• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.599-606
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• 2016

Many people feel uncomfortable when fitness center is crowded with people in all at the same time. So we propose exercise machines reservation system for resolving the problem that people feel uncomfortable in fitness center. In this paper, we design and implement the exercise machines reservation system that allows for users to reserve fitness equipments by using a NFC-based smart band. A user can reserve exercise machine using some reservation device. he or she will receive notifications through the smart band about when and which machine she or he will have to use. The user can do exercise with a recommended program, and can use any equipments conveniently even in a peak time because no one is waiting. Also, a manager can save cost through the efficient facility management and provide customized member management. Additionally, manager don't need to purchase other exercise machines or computers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.17-34
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• 2022

This paper develops a model for dynamic station assignment to optimize the Demand Responsive Transit (DRT) operation. In the process of optimization, we use the bus travel time as a variable for DRT management. In addition, walking time, waiting time, and delay due to detour to take other passengers (detour time) are added as optimization variables and entered for each DRT passenger. Based on a network around Anaheim, California, reserved origins and destinations of passengers are assigned to each demand responsive bus, using K-means clustering. We create a model for selecting the dynamic station and bus route and use Non-dominated Sorting Genetic Algorithm-III to analyze seven scenarios composed combination of the variables. The result of the study concluded that if the DRT operation is optimized for the DRT management, then the bus travel time and waiting time should be considered in the optimization. Moreover, it was concluded that the bus travel time, walking time, and detour time are required for the passenger.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.523-532
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• 2001

A Critical issue in the performance of a video-on-demand system is the required I/O bandwidth of the Video server in order to satisfy clients requests, and it is the crucial resource that may cause delay increasingly. Several approaches such as batching and piggybacking are used to reduce the I/O demand on the video server through sharing. Bathing approach is to make single I/O request for storage server by grouping the requests for the same object. Piggybacking is th policy for altering display rates of requests in progress for the same object to merge their corresponding I/O streams into a single stream, and serve it as a group of merged requests. In this paper, we propose a reservation-based hybrid disk bandwidth reduction policy that dynamically reserves the I/O stream capacity of a video server for popular videos according to the loads of video server in order to schedule the requests for popular videos immediately. The performance of the proposed policy is evaluated through simulations, and is compared with that of bathing and piggybacking. As a result, we know that the reservation-based hybrid disk bandwidth reduction policy provides better probability of service, average waithing time and percentage of saving in frames than batching and piggybacking policy.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.3
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• pp.13-22
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• 2013

Queueing system with scheduled arrivals is useful in many fields where both customers' waiting time and servers' operation time (utilization) are important, and arrival time of customers is possible to be controlled. In this paper, we analyzed the operation of ship maintenance with the queueing system with scheduled arrival. Based on the model presented by Pegden and Rosenshine [8], who dealt with exponential service time, we extended the service time distributions to phase-type distribution which is able to include a wide range of real stochastic phenomena. Since most activities in the military are carried out under tight control and schedule, scheduled arrival queue has quite good applicability in this area. In this context, we applied queue with scheduled arrival to the optimal booking time decision for the ship maintenance in the navy.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.185-186
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• 2018

현대 사회에서는 건강을 해치게 되면 삶의 질이 저하 될 뿐만 아니라 시간과 비용의 소모가 커져 어려움을 겪는다. 현대인들이 건강을 지키기 위한 가장 좋은 방법은 정기적으로 건강검진을 받는 것이다. 건강검진 대상자가 건강검진을 받을 때 각 단계별 검사 대기시간 및 안내를 받기 위하여 장시간 소요되는 문제가 있다. 본 논문에서는 건강검진을 받으러 온 검사자마다 간호사가 일일이 다음 검진 안내를 해주는 것에 대한 수고를 덜어 주고자 비콘을 활용한 건강검진 안내 시스템을 제안하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1346-1356
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• 2011

Transportation has been playing important role in our society by providing for people, freight, and information. However, it cuts its own throat by causing car accidents, traffic congestion, and air pollution. The main cause of these problems is a noticeable growth in the number of vehicles. The easiest way to mitigate these problems is to build new road infrastructures unless resources such as time, money, and space are limited. Therefore, there is a need to manage the existing road infrastructures effectively and safely. In this paper, we propose a road reservation scheme that provides fast and safe response for emergency vehicles using ubiquitous sensor network. Our idea is to allow emergency vehicle to reserve a road on a freeway for arriving to the scene of the accident quickly and safely. We evaluate the performance by three reservation method (No, Hop, and Full) to show that emergency vehicles such as ambulances, fire trucks, or police cars can rapidly and safely reach their destination. Simulation results show that the average speed of road reservation is about 1.09 ~ 1.20 times faster than that of non-reservation at various flow rates. However, road reservation should consider the speed of the emergency vehicle and the road density of the emergency vehicle processing direction, as a result of Hop Reservation and Full Reservation performance comparison analysis. We confirm that road reservation can guarantee safe driving of emergency vehicles without reducing their speed and help to mitigate traffic congestion.

