In a group-testing method, instead of testing a sample, for example, blood individually, a batch of samples are pooled and tested simultaneously. If the pooled test is positive (or defective), each sample is tested individually. However, if negative (or good), the test is terminated at one pooled test because all samples in the batch are negative. This paper considers a queueing system with a two-stage group-testing policy. Samples arrive at the system according to a Poisson process. The system has a single server which starts a two-stage group test in a batch whenever the number of samples in the system reaches exactly a predetermined size. In the first stage, samples are pooled and tested simultaneously. If the pooled test is negative, the test is terminated. However, if positive, the samples are divided into two equally sized subgroups and each subgroup is applied to a group test in the second stage, respectively. The server performs pooled tests and individual tests sequentially. The testing time of a sample and a batch follow general distributions, respectively. In this paper, we derive the steady-state probability generating function of the system size at an arbitrary time, applying a bulk queuing model. In addition, we present queuing performance metrics such as the offered load, output rate, allowable input rate, and mean waiting time. In numerical examples with various prevalence rates, we show that the second-stage group-testing system can be more efficient than a one-stage group-testing system or an individual-testing system in terms of the allowable input rates and the waiting time. The two-stage group-testing system considered in this paper is very simple, so it is expected to be applicable in the field of COVID-19.

한문과와 같이 학습자에 따라 또는 한문 교과 이수 정도에 따라 학업 성취 수준이 크게 차이가 나는 특수한 경우에는 학생 개개인의 특성 및 차이, 숙달 및 미숙 등에 따라 개별적으로 평가 결과 를 분석하거나 보고(reporting)한다면, 이러한 자료들을 통해서 학생들은 더 나은 학습을 수행 (performance)할 수 있고 교사들은 더욱 효율적인 교수 ‒ 학습을 진행할 수 있다. 이러한 관점 하에 서 최근 교육 평가 분야에서 새롭게 주목하고 있는 인지진단모형(cognitive diagnostic model)을 소 개하고 한문과 평가에 적용해 볼 필요가 있을 것으로 판단하였다. 따라서 이번 연구에서는 최근에 새롭게 주목받고 있는 인지진단모형을 한문과 평가 연구자들에게 간단히 소개하고, 한문과 수능 문 항과 문항의 특정 속성과의 관계를 규명하여 Q행렬을 구성해봄으로써 인지진단모형의 한문과 적용 에 대한 적절성과 적용 가능성을 탐색해보고자 한다.

In this paper, we present a new way to derive the mean cycle time of the G/G/m failure prone queue when the loading of the system approaches to zero. The loading is the relative ratio of the arrival rate to the service rate multiplied by the number of servers. The system with low loading means the busy fraction of the system is low. The queueing system with low loading can be found in the semiconductor manufacturing process. Cluster tools in semiconductor manufacturing need a setup whenever the types of two successive lots are different. To setup a cluster tool, all wafers of preceding lot should be removed. Then, the waiting time of the next lot is zero excluding the setup time. This kind of situation can be regarded as the system with low loading. By employing absorbing Markov chain model and renewal theory, we propose a new way to derive the exact mean cycle time. In addition, using the proposed method, we present the cycle times of other types of queueing systems. For a queueing model with phase type service time distribution, we can obtain a two dimensional Markov chain model, which leads us to calculate the exact cycle time. The results also can be applied to a queueing model with batch arrivals. Our results can be employed to test the accuracy of existing or newly developed approximation methods. Furthermore, we provide intuitive interpretations to the results regarding the expected waiting time. The intuitive interpretations can be used to understand logically the characteristics of systems with low loading.

목 적: 여러 개의 렌즈로 구성된 광학시스템에 대한 유용한 분석 도구로서 행렬전달식의 가능성을 확인 하고, 이를 이용하여 사람 눈을 포함한 복합 광학계를 분석하였다. 대상과 방법: 굴스트란드 모형안의 각막, 수정체, 전체 광학계 및 근시성 난시안에서 가우스 결상방정식 과 행렬전달식으로 각각의 굴절력을 계산하고 그 결과를 비교분석하였다. 결 과: 가우스 결상방정식과 행렬전달식의 결과로 굴스트란드 정식모형안에서 각막굴절력은 각각 43.05D, 43.10D였고, 수정체굴절력은 19.50D, 19.50D, 전체 광학계굴절력에서는 동일하게 59.05D으로 계 산되었다. 본 연구에서 적용한 근시성 난시안인 환자의 경우, 가우스 결상방정식의 수직정점초점거리와 수평 정점초점거리는 각각 24.85 mm, 25.15 mm이며 행렬전달식의 수직정점초점거리와 수평정점초점거리는 각 각 24.84 mm, 25.14 mm로 계산되었다. 결 론: 굴스트란드 모형안의 각막, 수정체, 전체 광학계, 실제 근시성 난시안에서 가우스 결상방정식과 행렬전달식에 의한 결과의 차이가 크지 않았으며, 행렬전달식은 난시안을 포함한 좀 더 복잡한 광학계를 분 석하기에 유용함을 확인하였다.

