Research Report. By An T. Le Oct 2005 Supervisor: Prof. Ravi Sankar, Ph.D. Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 1

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1 Research Report By An T. Le Oct 2005 Supervisor: Prof. Ravi Sankar, Ph.D. Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 1

2 Today s Topics 1. Voice over IP and IP PBX (part 2) SIP architecture Firewall, NAT and VoIP issues VoIP CODECs Demo: VoIP PBX system 2. Speech under Stress and applications Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 2

3 PART 1 Voice over IP and IP PBX (2) PBX and VoIP PBX VoIP materials VoIP Protocols VoIP QoS VoIP issues Demo Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 3

4 PBX (Private Branch exchange) Voice switching: local subscriber- local subscriber local subscriber- publics network remote subscriber Telephone Telephone Telephone PSTN Telephone Telephone PBX PBX Telephone Telephone Telephone Telephone Telephone Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 4

5 VoIP Voice-over-IP (VoIP) implementation enables users to carry voice traffic (telephone calls, faxes ) over an IP network. VoIP can have different type Gateways: IP, PSTN, PRI Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 5

6 * 8 # * 8 # Bay Networks SD Bay Networks SD Today s VoIP network IP Gateway- Router Gateway- Router LAN VoIP Server/ PBX VoIP Server/ PC IP Phone IP Phone PC PSTN gateway PSTN gateway PSTN Fax Analog Phone Analog Phone Fax Bay Networks BayStack 650 Wireless Access Point Bay Networks BayStack 650 Wireless Access Point Local Telephone Service C.O. C.O. Analog Phone Local Telephone Service Analog Phone Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 6

7 Why VoIP? Low cost phone calls? LAN-based PBX for cost reduction, flexibility, and new applications: Integrated voice/data LAN infrastructure (Merging of data/voice infrastructures) Integrated voice/data applications Open hardware/software platform Add-on services and unified messaging Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 7

8 VoIP materials Minimum IP Phone a phone and also a network device VoIP Server or just an IP switch Your PC could be both VoIP Server is an IP PBX Other Gateway converts media provided in one type of network to the format required for another type of network. In VoIP the Gateway to connect to PSTN could be an FXO port or T1/E1 (for PRI service) Call manager Call agent Other applications Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 8

9 VoIP Protocols Using Real-Time Transport Protocol/User Datagram Protocol/Internet Protocol (RTP/UDP/IP) as the protocol stack Most popular: SIP: Session Initiation Protocol (RFC 3261) Skinny: Skinny Client Control Protocol (SCCP) (by CISCO) Others: H.323 (ITU), SDP: Session Description Protocol Megaco H.248: Gateway Control Protocol MGCP: Media Gateway Control Protocol MIME: Multipurpose Internet Mail Extensions RVP over IP: Remote Voice Protocol Over IP Specification IAX (IAX2) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 9

10 CODEC - VOCODER In VoIP Coders are used for efficient bandwidth utilization. Different coding techniques for telephony and voice packet are standardized by the ITU-T in its G-series recommendations: G.723.1, G.729, G.729A etc. Other popular VoIP vocoders are G.711 and GSM Standard Description Bandwidth (Kbps) Coding delay G.711 PCM 64 1 µ s G.721 ADPCM 32,16,24, µs G.728 LD-CELP µ s G.729 CS-ACLEP ms G Muti-rate CELP 6.3/5.3 30ms Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 10

11 VoIP QoS again Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 11

12 IP PBX features Web interface Call ID Call forward Conference call Multi lines per IP phone Multi - destinations call Music on hold Directory Auto attendant Call waiting Voice mail Voice mail to Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 12

13 VoIP issues QoS Security Network conflicts High cost for IP phone Use high IP bandwidth Delay time, Echo (not a pure real-time voice) May have no emergency service such as 911 Need an IP service for a phone call Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 13

14 VoIP Security Service Deny of Service, free use of service Information Insert to the call Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 14

15 Firewall issue Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 15

16 Network Address Translator Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 16

17 NAT and Firewall issue Unknown public source Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 17

18 SIP (Session Initiation Protocol) Architecture Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 18

19 SIP with NAT and Firewall issue Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 19

20 Solution for NAT-SIP-Firewall The current proposals for solving NAT traversal are: Universal Plug and Play (UPnP) Simple Traversal of UDP Through Network Address Translation devices (STUN) Application Layer Gateway Manual Configuration Tunnel Techniques Automatic Channel Mapping (ACM) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 20

21 CODEC (Compression and DeCompression) Compress and De-Compress digitized voice stream is necessary. Digitized (Coder)+Compress = CO Decompress+D/A (Decoder)= DEC Coder/Decoder Waveform Modeling based (need power processor) Hybrid Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 21

22 Most popular CODEC is LPC based Predicted value x (n+d) x ˆ = H ( x, x... x 1 ) n+ d 0 1 n xˆ p n+ d = ( k = 1 a k ) x n k Error: e n+ d xn+ d xn+ d = ˆ QoS: d, interval, p-order Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 22

23 G.729 and GSM Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 23

24 DEMO IP PBX OS Platform Features Devices Management Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 24

25 PART 2 Speech under Stress and applications Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 25

26 CONTENT Classification of Speech under Stress Energy based and Frequency based analysis SUSAS: Stress Under Simulated and Actual Stress Database Applications Next steps Shorten: Simple lossless and near loss-less waveform compression Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 26

