• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.33-38
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• 2003

Most of the existing algorithms try to disseminate the multimedia contents of internet service provider (ISP), without taking into account characteristics and capacities of duplicated servers. However, they are less reliable without prior information on capacities of duplicated servers. In this paper we propose two algorithms, performance rating algorithm of hardware and capacity algorithm, inspired by the need of improving QoS of delivering multimedia contents without incurring long access delays when the capacities of duplicated servers are significantly different and clients locate in a fixed geographical domain Our simulation results show that they are better than HTTP response time algorithm when the multimedia contents are large and quite different from performances between duplicated servers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.99-110
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• 2010

Recently, network based DDoS attacks have been changed into application layer DDoS attacks which are targeted at the web services. Specially, an attacker makes zombie PCs generate small traffic and its traffic pattern has been similar to the normal user's pattern. So, existing HTTP PPS based Threshold cannot defend the DDoS attacks effectively. In this paper, we displayed all the GET Flooding attack types and propose three DDoS attack defense mechanisms which are simple and very powerful. Proposed mechanisms can defend all the existing GET Flooding DDoS attacks and be deployed in the real environment immediately with little resource consumption.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.1-9
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• 2004

User-Perceived application-level performance is a key to the adoption and success of CDMA 2000. To predict this performance in advance, a detailed end-to-end simulation model of a CDMA network was built to include application traffic characteristics, network architecture, network element details, and protocol features. We assess the user application performance when a Radio Access Network (RAN) and a Core Network (CN) adopt different transport architectures such as ATM and If. For voice Performance, we found that the vocoder bypass scenario shows 8% performance improvement over the others. For data packet performance, we found that HTTP v.1.1 shows better performance than that of HTTP v.1.0 due to the pipelining and TCP persistent connection. We also found that If transport technology is better solution for higher FER environment since the IP packet overhead is smaller than that of ATM for web browsing data traffic, while it shows opposite effect to small size voice packet in RAN architecture. Though simulation results we showed that the 3G-lX EV system gives much better packet delay performance than 3G-lX RTT, the main conclusion is that end-to-end application-level performance is affected by various elements and layers of the network and thus it must be considered in all phases of the technology evolution process.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.275-276
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• 2016

기존의 HTML의 경우 미디어 재생, 3D 그래픽 처리, 웹 소켓 통신 등을 위해서는 Silverlight나 Active-X와 같은 비 표준 플러그인을 설치해야만 구현할 수 있었다. 하지만, 차세대 웹 표준인 HTML5에서는 별도의 플러그인 설치 없이 자바스크립트의 신규 기능만으로 미디어 재생 등과 같은 동적인 기능을 구현할 수 있다. 이처럼 HTML5에서 자바스크립트 기능이 강화됨에 따라 이를 악용한 신종 사이버 공격의 위협이 증가 하고 있다. 기존의 악성 코드 공격과는 달리 사용자 단말에 어떠한 감염도 없이, 악성 스크립트를 삽입한 웹 페이지 접속만으로 악성 행위를 유발하기 때문에 기존의 보안기술로는 탐지에 한계가 존재한다. 이에 본 논문에서는 로컬 프록시를 활용하여, 사용자 단말에서 송/수신되는 HTTP 트래픽을 수집하고, 이를 분석하여, 악성 자바스크립트를 탐지 및 차단하고, 나아가서 난독화 된 악성 자바스크립트를 탐지하는 방법을 제안하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1235-1238
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• 2005

P2P(peer-to-peer) 웹 캐슁 모델은 서버 쪽에 집중되는 트래픽을 완화시킴으로써 전통적인 웹 캐슁 모델을 보완할 수 있다는 측면에서 최근에 활발히 연구되어 왔다. P2P 웹 캐슁은 클라이언트들의 로컬 캐쉬를 활용하여 부가적인 인프라의 추가없이 캐쉬 공간이 확대되는 효과를 얻을 수 있지만, 각 클라이언트들은 독립된 피어로서의 자율성(autonomy)을 가지므로 이러한 자율성의 제한을 최소화해야한다. 본 논문에서는 피어의 자율적인 동적 참여와 로컬 캐슁 전략을 보장하여 시스템의 실행 가능성(feasibility)을 높인 환경에서 효율적인 디렉토리 기반 P2P 웹 캐슁 시스템을 제안하였다. 제안하는 P2P 웹 캐슁 시스템은 동적인 P2P 네트워크 상에서의 오브젝트의 lifetime을 예상하여 이를 저장 공간 관리(storage management)에 적용하였다. 시스템의 성능 평가를 위하여 클라이언트의 http 요청 로그 데이터셋을 이용하여 트레이스 기반(trace-driven) 실험을 수행하고, 제안하는 시스템이 기존의 시스템에 비하여 주어진 동일한 환경에서 더 높은 정확성을 가짐을 확인하였다.

