• Journal of Korean Elementary Science Education
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• v.35 no.1
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• pp.65-77
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• 2016

The purpose of this paper was to analyze the kinds and roles of multimedia materials in E-works that are distributed with elementary textbooks (3~6 grade) of the 2009 revised science curriculum. Five criteria (forms, goals, key competencies, inquiry process, running time) were set for this. The sample of the paper was the 784 multimedia materials in E-works of elementary science textbooks (3~6 grade) of the 2009 revised science curriculum. The results of the multimedia materials analysis are as follows: The result of the material forms of multimedia is that the form of highest ratio is text type. But all forms were used evenly in E-work. 56.2% of the multimedia materials are for "inquiry" in the goal criteria, and 65.0% of the multimedia materials are related to "science inquiry" in the key competencies criteria. Two facts indicate many multimedia is used to develop students' inquiry ability. However the ratio of multimedia materials in motivation step is higher than that in inquiry activity step. In analysis of running time, the ratio of "under 5 min" multimedia materials is the highest. But, the ratio of 5~10 min multimedia materials in inquiry part is higher than that in motivation part in The Chi-square test between "running time" and "parts" that consist of motivation part and inquiry part. Through the analysis of module and the categorizing the multimedia materials, we found that the multimedia materials play eleven roles in E-works that are distributed with elementary textbooks.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1059-1075
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• 1997

The transprot layer protocol for distrubuted multimedia applications in high speed network should gurantee the Quality of Serivce(QoS)requested by uwer.,The QoS Parmenters can be divied into two calssifications:those depend on the speed of a network such as bandiwidth,end-to-end transmission delay and throughput;and net- woek independent parameters such as various typed of group communications, retransmission method based on multimeda characteristic,acceptable packet wrror rate and transmission priority.In this proposed protocol,we divided user's QoS into performance redated parmeters and non-performance related parameters.The perform- ance-related paramenters are mapped into ATM traddic paramenters by the Distributed QoS Manger(DQM),the QoS manager,and the non-performance redlted paramenters are supported by the Distributed Multimedia Trans-port protocol(DMTP),a high-performance group transport protocol.Especially,becaues the DMTP is designed with considering the IP protocol,it can be efficiently used as an underlying protocol not onlu in ATM,but also in Ethernet,Token ring and FDDI LAN.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4948-4967
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• 2017

On mobile devices, image sequences are widely used for multimedia applications such as computer vision, video enhancement, and augmented reality. However, the real-time processing of mobile devices is still a challenge because of constraints and demands for higher resolution images. Recently, heterogeneous computing methods that utilize both a central processing unit (CPU) and a graphics processing unit (GPU) have been researched to accelerate the image sequence processing. This paper deals with various optimizing techniques such as parallel processing by the CPU and GPU, distributed processing on the CPU, frame buffer object, and double buffering for parallel and/or distributed tasks. Using the optimizing techniques both individually and combined, several heterogeneous computing structures were implemented and their effectiveness were analyzed. The experimental results show that the heterogeneous computing facilitates executions up to 3.5 times faster than CPU-only processing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2778-2791
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• 2017

In the age of big data, distributed data providers need to ensure the privacy, while data analysts need to mine the value of data. Therefore, how to find the privacy-utility tradeoff has become a research hotspot. Besides, the adversary may have the background knowledge of the data source. Therefore, it is significant to solve the privacy-utility tradeoff problem in the distributed environment with side information. This paper proposes a distributed privacy-utility tradeoff method using distributed lossy source coding with side information, and quantitatively gives the privacy-utility tradeoff region and Rate-Distortion-Leakage region. Four results are shown in the simulation analysis. The first result is that both the source rate and the privacy leakage decrease with the increase of source distortion. The second result is that the finer relevance between the public data and private data of source, the finer perturbation of source needed to get the same privacy protection. The third result is that the greater the variance of the data source, the slighter distortion is chosen to ensure more data utility. The fourth result is that under the same privacy restriction, the slighter the variance of the side information, the less distortion of data source is chosen to ensure more data utility. Finally, the provided method is compared with current ones from five aspects to show the advantage of our method.

