Categories - Energy Systems - Energy System Modeling Frameworks

Topics

loadflow, power-system-analysis, adequacy, sequential-decision-making-problems, gymnasium, load-flow, optimisation-model, mathematical-modelling, short-circuit, modelling-framework, power-system-dynamics, bilan, powsybl, previsionnel, tyndp, rte, system, reopt-api, mixed-integer-linear-programming, energy-planners, investment, distribution-shift, power-system-stabilizer, power-system-stability, students, power-system-dynamic-modeling, power-grid, gridcal, klu, linopy, esdl, energy-transition-calculation, energy-information, description-language, datamodel, stochastic-simulation-algorithm, manipulatewidge, electric, dygraphs, rhdf5, spine-toolbox, miniconda, anaconda, very-large-scale-systems, tight-and-compact-formulation, power-to-hydrogen, network-constrained-unit-commitment, integrated-resource-planning, hydro-cascade-basins, hourly-resolution, generation-storage-networks-investments, energy-storage-systems, dynamic-investment-decisions, dc-power-flow, dispatch, decarbonisation, reoptjl, reopt-lite-api, state-estimation, synchronous-machine, stability, psp-ufu, industry-aplication, harmonics, graphical-user-interface, free-libre-open-source-software, free-and-open-source-software, computer-aided-design, times, optimization-model, integrated-markal-efom, bottom-up-model, water-energy-nexus, unit-commitment, substations, renewable-resources, n-1-criterion, electricity-supply, economic-dispatch, dispatchable-units, dc-flow, FAME, modular, groovy, extensible, energy-optimization-model, timedomain, small-signal, modeling-dae, eigenvalue-analysis, andes, matpower-github, energy-systems-modelling, quasi-stationary, emt, electromagnetic-transient, dynamic-phasors, process-systems-engineering, modelling-tool, cgmes, typical-periods, aggregation, glpk, energy-models, user-defined-control,

Projects

Contributors

jinningwang [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: curent, large-scale, messaging, power-grids, power-system, power-system-analysis, simulation-framework, best-of, best-of-list, co-simulation and 19 more

c.syranidou [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Olexandr Balyk [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: bottom-up-model, energy-system-model, gams, integrated-markal-efom, optimization-model, times, times-ireland-model, denmark, scenario-analysis, times-model and 3 more

Lara Welder [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Robin Beer [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Sebastian Galarza [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

oliver.or.rehberg [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Felix Kullmann [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Dennis Labordus [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: 61850scl, der, iec61850, pacs, scl, substation, iec, cim, iec-cim, docker-compose and 1 more

Nolting [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Theresa Groß [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Michael Zier [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Priesmann [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Stefan Kraus [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Thorsten Burandt [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-model, energy-planners, investment, osemosys, students, energy-system, gams

Nis Martensen [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: capacity-expansion-planning, clean-energy, climate-change, electrical-engineering, energy-system, energy-systems, loadflow, optimal-power-flow, optimisation, power-flow and 14 more

Stefan Pfenninger [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, optimisation, pyomo

Bettina Schäfer [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dynamic-phasors, electromagnetic-transient, emt, power-systems, powerflow, quasi-stationary

Brian.Cultice [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics:

graeme [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, optimisation, pyomo

Matthias Zech [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

jboukas [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

eva38032 [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: energy-system, modelling-framework

Damien [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

navia [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

Beneharo [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

ChiaraMagni21 [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

mpavicevic [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

RasmusBramstoft [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

fraukewiese [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

evajoskin [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

Juan Gea Bermudez [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

Martijn Backer [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

Petra Raussi [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dynamic-phasors, electromagnetic-transient, emt, power-systems, powerflow, quasi-stationary

Leon [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Sylvain [email protected]

OST Projects: 1
Categories: Consumption, Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks, Mobility and Transportation
Topics: dispatch, power, declination, geo, geophysics, igrf, igrf13, magnetic, magnetism, journey-planner and 32 more

Arun Subramanian [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: description-language, dsl, energy-information, energy-transition, energy-transition-calculation, esdl, interoperability

Balz [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Tom Franssens [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dispatch, power

Mathias157 [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

TheisUM [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model

Leonhard-B [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

WYAUDI [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Sam West [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: data-processing, energy-systems-modelling, open-science, times-model

Olexandr Balyk [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: energy-system-model, gams, integrated-markal-efom, optimisation-model, data-processing, energy-systems-modelling, open-science, times-model

Jan Pieter Wijbenga [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: description-language, dsl, energy-information, energy-transition, energy-transition-calculation, esdl, interoperability, domain-specific-language, transition

FLabG [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: dc-power-flow, dynamic-investment-decisions, energy-storage-systems, generation-storage-networks-investments, hourly-resolution, hydro-cascade-basins, network-constrained-unit-commitment, power-to-hydrogen, tight-and-compact-formulation, very-large-scale-systems and 1 more

