• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.426-433
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• 2010

The H.264/AVC video coding standard performs inter prediction using variable block sizes to improve coding efficiency. Since we predict not only the motion of homogeneous regions but also the motion of non-homogeneous regions accurately using variable block sizes, we can reduce residual information effectively. However, each motion vector should be transmitted to the decoder. In low bit rate environments, motion vector information takes approximately 40% of the total bitstream. Thus, motion vector competition was proposed to reduce the amount of motion vector information. Since the size of the motion vector difference is reduced by motion vector competition, it requires only a small number of bits for motion vector information. However, we need to send the corresponding index of the best motion vector predictor for decoding. In this paper, we propose a new codeword table based on the phased-in code to encode the index of motion vector predictor efficiently. Experimental results show that the proposed algorithm reduces the average bit rate by 7.24% for similar PSNR values, and it improves the average image quality by 0.36dB at similar bit rates.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.25-35
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• 2020

Recently, the development of image processing technology, as well as hardware performance, has been continuing the research on 3D point processing technology that provides users with free viewing angle and stereoscopic effect in various fields. Point cloud technology, which is a type of representation of 3D point, has attracted attention in various fields because it can acquired/expressed point precisely. However, since Hundreds of thousands, millions of point are required to represent one 3D point cloud content, there is a disadvantage that a larger amount of storage space is required than a conventional 2D content. For this reason, the MPEG (Moving Picture Experts Group), an international standardization organization, is continuing to research how to efficiently compress, store, and transmit 3D point cloud content to users. In this paper, a V-PCC bitstream generated by a V-PCC (Video-based Point Cloud Compression) encoder proposed by the MPEG-I (Immersive) group is composed of an MPU (Media Processing Unit) defined by the MMT. In addition, by extending the signaling message defined in the MMT standard, a parameter for a segmented transmission method of the 3D point cloud content by area and quality parameters considering the characteristic of the 3D point cloud content, so that the quality parameters can be selectively determined according to the user's request. Finally, in this paper, we verify the result through design/implementation of the verification platform based on the proposed technology.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.665-671
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• 2020

MPEG-I is actively working on standardization on the coding of immersive video which provides up to 6 degree of freedom (6DoF) in terms of viewpoint. 3DoF+ video, which provides motion parallax to omnidirectional view of 360 video, renders a view at any desired viewpoint using multiple view videos acquisitioned in a limited 3D space covered with upper body motion at a fixed position. The MPEG-I visual group is developing a test model called TMIV (Test Model for Immersive Video) in the process of development of the standard for 3DoF+ video coding. In the TMIV, the redundancy between a set of input view videos is removed, and several atlases are generated by packing patches including the remaining texture and depth regions into frames as compact as possible, and coded. This paper presents an atlas generation method that removes small-sized blocks in the atlas for more efficient 3DoF+ video coding. The proposed method shows a performance improvement of BD-rate bit savings of 0.7% and 1.4%, respectively, in natural and graphic sequences compared to TMIV.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.341-354
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• 2005

The main bottleneck for large scale VOD systems is bandwidth of storage or network I/O due to the large number of client requests simultaneously, and then efficient techniques are required to solve the bottleneck problem of the VOD system. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD system through the use of multicast scheme. In this paper, we propose a new patching scheme, called P2P proxy patching, for improving the typical patching technique by jointly using the prefix caching and P2P proxy. In our proposed scheme, each client plays a role in a proxy to multicast a regular stream to other clients that request the same video stream. Due to the use of the P2P proxy and the prefix caching, the client requests that ive out of the patching window range can receive the regular stream from other clients in the previous patching group without allocating the new regular channels from the VOD server to the clients. In the performance study, we show that our patching scheme can reduce the server bandwidth requirement about $33\%$ less than that of the existing patching technique with respect to prefix size and request interval.

• Journal of Elementary Mathematics Education in Korea
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• v.13 no.1
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• pp.97-114
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• 2009

The purpose of this study was to investigate the effects of digital mathematics textbook on spatial abilities, interest and achievement of 6th graders. For this, research questions were set as follow: A. Is there any difference in cognitive ability in the space perception test between the experimental group and the control group. B. What distinctive attributes exist between the experimental group and the control group in the Spatial abilities? C. Is there any difference in learners' interest and achievement between the experiment group and the control group. To investigate the research questions, two classes of 6th grade children were selected from an elementary school in Daejeon and assigned one as experimental group and the other as control group. The experimental group studied mathematics using Digital Textbooks under an individual PC environment while the control group studied using the existing book-type textbooks. The following results and conclusions were obtained from the research. First, the effect of the Digital Textbooks on children's mathematics achievement was not statistically meaningful even though there was some progress in children's achievement. Furthermore, it was not found that the usage of a Digital Textbooks consistently influenced improvement in the students' interest in mathematics. Second, there were some positive changes in the achievement of Spatial ability of the middle subgroup of pretest score in the experiment group. It can have some educational implication that the Digital Textbooks can affect positively to the middle group in mathematics achievement who dominated more than 50% of the class. Third, the number of correct answers was found to be somewhat higher than that of the control group in spatial reasoning items. This means that the learning environment with Digital Textbooks allow more opportunities for manipulating geometric objects physically and mentally. Therefore, It seems necessary to offer various resources such as digital contents for students' geometric learning. For future research, It is strongly recommended to fix the bugs of the digital textbook programs and to upgrade the operating system of the computer.

