Pitch extraction and voiced/unvoiced detection of speech by cross-coupling multi-layered neural network with feedback architecture

Pitch frequency is one of the most important voice characteristics, and its accurate extraction is important not only in speech analysis and synthesis, but also in speech coding, speech recognition, speaker recognition, and the like. Existing methods of improving extraction accuracy include waveform processing, correlative processing, and spectral processing. This paper describes the use of a neural network to extract pitch from voice features delivered from the bandpass filter pairs (BPFPs) proposed by Fonda et al. Three types of multi-layered neural networks able to learn time-continuity and high accuracy discrimination functions and have a recurrent structure are tested. The cross-coupling multi-layered neural network with feedback architecture gives the best improvement over conventional neural networks, and exhibits superior ability for learning time continuity of pitch and U/V information. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(9): 48–58, 1997

帯域フィルタ対バンクとリカレントニューラルネットワークを用いた音声ピッチ抽出に関する研究

取得学位：博士(工学)，学位授与番号：博甲第513号，学位授与年月日：平成14年3月22日,学位授与年：200

MPEG-TFRCP: Video Transfer with TCP-friendly Rate Control Protocol

As the use of real-time multimedia applications increases, bandwidth available to TCP connections is oppressed by "greedy" UDP traffic and their performance extremely deteriorates. In order that both TCP and UDP sessions fairly co-exist in the Internet, UDP sessions should properly react against congestion as TCP. In this work, we implement a "TCP-friendly" rate control mechanism suitable to video applications and investigate its applicability to a real system through observation of the video quality at the receiver. It is shown through our experimental system that we can achieve high-quality and stable video transfer while fairly sharing the network bandwidth with TCP by applying our rate control at a control interval of 16 or 32 times as long as RTT

MPEG-4 Video Transfer with TCP-Friendly Rate Control

It is widely known that network bandwidth is easily monopolized by distributed multimedia applications due to their greedy UDP traffic. In this paper, we propose TCP-friendly MPEG-4 video transfer methods which enable realtime video applications to fairly shares the bandwidth with conventional TCP data applications. We consider how video applications should regulate video quality to adjust video rate to the desired sending rate which is determined by TCPfriendly rate control algorithm. Carelessly applying TCP-friendly rate variation to the video application would seriously degrade the application-level QoS. For example, the control interval should be long enough to avoid the fluctuation of video quality caused by too frequent rate control. However, popular TCP-friendly rate control algorithms recommend that a non-TCP session regulates its sending rate more than once a RTT. Through simulation experiments, it is shown that highquality and stable video transfer can be accomplished by our proposed methods

Dynamic Quality Adaptation Mechanisms for TCP-Friendly MPEG-4 Video Transfer

When a considerable amount of UDP traffic is injected into the Internet by distributed multimedia applications, the Internet is easily driven congested. Consequently, bandwidth available to TCP connections is oppressed and their performance significantly deteriorates. In order that both multimedia applications and TCP-based ones fairly co-exist in the Internet, it becomes increasingly important to consider the inter-protocol fairness