Ecolego
Encyclopedia
Ecolego is a simulation software
tool that is used for creating dynamic models and performing deterministic and probabilistic simulations. It is also used for conducting risk assessments
of complex dynamic systems evolving over time.
Ecolego can be applied in a variety of areas, but is mainly used for risk assessment
in radioecology
, environmental physics
and PBPK modeling
. To facilitate the use of Ecolego in the field of radiology
, specialized databases and other add-ons have been developed. For example, all radionuclides and their decay products have been integrated in the software.
(SSM)
, the authority in Sweden responsible for the regulation of radioactive waste management and disposal, and NRPA
, the Norwegian Radiation Protection Authority.
The software was initially developed as a complimentary user interface to create compartmental models
in Simulink
. Simulink had very powerful and fast solvers for ordinary differential equations, but lacked support for running probabilistic simulations and handling of parameter values. Also, Simulink is very detailed – every equation is modeled by graphically operator blocks– making modeling time consuming and prone to mistakes.
By relying on Simulink for simulations, full attention could be given to the development of an advanced user interface.
As more and more features where added to Ecolego, the need for an integrated simulation engine grew. With the release of Ecolego 4 in 2008, a set of state-of-the-art solvers was incorporated and thus removed the dependence of Simulink.
Today, SSM uses Ecolego for the review of SKB's (the Swedish Nuclear Waste Management Company) license application for the siting and construction of a repository for the final disposal of spent nuclear fuel in Sweden.
/Simulink
to perform simulations.
February 2006: Ecolego 2.1 was released. The user interface of Ecolego was completely remade, and now used a tiling window manager
to improve model transparency.
2007: Ecolego 3 was released. Ecolego now featured a crude integrated calculation engine, reducing the dependence on Matlab/Simulink. The support for probabilistic analysis was greatly improved. A built-in database for parameter values and radionuclide properties was added. Support for hierarchical containers.
2008: Ecolego 4 was released. Ecolego 4 now incorporated state-of-the-art solvers for ordinary differential equations, making Matlab/Simulink redundant. The user interface was improved with many new windows for navigation, report generation and presentation of simulation results. Copy/paste functionality was added.
Fall of 2009: the current version of Ecolego, Ecolego 5, was released. Ecolego 5 added many features, such as unit checking, sub-version support and a model component library. The sensitivity analysis where extended, and a toolbox for advanced sensitivity analysis was created (see EIKOS).
With the purpose to make complicated models with many interconnections easier to overview, the models in Ecolego are represented with the help of interaction matrices instead of the traditional flow diagrams. Combined with hierarchical containers (sub-systems), the interaction matrix greatly facilitates construction and documentation of large and complex models.
Objects can be assigned comments, images, units, and hyper links to other documents or Ecolego objects. Ecolego can also create reports that contain everything from interaction matrices, to parameter values, equations, decay chains, plots and tables. The report can be saved in many different formats, including PDF and HTML.
In order to increase the flexibility for the user, Ecolego has no restrictions on the order of creation – for instance, a parameter can be used in equations before it is defined. A real-time validation engine reports problems to the user, such as not-yet-defined objects, objects lacking values or having invalid equations.
Several other features in Ecolego promote quality assurance:
which requires a solver of differential equations. There is a wide array of numerical solvers to choose from. Some are optimized for stiff and numerically difficult models, others for trivial models.
With an extensive list of probability density functions
, together with Monte Carlo
and Latin hypercube sampling
and parameter correlation settings, Ecolego holds all the required tools to perform advanced probabilistic analysis.
The software features the same functionality as Ecolego, with the exception that the integral structure of the model cannot be changed. However, with a module library created in Ecolego, the user can assemble models by combining components from the library.
in Ecolego, the Sensitivity Analysis Toolbox is an optional module which gives a larger set of tools for this approach.
The Eikos Sensitivity Analysis toolbox supports state of the art sensitivity analysis methods (local as well as global). Sensitivity analysis (SA) is used to assess the influence of model parameters on model predictions.
Correlations between parameters may be induced by rank order correlation (method of Iman and Conover). The supported sampling techniques are: Monte carlo, Latin Hypercube and Quasi-random LPt.