27 Classification of Speech Under Stress Human Speech Production Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 27

28 Stress makes change in Speech Local neuron take control the muscle Generate higher energy especially at the begin of word Use higher pitch (or lower) than normal Vibrated sound (tremor) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 28

29 Human Speech Production Human Speech model Tone controller Formant Excitation F1,t(n)+F2,t(n)+F3,t(n) Pitch (F 0,t (n)) Glottal Model Formant filters Radiation Model Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 29

30 Abnormal Speech Under stress, speech changes tones speech energy Vibration (tremor) Speech changes as unusual when: Yield Bored or tired Emphasis Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 30

31 Speech Under Stress Analysis Learning (from large samples) Features or patterns Feature set or pattern set? Energy-based Frequency based Classifier or Evaluator (yes/no or % in stress) How about Foreign Languages? Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 31

32 Speech Under Stress Classification Energy-based focus on Estimate vocal tract area profiles Acoustic tube area coefficient Mel-cepstral based parameters (MFCC) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 32

33 Mel-cepstral based parameters (MFCC) The typical parameters of a MFCC feature front end (e.g., 25 ms window, 10 ms frame rate) A compromise solution chosen to represent all phones, constraint of a fixed single set of parameters MFCC features may fail to capture many discriminative cues that have longer or shorter time spans. Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 33

34 Stress Classification features TEO- Teager Energy Operator A energy operator, with the supporting observation that hearing is the process of detecting the energy By Kaiser ψ [ x( t)] c ψ c = [ x( t)] d dt x( t) 2 d x( t) dt x( t) = [ x& ( t)] where is the Teager Energy Operator and x(t) is the single component of the continuous speech signal Discrete time form: x( t) & x( t) ψ c [ x( n)] 2 = x ( n) x( n + 1) x( n 1) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 34

35 TEO- Teager Energy Operator (cont.) TEO-FM-Var: Variation of FM component TEO-Auto-Env: Normalized TEO Autocorrelation Envelope Area TEO-CB-Auto-Env: Critical Band Based TEO Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 35

36 TEO- Teager Energy Operator (cont.) TEO-FM-Var: Variation of FM component Neural (left) Stressed (right) Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 36

37 TEO- Teager Energy Operator (cont.) TEO-Auto-Env: Normalized TEO Autocorrelation Envelope Area Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 37

38 TEO- Teager Energy Operator (cont.) TEO-CB-Auto-Env: Critical Band Based TEO Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 38

39 Evaluation Speech Under Stress Classification From Guojun Zhou, John H.L. Hansen and James F. Kaiser Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 39

40 SUSAS: Stress Under Simulated and Actual Stress Database Lead by John H.L. Hansen Frequency based created by the Robust Speech Processing Laboratory at Duke University under the direction of Professor John H. L. Hansen sponsored by the Air Force Research Laboratory. 32 speakers (13 female, 19 male), with ages ranging from 22 to 76 were employed to generate in excess of 16,000 utterances. contains several longer speech files from four Apache helicopter pilots. These helicopter speech files were transcribed by the Linguistic Data Consortium and are available via ftp. Use shorten format audio files Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 40

41 Practice based on SUSAS Database Read and convert shorten format to ASCII or other use with matlab Compare real paired samples Compared simulated samples Compare SUSAS and recorded samples Estimation Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 41

42 Example with word : change female 0.25 neutral 0.8 scream tired 0.2 others Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 42

43 Energy-based systems CVSA (Computerized Voice Stress Analyzer) DVSA (Digital voice Stress Analyzer) Digoenes Lantern Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 43

44 Frequency-based system TiPi 6.40 Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 44

45 Speech Under Stress Study Applications Stress detector Call center Customer support center Safety control Lie detector Still under develop Speech enhancement Lullaby Sound therapy Sound effect Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 45

46 Next steps Speech patterns for speech under stress Speech features set and learning algorithms- Classifier based on learning machine Behavior alarm for call center Lie detectors Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 46

47 Shorten: Simple lossless and near loss-less waveform compression The predictor is predicting a future value xn+d from n past values from x0 to xn-1 as following: (2.1) xˆ n+ d = H( x0, x1... xn 1) Where d is the prediction distance (interval) and H is the transform. There is a linear model for H as following [11,14]: p xˆ = ( a ) x (2.2) n+ d k = 1 Where p is the order of predictor, {ak} is the linear predictor coefficients And the error is k n k e n+ d xn+ d xn+ d = ˆ Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 47

48 The method Wiener Hoft we ve got all-pole Wiener- Hopf: r r r x x x (0) (1)... ( n) r r r xˆ( n x x x (1) (2)... (0) + d) = r x p 1 k = 0 w( k) x( n k) rx ( n) w(0) rx ( d) r x(0) w(1) rx ( d + 1) = ( n 1) w( n) rx ( d + n 1) where rx is the autocorrelation of X, w(0) w(n) is the coefficient and d is the predicted distance. Oct 28, 2005 An T. Le -USF- ICONS group - SUS ans VoIP 48

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