Dr Jens-Dominik Mueller

Jens-Dominik Mueller

Reader
SEMS Academic Misconduct Officer, Head of Professional Bodies Liaison Group

School of Engineering and Materials Science
Queen Mary University of London
+44 (0)20 7882 5421
www.sems.qmul.ac.uk/staff/j.mueller/
Centre for Intelligent Transport
Centre for Sustainable Engineering
ORCID Google Scholar LinkedIn

Research

Computational Fluid Dynamics, Numerical Optimisation, Shape Optimisation, Adjoint and sensitivity methods, Data-driven modelling

Interests

Development of multi-disciplinary modelling chains that include sensitivity analysis.
Application of Automatic Differentiation tools to combine complete workflows from CAD to objective function.
Use of adjoint sensitivity methods in shape optimisation and data-driven modelling.

Publications

solid heart iconPublications of specific relevance to the Centre for Sustainable Engineering

2024

bullet iconHigh-Resolution CAD-Based Shape Parametrisation of a U-Bend Channel
Jesudasan R and Müeller J-D
Aerospace, Mdpi vol. 11 (8) 
13-08-2024

2023

bullet iconDiscrete adjoint for coupled conjugate heat transfer
Imam-Lawal O, Verstraete T and Müller JD
Structural and Multidisciplinary Optimization, Springer vol. 66 (5) 
17-04-2023
bullet iconA Review of Solution Stabilization Techniques for RANS CFD Solvers
Xu S, Zhao J, Wu H, Zhang S, Müller J-D, Huang H, Rahmati M and Wang D
Aerospace, Mdpi vol. 10 (3) 
26-02-2023

2022

bullet iconLES-aided shape optimization of U-Bend channel
Quadros R and Mueller J
8th European Congress on Computational Methods in Applied Sciences and Engineering. 
01-01-2022

2021

bullet iconFallow time determination in dentistry using aerosol measurement in mechanically and non-mechanically ventilated environments
Shahdad S, Hindocha A, Patel T, Cagney N, Mueller JD, Koched A, Seoudi N, Morgan C, Fleming PS and Din AR
British Dental Journal (Bdj), Springer Nature [Academic Journals On Nature.Com] 
24-08-2021
bullet iconA Unified Geometry Parametrization Method for Turbomachinery Blades
Agromayor R, Anand N, Müller JD, Pini M and Nord LO
Cad Computer Aided Design, Elsevier vol. 133 
02-01-2021
bullet iconCad-Based Adaptive Shape Parametrisation for Aerodynamic Shape Optimisation
Jesudasan R and Mueller J
14th WCCM-ECCOMAS Congress. 
01-01-2021

2020

bullet iconAn adjoint-assisted multilevel multifidelity method for uncertainty quantification and its application to turbomachinery manufacturing variability
Mohanamuraly P and Müller JD
International Journal For Numerical Methods in Engineering, Wiley 
30-12-2020
bullet iconQuantitative analysis of particulate matter release during orthodontic procedures: a pilot study
Din AR, Hindocha A, Patel T, Sudarshan S, Cagney N, Koched A, Mueller J-D, Seoudi N, Morgan C, Shahdad S and Fleming PS
British Dental Journal, Springer Nature, 1-7.  
12-11-2020
bullet iconA mesh adaptation strategy for complex wall-modeled turbomachinery LES
Odier N, Thacker A, Harnieh M, Staffelbach G, Gicquel L, Duchaine F, García Rosa N and Müller JD
Computers and Fluids, Elsevier vol. 214 
14-10-2020
bullet iconThe efficacy of an extraoral scavenging device on reduction of splatter contamination during dental aerosol generating procedures: an exploratory study
Shahdad S, Patel T, Hindocha A, Cagney N, Mueller JD, Seoudi N, Morgan C and Din A
British Dental Journal (Bdj), Springer Nature [Academic Journals On Nature.Com] 
11-09-2020
bullet iconConsistent treatment of incompletely converged iterative linear solvers in reverse-mode algorithmic differentiation
Akbarzadeh S, Hückelheim J and Müller JD
Computational Optimization and Applications, Springer (Part of Springer Nature) 
03-08-2020
bullet iconSeeding and adjoining zero-halo partitioned parallel scientific codes
Mohanamuraly P, Hascoët L and Müller JD
Optimization Methods and Software vol. 35 (3), 618-637.  
03-05-2020

