence in the field. The model consisted of three parts including estimation of zoosporangium formation, soil water content, and amount of active inoculum in soil. Daily weather data on air temperature, relative humidity and rainfall, and the soil texture data of local areas were used to estimate infection risk level that was quantified as the accumulated amount of active inoculum during the prior three days. Based on the analysis on 190 sets of weather and disease data, it was found that the threshold infection risk of 224 could be an appropriate criterion for determining the primary infection date. The 95% confidence interval for the difference between the estimated date of primary infection and the observed date of first disease occurrence was $8{\pm}3$ days. In the model validation tests, the observed dates of first disease occurrence were within the 95% confidence intervals of the estimated dates in the five out of six cases. The sensitivity analyses suggested that the model was more responsive to temperature and soil texture than relative humidity, rainfall, and transplanting date. The infection risk model could be implemented in practice to control Phytophthora blight in chili pepper fields.

• Management Science and Financial Engineering
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• 제19권1호
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• pp.29-36
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• 2013

This paper considers common due-date assignment and scheduling on parallel machines. The main decisions are: (a) deter-mining the common due-date; (b) allocating jobs to machines; and (c) sequencing the jobs assigned to each machine. The objective is to minimize the sum of the penalties associated with common due-date assignment, earliness and tardiness. As an extension of the existing studies on the problem, we consider sequence-dependent setup times that depend on the type of job just completed and on the job to be processed. The sequence-dependent setups, commonly found in various manufacturing systems, make the problem much more complicated. To represent the problem more clearly, a mixed integer programming model is suggested, and due to the complexity of the problem, two heuristics, one with individual sequence-dependent setup times and the other with aggregated sequence-dependent setup times, are suggested after analyzing the characteristics of the problem. Computational experiments were done on a number of test instances and the results are reported.

• 대한산업공학회지
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• 제28권4호
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• pp.415-424
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• 2002

Semiconductor manufacturing has been emerged as a highly competitive but profitable business. Accordingly it becomes very important for semiconductor manufacturing companies to meet customer demands at the right time, in order to keep the leading edge in the world market. However, due-date oriented production is very difficult task because of the complex job flows with highly resource conflicts in fabrication shop called FAB. Due to its cyclic manufacturing feature of products, to be completed, a semiconductor product is processed repeatedly as many times as the number of the product manufacturing cycles in FAB, and FAB processes of individual manufacturing cycles are composed with similar but not identical unit processes. In this paper, we propose a production scheduling and control scheme that is designed specifically for semiconductor scheduling environment (FAB). The proposed scheme consists of three modules: simulation module, cycle due-date estimation module, and dispatching module. The fundamental idea of the scheduler is to introduce the due-date for each cycle of job, with which the complex job flows in FAB can be controlled through a simple scheduling rule such as the minimum slack rule, such that the customer due-dates are maximally satisfied. Through detailed simulation, the performance of a cycle due-date based scheduler has been verified.

• 한국컴퓨터정보학회논문지
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• 제18권10호
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• pp.193-198
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• 2013

본 논문에서는 다양한 앱의 종류 중에서 유통 기한과 관련 있는 앱을 조사하고 이를 화장품 관리에 적용하는 방안을 제시하고자 한다. 이를 위해 화장품의 안전성과 안정성을 향상시키는 안드로이드 기반 앱을 설계 구현하도록 한다. 화장품은 종류가 워낙 많기 때문에 이를 잘 알고 쓰기가 무척 어려울 뿐만 아니라 각 화장품마다 구입 시기 및 개봉 시기가 각각 다르기 때문에 이를 효율적으로 관리해 주는 앱이 필요하다. 본 연구는 화장품의 유통 기한을 관리해 주는 앱을 설계 구현하므로써, 화장품의 안전한 사용을 도와주며, 화장품 업체와의 연계를 통해서 좋은 화장품의 정보를 제공 받는 것을 목표로 하고 있다.

• 유통과학연구
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• 제21권3호
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• pp.93-100
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• 2023

Purpose: The purpose of this paper is to confirm whether stocks belonging to the distribution industry in Korea have reversals, following large daily stock price changes accompanied by large trading volumes. Research design, data, and methodology: We examined whether there were reversals after the event date when large-scale stock price changes appeared for the entire sample of distribution-related companies listed on the Korea Composite Stock Price Index from January 2004 to July 2022. In addition, we reviewed whether the reversals differed depending on abnormal trading volume on the event date. Using multiple regression analysis, we tested whether high trading volume had a significant effect on the cumulative rate of return after the event date. Results: Reversals were confirmed after the stock price shock in the Korean distribution industry and the return after the event date varied depending on the size of the trading volume on the event day. In addition, even after considering both company-specific and event-specific factors, the trading volume on the event day was found to have significant explanatory power on the cumulative rate of return after the event date. Conclusions: Reversals identified in this paper can be used as a useful tool for establishing a trading strategy.

