• 전자공학회논문지A
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• 제31A권2호
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• pp.9-17
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• 1994

This paper proposes Double queue threshold QLT(Queue Length Threshold) algorithm and Hysteresis effect QLT algorithm. as being DPS(Dynamic Priority Scheduling) techniques. in order to advance the processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed through computer simulations,and the priority scheduling is analyzed using a retrial queue with two types of calls. Our simulation results show that the performance of the proposed Double queue length threshold QLT algorithm is superior to that of the conventinal QLT algorithm for 2 or more classes delay sensitive traffics. Also we find that Hysteresis effecT QLT algorithm is better mechanism than that of the existing QLT for real time and non-real time traffics.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2014년도 추계학술발표대회
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• pp.227-230
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• 2014

LTE 3GPP standard defines several QCI (QoS Class Identifier) classes to provide differential QoS, depending on the requirements of different user applications.These QCI values have been characterized in terms of priority, packet loss and delay budget. In spite of the availability of this robust QoS framework in LTE, there is no such scheduling algorithm that has its working principle based on this framework. The responsibility of fulfilling the user requirements, while satisfying the service class requirements is left upon the cellular service provider and it is an open issue at present. To solve this problem, we have proposed a MAC scheduler, which defines the priority of different users based on their bearer specification and provides desired QoS in terms of the achieved throughput through the resource block allocation based on calculated user priority.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1265-1278
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• 2017

Dynamic task scheduling is one of the most popular research topics in the cloud computing field. The cloud scheduler dynamically provides VM resources to variable cloud tasks with different scheduling strategies in cloud computing. In this study, we utilized a valid model to describe the dynamic changes of both computing facilities (such as hardware updating) and request task queuing. We built a novel approach called Policy Iteration Scheduling (PIS) to globally optimize the independent task scheduling scheme and minimize the total execution time of priority tasks. We performed experiments with randomly generated cloud task sets and varied the performance of VM resources using Poisson distributions. The results show that PIS outperforms other popular schedulers in a typical cloud computing environment.

• 전기학회논문지
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• 제56권12호
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• pp.2262-2264
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• 2007

In this paper, we propose a distributed opportunistic scheduling scheme for wireless LAN network. Proportional fair scheduling is one of the opportunistic scheduling schemes and used for centralized networks, whereas we design distributed proportional fair scheduling (DPFS). In the proposed DPFS scheme, each receiver estimates channel condition and calculates independently its own priority with probabilistic manner, which can reduce excessive probing overhead required to gather the channel conditions of all receivers. We evaluate the proposed DPFS using extensive simulation and simulation results show that DPFS obtains up to 23% higher throughput than conventional scheduling schemes and has a flexibility to control the fairness and throughput by controlling the system parameter.

• ETRI Journal
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• 제29권3호
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• pp.259-269
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• 2007

The ubiquitous flexible operating system (UbiFOS) is a real-time operating system designed for cost-conscious, low-power, small to medium-sized embedded systems such as cellular phones, MP3 players, and wearable computers. It offers efficient real-time operating system services like multi-task scheduling, memory management, inter-task communication and synchronization, and timers while keeping the kernel size to just a few to tens of kilobytes. For flexibility, UbiFOS uses various task scheduling policies such as cyclic time-slice (round-robin), priority-based preemption with round-robin, priority-based preemptive, and bitmap. When there are less than 64 tasks, bitmap scheduling is the best policy. The scheduling overhead is under 9 ${\mu}s$ on the ARM926EJ processor. UbiFOS also provides the flexibility for user to select from several inter-task communication techniques according to their applications. We ported UbiFOS on the ARM9-based DVD player (20 kB), the Calm16-based MP3 player (under 7 kB), and the ATmega128-based ubiquitous sensor node (under 6 kB). Also, we adopted the dynamic power management (DPM) scheme. Comparative experimental results show that UbiFOS could save energy up to 30% using DPM.

• 한국컴퓨터정보학회논문지
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• 제25권1호
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• pp.21-27
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• 2020

본 논문에서는 전투관리체계의 QoS를 향상시키기 위해 동적 가중 결손 라운드로빈과 우선 순위 기반의 혼합 스케줄링 알고리즘을 제안한다. 제안된 알고리즘인 DWDRR은 큐의 트래픽과 중요도에 따라 가중치를 동적으로 부여하여 패킷을 전송하는 방법이다. 제안된 알고리즘의 타당성을 분석하기 위해 모의실험을 통해 제안된 알고리즘이 특정구간에서 높은 효율성을 나타내는 것을 증명하였다. 따라서 기존의 알고리즘과 제안된 알고리즘을 혼합하여 사용하는 방법을 제안한다. 또한, 빈번한 기법 전환을 방지하기 위해 히스테리시스 기법을 적용하였다. 제안한 알고리즘은 동일한 트래픽에서 기존 알고리즘보다 낮은 패킷 손실률과 지연 시간을 나타낸다.