2019

bullet iconA Newton–Krylov Solver for Robust Turbomachinery Aerodynamic Analysis
Xu S, Mueller J-D, Pavanakumar M and Wang D
Aiaa Journal: Devoted to Aerospace Research and Development, American Institute of Aeronautics and Astronautics 
24-12-2019
bullet iconGeometric continuity constraints of automatically derived parametrisations in CAD-based shape optimisation
Mueller J, ZHANG X, Akbarzadeh S and WANG Y
International Journal of Computational Fluid Dynamics, Taylor & Francis 
05-11-2019
bullet iconIntracranial aneurysms: looking beyond size in neuroimaging: the role of anatomical factors and haemodynamics
Roi DP, Mueller J-D, Lobotesis K, McCague C, Memarian S, Khan F and Mankad K
Quantitative Imaging in Medicine and Surgery vol. 9 (4), 537-545.  
01-04-2019

2018

bullet iconAlgorithmic differentiation of the Open CASCADE Technology CAD kernel and its coupling with an adjoint CFD solver
Banović M, Mykhaskiv O, Auriemma S, Walther A, Legrand H and Müller JD
Optimization Methods and Software vol. 33 (4-6), 813-828.  
02-11-2018
bullet iconParallelizable adjoint stencil computations using transposed forward-mode algorithmic differentiation
Hückelheim JC, Hovland PD, Strout MM and Müller JD
Optimization Methods and Software vol. 33 (4-6), 672-693.  
02-11-2018
bullet iconSensitivity Analysis and Gradient-based Optimisation of Feed Spacer Shape in Reverse Osmosis Membrane Processes Using Discrete Adjoint Approach
MUELLER J, Wang Y and HE W
Desalination, Elsevier 
17-10-2018
bullet iconAdjoint-Based Aerodynamic Optimisation of Wing Shape Using Non-uniform Rational B-Splines
Zhang X, Jesudasan R and Müller J-D
In Evolutionary and Deterministic Methods For Design Optimization and Control With Applications to Industrial and Societal Problems, Springer Nature 143-158.  
07-09-2018
bullet iconA Comparative Study of Two Different CAD-Based Mesh Deformation Methods for Structural Shape Optimization
Schwalbach M, Verstraete T, Müller J-D and Gauger N
In Evolutionary and Deterministic Methods For Design Optimization and Control With Applications to Industrial and Societal Problems, Springer Nature 47-60.  
07-09-2018
bullet iconApplications of differentiated CAD kernel in gradient-based aerodynamic shape optimisation
Auriemma S
2018 Joint Propulsion Conference. 
08-07-2018
bullet iconCheckpointing with Time Gaps for Unsteady Adjoint CFD
Hückelheim JC and Müller J-D
In Advances in Evolutionary and Deterministic Methods For Design, Optimization and Control in Engineering and Sciences, Springer Nature 117-130.  
03-07-2018
bullet iconSTAMPS: a Finite-Volume Solver Framework for Adjoint Codes Derived with Source-Transformation AD
Mueller J-D, Hueckelheim J and Mykhaskiv O
2018 Multidisciplinary Analysis and Optimization Conference. 
24-06-2018
bullet iconEvaluation of Integral Turbulence Scale Through the Fan Stage of a Turbofan Using Hot Wire Anemometry and Large Eddy Simulation
Odier N, Duchaine F, Gicquel L, Staffelbach G, Thacker A, Rosa NG, Dufour G and Muller J-D
Volume 2C: Turbomachinery., v02ct42a021-v02ct42a021.  
11-06-2018
bullet iconEvaluation of integral turbulence scale through the fan stage of a turbofan using hot wire anemometry and large eddy simulation
Odier N, Duchaine F, Gicquel L, Staffelbach G, Thacker A, García Rosa N, Dufour G and Muller JD
Proceedings of the ASME Turbo Expo. vol. 2C-2018 
01-01-2018

