# Dr Frank Langbein

Senior Lecturer

School of Computer Science and Informatics

*Email:*- langbeinfc@cardiff.ac.uk
*Telephone:*- +44 (0)29 2087 0110
*Location:*- S/2.18B, Queen's Buildings - South Building, 5 The Parade, Newport Road, Cardiff, CF24 3AA

- Media commentator
- Available for postgraduate supervision

I am a senior lecturer in Computer Science at Cardiff University leading the Quantum Technologies and Engineering (QuTeE) research priority area and a member of Visual Computing research group. My research interests lie in the areas of control, machine learning, geometry and modelling applied in quantum technologies, computer-aided design and visual computing. See my web site Ex Tenebris Scientia for recent results and full details.

### Education

- 2003: PhD (Computer Science, Geometric Modelling), Cardiff University, UK.
- 1998: Diploma in Mathematics (comparable to MSc), Stuttgart University, Germany.

### Career Overview

- 1999 - present: Cardiff University School of Computer Science and Informatics
- 1994 - 1999: Stuttgart University, Mathematical Institute A & B
- 1991 - 1996: Ower fo small computer business

### Professional memberships

- American Mathematical Society
- IEEE

### 2018

- Jonckheere, E., Schirmer, S. and Langbein, F. 2018. Jonckheere-Terpstra test for nonclassical error versus log-sensitivity relationship of quantum spin network controllers. International Journal of Robust and Nonlinear Control 28(6), pp. 2383-2403. (10.1002/rnc.4022)
- Rahimi, N.et al. 2018. CAD Model simplification error estimation for electrostatics problems. Siam Journal on Scientific Computing 40(1), pp. B196-B227. (10.1137/16M1078641)
- Schirmer, S.et al. 2018. Robustness of energy landscape control for spin networks under decoherence. Presented at: IEEE 57th Annual Conference on Decision and Control (CDC), Fontainebleau in Miami Beach, FL, USA, December 17-19, 2018.

### 2017

- Thorpe, B.et al. 2017. Monte Carlo simulations of spin transport in a strained nanoscale InGaAs field effect transistor. Journal of Applied Physics 122(22), article number: 223903. (10.1063/1.4994148)
- Schirmer, S. G., Jonckheere, E. and Langbein, F. 2017. Design of feedback control laws for information transfer in spintronics networks. IEEE Transactions on Automatic Control 63(8), pp. 2523-2536. (10.1109/TAC.2017.2777187)
- O'Neil, S.et al. 2017. Sensitivity and robustness of quantum spin-1/2 rings to parameter uncertainty. Presented at: IEEE 56th Annual Conference on Decision and Control (CDC) 2017, Melbourne, Australia, 12-15 December 2017IEEE 56th Annual Conference on Decision and Control (CDC) 2017.
- Jonckheere, E. A., Schirmer, S. G. and Langbein, F. C. 2017. Structured singular value analysis for spintronics network information transfer control. IEEE Transactions on Automatic Control 62(12), pp. 6568-6574. (10.1109/TAC.2017.2714623)
- Thorpe, B.et al. 2017. Spin recovery in the 25nm gate length InGaAs field effect transistore. Presented at: International Workshop on Computational Nanotechnology, Windermere, UK, 6-9 June 2017Proc. International Workshop on Computational Nanotechnology. pp. 168-169.

### 2015

- Langbein, F. C., Schirmer, S. and Jonckheere, E. 2015. Time optimal information transfer in spintronics networks. Presented at: 2015 IEEE 54th Annual Conference on Decision and Control (CDC), Osaka, Japan, 15-18 December 20152015 IEEE 54th Annual Conference on Decision and Control (CDC) December 15-18, 2015. Osaka, Japan. IEEE pp. 6454-6459.
- Niu, Z.et al. 2015. Rapidly finding CAD features using database optimization. Computer-Aided Design 69, pp. 35-50. (10.1016/j.cad.2015.08.001)
- Jonckheere, E., Langbein, F. C. and Schirmer, S. G. 2015. Information transfer fidelity in spin networks and ring-based quantum. Quantum Information Processing 14(12), pp. 4751-4785. (10.1007/s11128-015-1136-4)
- Schirmer, S. G. and Langbein, F. C. 2015. Ubiquitous problem of learning system parameters for dissipative two-level quantum systems: Fourier analysis versus Bayesian estimation. Physical Review A 91(2), article number: 22125. (10.1103/PhysRevA.91.022125)
- Niu, Z.et al. 2015. Applying database optimization technologies to feature recognition in CAD. Computer-aided design and applications 12(3), pp. 373-382. (10.1080/16864360.2014.981468)

