• 한국통신학회논문지
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• 제32권8B호
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• pp.547-552
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• 2007

IEEE는 E-PON에 대한 구현 표준으로 IEEE802.3ah을 제정하였으나 구체적인 상향대역할당 메커니즘에 대해서는 별도로 규정하지 않고 제조업체의 몫으로 남겨 두었다. 이에 관련 전문가들은 E-PON에서의 상향 전송에 대한 성능 개선 및 다양한 서비스 수용을 위해서 여러 방식의 상향대역할당 기법들을 연구하였다. 본 논문에서는 상향 트래픽 전송 성능을 개선하는 동적대역할당 메커니즘을 제안한다. 이 메커니즘은 ONU의 상향전송 큐별로 최소보장 상향대역을 다양하게 설정할 수 있도록 하였으며, 큐에 대기 중인 패킷을 전송하기 위하여 큐별로 가중치를 부여한 DRR(Deficit Round Robin) 기법을 적용하였다. 시뮬레이션에 의해 상향대역 이용률이 기존방식 대비 10% 이상 개선됨을 보여 주었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1481-1484
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• 1997

The vehicle driving simulator expects vehicle motion with real-time simulation arise from driver's steering, accelerating, stopping and simulates motion of vehicl with visula, audio and washout algorithm. And it gives a vivid feeling to driver in reality. Vehicle driving simulator with vehicle integration control system is used for analysis of analysis of vehicle controllaility, steering capacity and safety in various pseudo environment alike. basides, it analyzeds vehicle safety factor dirver's reaction and promotes traffic safety without driver's own risks. The main proceduress of development of the vehicle driving simulator are classified by 3 parts. first the motion base system which can be generated by the motion queues, should be developed. Secondly, real-time vehicle software which can afford the vehicle dynamics, might be constructed. The third procedure is the integration of vehicle driing simulator which can be interconnected between visual systems with motion base. In this study, we are to study of the motion base for a vehicle driving simulator design and that of its real time control and using an extra gyro sensor and accelerometers to find a position and an orientatiion of the moving platform except for calculating forward kinematics. To drive the motion base, we use National Instruments corp's Labview software. Furthemore, we use analysis module for the vehicle motionand the washout algorithm module to consummate driving simulator, which can be driven by human in reality, so we are doing experimentally process about various vehicle motion conditon.

• The Journal of the Acoustical Society of Korea
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• 제14권1E호
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• pp.73-82
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• 1995

본 논문은 relaxed min-max heap을 병합시키기 위하여 이용된 새로운 자료구조인 개선된 relaxed min-max-pair 힙으로서, 두개의 relaxed min-max 힙 즉, 크기가 n인 relaxed min-max nheap과 크기가 k인 relaxed min-max kheap으로 구성된 우선 순위 큐를 병합시키기 위한 순차적 알고리즘을 제시하고자 한다. 본 논문에서 제시된 방법은 [8]에 제시된 방법에서 relaxed min-max 힙을 병합시키기 위해서 이용된 blossomed tree와 lazying 방법을 제거하여도 병합이 되는 새로운 기법을 제시하였다. 결과적으로 본 논문에서 제세된 방법은 두개의 relaxed min-max 힙의 크기가 서로 다른 경우로서, 이때 크기 $k{\leq}{\lfloor}log(size(nheap)){\rfloor}$인 경우, 시간 복잡도가 O(log(log(n/k))*log(k)) 이고 공간복잡도가 O(n+k)임을 볼수가 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.473-494
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• 2020

To provide a guaranteed Quality of Service (QoS) to real-time traffic in High-Speed Downlink Packet Access (HSDPA) core network, we proposed an enhanced mechanism. For an enhanced QoS, a Class-Based Low Latency Fair Queueing (CBLLFQ) packet scheduling algorithm is introduced in this work. Packet classification, metering, queuing, and scheduling using differentiated services (DiffServ) environment was the points in focus. To classify different types of real-time voice and multimedia traffic, the QoS provisioning mechanisms use different DiffServ code points (DSCP).The proposed algorithm is based on traffic classes which efficiently require the guarantee of services and specified level of fairness. In CBLLFQ, a mapping criterion and an efficient queuing mechanism for voice, video and other traffic in separate queues are used. It is proved, that the algorithm enhances the throughput and fairness along with a reduction in the delay and packet loss factors for smooth and worst traffic conditions. The results calculated through simulation show that the proposed calculations meet the QoS prerequisites efficiently.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.237-239
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• 2004

Wireless LAN Voice over IP(VoIP) equipment needs Quality-of-Service(QoS) with priority for processing real-time traffic. This paper shows transmit function implementation of wireless LAN(WLANs) media access control(MAC) support VoIP, and it has an advantage of guarantee of QoS and is adaptable to VoIP or mobile wireless equipment. The IEEE 802.11e standard in progress has four queues according to four access categories(AC) for transmit and the MAC transmits the data based on EDCA. The value of AC is from AC0 to AC3 and AC3 has the highest priority. The transmit method implemented at this paper ensure QoS using one transmit FIFO in hardware since real-time traffic data and non real-time traffic data has the different priority. The device driver classifies real-time data and non real-time data and transmit data to hardware with information about data type. The hardware conducts shorter backoff and selects faster AIFS slot for real-time data than it for non real-time data. Therefor It make give the real-time traffic data faster channel access chance than non real-time data and enhances QoS.