2017

bullet iconAdjoint Optimisation of Internal Turbine Cooling Channel Using NURBS-Based Automatic and Adaptive Parametrisation Method
Jesudasan R, Zhang X and Mueller J-D
Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions., v001t02a009-v001t02a009.  
07-12-2017
bullet iconNURBS-based and Parametric-based Shape Optimisation with differentiated CAD Kernel
mykhaskiv O, MUELLER J, Banovic M, Auriemma S, Mohanamuraly P, Walther A and Legrand H
Computer-Aided Design and Applications, Taylor & Francis 
02-11-2017
bullet iconWing-body junction optimisation with CAD-based parametrisation including a moving intersection
Xu S, Timme S, Mykhaskiv O and Müller JD
Aerospace Science and Technology vol. 68, 543-551.  
01-09-2017
bullet iconNURBS-based and Parametric-based Shape Optimisation with Differentiated CAD Kernel
Mykhaskiv O, Müller J-D, Mohanamuraly P, Banovic M, Walther A, Auriemma S and Legrand H
Proceedings of CAD'17., 415-419.  
10-08-2017
bullet iconA Mesh Adaptation Strategy to Predict Pressure Losses in LES of Swirled Flows
Daviller G, Brebion M, Xavier P, Staffelbach G, Müller JD and Poinsot T
Flow, Turbulence and Combustion vol. 99 (1), 93-118.  
01-07-2017
bullet iconReverse-mode algorithmic differentiation of an OpenMP-parallel compressible flow solver
MUELLER J, hueckelheim J, hovland P and Strout M
International Journal of High Performance Computing Applications, Sage Publications 
29-06-2017
bullet iconCAD-Based Adjoint Optimization of the Stresses in a Radial Turbine
Verstraete T, Müller L and Müller J-D
Volume 2C: Turbomachinery., v02ct47a025-v02ct47a025.  
26-06-2017
bullet iconADJOINT BASED DESIGN OPTIMISATION OF AN INTERNAL COOLING CHANNEL U-BEND FOR MINIMIZED PRESSURE LOSSES
MUELLER J, verstraete T and Mueller L
International Journal of Turbomachinery Propulsion and Power Editors: manna M. 
21-06-2017
bullet iconAdjoint-based design optimisation of an internal cooling channel u-bend for minimised pressure losses
Verstraete T, Müller L and Müller JD
International Journal of Turbomachinery, Propulsion and Power, Mdpi vol. 2 (2) 
21-06-2017
bullet iconCAD-based shape optimisation of the NASA CRM wing-body intersection using differentiated CAD-kernel
Mykhaskiv O, Mohanamuraly P, Mueller J-D, Xu S and Timme S
35th AIAA Applied Aerodynamics Conference. 
02-06-2017
bullet iconMultidisciplinary Adjoint Optimization of Trubomachinery Components Including Aerodynamic and Stress Performance
Verstraete T, Mueller L and Mueller J-D
35th AIAA Applied Aerodynamics Conference. 
02-06-2017
bullet iconAdjoint based design optimisation of an internal cooling channel u-bend for minimized pressure losses
Verstraete T, Müller L and Müller JD
EuroTurbo. 
01-04-2017
bullet iconSolving an inverse coupled conjugate heat transfer problem by an adjoint approach
Imam-Lawal OR, Verstraete T and Müller JD
Proceedings of the 7th International Conference on Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2017. vol. 2017-January, 788-799.  
01-01-2017
bullet iconCAD-based shape optimisation of the NASA CRM wing-body intersection using differentiated CAD-kernel
Mykhaskiv O, Mohanamuraly P, Müller JD, Xu S and Timme S
35th AIAA Applied Aerodynamics Conference, 2017. 
01-01-2017
bullet iconMultidisciplinary adjoint optimization of trubomachinery components including aerodynamic and stress performance
Verstraete T, Müller L and Müller JD
35th AIAA Applied Aerodynamics Conference, 2017. 
01-01-2017
bullet iconAdjoint based design optimisation of an internal cooling channel u-bend for minimized pressure losses
Verstraete T, Müller L and Müller JD
European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC. 
01-01-2017