The SA methods included are:
Eikos provides a Graphical User Interface (GUI) which lets you:
Facilia AB homepage: http://www.facilia.se
Simulation software
Simulation software is based on the process of modeling a real phenomenon with a set of mathematical formulas. It is, essentially, a program that allows the user to observe an operation through simulation without actually performing that operation...
tool that is used for creating dynamic models and performing deterministic and probabilistic simulations. It is also used for conducting risk assessments
Risk assessment
Risk assessment is a step in a risk management procedure. Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat...
of complex dynamic systems evolving over time.
Ecolego can be applied in a variety of areas, but is mainly used for risk assessment
Risk assessment
Risk assessment is a step in a risk management procedure. Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat...
in radioecology
Radioecology
Radioecology is a branch of ecology, which studies how radioactive substances interact with nature; how different mechanisms affect the substances’ migration and uptake in food chain and ecosystems...
, environmental physics
Environmental science
Environmental science is an interdisciplinary academic field that integrates physical and biological sciences, to the study of the environment, and the solution of environmental problems...
and PBPK modeling
Physiologically-based pharmacokinetic modelling
-What is a PBPK model?:Physiologically based pharmacokinetic modeling is a mathematical modeling technique for predicting the absorption, distribution, metabolism and excretion of synthetic or natural chemical substances in humans and other animal species...
. To facilitate the use of Ecolego in the field of radiology
Radiology
Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. Radiologists use an array of imaging technologies to diagnose or treat diseases...
, specialized databases and other add-ons have been developed. For example, all radionuclides and their decay products have been integrated in the software.
History
Ecolego was co-founded by Swedish Radiation Safety AuthoritySwedish Radiation Safety Authority
The Swedish Radiation Safety Authority is the Swedish government authority responsible for radiation protection. It sorts under the Ministry of the Environment....
(SSM)
, the authority in Sweden responsible for the regulation of radioactive waste management and disposal, and NRPA
, the Norwegian Radiation Protection Authority.
The software was initially developed as a complimentary user interface to create compartmental models
Multi-compartment model
A multi-compartment model is a type of mathematical model used for describing the way materials or energies are transmitted among the compartments of a system. Each compartment is assumed to be a homogenous entity within which the entities being modelled are equivalent...
in Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
. Simulink had very powerful and fast solvers for ordinary differential equations, but lacked support for running probabilistic simulations and handling of parameter values. Also, Simulink is very detailed – every equation is modeled by graphically operator blocks– making modeling time consuming and prone to mistakes.
By relying on Simulink for simulations, full attention could be given to the development of an advanced user interface.
As more and more features where added to Ecolego, the need for an integrated simulation engine grew. With the release of Ecolego 4 in 2008, a set of state-of-the-art solvers was incorporated and thus removed the dependence of Simulink.
Today, SSM uses Ecolego for the review of SKB's (the Swedish Nuclear Waste Management Company) license application for the siting and construction of a repository for the final disposal of spent nuclear fuel in Sweden.
Releases
December 2003: the first version, Ecolego 1.0, was released. In this early version, the software was dependent on MatlabMATLAB
MATLAB is a numerical computing environment and fourth-generation programming language. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages,...
/Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
to perform simulations.
February 2006: Ecolego 2.1 was released. The user interface of Ecolego was completely remade, and now used a tiling window manager
Tiling window manager
In computing, a tiling window manager is a window manager with an organization of the screen into mutually non-overlapping frames, as opposed to the more popular approach of coordinate-based stacking of overlapping objects that tries to fully emulate the desktop metaphor.-Xerox PARC:Although the...
to improve model transparency.
2007: Ecolego 3 was released. Ecolego now featured a crude integrated calculation engine, reducing the dependence on Matlab/Simulink. The support for probabilistic analysis was greatly improved. A built-in database for parameter values and radionuclide properties was added. Support for hierarchical containers.
2008: Ecolego 4 was released. Ecolego 4 now incorporated state-of-the-art solvers for ordinary differential equations, making Matlab/Simulink redundant. The user interface was improved with many new windows for navigation, report generation and presentation of simulation results. Copy/paste functionality was added.
Fall of 2009: the current version of Ecolego, Ecolego 5, was released. Ecolego 5 added many features, such as unit checking, sub-version support and a model component library. The sensitivity analysis where extended, and a toolbox for advanced sensitivity analysis was created (see EIKOS).
