• Journal of the Korean Operations Research and Management Science Society
• /
• v.30 no.2
• /
• pp.131-142
• /
• 2005

This paper proposes queueing models for a Web server system which is composed of an infinite-buffer main server and finite-buffer auxiliary server(s). The system is modeled by the level-dependent quasi-birth- death (QBD) process. Utilizing the special structure of the QBD, we convert the infinite level-dependent QBD into a finite level-independent QBD and compute the state probabilities. We then explore the operational characteristics of the proposed web-server models and draw some useful conclusions.

• Journal of the military operations research society of Korea
• /
• v.23 no.2
• /
• pp.25-44
• /
• 1997

Internet users been rapidly increased due to the convenient GUI environment. Current Web-based HTTP/CGI client/server architecture has several problems such as the CGI bottleneck, no maintaince of state, and no load balancing. However, with Java and CORBA technologies called“Object Web technology”, we can solve them because Java is not only a mobile code but also a platform-independent code, and CORBA has ability to build distributed object and language-independent object model. The goal of “Object Web technology”is to create multivendor, multiOS, multilanguage“legoware”using objects. This paper implement“Book Search System”which is Web-based client/server architecture using distributed objects. Environments of this implementation are Hangul Windows NT(included IIS) server, Hangul Windows 95 client, Visigenic's VisiBroker for Java 1.2 which is a product of CORBA 2.0, HTTP protocol on TCP-IP-based, Sybase SQL Anywhere 5.0 database server, and the interface between application server and database is JDBC-ODBC bridge middleware.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.5
• /
• pp.1002-1011
• /
• 2005

In this paper. we design and implement a bi-directional broadcasting system, so called return channel server, to allow users to participate in a broadcasting program by using a hi-directional interaction channel. To provide user participation in a program and reflect the user's opinions or responses in real time, the return channel server can be viewed as consisting of four major functional modules: a control module, network interface module, DBMS module, and real-time content authoring module. To construct a return channel server that has a service independent architecture, we designed a return channel server to include the hierarchical structure. The presented return channel server consists of two parts: an RCSAE(return channel server application environment) and RCSA(return channel server application). An RCSA is composed of an execution code and a parameter for executing the execution code. RCSA defines the procedures for providing a specific broadcasting program using the return channel server. On the other hand, an RCSAE provides the environment for the execution of RCSAS. By adopting RCSAE and RCSA, we construct the return channel server that has a service-independent architecture which are shown by the test.

• Journal of Digital Convergence
• /
• v.17 no.2
• /
• pp.155-161
• /
• 2019

Electroencephalography (EEG), a representative method of identifying temporal and spatial changes in brain activity, is a voluntary electrical activity measurable in the human scalp. Various interface technologies have been provided to control EEG activity, and it is possible to operate a machine such as a wheelchair or a robot through brainwaves. The characteristics of EEG data are collected in various types of channels in real time, and a server system for analyzing them is required to have an independent and lightweight system for the platform. In these days, the Spring platform is used as a large business server as an independent, lightweight server system. In this paper, we propose an EEG analysis system using the Spring server system. Using the proposed system, the reliability of EEG control can be enhanced, and analysis and control interface expansion can be provided in various aspects such as game and medical areas.

• Journal of applied mathematics & informatics
• /
• v.29 no.1_2
• /
• pp.469-474
• /
• 2011

In a M/G/I queue where the server alternates between busy and idle periods, we assume that firstly customers arrive at the system according to a Poisson process and the arrival process and customer service times are mutually independent, secondly the system has infinite waiting room, thirdly the server utilization is less than 1 and the system has reached a steady state. With these assumptions, we analyze waiting times on the systems where some vacation policies are considered.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.16 no.2
• /
• pp.164-176
• /
• 1991