### 2014

- Jonckheere, E., Langbein, F. and Schirmer, S. 2014. Quantum networks: anti-core of spin chains. Quantum Information Processing 13(7), pp. 1607-1637. (10.1007/s11128-014-0755-5)
- Schirmer, S. and Langbein, F. C. 2014. Characterization and control of quantum spin chains and rings. Presented at: 2014 6th International Symposium on Communications, Control and Signal Processing (ISCCSP), Athens, 21 - 23 May 2014Communications, Control and Signal Processing (ISCCSP), 2014 6th International Symposium on. IEEE pp. 615-619., (10.1109/ISCCSP.2014.6877950)

### 2013

- Quinn, J. A.et al. 2013. Generalized anisotropic stratified surface sampling. IEEE Transactions on Visualization and Computer Graphics 19(7), pp. 1143-1157. (10.1109/TVCG.2012.305)
- Tam, G. K. L.et al. 2013. Registration of 3D point clouds and meshes: A survey from rigid to nonrigid. IEEE Transactions on Visualization and Computer Graphics 19(7), pp. 1199-1217. (10.1109/TVCG.2012.310)
- Wu, J.et al. 2013. Making bas-reliefs from photographs of human faces. Computer-Aided Design 45(3), pp. 671-682. (10.1016/j.cad.2012.11.002)

### 2012

- Quinn, J. A.et al. 2012. Improved initialisation for centroidal Voronoi tessellation and optimal Delaunay triangulation. Computer-Aided Design 44(11), pp. 1062-1071. (10.1016/j.cad.2012.05.002)
- Jonckheere, E., Langbein, F. C. and Schirmer, S. G. 2012. Curvature of quantum rings. Presented at: 5th International Symposium on Communications Control and Signal Processing (ISCCSP, Rome, Italy, 2-4 May 2012Communications Control and Signal Processing (ISCCSP), 2012 5th International Symposium on. IEEE pp. 1-6., (10.1109/ISCCSP.2012.6217863)

### 2011

- Jonckheere, E., Schirmer, S. G. and Langbein, F. C. 2011. Geometry and curvature of spin networks. Presented at: 2011 IEEE Multi-Conference on Systems and Control, Denver, CO, USA, 28-30 September 20112011 IEEE International Conference on Control Applications (CCA). Los Alamitos, CA: IEEE pp. 786-791., (10.1109/CCA.2011.6044395)

### 2010

- Li, M., Langbein, F. C. and Martin, R. R. 2010. Detecting design intent in approximate CAD models using symmetry. Computer-Aided Design 42(3), pp. 183-201. (10.1016/j.cad.2009.10.001)
- Li, W., Martin, R. R. and Langbein, F. C. 2010. Merging and smoothing machining boundaries on cutter location surfaces. Presented at: 14th ACM Symposium on Solid and Physical Modeling, Haifa, Israel, 1-3 September 2010 Presented at Keyser, J. and Kim, M. eds.Proceedings of the 14th ACM Symposium on Solid and Physical Modeling, 1-3 September 2010, Haifa, Israel. New York: ACM pp. 165-170., (10.1145/1839778.1839803)
- Schirmer, S. G. and Langbein, F. C. 2010. Quantum system identification: Hamiltonian estimation using spectral and Bayesian analysis. Presented at: 4th International Symposium on Communications, Control and Signal Processing (ISCCSP 2010), Limassol, Cyprus, 3-5 March 2010 Presented at Constantinides, A. G. and Mitra, S. K. eds.Proceedings of the 4th International Symposium on Communications, Control and Signal Processing (ISCCSP) 2010. Los Alamitos, CA: IEEE, (10.1109/ISCCSP.2010.5463437)

### 2009

- Sun, X.et al. 2009. Random walks for feature-preserving mesh denoising. Computer Aided Geometric Design 25(7), pp. 437-456. (10.1016/j.cagd.2007.12.008)
- Li, W., Martin, R. R. and Langbein, F. C. 2009. Molds for meshes: computing smooth parting lines and undercut removal. IEEE Transactions on Automation Science and Engineering 6(3), pp. 423-432. (10.1109/TASE.2009.2021324)
- Sun, X.et al. 2009. Noise analysis and synthesis for 3D laser depth scanners. Graphical Models 71(2), pp. 34-48. (10.1016/j.gmod.2008.12.002)
- Sun, X.et al. 2009. Bas-relief generation using adaptive histogram equalization. IEEE Transactions on Visualization and Computer Graphics 15(4), pp. 642-653. (10.1109/TVCG.2009.21)