• 인터넷정보학회논문지
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• 제9권3호
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• pp.59-67
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• 2008

본 연구에서는 의료서비스의 복잡한 스케줄링문제 해결을 위한 새로운 시스템을 제안하였다. 기존 FCFS 시스템은 병원의 입장만 고려하였으나 제안 시스템은 병원의 사정과 환자들의 선호시간을 자동협상으로 반영하였다. 본 시스템은 개인의 서비스이용 희망시간을 우선도로 표현하였고 개인이 선택한 협상전략에 따라 변화되는 우선도를 기준으로 스케줄을 조정할 수 있도록 설계하였고 병원의 정책에 따라 스케줄을 확정 할 수도 있게 하였다. 따라서 제안시스템은 장비의 유휴시간만을 고려하는 기존시스템과 달리 장비의 효율성뿐만 아니라 환자의 대기시간까지 고려할 수 있도록 하여 의료서비스의 고객만족경영을 지원할 수 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1302-1320
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• 2015

In cloud, everything can be provided as a service wherein a large number of users submit their jobs and wait for their services. hus, scheduling plays major role for providing the resources efficiently to the submitted jobs. The brainwave of the proposed ork is to improve user satisfaction, to balance the load efficiently and to bolster the resource utilization. Hence, this paper roposes an Adaptive Multilevel Scheduling System (AMSS) which will process the jobs in a multileveled fashion. The first level ontains Preprocessing Jobs with Multi-Criteria (PJMC) which will preprocess the jobs to elevate the user satisfaction and to itigate the jobs violation. In the second level, a Deadline Based Dynamic Priority Scheduler (DBDPS) is proposed which will ynamically prioritize the jobs for evading starvation. At the third level, Contest Mapping Jobs with Virtual Machine (CMJVM) is roposed that will map the job to suitable Virtual Machine (VM). In the last level, VM Scheduler is introduced in the two-tier VM rchitecture that will efficiently schedule the jobs and increase the resource utilization. These contributions will mitigate job iolations, avoid starvation, increase throughput and maximize resource utilization. Experimental results show that the performance f AMSS is better than other algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권8호
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• pp.3201-3223
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• 2020

Wireless communication has become the promising technology in the recent times because of its applications in Internet of Things( IoT) devices. The IEEE 802.15.4e has become the key technology for IoT devices which utilizes the Time-Slotted Channel Hopping (TSCH) networks for the communication between the devices. In this paper, we develop a Two Level Scheduling Algorithm (TLSA) for scheduling multiple packets with different arrival rate at the source nodes in a TSCH networks based on the link activated by a centralized scheduler. TLSA is developed by considering three types of links in a network such as link i with packets arrival type 1, link j with packets arrival type 2, link k with packets arrival type 3. For the data packets arrival, two stages in a network is considered.At the first stage, the packets are considered to be of higher priority.At the second stage, the packets are considered to be of lower priority.We introduce level 1 schedule for the packets at stage 1 and level 2 schedule for the packets at stage 2 respectively. Finally, the TLSA is validated with the two different energy functions i.e., y = e^ax - 1 and y = 0.5x² using MATLAB 2017a software for the computation of average and worst ratios of the two levels.

• 정보과학회지
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• 제5권1호
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• pp.04-10
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• 1987

本 論文은 단일 processor를 가진 computer time sharing system의 運用 에 關한 것이다. 서로 다른 K 종류의 task들이 各各 獨立的이고 time-homojeneous한 Poisson分布를 따라 System에 들어 오고 있다. 또한, task 가 配當된 quantum동안 process를 받고 난후 이미 주어진 確率에 의해, 써어비스 를 完了받고 System을 離脫하기도 하고, 未完結된 경우 다른 種類의 task로 바뀌 어져 다시 process를 받기 爲해 待期한다고 한다. 이러한 여러종류의 task를 相對 로 한 time sharing model에서는 各種類의 完結에 必要한 process time의 길이에 의해 各種類의 順位(priority)가 一方的으로 決定된 것이 通例이었다. 本 硏究에서 는 各 種類의 順位를 결정하는데 있어서, 좀더 現實的인 諸條件을 반영키 위해, 各種類의 完決에 要하는 process time의 길이 뿐만 아니라, 그들의 重要度 그리고 또 緊急度까지도 고려한 새로운 Schedulign rule을 개발하였다. 또한 이 새로운 Scheduling rule에 의해 順位를 決定하는 Algorithm도 수록하였다.