• 한국콘텐츠학회논문지
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• 제17권3호
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• pp.589-595
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• 2017

본 논문에서는 다양한 이동통신 서비스의 원활한 데이터 전송을 위한 적정 채널 용량의 산정 방법을 제시한다. 서비스 유형별 패킷 전송에 대한 허용 지연시간 기준을 모두 충족하기 위해서는 적정한 채널용량이 확보되어야 한다. 이러한 채널 산정 과정을 분석하기 위해 디지털 통신시스템의 이산시간 운영특성과 패킷 기반 트래픽의 집단 발생 상황을 $Geo^x$/G/1 비선점형 우선순위 대기행렬로 모델링하였다. 휴리스틱한 평균 대기시간 분석 방법을 이용하여 다양한 전송 우선순위를 갖는 서비스 유형별 평균 대기시간을 도출하였다. 이를 이용하여 무선 서비스 지연에 관한 품질 척도(QoS)를 충족시키는 적정 채널 용량의 산정 과정을 제시하였다. 본 연구 결과인 적정 채널 용량 산정 방법은 이동통신 데이터 서비스의 품질 만족도를 높이고 네트워크의 경제적 운용에 도움이 될 것으로 기대한다.

• Clinics in Shoulder and Elbow
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• 제25권2호
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• pp.121-128
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• 2022

Background: To determine the reasons and factors that contribute to the cancellations of shoulder surgeries at a tertiary referral center and to analyze the characteristics of these patients. Methods: Patients scheduled for shoulder surgery from June 2017 to July 2019 were allocated to a surgery group (n=224) or a cancellation group (n=96). These groups were compared with respect to patient characteristics, types of surgery, distance from patient's home to the hospital, traveling time to the hospital, and waiting period before surgery. Reasons for cancellation and responses were acquired using a telephone interview and were subsequently analyzed. Results: The cancellation group was older, had a less frequent history of trauma, and had a lower proportion of patients undergoing arthroscopic rotator cuff repair than the surgery group (p=0.009, p=0.014, and p=0.017, respectively). In addition, mean distance from the patients' homes to the hospital and preoperative waiting time were both longer in the cancellation group (p=0.001 and p<0.01, respectively). The most common reason given for cancellation was another medical condition (28.1%). Conclusions: Older age, need for arthroscopic rotator cuff repair surgery, longer distance from the patient's home to the hospital, and longer waiting period significantly increased the chance of cancellation. The main reason for canceling surgery was a concurrent medical condition. Therefore, identification of other medical conditions in advance is an important consideration when surgeons recommend shoulder surgery to patients. Surgeons should also consider patient's age, type of surgery, distance from the hospital, and waiting time when assessing the possibility of surgery cancellation.

• 한국전자거래학회지
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• 제4권1호
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• pp.87-101
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• 1999

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the control devices located in common manufacturing zone and operated by connecting them. In this paper, functional standard of the network layers are set as physical and data link layer of IEEE 802.2, 802.4, and VMD application layer and ISO-CIM reference model. Then, they are divided as minimized architecture, designed as group objects which perform group management and service objects which organizes and operates the group. For the stability in this network, this paper measures the variation of data packet length and node number and analyzes the variated value of the waiting time for the network operation. For the method of the analysis, non-exhausted service method are selected, and the arrival rates of the each data packet to the nodes that are assumed to form a Poission distribution. Then, queue model is set as M/G/1, and the analysis equation for waiting time is found. For the evalution of the performance, the length of the data packet varies from 10 bytes to 100 bytes in the operation of the group management network, the variation of the wating time is less than 10 msec. Since the waiting time in this case is less than 10 msec, response time is fast enough. Furthermore, to evaluate the real time processing of the group management network, it shows if the number of nodes is less than 40, and the average arrival time is less than 40 packet/sec, it can perform stable operation even taking the overhead such as software delay time, indicated packet service, and transmissin safety margin.

