• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.847-858
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• 2012

In this paper, we propose a mobile watermarking based on the distortion analysis of display-capture image in a smart phone. We compose a random sequence by utilizing the property of frequency band in the wavelet domain. Then we calculate the CCS (Coefficients Comparative Sum) using the block wavelet coefficients of selected subbands after the wavelet transformation and the random sequence and repeatedly embed a watermark using an insertion threshold for the watermark robustness. For correcting a distortion caused by the display-capture process, we adopt a frame at the outside of watermarked image, then we can equate a watermark synchronization by detecting the frame. And we can improve frame detection ratio by using an iteratively adaptive threshold. A proposed scheme embedded information of 206 bits into standard digital images and it shows an average about 41.42 dB in PSNR. In watermark extract experiments, a proposed scheme accurately recognizes the frame more than 97% in total captured images. Also in BER (Bit Error Ratio) of captured images, it shows about 3.73%, then it was improved more than 70%, compared with the Pramila's method.

• Journal of Korea Multimedia Society
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• v.11 no.1
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• pp.117-128
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• 2008

Recently, as the increase in interaction between the person and the person, the people plentifully use the business card to exchange personal information. So, the people have many business cards. Thus, the people are liable to lose the business cards and finding a wanted business card is very difficult in the huge business cards in offline. And, the people think the business card is a way, which can express individuality. So, the people want to have the business card, which has individuality. Thus, this paper proposes the card system, which is satisfied to solve many problems of the card system in offline and express individuality. The proposed business card system can produce various business cards and puts contents such as video, photo, voice into business cards via mobile devices in anywhere, anytime. Also, this business card system follows the vCard format, which is a file format standard for personal data interchange. Finally, we provide with content-based business card retrieval using video and photo inserted into business cards. Thus, this paper proposes the hybrid business card system, which is satisfied to produce business cards expressed individuality and follows the vCard format.

• Journal of Korea Multimedia Society
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• v.13 no.3
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• pp.349-358
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• 2010

Adaptability is an important issue in video streaming over mobile environments, since the clients may request videos with great differences in their workload. In this paper, we propose the issues in limited bandwidth scheduling for efficient MPEG-4 video stream transmission over a mobile or wireless network. In the phase of admission control, the amount of bandwidth allocated to serve a video request is the mean bandwidth requirement of its requested video. The dynamic allocation of bandwidth in the phase of scheduling depends on the playback buffer levels of the clients with an objective to make it more adaptive to the playback situation of individual clients. In the proposed RTA scheduling protocol, more bandwidth may be allocated temporarily to the client whose buffer level is low. By employing the buffer level based scheduling policy, this protocol attempts to maximize the real-time performance of individual playback while minimizing the impact of transient overloading. Extensive simulation experiments have been performed to investigate the performance characteristics of the RTA protocol as comparing with BSBA protocol. This RTA protocol shows the better performance by transferring more frames than BSBA protocol.Computer simulations reveals that the standard deviation of the bit rate error of the proposed scheme is 50% less than that of the conventional method.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.802-816
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• 2010

To create gesture from a new text input is an important problem in computer games and virtual reality. Recently, there is increasing interest in gesture stylization to imitate the gestures of celebrities, such as announcer. However, no attempt has been made so far to stylize a gestures using emotion such as happiness and sadness. Previous researches have not focused on real-time algorithm. In this paper, we present a system to automatically make gesture animation from SMS text and stylize the gesture from emotion. A key feature of this system is a real-time algorithm to combine gestures with emotion. Because the system's platform is a mobile phone, we distribute much works on the server and client. Therefore, the system guarantees real-time performance of 15 or more frames per second. At first, we extract words to express feelings and its corresponding gesture from Disney video and model the gesture statistically. And then, we introduce the theory of Laban Movement Analysis to combine gesture and emotion. In order to evaluate our system, we analyze user survey responses.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.267-275
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• 2003

The development of the mobile communication has been enlarged gradually and has been changed voice centered services into data centered ones supporting Internet to provide various kinds of mobile internet services. Researches for data transmission have been achieved actively lot the effective approachment of web in the mobile terminal. The users using mobile communication are increasing for its easy handcarried and movement and the information in internet based upon wire communication has been changed into mobile communication fast. The development of mobile internet requires various mobile contents using mobile internet at any time and at any place due to rapid enhance of network capacity and mobile internet according to network expansion. To accept these needs, there are many difficult problems that contents must be remade according to various terminal features and the develoument costs much. To solve these problems, this paper has the pun)me that contents of Web documents are changed and processed through XML palter and design new mobile contents system, providing mobile services rapidly and obtaining the charge reduction result with the enhance of contents development to the shortening of a development Period.

