• 식물분류학회지
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• 제53권1호
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• pp.1-8
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• 2023

Sustainable habitats play a significant role in determining the survival and habitat preservation of endangered species. To conserve the endangered species Iris dichotoma Pall. and its habitat in Taeanhaean National Park, we collected seeds from a natural population and germinated and propagated them in a greenhouse. In 2019, the propagated individuals of I. dichotoma were transplanted at two study sites in Taeanhaean National Park. After conservation translocation, annual monitoring was conducted from 2020 to 2022, and factors related to the survival and growth of I. dichotoma (clonal propagation rate [%], the flowering rate [%], the population density [individual/m²], the maximum leaf bundle length [height; cm], the maximum leaf bundle width [cm], and the pedicel length [cm]) were measured. According to the results of the monitoring of the flowering and fruiting periods for three years after transplantation, 82.4% of individuals in total were found to have survived. During 2020 to 2022, the mean population density (individual/m²) increased from 0.36 to 0.42 and the size of the leaf bundle length and the width both decreased compared to the corresponding figures in 2019 (p < 0.05). According to the findings here, the transplanted population of I. dichotoma is considered to have adapted successfully to its new site in Taeanhaean National Park.

• 대한수학회보
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• 제43권2호
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• pp.277-292
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• 2006

We consider a single-server queue with service time distribution of phase type where positive customers, negative customers and disasters arrive according to a Markovian arrival process with marked transitions (MMAP). We derive simple formulae for the stationary queue length distributions. The Laplace-Stieltjes transforms (LST's) of the sojourn time distributions under the combinations of removal policies and service disciplines are also obtained by using the absorption time distribution of a Markov chain.

• 대한수학회논문집
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• 제14권3호
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• pp.611-625
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• 1999

We consider ΜΑΡ/G/ 1 finite capacity queue with mul-tiple thresholds on buffer. The arrival of customers follows a Markov-ian arrival process(MAP). The service time of a customer depends on the queue length at service initiation of the customer. By using the embeded Markov chain method and the supplementary variable method, we obtain the queue length distribution ar departure epochs and at arbitrary epochs. This gives the loss probability and the mean waiting time by Little's law. We also give a simple numerical examples to apply the overload control in packetized networks.

• 한국콘텐츠학회논문지
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• 제3권3호
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• pp.55-62
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• 2003

본 논문에서는 기존의 Smoothing Scheme의 문제점을 개선한 새로운 WRR 셀 스케줄링 알고리즘을 제안한다. 제안된 셀 스케쥴링 알고리즘에서는 현재 라운드에 서비스되는 VC의 큐가 비어있을 경우 모든 VC들 중에서 할당된 가중치와 버퍼의 길이의 차이가 가장 큰 VC를 서비스한다. 이렇게 함으로써 대역 할당의 효율이 증가하는 결과를 가져온다. 또한, 모든 실시간 트래픽을 서비스한 후에 남은 멀티미디어 서비스 대역을 비 실시간 트래픽에 할당할 수 있다. 한 사이클 안에 평균 서비스 수가 증가하고 많은 셀을 서비스하게 됨으로써 총 버퍼 길이도 감소한다.

• 한국경영과학회지
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• 제29권3호
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• pp.63-78
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• 2004

This paper deals with a supplier-managed inventory(SMI) control for a two-echelon supply chain model with a service facility and a single supplier. The service facility is allocated to customers and provides a service using items of inventory that are purchased from the supplier, Assuming that the supplier knows the information of customer queue length as well as inventory position in the service facility at the time when it makes a replenishment decision, we identify an optimal replenishment policy which minimizes the total supply chain costs by reflecting these information into the replenishment decision. Numerical analysis demonstrates that the SMI strategy can be more cost-effective when the information of both customer queue length and inventory position is shared than when the information of inventory position only is shared.

• Journal of Preventive Medicine and Public Health
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• 제31권4호
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• pp.786-800
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• 1998

This study has attempted to show general characteristics of health centre directors who have served the post of directorship during the last 40 years. Of 3,000 such health centre directors, information on about 2,500 directors was collected. While average length of service for health center directors has increased, that of vacancy period has decreased. Rural areas have a shorter average length of service than the urban area. Rural areas have twice longer length of vacancy period per health center. Kangwon-do has the longest average length of vacancy period since 1980(2.79 months/year), and Daejeon has the shortest length of vacancy period(0.21 months/year). Chung-buk has no physician directors. The civil servant's rank for the directorship has promoted from the fifth level to the fourth level since 1990. A comparison between the physician director & non-physician director was made as follows : first, the proportion of physician directors had maintained rather high before 1980 s; 62.5% in 1963, 78.3% in 1970, 70.4% in 1980. It decreased to 44.1% in 1990 and 47.6% in 1997. Instead, non-physician directors has abruptly increased since 1980s (12.4% in 1980, 55.4% in 1990 and 50.8% in 1997). Second, physician directors mainly locate in the urban area(58.0% in 1997), but non-physician directors mainly in the rural area(67.2% in 1997). Third, since 1980, the average length of service for physician directors and for non-physician directors has become similar. Fourth, the mean age of physician directors is 45.1 years, and that of non-physician directors 55.7 years. The latter is 10 years older than the former.

