• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.77-82
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• 2020

IoT devices frequently require input resources to communicate with various sensors or IoT platforms. IoT device wastes a lot of time as idle time or waiting time to check the data of the input resource and use the input resource. In addition, IoT devices use various input resources. We compares and analyzes input idle time and input waiting time generated from hardware serial input resource, software serial input resource, digital port input resource, and analog port input resource using Arduino widely used as IoT device. In order to design the IoT device framework, it is necessary to understand the characteristics of input resources and to design them to minimize unnecessary input idle time and input waiting time. The analog input wait time has a much larger input wait time than the digital input wait time, so it must be designed to receive analog information periodically at the appropriate timing. The characteristics of the input resources analyzed in this way help to design an efficient IoT device.

• 대한산업공학회지
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• 제21권2호
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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.

• 대한산업공학회지
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• 제22권3호
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• pp.313-324
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• 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.

• 한국의료질향상학회지
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• 제2권2호
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• pp.20-30
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• 1996

Background : Theoretically as the waiting-time of patient is estimated in queueing, many men and much money are needed. But being the estimation of patient s waiting-time very important in hospital service, so the continuous monitoring of waiting-time is inevitable. To verify that the estimation of waiting-time using parking time is economical, effective and continuous monitoring method and to develop utilizing the method, this study was done. Method : In parking confirmation office, the personnel of parking office wrote parking confirm time, chart number and whether medical examination and treatment finish or not in parking ticket. The next day the parking tickets were gathered and the above data were input. The input parking data were connected with the hospital outpatient file indexing chart number. Then the patient' s data for department, new patient or not, reservation or not, receipt time and payment time were retrieved. The group for finishing medical treatment were compared with that for not finishing in average time lag between confirmation and out-time for hospital. And In-time for hospital, receipt time, payment and out-time for hospital were also analyzed. Result : Confirming parking ticket, the group for finished medical treatment left hospital after 7 minutes. This result showed that the patient for finished medical treatment left hospital immediately. So parking time was reasonable to estimation of hospital-time was concluded. The time for medical treatment, diagnosis and test was constant for all patients and short for waiting time, Then I concluded that the parking time was reasonable for estimation patient's waiting time. Overall patient's waiting time was 113 minutes and new patient's time was 149 minutes, old patient's times was 109 minutes. Waiting time for reservation patient was 98 minutes and for non reservation patient was 122 minutes. The time from hospital arrival to payment was 50 minutes for the group of reservation patient and 69 minutes for non-reservation group. The time from payment to hospital leaving was 51 minutes and 56 minutes for non reservation group. The short time difference between reserved group and not reserved group from payment to hospital leaving time was due to bottle neck effect. Conclusion : The estimation of patient's waiting time using parking time was reasonable because the possession of car was common and the time for medical treatment was equal and the patient after treatment left hospital immediately. Using this method, timely, fast evaluation and continuous monitoring of the intervention effect were possible.

• 대한수학회논문집
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• 제13권3호
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• pp.603-627
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• 1998

The leaky bucket scheme is a promising method that regulates input traffics for preventive congestion control. In the ATM network, the input traffics are bursty and transmitted at high-speed. In order to get the low loss probability for bursty input traffics, it is known that the leaky bucket scheme with static leaky rate requires larger data buffer and token pool size. This causes the increase of the mean waiting time for an input traffic to pass the policing function, which would be inappropriate for real time traffics such as voice and video. We present the leaky bucket scheme with dynamic leaky rate in which the token generation period changes according to buffer occupancy. In the leaky bucket scheme with dynamic leaky rate, the cell loss probability and the mean waiting time are reduced in comparison with the leaky bucket scheme with static leaky rate. We analyze the performance of the proposed leaky bucket scheme in discrete-time case by assuming arrival process to be Markov-modulated Bernoulli process (MMBP).

• 대한산업공학회지
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• 제30권4호
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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.

• 한국경영과학회지
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• 제17권2호
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• pp.107-115
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• 1992

Many manufacturing processes involved in the fabrication and assembly of hightech components have highly variable yields that tend to complicate the production control. Under this random yield situation we develop a model to determine optimal input quantity, mean waiting time in the system and variance of waiting time in the system. An example which considers beta distribution as a yield distribution is given.

• 한국시뮬레이션학회논문지
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• 제8권2호
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• pp.1-11
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• 1999

Advanced information communication processing system mainly consists of network access subsystems and a switching system. This paper provides performance analysis of a typical network access subsystem. The network access subsystem is modeled as a queueing network including a server providing polling services. The arrival process of messages to an input buffer is regarded as a Poisson process. Performance measures such as mean input buffer length and mean waiting time of meassages are obtained through simulation, for it is impossible to calculate the performance measures using an analytical method. Hybrid simulation is used to reduce the variance of estimators. The variance reduction effect on the mean waiting time is reported.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.940-943
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• 2014

현재 기업이나 관공서 등에서 고객들은 대기표를 발권한 후 대기하며 시간을 소비하는 불편함을 겪고 있다. 이를 개선하고자 본 논문은 스마트폰과 연동하여 실시간 대기인원현황 알림서비스를 제공하는 새로운 대기표발권시스템 설계를 제안한다. 본 시스템의 설계를 위하여 발권기에 NFC 태그를 추가하여 대기정보를 입력한다. 그리고 대기표를 사용하는 기업 및 관공서들의 정보를 통합적으로 제공하고 관리하여 사용자들의 편의성을 증대시킨다. 따라서 본 시스템을 활용하면 기존 발권 시스템을 사용했을 때보다 대기시간을 효율적으로 사용할 수 있고, 발권종이를 사용하지 않음으로써 비용절감과 환경보호 효과까지 있을 것으로 보인다. 또한 애플리케이션으로 대기표 발권 취소 기능을 통해 업무 프로세스를 개선하는데 활용할 수 있다.

• 한국컴퓨터산업학회논문지
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• 제5권9호
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• pp.1005-1016
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• 2004

기존 교통신호등은 최적 교통신호주기기능을 상실했다. 기존 교통신호주기는 현시 교통주기와 30% -45% 가 일치하지 않고 있다. 본 논문에서는 평균 주행속도를 개선하고 평균 승용차 대기시간을 단축하기위해서 전자 교통신호등을 본 논문에서 제안한다. 본 논문에서는 실제 교통상황의 교통량, 출발 지연시간, 자동차속도 등의 40가지 센서 입력조건들을 저장하는 방법을 연구 중이다. 지능형 퍼지 기법을 이용하면, 서로 다른 10개의 교차로에 서 최 적의 녹색시간을 예측할 수 있다. 컴퓨터 모의실험 결과, 자동차 길이를 고려하지 않은 기존 교통신호등보다 . 오프셋 및 평균 자동차 대기시간을 줄일 수 있음이 입증되었다.