• 경영과학
• /
• 제24권1호
• /
• pp.25-34
• /
• 2007

In this study, we consider stationary waiting times in finite-buffer 3-node single-server queues in series with a Poisson arrival process and with either constant or non-overlapping service times. We assume that each node has a finite buffer except for the first node. The explicit expressions of waiting times in all areas of the stochastic system were driven as functions of finite buffer capacities. These explicit forms show that a system sojourn time does not depend on the finite buffer sizes, and also allow one to compute and compare characteristics of stationary waiting times at all areas under two blocking rules communication and manufacturing blocking. The goal of this study is to apply these results to an optimization problem which determines the smallest buffer capacities satisfying predetermined probabilistic constraints on stationary waiting times at all nodes. Numerical examples are also provided.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2005년도 춘계학술대회 학술발표 논문집 제15권 제1호
• /
• pp.161-165
• /
• 2005

최적 교통 주기를 산출하기 위해서는 하위교차로에 대기차량이 얼마나 있는지를 점검해야 한다. 왜냐하면 대기차량이 상위교차로의 길이보다 크면 출발 지연 시간 및 승용차 대기시간이 발생하기 때문이다. 승용차 대기시간을 단축시키기 위해서 본 논문에서는 퍼지 신경망을 이용한 최적 연동 녹색시간 알고리즘을 제안한다. 컴퓨터 모의실험을 통해서, 서로 다른 교차로 조건을 고려하지 않은 고정 교통신호등 보다 평균 주행속도가 향상 된 것을 입증하였다.

• 대한산업공학회지
• /
• 제22권3호
• /
• pp.313-324
• /
• 1996

A new policy to determine the waiting position of an idle Automated Guided Vehicle(AGV) is proposed and its performance is compared with the existing waiting position policies. Unlike the existing policies, the queue length in the input buffer is considered in the new policy. As a result, the waiting position based on the new policy depends on the status of the system. The simulation result indicates that the proposed policy reduces the waiting time in both the input and the output buffers significantly, regardless of the number of AGVs in the system. Therefore, the manufacturing lead time can be minimized.

• 산업기술연구
• /
• 제18권
• /
• pp.355-362
• /
• 1998

The deadlock detector is a DBMS sub-component that examines periodically whether system is in a deadlock state based on lock waiting information of transactions. The deadlock detector and transactions execute concurrently in a DBMS and read and/or write the lock waiting information simultaneously. Since the lock waiting information is a shared one, we need an efficient method guaranteeing its physical consistency by using mutual exclusion. In this paper, we propose a new method that effectively guarantees physical consistency of lock waiting information. Two primary goals of our method is to minimize the processing overhead and to maximize system concurrency.

• 한국실내디자인학회논문집
• /
• 제29호
• /
• pp.203-210
• /
• 2001

Major companies have launched into the film industry since 1990s, which resulted in competition in facilities. In addition, restriction for the number of the prints was removed. Under these circumstances, the cinema has been transformed and developed from the established one-hall cinema into multiplex cinema with large-scaled halls. Contrary to the established cinema, modern cinema are a cultural place within easy access. They accommodate diverse social and cultural needs and their functions have been extending gradually. The waiting areas should not function only as the waiting space for the audience but also the places to attract the audience and provide them with various cultural and art information, and temporary restful break. For this study, the inter-relationship between the structure of the area and the audience are identified objectively by analyzing audience distribution and their routes within the area. The purpose of the study is to provide basic data about the design of the waiting area based on the findings above.

• 대한산업공학회지
• /
• 제24권4호
• /
• pp.639-647
• /
• 1998

We consider a multiclass production system processed by a single machine with cyclic order. Each part belongs to one of several classes and arrives at each queue in a Poisson process. The processing discipline at each queue is either exhaustive or gated. We introduce a new approach to analysis of mean waiting times for each queue. We formulate mean waiting times as cost functions on state of the system. The mean waiting times are obtained by solving a set of O($J^2$) linear equations, where J is the number of queues in the system. We also obtain the mean number of parts of each queue in the system at an arbitrary time. Based on this result, we plot the numerical values of the mean waiting times for several parameter settings.