• Electronics and Telecommunications Trends
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• v.14 no.1 s.55
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• pp.24-35
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• 1999

90년도 들어 WWW의 등장과 함께 TCP/IP를 이용하는 인터넷의 폭발적인 사용증가로 인해 TCP/IP를 ATM 네트워크에서 사용하기 위한 연구가 필요하게 되었다. 현재 IP의 제한적인 기능 및 여러 가지 오버헤드로 인해 ATM 네트워크에서 IP를 효율적으로 운용하는데 많은 문제가 따르고 있다. 현재까지의 연구로는 ABR 또는 UBR 위에서 TCP/IP를 서비스하는 방안이 제시되고 있고, ABR을 TCP/IP의 전송수단으로 사용하는 경우 발생될 수 있는 문제점 및 스위치에서의 버퍼 요구량 등에 대한 연구가 진행되어 왔다. 본 연구에서는 HTTP 트래픽이 갖는 특성으로 인해 TCP/ABR이 가질 수 있는 문제점을 도출하고 해결책을 제시했다. 향후에 제시된 방법들의 성능은 시뮬레이션 및 큐잉 이론 등을 이용한 해석이 필요하다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.239-249
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• 2003

A lot many WWW sites are come into the world more and more as Web is considered as the unified Internet information tool. The location of each site or resource is usually specified by a physical URL, which is often too long to remember and tends to raise difficulty to show the aim of the site intuitively by seeing it. Since any person or organization can get his/her own domain name easily, it is more desirable to use a logical URL with the domain name which can be chosen more compact to remember and meaningful to represent the ultimate intention of the site. This paper presents an implementation of a URL forwarding server which forwards a URL to another, so that a WWW site can use a logical URL instead of a physical one. The server consists of a domain mapper which uses the redirection transaction of the HTTP protocol, and a name server based on the HIND. The paper shows how the interaction between the domain mapper and the name sever can make forwarding possible and describes its implementation in detail. Experimental results shows that the overhead incurred by URL forwarding is negligible compared to the typical delay of current Internet traffic condition.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.417-422
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• 2015

A service size of the IoT environment is determined by the number of sensors. The number of sensors increase means increases the amount of data generated by the IoT environment. There are studies to reliably operate a network for research and operational dynamic buffer for data when network congestion control congestion in the network environment. There are also studies of the stream data that has been processed in the connectionless network environment. In this study, we propose a sensor gateway for processing big data of the IoT environment. For this, review the RESTful for designing a sensor middleware, and apply the double-buffer algorithm to process the stream data efficiently. Finally, it generates a big data traffic using the MJpeg stream that is based on the HTTP protocol over TCP to evaluate the proposed system, with open source media player VLC using the image received and compare the throughput performance.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3088-3096
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• 1997

In this paper, we present WWW system over native ATM services. The use of native ATM services through ATM API can provide better performance and functionality than that of IP over ATM, LAN Emulation or Multiprotocol over ATM. Our WWW browser and server provide advanced WWW services based on enhanced performance and guaranteed QoS support by using native ATM service benefits. This paper describes and compares advantages and disadvantages of Native ATM Services and ATM Internet Services, and addresses ATM API standardization and development trend that are made by the ATNI Forum for the support of native ATM services, and then describes the architecture and operation of our WWW browser and server using ATM API. The system architecture is based on HTTP over ATM API capable of supporting guaranteed QoS over its connections. The system defines and uses new HTML attributes within hyperlinking HTML elements for the description of ATM QoS and traffic characteristics that are derived from UNI signaling 3.1 connection characteristics information elements. Our system uses WinSock 2 API as its ATM API.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.6
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• pp.414-423
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• 2014

The number and size of resource constituting the web page has been increasing steadily, and this circumstance leads to rapidly falling quality of web service in mobile network that offer relatively higher delay. Moreover, Improving the quality of a web services protocol is difficult to provide network function because the current network architecture has closed structure. In this paper, we suggest schemes to enhance web performance in mobile network, which are Check Coded DOM scheme and Functional JavaScript Transmission scheme, and then try to seek idea which can be provided suggested schemes as a network function using NFV(Network Function Virtualization). For the performance evaluation and analysis about the suggested schemes, we perform network simulation using SMPL library. We confirm that suggested schemes offer better performance in term of page loading time, the number of message and the amount of traffic in the network than HTTP Protocol.