• International Journal of Quality Innovation
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• 제6권1호
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• pp.74-97
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• 2005

IDEF0 is the IEEE standard for functional enterprise modeling and has been used for business process modeling or process mapping in US and Europe. But it does not reflect the potential benefits of modeling and simulation of the dynamic aspects of an enterprise or a system. On the other hand, simulation tools concentrate mostly on the simulation of material flows and are difficult to include information flows and control flows. Additionally, the simulation models that include elements such as queues, event generators and process nodes is a visual interactive representation for the model builder, but is inconvenient for the domain expert. In an attempt to fill that void, we provide an integration of business process and simulation models in this paper. An enhancement of the IDEF0, called parameterized IDEF0, is proposed and its conversion mechanism to network simulation model is developed. Using this methodology, business process models for alternative systems can be evaluated and compared through simulation on time, cost, and quality metrics. As an application of the proposed methodology, economic evaluation of EDI (Electronic Data Interchange) for time-based BPR (Business Process Redesign) is demonstrated. In addition to BPR, the developed methodology may be further integrated with ABC (Activity Based Costing), TQM (Total Quality Management), and economic evaluation of information systems.

• 정보처리학회논문지A
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• 제11A권3호
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• pp.213-216
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• 2004

스케줄링이나 정렬과 같은 응용에 이용될 수 있는 우선순위 큐는 포인터를 사용하는 것과 이용하지 않고 묵시적으로 표현하는 두 가지가 있다. 묵시 우선순위 큐는 메모리 이용에 있어서 포인터를 사용하는 것보다 효율적이다. 묵시 우선순위 에는 이진 트리에 근거한 전통적인 2-힙이 있는데, 이는 캐쉬 메모리를 효율적으로 이용하는 8-원 트리에 근거한 8-힙보다 느린 것으로 나타났다. 본 논문에서는 구현하기 쉽고 빠른 새로운 묵시 우선순위 큐인 8-힙＊를 제안한다. 실험을 통하여 8-힙＊가 2-힙 뿐만 아니라 8-힙보다 빠름을 보인다.

• 한국멀티미디어학회논문지
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• 제6권1호
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• pp.105-113
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• 2003

CDMA 셀룰러 시스템 내에서 고속이동체에 대한 비효율적인 채널할당으로 호 블록킹 확률이 높아진다. 이를 위하여 고속이동체의 속도에 따른 전용 채널과 큐를 할당하여 계층셀에 적용해 속도에 따른 QoS를 보장하는 방식이 제안되었다. 본 논문에서는 현재 위치한 셀에서의 이동체의 수신 신호세기에 따라 HA에 트래픽이 적을 때에 FA 내에 고속 핸드오프 전용 채널을 할당하였다 또한 FA 내 신호세기가 약한 고속 핸드오프 호에 대하여 새로운 환형 큐 LiFA를 생성하여 고속 핸드오프 호를 LiFA에 호 지속시간 동안 대기시켜 호 강제종료율을 개선하였다.

• 대한산업공학회지
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• 제21권1호
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• pp.85-101
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• 1995

Automated Guided Vehicles(AGVs) are widely used in computer integrated manufacturing(CIM) systems for material handling purposes. Although automated guided vehicles provide higher levels of flexibility and computer integrability, the installations are limited in number and one of the critical reasons lies in the complexity involved in the operation. The main objective of this research is to alleviate this problem by proposing efficient integrated operational control methods for AGV-based CIM systems. Particularly, this research is concerned with the mixed problem of dispatching automated guided vehicles and scheduling machines operation. The proposed dynamic heuristic algorithm uses various priority schemes and relevant information concerning the load of the system, the status of queues, and the position of AGVs in the scheduling process. The scheduling decision process is hierarchical in the sense that different decision criteria are applied sequentially to identify the most appropriate part to be served. This algorithm consists of two sections, the section of part selection by AGVs for the next service whenever an AGV completes the current assignment, and the section of part selection by machines for next service whenever a machine completes the current operation. The proposed algorithm has been compared with other scheduling schemes using the performance measure of mean flow-time and mean tardiness. Simulation results indicate that the proposed algorithm can reduce the mean flow-time and mean tardiness significantly.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2016년도 춘계학술대회
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• pp.269-275
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• 2016

This paper considers the arrival, airport and departure capacity as a whole, through which, the network effect between airports is fully emphasized, the flight action is coordinated, and the flight demand pattern is reasonably assigned. The optimization problem of flight queues in multi-airport is studied in detail; the mathematical model of multi-airport opening non-real time flow management in terminal area is established, and related problems such as the parameters, the simplification and the solving of the model are discussed in detail to some extent. Appropriate decision making variables are taken to make the multi-airport network system linear 0-1 integer programming model, thus, the solving of the model is available and the central flow management is realized. The heuristic implicit enumeration presented in this paper can effectively solve this kind of problems. Through the simulation of some airports network system, we not only validate the algorithm presented in this paper, but also give a deep analysis of the results, which would produce reference for later practicable use. The simulation proves that this algorithm offers a good way to settle the problem of multi-airport flight queue optimization in air traffic management automation system in terminal area.