In this paper, different methods of integrating heterogeneous network information systems into the Web are observed by comparing a cliented Java CGI model with a server-oriented CGI model. In addition, a load balanced(LB, for short) CGI model is proposed, which combines two models and decides its course of action depending on the load state of the web server, and compared with the other two models. Performance evaluation models for three models are also presented. The results of computer simulations indicate that the LB CGI model performs consistently well irrespective of system load or server performance.

Because of the rapid growth of the mobile communication, the need for the mobile internet access has grown up as well. since the current mobile communication network, however, is optimized for a voice communication system, which exclusively occupies a channel for a given time, it is not suitable for variable rate packet data. In order to support the mobile internet access, it is essential do design a reasonable packet switching network which supports the mobility. Since mobile packet network has longer latency, high speed switching and QoS are required to meet the user's requirements. In this paper, we suggest an resonable way to construct a network and its operation procedures utilizing GPRS(General Packet Radio Service) network and MPLS(Multi Protocol Label Switching) to provide a high speed switching and QoS mobile internet access. GPRS is used as a network which supports the mobility and MPLS guarantees the QoS and high speed IP protocol transmission based on the ATM switching technology.

Recently the number of Internet users have been drastically increased with the introduction of WWW browsers, which requires accommodation study of TCP/IP on ATM networks. There are a number of problems in operating IP-over-ATM efficiently because of limited functions and overhead of IP. According to recent research, the alternatives to TCP/IP efficiently because of limited functions and overhead of IP. According to recent research, the alternatives to TCP/IP over ABR or UBR have been suggested, and the required capacity of switch buffer and problems in TCP/IP over ABR have been researched. In this paper, we address problems caused by the features of HTTP traffic and suggest a solution for TCP over ABR. The performance of the methods suggested in this paper is verified through simulation under limited conditions.

Currently in the Web(World Wide Web) environment, HTML(Hyper Text Markup Language) is used for information representation and exchange. But it is thought that HTML has some constraints in information representation of various kinds because of its limited tag set. And it is considered that combining the HTML, which is used for static information representation in Web environment, with Scripting language, which is usually used for multimedia information representation in a synchronized framework, can be very useful. Consequently we show the general trend of the Scripting language in Web environment and show the possibility of HTML and Scripting language amalgamation for Web service improvement.

Currently, car information service systems are lack of providing retrieval service, because most of them aim for buying and selling. Thus, in this paper, we design and implement CISS(Car Information Service System on Internet) to provide efficient retrieval for car information. In CISS, we collect information of cars on Internet and construct the lattice structure for efficient retrieval. And we provide retrieval convenience by implementing of Car Browser that permits gradual refinement of the index term by browsing through lattice graph and that permits keyword-based retrieval.

At recent, the Internet is evolving into the directions which is capable of incorporating stream-type services such as voice and video services due to the remarkable growth of WWW service and the development of new multimedia application services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS-based routing algorithm in order to allow flexible routing by the Internet user's QoS demand and to be applied into wide area networks. In this paper, we presented new routing algorithms for next generation Internet services and made performance evaluations. The proposed algorithms allow the routing by the user's QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of next Generation Internet Services.

There are many problems to be satisfied the various commercial demand in the present VRML node, and the VRML-based system by the contact with other technology is burdened with the direct participation of developer related with it. In this study, remote control and monitoring system using EAI(External Authoring Interface) is reposed to overcome the limit of VRML. In other words, This study is about mechanism of interaction between control and monitoring subject in real world and object in virtual world mapped with it. Object oriented method by one to one mapping of the Java class which have VRML virtual world and the object control is proposed. Introduction method of video monitoring through method of image synthesis and the integrated development environment is described. Finally automobile-gate control system based on the development method of Internet virtual reality-based system which is proposed in this study is described.