 ,  , Temperature-related parameters of Panonychus citri (McGregor) (Acarina: Tetranychidae) development were estimated and a stage-structured matrix model was developed. The lower threshold temperatures were estimated as 8.4℃ for eggs, 9.9℃ for larvae, 9.2℃ for protonymphs, and 10.9℃ for deutonymphs. Thermal constants were 113.6, 29.1, 29.8, and 33.4 degree days for eggs, larvae, protonymphs, and deutonymphs, respectively. Non-linear development models were established for each stage of P. citri. In addition, temperature-dependent total fecundity, age-specific oviposition rate, and age-specific survival rate models were developed for the construction of an oviposition model. P. citri age was categorized into five stages to construct a matrix model: eggs, larvae, protonymphs, deutonymphs and adults. For the elements in the projection matrix, transition probabilities from an age class to the next age class or the probabilities of remaining in an age class were obtained from development rate function of each stage (age classes). Also, the fecundity coefficients of adult population were expressed as the products of adult longevity completion rate (liiongevity) by temperature-dependent total fecundity. To evaluate the predictability of the matrix model, model outputs were compared with actual field data in a cool early season and hot mid to late season in 2004. The model outputs closely matched the actual field patterns within 30 d after the model was run in both the early and mid to late seasons. Therefore, the developed matrix model can be used to estimate the population density of P. citri for a period of 30 d in citrus orchards.

This study proposes the generation mechanism of various design matrix using generalized linear model for design of experiment. Design generation method of GLM analysis, factorial design(FD) with center points, ANOVA design with lack-of-fit test, and response surface design are introduced. In central composite(CC) design, orthogonal blocking and fractional factorial design(FFD) are presented. We compare the design of Box-Benhken(BB) and face-centred central compsite design.

  The BMAP/M/N/0 queueing system operating in Markovian random environment is investigated. The stationary distribution of the system is derived. Loss probability and other performance measures of the system also are calculated. Numerical experiments whic

본 논문에서는 통신망의 트래픽 제어를 위한 무한버퍼, 단일 서버와 배치도착과정을 갖는 대기행렬 모형을 고려하였다. 또한 고객 도착 형태와 서비스의 분포는 지수분포를 배치 흐름은 포아송 정상과정 및 배치크기는 기하분포를 따른다고 가정하였다. 서비스를 받기 위해 시스템으로 들어오는 배치의 크기는 시스템의 상태에 따라서 트래픽 제어가 가능하다. 이와 같은 조건에서 시스템에 있는 고객의 수와 배치크기에 대한 결합 확률분포를 분석하였고, 행렬기법을 적용하여 시스

  A multi-server queueing system with finite buffer is considered. The input flow is the BMAP (Batch Markovian Arrival Process). The service time has the PH (Phase) type distribution. Customers from the BMAP enter the system according to the discipline of

온일도(Degree day)를 시간단위로한 쌀바구미의 행렬모형을 작성하였다. 기본행렬모형에서 측정된 계차증가율은 2.155/100DD였으며, 성충밀도는 지수함수적으로 증가하였다. 종내경쟁을 도입한 행렬모형에서 성충밀도는 수렴진동의 형태를 보였으며 69.300일도경에서 530으로 안정되었다. 주어진 실험조건에서 실험개체군의 밀도변동 모형에서 예측되는 것과 유사하였다. 그러나 초기최고밀도와 밀도변동추이에서 양자간에 차이를 보였다. 이는 주로 실험 개체군의 경우 자원의 일정성이 유지되지 않았던 데에서 유기된 결과로 생각된다.

This paper proposed a new method for estimating missing values in time series rainfall data. The proposed method integrated the two most widely used estimation methods, general linear model(GLM) and ordinary kriging(OK), by taking a weighted average of covariance matrices derived from each of the two methods. The proposed method was cross-validated using daily rainfall data at thirteen rain gauges in the Hyeong-san River basin. The goodness-of-fit of the proposed method was higher than those of GLM and OK, which can be attributed to the weighting algorithm that was designed to minimize errors caused by violations of assumptions of the two existing methods. This result suggests that the proposed method is more accurate in missing values in time series rainfall data, especially in a region where the assumptions of existing methods are not met, i.e., rainfall varies by season and topography is heterogeneous.