• 한국의료질향상학회지
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• 제10권1호
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• pp.20-27
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• 2003

Background : The doctors' strike was not only a manmade disaster but also a chance to apply a new pattern of emergency medical service for patients. We hope to propose a new pattern of emergency medical service by comparing the patterns of emergency medical service given by resident and staff during the doctors' strike. Methods : We reviewed the medical records of patients who received emergency medical service in the Emergency Department(ED) of Deagu Catholic University Hospital during 3 days a week prior to the residents' strike (July 21-23, 2000) with those of patients receiving emergency medical service during the first 3 days of the residents' strike (July 28-30, 2000). We evaluated the patient's severity, the cause of the ED visit, the performance on the laboratory study, ECG, and radiological study, the disposition, and the length of ED stay. Also, we compared the collected data by presenting doctor and by patient's severity. Results : The staff performed fewer tests admitted fewer emergent and non-emergent patients than the residents. Also, the length of ED stay was shorter in both the emergent (212.76 vs. 321.40 minutes) and the non-emergent groups (117.68 vs. 171.39 minutes) for patients presenting to staff. Conclusion : It is desirable that emergency medical service is given by staff, not by resident.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1999년도 가을 학술발표논문집 Vol.26 No.2 (3)
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• pp.423-426
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• 1999

In offering a statistical end-to-end bandwidth guarantee service, typically called Assured Service, in Differentiated Serviced (Diff-Serv) framework, the biggest issue is its inconsistency. Larger profile TCP flows fail to achieve the guaranteed rate when competing with many smaller profile flows. This phenomenon, which we call "bandwidth skew", stems from the fact that larger profile flows take longer time to recover from the congestion window size backoff after a packet drop. Proposed solutions to this problem, therefore, are focused on modifying the TCP behavior. However, TCP modification is not practicable, mainly due to its large installation base. We look to other mechanisms in the Diff-Serv framework to find more realistic solutions. In particular, we demonstrate that RIO, the de facto standard packet differentiation mechanism used for Assured Service, also contributes to the bandwidth skew. Based on this new finding, we design a modified RIO mechanism called RI+O. RI+O uses OUT queue length in addition to IN and IN+OUT queue length to calculate OUT packet drop probability. We show through extensive simulation that RI+O significantly alleviates the bandwidth skew, expanding the operating regime for Assured Service.d Service.

• 한국안전학회지
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• 제27권4호
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• pp.38-42
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• 2012

This paper describes electrical fire on residential environment such as apartment and detached house caused by defect of interior wiring. We carried out experimental study on short circuit characteristics by the interior wiring length. We were measured arc current, arc energy and interrupting time of earth leakage current circuit breaker(ELB), when an interior wiring break out short circuit in residential environment. From the experiment results, the longer of the interior wiring, the magnitude of arc current decreased and the interrupting time of ELB increased. When applied the A maker's ELB, the strength of arc current and interrupting time of ELB was 254 A and 245 ms respectively at 30 m interior wiring length. In 3 m interior wiring length, arc current and interrupting time was 716 A and 4.24 ms respectively. Arc energy was dependent on the magnitude of arc current and the interrupting time of ELB, the longer the interrupting time, arc energy increasing. In this paper, minimum arc energy was 277 J using C maker's ELB and 3 m interior wiring length(arc current 283 A, interrupting time of breaker 6.28 ms). Therefore in the residential environment, short circuit caused by defect of the interior wiring lead to electrical fire.

• 한국시뮬레이션학회논문지
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• 제27권3호
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• pp.45-52
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• 2018

대기행렬에 고객 (또는 패킷 등)이 몰리는 오버로드(overload)가 발생하는 경우 긴 대기열이 발생하여 서비스 품질에 좋지 않은 영향을 줄 수 있다. 오버로드 상황에서 혼잡을 완화하기 위해 대기하는 고객숫자에 기반한 다양한 오버로드 제어 정책들이 고안, 적용되고 있다. 본 연구는 대기 중인 고객 숫자에 한계점 (threshold)을 두고, 한계점을 넘으면 서비스 속도를 빠르게 하거나 고객의 도착 간격(시간)을 증가시키는 제어정책을 대상으로 한다. 이러한 정책을 갖는 M/G/1 대기행렬에 대해 바쁜 기간(busy period)을 분석하는데, 연구결과는 비용구조가 주어졌을 때 최적 시스템 제어 정책을 찾는데 필수적이다.