• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.352-360
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• 2010

Supporting user perceptual QoE-guaranteed IP-based multimedia service such as IPTV and Mobile IPTV, we represent an efficient QoE-aware transport stream assessment schemes to apply realtime mobile IPTV's contents distorted by various network errors such as bandwidth, delay, jitter, and packet loss. This paper proposes in detail an efficient matching and QoE-aware measurement methods. The brightness of the digitized contents per each frames of transport streams is used and applied to reduced-reference method. The hybrid video quality metric is designed by QoE-indicators such as blur, block, edge busyness, and color error. We compare original with processed source to evaluate them in a high precision degree of accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.327-346
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• 2013

Researchers as well as network providers are increasingly interested in understanding how a network user's experience changes in relation to different quality of service (QoS) parameters, with many attempts being made to identify the general relationship between quality of experience (QoE) and QoS. Several relations in different function forms have been proposed. There are instances when this variety of proposed functions potentially results in one problem having completely dissimilar solutions at the same time. The question then is which function form is the one that can better explain this relationship. In this paper, three major existing quantitative relationships between QoE and QoS are investigated. After conducting a comprehensive comparative analysis between them, a new definition of QoE-QoS dependency appears. It then results in identifying a new mutual relationship between QoE and QoS. The newly proposed relationship improves the deficiency of previous QoE-QoS relationships along with solving the problem of diversity of simultaneous solutions for one problem.

• ETRI Journal
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• v.32 no.6
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• pp.843-853
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• 2010

A successful deployment of multimedia applications over wireless environments entails improving the quality of service (QoS), not only from a technical point of view, but also considering the quality of experience (QoE) from the final user's perception. Although objective QoE measure models avoid the difficulties of subjective surveys, subjective QoE assessments are essential to understand the way users evaluate the QoS. In this work, we study the effect of a wide range of parameters on the QoE of VVoIP applications in a real wireless scenario. Through a complete statistical analysis of users' ratings, we identify the following facts. Although the use of VVoIP in wireless networks does not yet represent an advantage for users, there are great expectations for all applications under study, and with greater popularity comes higher expectations. It is easier for respondents to identify good behavior than poor behavior. Whereas the respondents' frequency of Internet use does not impact on the scores, respondents' gender does. Finally, the most determining parameters of quality from a user's perspective were instability, video quality, voice distortion, usefulness, and graphical interface.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.18-30
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• 2015

As the speed of networks that subscribers can use has greatly increased, demand for high-quality broadcast content, such as from Internet Protocol Television (IPTV) and Video on Demand (VoD), is likewise increasing. Therefore, while broadcasters are increasing content and channels, they are striving to improve consumer quality of experience (QoE) to differentiate themselves from competitors, including by producing higher physical-quality content. Recently, subjective measurement methods have been internationally standardized as the most reliable approach for measuring and evaluating IPTV QoE. However, a majority of these methods are performed in experimental environments and are based on the extremely brief viewing period of approximately ten seconds using original reference videos. It is actually difficult to apply standard evaluation methods based on a ten-second viewing interval to assess real broadcast watching of IPTV or other services that involve a longer time (i.e., more than thirty minutes). In this paper, we therefore propose a method that accommodates actual viewing environments. Using the mean opinion score, we experimentally analyze the effects of evaluation interval changes under actual conditions in which IPTV service is provided. In addition, we propose improvements by applying the results into actual live broadcast IPTV service and by analyzing consumer service QoE.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2513-2530
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• 2021

With the fast development of information and communication technologies, video streaming services and applications are increasing rapidly. However, the network condition is volatile. In order to provide users with better quality of service, it is necessary to develop an accurate and low-complexity model for Quality of Experience (QoE) prediction of time-varying video. Memory effects refer to the psychological influence factor of historical experience, which can be taken into account to improve the accuracy of QoE evaluation. In this paper, we design subjective experiments to explore the impact of Short-Term Memory (STM) on QoE. The experimental results show that the user's real-time QoE is influenced by the duration of previous viewing experience and the expectations generated by STM. Furthermore, we propose analytical models to determine the relationship between intrinsic video quality, expectation and real-time QoE. The proposed models have better performance for real-time QoE prediction when the video is transmitted in a fluctuate network. The models are capable of providing more accurate guidance for improving the quality of video streaming services.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.161-162
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• 2012

