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Christian Ringhofer

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School of Mathematical and Statistical Sciences
Emeritus Professor
Faculty,
School of Mathematical and Statistical Sciences Emeriti
Emeritus Professor
Faculty,
Biography: 

Christian Ringhofer works on models to design and optimize ensembles, using methods of statistical physics. This is a research field with a multitude of applications. Applications he is currently working on are:

  1. Design of the next generation of solar cells, based on thin films of non - crystalline materials. These devices promise to be more cost effective than the currently used technology.
  2. Design of insurance policies based on game theoretical principles. This allows the insurer as well as the client to predict their optimal choice of rates and plans.
  3. Optimizing the flow structure in highly complex production systems, such as semiconductor 'fabs'. This serves to react optimally to changes in demand.
  4. Description of highly integrated semiconductor devices, functioning on quantum mechanical principles. Future generations of chips require this theory for optimal design of performance.
CV
Binary Data Curriculum Vitae
Education: 

Ph.D. Technical University of Vienna, Austria 1981

Publications: 
  • Clemens Heitzinger · Christian Ringhofer. Hierarchies of transport equations for nanopores. Journal of Computational Electronics (2014).
  • Clemens Heitzinger and Christian Ringhofer. Multiscale modeling of fluctuations in stochastic elliptic PDE models of nanosensors. Communications in Mathematical Sciences (2014).
  • D. Guo, R. Akis, D. Brinkman, I. Sankin, T. Fang, D. Vasileska, and C. Ringhofer,. One-Dimensional Reaction-Diffusion Simulation of Cu Migration in Polycrystalline CdTe Solar Cells. PVSC 2014 IEEE 40th,, (2014).
  • R. Akis, D. Guo, D. Brinkman, I. Sankin, T. Fang, D. Vasileska, and C. Ringhofer. Extracting Cu diffusion parameters in polycrystalline CdTe. PVSC, 2014 IEEE 40th (2014).
  • Pierre Degond, Jian-Guo Liu, Christian Ringhofer. Evolution of the Distribution of Wealth in an Economic Environment Driven by Local Nash Equilibria. Journal of Statistical Physics (published online) http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s10... (2013).
  • Pierre Degond, Jian-Guo Liu, Christian Ringhofer. Large-Scale Dynamics of Mean-Field Games Driven by Local Nash Equilibria. Journal of Nonlinear Science (published online) http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s00... (2013).
  • M. Herty, C. Ringhofer:. Feedback controls for continuous priority models in supply chain management. Computational methods in applied mathematics, (2012).
  • S. G¨ottlich, M. Herty, C. Ringhofer and U. Ziegler:. Production Systems with Limited Repair Capacity. Optimization (2012).
  • Thomas Windbacher, Viktor Sverdlov, Siegfried Selberherr, Clemens Heitzinger, Norbert J. Mauser, Christian A. Ringhofer. Study of the Properties of Biotin-streptavidin Sensitive BioFETs. In proceeding of: BIODEVICES 2009 - Proceedings of the International Conference on Biomedical Electronics and Devices, Porto, Portugal, January 14-17(2009), appeared 2012 (2012).
  • Clemens Heitzinger, Christian Ringhofer:. A TRANSPORT EQUATION FOR CONFINED STRUCTURES DERIVED FROM THE BOLTZMANN EQUATION. Communications in Mathematical Sciences 9(3):829-857, 2011 (2011).
  • M. Herty, C. Ringhofer:. AVERAGED KINETIC MODELS FOR FLOWS ON UNSTRUCTURED NETWORKS. Kinetic and Related Models, 4(4) : 1081:1096, 2011. doi:10.3934/krm.2011.4.1081 (2011).
  • Ringhofer. Gave a series of 5 lectures in the Summer School for Applied Mathematics at Shanghai Jiao Tong University (SJTU),. (2011).
  • c. ringhofer. "A level set approach to modeling general service rules in supply chains". Communications in Mathematical Sciences (2010).
