• Journal of Korean Institute of Industrial Engineers
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• v.21 no.2
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• pp.167-181
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• 1995

We develop an analytical model to estimate the time a workpiece spends in both input and output queues in trip-based material handling systems. The waiting times in the input queues are approximated by M/G/1 queueing system and the waiting times in the output queues are estimated using the method discussed in Bozer, Cho, and Srinivasan [2]. The analytical results are tested via simulation experiment. The result indicates that the analytical model estimates the expected waiting times in both the input and output queues fairly accurately. Furthermore, we observe that a workpiece spends more time waiting for a processor than waiting for a device even if the processors and the devices are equally utilized. It is also noted that the expected waiting time in the output queue with fewer faster devices is shorter than that obtained with multiple slower devices.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.489-497
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• 2000

The M/M/1 queue with impatient customers is studied. Impatient customers wait for service only for limited time K/0 and leave the system if their services do not start during that time. Notice that in the analysis of virtual waiting time, the impatient customer can be considered as the customer who enters the system only when his/her waiting time does not exceed K. In this paper, we apply martingale methods to the virtual waiting time and obtain the expected period from origin to the point where the virtual waiting time crosses over K or reaches 0, and the variance of this period. With this results, we obtain the expected busy period of the queue, the distribution, expectation and variance of the number of times the virtual waiting time exceeding level K during a busy period, and the probability of there being no impatient customers in a busy period.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.4
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• pp.306-316
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• 2004

We present a closed form approximate analytical model to estimate the expected waiting times for the storage and retrieval requests of an automated storage/retrieval (AS/R) system, assuming that the storage/retrieval (S/R) machine idles either at the rack or at the input/output point. The expected waiting times (and the associated mean queue lengths) can play an important role to decide whether the performance of a stable AS/R system is actually acceptable, to determine buffer size (or length) of the input conveyor, and to compute the number of the rack openings which is required to hold the loads which are requested by processing machines but waiting in the rack to be retrieved by the SIR machine. This model can be effectively used in the early design stage of an AS/R system.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.289-294
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• 2004

We consider M/G/1 queue in which the customers are classified into n+1 classes by their impatience time. First, we analyze the model of two types of customers; one is the customer with constant impatience duration k and the other is patient customer. The expected busy period of the server and the limiting distribution of the virtual waiting time process are obtained. Then, the model is generalized to the one in which there are classes of customers according to their impatience duration.

• Quality Improvement in Health Care
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• v.8 no.1
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• pp.56-72
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• 2001

Background : To shorten processing time for variety of medical affairs of the patient at the outpatient clinic of a big hospital is very important to qualify medical care of the patient. Therefore, patient's waiting time for medical examination is often utilized as a strong tool to evaluate patient satisfaction with a medical care provided. We performed this study to investigate factors delaying related with waiting time for medical examination. Methods : The data were collected from June 26 to July 30, 1999. A total 275 case of medical treatment and 5,634 patients who visited outpatient clinics of a tertiary hospital were subjected to evaluate the waiting time. The data were analyzed using frequency, t-test, ANOVA, $X^2$-test by SPSS Windows 7.5 program. Results : The mean patient's waiting time objectively evaluated ($30.9{\pm}33.9$ min) was longer than that subjectively by patient evaluated ($25.1{\pm}26.2$ min). Patient waiting time objectively evaluated was influenced by the starting time of medical examination, consultation hours, patients arriving time etc, as expected. The time discrepancy between two evaluations was influenced by several causative factors. Regarding the degree of patients accepted waiting time with the medical examination is 20 min. Conclusion : The results show that, besides the starting time of medical examination, consultation hours and patients arriving time, influence the patient's subjective evaluation of waiting time for medical examination and his satisfaction related with the service in the big hospital. In order to improve patient satisfaction related with waiting time for medical examination, it will be effective examination rather than to shorten the real processing time within the consultation room.