This paper considers the model of a k-out-of-n :G system with non-identical components which are subject to both forced and planned outages. For the forced outages, it assumes that there are the independent and common-cause outage events causing component failures. Then, the objective is to derive the upper and lower bounds on the mean operating time between system failures in the ample-server model. In addtion, the mean system failure times are also considered.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.280-282
• /
• 2004

According as IT environment changes from client/server system to the open system based on web service technologies, the exchange of data and services between independent applications and service servers in web environment is observed Recently. In this points, it is necessary that Geographic Information Systems, Spatial Imagery Information Systems, Intelligent Transportation Systems, and Global Navigation Satellite Systems based on the location and geometry information are inter-related each other. But, the inter-relation of these systems is very difficult because of the closed system architecture, different information format, and the absence of interoperability technologies. In this Paper, we describe 4S integration system based web service technologies that accept the international standard as WFS, WCS, WRS of OGC (OpenGIS Consortium) and UDDI, SOAP, WSDL of W3C. In detail, we study the system architecture design and implementation of traffic information service, routing service, and tracing service. These services are consisting of the data schema based on XML and GML, various functions of each layered service, each server platform, and web server. Specially, we represent that GML is being applied to a wide range of location-based services, telematics, and intelligent transportation

• Journal of the Korea Institute of Building Construction
• /
• v.21 no.6
• /
• pp.677-687
• /
• 2021

If a fire breaks out in a building, occupants can evacuate more rapidly if they are able to identify the location of the fire, the exits, and themselves. This study derives the requirements of system development, such as distance non-limitation, a non-additional device, a non-centralized server system, and low power for an emergency, to identify information about the fire and the location of evacuees. The objective is to receive and transmit information and reduce the time and effort of the database for location tracking. Accordingly, this study develops a server-independent system that collects information related to a building fire and an evacuee's location and provides information to the evacuee on their mobile device. The system is composed of a transmitting unit to disseminate fire location information and a mobile device application to determine the locations of the fire and the evacuee. The developed system can contribute to reducing the damage to humans because evacuees can identify the location of the fire, exits, and themselves regardless of the impaired server system by fire, the interruption of power source, and the evacuee's location. Furthermore, this study proposes a theoretical basis for reducing the effort required for database construction of the k-nearest neighbor fingerprint.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.10a
• /
• pp.364-367
• /
• 2000

As computer system and information/communication technology develop rapidly, nowadays CSCW(Computer Supported Collaborative Work) system appears, through which it is available to work on virtual space without any restriction of time and place. Most of Un systems depend on a special network and groupware. The systems of graphics and CAD are not so many because they are characterized by Hardware and application software. In this paper, we propose a web-based collaborative CAD system which can be jointly worked on Internet WWW being independent from any platforms. It can generate and handle objects easily using lava 3D, and it can transmit, print, and store them. The interactive work for designing objects can be also carried out through dialling with each other. This system is executed in the environment of Client/server. Clients connect to the server through lava applet on WWW. The server is implemented by lava application, and it consists of three components : connection manager which controls the contact to users, work manager which keeps viewing in concurrency and provides virtual work space sharing with others, and solid modeler which generates 3D object.

• Proceedings of the IEEK Conference
• /
• 2003.07e
• /
• pp.2391-2394
• /
• 2003

J2ME service technology has advantage that can embody independent and, more soft system in DICOM 3.0 and medicine reflex administration server, client′s OS that is medical treatment reflex standard in radio Internet. Also, intranet that do web based spread, and develop by system that can alternate existent client-server structure rapidly. Specialty, possibility of improvement is much because is connecting being limited in internet environment that medical equipment and information system of various kinds of machine are wire in medical institution and so on. Because do medical treatment reflex transmission module development applying DICOM technology and filtering techniques of "m-PACS" In this research, existence, by interlock in radio usable Mobile reflex conversion system design and embody. That is, patient′s information which is stored to various systems to be transmited and can give big help in medical examination and treatment to reflex client without being wooed doctor′s interpretation result and so on in place through environment to be radish tentacle bar see.