• IE interfaces
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• v.16 no.spc
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• pp.76-81
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• 2003

BPMS (Business Process Management Systems) is aninformation system that systematically supports designing, administrating, and improving the business processes. It can execute the business processes by assigning tasks to human or computer agents according to the predefined definitions of the processes. In this research we developed a task assignment algorithm that can maximize overall process efficiency under the limitation of agents' capacity. Since BPMS manipulates the formal and predictable business processes, we can analyze the processes using queuing theory to achieve overall process efficiency. We first transform the business processes into queuing network model in which the agents are considered as servers. After that, workloads of agents are calculated as server utilization and we can determine the task assignment policy by balancing the workloads. This will make the workloads of all agents be minimized, and the overall process efficiency is achieved in this way. Another application of the results can be capacity planning of agents in advance and business process optimization in reengineering context. We performed the simulation analysis to validate the results and also show the effectiveness of the algorithm by comparing with well known dispatching policies.

• ETRI Journal
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• v.25 no.1
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• pp.34-40
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• 2003

This paper considers a TMN-based management system for the management of public ATM switching networks using a four-level hierarchical structure consisting of one network management system, several element management systems, and several agent-ATM switch pairs. Using Jackson's queuing model, we analyze the effects of one TMN command on the performance of the component ATM switch in processing local calls. The TMN command considered is the permanent virtual call connection. We analyze four performance measures of ATM switches- utilization, mean queue length and mean waiting time for the processor directly interfacing with the subscriber lines and trunks, and the call setup delay of the ATM switch- and compare the results with those from Jackson's queuing model.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.357-365
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• 2009

To effectively exploit the underlying network bandwidth while maximizing user perceivable QoS, mandatory to make proper estimation on packet loss and queuing delay of the underling network. This issue is further emphasized in wireless network environment where network bandwidth is scarce resource. In this work, we focus our effort on developing performance model for wireless network. We collect packet trace from actually wireless network environment. We find that packet count process and bandwidth process in wireless environment exhibits long range property. We extract key performance parameters of the underlying network traffic. We develop an analytical model for buffer overflow probability and waiting time. We obtain the tail probability of the queueing system using Fractional Brown Motion (FBM). We represent average queuing delay from queue length model. Through our study based upon empirical data, it is found that our performance model well represent the physical characteristics of the IEEE 802.11b network traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.684-690
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• 2014

In this work we investigate the benefit of multicast in the delivery of video data over the mobile MBMS network. In order to quantify the benefit in a practical aspect, this work proposes an analytic framework that employs a combined statistical and queuing model, where a queuing model represents the behavior of user's access to the video service and the statistical model captures the popularity of the video contents, via which we draw out a more realistic intuition for the expected benefit from multicast. Finally, we present results of numerical experiment that illustrates the validity of the proposed work.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.107-114
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• 2011

Today the company adopts to use information management method at the network base such as internet, intranet and so on for the speed of business. Therefore the security of information asset protection and continuity of business within company in relation to this is directly connected to the credibility of the company. This paper secures continuity to the certified users using queuing model for the business interruption issue caused by DDoS attack which is faced seriously today. To do this I have reflected overloaded traffic improvement process to the queuing model through the analysis of related traffic information and packet when there occurs DDoS attack with worm/virus. And through experiment I compared and analyzed traffic loading improvement for general network equipment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.2
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• pp.63-81
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• 2008

WiMAX has been introduced as a competitive alternative for metropolitan broadband wireless access technologies. It is connection oriented and it can provide very high data rates, large service coverage, and flexible quality of services (QoS). Due to the large number of connections and flexible QoS supported by WiMAX, the uplink access in WiMAX networks is very challenging since the medium access control (MAC) protocol must efficiently manage the bandwidth and related channel allocations. In this paper, we propose and investigate a cost-effective WiMAX bandwidth management scheme, named the WiMAX partial sharing scheme (WPSS), in order to provide good QoS while achieving better bandwidth utilization and network throughput. The proposed bandwidth management scheme is compared with a simple but inefficient scheme, named the WiMAX complete sharing scheme (WCPS). A maximum entropy (ME) based analytical model (MEAM) is proposed for the performance evaluation of the two bandwidth management schemes. The reason for using MEAM for the performance evaluation is that MEAM can efficiently model a large-scale system in which the number of stations or connections is generally very high, while the traditional simulation and analytical (e.g., Markov models) approaches cannot perform well due to the high computation complexity. We model the bandwidth management scheme as a queuing network model (QNM) that consists of interacting multiclass queues for different service classes. Closed form expressions for the state and blocking probability distributions are derived for those schemes. Simulation results verify the MEAM numerical results and show that WPSS can significantly improve the network’s performance compared to WCPS.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.169-171
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• 2002