• Journal of Korea Multimedia Society
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• v.16 no.1
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• pp.56-66
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• 2013

In MANET, the frequent movement of nodes causes the dynamic network topology changes. Therefore, it is required that the routing protocol should be very stable to effectively respond the changes of the network changes. Moreover, the existing cluster-based routing protocol, that is the hybrid approach, has routing delay due to the re-electing of the cluster header. In addition, the routing table of CBRP has all only one hop distant neighbor nodes. PCBRP, proposed in this paper, ties two clusters in one paired cluster to make longer radius. Then the headers of the paired cluster manage and operate corresponding member nodes. In the current CBRP, when the cluster header leaves out the cluster, the delay, due to the re-electing a header, should be occurred. However, in PCBRP, another cluster header of the paired cluster plays the role instead of the left cluster header. This method reduces the routing delay. Concurrently, PCBRP reduces the delay when they route nodes in the paired cluster internally.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.488-497
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• 2016

Given the potential of mobile applications to create new learning opportunities beyond the prevalent use of digital textbooks and Internet lectures, this study aims to derive types and themes of mobile application content that can be effectively integrated with the school curricula. Twenty primary school teachers participated in this study that examines teachers' perceptions about the advantages and disadvantages of printed and digital textbooks' modality, the advantages and disadvantages of mobile learning, and the themes relevant to develop mobile applications. Findings indicate that it is necessary to develop activity-centered applications for vertical use rather than theme-centered applications for horizontal use. In addition, while most ideas derived from teachers center on multimedia access, there was lack of ideas that leverage the affordances of mobile devices for collaborative interaction and location-awareness. Lastly, to promote the diffusion of mobile learning in school environments, this study suggests the need to overcome teachers' epistemology that perceives mobilization against inquiry activities.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.68-76
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• 2002

Multicast in mobile host has the problem of hast mobility, multicast decision, triangle routing, tunnel convergence, implosion of retransmission, and bandwidth waste. In particular, the bandwidth waste in radio is a definite factor that decreases transmission rate. To solve the problems, this paper proposes a new multicast transmission protocol called FIM(Forward Error Correction Integrated Multicast), which supports reliable packet recovery mechanism by integrating If Mobility Support for the host mobility, IGMP(Interned Group Management Protocol) for the group management, and DVMRP(Distance Vector Multicast Routing Protocol) for the multicast routing, and it also uses FEC and the local recovery method based on receiver. The performance measurement is performed by dividing the losses into the homogeneous independent loss, the heterogeneous independent loss, and the shared source link loss model.. The result shows that the performances improves in proportion to the size of local areal group when the size of transmission group exceeds designated size. This indicates FIM is effective in the environment where there are much of data and many receivers in the mobile host.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.895-900
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• 2009

This study focused on user centered design methodology on mobile service design, Especially we designed business supporting service for sale persons with heavy mobile uses in their works. We used contextual inquiry interview to understand user's work context and mobile usage. The findings are applied to the service concept, And information architecture, interaction design, GUI design is followed. As a result of design research, Post widget service is designed for instant information organization and functional relationship. And Memory box widget service is designed for business network management and contextual findability. Those services are developed for widget design on touch based phone platform.

• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.527-534
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• 2009

Almost every mobile phone supports MMS to send and receive multimedia messages among users. MMS is suitable for different types of mobile phones and effectively operates in wireless environments. So the mobile content delivery method using MMS can be efficient. However, there would be some problems if a mobile service provider tries to deliver mobile content to subscribers by using the existing MMS. In this paper, we propose an improved data transmission and control scheme for MMS. Our scheme assists mobile service providers to deliver mobile contents easily by modifying the MMS system software. By using our scheme, mobile service providers are able to manage mobile contents stored in mobile devices. Therefore, they can provide various services such as mobile daily news service, automatic software upgrade service, mobile advertising service, etc. We verify the possibility of the proposed scheme through simulation.