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Article type: Cover
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Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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Article type: Index
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Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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Yasuhiro INAZUMI, Taichi ISOGAI, Toshiyuki YOSHIDA, Yoshinori SAKAI, Y ...
Article type: Article
Session ID: NIM2001-47
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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The final objective of this research is to develop a transcoder which converts the original video bitstream in such a way that the resultant perceptual quality is maximized. However, the optimal framerate highly depends on video contents and/or a given bitrate. This paper thus discribes a determination method of the optimal framerate based some feature values of a target video. The experimental results have showen that the optimal framerate can be well estimated for closed data.
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Hirotsugu Okura, Masami Kato, Shuji Tasaka
Article type: Article
Session ID: NIM2001-48
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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This report discusses various problems caused by delay and loss of BIFS packets in MPEG-4 multimedia communication over QoS non-guaranteed networks such as the Internet. We focus on BIFS packet loss and clarify the problems. We point out that abnormal output due to the loss does not return to normal even if the network condition recovers. We then propose a compensation method for the loss, which transmit the latest whole scene composed by the sender. We also identify problems in installing the method into the MPEG-4 reference software Im1.
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Taro YOKOYAMA, Shuji TASAKA, Yutaka ISHIBASHI
Article type: Article
Session ID: NIM2001-49
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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This report studies improvement of the media synchronization quality for stored audio-video transmission in a wireless LAN environment with handover. The authors previously showed the effectiveness of the VTR(Virtual-Time Rendering)media synchronization algorithm in the handover environment. However, the algorithm could not recover packet loss during the handover. In order to recover the packet loss, we adopt a retransmission-based error recovery scheme for continuous media(RVTR)and demonstrate its effectiveness by experimunt. We make handover by walking in a specific area for our experimental system. We have confirmed that RVTR with dynamic resolution control of video can improve the voice quality.
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Tatsuya Yamazaki, Noriyuki Sato, Shigeru Fukunaga
Article type: Article
Session ID: NIM2001-50
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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A real-time MPEG-4 video transmission system is used to conduct subjective video quality measurements. In the measurements, three video QoS(Quality of Service)parameters, that is, the frame size, frame rate, and quantization scale change, then the double stimulus continuous quality scale method is used to obtain the subjective test scores from the testees. This report provides the experimental results and discusses on the correlation between the QoS parameters and the user assessment, which might be useful for user-adaptive QoS control in video streaming service.
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Akihiko Tsuno, Kenichi Mase, Naoyuki Karasawa
Article type: Article
Session ID: NIM2001-51
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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In this report, we measured QoS data during several weeks using timeit and wget for a set of mirror servers. We compared several server selection algorithms and found that performance of server selection can be improved using QoS statistics and real time QoS probing in the Internet. Furthermore, we investigate the performance of server selection algorithm by changing parameters QoS statistics.
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Abdulkhalig Bilhaj, Yuichiro Toyama, Kenichi Mase, Masakazu Sengoku
Article type: Article
Session ID: NIM2001-52
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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This paper introduces a new network technique for the admission control decisions. The basic idea is to probe the network to detect and control the level of congestions on both VoIP stream directions. We use two different classes in which data packets are given higher priority than the probe ones. This technique evaluates the packet loss rate by using edge-to-edge QoS measurements. The network model contains of a set of PBX, VoIP gateways, routers, and transmission links connecting VoIP gateways and routers. We illustrate the performance of our approach with a set of simulation experiments using a wide range of conditions, capable of guiding the admission control for the VoIP network..
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Yoshihiro ITO, Katsuyuki YAMAZAKI, Shun-ichi IISAKU, Tohru ASAMI
Article type: Article
Session ID: NIM2001-53
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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Demands for a new service that guarantees regular quality of service are increasing as the Internet expands. To provide such a service, many carriers are considering introducing a new technology, Multi-Protocol Label Switching(MPLS). In this paper, we discuss a method to configure MPLS Label Switching Router using a MPLS Management Server.
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Kiyoshi Tomaru, Yutaka Ishibashi, Shuji Tasaka
Article type: Article
Session ID: NIM2001-54
Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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This report proposes an adaptive QoS control scheme for live video and voice traffic in distributed virtual environments where live video and voice streams are output in a 3-D virtual space. According to the network load, CPU load, and importance of each media object, the proposed scheme carries out traffic control, CPU load control, media synchronization control, and retransmission control. Also, since several of control schemes which are employed for the four types of control can be used for plural types of control, we study how to perform them together. In addition, we illustrate the effectiveness of the adaptive QoS control scheme by experiment.
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Article type: Appendix
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Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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Article type: Cover
Pages
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Published: February 22, 2001
Released on J-STAGE: June 23, 2017
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