• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2191-2204
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• 1997

An efficient packet transmit scheduling algorithm should be able to allocate the resource to each connection fairly based on the bandwidth and quality of service requirements negotiated during the call admission procedure and it should be able to isolate the effects of users that are behaving badly. In this paper, we propose an effective round-robin packet transmit scheduling mechanism, which we call the delay tolerant packet reserving scheme (DTPRS) based on delay QoS requirments. The proposed scheme can not only provide fairness and but also reduce delay, delay variation, and packet loss rate by reserving output link time slots of delay tolerant packets and assigning the reserved slotsto delay urgent packets. Our scheme is applicable to high speed networks including ATM network because it only requires O(1) work to process a packet, and is simple enough to implement.

• The KIPS Transactions:PartC
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• v.11C no.2
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• pp.253-262
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• 2004

In this paper, a session allocation algorithm for a switch with multiple shared links is proposed. The algorithm guarantees the reserved bandwidth to each service class and keeps the delay of sessions belonging to a service class as close as possible even if the sessionsare allocated to different shared links. To support these qualities of services, a new scheduling model for multiple shared links is defined and a session allocation algorithm to decide a shared link to be allocated to a new session on the connection establishmentis developed based on the model. The proposed heuristic algorithm allocates a session to a link including the subclass with the shortest (expected) delay that subclasses of the service class the session belongs to will experience. Simulation results verify that a switch with multiple shared links hiring the proposed algorithm provides service classes with fairer bandwidth allocation and higher throughput, and guarantees reserved bandwidth better than the switch hiring other session algorithms. It also guarantees very similarservice delay to the sessions in the same service class.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.629-642
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• 1996

ATM switch handles the traffic for a wide range of appliations with different QOS(Quality-of-Service) requirements. In ATM switch, the priority control mechanism is needed to improve effectively the required QOS requirements. In this paper, we propose a priority control mechanism using the cell transfer ratio type and discard threshold in order to archive the cell loss probability requirement and the delay requirement of each service class. The service classes of our concern are the service class with high time priority(class 1) and the service class with high loss priority control mechanism, cells for two kind of service classes are stored and processed within one buffer. In case cells are stored in the buffer, cells for class 2 are allocated in the stored and processed within one buffer. In case cells are stored in the buffer, cells for class 2 are allocated in the shole range of the buffer and cells for class 1 are allocated up to discard threshold of the buffer. In case cells in the buffer are transmitted, one cell for class 1 is transmitted whenever the maximum K cells for class 2 are transmitted consecutively. We analyze the time delay and the loss probability for each class of traffic using Markov chain. The results show that the characteristics of the mean cell delay about cells for class 1 becomes better and that of the cell loss probability about cells for class 2 becomes better by selecting properly discard threshold of the buffer and the cell transfer ratio according to the condition of input traffic.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.21-30
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• 2002

Nowadays the fair queuing field is studied actively for solving the unfair queuing problem which degrades the service performance of various applications on network. Above all DRR is a scheme that has lower work complexity and can be implemented easily. It guarantees the fair service by serving each queue every round Service Quantum(SQ) that includes the service deficit of the previous round. But it increases the delay by the numbers of unnecessary resetting of SQ or round circulation for the service that have the packet size over maximum several kbyte. In this paper, We propose the method that sets SQ dynamically to minimize this problem and the method that minimizes the work complexity on processing of packet. The proposed scheme minimizes the delay on various applications in enterprise environment by setting SQ dynamically and processing the packet simply.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.189-192
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• 2000

This paper presents a new DR(Dead Reckoning) algorithm in client-server-based networked virtual environment using network delay estimation. In the algorithm, a new update packet is sent to server (or client) whenever the difference of current real value and tracking value after network delay is larger than threshold. To confirm the proposed algorithm, a test network game was implemented. Through iterative field tests, we knew that this algorithm provides fair service and stability.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.11
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• pp.644-649
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• 2003

This study develops an analytical model for the delay analysis of real-time data in the token-passing service of Foundation Fieldbus(FF). Using the analytical model, this study proposes a network design scheme of FF Two design criteria are introduced in this study; one is the average delay of real-time data, and the other is the maximum allowable delay of real-time data. The network design scheme determines the network parameters that satisfies the performance requirements given by these design criteria.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.10
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• pp.511-520
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• 2007

Decay usage scheduling algorithm gives preference to processes that have consumed little CPU in the recent past. It has been widely-used in time-sharing systems such as UNIX, where CPU-intensive processes and interactive processes are mixed. However, there has been no sound understanding about the mixed effects of decay usage parameters on the service performance. This paper empirically analyzes their effects in terms of the resulting service bandwidth and delay Based on such empirical analysis, we derive the clear meaning of each parameter. Such analysis and understanding provides a basis of controlling decay usage parameters for desirable service provision as required by applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.426-435
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• 2002

In this paper we present an indoor propagation model for indoor wireless LAN service in the ISM band. We primarily use a 3D ray tracing as well as a patch scattering model in order to take into account the indoor fixtures. Therefore input parameters such as indoor environment parameters and antenna's types, polarizations are considered. As the results, we present fading characteristics and rms delay spread from time delay spread. In order to investigate the accuracy of the presented model, comparisons of predictions with measurement and simulations are performed in indoor wireless LAN service environments. The results show that measurements and simulations are very similar. Therefore in this paper, the effect of presented indoor propagation model is confirmed.

• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.69-75
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• 2012

In this paper, to provide various services of QoS, and moreover applying traffic ratio to CAC(Call Admission Control) algorithm tested how long average data rate and the average packet delay time. When CAC algorithm is not applied, traffic mixture ratio is 1:1:4:4, the FTP Service 0.4, web services 0.6, streaming service 0.7, the packet delay requirements are not satisfied. On the other hand CAC Algorithm is applied, all the service of packet delay are satisfied with arrival rate. Therefore, we can make sure that applying of CAC of traffic control WWW, FTP, Video, VoIP can guarantee the various services of QoS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.46-54
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• 2005

This paper presents an effcient mobile multicast method using the user pattern. We exploit the repetitive movement pattern of mobile node to reduce the total number of experience of graft and join procedure. We defined the locality scope by a movement pattern. While the network is included in the locality scope, the network should maintain a multicast tree even when the mobile node moves to the other network. In this way, the mobile host can receive a multicast service without a delay when it moves to the network in the locality scope later. We compare our scheme with existing schemes under the total signaling cost and the service delay time by using a discrete analytical model for cost analysis. Analytical results demonstrated that the total signaling cost and service delay time was significantly reduced through our proposed scheme.