• Journal of The Korean Association of Information Education
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• v.16 no.3
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• pp.275-282
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• 2012

Existing web based learning system provides various instruction paths. However, learners are provided with the same instruction content with little consideration of each learner's learning style. Therefore, Current Web based learning is lacking as a system that encourages individual learning, by failing to provide for proper instruction methods for each learner. This prototype system can find the most effective way of learning for each learner by analyzing a learner's learning. It also provides content based on the most effective instruction method for the learner taking into consideration learning style. Especially, this proposed adaptive learning system supporting dynamic link by learning style by evaluation for each steps of leaning process.

• Journal of KIISE
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• v.43 no.7
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• pp.827-833
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• 2016

HTTP Adaptive Streaming (HAS) is a technique that adapts its video quality to network conditions for providing Quality of Experience. In the HAS approach, a video content is encoded at multiple bitrates and the encoded video content is divided into several video segments. A HAS player estimates the network bandwidth and adjusts the video bitrate based on estimated bandwidth. However, the segment scheduler in the conventional HAS player requests video segments periodically without considering TCP. If the waiting duration for the next segment request is quite long, the TCP connection can be initialized and it restarts slow-start. Slow-start causes the reduction in TCP throughput and consequentially leads to low-quality video streaming. In this study, we propose a TCP-aware segment scheduling scheme to improve performance of HAS service. The proposed scheme adjusts request time for the next video request to prevent initialization of TCP connection and also considers the point of scheduling time. The simulation proves that our scheme improves the Quality of Service of the HAS service without buffer underflow issue.

• Journal of Broadcast Engineering
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• v.27 no.4
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• pp.527-537
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• 2022

As multimedia contents demand and supply increase, internet traffic around the world increases. Several standardization groups are striving to establish more efficient compression standards to mitigate the problem. In particular, research to introduce deep learning technology into compression standards is actively underway. Despite the fact that deep learning-based technologies show high performance, they suffer from the domain gap problem when test video sequences have different characteristics of training video sequences. To this end, several methods have been made to introduce content-adaptive deep video compression. In this paper, we will look into these methods by three aspects: codec information-aware methods, model selection methods, and information signaling methods.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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• pp.83-97
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• 2013

This study was carried out to suggest an experimental base in selecting the drought resistance of plants. Adopting the natural drought method, this paper studies the drought resistance of 12 kinds of ground cover plants. focusing on analyzing the changes of relative water content on leaf, relative electric conductivity and chlorophyll content in 12 kinds of plants, and and the relation between soil water content under drought stress. The drought resistance of the plants were subject to laboratory and rooftop drought resistance treatments. The Logistic model of nonlinear regression analysis was used to evaluate the lethal time that were predicted with the range of 10.4~30.1d on roof top, and 19.5~39.0d on hothouse. The result shows that with the increase of stress time, relative water content and chlorophyll content on leaf were in a downward trend; the relative electric conductivity was upward tendency. Among 12 species of ground cover plants, exclude Pulsatilla koreana, Ainsliaea acerifolia were selected for rooftop plants because they showed resist drought strongly and took adaptive ability.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.529-538
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• 2014

This study was conducted as an need analysis through close and open semi-structured surveys, in order to identify the adaptive elements of the adaptive e-learning system. The study was conducted on students majoring computer education in teacher's college. In terms of the process of the need analysis, Rossett Model was applied. For the research method, responses on the open questionnaire were analyzed. In terms of the analysis method, coding was used to extract the theme of the content, and through the constant comparison method, categorizing took place. As the element that offers adaption in the adaptive learning system, it escapes from the existing learning style, and recognized the importance of providing adaptability for different elements such as the learner's level, learning objectives, and learning contents. Especially, An instructional model was identified as an important element that helps reach rationality as well as efficiently conduct the learning objectives.

• Journal of The Korean Association of Information Education
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• v.17 no.4
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• pp.383-391
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• 2013

This study developed an adaptive instruction system for individual learning. We applied Gregorc's learning style to support the adaption. This proposed Instruction system provides instruction content based on a more effective instruction method that takes into consideration the learner's individual learning style. We applied Gregorc's learning style to create a clear treatment of differing learning styles. Proposed adaptive instruction system was applied to college students studying computer learning. A t-test indicated that our proposed adaptive instruction system resulted in positive effects in an overall style comparison. In addition, our Abstract-Sequential learning style indicated the most effective results while the Abstract-Random learning style indicated no difference between the experimental and comparative groups in each style analysis for Gregorc's learning style.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1061-1065
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• 2004

The knowledge-based society of the 21st century requires effective education and learning methods in each professional field because the development of human resource determines its competence more than any other factors. It is highly desirable to develop an intelligent tutoring system, which meets ever increasing demands of education and learning. Such a system should be adaptive to each individual learner's demands as well as the continuously changing state of the learning process, thus enabling the effective education. The development of a learning environment based on learner modeling is necessary in order to be adaptive to individual learning variants. An intelligent learning environment is being developed targeting the heritage education, which is able to provide a customized and refined learning guide by storing the content of interactions between the system and the learner, analyzing the correlations in learning situations, and inferring the learning preference from the learner's learning history. This paper proposes a heritage learning system of Bulguksa temple, integrating the ontology-based learner modeling and the learning preference which considers perception styles, input and processing methods, and understanding process of information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.308-324
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• 2018

HTTP adaptive streaming (HAS) is a promising technology for delivering video content over the Internet. HAS-based video streaming solutions rely on bandwidth estimation to select the appropriate video bitrate. Video streaming solutions that consider network conditions provide users with seamless video playback. However, when multiple clients compete for a common bottleneck link, conventional bandwidth estimation schemes that consider only one client overestimate the network bandwidth due to the ON-OFF traffic pattern. The bandwidth overestimation can cause Quality of Experience (QoE) degradation, such as unnecessary changes in video quality, and unfairness of video quality. In this paper, we propose a client-side bandwidth estimation scheme to obtain a better QoE of HAS in the multiple-client environment. The proposed scheme differentiates the client buffer status according to the buffer occupancy, and then estimates the available network bandwidth based on the buffer status and segment throughput. We evaluate the performance of HAS implemented in the ns-3 network simulator. Simulation results show that compared with the conventional schemes, the proposed scheme can enhance the QoE.

• ETRI Journal
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• v.38 no.5
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• pp.885-895
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• 2016

The lowest power mode (passive-standby mode) was proposed for reducing the power consumption of set-top boxes in a standby state when not receiving content. However, low-power set-top boxes equipped with the lowest power mode have been rarely commercialized because of their low-quality user experience. In the lowest power mode, they deactivates almost all of operational modules and processes, and thus require dozens of seconds for activation latency (that is, the latency for activating all modules of the set-top boxes in a standby state). They are not even updated in a standby state because they deactivate their network interfaces in a standby state. This paper proposes an adaptive standby mode scheduling method for improving the user experience of such boxes. Set-top boxes using the proposed method can analyze the activation pattern and find the frequently used time period (that is, when the set-top boxes are frequently activated). They prepare for their activation during this frequently used time period, thereby reducing the activation latency and enabling their update in a standby state.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.426-445
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• 2012

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.