Verification & Validation
Safety-Critical Systems

INTECS is especially active in the field of V&V (Verification & Validation) of complex systems within different areas and markets such as the “Railway Signalling Systems” and “Avionic Systems” markets described in the following.



Certification of operational safety-critical systems
Execution of the activities involved in the certification of already operational safety-critical systems (“legacy”) for which evidence of the Integrity level reached by the system has to be produced, according to the CENELEC certification recommendations (EN 50128). Such activities foresee the definition of a specific life-cycle including different phases such as the followings:

- Safety Analysis / Hazard Analysis
- Definition of a certification process according  to the assigned System Integrity Level (“SIL”)
- Re-engineering of the requirements (Formalisation, Verification, etc.)
- Requirements Traceability management top-down and bottom-up including the use of Requirements Management tools ensuring proper coverage
Software Reverse Engineering
Documentation set production according to CENELEC recommendations

Software Testing
Design and implementation of tests foreseen by the CENELEC standards (EN 50126, EN 50128) related to the applicable “SIL” with the objective of verifying the complete requirements coverage level identified for the various development life-cycles: (i) module tests (ii) software integration tests, (iii) hardware/software integration tests and (iv) system-level tests using simulators.

Safety Assessment
INTECS provides Italian and European Notified Bodies with consultancy services for the assessment, at software and system level, of safety-critical systems, for  railway signalling systems according to the CENELEC EN 50128, EN 50126, and EN 50129 standards and according to the applicable “SIL”. These activities include involvement in laboratory and /or field tests. 

Functional assessment for Railway systems
The activity, carried out for railway agencies, consists of the functional assessment of signalling plants (SCMT, ERTMS, SSC) through the use of check-lists and data-bases for requirements traceability, defined according to railway agency regulations and based on the project documentation provided by the manufacturer.

Design Verification for SCMT applications 
INTECS performs Verification & Validation of SCMT signalling plants constructed by suppliers for railway agencies. The activity consists of the verification of the project characteristics reported by the documentation and also in the verification, by means of an independent parallel design process, of the RFI's (Rete Ferroviaria Italiana) reference specifications. 


INTECS, participates to design, development, testing and IV&V, of Avionic Systems (e.g.: EFA, TORNADO, M346) developed according to international avionic standards for safety-critical systems: DOD-STD-2167 and RTCA/DO-178A.

Such systems are designed according to a life-cycle that, in addition to the normal development phases and to the IV&V phases, includes advanced verification techniques such as the followings:


- Hazard Analysis
- High Integrity Ada Sublanguage,
- Process Schedulability Analysis,
- Code Complexity Analysis,
- Structural Coverage (white box testing),
- Modified Condition Decision Coverage (MCDC),
- Dynamic Analysis,
- Object Code Verification (source to binary correlation).

Furthermore, the design and the implementation of such systems includes the adoption of specific risk mitigation techniques typical of Safety-Critical systems such as: partitioning, hard-Real Time, cyclic process scheduling and deadlines, defensive programming, BIT and health monitoring, and adoption of bus-architectures for safety-critical systems.

The main technologies and  tools involved in the V&V activities related to the Safety-Critical systems are the followings:  

· Cantata™
· Vector CAST™
· Telelogic DOORS™, Sinergy™, DOORS NET™
· Logiscope™
· Suite Rational®
· Purify®, ProLint®, SP Lint
· UML, UML Nice
· Item tool kit
· Relex
· Autocad®
· Motorola 68xx
· Power PC
· MIL-HDBK-217F, RDF 2000
· MIL-STD-1553 Bus Family
· Ada language
· Assembly language
· ANSI C, C++
· High Integrity Ada Sublanguage (Praxis SPARK tool)
· IEC 61508 Electronic System Functional Safety
· IEC 61511 Process & Industry Functional Safety