• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.476-489
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• 1999

HW/SW codesign is integrated design of systems implemented using both hardware and software components. Many design tools has been developed to support this new paradigm, so far. Current codesign tools are not widely used as been expected because of variety problems - rapidly evolving technology, platform dependency, absence of standard specification method, inconsistent user interface, varying target system, different functionality In this paper, we propose a web-based distributed HW/SW codesign environment to remedy this kinds of problem. Our codesign environment has object-based 3 tier client/server architecture. It supports collaborative workspace through session service. Fully object-oriented design of user interface(OOUI) enables easy extension without change of user Interface. Furthermore it contains transaction server and security server for efficient and safe transfer of design data. To show a validity of our design, we developed prototype of web-based HW/SW codesign environment called WebCEDA. Our model of HW/SW codesign can be used for web-based generic CAD tools.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.80-90
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• 2010

In this paper, we introduce some issues to implement an agent system to support service mobility in home network environment, and describe detailed design method in terminal as well as server agent. Specifically, we describe user recognition module, signaling message receiving/parsing module of terminal agent and signaling message receiving/parsing module, multimedia switching module, memory management module of server agent. We define several parameters managed in IP sharing device and design binding table structure to support mobility. And we utilize M/M/1/K queueing theory to obtain relations between memory size, blocking probability and memory utilization. From the obtained results, we show that memory size can be predicted in server agent mounted on IP sharing device.

• Journal of Korea Multimedia Society
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• v.15 no.6
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• pp.814-826
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• 2012

In this paper, we propose scheduling algorithms for transporting variable-bit-rate video stream using playback buffer level of the clients over wireless communication networks. The proposed algorithms attempt to maximize the utilization of limited bandwidth between the central video server and the clients over a mobile network. Since a video server may serve several video request at the same time, it is important to allocate and utilize network bandwidth to serve them fairly and efficiently. In order to improve the quality of service and real-time performance of individual video playback, the video server attempts to allocate temporarily more network bandwidth to serve a video request with the lower buffer level preferentially. The simulation results prove the fair service and load balancing among the mobile concurrent clients with different buffer levels and hence maximizing the number of frames that are transported successfully to the client prior to their playback times.

• Journal of Korea Multimedia Society
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• v.9 no.1
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• pp.101-108
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• 2006

Developing a network game that is serviced on the internet requires a lot of work, time and manpower. Therefore, it is important to design a game in such a way so that existing design codes could be used. The database for the multi-player network game is accessed from many clients. To manage the resource effectively, it is required to design the APIs to be minimized the database access and to be dealt with the related data efficiently. For this, it is needed to apply the object-oriented design for the related software modules. In the paper, we propose the design patterns of GoF to implement the APIs thatis needed to deal with the database resource. The database design through the analysis of some game's GUI has the advantage to create the optimized schema set more quickly, because it minimize the review step and the modification step of the database design generally. In addition, we apply to the design patterns of GoF for the APIs design of the server-side database. These reduce the times of the program call between the game server and the database server. These also make easily the maintenance for the already developed APIs, and it makes easily the addition of new APIs.

• Journal of Korea Multimedia Society
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• v.5 no.5
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• pp.488-493
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• 2002

MPEG-4 movies are composed of several media objects, organized in a hierarchical fashion. Those media objects are served to the clients as elementary streams. To play the movie, client players compose the elementary streams according to the meta- information called the scene graph. The meta-information streams are delivered as BIFS and OD elementary stream. Using dynamically generated BIFS and OD streams, we can provide a service something differs from traditional file services. For example, we can insert weather or stock information into the bottom of the screen while an existing movie was played in the screen. In this paper, we propose a dynamic service framework and dynamic server. Dynamic service framework is an object-oriented framework dynamically generating BIFS and OD streams based on the external DB information. Dynamic server provides a GUI for the server management and interface for registering dynamic services. In this framework, the dynamic service has the same interface as a file service. So, a dynamic service is considered as a file service by clients and other services.