• 응용통계연구
• /
• 제25권6호
• /
• pp.959-975
• /
• 2012

Each year research institutions such as the Korea Employment Information Service(KEIS), a government institution established for the advancement of employment support services, and Job Korea, a popular Korean job website, announce first job waiting times after college graduation. This provides useful information understand and resolve youth unemployment problems. However, previous reports deal with the time as a completely observed one and are not appropriate. This paper proposes a new study on first job waiting times after college graduation set to 4 months prior to graduation. In Korea, most college students hunt for jobs before college graduation in addition, the full-fledged job markets also open before graduation. In this case the exact waiting time of college graduates can be right-censored. We apply a Cox proportional hazards model to evaluate the associations between first job waiting times and risk factors. A real example is based on the 2008 Graduates Occupational Mobility Survey(GOMS).

• 한국산학기술학회논문지
• /
• 제16권12호
• /
• pp.8820-8829
• /
• 2015

최근 질병 치료과정에서 의료서비스에 대한 인식이 부각되면서 의료기관의 서비스 공간과 대기시간에 대한 연구가 활발히 진행되고 있다. 특히 종합병원 이용 시 방문자의 장시간 대기가 불가피하고, 이것은 환자에게 심리적 불안 및 부정적 감정으로 다가 올 것이다. 이는 의료소비자들의 불만을 가중시키고, 병원의 재방문 가능성을 낮추는 요인으로 작용하기 때문에 병원의 마케팅 및 이미지 제고를 위해서 대기시간의 연구가 절실한 실정이다. 따라서 본 연구는 의료서비스과정에서 발생하는 대기시간의 변수인 대기 환경과 대기 환자의 태도가 체감 대기 시간에 어떠한 영향을 주는가를 알아보고 병원 계획의 대안을 제시한 것을 연구목적으로 한다.

• 한국산업정보학회논문지
• /
• 제23권1호
• /
• pp.53-63
• /
• 2018

본 논문에서는 D-정책을 갖는 이산시간 BMAP/G/1 대기행렬시스템의 대기시간을 분석한다. 고객(또는 패킷)들은 마코비안 도착과정을 따라 집단으로 시스템에 도착하며, 유휴한 서버는 시스템에 도착한 고객집단의 서비스시간의 총합이 이미 정해놓은 임계값 D를 초과하면 시스템에 더 이상 서비스할 고객이 없을 때까지 서비스를 제공한다. 시스템의 안정상태 대기시간 분포를 변환 형태로 구하고 성능척도로서 평균값을 유도하였다. 시뮬레이션을 통하여 이론값들의 타당성을 검증하고 간단한 수치예제를 보였다.

• 중환자간호학회지
• /
• 제8권1호
• /
• pp.11-24
• /
• 2015

Purpose: The purpose of this study was to explore the experience of patients on the waiting list for kidney retransplantation. Methods: The data were collected by individual in-depth interviews of nine patients who were dialyzed after primary kidney graft dysfunction and were waiting for deceased donor kidney retransplantation. All interviews were audio-taped and transcribed, and were analyzed using a phenomenological method. Results: The findings included 5 theme clusters and 13 sub-themes. The 5 clusters were 'Diagnosed with chronic renal failure and dialysis: Broken daily life and crisis', 'Kidney transplantation: The only way to escape from dialysis', 'Kidney graft failure: Inevitable moving backward to hemodialysis', 'Self-management of re-dialysis patients: Growth through pain', and 'The waiting for kidney retransplantation: To try again in the hope of getting a new life'. Conclusion: This study provides a deep understanding of patients with dialysis who are waiting for deceased donor kidney retransplantation. On the basis of the findings of this study, health professionals can provide customized information and develop effective nursing interventions to improve the self-management of these patients.