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.245-253
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• 2005

The multimedia ad hoc wireless network is quite an attractive issue since it offers a flexible solution to enable delivery of multimedia services to mobile end users without fixed backbone networks. However, with the unique design challenges of ad hoc wireless networks, it is a non-trivial issue to provide bounded delay guarantee, with fair share of resources. In this paper, we proposed distributed implementation of the delay guaranteed fair queueing (DGFQ) scheme in multimedia ad hoc wireless networks. Through the the results of performance evaluation, we can conclude that DGFQ also performs well to control bounded delay in multimedia ad hoc wireless networks.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.983-986
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• 2005

This paper describes a digital convergence platform(DCP) whice is implemented based on the MPEG-21 multimedia framework. The DCP is a newly proposed solution in this research for the convergence service of future home multimedia environment. The DCP is a common platform designed to have the feature of configurability, via means of S/W, which is needed for the convergence service of diverse digital media. A distributed peer to peer service and transaction model is also a new feature realized in the DCP using the MPEG-21 multimedia framework. A prototype DCP is implemented to verify its functions of multimedia service and transactions. The developed DCPs are networked with IP clustering storage systems for the distributed service of multimedia. Successful streaming services of the MPEG-2/4 video and audio are verified with the implemented test-bed system of the DCP.

• Journal of Korea Multimedia Society
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• v.18 no.4
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• pp.452-459
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• 2015

Three synchronization issues, i.e., phase, frequency, and symbol time, have to be properly controlled to achieve distributed beamforming gain. In this paper, the impacts of synchronization errors in distributed beamforming are analyzed for both single-carrier and OFDM systems. When the channel is constant over a symbol duration, the performance degradation due to phase offset is the same for both single-carrier and OFDM systems. For symbol timing offset in OFDM systems, high frequency subcarriers are more susceptible as compared to low frequency ones. Frequency offset is critical in OFDM systems since it leads to interference from the other subcarriers as well as power loss in the desired signal.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.461-465
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• 2009

Normally, a distributed computing environment is flexible in controlling complex embedded systems but their software components are becoming complex as these systems are equipped with several platforms and attached to various electronic devices, sensors, and actuators. These systems requires inter-object communication mechanisms to provide fault tolerant and QoS-enabled middleware service support in a distributed system. Generally, a middleware performs analysis of the parameters to ensure the availability and reliability of data dissemination. This paper focuses in particular to designing an application middleware for the specific scenario to improve the high availability and fault tolerance of data thus improving the QoS (Quality of Service) of a distributed system. The performance of an adaptive and highly reliable middleware can be significant based on the selection of vital parameters of the system.

• Journal of Korea Multimedia Society
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• v.21 no.9
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• pp.1090-1098
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• 2018

MQTT is a lightweight messaging protocol that can be used for low power IoT devices. The MQTT basically uses single MQTT broker to indirectly share message information between publishers and subscribers. This approach has a weakness in regard to traffic overflow, connection fault, security, etc. In this paper, we propose a distributed MQTT broker architecture that solves the problems in single MQTT broker structure. The distributed MQTT broker architecture is expected to support new application services that cannot be supported by a conventional MQTT architecture. We have designed and implemented a distributed MQTT broker architecture based on the RPL protocol that has been widely used for IoT network. The experiment results show that the proposed MQTT broker architecture represents better publishing/subscribing latency and network stability than the conventional MQTT broker architecture.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.755-765
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• 2004

Recently, the Internet-based distributed/parallel computing using many of idle hosts has been demonstrated its usefulness for processings of a large-scale task and involving several important issues. While executing a large-scale task, the realtime monitoring is required for adaptive strategy of the performance and state change of host. This paper provides the realtime monitoring and visualization on global computing infrastructure called PDP(Parallel Distributed Processing) which is a parallel computing framework implemented with Jana for parallel computing on the Internet.