• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.611-616
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• 2003

Recently, the HFC-CATV network stand in a substructure of superhighway information network. Because of sharing up to 500 of subscribes, the Collision Resolution Algorithm needs in the upstream channel of HFC-CATV network. In order to provide Quality of Service (QoS) to users with real-time data such as voice, video and interactive service, the research of Collision Resolution Algorithm must include an effective priority scheme. In IEEE 802.14, the Collision Resolution Algorithm has high request delay because of static PNA(Priority New Access) slots structure and different priority traffics with the same probability. In order to resolve this problem, this paper proposed dynamic priority collision resolution algorithm with ternary tree algorithm. It has low request delay according to an increase of traffic load because high priority traffic first resolve and new traffic content with different probability. In the result of the simulation, it demonstrated that the proposed algorithm needs lower request delay than that of ternary tree algorithm with static PNA slots structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1324-1343
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• 2014

In recent years, the problem of spectrum mobility in Cognitive Radio (CR) Networks has been widely investigated. In order to utilize spectrum resources completely, many spectrum handoff techniques based on game theory have been proposed, but most studies only concern that users how to achieve better payoffs, without much attention to the diverse needs of users. In this paper, we propose a new channel-switching model based on game theory, using a prioritized approach to meet the diverse needs of users in two different modes (CQ and PS). At the same time, this paper proposes some acceleration techniques to reach the Nash equilibrium more efficiently. We evaluate the performance of the proposed schemes depending on priority using real channel availability measurements, and conclude that the channel quality function (CQ) mode provide better service for priority user but the plan-sorting (PS) mode can be more suitable in multiple priority users exist scene.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.3
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• pp.1-9
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• 2006

The handoff in IEEE 802.11 WLAN is a hard handoff. In hard handoff, a station has to stop the communication. As a result, the station is likely to miss some packets that arrival during the handoff process. To recover these lost packets, buffer-and-forward scheme is used. But, buffer-and-forward scheme is not efficient for real time service. In this paper, we propose new handoff scheme for real time service in home network based WLAN. The scheme uses priority queue which is recommended in IEEE 802.lie, and priority of priority queue is given to real time handoff calls. The simulation results show that the proposed scheme reduces traffic loss and transmission sequence error.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.71-80
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• 2014

This study is performed to determine the priorites of the evaluation factors for the improvement of fire emergency medical service by increasing it's efficiency to protect the people's lives effectively, and by recognizing it's mid-long term development. Based on the output of the analysis, the critical evaluation factors of the fire emergency medical services to be improved shall be identified, and shall be intended to use strategically for increasing the efficiency of all the activity in the EMT service, and also for providing the basic date to product and manage the good quality services. To calculate the priority of the evaluation factor for each level as shown on this study, AHP(anaysis hierarchy process) with pairwise comparison method is applied. According to the priority analysis for the evaluation factors in main category (evaluation zone), 'medical service professional aspect' is recognized as highest one, and 'service infrastructure aspect', 'service management aspect' are indicated in order. According to the priority analysis for the evaluation factors in evaluation index, 'professional personal arrangement' in the service infrastructure aspect, 'appropriateness and timeliness of emergency medical care' in the medical service professional aspect, and 'clinical training' in the service management aspect are respectively recognized as most important factors.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.15-20
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• 2012

As Internet protocol and wireless communications have developed, the number of different types of mobile services has increased gradually. Existing priority-computing schemes cannot satisfy the dynamic requirements of supporting multiple services in future wireless communication systems, because the currently used factors, mainly user priority, are relatively simple and lack relevancy. To solve this problem and provide the desired complexity, dynamic behavior, and fairness features of 3G and beyond 3G mobile communication systems, this paper proposes a novel cross-layer dynamic integrated priority-computing scheme that computes the priority based on a variety of factors, including quality of service requirements, subscriber call types, waiting time, movement mode, and traffic load from the corresponding layers. It is observed from simulation results that the proposed dynamic integrated priority scheme provides enhanced performance.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.12
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• pp.1947-1955
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• 1989