2016

bullet iconAlgorithmic differentiation of code with multiple context-specific activities
Hückelheim JC, Hascoët L and Müller JD
Acm Transactions On Intelligent Systems and Technology vol. 43 (4) 
01-12-2016
bullet iconA comparison of node-based and CAD-based automatic parametrisations in shape optimisation
JESUDASAN R, Gugala M, Mykhaskiv O and Mueller J
11th ASMO UK/ISSMO/NOED2016: International Conference on Numerical Optimisation Methods for Engineering Design Technische Universität München - Germany (TUM/Garching) 18 Jul 2016 - 20 Jul 2016. 
18-07-2016
bullet iconCAD-free vs CAD-based parametrisation method in adjoint-based​ aerodynamic shape optimization
JESUDASAN R, Zhang X, Gugala M and Mueller J
European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS-2016) Crete, Greece 5 Jun 2016 - 10 Jun 2016. 
05-06-2016
bullet iconHYBRID PARALLELISATION OF AN ALGORITHMICALLY DIFFERENTIATED ADJOINT SOLVER
Mohanamuraly P, Huckelheim JC and Mueller J-D
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)., 1268-1276.  
01-01-2016
bullet iconGEOMETRIC CONTINUITY CONSTRAINTS FOR ADJACENT NURBS PATCHES IN SHAPE OPTIMISATION
Zhang X, Wang Y, Gugala M and Mueller J-D
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)., 3985-3998.  
01-01-2016
bullet iconTOWARDS AN OUTPUT-BASED RE-MESHING FOR TURBOMACHINERY APPLICATIONS
Gugala M, Meyer M and Mueller J-D
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)., 4011-4022.  
01-01-2016
bullet iconOPTIMISATION OF A U-BEND USING A CAD-BASED ADJOINT METHOD WITH DIFFERENTIATED CAD KERNEL
Auriemma S, Banovic M, Mykhaskiv O, Legrand H, Mueller J-D, Verstraete T and Walther A
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)., 4023-4034.  
01-01-2016

2015

bullet iconLES Study of Transverse Acoustic Instabilities in a Swirled Kerosene/Air Combustion Chamber
Ghani A, Poinsot T, Gicquel L and Müller JD
Flow, Turbulence and Combustion vol. 96 (1), 207-226.  
06-10-2015
bullet iconStabilisation of discrete steady adjoint solvers
Xu S, Radford D, Meyer M and Müller JD
Journal of Computational Physics vol. 299, 175-195.  
07-07-2015
bullet iconStabilisation of Discrete Adjoint Solvers for Incompressible Flow
Wang Y, Akbarzadeh S and Mueller JD
22nd AIAA Computational Fluid Dynamics Conference. 
18-06-2015
bullet iconFixed point discrete adjoint of SIMPLE-like solvers
Akbarzadeh S, Wang Y and Mueller JD
22nd AIAA Computational Fluid Dynamics Conference. 
18-06-2015
bullet iconCAD-Based Adjoint Shape Optimisation of a One-Stage Turbine With Geometric Constraints
Xu S, Radford D, Meyer M and Müller J-D
Volume 2C: Turbomachinery., v02ct45a006-v02ct45a006.  
15-06-2015
bullet iconComputation of the Tangent-Linear Solution for LCO-Converged Nonlinear Flows
Xu S, Hückelheim J, Gugala M and Müller J-D
53rd AIAA Aerospace Sciences Meeting. 
03-01-2015
bullet iconTime-averaged steady vs. unsteady adjoint: a comparison for cases with mild unsteadiness
Hueckelheim J, Xu S, Gugala M and Müller J-D
53rd AIAA Aerospace Sciences Meeting. 
02-01-2015
bullet iconStabilisation of discrete adjoint solvers for incompressible flow
Wang Y, Akbarzadeh S and Müller JD
22nd AIAA Computational Fluid Dynamics Conference. 
01-01-2015
bullet iconEssentials of computational fluid dynamics
Müller JD
 
01-01-2015

2013

bullet iconCAD-based shape optimisation with CFD using a discrete adjoint
Xu S, Jahn W and Müller J-D
International Journal For Numerical Methods in Fluids 
01-01-2013

