Software Engineering 8th Edition Ian Sommerville - Solutions

Discover comprehensive support for "Software Engineering 8th Edition by Ian Sommerville" with our extensive range of resources. Access the online answers key and solutions manual to tackle challenging questions and enhance your understanding of the textbook. Our solutions PDF offers clear, step-by-step answers, ensuring you grasp complex concepts with ease. Delve into solved problems and chapter solutions to reinforce learning. Benefit from our instructor manual and test bank to prepare thoroughly. Enjoy the convenience of a free download, providing you with all the questions and answers needed for success in your studies.

=+ She proposes that it should be put into use as a production system, with new features added as required. This avoids the expense of system development and makes the system immediately useful. Write a short report for your manager explaining why prototype systems should not normally be used as
=+2.8. You have developed a prototype of a software system and your manager is very impressed by it.
=+government were not very clear, a software company was tasked with the development of a prototype. The government found the prototype impressive, and asked it be extended to be the actual system that would be used. Discuss the pros and cons of taking this approach.
=+2.7. Imagine that a government wants a software program that helps to keep track of the utilization of the country’s vast mineral resources. Although the requirements put forward by the
=+2.6. Explain why software testing should always be an incremental, staged activity. Are programmers the best people to test the programs that they have developed?
=+interface design, and component design are interdependent.
=+2.5. Using an example, explain why the design activities of architectural design, database design,
=+2.4. Suggest why it is important to make a distinction between developing the user requirements and developing system requirements in the requirements engineering process.
=+2.3. Consider the integration and configuration process model shown in Figure 2.3. Explain why it is essential to repeat the requirements engineering activity in the process.
=+2.2. Incremental software development could be very effectively used for customers who do not have a clear idea about the systems needed for their operations. Discuss.
=+An interactive travel planning system that helps users plan journeys with the lowest environmental impact
=+A university accounting system that replaces an existing system
=+A virtual reality system to support software maintenance
=+A system to control antilock braking in a car
=+2.1. Suggest the most appropriate generic software process model that might be used as a basis for managing the development of the following systems. Explain your answer according to the type of system being developed:
You are a systems engineer and are asked to suggest the best way to develop the safetycritical software for a heart pacemaker. You suggest formally specifying the system, but your manager rejects your suggestion. You think his reasons are weak and based on prejudice. Is it ethical to develop the
Z supports the notion of sequences where a sequence is like an array. For example, for a sequence S, you can refer to its elements as S[1], S[2], and so on. It also allows you to determine the number of elements in a sequence using the # operator. That is, if a sequence S is [a,b, c, d] then #S is
Write a Z schema called SELF_TEST that tests the hardware components of the insulin pump and sets the value of the state variable HardwareTest?. Then modify the RUN schema to check that the hardware is operating successfully before any insulin is delivered. If not, the dose delivered should be zero
Modify the insulin pump schema, shown in Figure 10.10, to add a further safety condition that the ManualDeliveryButton? can only have a non-zero value if the pump switch is in the manual position.
Bank teller machines rely on using information on the user’s card giving the bank identifier, the account number and the user’s personal identifier. They also derive account information from a central database and update that database on completion of a transaction. Using your knowledge of ATM
to allow aircraft to occupy the same height in the sector so long as they are separated by at least 8 km of horizontal difference. You may ignore aircraft in adjacent sectors. Hint: You have to modify the constructor operations so that they include the aircraft position as well as its height. You
In the example of a controlled airspace sector, the safety condition is that aircraft may not be within 300 m of height in the same sector. Modify the specification shown in Figure
An abstract data type representing a stack has the following operations associated with it:New: Bring a stack into existence.Push: Add an element to the top of the stack.Top: Evaluate the element on top of the stack.Retract: Remove the top element from the stack and return the modified stack.Empty:
Explain why it is particularly important to define sub-system interfaces in a precise way and why algebraic specification is particularly appropriate for sub-system interface specification.
You have been given the task of ‘selling’ formal specification techniques to a software development organisation. Outline how you would go about explaining the advantages of formal specifications to sceptical, practising software engineers.
Suggest why the architectural design of a system should precede the development of a formal specification.
As an expert in computer security, you have been approached by an organisation that campaigns for the rights of torture victims and have been asked to help them gain unauthorised access to the computer systems of a British company. This will help them confirm or deny that this company is selling
Should software engineers working on the specification and development of safety-related systems be professionally certified in some way? Explain your reasoning.
A train protection system automatically applies the brakes of a train if the speed limit for a segment of track is exceeded or if the train enters a track segment that is currently signalled with a red light (i.e., the segment should not be entered). Giving reasons for your answer, chose a
You are responsible for writing the specification for a software system that controls a network of EPOS (electronic point of sale) terminals in a store. The system accepts bar code information from a terminal, queries a product database and returns the item name and its price to the terminal for
Suggest appropriate reliability metrics for the following classes of software system. Give reasons for your choice of metric. Predict the usage of these systems and suggest appropriate values for the reliability metrics:■ A system that monitors patients in a hospital intensive care unit■ A word
