• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.167-172
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• 1997

We present a procedure which finds the probability distribution of number of customers accumulated when the server ends a vacation in the Geo/G/1 gated queueing system, where the service for a customer and the vacation, respectively, takes one slot time. The pp. g. f. for the number of customers accumulated at the gate closing epoch is obtained as a recursive form. The full probabilities, then, are derived using an iterative procedure. This system finds an application in a packet transmitting telecommunications system where the server transmits(serves) packets(customers) accumulated at a gate closing epoch, and takes one slot time vacation thereafter.

• Journal of applied mathematics & informatics
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• v.6 no.3
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• pp.943-952
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• 1999

Models of single-server queues with vacation have been widely used to study the performance of many computer communica-tion and production system. In this paper we use the formula for a wide class of vacation policies and multiple types of vacations based on the M/G/1 queue with generalized vacations and exhaustive service. furthermore we derive the waiting times for many complex vacation policies which would otherwise be to analyze. These new results are also applicable to other related queueing models. if they conform with the basic model considered in this paper.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.29-40
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• 1999

Tourism marketing begins with understanding tourists' needs. However, understanding tourists' needs should be expressed by specific utility values rather than simple preference order for the purpose of developing tourism marketing strategies. This study aims at identifying tourist's stated preference of vacation destination attributes by using the conjoint analysis. In addition, this study is purposed to define relationship between attitude and preference, and to suggest implications to tourism marketing strategies. It was found that stated preference to such attributes as 'quality of accommondation', 'recreation activities' and 'accessibility' among the attitude segments was significantly different but stated preferences to diverse profiles made of these three attributes showed significant differences only in such attributes as 'quality of accommodation' and 'recreation activities'. This results make it possible to identify the function of preference to destination attributes in the vacation destination choice decision. It also embodies the relationship between tourist's attitude and vacation destination attributes.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.111-121
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• 2002

In this paper, we analyze an M$^{x}$ /G/1 with three types of vacation periods including setup time. Three types of vacations are : N-policy, single vacation, and multiple vacation. We consider compound poisson arrival process and general service time, where the server starts his service when a setup is completed. We find the PGF of the number of customers in system and LST of waiting time, with welch we obtain their means. A decomposition property for the system sloe and waiting time is described also.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.4
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• pp.443-457
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• 2015

We consider the M/M/c/c queues in which the customers blocked to enter the service facility retry after a random amount of time and some of idle servers can leave the vacation. The vacation time and retrial time are assumed to be of phase type distribution. Approximation formulae for the distribution of the number of customers in service facility and the mean number of customers in orbit are presented. We provide an approximation for M/M/c/c queue with general retrial time and general vacation time by approximating the general distribution with phase type distribution. Some numerical results are presented.

• Journal of Korean Library and Information Science Society
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• v.45 no.4
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• pp.21-44
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• 2014

The purpose of this study is to research and determine a systematic operating method for analyzing vacation reading guidance programs in school library systems and, thereby, suggesting ways of operating a reading guidance program both effectively and efficiently. Analyses of questionnaires going out to hundred of school libraries in Gyeonggi Province will be performed for this purpose. Specifically, the study will analyze the following 1) the current operation status of each program, 2) their initial purposes and focus, 3) targeted children groups, 4) program instructors, and 5) the actual content design of the programs. As a result, the vast majority of the school libraries operation of vacation reading guidance program and purpose of inspire of reading interest. Finally this study suggests the 5 directions to support operation of vacation reading guidance program in School Libraries. The results of this study will likely suggest the need to re-align or shift current vacation reading guidance programs to be more inclusive for all participants.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.1
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• pp.89-99
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• 2020

In this paper, we consider a dyadic server control policy that combines workload control and single vacation. Customer arrives at the system with Bernoulli process, waits until his or her turn, and then receives service on FCFS(First come first served) discipline. If there is no customer to serve in the system, the idle single server spends a vacation of discrete random variable V. If the total service times of the waiting customers at the end of vacation exceeds predetermined workload threshold D, the server starts service immediately, and if the total workload of the system at the end of the vacation is less than or equal to D, the server stands by until the workload exceeds threshold and becomes busy. For the discrete-time Geo/G/1 queueing system operated under this dyadic server control policy, an idle period is analyzed and the steady-state queue length distribution is derived in a form of generating function.

