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Lectured topics within these three subject areas are indicated in the lecture plan below. Textbook for subject area 1 is Reliability of Safety-Critical Systems: Theory and Applications, while the compendium, Maintenance optimization lecture notes,
is available for subject area 2.
A collection of formulas is updated after each lecture. This collection may be brought to the exam.
Week | Date
| Subject | Lectured topics | Motivation | Lecturer | Tutorials | |||||||||
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3534 | 25. 19 & 2620.8 | All | 1st hour:
2nd-3rd hours
| Inform the students about the course objectives, intended learning outcomes, and practicalities.
| Mary Ann |
| and Jørn |
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35 | 26.-27.8 | 1 | Safety | 36 | 2.-3.9 | 1 | Safety-critical systems: | IEC 61508 is a key standard on design of safety-critical systems, when the technology used include electrical, | Mary Ann |
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36 | 2.-3.9 | 1 | Safety-critical systems: | 37 | 9.-10.9 | 1 | Safety-critical systems: (chapter 2, plus supplemented material: | The mentioned IEC standard(s) require a structured process for defining SIL requirements. Methods like layers of protection analysis (LOPA) and risk graph are often used for this purpose. Risk graph is used with many applications, such as for machinery and process industry, whereas LOPA is mainly used in the process industry. In the oil and gas industry, for example, it is common to have LOPA-sessions/workshops in an early planning of new systems. A special case of defining SIL requirements is the minimum SIL, advocated in a Norwegian guideline for offshore oil and gas facility, Norsk Olje og Gass guideline 070. This approach builds on principles called GALE or GAMAB. | Mary Ann |
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37 | 9.-10 | 38 | 16.-17.9 | 1 | Safety-critical systems: (Textbook chapter 5 and 8) | PetriNets is an alternative approach for calculating the the the average probability of failure on demand (PFD). | Yiliu (Mary Ann |
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3938 | 2316.-2417.9 | 1 | Safety-critical systems: Quantification of reliability for systems operating on demand - Extending the simplified formulas (Textbook chapter 8) | Students that take this course are familiar with simplified formulas for calculating the average probability of failure on demand (PFD).
| Mary Ann |
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4039 | 3023.9-124.109 | 1 | Safety-critical systems: Modeling of CCFs and determining of the value of the beta factor. (Textbook chapter 10) | Common cause failures (CCFs) are often the main contributor to the probability of failure for redundant systems. The students
| Mary Ann |
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4140 | 730.9-81.10 | 1 | Safety-critical systems: Quantification of reliability for systems operating on demand with focus on partial and imperfect testing (Textbook chapter 11) | It is not always realistic that the proof tests and the associated repair actions are "perfect", meaning that the system is restored to an as good as new state after each test. One reason may be that it is not safe to simulate a real "demand" (would you test fire detectors by putting fire to a room?). The simulated test (pressing a test-button) may not be so extensive, and some failures may be left undiscovered also after the test. Another reason may be that it is not desired to carry out a perfect test. Testing of valves, for example, require that the valve is operated from opened to closed position (or visa versa), but this may require a full stop of the plant. Instead, it may be suggested to replace some perfect tests with partial tests, so that the valve is just operated some %, and then returned to its initial position. This lecture focus on how to account for such factors in the quantification of PFD. | Mary Ann |
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4241 | 147.-158.10 | 1 | Safety-critical systems: Quantification of reliability for systems operating in the high demand mode (Textbook chapter 9) | Not all safety-critical systems operate on demand. For example, many machinery safety functions are always or so often demanded that the PFD is no longer a useful reliability measure. Another example is railway signaling systems controlling the setting of light signals and position of rails switches. In this case, another reliability measure is suggested in standards like IEC 61508, called failure frequency (PFH). This lecture explains how the PFH is calculated for typical system architectures. | Mary Ann |
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4342 | 2114.-2215.10 | 1 | Safety-critical systems: Quantification of spurious trips (Textbook chapter 10) | A fail-safe design of a safety-critical system favors a transition to the safe state, which in most | Mary Ann |
| 44 | ||||||||
43 | 21-2227&28.10 | 2 | Spare-part optimization | Spare parts may be costly to have on the stock, but at the same time it is costly not to have a spare part available when it is needed. This topic concern how to calculate the probability of running out of spares, using simple formulas and Markov analyses. The use of PetriNets for this purpose is also shown. This topic may not be some relevant for very specialized systems, where it is not possible to acquire a spare within short time. For a manufacturer that develops products, such as sensors, in a large scale to e.g. the oil and gas industry, it may be relevant to find the optimal number of spare parts for warranty and repair services. | Yiliu | ||||||||||
44 | 27&28.10 | 2 | Age, block, and minimal repair strategies | Maintenance optimization:
| Age, block, and minimal repair strategies | Maintenance optimization:
| Jørn | 45 | 4&5.11 | 2 | Age, block, and minimal repair strategies (continued) |
| Jørn | ||
4645 | 114&12.115.11 | 2 | Age, block, and minimal repair strategies (continued) | See above. | Jørn | ||||||||||
46 | 11&12.11 | 2 | Topic to be scheduled (Anne Barros) | Anne | 2 | Spare-part optimization | Spare parts may be costly to have on the stock, but at the same time it is costly not to have a spare part available when it is needed. This topic concern how to calculate the probability of running out of spares, using simple formulas and Markov analyses. The use of PetriNets for this purpose is also shown. This topic may not be some relevant for very specialized systems, where it is not possible to acquire a spare within short time. For a manufacturer that develops products, such as sensors, in a large scale to e.g. the oil and gas industry, it may be relevant to find the optimal number of spare parts for warranty and repair services. | Yiliu | |||||||
47 | 18.&19.11 | N/A | Student presentations (also using tutorial hours) | Students get the possibility to reflect on the lectured topics and in particular to see how these are related to their specialization project, and how they may be applicable for their master project. | |||||||||||
48 | 26.11 | Summary (in tutorial hours, due to IPK traveling on 24-25.11) | Mary Ann | ||||||||||||
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