Theo Weiss [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics:

Michiaki Tatsubori [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

dogauzrek [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

AFM Kamal Chowdhury [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dc-flow, dispatchable-units, economic-dispatch, electricity-supply, n-1-criterion, power-system-analysis, renewable-resources, substations, unit-commitment, water-energy-nexus and 7 more

smuellr [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

lodersky [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

baumbude [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: climate-change, energy-system, energy-system-modeling, energy-systems, mathematical-modelling, milp, mixed-integer-linear-programming, optimisation, renewables

Peter Stange [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: climate-change, energy-system, energy-system-modeling, energy-systems, mathematical-modelling, milp, mixed-integer-linear-programming, optimisation, renewables

fel15133 [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: climate-change, energy-system, energy-system-modeling, energy-systems, mathematical-modelling, milp, mixed-integer-linear-programming, optimisation, renewables

Felix Panitz [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: climate-change, energy-system, energy-system-modeling, energy-systems, mathematical-modelling, milp, mixed-integer-linear-programming, optimisation, renewables

fpanitz [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: climate-change, energy-system, energy-system-modeling, energy-systems, mathematical-modelling, milp, mixed-integer-linear-programming, optimisation, renewables

yunusozsahin [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Mert Alpaslan [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Andres Ramos [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dc-power-flow, dynamic-investment-decisions, energy-storage-systems, generation-storage-networks-investments, hourly-resolution, hydro-cascade-basins, network-constrained-unit-commitment, power-to-hydrogen, tight-and-compact-formulation, very-large-scale-systems and 1 more

Roderick Go [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: mathematical-programming, modeling-language, nonlinear-programming

Magdalena Dorfner [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Konrad Schönleber [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Panos Xenos [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: loadflow, power, powerflow, short-circuit, state-estimation, system

Jakob Kirschner [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: loadflow, power, powerflow, short-circuit, state-estimation, system

tfabian [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: loadflow, power, powerflow, short-circuit, state-estimation, system

Ghanshyam Malaviya [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: loadflow, power, powerflow, short-circuit, state-estimation, system

lodersky [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

adeeljsid [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, mathematical-modelling, optimisation-model, pyomo

Matthew Prilliman [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Youssef Boulkaid [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-model, energy-planners, investment, osemosys, students, activejob, activerecord, mvc

Sam Kramer [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics:

Cord Kaldemeyer [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: energy-system, modelling-framework

cphili [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: cim, energy-system, extensible, groovy, modular, power-system-simulation, power-systems, powsybl

Markus Mirz [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: dynamic-phasors, electromagnetic-transient, emt, power-systems, powerflow, quasi-stationary

Thom [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

mcllerena [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: electrical, energy-system, nrel, powersystems

Ethan Wilk [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: distribution-shift, energy-system, reinforcement-learning

NathanDissoubray [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: cim, energy-system, extensible, groovy, modular, power-system-simulation, power-systems, powsybl

Xinhe Chen [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

Kyle Skolfield [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

Andrew Lee [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

Jordan Jalving [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, gradient-boosted-trees, keras-neural-networks, mathematical-modelling, mathematical-programming, mixed-integer-optimization, mixed-integer-programming, modeling-language and 6 more

Chrispine Tinega [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: capacity-expansion-planning, clean-energy, climate-change, electrical-engineering, energy-system, energy-systems, linopy, loadflow, optimal-power-flow, optimisation and 7 more

ARH [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics:

Chinedu Okoli [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

chineduokoli [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

Hamdy Elgammal [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

lezneew [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: loadflow, power, powerflow, short-circuit, state-estimation, system

Christopher Hanselman [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering, idaesplus

pjle014 [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics:

Quang Minh Le [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: chemical-engineering, process-modeling, process-systems-engineering

Philibert Parquier [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, power-system-simulation, power-systems, power-systems-analysis

Thibaut VERMEULEN [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, power-system-simulation, power-systems, power-systems-analysis

Hantao Cui [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: andes, eigenvalue-analysis, modeling-dae, power-system, power-system-analysis, power-system-dynamics, power-system-simulation, powerflow, small-signal, timedomain and 19 more

THEVENON Gerard Ext [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system, power-system-simulation, power-systems, power-systems-analysis

Xiaogang He [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: hydropower, renewable-energy, reservoir-modeling, climate-change, droughts, floods, hydrology

JN-TBW-EX [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy System Modeling Frameworks
Topics: capacity-expansion-planning, clean-energy, climate-change, electrical-engineering, energy-system, energy-systems, linopy, loadflow, optimal-power-flow, optimisation and 7 more

tilseb [email protected]

OST Projects: 1
Categories: Energy Systems
Sub Categories: Energy Modeling and Optimization, Energy System Modeling Frameworks
Topics: energy-system-model, gams, optimisation-model