In this paper, we present a new mechanism applying more strict priority than RIO mechanism proposed as a drop precedence policy of AF classes in differentiated services. In this mechanism, applying strict priority to drop precedence policy, we get better performance on priority level. Simulation results indicate that the proposed mechanism may provide more efficient and more strict priority transmissions as compared to RIO regardless of traffic load.

As the proliferation of multimedia traffic over High-speed Internet increases, ATM network will be vital to adopt as backbone network over various parts of Internet. In this paper, we investigate the performance of TCP/IP traffic flow over ABR and UBR of ATM service to study for the high throughput and good fairness by simulation technique. Although TCP is run in the transport layer, it is controlled by several methods, e.g, EPD, PPD, RED, EFCI, ER etc, in ATM layer when TCP uses the ABR/UBR service. Therefore, if one cell is discarded in ATM layer, a packet of TCp will be laost. And, also, along with the increasing of the number of VC among switches, the throughput and fairness will be degraded. In order to improve these degradations, we propose the effective parameter control operations of EFCI and ER on ABR service, and also suggest the buffer management methods on UBR service. Finally, through the simulation results, the improved throughput and fairness are shown.

To promote the inclusion of end-to-end congestion control in the design of future protocols using best-effort traffic, we propose a router mechanism, Extended FRED(ex-FRED). In this paper, we catagorize the TCP controlled traffics into robust and fragile traffic and discuss several unfairness conditions between them caused by the diverse applications. For example, fragile traffic from bursty application cannot use its fair share due to their slow adaptation. Ex-FRED modifies the FRED(Fair Random Early Drop), which can show wrong information due to the narrow view of actual buffer. Therefore, Ex-FRED uses per-flow accounting in larger virtual buffer to impose an each flow a loss rate that depends on the virtual buffer use of a flow. The simulation results show that Ex-FRED uses fair share and has good throughput.

This paper proposes a security platform, called SCAP(Security platform for CORBA based APplication), to cope with potential threats in a distributed object system. SCAP supports CORBA security specification announced by OMG. SCAP is comprised of four functional blocks, which co-work with ORB to provide security services: Authentication Block, Association Block, Access Control Block, and Security Information Management Block. It is designed to support Common Secure Interoperability Functionality Level 2, which is useful for large-scale intra-, or inter-network based applications. Actual security services, which are dependent on supporting security technology, will be provided as external security service for replace ability. Implementation issues such as how to simulate an interceptor mechanism using a commercial ORB product without source code, and how to extend Current object required for security services are also described. At the end of the paper, the SCAP applied to the web environment is described to show its practical utilization.

E-mail system is the most important service that enterprises and normal users in internet use. However, because a data security is not satisfied yet, and E-mail system with security service is essential. In this paper, We implemented the E-mail system with Certification of Delivery that was not provided in prior mail system with basic security services and can prove that sender's document is properly sent to the intended receipt. And an implementation of the system used Java Cryptography API.

One of the most important prerequisites for a successful software process is the collaboration and software requirements negotiation of all stakeholders in the software development process. Remote users using computer networks can negotiate software requirements by computer supported system, and can share their informations. The goal of software requirements negotiation system is an integration of all win conditions and an agreement after resolution of conflicts. The existing systems need an exclusive system and must be dependent on specific platform and network. Users must have the knowledge of all stakeholder's status and use homogeneous collaborating applications. This paper presents the Web-based software requirements negotiation system for the purpose of resolution of the existing systems' problems. The Web-based software requirements negotiation system can be driven by WinWin Spiral model, and it is based on hybrid execution method. The proposed system is validated and tested on heterogeneous environments.

Seamless end-to-end Internet Quality of Service (QoS) management is very only because Internet Management is not well understood and practiced in the real world but because the nature of the Internet is hard to predict and manage. Secure transmission, transport reliability, ability to differentiate service qualities, QoS-based intelligent routing, QoS monitoring, and customer-oriented service management are essential technical huddles to be coped with. Despite of these difficulties, the Internet becomes the platform of choice for the next generation applications and services. without a solid management solution, it is not easy to deploy high quality commercial services. In this paper, we propose an architecture of seamless end-to-end Internet QoS Management System and describe the design principles and system components of our developing prototype system.