Explain why it is practically impossible to validate reliability specifications when these are expressed in terms of a very small number of failures over the total lifetime of a system.
What is the fundamental difference between hardware and software failures? Given this difference, explain why hardware reliability metrics are often inappropriate for measuring software reliability.
Suggest how fault-tree analysis could be modified for use in security specification. Threats in a security-critical system are analogous to hazards in a safety-critical system.
Describe three important differences between the processes of safety specification and security specification.
A safety-critical software system for treating cancer patients has two principal components:■ A radiation therapy machine that delivers controlled doses of radiation to tumour sites.This machine is controlled by an embedded software system.■ A treatment database that includes details of the
In the insulin pump system, the user has to change the needle and insulin supply at regular intervals and may also change the maximum single dose and the maximum daily dose that may be administered. Suggest three user errors that might occur and propose safety requirements that would avoid these
Explain why the boundaries in the risk triangle shown in Figure 9.2 are liable to change with time and with changing social attitudes.
Under what circumstances would you recommend against using structured methods for system development?
Develop a sequence diagram showing the interactions involved when a student registers for a course in a university. Courses may have limited enrolment, so the registration process must include checks that places are available. Assume that the student accesses an electronic course catalogue to find
Develop an object model, including a class hierarchy diagram and an aggregation diagram showing the principal components of a personal computer system and its system software.
Using the information about the system data shown in Figure 8.8, draw a sequence diagram that shows a possible sequence of actions that occur when a new article is catalogued by the LIBSYS system.
Model the object classes that might be used in an e-mail system. If you have tried Exercise 8.3, describe the similarities and differences between the data processing model and the object model.
A software system model may be represented as a directed graph where nodes are the entities in the model and arcs are the relationships between these entities. Entities and relationships in the model may be labelled with a name and other information. Each entity in the model is typed and may be
Draw state machine models of the control software for:■ An automatic washing machine that has different programs for different types of clothes■ The software for a DVD player■ A telephone answering system that records incoming messages and displays the number of accepted messages on an LED.
Model the data processing that might take place in an e-mail system. You should model the mail-sending and mail-receiving processing separately.
Based on your experience with a bank ATM, draw a data-flow diagram modelling the data processing involved when a customer withdraws cash from the machine.
Draw a context model for a patient information system in a hospital. You may make any reasonable assumptions about the other hospital systems that are available, but your model must include a patient admissions system and an image storage system for X-rays, as well as other diagnostic records.
Your company uses a standard analysis method that is normally applied in all requirements analyses. In your work, you find that this method cannot represent social factors that are significant in the system you are analysing. You point this out to your manager, who makes it clear that the standard
When emergency changes have to be made to systems, the system software may have to be modified before changes to the requirements have been approved. Suggest a process model for making these modifications that ensures that the requirements document and the system implementation do not become
Why do traceability matrices become difficult to manage when there are many system requirements? Design a requirements structuring mechanism, based on viewpoints, which might help reduce the scale of this problem.
Who should be involved in a requirements review? Draw a process model showing how a requirements review might be organised.
Discuss an example of a type of system where social and political factors might strongly influence the system requirements. Explain why these factors are important in your example.
Using your knowledge of how an ATM is used, develop a set of use-cases that could serve as a basis for understanding the requirements for an ATM system.
The LIBSYS system has to include support for cataloguing new documents where the system catalog may be distributed across several machines. What are likely to be the most important types of non-functional requirements associated with the cataloguing facilities?
For three of the viewpoints identified in the library system, LIBSYS (Figure 7.4), suggest three requirements that could be suggested by stakeholders associated with that viewpoint.
A software system is to be developed to manage the records of patients who enter a clinic for treatment. The records include records of all regular patient monitoring (temperature, blood pressure, etc.), treatments given, patient reactions and so on. After treatment, the records of their stay are
Suggest who might be stakeholders in a university student records system. Explain why it is almost inevitable that the requirements of different stakeholders will conflict in some way.
You have taken a job with a software user who has contracted your previous employer to develop a system for them. You discover that your company’s interpretation of the requirements is different from the interpretation taken by your previous employer. Discuss what you should do in such a
Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements.
Write a set of non-functional requirements for the ticket-issuing system, setting out its expected reliability and its response time.
Describe four types of non-functional requirements that may be placed on a system. Give examples of each of these types of requirement.
Using the technique suggested here, where natural language is presented in a standard way, write plausible user requirements for the following functions:■ The cash-dispensing function in a bank ATM■ The spelling-check and correcting function in a word processor■ An unattended petrol (gas)