• Trans-
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• v.4
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• pp.111-134
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• 2018

The purpose of this study is to understand the principles of Balletfit and its program structure and to establish Balletfit's effects on body shape change and postural correction. Interview, the most commonly used method of qualitative research, was chosen as the research method. Ten Balletfit class participants, who have attended private lessons twice per week, for three to six months period of time, were selected. These participants were chosen from participants of private lessons instead of group lessons for in-depth insights. The research was limited to a small group of participants and therefore, it is difficult to standardize the result. Also, because this study is based on the opinions of the participants, not by a posture measuring device, the accuracy of the result is limited as well. The followings are the conclusion of this research. First, the participation motive was either internet research or acquaintance's recommendation. Secondly, the effort to change the body shape. After experiencing Balletfit classes, the participants became aware of their body and made an effort to recover their posture by holding the stomach tight and sitting up correctly. Thirdly, their posture became ideal. Most participants became aware of what an ideal posture is and as their body became ideal, the participants also recovered their health by becoming aware of their inner and outer body. Lastly, they tend to prefer beautiful body line. After the experience, all participants became interested in the body line and preferred to build a beautiful body line with correct postures. The most significant effect of Balletfit was the body line. Therefore, the experience of Balletfit develops the inner and outer body awareness and also can be consider to effect the change of the body shape. Balletfit will become a satisfying exercise for modern people, who desire a beautiful, healthy body.

• Journal of Intelligence and Information Systems
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• v.8 no.2
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• pp.205-227
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• 2002

Our study is focused on a multiple-agent system to provide efficient collaborative work by automating the conference calling process with the help of intelligent agents. Automating the meeting scheduling requires a careful consideration of the individual official schedule as well as the privacy and personal preferences. Therefore, the automation of conference calling needs the distributed processing task where a separate calendar management process is associated for increasing the reliability and inherent parallelism. This paper describes in detail the design and implementation issues of a multiple-agent system for conference calling that allows the convener and participants to minimize their efforts in creating a meeting. Our system is based on the client-sewer model. In the sewer side, a scheduling agent, a negotiating agent, a personal information managing agent, a group information managing agent, a session managing agent, and a coordinating agent are operating. In the client side, an interface agent, a media agent, and a collaborating agent are operating. Agents use a standardized knowledge manipulation language to communicate amongst themselves. Communicating through a standardized knowledge manipulation language allows the system to overcome heterogeneity which is one of the most important problems in communication among agents for distributed collaborative computing. The agents of our system propose the dates on which as many participants as possible are available to attend the conference using the forward chaining algorithm and the back propagation network algorithm.

• Archives of design research
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• v.12 no.4
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• pp.61-68
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• 1999

Most of the time, developers spend their energy to analyze the main function of the system or make source codes. As a result, they can not consider user interface on their own system and this is true in most programmer's world. But we want to consider the design concept in developing mechanism. In this case we have to upgrade the legacy system which maintaining the transmission system using the copper cables, and add the transmission system using the optical fiber cables. Therefore we design the user interface make easy for end users who are using the maintaining system on copper cables not to confuse the new system which include optical fibers. Especially, we are consider the developing model of design policy and real user to make easy to use new system. In this paper we will describe the instance to adapt the design concept on Broadband Access Network Operation Support System.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.53-61
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• 2008

Public Key Broadcast Encryption (PKBE) allows a sender to distribute a message to a changing set of users over an insecure channel. PKBE schemes should be able to dynamically exclude (i.e., revoke) a certain subset of users from decrypting a ciphertext, so that only remaining users can decrypt the ciphertext. Another important requirement is for the scheme to be forward-secrecy. A forward-secure PKBE (fs-PKBE) enables each user to update his private key periodically. This updated private key prevents an adversary from obtain the private key for certain past period, which property is particularly needed for pay-TV systems. In this paper, we present a fs-PKBE scheme where both ciphertexts and private keys are of $O(\sqrt{n})$ size. Our PKBE construction is based on Boneh-Boyen-Goh's hierarchical identity-based encryption scheme. To provide the forward-secrecy with our PKBE scheme, we again use the delegation mechanism for lower level identities, introduced in the BBG scheme. We prove chosen ciphertext security of the proposed scheme under the Bilinear Diffie-Hellman Exponent assumption without random oracles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.383-389
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• 2017

This study assesses the necessity of popular music instructor training, and promotes the establishment of popular music educational institutions and certification related to applied music education. Popular music has profound influence in popular culture, and is gradually diversifying. However, successful singers predominantly remain mostly boy/girl performance groups lacking musical skills. This study posits the cause of this problem is the absence of popular music instructor training systems, and suggests solutions. Currently, Korea's popular music lacks a public education system that teaches students effectively. Also, popular music is acknowledged as field-oriented, and isn't recognized for its academic value. Lastly, the lack of professional instructor training system in higher educational institutions creates challenges in fostering effective teachers. Solutions to these problems include establishing dedicated educational institutions and establishing certification programs. Implementing these solutions will provide significant positive effects in developing globalization for the currently stagnant K-pop industry. In addition, these solutions would contribute to the stabilization of the popular music industry, enhancing the image, and developing the popular music industry in general. In conclusion, this study promotes the popular music industry development by influencing and promoting awareness of music professionals, not just applied music students.