In this paper, we explore two ways to improve the bandwidth assurance performance of Assured Service(AS). It is well known that AS fails to meet the bandwidth assurance target for large-profile TCP flows competing with many small-profile flows. This flows after the back-offs induced by packet drops. Thus currently proposed solution to this problem naturally focus on modifying TCP's behavior to counter the unfairness in the TCP dynamics. Unfortunately, these proposals lack practicability in terms of the required changes in the incumbent Internet infrastructure. Admitting this difficulty, we instead look to not yet deployed Diff-Serv mechanisms for practical solutions. In particular, we investigate the role of RIO, RED with IN(in-profile) and OUT(out-profile), queue management scheme in the assurance failure for As. Specifically, we identify the inadequacy of RIO that aggravates the bandwidth assurance failure. Then we alleviates the bandwidth assurance failure problem by separately controlling the out-of-profile packet queue length. Through extensive simulations we demonstrate that RI+O extends the regime where AS consistently provides the bandwidth assurance.

TCP protocol is originally designed for the wired network in which the packet loss in mostly caused the network congestion, and thus the performance of protocol can be decreased in mobile Internet environment due to the comparatively high error rate of wireless link. This paper analyzes the influence of retransmission interference that is a major factor to the TCP performance decrease. We first build a model in order to simulate the mobile Internet environment that includes the wireless network, and then we implement a program using PARSEC simulation language and finally executed the program. Based on the simulation results, we suggest a method that reduce the effect of the retransmission interference.

Supporting object group on distributed object system give merits such as load balancing, fault tolerance and high availability. In this paper, we describe a CORBA ORB that has been designed to support object group based on active replication. The ORB supports the operational model in which it uses the IIOP for communication between client and server and total ordered multicast protocol for consistency control among group members. And through extension of ORB, it provides functions required for support of object group. Since it provides transparency of object replication, the ORB is interoperable with the existing CORBA products. It make possible for existing server application to be easily extended to application supporting object group as adding interface functions which should be used for building applications is minimized. A prototype is implemented, and performance of the replicated object group is tested and compared with a single object invocation.

Modeling for the Internet resource is important to use of limited resource efficiently. Also, the modeling could guide how we can approach the Internet problems. The many studies of price mechanism to internalize the externality, to decrease the externality from congestion, and to use the Internet resource efficiently, are widely going on. The represent styles for Internet pricing are usage-based pricing(UBP) and flat-rat pricing(FRP) and the FRP could prefers for the beginning stage of Internet introduce. The purpose of this study is to examine the efficiency of Internet pricing mechanism based on flat-rate pricing, both consumer and producer side.

Electric commerce system based on distributed mobile on object such as mobile agents need both precise identification and secure authentication scheme on remotemobile entities. In this paper, existing discrete logarithm based Schnorr like entity authentication schemes are improved by the analysis of performance and security on the bi-directional interactive proofs. And ElGamal like schemes are also proposed. Then, there are enhanced with oblivious transfer based mono-directional authentication schemes based on trusted third party for applying to the mobile agent based computing systems. Therefore, proposed schemes provide compatible performance and safety on mobile entity authentication process.

ATM technology, which acts as a representative high-speed bandwidth technology, plays an important role in Internet environment. ATM network, supporting QoS(Quality of Service) and various traffic characters in high speed, configures many VPC(Virtual Path Connection)/VCC(Virtual Channel Connection). It is important to guarantee the QoS of each connection and it is necessary for the network manager to search element affecting the QoS of VPC/VCC and to control ATM network correctly. In the paper, the management information of VPC/VCC, that ATM network manager Using the fault notification for ATM switch, we can manage the configuration, fault and performance of ATM network. Thus, we extracted the configuration, fault and performance monitoring item from the ATM-MIB and SNMP M4 Network Element View MIB. And we designed the ATM network configuration, fault and performance management system based on the extracted item.

