• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.124-131
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• 2003

In this paper, we propose a Progressive scalable video coding algorithm using frequency weighting in the DCT domain. Since the human visual system (HVS) can be modeled as a nonlinear point transformation, called the modulation transfer function (MTF), we tan use the frequency weighting matrix to enhance the video image quality. We change this frequency weighting matrix into the frequency shift matrix to apply to the bit-plane coding method for the fine granular scalable (FGS) video coding We also define a new error metric JNDE (just noticeable difference) to measure the perceptual image quality in terms of human vision.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.61-68
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• 2015

Mobile ad hoc networks (MANETs) are self-organized dynamic networks populated by mobile nodes. This paper presents the improved cross-layer approach to complement the recent works for video transmission services on MANET. We use a statistical design of experiment and analysis in order to investigate interactions between major factors of each layer effectively with minimizing ns-3 simulation run time. The proposed cross-layer approach considers MANET protocol layers (i.e., physical, network and transmission layers) and an application layer (i.e., a video encoder) as factors simultaneously. In addition, the approach defines an objective video quality metric as a response variable. The result of this paper can be applicable as a preliminary research to design an optimized video transmission application which has ability to adjust controllable factors to dynamic uncontrollable factors.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.81-88
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• 2004

In this paper, we propose a new objective quality assessment method considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2118-2135
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• 2012

With the rapid development of heterogeneous emerging wireless technologies and numerous types of mobile devices, the need to support robust mobile video streaming based on the seamless handover in Future Internet is growing. To support the seamless handover, several IP-based mobility management protocols such as Mobile IPv6 (MIPv6), fast handover for the MIPv6 (FMIPv6), Hierarchical MIPv6 (HMIPv6) and Proxy Mobile IPv6 (PMIPv6) were developed. However, MIPv6 depreciates the Quality-of-Service (QoS) and FMIPv6 is not robust for the video services in heterogeneous emerging wireless networks when the Mobile Node (MN) may move to another visited network in contrast with its anticipation. In Future Internet, the possibility of mobile video service failure is more increased because mobile users consisting of multiple wireless network interfaces (WNICs) can frequently change the access networks according to their mobility in heterogeneous wireless access networks such as 3Generation (3G), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMax) and Bluetooth co-existed. And in this environment, seamless mobility is coupled according to user preferences, enabling mobile users to be "Always Best Connected" (ABC) so that Quality of Experience is optimised and maintained. Even though HMIPv6 and PMIPv6 are proposed for the location management, handover latency enhancement, they still have limit of local mobility region. In this paper, we propose a robust mobile video streaming in Heterogeneous Emerging Wireless Systems. In the proposed scheme, the MN selects the best-according to an appropriate metric-wireless technology for a robust video streaming service among all wireless technologies by reducing the handover latency and initiation time when handover may fail. Through performance evaluation, we show that our scheme provides more robust mechanism than other schemes.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.513-522
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• 2016

We propose a mechanism for monitoring load in quality of service (QoS)-enabled wireless networks and show how it can be used for network management as well as for dynamic pricing. Mobile network traffic, especially video, has grown exponentially over the last few years and it is anticipated that this trend will continue into the future. Driving factors include the availability of new affordable, smart devices, such as smart-phones and tablets, together with the expectation of high quality user experience for video as one would obtain at home. Although new technologies such as long term evolution (LTE) are expected to help satisfy this demand, the fact is that several other mechanisms will be needed to manage overload and congestion in the network. Therefore, the efficient management of the expected huge data traffic demands is critical if operators are to maintain acceptable service quality while making a profit. In the current work, we address this issue by first investigating how the network load can be accurately monitored and then we show how this load metric can then be used to provide creative pricing plans. In addition, we describe its applications to features like traffic offloading and user satisfaction tracking.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.327-334
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• 2009

The tiled-display system provides a high resolution display which can be used in different applications in co-working area. The systems used in the co-working field usually save the user logs, and these log information not only makes the maintenance of the tiled-display system easier, but also can be used to check the progress of the co-working. There are three main steps in the proposed tiled display log recorder. The first step is to capture the screen shots of the tiles and send them for merging. The second step is to merge the captured tile images to form a single screen shot of the tiled-display. The final step is to encode the merged tile images to make a compressed video stream. This video stream could be stored for the logs of co-working or be streamed to remote users. Since there could be differences in capturing time of tile images, the quality of merged tiled-display could be degraded. This paper proposes a time stamp-based metric to evaluate the quality of the video stream, and a merging algorithm that could upgrade the quality of the video stream with respect to the proposed quality metrics.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.717-724
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• 2009

The most important issue for successful deployment of IPTV service is the service quality. In this paper, we first choose critical quality metrics belonging to each layer of IPTV service transmission architecture and then analyze the relation between the quality parameters. For this purpose, we implement a test network that emulates the most practical environment in which IPTV service is provided and repeat measurements on the test network for the chosen metrics. Based on the analysis result, it is shown that packet losses have greater effect on the video quality of IPTV service comparing to delay and jitter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.216-233
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• 2013

Conventional optimization designs of wireless networks mainly focus on spectral efficiency (SE) as a performance metric. However, as diverse media services are emerging, a green wireless network, which not only meets the quality of experience (QoE) requirements for users and also improves energy efficiency (EE), is the most appropriate solution. In this paper, we firstly propose the unit QoE per Watt, which is termed QoE efficiency (QEE), as a user-oriented metric to evaluate EE for wireless networks. We then analyze which is the kind of wireless resource given priority to use under different scenarios to obtain an acceptable QEE. Particularly, power, delay and data-rate related to QoE are separately addressed for several typical services, such as file download, video stream and web browsing services. Next, the fundamental tradeoffs are investigated between QEE and SE for wireless networks. Our analytical results are helpful for network design and optimization to strike a good balance between the users perceived QoE and energy consumption.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.81-84
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• 2006

다양한 멀티미디어 사용 환경 조건에 적합한 컨텐츠를 제공하기 위해서는 다양한 소비 환경을 반영할 수 있는 스케일러블 비디오의 제공이 필요하다. 이러한 스케일러블 비디오의 경우, 다양한 조합의 프레임 율, SNR, 공간해상도를 가지는 비디오가 가능하므로 사용자에 게 최적의 품질을 제공하는 조합을 결정해야 할 필요가 있다. 따라서 본 논문에서는 프레임율, SNR, 공간해상도 그리고 영상의 모션 속도에 따라 변동할 수 있는 영상 품질을 나타낼 수 있는 새로운 영상 품질 메트릭을 주관적 평가를 통하여 제안한다. 제안한 품질 메트릭은 주관적 품질평가 선호도와의 상관계수(correlation coefficient)가 PSNR과 주관적 품질평가 점수와의 상관계수 평균값에 비해 높은 값을 보였다. 본 논문에서 제안한 품질 메트릭은 다양한 조합의 부호화 조건에 따른 품질측정이 가능하여 제한적인 멀티미디어 소비환경에서 최적의 부호화 조건을 결정할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.474-475
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• 2021

The accuracy of real-time video analysis system based on 3D skeleton data highly depends on the quality of data. This study proposes a methodology to distinguish noise in 3D skeleton frames using Intersection Over Union (IOU) method. IOU is metric that tells how similar two rectangles (i.e., boxes). Simply, the method decides a frame as noise or not by comparing the frame with a set of valid frames. Our proposed method distinguished noise in 3D skeleton frames with the accuracy of 99%. According to the result, our proposed method can be used to track noise in 3D skeleton frames.