v0.6.0: Common Cause Failure Models

Release Notes

Incorporation of Common Cause Failure.

Major Changes

• Common Cause Failure models:
  • Beta Factor
  • Multiple Greek Letters
  • Alpha Factor
  • Phi Factor

Since v0.5.0

• 42 commits resulted in 50 files changed, 2740 insertions(+), 304 deletions(-)

v0.5.0: New algorithms, Importance Analysis, and Fault Tree Preprocessing

Release Notes

This release introduces a new cut set generation algorithm that is faster than the previous algorithm. In addition, the release adds importance analysis and initial attempts to preprocess and simplify fault trees. A new analysis engine is introduced for easier preprocessing.

Major Changes

• New algorithms to efficiently generate cut sets (at least 10x improvement):
  • Early set uniqueness detection
  • Local minimality detection upon cut set expansions
• Fault tree preproccessing:
  • Constant propagation
  • Application of Boolean algebra basics for fault tree simplifications
  • Complex gate expansions for XOR and ATLEAST
  • Original module (independent sub-tree) detection
  • Simple new module creation
• Importance analysis:
  • Fussel-Vesely
  • Birnbaum
  • Critical Importance Factor
  • Risk Reduction Worth
  • Risk Achievement Worth
• Importance factors only for basic events in minimal cut sets. The other basic events are 0 importance.
• Calculations without probability information assume House event state as false.
• Separate consideration for certain basic events for uncertainty analysis:
  • Only basic events with distributions are left in probability equation.
• Multiple input files with fault trees and model data are accepted for analysis.
• Simple logging system for debugging or warning.

Fixed Bugs

• House events are treated as constant in the fault tree not as regular basic events.
• House events are not included in minimal cut sets or reported with probability information anymore.
• Unity is treated in Boolean algebra for minimal cut sets. The special case of Unity top gate is handled.
• Repeated children are detected in input files. One gate cannot have the same two children in input.

Since v0.4.0

• 116 commits resulted in 226 files changed, 5342 insertions(+), 37071 deletions(-)

v0.4.0: Uncertainty Analysis

Release Notes

This release introduces uncertainty analysis and more support for OpenPSA expressions.

Major Changes

• Uncertainty analysis with Monte Carlo method
• Automated performance testing
• Probability calculation performance optimization (up to 10x faster)
• The default number of series in probability calculations is set to 7 (conservative result with acceptable performance).
• cppclean code problem check
• Lowered cyclomatic complexity of the core code (CCN < 15)
• Bug fixes of wrong output into a file
• Bug fix in log-normal distribution
• OpenPSA MEF support additions:
  • Expressions:
    • Constant expressions
    • System mission time
    • Parameter
    • Random deviate (normal, log-normal, histogram, uniform, gamma, beta)
    • Built-in expressions (exponential with two parameters, exponential with four parameters, Weibull)
• More theory information in documentations.
• Re-introduction of deprecated Inhibit gate, Conditional and Undeveloped events.

Deprecated Features

• Vote gate is renamed to "atleast".

Since v0.3.1

• 124 commits resulted in 120 files changed, 10455 insertions(+), 3244 deletions(-)

v0.3.1: More platforms and XML support

Release Notes

Major Changes

• Pre-expansion of gates (around 4x faster tree expansion).
• Verified building for Mac OS X with macports.
• Verified building for Windows with Cygwin.
• Various statistical distributions for Monte Carlo Method and random number generator.
• OpenPSA MEF support additions:
  • Several fault trees in one input file.
  • Attributes
  • Label
• Warnings for unused primary events.
• More example fault tree inputs.
• KDE CMake coding style and corrected function declarations according to Google Style.
• Start of GUI development with Qt
• CDash reporting.

Since v0.3.0

• 93 commits resulted in 265 files changed, 79505 insertions(+), 31439 deletions(-)

v0.3.0: OpenPSA Model Exchange Format Support

Release Notes

This release introduces a refactored structure of the core code and support for XML input files.

Major Changes

• XML input files formatted according to OpenPSA Model Exchange Format
  • RelaxNG validation of input files.
• Refactored code structure conceptually similar to the structure of the XML tree from the input file.
• Three entities: Gates, Basic events, House events.
• Performance optimization of the tree expansion (around 1.5x faster) and MCS generation (around 3x faster)
• Cut-off probability for cut sets is introduced for faster probability calculations (around 40-50x faster)
• Gates can be easily re-used without creating TransferIn/Out input files
• The fault tree generator script outputs XML input file

Deprecated Features

• The previous custom input formats for a fault tree and event probabilities
• L-model probability description with failure rates (This will be implemented by more broad expressions in future)
• TransferIn and TransferOut are not gate-like types but symbols to represent the re-use of gates.
• Undeveloped/Conditional event will be treated just like a basic event with an additional description.

Since v0.2.0

• 131 commits resulted in 305 files changed 15863 insertions and 22968 deletions.

v0.2.0: Static Fault Tree Analysis

Release Notes

• New Gates and Event types:
  • NULL
  • NOT
  • NOR
  • NAND
  • XOR
  • VOTE
  • Inhibit
  • Conditional Event
• Performance improvements for minimal cut set generation.
• Initial Complexity analysis for main functions.
• Probability calculation from failure rates.
• MCUB Approximation for probability calculations.
• Better output formatting.
• Better graphing with colors.
• Time reporting.
• Bug fixes related to name clashes.
• Documentation of API and publishing by Doxygen.
• Better documentation website.
• References and information about most used MCS algorithms: MOCUS and BDD.

Since v0.1.2

• SCRAM: 97 commits resulted in 89 files changed with 3782 insertions and 953 deletions.

v0.2.0-rc2:Needs better installation instructions.

Complexity analysis for probability calculation functions.

Closes #7.

v0.2.0-rc1: Needs Tests, Refactoring, Documentation

Colors are added for graphing fault trees.

v0.1.2: Transfer Trees and Documentation

Release Notes

• Analysis and graphing of a sub-tree without a main tree input file.
• Bug fixes related to analysis of a sub-tree and its graphing.
• Documentation is published on gh-pages.

Since v0.1.1

• SCRAM: 21 commits resulted in 50 changed files encompassing a net 4137
  line insertions(+) and 665 deletions(-).

v0.1.1: Testing, Bug Fixes, Benchmarking

Release Notes

This release introduces unit, integration, and benchmarking tests, as well as several bug fixes.

Major changes

• Testing suite
  • unit tests
  • integration tests
  • benchmarking tests
• Continuous Integration by Travis-CI.
• Automated Coverity scan for code quality and resource leak analysis.
• Test coverage check by Coveralls.
• Several bug fixes for input file parsing and fault tree instantiation.
• Better memory management with boost smart pointers.

Since v0.1

• SCRAM: 116 commits resulted in 107 changed files encompassing a net 4799
  line insertions(+) and 923 deletions(-).