Important network application services have been rapidly increased along with the growth of the Internet. So, it is desirable for such applications to serve transparently, continuously and safely even if the network is temporally disconnected or certain hosts running those services are crashed down. To satisfy such requirementes, many group communication systems have been developed; but, those systems restrict its range within a single LAN or directly interconnected LAN environments since the communication through the Internet is too slow and too unreliable to support group communication. As of now, it is expected the Internet is going to e sufficiently fast and reliable in the near communication system, named FACE(Java Advanced Communication Environment), supporting Extended Virtual which is a basic communication layer, RPGS(Reliable Process Group Service) which manages application process groups, and JACE API for developing Java application services and clients programs. In addition, an experimental replicated object space is developed as an application of the JACE system.

To achieve high-speed communication and to improve QoS characteristics, ATM is now being used as underlying transfer mechanism of Internet protocols, or TCP/IP. When TCP uses the ABR service in ATM networks, the ABR service control is important to improve the performance of TCP/IP traffic as long as there is no interaction between ABR rate control and TCP flow control. In such environment, the interoperability of EFCI and ER switches becomes unavoidable in order to more effectively control ABR traffic in ATM network. In this paper, we use the model of mixed EFCI-ER environment and discuss the performance issues, e.g., the fairness of bandwidth allocation, drop rate, throughput by using various ER switch algorithms. Among various ERSwitch algorithms, we present one algorithm that have a less network topology and allocate the fair share of VC bandwidth by simulation results.

Information filtering for internet search, in which new information retrieval environment is given, is different from traditional methods such as bibliography information filtering, news-group and E-mail filtering. Therefore, we cannot expect high performance from the traditional information filtering models when they are applied to the new environment. To solve this problem, we inspect the characteristics of the new filtering environment, and propose a semantic-based filtering model which includes a new filtering method using WordNet. For extracting keywords from documents, this model uses the SDCC(Semantic Distance for Common Category) algorithm instead of the TF/IDF method usually used by traditional methods. The world sense ambiguation problem, which is one of causes dropping efficiency of internet search, is solved by this method. The semantic-based filtering model can filter web pages selectively with considering a user level and we show in this paper that it is more convenient for users to search information in internet by the proposed method than by traditional filtering methods.

Autonomous Intrusion Analysis Agent(AIAA) is Incident Response Team staff's tool that scans, analyses, reports and alerts the traces of intrusion based on system logs and intruder's backdoors inside compromised system by IR staff after security incident is reported to the IR team. AIAA is intelligent to recognize to check out who is intruder from all the user accounts and to report the suspected candidates to the master control system in IR team. IR staff who controls AIAA with master system can pick up an intruder from the candidates reported by AIAA agent and review all related summary reports and details including source host's mane, finger information, all illegal behavior and so on. AIAA is moved to compromised system by the staff to investigate the signature of intrusion along the trace of victim hosts and it is also operated in secret mode to detect the further intrusion. AIAA is alive in all victim systems until the incident is closed and IR staff can control AIAA operation and dialogue with AIAA agent in Web interface.

Since most of CSCW(Computer-Supported Cooperative Work) systems have been developed for particular computing platforms, they are usable only within the specific organizations supporting those particular platforms. Recently, according to the rapid growth and continuing success of the World-Wide Web(WWW or Web) which offers a globally accessible platform-independent infrastructure, many CSCW systems has been constructed and is being developed on the basis of the Web. As one of such CSCW systems, in this paper, we describe the design and implementation of the CoSpace system. The CoSpace system provides shared workspaces, which enable members of a work group easily share information for collaborative work through their Web Browsers. The shared workspaces support information sharing and management between users, and also support event monitoring and synchronization between collaborative works.