  • Clemens Heitzinger, Yang Liu, Norbert J. Mauser, Christian Ringhofer, and Robert W. Dutton. Calculation of fluctuations in boundary layers of nanowire field-effect biosensors. J. Computational and Theoretical Nanoscience (2010).
  • M. La Marca_ D. Armbruster, M. Herty C. Ringhofer_:. "Control of continuum models of production systems". IEEE Transactions on Automatic Control (2010).
  • A. Unver, C. Ringhofer, D. Armbruster. A HYPERBOLIC RELAXATION MODEL FOR PRODUCT FLOW IN COMPLEX PRODUCTION NETWORKS. AIMS J. DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS Supplement 2009 pp. 791-800, 2009 (2009).
  • S. Goettlich, M. Herty, C. Ringhofer:. "Time-dependent order and distribution policies in supply networks". proceeding of ECMI conference, London, GB, 2008 (2009).
  • C. Ringhofer, C. Heitzinger:. Multi - Scale Modeling and Simulation of Field-Effect Biosensors. Transactions of the Electrochemical Society (2008).
  • Christian Ringhofer, gerhard klimeck. Modeling and Simulation of Field-Effect Biosensors ({BioFETs}) and Their Deployment on the {nanoHUB}. Journal of Physics: Conference Series (Proc. BIRS Workshop (2008).
  • Clemens Heitzinger , Christian Ringhofer, Siegfried Selberherr. Investigations of the Potential Jump at the Surface of {BioFETs} Using a Multi-Scale Model. Proc. 211th Meeting of the Electrochemical Society (ECS) pp: 947ff (2008).
  • D Armbruster, P Degond, Christian Ringhofer. Kinetic and fluid models for supply chains supporting policy attibutes. Bulletin of the Inst. Math., Academica Sinica (2008).
  • C Heitzinger, Christian Ringhofer. An Effective Quantum Potential for Particle-Particle Interactions in Three-dimensional SemiconductorDevice Simulations. J. Comp. Electronics (2007).
  • C Heitzinger, Christian Ringhofer, S Ahmed, D Vasileska. 3D Monte Carlo Device Simulations Using an Effective Quantum Potential Including Electron Electron Interactions in press. J. Comp. Electronics (2007).
  • Christian Ringhofer, Clemens Heitzinger, Siegfried Selberherr. Finite Difference Solutions of the Nonlinear {Schrödinger} Equation and their Conservation of Physical Quantities. Communications in the Mathematical Sciences (2007).
  • Christian Ringhofer, P. Degond. STOCHASTIC DYNAMICS OF LONG SUPPLY CHAINS WITH RANDOM BREAKDOWNS. SIAM J. Applied Mathematics (2007).
  • J Bourgade, P Degondm-Mauser, Christian Ringhofer. Quantum Corrections to Semiclassical Transport in Nanoscale Devices Using Entropy Principles. Journal of Comp. Electronics (2007).
  • M Herty, Christian Ringhofer. Optimization For Supply Chain Models With Policies. PHYSICA A (2007).
  • Ringhofer, Christian, Heitzinger, Clemens, Selberherr, Siegfried. . ECS (2007).
  • C Jungemann, A Pham, B Meinerzhagen, Christian Ringhofer, M Boellhofer. Stable discretization of the Boltzmann equation based on spherical harmonics, box integration and a maximum entropy dissipation principle. Journal Appl. Physics (2006).
  • D Armbruster, C de Beer, M Freitag, T Jagalski, Christian Ringhofer. Autonomous Control of Production Networks using a Pheromone Approach. PHYSICA (2006).
  • D Armbruster, P Degond, Christian Ringhofer. A Model for the Dynamics of large Queuing Networks and Supply Chains. SIAM J. Applied Mathematics (2006).
  • J Bourgade, P Degond, F Mehats, Christian Ringhofer. On quantum extensions to classical Spherical Harmonics Expansion Fokker-Planck models. Journal of Mathematical Physics (2006).
  • M Nedjalkov, D Vasileska, D Ferry, C Jacoboni, Christian Ringhofer. Wigner Transport models for electron phonon kinetics in quantum wires. Physical Review B (2006).
