Research highlights

1. Research highlights • Framework for Traffic Analysis in Wireless Networks, first exact solution for outage in cellular networks • 1st paper on MC-CDMA • ICI mitigation in mobile OFDM • New Attacks on Watermarking • Detection theory applied to watermarking • Privacy in Biometrics

2. Research Highlight 1991:Framework for Traffic Analysis in Wireless Networks • Mathematical framework based on Laplace Transforms for the analysis of random access schemes (MAC ) for wireless networks (considering PHY) • Basic idea: • Rayleigh fading gives exponential pdf of power • Average performance = Laplace {performance | channel} • Interference power = sum of power of individual components • Average performance • Visibility, Impact, Results: • Vederprijs 1992, MSc Cum laude, PhD cum laude • Monograph published by Artech House (their 2nd book on Wireless) • More than 119 citations (+ 34 + 33 + 17 + 15 + 14 + 10 + ..) • Virtual Cellular Network: in Chinese cellular proposal

3. Code N N N S/P P/S Matrix I-FFT B C A DS-CDMA OFDM MC-CDMA Time Time Time + - + - + - + Frequency Frequency Frequency - - - + + - + - + - + - + Research Highlight 1993: 1st paper on MC-CDMA • Basic idea: • cascade CDMA and OFDM, or equivalently, • define spreading codes in the frequency domain • Advantages in simultaneous user separation in multipath channels • Impact: • Name and concept MC-CDMA proposed first in 1993 paper • Citations 405 + 37 + 38 + 26 + 20 • MC-CDMA has become a major research topic (85,300 Google hits) • MC-CDMA proposed in several standards (ETSI, IEEE 802) Credit also to Gerhard Fettweis

4. 50 120 Research Highlight 2002 - 2004:ICI mitigation in mobile OFDM • Basic idea • series expansion of temporal behavior of subcarriers allows simple modeling of Inter Carrier Interference • Extension of statistical propagation model: behavior for derivatives • Impact, Visibility • 2 IEEE Transactions papers (2004) • patent applications • Basis for solution implemented in two ICs: • 15 + 10 + 8 citations MMSE ICI canceller Conventional OFDM Credit also to Stan Baggen et al.

5. AWGN Image H-1 Watermark + H X MF H Watermark Research Highlight 1997: Detection theory applied to watermarking The basic idea • Watermarking is equivalent to the detection of weak signals in the presence of structure interference • Hollywood content is not AWGN  • Exploit structure (predictability) in the content Impact • Papers, 60 + 19 + 15 + .. citations • Basic patent granted on predictive filtering for WM detection • Applied in Watercast product “you have seen content with our invisible watermarks, which are detected 24/24 on 1000 tv stations, using algorithms based on this idea” Credit also to Ton Kalker

6. Set of watermarked images Yes Space of images Yes Yes Yes No No No Set of random images No No Research Highlight 1998:New Attacks on Watermarking • Basic Idea: • robustness of watermark requires contiguous decision regions, whereas confidentiality of the key would require scattered chaotic regions • Search for point on “the” decision threshold of WM detector • Then evaluate sensitivity to small perturbations, say, dimension by dimension • This strongly suggests the Conjecture: • Public-key watermarking can not exist • Impact • Patented countermeasures • IEEE Proceedings paper and IHW • Citations: 150 + 71 + 62 + 38

7. X F Y F(x) Y X fingerprint Research Highlight 2002:Privacy in Biometrics The issue with conventional biometry: • Biometric template data can be misused by dishonest verifiers • Someone who finds your passport can misuse your fingerprint • How to set up a public data base for biometric verification? Basic idea: • One-way functions (cf. password protection) can be used if(f!) biometric measurements are preconditioned by ‘helper data’ • Information theoretic proof that helper data reveal less than e, that is, I(W;X) < e  0) • Helper date does not need to affect reliability (FAR & FRR) Impact • leading theme for 10 fte project now at Philips Research, and project at universities. • Potential impact: passports that contain verification data for biometrics, without allowing misuse • Privacy protection even in public database with dishonest verifiers of fingerprint • Basis for PUF Research • Citations: 15 + 9 (since 2003) • Tuyls, Willems: “effective cryptographic key length = Shannon capacity of biometric measurement channel” X F(x) G(x,w) Y noise N Helper dataW Challenge

8. Curriculum vitae: Education • Masters: • Eindhoven University of Technology, The Netherlands • Ir., Cum Laude, December 1986 • PHD • Delft University of Technology, The Netherlands • Dr., Cum Laude, December 18, 1991 • Promoter Prof. Jens Arnbak

9. Curriculum vitae:Professional experience • Physics and Electronics Lab (FEL-TNO): radio propagation models for frequency and operations planning • 1987-1988: Research Scientist, on military service (ROAG) • Delft University of Technology: Teletraffic in wireless networks • 1988-1991: Universitair Docent (Asst. Prof.) • 1994: Universitair Hoofddocent (Assoc. Prof.) • The University of California at Berkeley: Wireless Multimedia Communication • 1992-1993: Assistant Professor • 1995-1998: Adjunct Asst. Professor • Nat.Lab. Philips Research, Eindhoven: Conditional access, Copy management, Watermarks, Biometrics till 2003, Communication Systems after 2002 • 1995-1998: (Senior) Research Scientist • 1998-2000: Principal Scientist • 2001-now: Department Head, Senior Director

10. Teaching experience • T.U. Delft • Transmission systems • U.C. Berkeley • Signal and Systems EECS 120, • Probability Theory EECS 226, started EECS 126, • Selected Topics in Communications EE 290i: Wireless Communication • Short Courses & Tutorials • U.C. Extension: Wireless Communication Networks • Philips CTT: Wireless Basics; Advanced wireless; RF Transceivers; CoCoSec (Security and DRM) • EESI; PATO; IPA; EIDMA; WIC; EPFL • Coaching of students in during internships, and MSc, PhD, postdocs • UC Berkeley; TU Delft; Philips Research • Freelance radio presenter • NOS, ROZ; various local radio stations; Internet webstation • Educational CD-ROM and Internet • Kluwer; Springer