• Journal of Nutrition and Health
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• v.41 no.4
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• pp.341-352
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• 2008

The number of school lunch-supported children who belong to low-income families has been rapidly increased in Korea. This study was aimed at evaluation of nutritional status of school lunch-supported elementary school children. One hundred school lunch-supported children and 119 non-supported children of fourth to sixth year class in 3 elementary schools in Gyeongbuk rural area were selected, and surveys were conducted twice, i.e., once during school term and once during summer vacation in 2006. Food consumption survey during school term was carried out through an interview by dieticians at school-lunch time using a 24-hour recall method, and the survey during summer vacation conducted by recording food intakes for three days by children. Nutrient intakes were calculated using CAN-Pro 3.0 program. School lunch-supported children showed higher rate of skipping breakfast and rather irregular meal time as compared to non-supported students. Eating alone was more frequent in school lunch-supported children than in nonsupported children. The average nutrient intakes and nutrient adequacy ratios were lower in supported children than in non-supported children. During term, percentages of nutrient intakes provided by school-lunch were higher in supported children than in non-supported children. Intakes of energy nutrients were within acceptable macronutrient distribution ranges, but proportion of carbohydrate intake increased during vacation. Analysis of patterns of food intakes based on major food groups (dairy, meat, grain, fruit, vegetable) indicated that meals during term were more balanced as compared to meals during vacation. In conclusion, food behaviors and nutrient intakes of school lunchsupported children were inferior to those of non-supported children during term and during summer vacation. They were provided with more nutrient intakes from school lunch during term as compared to non-supported children. Therefore, it is necessary not only to keep meal support program during vacation but also to provide a proper nutrition education as a part of school lunch program to improve nutritional status and food behaviors of school lunch-supported children.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.91-105
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• 2019

Discrete-time Queueing models are frequently utilized to analyze the performance of computing and communication systems. The length of busy period is one of important performance measures for such systems. In this paper, we consider the busy period of the Geo/Geo/1/K queue with a single vacation. We derive the moments of the length of the busy (idle) period, the number of customers who arrive and enter the system during the busy (idle) period and the number of customers who arrive but are lost due to no vacancies in the system for both early arrival system (EAS) and late arrival system (LAS). In order to do this, recursive equations for the joint probability generating function of the busy period of the Geo/Geo/1/K queue starting with n, 1 ≤ n ≤ K, customers, the number of customers who arrive and enter the system, and arrive but are lost during that busy period are constructed. Using the result of the busy period analysis, we also numerically study differences of various performance measures between EAS and LAS. This numerical study shows that the performance gap between EAS and LAS increases as the system capacity K decrease, and the arrival rate (probability) approaches the service rate (probability). This performance gap also decreases as the vacation rate (probability) decrease, but it does not shrink to zero.

• Korean Journal of Community Nutrition
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• v.8 no.6
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• pp.910-918
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• 2003

The purposes of this study were to develop a model for university foodservices and to provide management strategies for reducing costs, and increasing productivity and customer satisfaction. The results of this study were as follows : 1) The demands in university food services varied depending on the time series. A fixed pattern was discovered for specific times of the month and semesters. The demand tended to constantly decrease from the beginning of a specific semester to the end, from March to June and from September to December. Moreover, the demand was higher during the first semester than the second semester, within school term than during vacation periods, and during the summer vacation than the winter. 2) Pearson's simple correlation was done between actual customer demand and the factors relating to forecasting the demand. There was a high level of correlation between the actual demand and the demand that had occurred in the previous weeks. 3) By applying the stepwise multiple linear regression analysis to two different university food services providing multiple menu items, a model was developed in terms of four different time series(first semester, second semester, summer vacation, and winter vacation). Customer preference for specific menu items was found to be the most important factor to be considered in forecasting the demand.