HWANG Jenq-Neng received his Ph.D. degree from the University of Southern California, USA. In the summer of 1989, Dr. HWANG joined the De- partment of Electrical Engineering of the Universi- ty of Washington in Seattl...HWANG Jenq-Neng received his Ph.D. degree from the University of Southern California, USA. In the summer of 1989, Dr. HWANG joined the De- partment of Electrical Engineering of the Universi- ty of Washington in Seattle, USA, where he has been promoted to Full Professor since 1999. He served as the Associate Chair for Research fi＇om 2003 to 2005, and from 2011-2015. He is current- ly the Associate Chair for Global Affairs and Inter- national Development in the EE Depamnent. Hehas written more than 330 journal papers, conference papers and book chapters in the areas of machine learning, muhimedia signal processing, and muhimedia system integration and networking, including an au- thored textbook on ＂Multimedia Networking： from Theory to Practice,＂ published by Cambridge University Press. Dr. HWANG has close work- ing relationship with the industry on muhimedia signal processing and nmltimedia networking.展开更多
With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable ...With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.展开更多
Reusing test cases from existing test case library is quite common in the software testing field. Testing practice tells us that there is a strong relationship between the granularity of a function unit under testing ...Reusing test cases from existing test case library is quite common in the software testing field. Testing practice tells us that there is a strong relationship between the granularity of a function unit under testing and that of the test case. A function unit with small granularity usually results in the test cases with the same small granularity. Therefore a test case defined as the function point,i. e.,the smallest size function unit,was provided for the first time.Though test cases with smaller granularity usually have better reusability,the cost of accurately reusing and integrating such test cases is also higher. In order to balance the test case reusability and the cost of test case reuse,a novel test case reuse model based on the function point was proposed in this paper. In this model,a reusable test case for specification-based testing was defined and some reuse strategies and three formal reuse methods were given. Finally,the complete automatic software process was realized by a reusing generation tool. The new method has improved reuse accuracy,while greatly enhances the software productivity.展开更多
Multimedia data traffic occupies more than 70% of the Internet traffic and is still growing. On-demand video is already a major video content platform and private broadcast is getting more popular. In addition to this...Multimedia data traffic occupies more than 70% of the Internet traffic and is still growing. On-demand video is already a major video content platform and private broadcast is getting more popular. In addition to this, virtual reality （VR） and augmented reali- ty （AR） data traffic is increasing very fast. To provide the good quality of the multimediaservice, huge amount of resource is need- ed because users ＇ service experience is usually proportional to the video rates they can receive. Moreover, the variation of the bandwidth also affects to the users＇ experience, w-hile more users w-ant to use their mobile devices to see multimedia data by ac- cessing the network through wireless links, such as Long Term Evolution （LTE） and Wi-Fi. Therefore, better spectral efficiency during wireless transmission and video rate adaptation to provide better quality to users are in great demand. Multicast system is one of the technologies that can improve the spectral efficiency drastically, and Dynamic Adaptive Streaming over HTTP （DASH） is one of the most popular video rate adaptation platforms. In this paper, we investigate the state-of-the-art video multicast technol- ogies. LTE supports the multicast service through evolved Multimedia Broadcast Multicast Service （eMBMS） systems, and there are different algorithms to perform the video multicast along with adaptive video quality control. The algorithms include the proce- dure to decide the video rates, resource allocations, and user groupings. Moreover, we propose a novel approach to improve the quality of experience for DASH-VR video multicast systems.展开更多
文摘HWANG Jenq-Neng received his Ph.D. degree from the University of Southern California, USA. In the summer of 1989, Dr. HWANG joined the De- partment of Electrical Engineering of the Universi- ty of Washington in Seattle, USA, where he has been promoted to Full Professor since 1999. He served as the Associate Chair for Research fi＇om 2003 to 2005, and from 2011-2015. He is current- ly the Associate Chair for Global Affairs and Inter- national Development in the EE Depamnent. Hehas written more than 330 journal papers, conference papers and book chapters in the areas of machine learning, muhimedia signal processing, and muhimedia system integration and networking, including an au- thored textbook on ＂Multimedia Networking： from Theory to Practice,＂ published by Cambridge University Press. Dr. HWANG has close work- ing relationship with the industry on muhimedia signal processing and nmltimedia networking.
文摘With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.
基金National Natural Science Foundation of China(No.61262010)
文摘Reusing test cases from existing test case library is quite common in the software testing field. Testing practice tells us that there is a strong relationship between the granularity of a function unit under testing and that of the test case. A function unit with small granularity usually results in the test cases with the same small granularity. Therefore a test case defined as the function point,i. e.,the smallest size function unit,was provided for the first time.Though test cases with smaller granularity usually have better reusability,the cost of accurately reusing and integrating such test cases is also higher. In order to balance the test case reusability and the cost of test case reuse,a novel test case reuse model based on the function point was proposed in this paper. In this model,a reusable test case for specification-based testing was defined and some reuse strategies and three formal reuse methods were given. Finally,the complete automatic software process was realized by a reusing generation tool. The new method has improved reuse accuracy,while greatly enhances the software productivity.
文摘Multimedia data traffic occupies more than 70% of the Internet traffic and is still growing. On-demand video is already a major video content platform and private broadcast is getting more popular. In addition to this, virtual reality （VR） and augmented reali- ty （AR） data traffic is increasing very fast. To provide the good quality of the multimediaservice, huge amount of resource is need- ed because users ＇ service experience is usually proportional to the video rates they can receive. Moreover, the variation of the bandwidth also affects to the users＇ experience, w-hile more users w-ant to use their mobile devices to see multimedia data by ac- cessing the network through wireless links, such as Long Term Evolution （LTE） and Wi-Fi. Therefore, better spectral efficiency during wireless transmission and video rate adaptation to provide better quality to users are in great demand. Multicast system is one of the technologies that can improve the spectral efficiency drastically, and Dynamic Adaptive Streaming over HTTP （DASH） is one of the most popular video rate adaptation platforms. In this paper, we investigate the state-of-the-art video multicast technol- ogies. LTE supports the multicast service through evolved Multimedia Broadcast Multicast Service （eMBMS） systems, and there are different algorithms to perform the video multicast along with adaptive video quality control. The algorithms include the proce- dure to decide the video rates, resource allocations, and user groupings. Moreover, we propose a novel approach to improve the quality of experience for DASH-VR video multicast systems.
