• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4A
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• pp.412-420
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• 2006

With the appearance of various types of traffic services in communication networks, a study on QoS(Quality of Service) packet scheduling mechanisms which can support differentiated service to each traffic service becomes very important. To meet this requirement, IEEE 802.11 Working Group established the IEEE 802.11e MAC protocol which categorizes every traffic services into 4 access categories(AC) and provides the differentiated service to each AC. In addition, the physical layer of IEEE 802.11a/g standards provide up to 54 Mbps transmission rate per one wireless LAN terminal. However, since the radio resource is hardly limited in wireless channel, it is necessary to find an efficient packet scheduling scheme to maximize the transmission efficiency. Therefore, in this paper, we proposed a new packet scheduling scheme that can enhance the total throughput by setting different contention windows(CW) of CSMA-CA channel access scheme to each wireless LAN terminal according its current channel states. Numerical results derived from using NS-2 network simulator have shown that our proposed packet scheduling scheme can enhance the performance of IEEE 802.11e more and more.

• The Journal of Society for e-Business Studies
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• v.7 no.3
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• pp.203-218
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• 2002

According as development of networks and increasing on Internet service, For the performance increase of K4 Firewall require that hardware be installed of 2 CPU or 4 CPU instead of 1 CPU. Output of performance test among 1CPU, 2CPU, and 4CPU of K4 Firewall system has not any efficient about increasing multiple CPUs. K4 Firewall put performance on setting on demon of packet filtering rules and Network Address Translate and Authentication and Proxy services. Performance results that setting after security rules are less 2％ Packet Filtering, 8％-11％ NAT, 18％-20％ Proxy and Authentication services than setting before security rules on K4 Firewall System. NAT and Proxy service have decrease of performance. This performance result comes in useful for research and development on K4 Firewall System.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.7-12
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• 2006

In this paper we proposed a real-time remote monitoring system for interoperability between local area and wide area for wireless data communication. In local area, we used a miniaturized low-power wireless module and in wide area used CDMA Cellular System's Packet Data Service. The measurement results can be spread via Internet access in real-time

• Convergence Security Journal
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• v.12 no.3
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• pp.85-92
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• 2012

Today, the typical web hacking attacks are cross-site scripting(XSS) attacks, injection vulnerabilities, malicious file execution and insecure direct object reference included. Web hacking security systems, access control solutions, access only to the web service and flow inside but do not control the packet. So you have been illegally modified to pass the packet even if the packet is considered as a unnormal packet. The defense system is to fail to appropriate controls. Therefore, in order to ensure a successful web services diagnostic system development is necessary. Web application diagnostic system is real and urgent need and alternative. The diagnostic system development process mu st be carried out step of established diagnostic systems, diagnostic scoping web system vulnerabilities, web application, analysis, security vulnerability assessment and selecting items. And diagnostic system as required by the web system environment using tools, programming languages, interfaces, parameters must be set.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1783-1791
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• 2010

Mobile WiMAX system provides broadband wireless access with a variety of services such as voice, video and data communications and providing QoS for each of these services become an important issue. In Mobile WiMAX system, it is important to allocate resources appropriately in order to support the efficient utilization of resources among various real-time and non real-time services. Although many packet scheduling schemes for real-time services in OFDMA system have been proposed, it need to be modified to apply to Mobile WiMAX system. Since Mobile WiMAX supports five types of service classes, QoS constraints of each class should be taken into consideration. In this paper, we propose an efficient packet scheduling scheme to support various services by considering the QoS constraints of each class.

• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1767-1777
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• 2010

In digital TV broadcasting, such as terrestrial, cable, satellite, and IPTV, the head-end of digital TV broadcasting has a more complicated transmission structure than that of analog TV broadcasting. Furthermore, digital TV broadcasting has a feature that supports multiplex models, such as Multiple Program Transport Stream (MPTS). Therefore, the purpose of our work was to design and examine a more efficient new system of emergency alert message transmission to support the digital TV broadcasting environments. Digital TV broadcasting is the IP generation or RF transmission of 8-VSB, QAM, and QPSK modulated through a multiplexer or re-multiplexer multiplexed stream as a MPEG-2 Transport Stream after content encoding. The new system proposed in this paper transmits an emergency alert message without scrambling after replacing the PID and payload of the -packet with the message prototype in the TS stream from the multiplexer. If we need to transmit an emergency alert message under digital TV broadcasting services, then the receiver first checks the PID of each packet in the TS stream for the emergency alert message. Next, if a packet is determined to be an emergency alert message, then the set-top box displays the message on the TV screen using its function of On Screen Display, or the PC based software displays the message on the monitor screen using its function of overlay with user interface if the packet is found to be an emergency alert message. We have designed an emergency alert message protocol and a system model. By experiments and analysis of the system, we concluded that the system achieved efficiency and the ability to send and receive emergency alert messages using the system under different digital TV broadcasting service environments.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.469-481
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• 2004

In this paper, we investigate the mean queue length and the mean packet delay of a dynamic bandwidth allocation(DBA) scheme in an Ethernet passive optical network(EPON). We focus on the interleaved polling system with a gated service discipline. We assume that input packets arrive at an optical network unit(ONU) according to Poisson process. We use a continuous time queueing model in order to find the queue length distribution of the gated interleaved polling system with the first stage input queue and the second stage transmission queue. We give some numerical results to investigate the mean queue lengths and mean packet delays for the symmetric polling system with statistically identical stations.

• IE interfaces
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• v.13 no.4
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• pp.709-716
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• 2000

In this paper, We analyze a capacity dimensioning and performance of the access line to the X.25 packet network when the AO/DI internet service is connected via D-channel. We show the forecasting methodology of the traffic demand of the D-channel internet services when the TDX-1OA switching system accommodates the target number of subscriber. Based on the traffic demand forecast, the required capacity of the access line is suggested to prevent bottleneck problem in the access line to the X.25 packet network.

• ETRI Journal
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• v.27 no.6
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• pp.777-787
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• 2005

In this paper, we propose an urgency- and efficiency-based wireless packet scheduling (UEPS) algorithm that is able to schedule real-time (RT) and non-real-time (NRT) traffics at the same time while supporting multiple users simultaneously at any given scheduling time instant. The UEPS algorithm is designed to support wireless downlink packet scheduling in an orthogonal frequency division multiple access (OFDMA) system, which is a strong candidate as a wireless access method for the next generation of wireless communications. The UEPS algorithm uses the time-utility function as a scheduling urgency factor and the relative status of the current channel to the average channel status as an efficiency indicator of radio resource usage. The design goal of the UEPS algorithm is to maximize throughput of NRT traffics while satisfying quality-of-service (QoS) requirements of RT traffics. The simulation study shows that the UEPS algorithm is able to give better throughput performance than existing wireless packet scheduling algorithms such as proportional fair (PF) and modified-largest weighted delay first (M-LWDF), while satisfying the QoS requirements of RT traffics such as average delay and packet loss rate under various traffic loads.

• Journal of Service Research and Studies
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• v.5 no.1
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• pp.57-70
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• 2015

This paper develop curnel based high speed packet filtering imbedded gateway and firewall using cloud database. This study develop equipment include of predict function through bigdata analysis using cloud system. This equipment include intrusion prevention for network attack, and include system security function of L7 switch based contents. This study can improve security level of little company and general family. This study can pioneer a new market. This study can develop high perfomance switch and replacement of existing security equipment. This study proposed new next generation algorithm for constuction of high performance system from low specifications.