With the increasing complexity of cabling at sensory level in process control and manufacturing automation, field buses were introduced to replace the traditional point to point links from each sensor or acruator to its controlling equipments by a single link on which all information is transmitted seriall and multiplexed in time. In this papr, we introduce the BITBUS network as a field bus. For the service discipline of the BITBUS network, two service strategies are proposed to obtain the performance of the network. They are the equal priority cyclic service strategy and the non-equal priority cyclic service strategy. The former assigns equal priority to each node for polling and the latter assumes non-equal priority. The BITBUS network was modeled as a cyclic queueing model and it is analyzed by two methods: the Kuehn's and the Boxma's. Computer simulation was also done for the cyclic queueing model and simulation results were compared with those. Under mathematically non-analyzable environment, only the computer simulation was done. From the simulation result, in order to meet the response time requirement of 5 msec imposed by International Electrotechnical Commission when each node has the average traffic of 5000 messages/sec in manufacturing automation the number of slave nodes should be smaller than 10 at the transmission rate of 2.5 Mbps.

• Korean Journal of Community Nutrition
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• v.13 no.4
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• pp.531-539
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• 2008

The purpose of this study is to examine how nutritionists, principals and parents evaluated the importance and priorities of different selection factors for food materials suppliers in an attempt to suggest how to ensure the best supplier choice, since the selection of the best supplier was mandatory for the successful TQM of school food services. This study especially aims to develop priority alternatives based on relative rather than absolute assignments on selection of suppliers for school food service materials. To apply AHP, the selection factors of a food materials suppliers were grouped into five categories, which included quality, service, reliability, hygiene and price. And the five categories involved 28 elements. As the result, quality was considered most crucial on the whole, followed by service, reliability, hygiene and price; and food labeling in the category of quality evaluated as that of first priority in the totality evaluation elements.

• Journal of Engineering Education Research
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• v.21 no.3
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• pp.31-37
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• 2018

The purpose of this study is to develop a method to improve the quality of engineering education by using Kano's dualistic quality model and Timko's customer satisfaction coefficient. The results of the study are as follows. Firstly, the top priority for major education is improve 'smooth support of class medium' as an attractive and one-dimensional quality element, and 'use of various examples' and 'specialty improvement of major curriculum' as an one-dimensional quality element. Secondly, the top priority for general education is improve 'liberal education curriculum' as an attractive quality element 'use of various examples' as an one-dimensional quality element. Thirdly, the top priority for extra-curriculum is develop and provide 'study support program of student' and 'voluntary service'. Fourthly, the top priority for administrative service and facilities is improve 'increase of scholarship' and expand 'service of welfare facilities as dormitory and refectory' as an one-dimensional quality element.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.291-297
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• 2003

This paper considers discrete-time two-class Ge $o^{X/}$G/1 queues with preemptive repeat priority. Service times of messages of each priority class are i.i.d. according to a general discrete distribution function that may differ between two classes. Completion times are derived for the preemptive repeat identical and different priority disciplines. By using the completion time, the stability condition for our system is investigated.d.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.676-688
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• 2014

The IEEE 802.11e EDCA (Enhanced Distributed Channel Access) mechanism has been proposed to improve the QoS (Quality of Service) of various services in WLANs (Wireless Local Area Networks). By differentiating the channel access delay depending on ACs (Access Categories), this mechanism can provide the relative service differentiation among ACs. In this paper, we consider that WLAN is deployed in medical environments to transfer medical traffic and we reveal that the quality of the medical traffic (in particular, ECG signals) is significantly deteriorated even with the service differentiation by IEEE 802.11e EDCA. Also, we analyze the reason for performance degradation and show that IEEE 802.11e EDCA has difficulty in protecting the transmission opportunity of high-priority traffic against low-priority traffic. In order to assure medical-grade QoS, we firstly define the service priority of medical traffic based on their characteristics and requirements, and then we propose the enhanced channel access scheme, referred to as DIFF-CW. The proposed scheme differentiates CW (Contention Window) depending on the service priority and modifies the channel access procedure for low-priority traffic. The simulation results confirm that the DIFF-CW scheme not only assures the QoS of medical traffic but also improves the overall channel utilization.