• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.128-135
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• 2003

A fairness control method for Distributed-Queue Dual-Bus(DQDB) has been studied under specific traffic types such as equal probability traffic, symmetric traffic and asymmetric traffic. To distribute DQDB network bandwidth fairly to all stations under general traffic such as a client-server traffic that differs from specific traffic types, we propose an effective fairness control method. Based on an access limit, the proposed mechanism applies two bandwidth control mechanisms to DQDB networks. One is the mechanism that is called APS(Access Protection Scheme) for servers. And another is the mechanism that controls the allocation of bandwidth only using an access limit lot clients. Simulation results show that it outperforms other mechanisms.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.22-29
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• 1999

In video-on-demand systems, movies are striped across the disks of the array in a video server to support multiple access. The blocks of the movies have to be placed carefully on the disks of the array in a video server in order to avoid load imbalance across these disks as well as to achieve maximum utilization of both space and bandwidth of these disks. This paper proposes a movie placement method called the GARR (group-alternation round-robin) that is based on the dynamic disk striping method considering the popularity of movie. The GARR uses group-alternation as movie selection policy and round-robin as data placement policy, where group-alternation allocates popular movie and unpopular movie groups to disks alternately. The performance of the GARR is evaluated by simulations.

• Journal of Korea Multimedia Society
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• v.13 no.6
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• pp.901-910
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• 2010

$IP^2$, as an extended concept of the next generation IMT network, is a concept of basically supporting mobility using two steps of IP address (i.e. IPha (IP Host address) and IPra (IP routing address)) in IP backbone network. Current $IP^2$system has a shortcoming of excess usage of network resources caused by sending paging messages to all cells in LA (Location Area) in paging procedure. Considering the evolving direction of network, which is taking mobility with various speed and integration of devices into consideration, this shortcoming must be overcome. In this paper, we proposed a method to reduce time and memory for paging by maintaining current information of MN (Mobile Node) not in Active state with proxy server. Performance evaluation based on NS-2 simulations has shown that the efficiency of network resources is improved in the proposed method.

• Journal of Korea Multimedia Society
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• v.11 no.3
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• pp.398-403
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• 2008

Data broadcasting is a mechanism to transmit information to clients in simplex transmission environments. In this mechanism, server transmits to repeat all information to all users and users use a necessary data when the data is transmitted. Therefore users are waiting the necessary data until the data is transmitted. It is important to reduce user's waiting time. Server schedules the data to reduce waiting time. In this paper, we study efficient data scheduling algorithm. The result shows that the performance of the proposed method is increased 13 percent compared to the method considering only request frequency.

• Journal of information and communication convergence engineering
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• v.3 no.3
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• pp.157-162
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• 2005

Web services are key applications in business­to-business, business-to-customer, and enterprise applications integration solutions. As the mobile internet becomes one of the main methods for information delivery, mobile Web Services are regarded as a critical aspect of e-business architecture. In this paper, we proposed a mobile Web Services middleware that converts conventional internet services into mobile Web services. We implemented a WSDL (Web Service Description Language) builder that converts HTML/XML into WSDL and a SAOP (Simple Object Access Protocol) message processor that performs SOAP message handling, chain and handling of server requests. The former minimizes the overhead cost of rebuilding mobile Web Services and enables seamless services between wired and wireless internet services. The latter enhances SOAP processing performance by eliminating the Servlet container (Tomcat), a required component of typical Web services implementation. Our main contributions are to overcome the latency problem of current Web Services and to provide an easy mobile Web service implementation. Our system can completely support standard Web Services protocol, minimizing communication overhead, message processing time, and server overload. Finally we compare our empirical results with those of typical Web Services.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.63-68
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• 2016

Environmental downtime produces a significant cost to organizations and makes them unable to do business because what happens in the data center affects everyone. In addition, the amount of electrical energy consumed by data centers increases with the amount of computing power installed. Installation of physical Information Technology and facilities related to environmental concerns, such as monitoring temperature, humidity, power, flood, smoke, air flow, and room entry, is the most proactive way to reduce the unnecessary costs of expensive hardware replacement or unplanned downtime and decrease energy consumed by servers. In this paper, we present remote system for monitoring datacenter implementing using open-source hardware platforms; Arduino, Raspberry Pi, and the Gobetwino. The sensed data displayed through Arduino are transferred using Gobetwino to the nearest host server such as temperature, humidity and distance every time an object hitting another object or a person coming in entrance. The raspberry Pi records the sensed data at the remote location. The objective of collecting temperature and humidity data allows monitoring of the server's health and getting alerts if things start to go wrong. When the temperature hits $50^{\circ}C$, the supervisor at remote headquarters would get a SMS, and then they would take appropriate actions to reduce electrical costs and preserve functionality of servers in data centers.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.11
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• pp.35-45
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• 1999

This paper presents an interconnection network for load balancing on a multimedia server and proposes a simple probabilistic model of the interconnection network for analysing the traffic characteristics. Because the switch uses deflection algorithm for routing, the traffic load on the switch seriously affects deflection probability. In this paper, we trace the deflection probability as a function of the traffic load according to the model. By comparing the result with the empirical result, we prove that the model is useful for estimating the deflection probability and traffic saturation point against the amount of packets getting into the switch.

• Journal of Korea Game Society
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• v.14 no.5
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• pp.25-34
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• 2014

In this paper, the weak point of AOS jenre online game which occupies the majority of Korea game market of 2014 year is analyzed and to solve the problem, the enhanced design and implementation content is introduced. The proposed game is based on the custom AOS jenre format but has the TPS view and nontargeting format to enhance the action feel. To enhance the game quality, graphics, animation, effect and sound resources are organized. Game server is implemented by multithread of IOCP model to support many clients. The technical issue and design method of client and server are described.

• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.698-708
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• 1997

To construct distance learing servers and provide their service using the WWW(World Wide Web), it is necessary that we use a real-time processing mehtod rather than the processing after downloading method for multimedia data transmission and their processing.To fulfill such requirements, we developed a real-time processing muduloe for distance education which can process multimedia data in AVI and WAV formats in distrbuted eviroments.We in turn developede a real-time WWW server that can provide real-time services of hypertxt and motion poctures data in temsw of adding the real-time porcessing modute to the MuX framework and intergarting them with WWW. We frnally developed as distance lerming system for real-time interactive chinese character learming, bassed on the results from the pre-vious steps.

• The KIPS Transactions:PartB
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• v.12B no.2 s.98
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• pp.167-172
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• 2005

A rapid growth in the number of Internet users and in massive media contents tends to cause server overload and high network traffic. As a consequence, it can be safely assumed that the quality of service is on the brink of deterioration. A solution of this problem is the development of the Content Distribution Network. Therefore, in this paper, we propose a transmission model using CDN. This model uses regional media server which closes to client, and uses MDC coding and multi-channel to reduce packet loss and delay. In conclusion, this study improved performance of multimedia service by reducing packet loss and delay.