본 논문에서는 주관적 3D quality of experience (QoE) 평가에 적합한 IACQE (Interactive Assistance Continuous Quality Evaluation) 방법을 제안한다. 이 방법은 크게 3D 평가 영상이 재생되는 디스플레이와 평가 도구사이의 device interaction, 평가 도구와 평가 참여자사이의 human interaction process로 구성된다. Device interaction process는 무선 네트워크 프로토콜 (WLAN and WiFi)을 통해 3D 디스플레를 동작시키는 서버와 평가 도구 사이의 정확한 동기화 및 평가결과 기록 등의 작업을 수행하며, human interaction process는 평가 도구로 사용하는 tablet-pc의 촉각, 시각, 청각적인 자극을 통해 기존의 주관적 3D QoE 평가에서 나타날 수 있는 문제점들을 최소화 한다.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.440-451
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• 2008

With the advent of IP-based multimedia service based on IP network, there is a rapidly increasing demand for IPTV. Unlike the previous coaxial cable based TV, IPTV provides a variety of convergence services based on IP newark. However, since the IPTV service quality is a lot affected by the network degradation such as packet loss and jitter, it may not be guaranteed. In this paper, we propose an objective measure for various degradations of IPTV-based videos considering subjective assessment. To this end, we first determine QoE(Quality of Experience) indicators, which can affect human visual perception. Then we develop the video quality metric for each QoE indicator. Subjective assessment based on MOS is conducted and used to construct mapping relationship between each measure and perceived visual quality. Experiments are performed on various videos to confirm the efficiency and robustness of the proposed method and show high correlation with subjective assessment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2464-2479
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• 2020

This paper presents a detailed subjective quality assessment for the ultra-high definition (UHD) videos having frame rates of 30fps and 60 fps. The subjective assessment is based on the ITU-R BT-500 recommendations, where double stimulus continuous quality scale (DSCQS-type II) test is performed for the evaluation of the perceived quality of the user's in terms of differential mean opinion score (DMOS). Encoding of the UHD videos by opting encoders i.e. H.264/AVC, H.265/HEVC, and VP9 at five different quantization parameter (QP) levels is done to investigate the perceived user's quality of experience (QoE) given as DMOS. Moreover, the encoding efficiency as the encoding time for each encoder and qualitative performance by employing full-reference (FR) quality metrics are presented in this work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.592-606
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• 2011

Currently, the development of multimedia communication has progressed so rapidly that the video program service has become a requirement for ordinary customers. The quality of experience (QoE) for the visual signal is of the fundamental importance for numerous image and video processing applications, where the goal of video quality assessment (VQA) is to automatically measure the quality of the visual signal in agreement with the human judgment of the video quality. Considering the codec effect to the video quality, in this paper an efficient non-reference (NR) VQA algorithm is proposed which estimates the video quality (VQ) only by utilizing the distorted video signal at the destination. The VQA feature vectors (FVs) which have high relationships with the subjective quality of the distorted video are investigated, and a hybrid NR VQA (HNRVQA) function is established by considering the multiple FVs. The simulation results, testing on the SDTV programming provided by VCEG Phase I, show that the proposed algorithm can represent the VQ accurately, and it can be used to replace the subjective VQA to measure the quality of the video signal automatically at the destinations.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.331-338
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• 2019

Video services over Internet is getting important. Since the service quality of the video service provided by streaming over Internet may be degraded, the quality assessment and management are very important. Currently the objective method based on the measured values of parameters is being widely used for video services. The subjective assessment, however, is more ideal in that the quality that is experienced by human. This paper, therefore, proposes a subjective quality management scheme for video service in a mobile environment that overcomes the limitations of the subjective method. The proposed scheme is expected to contribute to implement a more efficient quality management system for video services in a mobile environment.