  • C Heitzinger, Christian Ringhofer. A Note on the Simplectic Integration of the Nonlinear Schroedinger Equation. Journal of Comp. Electronics (2005).
  • D Armbruster, Christian Ringhofer. Thermalized kinetic and fluid models for re-entrant supply chains. SIAM J. Multiscale Modeling and Simulation (2005).
  • D Vasileska, H Khan, S Ahmed, Christian Ringhofer, C Heitzinger. QUANTUM AND COULOMB EFFECTS IN NANODEVICES. International Journal of Nanoscience (2005).
  • M Nedjakov, H Kosina, S Selberherr, Christian Ringhofer, D Ferry. A unified particle approach to Wigner - Boltzmann transport in small semiconductor devices. Phys. Rev. B (2005).
  • P Degond, F Mehats, Christian Ringhofer. Quantum Energy-Transport and Drift-Diffusion models. Journal Stat. Phys (2005).
  • C Gardner, G Klimeck, Christian Ringhofer. Smooth Quantum Hydrodynamic Model vs. NEMO Simulation of Resonant Tunneling Diodes. Journal of Computational Electronics (2004).
  • D Armbruster, D Marthaler, Christian Ringhofer. Kinetic and Fluid Model Hierarchies for Supply Chains. SIAM J. Multiscale Modeling and Simulation (2004).
  • H Kosina, M Nedjalkov, Christian Ringhofer, S Selberherr. Semi-classical approximation of electron-phonon scattering beyond Fermi's Golden Rule. SIAM J. Appl. Math (2004).
  • Hasanur Khan, Dragica Vasileska, S Ahmed, Christian Ringhofer, Clemens Heitzinger. Modeling of FinFET: 3D MC Simulation Using FMM and Unintentional Doping Effects on Device Operation. Journal of Computational Electronics (2004).
  • S Ahmed, Christian Ringhofer, D Vasileska. An Effective Potential Approach to Modelling 25nm MOSFET Devices. Journal of Computational Electronics (2004).
  • S Ahmed, Christian Ringhofer, D Vasileska. Modeling Mosfets using effective potentials. Superlattices and Microstructures (2004).
  • C Gardner, Christian Ringhofer. Dispersive/Hyperbolic Hydrodynamic Models for Quantum Transport in Semiconductor Devices. IMA Volumes in Mathematics and its Applications (2003).
  • C Gardner, Christian Ringhofer. Dispersive/Hyperbolic Hydrodynamic Models for Quantum Transport in Semiconductor Devices in Dispersive Transport Equations and Multiscale Models. IMA Volumes in Mathematics and its Applications (2003).
  • Christian Ringhofer. A Mixed Spectral - Difference Method for the Steady State Boltzmann - Poisson System. SIAM J. Numerical Analysis (2003).
  • Christian Ringhofer. Numerical Methods for the Semiconductor Boltzmann Equation based on Spherical Harmonics Expansions and Entropy Discretizations. Transport Theory and Stat. Phys (2003).
  • Christian Ringhofer, C Gardner, D Vasileska. Effective Potentials and Quantum Fluid Models: A Thermodynamic Approach. Inter. J. on High Speed Electronics and Systems (2003).
  • L Shifren, Christian Ringhofer, D Ferry. A Wigner function based quantum ensemble Monte Carlo study of a resonant tunneling diode. IEEE Trans. Electron Devices (2003).
  • M Gobbert, Christian Ringhofer. A homogenization technique for the Boltzmann equation for low pressure chemical vapor deposition. SIAM J. Applied Mathematics (2003).
  • P Degond, Christian Ringhofer. A note on binary quantum collision operators conserving mass, momentum and energy. Compte Rendu Acad. Sci Paris (2003).
  • P Degond, Christian Ringhofer. A note on quantum moment hydrodynamics and the entropyprinciple. Compte Rendu Acad. Sci. Paris Ser (2003).
  • P Degond, Christian Ringhofer. Quantum moment hydrodynamics and the entropy principle. Journal Stat. Phys (2003).