2012

bullet iconOne-shot optimisation with grid adaptation using adjoint sensitivities (ECCOMAS 2012)
Jaworski AB, Müller JD and Rokicki J
Eccomas 2012 - European Congress On Computational Methods in Applied Sciences and Engineering, E-Book Full Papers, 3685-3693.  
01-12-2012
bullet iconCFD development with automatic differentiation
Jones D, Müller JD and Bayyuk S
50th Aiaa Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition 
01-12-2012
bullet iconAcoustic and Large Eddy Simulation studies of azimuthal modes in annular combustion chambers
Wolf P, Staffelbach G, Gicquel LYM, Müller JD and Poinsot T
Combustion and Flame vol. 159 (11), 3398-3413.  
01-11-2012
bullet iconSensitivity of flow simulations in a cerebral aneurysm
Müller JD, Jitsumura M and Müller-Kronast NHF
Journal of Biomechanics vol. 45 (15), 2539-2548.  
11-10-2012
bullet iconSensitivity of flow simulations in a cerebral aneurysm
Muller J-D, Jitsumura M and Mueller-Kronast NHF
Journal of Biomechanics vol. 45 (15), 2539-2548.  
01-01-2012
bullet iconAcoustic and Large Eddy Simulation studies of azimuthal modes in annular combustion chambers
Wolf P, Staffelbach G, Gicquel LYM, Müller J-D and Poinsot T
Combustion and Flame 
01-01-2012
bullet iconGoal-based flow optimisation for automotive design
Mueller J-D, Jones D, Jahn W, Othmer C, Megahed M, Hollette N, Pierrot G, Bletzinger K-U and Stavropolou E
Transport Research Arena 2012 vol. 48, 3599-3612.  
01-01-2012

2011

bullet iconPreparation and assembly of discrete adjoint CFD codes
Jones D, Müller JD and Christakopoulos F
Computers and Fluids vol. 46 (1), 282-286.  
01-07-2011
bullet iconCAD-based shape optimisation using adjoint sensitivities
Yu G, Müller JD, Jones D and Christakopoulos F
Computers and Fluids vol. 46 (1), 512-516.  
01-07-2011
bullet iconA modelling approach to aid the understanding of high volume image guided injection in recalcitrant achilles tendinopathy
Twycross-Lewis R, Lu Y, Malliaras P, Mueller J-D and Maffulli N
British Journal of Sports Medicine, Bmj vol. 45 (2) 
20-01-2011
bullet iconPseudo-timestepping and verification for automatic differentiation derived CFD codes
Christakopoulos F, Jones D and Mueller J-D
Computers & Fluids vol. 46 (1), 174-179.  
01-01-2011

2010

bullet iconChallenges of developing engineering students' writing through peer assessment
McConlogue T, Mueller J and Shelton J
Engineering Education 2010: Inspiring The Next Generation of Engineers, Ee 2010 
01-12-2010
bullet iconDiscretisation of diffusive fluxes on hybrid grids
Puigt G, Auffray V and Müller JD
Journal of Computational Physics vol. 229 (5), 1425-1447.  
01-03-2010

2008

bullet iconToward modular multigrid design optimisation
Jaworski A and Müller JD
Lecture Notes in Computational Science and Engineering vol. 64 LNCSE, 281-291.  
20-10-2008
bullet iconValidation of a fluid-structure interaction model for a bileaflet mechanical heart valve
Forsythe N and Mueller JD
Int J Comput Fluid D vol. 22 (8), 541-553.  
01-01-2008

2005

bullet iconOn the performance of discrete adjoint CFD codes using automatic differentiation
Muller JD and Cusdin P
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS. vol. 47 (8-9), 939-945.  
20-03-2005

2004

bullet iconGenerating efficient code with automatic differentiation
Cusdin P and Müller JD
ECCOMAS 2004 - European Congress on Computational Methods in Applied Sciences and Engineering. 
01-12-2004

2003

bullet iconAlgorithm developments for discrete adjoint methods
Giles MB, Duta MC, Müller JD and Pierce NA
Aiaa Journal vol. 41 (2), 198-205.  
01-01-2003

