• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.865-874
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• 2002

HTTP (HyperText Transfer Protocol) is a transfer protocol used by the World Wide Web distributed hypermedia system to retrieve the objects. Because HTTP is a connection oriented protocol, it uses TCP (Transmission control Protocol) as a transport layer. But it is known that HTTP interacts with TCP badly. it is discussed about factors affecting the performance or HTTP over TCP, the transaction time obtained by the per-transaction TCP connections for HTTP access and the TCP slow-start overheads, and the transaction time for T-TCP (Transaction TCP) which is one or methods improving the performance or HTTP over TCP. Average waiting time and average turnaround time are important parameters to satisfy QoS (Quality of Service) of end users. Formulas for calculating two parameters are derived. Such formulas can be used for the environment in which each TCP or T-TCP transaction time is same or different. Some experiments and computational experiences indicate that the proposed formulas are well acted, can be applied to the environment which the extension of bandwidth is necessary, and time characteristics of T-TCP are superior to that of TCP. Also, the load distribution method of web server based on the combination of bandwidths is discussed to reduce average waiting time and average turnaround time.

• 대한공업교육학회지
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• v.33 no.2
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• pp.248-258
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• 2008

Current Internet uses HTTP (Hyper Text Transfer Protocol) as an application layer protocol and TCP (Transmission Control Protocol) as a transport layer protocol to provide web service. SCTP (Stream Control Transmission Protocol) is a recently proposed transport protocol with very similar congestion control mechanisms as TCP, except the initial congestion window during the slow start phase. In this paper, we present a mathematical model of object transfer latency during the slow start phase for HTTP over SCTP and compare with the latency of HTTP over TCP. Validation of the model using experimental result shows that the mean object transfer latency for HTTP over SCTP during the slow start phase is less than that for HTTP over TCP by 11%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.4
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• pp.3-14
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• 2001

A Web server makes use of the HTTP(Hyper Text Transfer Protocol) to communicate with a client. The HTTP is a stateless protocol; the server does not maintain any state information for ongoing interactions with the client. Therefore, the HTTP inevitably requires additional overhead as repeating data key-in to user for continuing communications. This overhead in Web environment can be resolved by the cookie technologies. However, the cookie is usually unsecured due to the clear-text to transfer on the network and to store in the file. That is, information in the cookie is easy to exposure, copy, and even change. In this paper, we propose a secure cookie mechanism appropriate to Web environment, and then present a design and implement of secure Web system based on the scheme. The Web system can be used to any web environment. It also provides some security services, such as confidentiality, authentication, integrity.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.543-552
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• 2002

Wireless Session Protocol(WSP) which was updated and supplemented based on HyperText Transfer Protocol(HTTP) was designed by Wireless Application Protocol(WAP) forum regarding the characteristics of wireless environment. WSP improved the performance in wireless network, and introduced various facilities considering wireless environment. In this paper, we more improve the performance of WSP adding protocol message compression capability; we cail improved WSP protocol as WSP+. And, we analysis the performance of each protocol with WSP and WSP+ implementation. As a result of experiment, the capability which proposed in this paper reduced a response traffic about 45%. In $10^{-4}$ bit error rate, we also found the packet loss rate and time delay per transaction of WSP+ was improved over 40%. Finally, we found that the protocol message compression capability reduces message retransmission count in transaction layer and shorten the delay time per transaction by reducing a message size.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2109-2111
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• 2003

In this paper, It is studied to monitor the remote system status using HTTP(HyperText Transfer Protocol) object communication. This system is organized by three different part depending on functionality - server part, client part, controller part. The JAVA technology is used to composite the server part, the client part and C language is used for a controller.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.377-386
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• 2003

In this paper, we present an application layer protocol to support secure wireless Internet services, called Application Layer Security(ALS). The drawbacks of the two traditional approaches to secure wireless applications motivated the development of ALS. One is that in the conventional application-specific security protocol such as Secure HyperText Transfer Protocol(S-HTTP), security mechanism is included in the application itself. This gives a disadvantage that the security services are available only to that particular application. The other is that a separate protocol layer is inserted between the application and transport layers, as in the Secure Sockets Layer(SSL)/Transport Layer Security(TLS). In this case, all channel data are encrypted regardless of the specific application's requirements, resulting in much waste of network resources. To overcome these problems, ALS is proposed to be implemented on top of HTTP so that it is independent of the various transport layer protocols, and provides a common security interface with security applications so that it greatly improves the portability of security applications. In addition, since ALS takes advantages of well-known TLS mechanism, it eliminates the danger of malicious attack and provides applications with various security services such as authentication, confidentiality integrity and digital signature, and partial encryption. We conclude this paper with an example of applying ALS to the solution of end-to-end security in a present commercial wireless protocol stack, Wireless Application Protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.463-466
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• 1998

다양한 응용분야에서 사용되고 있는 웹은 최근 전자상거래 둥에서의 이용에 대한 기대가 한층 고조되고 있다. 그러나 이러한 웹은 전자상거래 행위에서 특히 중요한 부인봉쇄 서비스가 제공되고 있지 않으며 64비트 이하의 비도로 기밀성 서비스를 제공하고 있다. 이 논문에서는 WWW의 보안 요구사항 및 이를 위한 WWW 프로토콜로 IETF(Internet Engieering Task force)에서 제안한 S-HTTP(Secure HTTP, Secure HyperText Transfer Protocol)를 기반으로 하는 안전한 WWW시스템 개발, Apache-Shttp를 위한 기능 설계, 개발 환경 및 개발된 시스템의 시연을 기술한다.

• Journal of the Korea Safety Management & Science
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• v.4 no.1
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• pp.27-36
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• 2002

This paper describes "the remote automatic diagnosis and repair system which automatically reads the problems such as "out of order" occurred on equipment at customer's equipment from a remote computer center using HTTP(hyper text transfer protocol). It shows the scheme of the network configurations and features of the system. In addition, a way to implement the overall system, the specific functions of unit, and the operational specifications between the center's computer and customer's computer are also presented.also presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.107-113
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• 2005

In this paper, Web server is built up using PXA255, 32bit RISC processor with porting Embedded Linux and GoAhead HTTP(Hyper Text Transfer Protocol) web server, and the system which can monitor and control the environment and condition for AICC(Automatic Intelligent Cruise Control) is realized For sensing the operation condition and change of vehicle the desired data is derived by interfacing ECU(Electric Control Unit) and Embedded system and the rpm of engine is controlled by step motor connected to throttle valve.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.43-53
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• 2008

Hyper text transfer protocol (HTTP) over transmission control protocol (TCP) is currently used to transfer objects in the Internet. Stream control transmission protocol (SCTP), an alternative to TCP, which allows for independent delivery among streams, and can thus reduce the mean response delay of web object. We present an analytical model to find the mean response delay for HTTP over SCTP, therefore, estimate the effectiveness of SCTP over TCP. Typical TCP delay models assume the wired environment. On the contrary, the proposed model in this paper assumes the multiple packet losses and wireless environment where fast retransmission is not possible due to small window. The estimated mean response time can be used the benchmark to meet quality of service (QoS) at end-user. We validate the accuracy of our model using experiments. It is shown that the differences between the results from model and those from experimental are very small below 6 % on average. We also find that the mean response delay for HTTP over SCTP is less than that for HTTP over TCP.