• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.275-282
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• 2010

This paper analyzes a discrete-time bulk-service queue with probabilistic bulk size, where the service process is interrupted by a Markov chain. We study the joint probability generating function of system occupancy and the state of the Markov chain. We derive several performance measures of interest, including average system occupancy and delay distribution.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.151-152
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• 2016

본 연구에서는 기존 연구에서 주를 이루고 있는 컨테이너터미널이 아니라 벌크터미널에 초점을 맞추어 서비스품질을 분석하고자 한다. 이를 위하여 전문가집단과 브레인스토밍을 통해 속성을 정리하고, 벌크터미널을 이용하고 있는 고객이 인지하고 있는 각 속성에 대한 서비스품질을 분석하는데 그 목적이 있다. 또한 벌크터미널을 이용하는 각 이용주체별 인식차이 비교를 통해 제공받은 서비스에 대한 속성별 만족도를 살펴본다.

• Journal of Communications and Networks
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• 제7권1호
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• pp.87-92
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• 2005

This paper presents basic queueing analysis contributing to teletraffc theory, with commonly accessible mathematical tools. This paper studies queueing systems with bulk arrivals. It is assumed that the number of arrivals and the expected number of arrivals in each bulk are bounded by some constraints B and (equation omitted), respectively. Subject to these constraints, convexity argument is used to show that the bulk-size probability distribution that results in the worst mean queue performance is an extremal distribution with support {1, B} and mean equal to A. Furthermore, from the viewpoint of security against denial-of-service attacks, this distribution remains the worst even if an adversary were allowed to choose the bulk-size distribution at each arrival instant as a function of past queue lengths; that is, the adversary can produce as bad queueing performance with an open-loop strategy as with any closed-loop strategy. These results are proven for an arbitrary arrival process with bulk arrivals and a general service model.

• 한국동물위생학회지
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• 제42권4호
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• pp.177-181
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• 2019

Q fever is a zoonosis caused by Coxiella burnetti that is important not only for livestock but also for humans. This research aims to investigate infection rate of Q fever by examining the prevalence of antibody titers in cattle in Sejong City. From March to October 2018, 505 samples of Hanwoo serum and 47 samples of bulk-tank milk were collected and analyzed using ELISA. According to the result, 25 (53.2%) out of 47 bulk-tank milk samples were antibody positive and 28 (5.5%) out of 505 cows were antibody positive. The seroprevalence of C. burnetii increased with age (<1 y=0%, 1~2 y=4.1%, 3~5 y=7.5%, ≥6 y=9.6%) and was higher in females (6.5%) compared to males (0%).

• 대한조선학회논문집
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• 제31권4호
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• pp.8-14
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• 1994

북미의 오대호 연안을 중심으로 한 inland service에서 부터 deep sea service에 까지 발전되어 증가추세에 있는 Self-Unloading bulk carrier와 관련하여, bulk cargo handling 측면에서, 다양한 bulk cargo material을 shore side 하역 설비의 지원없이 신속하게 discharge 할 수 있도록 설계되어 있는 self-unloading system의 특성 및 개요에 대하여, 그간 수차례에 걸쳐 설계 및 건조한 경험을 바탕으로 소개 및 고찰해 보고자 하였다.

• 한국통신학회논문지
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• 제28권9B호
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• pp.783-792
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• 2003

We consider a finite-buffer discrete-time queueing system with fixed-size bulk-service discipline: Geo/ $G^{B}$1/K＋B. The main purpose of this paper is to present a performance analysis of this system that has a wide range of applications in Asynchronous Transfer Mode (ATM) and other related telecommunication systems. For this purpose, we first derive the departure-epoch probabilities based on the embedded Markov chain method. Next, based on simple rate in and rate out argument, we present stable relationships for the steady-state probabilities of the queue length at different epochs: departure, random, and arrival. Finally, based on these relationships, we present various useful performance measures of interest such as the moments of number of packets in the system at three different epochs and the loss probability. The numerical results are presented for a deterministic service-time distribution - a case that has gained importance in recent years.s.

• 산업경영시스템학회지
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• 제16권28호
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• pp.39-47
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• 1993

In this paper, We develop performance evaluation model for Twin fork Automated Storage/Retrieval systems. The system is modeled as a modified bulk service queueing system consisting of one exponential server with limited system capacity. The differance between this model and general bulk service queueing model is the inequality of transition service rate of each stage. The ejective of this model is to provide system characteristics for Twin fork AS/R system design problems, which are the number of customers in system, wait time in system and queue, the system queue size.

• 한국동물위생학회지
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• 제42권2호
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• pp.61-65
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• 2019

Seroprevalence of Coxiella burnetii (Q fever) in bulk-tank milk and cattle in Daegu area was analyzed from 2017 to 2018 by ELISA. The prevalence of antibodies in collected bulk-tank milk from 12 dairy cattle farms was 41.7% (10/24) and the seroprevalence of 249 cows reared in the area of Daegu was 3.2% (8/249) By age, the seroprevalence was 1.9% (2/105) in less than 2 years of age, 4.2% (5/119) between 3 and 5 years of age and 4.0% (1/25) in more than 6 years of age. By breed, the seroprevalence of the Hanwoo cattle was 1.2% (2/162) and the seroprevalence of the dairy cattle was 6.9% (6/87). The result suggested that seroprevalence of C. burnetii was relatively high in both bulk-tank milk samples and dairy cattle than the Hanwoo cattle. Based on these data, it is necessary to keep monitoring the prevalence of Q fever in Daegu area.

• 상하수도학회지
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• 제19권4호
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• pp.487-496
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• 2005

Chlorine bulk decay tests were carried out by bottle test under controlled conditions in a laboratory. Experiments were performed at different temperatures: $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and the water temperatures when samples were taken from the effluent just before entering to its distribution system. 38 bulk tests were performed for water of Al (water treatment plant), 4 bulk tests for A2 (large service reservoir), and A3(pumping station). Residual chlorine concentrations in the amber bottles were measured over time till about 100 hours and bulk decay coefficients were evaluated by assuming first-order, parallel first-order, second-order. and $n^{th}-order$ reaction. The $n^{th}-order$ coefficients were obtained using Fourth-order Runge-Kutta Method. A good-fit by the average coefficient of determination ($R^2$) was first-order ($R^2=0.90$) < parallel first-order ($R^2{_{fast}}=0.92$, $R^2{_{slow}}=0.95$) < second-order ($R^2=0.95$) < $n^{th}-order$ ($R^2=0.99$). But if fast reaction of parallel first-order bulk decay were applied to the effluent of large service reservoir with ca. 20 hours of travel time and slow reaction in the water distribution system following the first 20 hours, parallel first-order bulk decay would be best and easy for application of water quality modeling technique.

• 한국동물위생학회지
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• 제44권1호
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• pp.11-14
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• 2021

Seroprevalence of Coxiella burnetii in cattle and goats from southern region of Korea was analyzed. From January to December 2020, 1,409 samples of bulk-tank milk, cattle serum and goat serum were collected and analyzed using ELISA. The prevalence of antibodies in collected was 72.6% (501/682), 4.1% (21/515) and 10.4% (22/212). By age, the seroprevalence of cattle was 2.4%, 4.1%, 5.3% (<2 years, 2~5 years, ≥6 years). In bulk-tank milk of dairy cattle according to region was Gyeongnam 45.5%, Gyeongbuk 77.5%, Daegu 70.0%, Jeonnam 50.0% and Chungbuk 50.0%. And seroprevalence of goats was 10.4% (22/212).