2002

bullet iconAnisotropic adaptation and multigrid for hybrid grids
Müller JD
International Journal for Numerical Methods in Fluids. vol. 40 (3-4), 445-455.  
30-09-2002
bullet iconEdge-based multigrid and preconditioning for hybrid grids
Moinier P, Müller JD and Giles MB
Aiaa Journal vol. 40 (10), 1954-1960.  
01-01-2002

2001

bullet iconAdaptive local grid refinement for unsteady reacting flows
Müller JD, Schönfeld ET and Légier JP
15th Aiaa Computational Fluid Dynamics Conference 
01-12-2001
bullet iconSolution adaptive mesh refinement using adjoint error analysis
Müller JD and Giles MB
15th Aiaa Computational Fluid Dynamics Conference 
01-12-2001
bullet iconAdjoint code developments using the exact discrete approach
Giles M, Duta M and Mueller J-D
15th AIAA Computational Fluid Dynamics Conference. 
11-06-2001

1999

bullet iconEdge-based multigrid and preconditioning for hybrid grids
Moinier P and Mueller J-D
14th Computational Fluid Dynamics Conference. 
22-08-1999
bullet iconEdge-based multigrid and preconditioning for hybrid grids
Moinier P, Müller JD and Giles MB
14th Computational Fluid Dynamics Conference. 
01-01-1999

1997

bullet iconA comparison of the treatment of hanging nodes for hybrid grid refinement
Mueller J-D, Schoenfeld T, Rudgyard M and Mueller J-D
13th Computational Fluid Dynamics Conference. 
29-06-1997
bullet iconA comparison of the treatment of hanging nodes for hybrid grid refinement
Müller JD, Schönfeld T and Rudgyard M
13th Computational Fluid Dynamics Conference. 
01-01-1997

1996

bullet iconAn object-oriented approach to hybrid structured/unstructured grid generation
Banks D, Mueller J-D and Vankeirsbilck P
34th Aerospace Sciences Meeting and Exhibit. 
15-01-1996

1994

bullet iconQuality estimates and stretched meshes based on Delaunay triangulations
Muller J-D
Aiaa Journal, American Institute of Aeronautics and Astronautics (Aiaa) vol. 32 (12), 2372-2379.  
01-12-1994

1993

bullet iconA frontal approach for internal node generation in Delaunay triangulations
Müller J, Roe PL and Deconinck H
International Journal For Numerical Methods in Fluids, Wiley vol. 17 (3), 241-255.  
15-08-1993
bullet iconProven angular bounds and stretched triangulations with the frontal delaunay method
Müller JD
11th Computational Fluid Dynamics Conference, 1993., 546-554.  
01-01-1993
bullet iconComputations of inviscid compressible flows using fluctuation-splitting on triangular meshes
Paillère H, Deconinck H, Struijs R, Roe PL, Mesaros LM and Müller JD
11th Computational Fluid Dynamics Conference, 1993., 36-50.  
01-01-1993

Grants

solid heart iconGrants of specific relevance to the Centre for Sustainable Engineering
bullet iconComputational methods for active flow control using adoint sensitivities
Jens-Dominik Mueller
£179,947 EU Commission - Horizon 2020
01-09-2020 - 31-08-2022
bullet iconMHI2: mixing plane, nozzle vane
Jens-Dominik Mueller
£186,258 Mitsubishi Heavy Industries
01-01-2019 - 30-06-2023
bullet iconCAD-based wing optimisation for the XRF1 - CASE studentship Airbus
Jens-Dominik Mueller
£27,000 Airbus Defence & Space Ltd
01-09-2018 - 31-08-2022
bullet iconParallel Multigrid and Mesh Refinement
Jens-Dominik Mueller
£58,294 Rolls-Royce Deutschland Ltd & Co KG
01-10-2016 - 31-08-2020
bullet iconMADDOG - Multidisciplinary Adjoint Design Optimisation of Gasturbines
Jens-Dominik Mueller
£127,046 EU Commission - Horizon 2020
01-09-2015 - 31-08-2017
bullet iconIODA
Jens-Dominik Mueller
£734,361 EU Commission - Horizon 2020
01-01-2015 - 31-12-2018