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대기모형에서 효율적인 가동기간의 기대값 산출 방법에 관한 연구
송민구(Min Koo Song),박정기(Jung Ki Park) 한국자료분석학회 2001 Journal of the Korean Data Analysis Society Vol.3 No.2
In this study, a controllable M / G / 1 queuing model operating under the dyadic Min ( N, T ) policy is considered. In such a queueing systems, a server is removed from the system to perform other tasks when there are no customers in the system. Then, the removed server is reactivated immediately after the number of customers in the system reaches N for the first time or T time units elapse after removal of the server, whichever comes first. The expected busy period, which corresponds to the length of time between an activation and the next removal of the server, has been derived analytically by various ways. Since it is very difficult to apply the result to various areas and to determine the optimal values of decision variables because of its complexities. As an alternative to overcome such problems, the expected busy period is analyzed numerically in this study. For this purpose, a simple relationship model to compute the expected busy period is developed. This model could then be applied to many areas easily as well as to provide possibilities for derivation of the optimal operating policy which minimizes the total expected cost per unit time in system operations. 본 논문에서는 이변수 Min(N,T)운용방침 하에서 작동되는 조정 가능한 M/G/1 대기행렬 모형을 연구한다. 대기행렬 시스템에서 서버는 시스템 내에 고객이 한 명도 없을 때 다른 임무를 수행하도록 시스템으로부터 이동된다. 그리고 이동된 서버는 첫 번째 단위 시점 또는 서버로 이동한 후 경과되는 T 단위시점에 대해서 어느 쪽이 우선이든지 간에 시스템 내에 고객의수가 N에 도달하면 재개된다. 활성화와 서버이동 사이의 차기 단계 기간에 대응하는 가동기간의 기대값은 다양한 분석적 방법을 사용하고 있다. 왜냐하면 다양한 분야의 결과를 적용하는 것뿐만 아니라 자체의 복잡성 때문에 의사결정변수의 최적값을 결정하는 것이 매우 어렵기 때문이다. 이러한 문제점을 극복하기 위한 대안으로써, 본 연구에서는 가동기간의 기대값을 수치적으로 분석하기 위하여 단순관계 모형을 개발한다. 이 모형은 시스템운영에서 단위시간당 총 기대비용을 최소화하는 최적운영방침을 유도하기 위한 가능성을 제공할 뿐만 아니라 많은 분야에 손쉽게 적용할 수 있다.
쑥갓 중 metalaxyl-M과 dinotefuran 입제의 잔류 특성 및 위해성 평가
송민호 ( Min-ho Song ),유지우 ( Ji-woo Yu ),김진찬 ( Jinchan Kim ),이광헌 ( Kwanghun Lee ),고락도 ( Rakdo Ko ),금영수 ( Young-soo Keum ),이지호 ( Jiho Lee ) 한국환경농학회 2022 한국환경농학회 학술대회집 Vol.2022 No.-
Glebionis coronaria (called crown daisy) is commonly consumed in the Republic of Korea due to its unique smell. Since the Positive List System (PLS) was enforced in the Republic of Korea, Maximum Residue Limits (MRLs) of many crops have been established. However, the pesticides available for the crown daisy are still limited. In this study, the residual characteristics of metalaxyl-M and dinotefuran in crown daisy were investigated to expand the registration of pesticides. Additionally, risk assessment was performed by using the residual concentration of pesticides and dietary intake. Two pesticides were treated in soil on two levels, and samples were collected 51 days after seeding. The analytes were extracted using acetonitrile and the QuEChERS extraction packet (MgSO4 4 g, NaCl 1 g). The mixture was centrifuged at 4,000 rpm for 5 min, and the supernatant was diluted 1:1 with acetonitrile. The results for the concentration of pesticides were obtained with a high-performance liquid chromatography-triple quadrupole mass spectrometer. The quantitative methods for analytes were validated in linearity, accuracy, and precision. Daily dietary intake was obtained from Korea national nutrition statistics 2019. The residual concentration of metalaxyl-M in crown daisy were 0.09∼0.10 mg/kg (6 kg/10 a) and 0.17∼0.19 mg/kg (12 kg/10 a), respectively. The residual concentrations of dinotefuran in the crop were 0.53∼0.75 mg/kg (3 kg/10 a) and 1.17∼1.26 mg/kg (6 kg/10 a), each. The amounts of pesticides were less than the MRL specified by the Korean Ministry of Food and Drug Safety. The Hazard Index (HI) of metalaxyl-M and dinotefuran for consumers was 0.0075% and 0.2250%, respectively. For females in the age between 50∼64, the major consumer group, the HIs of the pesticides were <3%. Considering the consumption of crown daisy, they are not concidered to be of toxicological concern.
송민선(Min Sun Song),이중철(Joong Chul Lee),김수근(Soo Keun Kim) 한국발육발달학회 2010 한국발육발달학회지 Vol.18 No.3
The purpose of this study was performed to identify the relation of self-perceived health status, depression and factors affecting the stages of exercise behavior change on elderly people in a rural area. The subjects were 281 Korean adults with ages of over 65. The data were collected through a questionnaire for the adults in Jeonnam, Korea from June to July, 2009. This study was analyzed using ANOVA, Scheff`s Post-Hoc Test and Multiple Logistic Regression Analysis by SAS program. The distribution of the stage of exercise behavior change was precontemplation(26.7%), contemplation(20.7%), preparation(8.5%), action(12.8%) and maintenance(31.3%). This study showed that the perceived health status and depression according to the stage of exercise behavior change had significant differences. As a result of logistic regression analysis, the higher the number of chronic disease[Relative Risk(RR)=1.122, 95% Confidence Interval(CI) 1.001-1.258)] and the lower the score of depression (RR=0.908, 95% CI 0.844-0.977), the higher the proportion of people with the stages of exercise behavior change beyond the preparation stage.