• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.747-757
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• 2010

This paper studies the Markov modeling of multiclass loss systems supporting several kinds of customers. The concept of unit for loss systems is introduced and the method of equal probability allocation among units is especially considered. Equilibrium equations and limiting distribution of the loss systems are studied and loss probabilities are computed. We analyze an example of a simple system to gain an insight about general systems.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.679-688
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• 2016

In this paper, we study multiclass loss systems with different server allocation methods. The Markovian states of the systems are defined and their effective representation is investigated. The limiting probabilities are derived based on the Markovian property to determine the performance measures of the systems. The effects of the assignment methods are compared using numerical solutions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.707-715
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• 2003

In this paper, we propose a new MAC(Medium Access Control) protocol using Movable-boundary, which tries to guarantee Qos for multimedia traffic in the slotted CDMA system. In this scheme, the traffic scheduler assigns channel resource according to the packet priority per service class and adapts the Movable-boundary concept in which the minimum resource is assigned to each traffic class; the remaining resource if it is available can be assigned dynamically according to the temporal demand of other traffic classes. For performance analysis, we performed computer simulations to obtain throughput and packet loss rate and compared the results with Fixed-boundary system. We observed that the error rate of voice traffic could be maintained below a prescribed value while bursty traffic such as video source shares the same channel. In comparison with Fixed-boundary scheme, our protocol exhibits better throughput and packet loss rate performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9A
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• pp.736-745
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• 2003

Resource allocation methods are proposed to address the problem of how flexibly allocate limited wireless resource to high bandwidth demanded realtime class with certain QoS guarantees in CDMA/TDD systems. In this method, A reserved access scheme is used for allocating the resource to realtime and non-realtime class respectively. We also propose a slot allocation algorithm for the CDMA/TDD system, which can prevent the performance degradation due to the interlink interference in each cell. Our framework is able to guarantee QoS continuity of realtime class and carry the maximum number of non-realtime subscriber. System performance of proposed method is evaluated by considering transmission delay, channel utilization and data loss, assuming a practical multi-cell environment and a multimedia service model. Our simulation results demonstrate the significant performance improvement.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.125-133
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• 2008

In this paper, we propose active queue management mechanism (Active-WRED) to guarantee quality of the high priority service class in multi-class traffic service environment. In congestion situation, this mechanism increases drop probability of low priority traffic and reduces the drop probability of the high priority traffic, therefore it can improve the quality of the high priority service. In order to analyze the performance of our mechanism we introduce the stochastic analysis of a discrete-time queueing systems for the performance evaluation of the Active Queue Management (AQM) based congestion control mechanism called Weighted Random Early Detection (WRED) using a two-state Markov-Modulated Bernoulli arrival process (MMBP-2) as the traffic source. A two-dimensional discrete-time Harkov chain is introduced to model the Active-WRED mechanism for two traffic classes (Guaranteed Service and Best Effort Service) where each dimension corresponds to a traffic class with its own parameters.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.717-724
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• 2005

In this paper, we Propose an efficient scheduler well suited for the next-generation wireless networks that can support multimedia traffic having various requirements. The scheduler is designed to provide each of multimedia classes with differentiated services. In particular, the scheduler is intended to maximize throughput and minimize packet loss ratio. To apply the scheduler, we suppose that the wireless network is based on TDD/CDMA system The scheduler assigns a packet in a dedicated uplink-slot to the user within a frame to operate scheduling of packets transmitted by the users belonging to the specific class in an efficient manner. Such a manner also enables the scheduler to meet different QoS requirements. The paper also includes performance comparison with other schemes and analysis of the proposed scheduling algorithm by using simulation. We also analyze the proposed scheme by using simulation. The simulation compares the proposed scheduling algerian with previously proposed schemes in terms of the performance.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.123-132
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• 2021

Malicious activities of Botnets are responsible for huge financial losses to Internet Service Providers, companies, governments and even home users. In this paper, we try to confirm the possibility of detecting botnet traffic by applying the deep learning model Convolutional Neural Network (CNN) using the CTU-13 botnet traffic dataset. In particular, we classify three classes, such as the C&C traffic between bots and C&C servers to detect C&C servers, traffic generated by bots other than C&C communication to detect bots, and normal traffic. Performance metrics were presented by accuracy, precision, recall, and F1 score on classifying both known and unknown botnet traffic. Moreover, we propose a stackable botnet detection system that can load modules for each botnet type considering scalability and operability on the real field.