Modeling environment
The initial idea of Ecolego was to facilitate creation of large and complex models and to be able to solve difficult numerical problems.With the purpose to make complicated models with many interconnections easier to overview, the models in Ecolego are represented with the help of interaction matrices instead of the traditional flow diagrams. Combined with hierarchical containers (sub-systems), the interaction matrix greatly facilitates construction and documentation of large and complex models.
Objects can be assigned comments, images, units, and hyper links to other documents or Ecolego objects. Ecolego can also create reports that contain everything from interaction matrices, to parameter values, equations, decay chains, plots and tables. The report can be saved in many different formats, including PDF and HTML.
In order to increase the flexibility for the user, Ecolego has no restrictions on the order of creation – for instance, a parameter can be used in equations before it is defined. A real-time validation engine reports problems to the user, such as not-yet-defined objects, objects lacking values or having invalid equations.
Quality assurance
Modules can be created by defining inputs and outputs for sub-systems. By adding modules to the integrated library, a user can create a palette of validated building blocks that can be combined to form new models. The library can be exported, so that users with Ecolego Player can use it to create models without the need of an Ecolego license.Several other features in Ecolego promote quality assurance:
- Unit checking
- Version handling of models through subversion
- Parameter databases (internal or external)
- Integrated database for radionuclide properties
Simulations
The typical Ecolego model is a compartmental modelMulti-compartment model
A multi-compartment model is a type of mathematical model used for describing the way materials or energies are transmitted among the compartments of a system. Each compartment is assumed to be a homogenous entity within which the entities being modelled are equivalent...
which requires a solver of differential equations. There is a wide array of numerical solvers to choose from. Some are optimized for stiff and numerically difficult models, others for trivial models.
With an extensive list of probability density functions
Probability density function
In probability theory, a probability density function , or density of a continuous random variable is a function that describes the relative likelihood for this random variable to occur at a given point. The probability for the random variable to fall within a particular region is given by the...
, together with Monte Carlo
Monte Carlo
Monte Carlo is an administrative area of the Principality of Monaco....
and Latin hypercube sampling
Latin hypercube sampling
Latin hypercube sampling is a statistical method for generating a distribution of plausible collections of parameter values from a multidimensional distribution. The sampling method is often applied in uncertainty analysis....
and parameter correlation settings, Ecolego holds all the required tools to perform advanced probabilistic analysis.
Ecolego Player
Ecolego Player is a free software that makes it possible to perform calculations with Ecolego models without having access to Ecolego.The software features the same functionality as Ecolego, with the exception that the integral structure of the model cannot be changed. However, with a module library created in Ecolego, the user can assemble models by combining components from the library.
Ecolego Sensitivity Analysis Toolbox (Eikos)
Although it is possible to perform sensitivity analysisSensitivity analysis
Sensitivity analysis is the study of how the variation in the output of a statistical model can be attributed to different variations in the inputs of the model. Put another way, it is a technique for systematically changing variables in a model to determine the effects of such changes.In any...
in Ecolego, the Sensitivity Analysis Toolbox is an optional module which gives a larger set of tools for this approach.
The Eikos Sensitivity Analysis toolbox supports state of the art sensitivity analysis methods (local as well as global). Sensitivity analysis (SA) is used to assess the influence of model parameters on model predictions.
Correlations between parameters may be induced by rank order correlation (method of Iman and Conover). The supported sampling techniques are: Monte carlo, Latin Hypercube and Quasi-random LPt.
The SA methods included are:
- Morris screening method
- Extended Fourier Amplitude Sensitivity Test (EFAST)
- Sobol (first, custom and total order)
- Random balance design
- Local sensitivity
- Garten’s method
Eikos provides a Graphical User Interface (GUI) which lets you:
- Specify uncertain model parameters and model outputs of interest
- Generate and inspect input samples
- Export input and output samples generated in Eikos
- Import input and outputs samples generated externally into Eikos
- Simulate and inspect the model output samples
- Perform Sensitivity Analysis of model predictions
- Graphically review the results using pie charts, scatter plots, tornado graphs, etc.
External links
Ecolego official homepage: http://www.ecolego.facilia.seFacilia AB homepage: http://www.facilia.se