• Journal of the Korean BIBLIA Society for library and Information Science
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• v.15 no.2
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• pp.97-115
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• 2004

The paper examined the concepts and features of content-based Image and Video retrieval systems. It then analyzed the retrieval performance of on five content_based retrieval systems in terms of usability and retrieval features. The results showed that the combination of content_based retrieval techniques and meta-data based retrieval will be able to improve the retrieval effectiveness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12A
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• pp.2085-2091
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• 2001

In lossy compression method, the transformed coefficients are quantized. This results in the quantization noise. The video image quality and bit rate is closely related with the quantization step. In this paper, we proposed a new quantization function for the improved performance. The DC value of each macroblock is compensated depending on the magnitude of DC quantization error. It is implemented very low bit-rate video coding, i.e., H.26L. The experimental result is useful when the object motion is not severe.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.749-750
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• 2006

TFRC is an equation-based rate control scheme originally developed for video transmission over wired networks. When applied to the wireless networks, it suffers from performance degradation. In this thesis, we propose an end-to-end loss discrimination algorithm to improve the performance of TFRC over wireless networks. The proposed WLD-TFRC scheme combines Spike and WLD(Wireless Loss Discount) algorithms to discriminate wireless loss from congestion loss, and to discount feedback loss event rate. Experimental results show that WLD-TFRC outperforms the original TFRC and effectively reduce the degradation of the video quality caused by the wireless link status.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1043-1053
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• 2012

In distributed video coding (DVC) systems, the complexity of encoders is greatly reduced by removing the motion estimation operations in encoders, since the correlation between frames is utilized in decoders. The transmission of parity bits is requested through the feedback channel, until the related errors are corrected to decode the Wyner-Ziv frames. The requirement to use the feedback channel limits the application of DVC systems. In this paper, we propose an efficient method to remove the feedback channel in DVC systems. First, a simple side information generation method is proposed to calculate the amount of parity bits in the encoder, and it is shown that the proposed method yields good performance with low complexity. Then, by calibrating the theoretical entropy with three parameters, we can calculate the amount of parity bits in the encoder and remove the feedback channel. Moreover, an adaptive method to determine quantization parameters for key frames is proposed. Extensive computer simulations show that the proposed method yields better performance than conventional methods.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.455-457
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• 2019

In this paper we study the effect of decomposed spatiotemporal convolutions for action recognition in videos. Our motivation emerges from the empirical observation that spatial convolution applied on solo frames of the video provide good performance in action recognition. In this research we empirically show the accuracy of factorized convolution on individual frames of video for action classification. We take 3D ResNet-18 as base line model for our experiment, factorize its 3D convolution to 2D (Spatial) and 1D (Temporal) convolution. We train the model from scratch using Kinetics video dataset. We then fine-tune the model on UCF-101 dataset and evaluate the performance. Our results show good accuracy similar to that of the state of the art algorithms on Kinetics and UCF-101 datasets.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.207-208
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• 2009

Peer-to-Peer (P2P) network has great potential on utilizing the network while reducing the server loads. Video on Demand (VoD) has become widely used since we can watch contents we like without having to download the overall file first. The mobile users may not need high quality of video; they only need good enough quality that can be played in the limited resource of physical device and network. So does with the devices with very limited network bandwidth. These issues emerge an idea of allowing Free-Rider in the P2P VoD system, where those low performance devices will only optimize the network utilization, affecting none to the performance of main system.