  • Anile, A, Allegretto, W, Ringhofer, Christian. Mathematical Problems in Semiconductor Physics. (2003).
  • N BenAbdallah, C Gardner, O Pinaud, Christian Ringhofer. A Comparison of Resonant Tunneling Based on Schr¨o dinger's Equation and Quantum Hydrodynamics. VLSI Design (2002).
  • Armbruster, D, Marthaler, D, Ringhofer, Christian. Efficient simulations of supply chains. (2002).
  • Marthaler, D, Armbruster, Hans, Ringhofer, Christian. A mesoscopic approach to the simulation of semiconductor supply chains. Kluwer (2002).
  • Christian Ringhofer. An Entropy - Based Finite Difference Method for the Energy Transport System. Math. Mod. Meth. in Appl. Sci (2001).
  • Christian Ringhofer. Dissipative discretization methods for approximations to the Boltzmann equation. Math. Mod. Meth. in Appl. Sci (2001).
  • M Gobbert, Christian Ringhofer. Mesoscopic Scale Modeling for Chemical Vapor Deposition in Semiconductor Manufacturing. IMA Volumes in Mathematics and its Applications (2001).
  • J Soler, Christian Ringhofer. Discrete Schr¨odinger-Poisson systems preserving energy and mass. Applied Mathematics Letters (2000).
Research Activity: 
Teaching Website URL: 
https://math.la.asu.edu/~chris/
Spring 2022
Course NumberCourse Title
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Fall 2021
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 590Reading and Conference
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Spring 2021
Course NumberCourse Title
APM 526Adv Numerical Methds for PDEs
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Fall 2020
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 590Reading and Conference
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Spring 2020
Course NumberCourse Title
MAT 343Applied Linear Algebra
APM 526Adv Numerical Methds for PDEs
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Fall 2019
Course NumberCourse Title
MAT 590Reading and Conference
APM 792Research
APM 795Continuing Registration
APM 799Dissertation
Spring 2019
Course NumberCourse Title
MAT 343Applied Linear Algebra
APM 792Research
Fall 2018
Course NumberCourse Title
MAT 342Linear Algebra
MAT 343Applied Linear Algebra
MAT 590Reading and Conference
APM 792Research
Spring 2018
Course NumberCourse Title
APM 526Adv Numerical Methds for PDEs
APM 792Research
Fall 2017
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 590Reading and Conference
Presentations: 
  • C. Ringhofer. KINETICS DRIVEN BY LOCAL NASH EQUILIBRIA AND RISK AVERSE TRADING STRATEGIES. Modeling and Control in Social Dynamics, Rutgers U. New Jersey (Oct 2014).
  • christian ringhofer. AVERAGED KINETIC MODELS FOR PARTICLE FLOWS ON COMPLEX NETWORKS. Dynamical Systems Di?erential Equations and Applications, Madrid, Spain (Jul 2014).
  • C. Ringhofer. Wealth evolution in spatially structured economies driven by local Nash equilibria with risk averse trading strategies. Collective Behavior: Macroscopic versus Kinetic Descriptions, Imperial College, London (May 2014).
  • C. Ringhofer. METHODS FOR COMPUTATIONAL 2D PHOTOVOLTAICS. COLLOQUIUM, COLORADO STATE U (Apr 2014).
  • C. Ringhofer. KINETIC MODELS FOR CONFINED TRANSPORT. COLLOQUIUM, POLYTECHNICAL U. , AACHEN, FRG (Jan 2014).
  • C. Ringhofer. Optimizing geometries in complex networks. EURO-INFORMS 26th European Conference on Operational Research (Jul 2013).
  • C. Ringhofer. Averaged kinetic models for particle flows on complex networks. Theory and Numerics of Kinetic Equations, Saarbruecken, FRG (May 2013).
  • C. Ringhofer. HOMOGEMNIZATION OF COMPLEX FLOWS. Colloqium, University of Toulouse (May 2013).