• 한국산업정보학회논문지
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• 제29권2호
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• pp.69-80
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• 2024

본 논문에서는 대기행렬이론의 대표적인 서버제어정책 중 D-정책과 T-정책이 혼합된 상황 하에서 운영되는 이산시간 대기행렬시스템을 다룬다. 베르누이 도착과정으로 시스템에 도착하는 고객들을 단일 서버가 선입선출로 서비스하며, 시스템 내에 서비스할 고객이 없으면 서버는 휴가를 떠났다가 돌아와서 대기 중인 고객들의 서비스시간의 총합(즉, 총 일량)이 D를 초과할 때까지 반복하여 휴가를 갖는다. 본 연구에서 다루는 시스템의 운영은 2차전지를 사용하는 모바일 디바이스의 효율적인 자원 활용의 모델링에 사용할 수 있다. 또한 통신·교통 시스템 분석에 적합한 것으로 잘 알려진 이산시간 시스템을 대상으로 하여 유연한 혼합 제어정책(DT-정책) 하에서 대기행렬시스템의 안정상태 대기시간과 체재시간을 하나의 틀 안에서 유도하였다는 데 그 의의가 있다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.591-595
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• 1998

This paper proposes a new concept of optimal shortest path algorithm which reduce average vehicle wating time and improve average vehicle speed, Electro sensitive traffic system can extend the traffic cycle when three are many vehicles on the road or it can reduce the traffic cycle when there are small vehicles on the road. But electro sensitive traffic light system doesn't control that kind of function when the average vehicle speed is 10km -20km. Therefore, in this paper to reduce vehicle waiting time we developed design of traffic cycle software tool that can arrive destinination as soon as possible using optimal shortest pass algorithm. Computer simulation result proved 10%-32% reducing average vehicle wating time and average vehicle speed which can select shortest route using built in G.P.S. vehicle is better than not being able to select shortest route function.

• 대한산업공학회지
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• 제30권4호
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• pp.285-293
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• 2004

In this study, a machine grouping problem for the formation of manufacturing cells is considered. We constructed the problem as minimizing manufacturing leadtime consisting of parts' processing, moving, and waiting time. Specifically, the main objective of the defined problem is established as minimizing inter-cell traffic in order to minimize the part's moving time. In addition, to reduce the waiting time of parts, the load balance among cells is implicitly included as constraints. Since this problem is well known as NP-complete and cannot be solved in polynomial time, a genetic algorithm is implemented to obtain solutions. Also, a local optimization algorithm is applied in order to improve the solution by the genetic algorithm. Several experiments show that the suggested algorithms guarantee near optimal solutions in a few seconds.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제17권4호
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• pp.267-278
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• 2013

Through quantitative analysis of two math classroom videos, combined with the relationship between types of teachers' questioning and students' answering, it is concluded the following problems are in the mathematics classroom teaching: (1) The time of teachers' questioning is longer, the number is too much, with managerial questions and prompting questions is given priority to; (2) Teachers' questioning time is longer than students' answering time, comprehensive answer is more, creative answer is little; (3) In the classroom questioning, students' participation is low; and (4) There is a significant correlation between types of teachers' questioning and length of waiting time after questions. In response to these phenomena, we propose strategies as follows: pursuit of timeliness of classroom questioning, reducing inefficient questions, to increase efficient questions, adopting different waiting strategies for different questioning types, to mobilize students' thinking activities, and improving students' participation etc.

• 대한산업공학회지
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• 제28권3호
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• pp.247-255
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• 2002

The objective of this paper is to clarify the decomposition property for $M^{X}$/G/1 queues with generalized vacations so that the decomposition property is better understood and becomes more applicable. As an example model, we use the $M^{X}$/G/1 queue with setup time. For this queue, we correct Choudhry's (2000) steady-state queue size PGF and derive the steady-state waiting time LST. We also present a meaningful interpretation for the decomposed steady-state waiting time LST.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 춘계학술대회
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• pp.14-19
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• 2006

This study examined the effect of waiting in a service queue on the evaluation of service quality focused on its overall process, mediators and moderators The conceptual model of this paper integrates key variables derived from previous studies of consumer waiting behavior. Data obtained from actual customers in service queue at a hospital was used to test the theoretical framework. First, results from the path analysis confirm that negative affect and acceptability of the wait function as mediators in the process that the perceived duration of the wait affects customer's evaluation of overall service quality. Second, the analysis of the data, with the use of moderate regression shows that disconfirmation of wait time expectations, transaction importance, stability of wait time and wait environment work as moderate variables for the relationship between perceived duration of wait and negative affect. For the relationship between perceived wait time and acceptability of the wait, on the other hand, only transaction import ante shows a significant effect as a moderator.

• Communications for Statistical Applications and Methods
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• 제5권3호
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• pp.809-817
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• 1998

In this paper we consider a polling system where the token is passed according to a general service order table. We derive an exact and explicit formula to compute the mean waiting time for a message when the arrivals of messages are modeled by batch Poisson processes.