• Journal of Navigation and Port Research
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• v.48 no.1
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• pp.27-33
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• 2024

Following the COVID-19 pandemic, congestion within container terminals has led to a significant increase in waiting time and turnaround time for external trucks, resulting in a severe inefficiency in gate-in and gate-out operations. In response, port authorities have implemented a Vehicle Booking System (VBS) for external trucks. It is currently in a pilot operation. However, due to issues such as information sharing among stakeholders and lukewarm participation from container transport entities, its improvement effects are not pronounced. Therefore, this study proposed a deep learning-based predictive model for external trucks turnaround time as a foundational dataset for addressing problems of waiting time for external trucks' turnaround time. We experimented with the presented predictive model using actual operational data from a container terminal, verifying its predictive accuracy by comparing it with real data. Results confirmed that the proposed predictive model exhibited a high level of accuracy in its predictions.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.509-512
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• 2019

최근 유용한 버스 어플리케이션이 많이 등장하였지만 사용자의 시각으로 보았을 때 버스를 이용하는 탑승객들은 아직까지도 많은 불편을 겪고 있다. 이에 본 논문에서는 버스기사가 승객을 보지 못하고 지나쳐 버리거나 승객들이 불필요한 대기시간을 낭비하지 않고, 탑승 후에도 번거롭게 하차 벨을 누르지 않게 되어 탑승객들로 하여금 보다 편리한 대중교통 이용을 할 수 있기를 기대한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.367-372
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• 2016

In a modern smart building, sensors can detect various physical conditions, such as temperature, humidity, sound, motion, and light, which can be used in medical services and security, and for energy savings. This paper presents an efficient elevator scheduling system that utilizes smart sensor technologies with radio-frequency identification, video, and floor sensors to detect the arrival of elevator users in advance. The detected information is then delivered to the elevator scheduling system via building networks. By using this information, the proposed system makes a reservation call for efficient control of the elevator's direction and time. Experiments under a spectrum of traffic conditions show that the proposed system performs better than a legacy system with respect to average wait time, maximum wait time, and energy consumption.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.3-3
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• 1992

컴퓨터 시스템의 개발 및 분석에 많이 활용되는 시뮬레이션 모델을 구축하는데 있어서 SIMSCRIT, GISS, SIMAN, SLA II등과 같은 시뮬레이션 전용언어가 많이 사용되지만, 이들은 새로운 전용언어의 습득, 시스템 프로그램과의 접속, 시뮬레이션 수행 속도면에서 부담을 주어왔다. 본 연구에서는 기존의 C언어 사용자들이 손쉽게 시뮬레이션 모델을 구축할 수 있도록 기존의 smpl을 확장하여 SMPLE(smpl extended)를 개발하였다. SMPLE의 모체의 smpl은 컴퓨터 시스템의 시뮬레이션 모델을 구현하기 위해 MIT에서 C언어를 이용하여 고안되었으며, C언어의 기능적인 확장으로서 라이브러리 함수들의 집합 형태를 갖는 시뮬레이션 서브 시스템이다. 이러한 라이브러리 함수들의 집합인 smpl 시뮬레이션 서브 시스템은 C언어 자체와 더불어 사건중심(event-oriented) 시뮬레이션 언어를 구성하며, smpl 시뮬레이터는 C 언어 프로그램으로 구현되다. smpl은 시뮬레이션하기 위한 설비(facility)들을 정의, 예약, 해제하거나 상태를 알아보는 함수를 제공하며, 시간의 관점에서 보면 토큰의 흐름은 일련의 대기시간과 활동시간에 의하여 나타낼 수 있게 된다. smpl은 사건의 스케쥴링(scheduling), 확률변수의 생성, 통계자료 수집 등에 관한 함수의 제공과, 시뮬레이션 시간의 전진과 사건발생의 순서를 조절해주는 기능을 제공한다. smpl 시뮬레이션 프로그램은 초기화루틴, 제어루틴 및 결과출력루틴으로 구성된다. 기존의 smpl에서 사용되는 프로그램의 자료구조(data structure)는 배열과 인덱스 구조가 사용되었다. 이러한 구조는 이미 완성되어 있는 프로그램 내에서는 효율성 면에서 좋겠지만, 변경이나 확장하기 위해 이 프로그램을 분석한다거나 필요한 기능을 추가하기 위해서는 매우 많은 어려움이 따르게 된다. 본 논문에서는 배열을 기반으로 하고 있는 smpl의 자료구조를 C의 structure와 pointer를 기반으로 하게끔 변경시키고 이에 따르는 제반 변경 사항을 수정 보완하여 프로그램의 분석을 용이하게 하며 기능의 변경 및 추가가 수월하게 하였고 메모리를 동적으로 관리할 수 있게 하였다. 또한 기존의 smpl에 디버깅용 함수 및 설비(facility) 제어용 함수를 추가하여 시뮬레이션 프로그램 작성을 용이하게 하였다. 예를 들면 who_server(), who_queue(), pop_Q(), push_Q(), pop_server(), push_server(), we(), wf(), printfct() 같은 함수들이다. 또한 동시에 발생되는 사건들의 순서를 조종하기 위해, 동시에 발생할 수 있는 각각의 사건에 우선순위를 두어 이 우선 순위에 의하여 사건 리스트(event list)에서 자동적으로 사건들의 순서가 결정되도록 확장하였으며, 설비 제어방식에 있어서도 FIFO, LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다.