### 2008

- Sun, X.et al. 2008. Noise in 3D laser range scanner data. Presented at: 10th International Conference on Shape Modeling and Applications, Stony Brook, NY, USA, 4-6 June 2008 Presented at Michela Spagnuolo, M., Cohen-Or;, D. and Gu, X. D. G. eds.Shape Modeling and Applications, 2008. SMI 2008. IEEE International Conference. Los Alamitos, CA: IEEE Computer Society pp. 37-45., (10.1109/SMI.2008.4547945)
- Langbein, F. C., Li, M. and Martin, R. R. 2008. A comment on 'constructing regularity feature trees for solid models'. Lecture Notes in Computer Science 4975, pp. 603. (10.1007/978-3-540-79246-8_53)
- Li, M., Langbein, F. C. and Martin, R. R. 2008. Detecting approximate symmetries of discrete point subsets. Computer-Aided Design 40(1), pp. 76-93. (10.1016/j.cad.2007.06.007)

### 2007

- Sun, X.et al. 2007. Fast and Effective Feature-Preserving Mesh Denoising. IEEE Transactions on Visualization and Computer Graphics 13(5), pp. 925-938. (10.1109/TVCG.2007.1065)
- Quinn, J. A., Langbein, F. C. and Martin, R. R. 2007. Low-discrepancy point sampling of meshes for rendering. Presented at: Eurographics/IEEE VGTC Symposium on Point-based graphics 2007, Prague, Czech Republic, 2-3 September 2007Point-based graphics 2007 : Eurographics/IEEE VGTC Symposium proceedings, Prague, Czech Republic, September 2-3, 2007. Aire-la-Ville, Switzerland: Eurographics pp. 19-28., (10.2312/SPBG/SPBG07/019-028)
- Sun, X.et al. 2007. Random walks for mesh denoising. Presented at: SPM 2007: ACM Symposium on Solid and Physical Modeling, Beijing, China, 4-6 June 2007Proceedings, SPM 2007 : ACM Symposium on Solid and Physical Modeling : Beijing, China, June 04-06, 2007. New York, USA: Association for Computing Machinery pp. 11-22., (10.1145/1236246.1236252)
- Li, W., Martin, R. R. and Langbein, F. C. 2007. Generating smooth parting lines for mold design for meshes. Presented at: ACM Symposium on Solid and Physical Modeling, Beijing, China, 4-6 June 2007Proceedings, SPM 2007: ACM Symposium on Solid and Physical Modeling : Beijing, China, June 04-06, 2007. New York, USA: Association for Computing Machinery pp. 193-204., (10.1145/1236246.1236274)
- Liu, S.et al. 2007. Segmenting periodic reliefs on triangle meshes. Presented at: 12th IMA International Conference, Sheffield, UK, 4-6 September 2007Mathematics of surfaces XII : 12th IMA international conference, Sheffield, UK, September 4-6, 2007 : proceedings. Lecture notes in computer science Vol. 4647. Berlin, Germany: Springer pp. 290-306., (10.1007/978-3-540-73843-5_18)
- Li, M., Langbein, F. C. and Martin, R. R. 2007. Detecting approximate incomplete symmetries in discrete point sets. Presented at: ACM Symposium on Solid and Physical Modeling, Beijing, China, 4-6 June 2007Proceedings, SPM 2007 : ACM Symposium on Solid and Physical Modeling : Beijing, China, June 04-06, 2007. New York, USA: Association for Computing Machinery pp. 335-340., (10.1145/1236246.1236294)
- Liu, S.et al. 2007. Segmenting geometric reliefs from textured background surfaces. Computer-aided design and applications 4(5), pp. 565-583.
- Liu, S.et al. 2007. Background surface estimation for reverse engineering of reliefs. International Journal of CAD/CAM 7(1), pp. 1-17.