• Health Communication
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• v.13 no.2
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• pp.217-221
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• 2018

Background: There are practical difficulties to show exact clinical symptoms such as seizure to medical students at Clinical Performance Examination (CPX). We developed a new CPX case of child's seizure on video using smartphone. Methods: A total of 356 $4^{th}-year$ students of five universities in Daegue-Gyeongbuk and Gyeongnam area took the clinical skill examination from June $13^{th}$ to $17^{th}$ in 2016. Among them, 72 students took the new CPX case in June $15^{th}$ and 71 students filled out the questionnaire on whether the new CPX with smartphone video is helpful, authentic, difficult, and necessary for other CPX. All the questions were measured on 5-Likert scale. Results: Mean score of the new CPX was 57.1, lower than the mean scores of the other 11 CPX cases, 62.8. For the question "Smartphone videos helped to solve the problem", 45 students (63.4%) answered 'Very much'. For the question "Is it realistic compared to other questions?" 30 students (42.3%) and 25 students (35.2%) answered 'Very much' and 'Much'. For the question "Is it difficult compared with other questions?" 18 students (25.4%) and 26 students (36.6%) answered 'Very much' and 'Much'. As for the question "I would like to have more tests using smartphone video", 26 students (36.6%) answered 'So and so'. Conclusion: A majority of students responded that video presentation was helpful and authentic to figure out the CPX, whereas they assessed smartphone video was more difficult compared with other CPXs. Further, students were negative toward using smartphone video for the other CPXs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.101-110
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• 2011

With the deployment of broadband networking technology, many clients are enabled to receive various Video on Demand (VoD) services. To support many clients, the network should be designed by considering the following factors: viewer's waiting time, buffer requirement at each client, number of channel required for video delivery, and video segmentation complexity. Among the currently available VoD service approaches, the Polyharmonic and Staircase broadcasting approaches show best performance with respect to each viewer's waiting time and buffer requirement, respectively. However, these approaches have the problem of dividing a video into too many segments, which causes very many channels to be managed and used at a time. To overcome this problem, we propose Polyharmonic-Staircase-Staggered (PSS) broadcasting approach that uses the Polyharmonic and Staircase approaches for the head part transmission and the Staggered approach for the tail part transmission. It is simple and bandwidth efficient. The numerical results demonstrate that our approach shows viewer's waiting time is comparable to that in the Harmonic approach with a slight increase in the bandwidth requirement, and saves the buffer requirement by about 60\% compared to the Harmonic broadcasting approach by simply adjusting the video partitioning coefficient factor. More importantly, our approach shows the best performance in terms of the number of segments and the number of channels managed and used simultaneously, which is a critical factor in real operation of VoD services. Lastly, we present how to configure the system adaptively according to the video partitioning coefficient.

• ETRI Journal
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• v.39 no.4
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• pp.502-513
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• 2017

For video understanding, namely analyzing who did what in a video, actions along with objects are primary elements. Most studies on actions have handled recognition problems for a well-trimmed video and focused on enhancing their classification performance. However, action detection, including localization as well as recognition, is required because, in general, actions intersect in time and space. In addition, most studies have not considered extensibility for a newly added action that has been previously trained. Therefore, proposed in this paper is an extensible hierarchical method for detecting generic actions, which combine object movements and spatial relations between two objects, and inherited actions, which are determined by the related objects through an ontology and rule based methodology. The hierarchical design of the method enables it to detect any interactive actions based on the spatial relations between two objects. The method using object information achieves an F-measure of 90.27%. Moreover, this paper describes the extensibility of the method for a new action contained in a video from a video domain that is different from the dataset used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.95-101
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• 2005

In this paper, some performance characteristics of multimedia traffic for mobile ad-hoc networks is studied with simulations. Synthetic streaming video is considered as the multimedia traffic for MPEG-coded video in the simulation. The synthetic video stream is generated with a video stream generation algorithm. The algorithm generate VBR traffics for MPEG video streams with special predefined GOP(group of pictures) patterns that is consisted of a sequence of I(intra-coded), P(predicted-coded) and B(bidirectional-coded) frames. The synthetic VBR streams is transmitted through UDP protocol with on-demand mobile ad-hoc network routing protocols like as AODV and DSR. And performances for video streams through mobile ad-hoc networks is evaluated, the throughputs is compared between data and video traffics.