• Journal of Digital Contents Society
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• v.2 no.1
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• pp.73-79
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• 2001

Most of the existing algorithms try to disseminate the multimedia contents of internet service provider(ISP), without taking into account the needs and characteristics of specific websites including e-learning systems with web-based .educational contents. Sometimes the client must select the best one among the replicated repositories. However, this is a less reliable approach because clients' selections are made without prior information on server load capacity. In this paper we propose an agent system inspired by the need of improving QoS of delivering web-based educational multimedia contents without incurring long access delays. This agent system consists of three components, Analyzer, Knowledge Base, and Automaton embedded the capacity algorithm. It analyzes and investigates traffic information collected from individual replicated server by learners' requests, and selects a server which is available and is expected to provide the fastest latency time and the lowest loaded capacity, and achieves high performance by dynamic replicating web resources among multiple repositories.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.53-59
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• 1999

The CAI has not been developed with the non-structural form of interactive courseware under classroom network. This study suggests the direction of enhancement for students' achievement through interaction between learner and learner. and teacher and learner applied the effective multi-presentation and 4he introduction of the concept of chatting client/server to class with the use of multimedia package. For the continuous development of courseware and the effectiveness of keeping and repairing materials. this study consists of development of the teaching materials by Powerpoint which is one of the multimedia package presentation tools, and teaching method through discussion by chatting client/server under the classroom network. This new CAI showed the possibility of the open education through discussion and the enhancement of learners' effective achievement in the result of the data got from the classrooms of elementary, middle and high schools.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.250-258
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• 2011

In this paper we propose a load balancing scheme for heterogeneous multiple AS's (Application Server) in IMS (IP Multimedia Subsystem) based network. In IMS network, to perform load balancing among multiple ASs with different registration pattern, different weight value should be set for each AS. In previous systems, there exists an inconvenience that the weight value should be set manually by the operator after monitoring the result. In this paper we propose a method to calculate optimal weight in automatic manner and to perform load balancing simultaneously. We also propose a simplified algorithm to reduce calculation in specific situation and present a way to apply our proposed scheme in adaptive manner according to the situation. Through simulation result, we verify that our proposing scheme outperforms previous schemes in load balancing and adjusts well to the change of the system in automatic manner with fast convergence.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.451-458
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• 2005

The transcoding is a solution which is able to adapt to heterogeneous clients of requesting a different playback rate of multimedia data. Thus, The transcoding needs decoding and encoding. In general, previous studies to reduce complexity have a problem, the degradation of visual quality On the contrary, previous studies to reduce the degradation of visual quality lead to heavy computation. Thus, many researchers have studied a solution between the complexity and the degradation of visual quality. But until now, most researches of this region have dealt with the transcoder itself, such researches about a server's assistance to improve the performance of transcoder is rarely studied. In case of servicing multimedia data to heterogeneous clients which have low capabilities, the assistance of server side is able to reduce frames with processing in the transcoder and improve the performance of the transcoder. Thus in this paper, we propose the frame-skipping transcoder system architecture that takes into consideration transcoder and server side to reduce the complexity of the transcoder.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.69-77
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• 2019

Today, most of elevators have an emergency call facility for emergency situations. However, if the network installed in the elevator is also out of power, it cannot be used for the elevator remote monitoring and management. So, we develop an integrated and unified emergency call system, which can transmit not only telephone call but also data signals using PSTN(Public Switched Telephone Network) in order to remote monitoring and management of elevators, even though a power outage occurs. The proposed integrated emergency call system to process multiple data such as voice and operational information is a multi-channel board system which is composed of an emergency phone signal processing module and an operational information processing module in the control box of elevator. In addition, the RMS(remote management server) systems based on the Web consist of a dial-up server and a remote monitoring server where manages the elevator's operating information, status records, and operational faults received via the proposed integrated and unified emergency call system in real time. So even if there's a catastrophic emergency, the proposed RMS systems shall ensure and maintain the safety of passengers inside the elevator. Also, remote control of the elevator by this system should be more efficient and secure. In near future, all elevator emergency call system need to support multifunctional capabilities to transmit operational data as well as phone calls for the safety of passengers. In addition, for safer elevators, it is necessary to improve them more efficiently by combining them with high-tech technologies such as the Internet of Things and artificial intelligence.