  • C. Ringhofer. FROM MULTI AGENT MODELS TO CONTINUUM DESCRIPTIONS. Kinetic Description of Social Dynamics: From Consensus to Flocking, U. Maryland, Nov 5 - 9, 2012 (Nov 2012).
  • C.RINGHOFER. TRANSPORT IN NARROW GEOMETRIES UNDER STRONG CONFINEMENT. COLLOQUIUM, U. PAUL SABTIER, TOULOUSE, FRANCE (Nov 2012).
  • C. RINGHOFER. TRANSPORT IN NANOSCALE BIOLOGICAL DEVICES. OAK RIDGE NATL. LAB. COLLOQUIUM (Oct 2012).
  • C. RINGHOFER. KINETIC MODELS AND MULTI-SCALE CONTROL FOR AGENTS ON NETWORKS. KIT, U. TEXAS, AUSTIN (Apr 2012).
  • C. Ringhofer. AVERAGED KINETIC MODELS FOR PARTICLE FLOWS ON COMPLEX NETWORKS. Novel Applications of Kinetic Theory and Computations (October 17-21, 2011) ICERM Brown University (Oct 2011).
  • C. Ringhofer. CHARGED PARTICLE TRANSPORT IN NARROW GEOMETRIES UNDER STRONG CONFINEMENT WITH APPLICATIONS TO THE SIMULATION OF ION CHANNELS. Simulation of steady state transport in globally non-equilibrium systems, U. of Vienna (Jul 2011).
  • C. Ringhofer. Monte Carlo methods for flows on networks. Kinetic Description of Multiscale Phenomena, U. Wisconsin, Madison (May 2011).
  • C. Ringhofer. Continuum models for supply chain simulation. SOMMS Supply Chain Seminar (Mar 2011).
  • C. ringhofer. KINETIC THEORY FOR NETWORK FLOWS. Kinetic models of classical and quantum particle systems, Toulouse (Mar 2011).
  • C. Ringhofer. Multiphase methods, traffic rules and complex production systems. University of Vienna (Sep 2010).
  • C. Ringhofer. KINETIC THEORIES FOR CONFINED TRANSPORT. University Paul Sabatier / Toulouse, France (Jun 2010).
  • C. Ringhofer. SUB-BAND MODELING OF TRANSPORT IN NARROW GEOMETRIES. Kinetic Description of Multiscale Phenomena /Brown University (May 2010).
  • C. Ringhofer. KINETIC THEORIES FOR CONFINED TRANSPORT. SIAM Conference on Analysis of Partial Differential Equations, December 7-9, 2009 Miami, Florida Hil (Dec 2009).
  • C. RINGHOFER. CONFINED TRANSPORT IN BIOLOGICAL STRUCTURES. Summer School and Workshop on Kinetics and Statistical Methods for Complex Particle Systems, Lisbon, (Jul 2009).
  • christian ringhofer. KINETIC AND FLUID DYNAMIC MODELS FOR COMPLEX SUPPLY NETWORKS. C.I.M.E. Summer School on "Modelling and optimisation of flows on networks", (Jun 2009).
  • c. ringhofer. TRANSPORT IN NARROW GEOMETRIES UNDER STRONG CONFINEMENT. Conference On ‚Modern Topics in Nonlinear Kinetic Equations’,Cambridge, UK (Apr 2009).
  • c. ringhofer. Quantum and Kinetic Transport: Analysis Computations, and New Applications. IPAM Long Program: Quantum and Kinetic Transport: Analysis Computations, and New Applications (Feb 2009).
  • C. Ringhofer. COMPUTATIONAL ASPECTS OF SOLID STATE TRANSPORT. IMA -NSF workshop on Opportunities in solar ernergy research, UofM, Minneapolis (Nov 2008).
  • C. Ringhofer. Hyperbolic Models for Large Supply Chains. Applied and Comp. Math Seminar (Oct 2008).
  • C. Ringhofer. Open problems in kinetic and °uid models for multi - agent systems and con¯ned transport. Colloquium - FRG / U. of Maryland, College Park (Sep 2008).