### 2006

- Liu, S.et al. 2006. Segmenting reliefs on triangle meshes. Presented at: SPM 2006: ACM Symposium on Solid and Physical Modeling, Cardiff, UK, 6-8 June 2006Proceedings, SPM 2006 : ACM Symposium on Solid and Physical Modeling : Cardiff, Wales, United Kingdom, June 06-08, 2006, Vol. SPM06. New York, USA: Association for Computing Machinery pp. 7-16., (10.1145/1128888.1128890)
- Li, M., Langbein, F. C. and Martin, R. R. 2006. Constructing regularity feature trees for solid models. Presented at: Geometric Modeling and Processing (GMP 2006), Pittsburgh, PA, USA, 26-28 July 2006 Presented at Kim, M. S. and Shimada, K. eds.Geometric Modeling and Processing-GMP 2006. Lecture notes in computer science Vol. 4077. Berlin-Heidelberg: Springer Verlag pp. 267-286., (10.1007/11802914_19)
- Quinn, J. A.et al. 2006. Density-controlled sampling of parametric surfaces using adaptive space-filling curves. Presented at: Geometric Modeling and Processing (GMP 2006), Pittsburgh, PA, USA, 26-28 July 2006 Presented at Kim, M. and Shimada, K. eds.Geometric Modeling and Processing - GMP 2006. Lecture notes in computer science Vol. 4077. Berlin-Heidelberg: Springer Verlag pp. 465-484., (10.1007/11802914_33)

### 2004

- Langbein, F. C., Marshall, A. D. and Martin, R. R. 2004. Choosing Consistent Constraints for Beautification of Reverse Engineered Geometric Models. Computer-Aided Design 36(3), pp. 261-278. (10.1016/S0010-4485(03)00108-8)
- Gao, C. H.et al. 2004. Local topological beautification of reverse engineered models. Computer-Aided Design 36(13), pp. 1337-1355. (10.1016/j.cad.2004.02.004)
- Gao, C.et al. 2004. Partial approximate symmetry detection of geometric model. Materials Science Forum 471/2, pp. 702-706. (10.4028/www.scientific.net/MSF.471-472.702)
- Langbein, F. C.et al. 2004. Topological and geometric beautification of reverse engineered geometric models. Presented at: 9th ACM Symposium on Solid Modeling and Applications, Genoa, Italy, 9-11 June 2004 Presented at Fellner, D. W. et al. eds.Solid Modeling 2004. Aire- la- Ville, Switzerland: Eurographics Association pp. 255-260.

### 2003

- Gao, C.et al. 2003. Approximate congruence detection of model features for reverse engineering. Presented at: Shape Modeling International Conference 2003, 12-15 May 2003Proceedings of the Shape Modeling International Conference 2003. IEEE pp. 69-77., (10.1109/SMI.2003.1199603)

### 2002

- Langbein, F. C., Marshall, A. D. and Martin, R. R. 2002. Numerical methods for beautification of reverse engineered geometric models. Presented at: Geometric Modeling and Processing, Wako, Saitama, Japan, 10-12 July 2002Proceedings of Geometric Modeling and Processing. IEEE pp. 159-168., (10.1109/GMAP.2002.1027507)

### 2001

- Langbein, F. C.et al. 2001. Approximate Geometric Regularities. International Journal of Shape Modeling 7(2), pp. 129-162. (10.1142/S0218654301000096)
- Mills, B. I.et al. 2001. Approximate Symmetry Detection for Reverse Engineering. Presented at: Proceedings of the 6th ACM Symposium on Solid Modeling and Applications. , (10.1145/376957.376985)
- Langbein, F. C.et al. 2001. Finding approximate shape regularities for reverse engineering. Journal of Computing and Information Science in Engineering 1(4), pp. 282-290. (10.1115/1.1430232)
- Langbein, F. C.et al. 2001. Finding approximate shape regularities in reverse engineered solid models bounded by simple surfaces. Presented at: ACM Symposium on Solid and Physical Modeling, Ann Arbor, MI, USA, 4-8 June 2001 Presented at Anderson, D. C. ed.Proceedings of the sixth ACM symposium on Solid modeling and applications (SMA '01). New York: ACM pp. 206-215., (10.1145/376957.376981)
- Langbein, F. C.et al. 2001. Recognizing geometric patterns for beautification of reconstructed solid models. Presented at: SMI 2001 International Conference on Shape Modeling and Applications, Genova, Italy, 7-11 May 2001Proceedings of the SMI 2001 International Conference on Shape Modeling and Applications. IEEE pp. 10-19., (10.1109/SMA.2001.923370)

My research interests lie in the areas of control, machine learning, geometry and modelling applied in quantum technologies, computer-aided design and visual computing. I am working on controlling, modelling, indentifying and simluating quantum systems, with applications in spin dymamics for spintronics, networking and magnetic resonance imaging and spectroscopy. My work further encompasses geometric and solid modelling, processing of meshes, curves and surfaces, pattern recognition, graphics, and computational geometry. Special interests include point-based modelling, design intent of geometric models, approximate symmetries and reverse engineering geometric models.