Draw a sequence diagram showing the actions performed in the ticket-issuing system. You may make any reasonable assumptions about the system. Pay particular attention to specifying user errors.
Rewrite the above description using the structured approach described in this chapter.Resolve the identified ambiguities in some appropriate way.
Discover ambiguities or omissions in the following statement of requirements for part of a ticket-issuing system.An automated ticket-issuing system sells rail tickets. Users select their destination and input a credit card and a personal identification number. The rail ticket is issued and their
Discuss the problems of using natural language for defining user and system requirements, and show, using small examples, how structuring natural language into forms can help avoid some of these difficulties.
Identify and briefly describe four types of requirements that may be defined for a computerbased system
As a programmer, you are offered a promotion to project management but you feel that you can make a more effective contribution in a technical rather than a managerial role. Discuss whether you should accept the promotion.
You are asked by your manager to deliver software to a schedule that you know can only be met by asking your project team to work unpaid overtime. All team members have young children. Discuss whether you should accept this demand from your manager or whether you should persuade your team to give
Fixed-price contracts, where the contractor bids a fixed price to complete a system development, may be used to move project risk from client to contractor. If anything goes wrong, the contractor has to pay. Suggest how the use of such contracts may increase the likelihood that product risks will
In addition to the risks shown in Figure 5.11, identify six other possible risks that could arise in software projects.
Using reported instances of project problems in the literature, list management difficulties that occurred in these failed programming projects. (I suggest that you start with Brooks’s book, as suggested in Further Reading.)
Figure 5.5 gives task durations for software project activities. Assume that a serious, unanticipated setback occurs and instead of taking 10 days, task T5 takes 40 days. Revise the activity chart accordingly, highlighting the new critical path. Draw up new bar charts showing how the project might
Figure 5.15 sets out a number of activities, durations and dependencies. Draw an activity chart and a bar chart showing the project schedule.
What is the critical distinction between a milestone and a deliverable?
Briefly explain the purpose of each of the sections in a software project plan.
Explain why the process of project planning is iterative and why a plan must be continually reviewed during a software project.
Explain why the best programmers do not always make the best software managers. You may find it helpful to base your answer on the list of management activities in Section 5.1.
Explain why the intangibility of software systems poses special problems for software project management.
Historically, the introduction of technology has caused profound changes in the labour market and, temporarily at least, displaced people from jobs. Discuss whether the introduction of advanced CASE technology is likely to have the same consequences for software engineers. If you don’t think it
Survey the tool availability in your local development environment and classify the tools according to the parameters (function, activity, breadth of support) suggested here.
Suggest how a CASE technology classification scheme may be helpful to managers responsible for CASE system procurement.
Explain why a software system that is used in a real-world environment must change or become progressively less useful.
Design a process model for running system tests and recording their results.
What are the five components of a design method? Take any method you know and describe its components. Assess the completeness of the method that you have chosen.
Describe the main activities in the software design process and the outputs of these activities. Using a diagram, show possible relationships between the outputs of these activities.
Suggest why it is important to make a distinction between developing the user requirements and developing system requirements in the requirements engineering process.
What are the advantages of providing static and dynamic views of the software process as in the Rational Unified Process?
Explain how both the waterfall model of the software process and the prototyping model can be accommodated in the spiral process model.
Explain why programs that are developed using evolutionary development are likely to be difficult to maintain.
Giving reasons for your answer based on the type of system being developed, suggest the most appropriate generic software process model that might be used as a basis for managing the development of the following systems:■ A system to control anti-lock braking in a car■ A virtual reality system
As an expert in computer security, you have been approached by an organisation that campaigns for the rights of torture victims and have been asked to help the organisation gain unauthorised access to the computer systems of an American company. This will help them confirm or deny that this company
Is it ethical for an engineer to agree to deliver a software system with known faults to a customer? Does it make any difference if the customer is told of the existence of these faults in advance? Would it be reasonable to make claims about the reliability of the software in such circumstances?
In computer security terms, explain the differences between an attack and a threat.
Explain why there is a close relationship between system availability and system security.
In a medical system that is designed to deliver radiation to treat tumours, suggest one hazard that may arise and propose one software feature that may be used to ensure that the identified hazard does not result in an accident.
Reliability and safety are related but distinct dependability attributes. Describe the most important distinction between these attributes and explain why it is possible for a reliable system to be unsafe and vice versa.
Identify six consumer products that contain, or that may contain in the future, safety-critical software systems.
Giving reasons for your answer, suggest which dependability attributes are likely to be most critical for the following systems:■ An Internet server provided by an ISP with thousands of customers■ A computer-controlled scalpel used in keyhole surgery■ A directional control system used in a

Showing 400 - 500 of 3990

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Last

Software Engineering 8th Edition Ian Sommerville - Solutions

Step by Step Answers