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computer science
systems analysis design
Questions and Answers of
Systems Analysis Design
Delineate the differences between components, entities, items, and CIs and their Entity Relationships (ERs)?
Who is responsible for identifying CIs?
What decision-making criteria are used to select CIs?
How do CIs relate to the specification tree?
What are COTS products and NDIs and how do they relate to items and CIs?
What is a configuration baseline?
What is the relationship between baselines and the Developmental Configuration?
What is meant by configuration effectivity?
Describe the evolution of the Developmental Configuration and its baseline.
What is the “As-Specified” Configuration, and when is it established?
What is the “As-Designed” Configuration, and when is it established?
What is the “As-Built” Configuration, and when is it established?
What is the “As-Verified” Configuration, and when is it established?
What is the “As-Validated” Configuration, and when is it established?
What is the “As-Maintained” Configuration, and when is it established?
What is the “As-Produced” Configuration, and when is it established?
What is the difference between Mission System versus Enabling System CIs? What are their relationships.Using an office building, automobile, and an aircraft, illustrate the relationships.
What is the difference between baseline management and CM?
What are the six primary approaches for developing components?
What is a COTS product?
What is a NDI?
What is AFP?
Who is the source of AFP?
How are COTS products procured?
How are NDIs procured?
What are the steps of the Component SelectionMethodology?
What questions should you ask vendors that may have products or services you are considering selecting?
What is a technical review?
Why should you conduct technical reviews?
Who is responsible for conducting technical reviews?
What types of technical reviews should be conducted?
How are technical reviews results documented?
What is the relationship between technical reviews and System Development Processes (Figure 12.2)? System System Definition Procurement Phase Phase System / Product Life Cycle System System
What is an IPR and what is it intended to accomplish?
What is a PMB?
What is an IBR and what is it intended to accomplish?
What is an SRR and what is it intended to accomplish?
What is an SDR and what is it intended to accomplish?
What is an HSR and SSR and what is it intended to accomplish?
What is an SSR and what is it intended to accomplish?
What is a PDR and what is it intended to accomplish?
What is a CDR and what is it intended to accomplish?
What is a TRR and what is it intended to accomplish?
What is a PRR and what is it intended to accomplish?
Figure P18-39 shows two similar unit pulse waveforms. The only difference is that the first pulse is positive from \(-T / 2\) to \(T / 2\), while the second pulse goes from \(+\mathrm{A}\) to
What is the most important criterion to use when selecting sensors for SIF applications?A. Ability to accurately measure the process variable B. IEC 61508 assessment C. Purchase cost D. Manufacturers
A single pressure transmitter (1oo1) is being used in a SIF to initiate a trip when the pressure output signal goes below 6 mA. This transmitter is connected to a safety PLC that is programmed to
A transmitter has failure rates as presented in Table 10-2. A proof test is performed every 5 years during a process shutdown. The proof test coverage is 92% and MTTRDD is 168 hours. After any
What type of flame detector would be selected for a burnermanagement system?
When would a fire and gas function be classified as a SIF?
When would a burner-management system function be classified as a SIF?
Can a relay logic system be used to satisfy the requirements for a SIL 3 SIF? What are some of the issues that must be addressed when using relays as a logic solver?
A safety-rated smart logic module might include what basic functionality?
If an IEC 61508 certified logic solver is selected, what prior use safety integrity justification is required?
A safety PLC has an Ethernet connection port used to send information to a data server in the system. Can this port be used without a cybersecurity risk?
A safety PLC has been certified to IEC 62443-4-1 and IEC 62443-4-2. Is this device guaranteed to be hacker proof?
List the advantages of using PLCs in safety applications, as compared to relays.
A SIF uses two discrete inputs and one discrete output. Based on the failure rates in Table 11-2, what is the total DU failure rate for the logic solver in this safety instrumented function?
What characteristics are required in a safety PLC?
A safety PLC manufacturer has stated that proof testing includes only physical inspection for deterioration and damage, and a check for unauthorized program changes Detailed test of the programmed
What CPT would be expected for a PVST with a timed pulse on a 3/2 pilot-operated spool solenoid valve?
A SIF uses a single, pneumatic, final element assembly consisting of a 3/2 pilot-operated poppet solenoid valve, a spring-return pneumatic piston actuator, and a floating ball valve. The application
A manufacturer has provided a self-certification for functional safety with a dangerous failure rate of 4 FITS for a 3/2 direct-acting poppet solenoid valve. Is this value realistic for the process
A SIF uses a single, pneumatic, final element assembly consisting of a 3/2 pilot-operated spool solenoid valve, a spring-return scotch yoke actuator, and a trunnion ball valve. The application is
A 3/2 solenoid valve is needed for a SIF final element. A CV rating of 0.1 is required. The lowest dangerous failure rate is desired. Which type of solenoid valve is the best choice?
