• The Journal of Society for e-Business Studies
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• v.13 no.3
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• pp.67-83
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• 2008

Web caching server is one of the important components of any web site, as it makes the access of users to web content much faster while balancing the network and server load. There are many caching approaches proposed in order to solve this problem. Classically, we know several caching algorithms like FIFO, LRU, LRU-min and etc. Most of them have their advantages and disadvantages based on specific context. The purpose of this paper is to introduce the new concept of caching objects along with their related content and test the performance of the proposed caching method using CPN Tools simulator program. It is generally known that the use of Colored Petri Nets(CPNs) for modeling the simulation of new idea is one of the popular methods of system evaluation throughout software development projects. Moreover it could be very handy in describing the overall logic of the system. The CPN Tools is one of the most robust simulator programs which supports all necessary tools and functions to build and run the simulation model for CPN. Therefore in this paper, we will use CPN Tools software in order to build a simulator for our innovative caching approach named as web caching with related content. Then we will analyze the results derived from the simulation of our model and will make corresponding conclusions.

• Journal of Korea Game Society
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• v.2 no.1
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• pp.42-48
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• 2002

Many web-based simulation environments have been proposed to create models and execute simulation through the Web. Although web-based simulation has the advantage of utilizing many computers connected to Internet, overhead of the web server and heavy traffic caused by Java RMI degrade the performance and scalability of simulation. In this paper, we design and implement web-based distributed simulator using Java for the scalability and performance. In addition, we can apply the proposed simulator to create model server and client engines in online game. We apply the proposed simulator to simulate ATM switch queueing model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.123-127
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• 2004

The present system of medium and large size ship when that's ship came alongside the pier, are not systemic. The steersman only depend on radio-communication, not visuality. This treatise bridge a gap of current system from development of simulation program The main-server get a distance from ship to peer and ship's direction using longitude and latitude, heading, rate. The steersman of main ship and tug will see all situation with PDA client program. The PDA client program directly display a location information from main-server. And ship's most suitable path be calculated simulation program using database system. This method will induce more detail situation information and the most suitable path when the ship coming alongside the pier.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.222-231
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• 2004

LCS(Launch Control System) in Space Center performs the ground and flight tests of launch vehicle. Those tests require data monitoring and control functions to the external systems such as launch vehicle, launch pad, and propellant supply system, etc. The LCS is composed of real time control system, simulation system, data server, external network, etc. The purpose of the simulation system is to simulate launch vehicle, and it is used for evaluation test of the LCS. This paper described the simulation system overview, the concept design, and the real time data processing evaluation tests of the simulator, gateway, data distribution server which are constituents of the simulation system.

• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.69-81
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• 2003

To manage a cluster of distributed server systems, a number of management aspects should be considered in terms of configuration management, fault management, performance management, and user management. System performance monitoring and reporting take an important role for performance and fault management. In this paper, we present distributed system architecture modeling of a performance monitoring and reporting tool. Modeling architecture of four subsystems are introduced: node agent, data collection, performance management & report, and DB schema. The performance-related information collected from distributed servers are categorized into performance counters, event data for system status changes, service quality, and system configuration data. In order to analyze those performance information, we use a number of ways to evaluate data corelation. By using some results from a real site of a company and from simulation of artificial workload, we show the example of performance collection and analysis. Since our report tool detects system fault or node component failure and analyzes performances through resource usage and service quality, we are able to provide information for server load balancing, in short term view, and the cause of system faults and decision for system scale-out and scale-up, in long term view.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.29-39
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• 2011

The appointment system is widely used to facilitate customer access to service in many industries including healthcare and others. Because of its importance, much research has investigated how to build an effective appointment policy under various environments. However, most research has considered a single-server service system. The objective of this work is to evaluate several appointment policies in a two-stage service system in which multiple servers are available and build separate appointments at the second-stage. In such a system, we propose and evaluate the staggering appointment policy. Simulation experiments indicate that the proposed staggering appointment policy outperforms other traditional appointment policies in terms of customer waiting time, server idle time, and the number of customers who are later to scheduled appointments.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.556-560
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• 2002

In this paper, we propose a remote controller for robot manipulator using local area network(LAN) and internet. To do this, we develope a server-client system as used in the network field. The client system is in any computer in remote place for the user to log-in the server and manage the remote factory. the server system is a computer which controls the manipulator and waits for a access from client. The server system consists of several control algorithms which is needed to drive the manipulator and networking system to transfer images that shows states of the work place, and to receive a Tmp data to run the manipulator The client system consists of 3D(dimension) graphic user interface for teaching and off-line task like simulation, external hardware interface which makes it easier for the user to teach. Using this server-client system, the user who is on remote place can edit the work schedule of manipulator, then run the machine after it is transferred and monitor the results of the task.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.201-208
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• 2001

Explosive growth of the Web and the non-uniform characteristics of client requests result in the performance degradation of Web servers, and server cache has been recognized as the solution. We analyzed Web server accessing characteristics-repetition, size, and locality of access. Based on the result, we analyzed the cache removal policies and proposed a prefetch strategy to improve the hit ratio of server caches. In addition, through the trace-driven simulation based on the traces from real Web sites, we showed the performance improvement by our proposal.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.165-172
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• 2017

Some duplicate processes are happen in developing games under the diverse platforms. Implementing functions. like processing and managing data, in every platforms have an influence on game development. In this paper, we propose a multi-platform server framework that can simulate combat games such as one server on any platform. It was designed to be easy to debug using a protocol consisting of attribute-value pairs by the JSON data format. Since it is independent of the programming language, it has the advantage of being able to communicate with various languages. The server proposes a model that can easily upgrade the structure or the specification using the Amazon web server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.304-311
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• 2005

OCSP has specific characters which can suspend, close, and correct in real time. But, as more clients use the OCSP server verification, more updated information is needed, which can lead to jamming in the OCSP server. To apply this technique of Distributed OCSP server so as to reduce the certificate verification OCSP from jamming. Also, the Distributed OCSP server will solve the problems of the intensive central structure. Simulation results show that the average reply time of certificate verification request and server load are reduced in the case using distributed OCSP. In addition to this advantage, resource distribution and fault tolerance are acquired because of multiple OCSP.