• Korea Journal of Hospital Management
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• v.8 no.2
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• pp.49-69
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• 2003

This study purported to evaluate the performance of the appointment system for outpatients in primary care dental clinic. The data of patients' time flow for 1,245 patients in Y Dental Clinic were collected for one month in 2002 and then analyzed. Specifically, the time periods of treatment and patients' waiting as well as rates of appointment and it's failure are estimated. The accuracy of expected treatment time period was also evaluated. The results showed that 72% of patients visited the clinic with appointments, and only 56% kept their appointments. The patient's waiting time period turned out to be 11 minutes in Y clinic. The expected treatment time period is turned out to be very important because they influence significantly on patient's waiting time period. Practically, the expected treatment time period should be overestimated about 9 minutes in general, and the characteristics of dentist, each patient's diagnosis and age need to be especially considered. Hospitals and clinics also need to make the systematic and detailed critical pathways for a variety of patient cases by analyzing the patients' treatment pattern. With the improved appointment systems, healthcare institutions will approach the goal of effective and efficient management of the institution and also satisfy their customers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.7-12
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• 2016

In general, crowded places, such as banks, government offices and hospitals, require the customer to wait for a certain period of time. Thus according to the order of the wait, customers takes waiting numbers. In this way, so customers should always check the order of waiting processes that they can not carry on another affairs. In this paper, we develop an application, that is SmartQ, managing queue using a mobile handset. SmartQ is an easy-to-use application allowing customers an alternative to the classic queue management systems. With this application, they are aware of the waiting conditions in real time for each of their services. They can indicate the time they wish to come and take a virtual ticket in the queue. It provides service notification, the number of waiting person, and expected waiting time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.18-29
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• 2022

Since the operation of an reft-turn actuated signal driven mainly by vehicles may increase the waiting time for walking, this signal causes inconvenience or stress to pedestrians. Therefore, in this study, the change in waiting time for walking before and after the application of an reft-turn actuated signal and the stress on the pedestrians were investigated through a questionnaire. The investigation showed that the waiting time for walking increased by 37% during non-peak time. Also the waiting time for walking of 62.1% of pedestrians became longer and 78% of them were stressed because of it. Meanwhile, simulation(VISSIM) showed that the vehicle travel speed slightly decreased to 1.07km/h(a 2.5% decrease), and the average waiting time for walking decreased by 15.51sec(a 28% decrease) with a pedestrian priority actuated signal. Therefore, it is expected that the pedestrian priority actuated signal can reduce the waiting time for walking and relieve pedestrian stress.

• Journal of Korea Water Resources Association
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• v.47 no.5
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• pp.447-457
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• 2014

This research focuses on the changes of return period for nonstationary rainfall data in which exceedance or nonexceedance probability varies depending on time. We examined two definitions of return period under nonstationarity and also performed nonstationary frequency analysis using the nonstationary Gumbel model to investigate variations of return period in Korea. Seogwipo, Inje, Jecheon, Gumi, Mungyeong, and Geochang were selected as subject sites of application. These sites have a trend in rainfall data as well as having more than 30 years data. As the results of application, the return periods considering nonstationarity are different with those considering stationarity. The differences of return periods between nonstationarity and stationarity increase as growing return period increases. In addition, the return period using the expected waiting time method shows lower value than that using the expected number of event method.

• Journal of Convergence for Information Technology
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• v.8 no.4
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• pp.27-35
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• 2018

This study aimed to analyze the association among dental care consumers' responses to waiting time, hospital image, and patient satisfaction and provide basic data that could help qualitative waiting conditions management related to health care service. A survey was conducted from May 18 to June 20, 2016 in adults who had spent waiting time at dental hospitals or clinics, and the following conclusion was drawn: Hospital image was associated with the changes in reliance on dental care centers in case of long wait, the changes in reuse intentions, and the reservation system, and patient satisfaction was associated with gender, explanation of expected waiting time, the changes in reliance on dental care centers in case of long wait, the changes in reuse intentions, and the reservation system. The positive responses to waiting time was positively correlated with hospital image and patient satisfaction; the negative reaction to waiting time was negatively correlated with hospital image and patient satisfaction; and hospital image was positively correlated with patient satisfaction.