  • C. Ringhofer and C. Heitzinger. Multi-scale Modeling and Simulation of Field-Effect Biosensors. SBMICRO2008, Porto Allegre, Brazil (Sep 2008).
  • C.Ringhofer. SERVICE RULES, FLUID MODELS AND TRAFFIC FLOW MODELS. ASU Supply chain seminar (Sep 2008).
  • C. Ringhofer. MAXIMUM ENTROPY CLOSURES FOR QUANTUM TRANSPORT IN CONFINED GEOMETRIES. IPAM Workshop: Entropies and Optimal Transport in Quantum Mechanics, UCLA (Jun 2008).
  • C. Ringhofer. Hyperbolic Models for Large Supply Chains. HYP2008, Uof Maryland, College Park (Jun 2008).
  • Ringhofer, Christian. Semi-classical Transport Models in Thin Slabs. SIAM Meeting on PDEs (Dec 2007).
  • Ringhofer, Christian. Modeling of Quantum Transport in Open Nanostructures. EQUADIFF (Aug 2007).
  • Ringhofer, Christian. Sub-Band Drift Diffusion Models for Quantum Transport in a Strong Force Regime. ICIAM 07 (Jul 2007).
  • Ringhofer, Christian. STOCHASTIC DYNAMICS OF LONG SUPPLY CHAINS WITH RANDOM BREAKDOWNS. ICIAM 07 (Jul 2007).
  • Ringhofer, Christian. AGGREGATE MODELS FOR THE SIMULATION OF PRODUCTION NETWORKS. Symposium Armbruster (Jun 2007).
  • Ringhofer, Christian, Heitzinger, C. Monte Carlo device simulation using effective quantum potemtials. International Workshop on Computational Electronics (Jun 2006).
  • Ringhofer, Christian. Quantum Monte Carlo methods based on a multi-scale approach. International Workshop on nonlinear PDE's (Jun 2006).
  • Ringhofer, Christian, Bourgade, P, Mauser, N. Quantum Corrections to Semiclassical Transport in Nanoscale Devices using Entropy Principles. International Workshop on Computational Electronics (Jun 2006).
  • Ringhofer, Christian, Gardner, C. Applications of Maximum Entropy Closures to Device Simulation. SEMIC 06 (Feb 2006).
  • Ringhofer, Christian. Charged particle models for the simulation of production networks. Nonlinear PDEs and Applications, Capital Normal University (Jul 2005).
  • Ringhofer, Christian. KINETIC AND FLUID MODELS FOR SUPPLY CHAIN SIMULATION. Thematic Institute on 'Complex Flows in Biological and Production Networks' (Jun 2005).
  • Ringhofer, Christian. ENTROPY BASED NUMERICAL KINETICS AND QUANTUM MECHANICAL CORRECTIONS. IPAM Workshop on Numerical Methods in Astrophysics (May 2005).
  • Ringhofer, Christian. CHARGED PARTICLE MODELS FOR THE SIMULATION OF PRODUCTION NETWORKS. HYKE meeting on 'Hyperbolic and Kinetic Equations' (May 2005).
  • Ringhofer, Christian. Kinetic equations in drift dominated regimes. Colloque au memoire de Frederic Poupaud (Mar 2005).
  • Ringhofer, Christian. FLUX LIMITED FLUID AND KINETIC MODELS FOR LARGE QUEUING NETWORKS. irst SIAM Conference on Partial Differential Equations (Dec 2004).
  • Ringhofer, Christian. KINETIC MODELS FOR RE-ENTRANT SUPPLY CHAINS. Mathematical Aspects of Fluid and Plasma Dynamics (MAFPD) (Oct 2004).
  • Ringhofer, Christian. DISSIPATIVE EFFECTS IN QUANTUM SYSTEMS AND THE ENTROPY PRINCIPLE. Technological Applications of PDE's (Feb 2004).
  • Ringhofer, Christian. Sub-Band Drift Diffusion Models for Quantum Transport in a Strong Force Regime. Colloquium
Expertise Areas: 
Applied Mathematics
Computational Mathematics