The useful life of a device is often published in what document?
Why are proof test plans needed?
How can operations and maintenance capability be measured?
Proof test recommendations from a device manufacturer are often published in what document?
A set of nonredundant (1oo1) safety equipment is used to implement a SIF. Demands are expected every minute and DTI is 40 seconds. The following failure rate data are obtained by adding the failure
A set of nonredundant (1oo1) safety equipment, with all component devices certified as having systematic capability SC 3, is used in a low-demand application. The longest DTI of the equipment set is
A SIF description includes three valves. To protect against the hazard, valve one must be closed to cut off the fuel supply from natural gas. Valve two must be closed to preserve heat in a process
An overfill protection SIF has been designed with a level sensor, a safety PLC, and a final element assembly. The MT for the process unit is 15 years. The logic solver is programmed to shut down the
A software bug causes a logic solver to fail unpredictably and randomly. Will this failure be considered a random failure or a systematic failure? Why?
A manufacturer states that the failure rate for a pressure switch is constant and the MTBF is 2 years. What does this mean?A. The expected minimum life for the switch is 2 years B. The expected
Each of the 50 transmitters in identical service had a test time of 7,640 hours. During this period, three failures occurred. Calculate the failure rate.
Each of the 50 transmitters in identical service had a test time of 7,640 hours. During this period, no failures occurred. Describe the procedure for calculating the failure rate.
A failure rate report states that a level transmitter did not indicate high level in a storage tank. Proof testing performed each year did not detect the failure. The failure was traced to a failed
A failure report states that a safety transmitter signaled a high pressure in a vessel and initiated a trip. Other pressure measurements did not indicate any high pressure. A diagnostic in the safety
A device has a reliability of 0.95 for an interval of 1 year. What is the unreliability?
An instrument has a failure rate of 0.015 failures per year. What is the unreliability for a 5-year mission?
An instrument has a failure rate of 0.015 failures per year. All failures are immediately detectable. The MTTR is 24 hours. What is steady state unavailability?
An instrument has a failure rate of 0.015 failures per year. Failures are detected once per year when a periodic inspection is performed.Assuming perfect restoration, what is the PFavg?
A valve has a failure rate of 0.06 failures per year. A periodic inspection performed once a year can detect 60% of the failures. The valve is operated for 10 years before it is removed from service
During an annual inspection of an SIS, 5 of the 112 safety functions had a dangerous failure on the solenoid valve. What number should be assigned to the probability of dangerous failure for this
A system has a transmitter, a controller, and a valve. The probability of failure for the next 5 years equals 0.15 for the transmitter, 0.008 for the controller, and 0.19 for the valve. For the next
An instrument has an MTTF of 28,000 hours and an MTTR of 48 hours.What is the MTBF?
A device has a failure rate of 5 • 10-6 failures per hour. None of the failures are detected by any automatic diagnostics. The device is inspected every 2 years, and all failures are detected
A system is repairable. Since all failures are immediately recognizable, the restore time averages 48 hours. The percentage of downtime must be calculated for a 20-year expected system life. What is
For a gas burner to work without failure, one of two identical fans, the burner, and the controls must function without failure. The reliability of a fan is 0.9. The reliability of the burner is
A system has the following series-reliability block diagram:Failure rates are:λAC Power = 0.002 failures per year λDC Power Supply = 0.004 failures per year λLevel Switch = 0.02 failures per year
In Exercise 5.2, what is the reliability of the system for a 1-year time interval?A. 0.869 B. 0.131 C. 0.125 D. 0.9869 E. 0.877
A system has the following reliability block diagram: A B AC Power Motor
A system has four components with the RBD below. If the power supply has a 1-year reliability of 0.95 and the controller has a 1-year reliability of 0.99, what is the system reliability for 1 year?A.
Draw the Markov model for the system in Exercise 5.5.
Based on the system illustrated in the figure below, draw a fault tree to represent a safe failure (spurious trip) due to the failure of the TX1/2 subsystem; that is, the top event is “Nuisance
What is the P matrix for the Markov model in Figure 5-18? 5 Fail Energized 3 2. Degraded Detected 1 0 3 Comm. Loss 4 Degraded Undetected 2 Fail Safe 5 Figure 5-18. Example Markov model 24
Draw a Markov model for the system in Figure 5-6. Common Symbols Additional Symbols OR Gate AND Gate Event or Resulting Fault Basic Event Figure 5-6. Fault Tree Symbols Incomplete Event Inhibit Gate
A solenoid valve is energized in normal process operation. It is deenergized when a dangerous condition is detected and vents air from a pneumatic actuator. If the solenoid coil fails short circuit
A valve is designed to close on trip in a SIF. If this valve had a failure where internal seals were damaged and could not completely stop flow, how would this failure be classified?
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