• Journal of KIISE:Software and Applications
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• v.30 no.7_8
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• pp.599-609
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• 2003

Video abstraction is a process to pick up some important shots on a video, while the important shots might vary on the persons subjectivity. Previous works on video abstraction use only one low level feature to choose an important shot. This thesis proposes an abstraction scheme that selects a set of shots which simultaneously satisfies the desired features(or objective functions) of a good abstraction. Since the complexity of the computation to find a set of shots which maximizes the sum of object function values is $0({2^n})$, the proposed .scheme uses a simulated annealing based searching method to find the suboptimal value within a short period of time. Upon the experimental results on various videos, we could argue that the proposed abstraction scheme could produce a reasonable video abstraction. The proposed abstraction scheme used to build a digital video library.

• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.368-379
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• 2010

As high-definition video is broadly used in various system such as broadcast system and digital camcorder the proper method in order to improve the quality of high-definition video is needed. In this paper, we propose an efficient method to improve color and contrast of high-definition video. In order to apply the image enhancement method to high-definition video, scale-down video of high-definition video is used and the parameter for image enhancement method is computed from small size video. To enhance the color of high-definition video, we apply color constancy method. First, we separate the video into several scenes by cut detection method. Then, we apply color constancy to each scene with same parameter. To improve the contrast of high-definition video, we use union of original image and histogram equalized image, and weight is calculated based on sorting of histogram bins. Finally, the performance of proposed method is demonstrated in experiment section.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.11-27
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• 2005

To date, most identity-based key agreement protocols are based on a single PKG (Private Key Generator) environment. In 2002, Chen and Kudla proposed an identity-based key agreement protocol for a multiple PKG environment, where each PKG shares identical system parameters but possesses distinct master key. However, it is more realistic to assume that each PKG uses different system parameters including the PKG's master key. In this paper, we propose a new two party key agreement protocol between users belonging to different PKGs that do not share system parameters. We also extend this protocol to two types of tripartite key agreement protocols. We show that our two party protocol requires minimal amount of pairing computation for a multiple PKG environment and our tripartite protocol is more efficient than existing protocols. We also show that the proposed key agreement protocols satisfy every security requirements of key agreement protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.209-211
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• 2022

YouTube, a video platform used by millions of people worldwide, provides a rapidly growing video service. This study aims to understand the characteristics and cultural differences of each country using the Kaggle dataset, one of the public datasets, and to show the usefulness of the public dataset. For this purpose, we analyze data from 11 countries, 15 categories, and about 1.1 million trending videos. This study adopts Python to obtain the number of videos by category for data analysis, the selection period of videos rapidly increasing in popularity, and the ratio of unique videos. In the future, based on machine learning, we plan to research to help diagnose individual videos and establish channel operation plans and strategies by predicting the selection possibility and selection period based on machine learning.

• Journal of Digital Contents Society
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• v.16 no.2
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• pp.291-298
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• 2015

In a fast-paced information technology environment, consumption of video content is changing from one-way television viewing to VOD (Video on Demand) playing anywhere, anytime, on any device. This video-watching trend gives additional importance to videos with fine-speed-control, in addition to the strength of the digital video signal. Currently, many video players provide a fine-speed-control function which can speed up the video to skip a boring part, or slow it down to focus on an exciting scene. The audio information is just as important as the visual information for understanding the content of the speed-controlled video. Thus, a number of algorithms for fine-speed-control video-playing technologies have been proposed to solve the pitch distortion in the audio-processing area. In this study, well-known techniques for prosodic modification of speech signals, WSOLA (Waveform-Similarity-Based Overlap-Add), have been applied to analyze users' needs for fine-speed-control video playing. By surveying the users' preferred speeds on categorized video content and analyzing the results, this paper proposes that various fine-speed adjustments are needed to accommodate users' preferred video consumption.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.147-153
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• 2011

