• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.303-307
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• 2002

Virtual hosting is a typical service to connect each directory of site and domain name. If traffic amounts may increase at one site present in the server, then it affects traffic amounts of other sites as well (including the sites which have flew requests). To overcome this problem, we suggest a simple feedback-control concept for the system by periodically monitoring the traffic and properly actuating traffic dispersions by investigating the log file. Specifically, large files are to be served in a backup server (to reduce the workload of the main server) by changing their own URL's in html format. In other words, it automatically redistributes the workload by using the URL. Furthermore, we also use the redirecting method by just adding html tags to html header. This method efficiently handles the workload and maintains the capability of the server effectively to the varying workload.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.27-34
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• 2003

A distributed server cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.6
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• pp.1-12
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• 2016

In this paper, we consider a general discrete-time queueing system with D-BMAP(discrete-time batch Markovian arrival process) and D-policy. An idle single server becomes busy when the total service times of waiting customer group exceeds the predetermined workload threshold D. Once the server starts busy period, the server provides service until there is no customer in the system. The steady-state workload distribution is derived in the form of generating function. Mean workload is derived as a performance measure. Simulation is also performed for the purpose of verification and a simple numerical example is shown.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.1
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• pp.89-99
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• 2020

In this paper, we consider a dyadic server control policy that combines workload control and single vacation. Customer arrives at the system with Bernoulli process, waits until his or her turn, and then receives service on FCFS(First come first served) discipline. If there is no customer to serve in the system, the idle single server spends a vacation of discrete random variable V. If the total service times of the waiting customers at the end of vacation exceeds predetermined workload threshold D, the server starts service immediately, and if the total workload of the system at the end of the vacation is less than or equal to D, the server stands by until the workload exceeds threshold and becomes busy. For the discrete-time Geo/G/1 queueing system operated under this dyadic server control policy, an idle period is analyzed and the steady-state queue length distribution is derived in a form of generating function.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.2
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• pp.29-39
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• 2018

In this paper, we discuss a discrete-time queueing system with dyadic server control policy that combines workload control and multiple vacations. Customers arrive at the system with Bernoulli arrival process. If there is no customer to serve in the system, an idle single server spends a vacation of discrete random variable V and returns. The server repeats the vacation until the total service time of waiting customers exceeds the predetermined workload threshold D. In this paper, we derived the steady-state workload distribution of a discrete-time queueing system which is operating under a more realistic and flexible server control policy. Mean workload is also derived as a performance measure. The results are basis for the analysis of system performance measures such as queue lengths, waiting time, and sojourn time.

• Journal of the Korea Society for Simulation
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• v.12 no.4
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• pp.103-111
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• 2003

A distributed sewer cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.65-72
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• 2007

This paper aims to provide information to generate a statistical load model of an educational server by analyzing workload of an e-Learning sewer at Dankook University. The result of the analysis shows file size distribution, access frequency and transmission volume for each file type, access interval, changes in preference and clients access rate by networks. In particular, it had different results from previous studies about video file's size distribution and file distribution based on access frequency. This is because the characteristics of e-learning are influenced by using authoring tools for making into video file and by freeing the number of students who register for a course. The result in this paper can be used as a basic data for studies designed to improve e-learning system architecture and server performance.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3732-3838
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• 2000

As the Internet sites and users have rapidly been increased, the development for search engines has also been accelerated to satisfy users' expectations. As the result, not only the action of collecting documents through many search engines gave hosts workload, but also regular updating all the information is needed since information is newly added. With the circumstances, the necessity of the technology to collect massive information in hosts has been increased for the speed which is a basic requisite of search systems, and for more accurate collection of documents. Also, the role of search engines grows bigger for Internet users' various demands and flexible process through World Wide Web. In this paper, we design and implement a robot agent and a remote control system which doesn't give an excessive workload on a target server and makes the collection of documents done in a short period by considering an average workload rate on the target server and the rate of the workload that a robot experience in collection time, after we compare and analyze the existing Robot Agent Systems and supplement their weak points.

• Journal of Korea Game Society
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• v.19 no.3
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• pp.5-14
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• 2019

The gaming server is based on a distributed server. In order to distribute workloads of gaming servers, distributed gaming servers apply some algorithms which divide each of gaming server's workload into balanced workload among the gaming servers and as a result, efficiently manage response time and fusibility of server requested by the clients. In this paper, we propose a load balancing agent using PPO(Proximal Policy Optimization) which is one of the methods from a greedy algorithm and Policy Gradient which is from Reinforcement Learning. The proposed load balancing agent is compared with the previous researches based on the simulation.

• Journal of Biomedical Engineering Research
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• v.26 no.2
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• pp.65-71
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• 2005

The main obstacles for adopting a mobile health information system to existing hospital information system are the redundancy of clinical data and the additional workload for implementing the new system. To obtain a seamless communication and to reduce the workload of implementation, an easy and simple implementation strategy is required. We propose a mobile clinical information system (MobileMed) which is specially designed for the easy implementation. The key elements of MobileMed are a smart interface, an HL7 message server, a central clinical database (CCDB), and a web server. The smart interface module transfers the key information to the HL7 message server as new clinical tests data is recorded in the existing laboratory information system. The HL7 message server generates the HL7 messages and sends them to the CCDS. As a central database the CCDS collects the HL7 messages and presents them to the various mobile devices such as PDA. Through this study we might conclude that the architecture for the mobile system will be efficient for real-time data communication, and the specially designed interface will be an easy tool for implementing the mobile clinical information system.