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9thand 10thedition answers from chegg.com (where applicable to 10thedition)Chapter 121.1.Identify six consumer products that are likely to be controlled by safety-critical software systems.Hazard:A condition with the potential for causing or contributing to an accident. A failure of the sensor that measures blood glucose is an example of hazard.Hazard probability:The probability of the events occurring which create a hazard. Probability values tend to be arbitrary but range from “probable” to “implausible”Accident:An unplanned event or sequence of events which results in human death or injury, damage to property, or to the environmentHazard severity:An assessment of the worst possible damage that could result from a particular hazard. Hazard severity can range from catastrophic, where many people are killed, to minor, where only minor damage results.Risk:This is a measure of the probability that the system will cause an accident. The risk is assessed by considering the hazard probability, the hazard severity, and the probability that the hazard will lead to an accident. The risk of an insulin overdose is probably medium to low.Damage:A measure of the loss resulting from a mishap. Damage can range from many people being killed as a result of an accident to minor injury or property damage.1.2.A software system is to be deployed for a company that has extremely high safety standards and allows for almost no risks, not even minor injuries. How will this affect the look of the risktriangle in Figure 12.3?
In the risk triangle the boundary between the regions is not technical but rather depends on social and political factors. The boundaries in the risk triangle are liable to change with time and changing social attitudes. It is so because, the acceptance or negligence of a risk sometimes depend on the time and the risk that occurred. At some point of the time the risk may appear as tolerable but sometimes the severity may be high. The acceptance and assessment depends on the changing minds of the people.For example, risks that were thought to be improbable may be reclassified as intolerable because of events, such as terrorist attacks, or accidents that have occurred.Over time, society has become more risk averse so the boundaries have moved downward. Although the financial costs of accepting risks and paying for any resulting accidents may be less than the costs of accident prevention, public opinion may demand that money be spent to reduce the likelihood of a system accident, thus incurring additional costs. For example, it may be cheaper for a company to clean up pollution on the rare occasion it occurs, rather than to install systems for pollution prevention.