In this paper, we present a new video management technique using forward timeline to efficiently store and delete the videos on a local server. The proposed method is based on capturing the changing preference of the videos according to recentness, frequency, and playback length of the requested videos. For this purpose, we utilize the forward timeline which represents the time area within a number of predefined intervals. The local server periodically measures time popularity and request segment of all videos. Based on the measured data, time popularity and request segment, the local server calculates the mean time popularity and mean request segment of a video using forward timeline. Using mean time popularity and mean request segment of video, we estimate the ranking and allocated storage space of a video. The ranking represents the priority of deletion when the storage area of local server is running out of space and the allocated storage space means the maximum size of storage space to be allocated to a video. In addition, we propose an efficient storage space partitioning technique in order to stably store videos and present a time based free-up storage space technique using the expected variation of video data in order for avoiding the overflow on a local server in advance. The simulation results show that the proposed method performs better than other methods in terms of hit rate and number of deletion. Therefore, our video management technique for local server provides the lowest user start-up latency and the highest bandwidth saving significantly.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.349-357
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• 2012

The purpose of this study was to measure the thickness of the sinus lateral wall using cone-beam computed tomography (CBCT), and to find the most suitable vertical position for lateral window opening prior to sinus elevation. Fifty three patients requiring sinus elevation had CBCT scans acquired by CB MercuRay (Hitachi, Medico, Tokyo, Japan) from July, 2010 to June, 2012. The thickness of the sinus lateral wall was measured according to its vertical position against the sinus inferior border (SIB), and its mean was calculated through two repeated measurements. The thickness of the sinus lateral wall was more than 2 mm at 2 mm above the sinus inferior border (SIB+2), however, it was less than 2 mm at 3 mm above the sinus inferior border (SIB+3). In conclusion, it is recommended that the inferior border of lateral wall window be made 3 mm above the sinus inferior border during sinus elevation using the lateral approach considering the thickness of the sinus lateral wall.

• Resources Recycling
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• v.27 no.6
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• pp.44-52
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• 2018

In this study, copper was recovered from copper containing sludge by selectively controlling electro-refining process conditions in copper sulfate electrolyte solution. Electro-refining process was performed by LSV (Linear Sweep Voltammetry) result according to copper sulfate electrolyte solution concentration, applied current density, additive type and concentration. SEM (Scanning Electron Microscope) and PSA (Particle Size Analyzer) were used to analyze the shape and size of copper powder. In the 0.1 ~ 0.4 M copper sulfate electrolyte solution without organic additives, the copper powder size decreased as the applied current density became closer to the limiting current density and the copper powder size tended to decrease in 0.2 ~ 0.3 M copper sulfate electrolyte solution. In addition, when the shape and size of the copper powder were analyzed by adding various types and concentrations of organic additives to the previous experimental, fine spherical copper powder having the smallest size (nm) was obtained under the condition of cellulose type additive 2,000 ppm.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.21-24
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• 2007

3차원 컴퓨터 그래픽스에서는 3차원 모델의 표면이 유리나 거울과 같이 반사 특성을 갖는 경우, 반사 효과를 반영하여 렌더링(rendering)하게 된다. 3차원 모델에서 동영상이 물체 표면에 반사되는 경우, 반사 특성을 갖는 3차원 모델의 표면은 동영상의 변화에 따른 반사 영상이 표현되도록 해야 한다. 3차원 컴퓨터 그래픽스에서 사용하는 반사 모델을 이용하여 동영상의 반사 영상을 렌더링하게 되면 처리시간이 많이 걸리게 되므로 고성능 하드웨어의 지원이 필요하다. 본 논문에서는 3차원 컴퓨터그래픽스에서 3차원 모델에서 반사 특성을 갖는 표면에 동영상의 반사 영상을 고속으로 생성하는 방법을 제안한다.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.1029-1035
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• 2008

본 연구는 기존의 인터넷 및 웹 광고에 대한 연구들을 바탕으로 동영상 UCC 광고에 대한 소비자의 태도와 수용에 영향을 미치는 요인을 분석해 보고자 하였다. 웹 광고 모델에서 사용된 정보성, 오락성, 부정적 자극 이외에 유용성과 용이성, 개인사용자 특성, 플로우, 그리고 인센티브를 새로운 변인으로 추가하였다. 연구 결과에 따르면, 오락성, 부정적 자극, 유용성 및 용이성, 플로우는 동영상 UCC 광고에 유의한 영향을 미치는 것으로 나타났지만, 정보성, 개인사용자 특성, 그리고 인센티브는 그렇지 않은 것으로 나타났다. 플로우는 동영상 UCC 광고의 수용에도 직접적으로 영향을 미치는 것으로 나타났으며, 동영상 UCC 광고에 대한 태도는 수용에 유의한 영향을 미치는 것으로 나타났다.