Ethernet PON(Passive Optical Network)은 지금까지 연구되고 있는 가입자 망 가운데 인터넷 트래픽에 가장 적합한 모델이다. 본 논문에서는 Ethernet PON의 성능분석을 위해서 OPNET을 이용하여 Ethernet PON 시뮬레이션 모델을 설계 및 구현한다 또한, 이 모델에 대한 End to end Ethernet delay, Queuing delay, Throughput과 Utilization 분석을 통해서 하나의 OLT(Optical Line Termination)가 수용 할 수 있는 최적의 ONU(Optical Network Unit) 개수를 산정하고 Ethernet PON을 설치할 때 망의 효율을 극대화하는 방안을 제안한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.395-396
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• 2014

최근 급증하는 교통 혼잡으로 인해 시간적/물리적 손실이 크게 발생하고 있다. 이러한 교통난 해소는 시설투자만으로는 근본적인 해결책이 될 수 없다는 판단 하에 지난 수년간 보다 정확한 교통량을 예측하기 위해 다양한 교통량 예측 모델들이 개발되어왔다. 그러나 기존 모델들은 회기분석을 통해 과거 교통량을 분석하고 과거의 교통패턴이 미래에 지속적으로 연장된다는 가정 하에 연구되었기 때문에 실시간으로 급변하는 불규칙한 교통 패턴에 대한 예측의 신뢰성을 떨어트린다. 이를 위해 본 논문에서는 큐잉 네트워크 모델 기반의 교통량 예측 모델을 설계 하고 이를 바탕으로 안드로이드 기반의 애플리케이션을 구현하였다.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.402-405
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• 2003

본 논문은 인터넷에서 실시간 서비스를 효과적으로 지원하면서도 망의 확장성을 제공하는 방법을 제안하였다. 이를 위해 코어노드에서 각 플로우의 상태 정보를 관리하지 않는 SCORE (Scalable CORE) 네트워크 모델 [1]과 종단간 딜레이 보장이 우수한 QoS (Qualify of Service) 스케줄링 방법중 하나인 WF²Q+ (Worst-case Fair weight Fair Queuing+) [2]에 대해서 기술하고 구현하였다. 이러한 개념을 바탕으로 새로운 망의 구조를 제안하였으며 시뮬레이션을 통한 성능분석을 수행하였다.

• International Journal of Computer Science & Network Security
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• v.23 no.4
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• pp.95-102
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• 2023

The emergence of Internet of Things (IoT) into our daily lives has grown rapidly. It's been integrated to our homes, cars, and cities, increasing the intelligence of devices involved in communications. Enormous amount of data is exchanged over smart devices through the internet, which raises security concerns in regards of privacy evasion. This paper is focused on the forensics and intrusion detection on one of the most common protocols in IoT environments, especially smart home environments, which is the Message Queuing Telemetry Transport (MQTT) protocol. The paper covers general IoT infrastructure, MQTT protocol and attacks conducted on it, and multiple network forensics frameworks in smart homes. Furthermore, a machine learning model is developed and tested to detect several types of attacks in an IoT network. A forensics tool (MQTTracker) is proposed to contribute to the investigation of MQTT protocol in order to provide a safer technological future in the warmth of people's homes. The MQTT-IOT-IDS2020 dataset is used to train the machine learning model. In addition, different attack detection algorithms are compared to ensure the suitable algorithm is chosen to perform accurate classification of attacks within MQTT traffic.