• 한국축산식품학회지
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• 제43권6호
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• pp.1002-1016
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• 2023

This study aimed to develop appropriate temperature management practices and provide scientific evidence to support the development of sell-by-date guidance for eggs. Washed and unwashed eggs were subjected to storage under six different scenarios, and both types of eggs were stored at temperatures up to 35℃ to evaluate the sell-by-date. Despite temperature fluctuations or continuous storage at 30℃ for 5 days, subsequent storage at 10℃ resulted in significantly higher Haugh unit and yolk index on day 15. These results indicate that refrigerating eggs from retail sales until consumption is effective for egg quality management, despite the exposure of up to 35℃ during distribution. In terms of sell-by-date evaluation, washed eggs retained class B quality for an additional 37 days beyond the recommended sell-by-date at 15℃, which is above the regulated storage temperature. However, unwashed eggs maintained class B quality for approximately 20 days at 30℃-35℃, emphasizing the need for sell-by-date guidelines for unwashed eggs. This study is the first to provide appropriate egg-handling practices based on the actual distribution environment in Korea.

• Journal of Preventive Medicine and Public Health
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• 제21권1호
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• pp.70-81
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• 1988

우리 나라의 최근 농촌 지역에서의 출생 신고의 법정 기간내 신고율과 출생 신고의 정확도를 알아보기 위해 경북 군위군에 거주하는 모든 유배우 가임 여성 4,014명을 1985년 4월 1일부터 1987년 3월 31일까지 2년간 면보건요원들이 추적 조사하여 찾아낸 모든 출생아 766명의 출생일자와 1987년 9월 30일자로 면사무소의 주민 등록 대장을 열람하여 얻은 동기간내 출생한 것으로 신고된 944건의 출생 신고 기록을 대조하였다. 추적 조사한 766명중 576명(75.2%)이 출생후 6개월 이내에 신고된 것으로 확인되었으며 96명 (12.5%)은 출생신고를 하였다고 진술하였으나 기록이 없었다. 추적 조사에 등록되어 있고 생후 6개월 이내에 출생신고가 확인된 576명의 법정 신고 기간인 30일 이래 신고율은 61.3%였다. 법정 기간내 신고율은 산모의 연령이 20세 미만이거나 35세 이상인 경우, 교육 수준은 국민학교 졸업자에서 그리고 출산 순위가 늦을수록 낮았다. 출생 월별 신고율은 10월부터 3월 시아의 출생아가 4월에서 9월 사이의 농번기의 출생아에 비해 높았다. 신생아기에 사망한 7명은 모두 출생 신고를 하지 않았다. 추적 조사에 등록되어 있고 6개월 이내에 출생 신고가 확인된 576명의 실제 출생 연월일과 주민등록표의 출생 연월일의 일치율은 78.0%였고 6.8%는 실제 출생일보다 더 이른 날짜로 신고되어 있고 15.3%는 더 늦은 날짜로 신고되어 있었다. 일치율은 산모의 연령이 35세 이상인 경우에 54.5%로 그리고 출산 순위가 4순위 이상일 때 56.3%로 특별히 낮았다. 또 산모의 학력이 높을수록 일치율이 높았으며, 남아가 여아보다 높았다. 3월에 출생한 경우에 실제 출생일보다 이른 날짜로 신고하는 율이 17.4%로 다른 달에 비해 높았고 이들은 대부분이 음력으로 신고하였는데 이것은 취학 연령을 고려한 것으로 생각된다. 최근 우리 나라 농촌 지역의 법정 기간내 신고율 및 신고의 정화도는 향상되고 있으나 아직도 선진국에 비해 낮은 편이며 출생 신고 자료에 의한 영아 사망률은 매우 부정확한 실정이다. 법정 기간내 신고율과 신고 내용의 정확도를 높히기 위해 분만 개조를 한 의료인으로 하여금 부모의 주소지로 직접 출생 신고를 하도록 하고 비의료인에 의한 가정 분만의 경우에는 현행 신고 제도대로 하는 것이 권장된다.