MOCK 4 QUESTIONS
CPA PART III
SYSTEM THEORY AND IFORMATION COMMUNICATION TECHNOLOGY
Time Allowed: 3 hours
Answer any FIVE questions. Marks allocated to each question are shown at the end of the question.
QUESTION ONE
Kasuku Engineering Co. Ltd, a company that is involved in the design and manufacturing of various products realizes that, in order to remain ahead of its competitors, it must introduce Computer Aided Design (CAD) techniques. Required:
- Define what is meant by ‗Computer Assisted Design‘ techniques. (2 marks)
- List and describe briefly FOUR potential benefits, the company is likely to experience in the adoption of CAD. (8 marks) c) List five physical security procedures that Kasuku might adopt to make sure that its
information is secure. (10 marks)
(Total: 20 marks)
QUESTION ONE
- Computer Aided Design (CAD) techniques These refer to techniques that automate the creation and revision of designs using sophisticated graphics software.
- Potential benefits:
- Quality designs. CAD ensures accuracy in the production of designs. CAD alsosubjects designs to rigorous testing thus ensuring reliability.
- Speed in designing. Since the design process is automated, it‘s likely to be shorterthan manual design.
- Improved group collaboration. CAD enables sharing of designs amongst manydesigners thus improving group collaboration.
- Reduced costs
Using a traditional physical design methodology, each design modification requires a mold to be made and a prototype to be physically tested. This process must be repeated many times, which is very expensive and time consuming. Using a CAD workstation, the designer only needs to make a physical prototype toward the end of the design process because the design can be easily tested and changed on the computer.
- Physical security procedures that may be adopted:
- Bolting door locks –These require the traditional metal key to gain entry. The keyshould be stamped ‗Do not duplicate.‘
- Combination door locks –These utilize a numeric keypad or dial to gain entry.The combination should be changed at regular intervals or whenever an employee with
access is transferred, fired or subject to disciplinary action.
- Electronic door locks –These utilize a magnetic or embedded chip-based plasticcard key or token entered into a sensor card reader to gain access. A special code internally stored in the card or token is read by the sensor device that activates the door locking mechanism.
- Biometric door locks – An individual‘s unique body features, such as voice, retina,fingerprint or signature, activate these locks.
- Manual logging – All visitors should be required to sign a visitor‘s log indicatingtheir name, company represented, reason for visiting and person to see.
Logging should be at the front reception desk and at the entrance to the computer room.
- Electronic logging –All access should be logged with unsuccessful
- Identification Badges (Photo Ids)–Badges should be worn and displayed by allpersonnel. Visitor badges should be a different colour from employee badges for
easy identification.
- Video cameras –They should be located at strategic points and monitored by security guards.
- Security guards –They could be used together with video cameras for efficiency.
- Controlled visitor access –All visitors should be escorted by a
- Alarm systems –should be linked to inactive entry points, motion detectors and the reverse flow of enter or exit only doors.
- Controlled single entry point. A controlled single entry point monitored by are ceptionist should be used by all incoming personnel. QUESTION TWOIn data communication, the communication channel is the route along which data is transmitted. The transmission of data can be described by the following four characteristics:
- Direction of flow of data.
- Communication lines.
- Speed of data transmission. D. Mode of data transmission.
Required:
For each of the following data communication concepts/devices, indicate under which ONE of the above listed characteristics A-D they would best fall:
- Protocol; iii. Half duplex; iv. Fibre optics; v. Simplex; vi. Analog signal; vii. Micro wave; viii. Band width; ix. Start/stop bit;
- Voice bad. (10 marks)
Explain the term internetworking within the context of data communication. (5 marks) How does a call-back unit and data-encryption equipment enhance security in a computer network?
(5 marks)
( Total: 20 marks)
QUESTION TWO
- a) (i) Protocol – D
- Half duplex – A
- Fibre optics – B
- Simplex – A
- Analog signal – D
- Microwave – B
- Bandwidth – C
- Start/Stop bit – D
- Asynchronous – D
- Voice Band -B
- Internetworking
This refers to the linking of separate networks, each of which retains its own identity, into an inter-connected network. An interconnected network may consist of an organizational network linked to other organizational networks, to the Internet, to the networks of public telecommunication service providers or to other public networks via a backbone.
- Call-back unit
When a terminal requests for access to another terminal and authenticates itself, the callback mechanism interrupts the telecommunications dial-up connection to the other
terminal by dialing back the caller (requesting terminal) to validate the terminal‘s identity.Call-back units thus prevent terminals from masquerading i.e. falsifying their identities so as to gain additional privileges or access to otherwise forbidden data or systems.
Data Encryption Equipment
These enable data encryption i.e. the process of converting data (plain text) into a secure coded form (cipher text) that cannot be understood without converting back via decryption (the reverse process) to plain text again. Messages can thus be encrypted before they are sent to prevent eavesdropping on messages in transit in a network. Data encryption could also be used to protect data stored on servers from disclosure to intruders (unauthorized users) who have already gained access to the server.
QUESTION THREE a) Microprocessor
This refers to a semiconductor chip that integrates all of the memory, logic and control circuits for an entire Central Processing Unit of a computer onto a single chip. Microprocessors come in the form of a Silicon chip mounted on an electronic circuit board. The semiconductor chip that constitutes a microprocessor consists of thousands of transistors. The transistors operate as electronic switches each having two binary
states (ON or OFF). Examples of microprocessors common in today‘s market are the Intel Pentium III chip and the Intel Pentium IV chip.
Distributed data processing
This refers to a mode of processing that distributes the computer processing work among multiple computers linked by a communication network. A common example of distributed processing is client/server computing which splits processing between clients and servers. Both are on the network, but each machine is assigned functions it is best suited to perform. The client is the point of entry for the required function. The server provides the client with services e.g. storage and processing of data, and also management of network activities.
Direct Access backing storage
Backing storage refers to that which supplements the main memory. A direct access backing storage device is one that allows for data to be retrieved by going to the exact position of the data without following any order. This mode of access is made possible because each location on the storage medium has a unique address and thus the read/write head can go directly to the required location. Examples of direct access backing storage devices are magnetic disks (Hard disks and floppy disks).
Batch processing
This refers to a mode of processing data in which transactions are accumulated and stored until a specified time when it is convenient or necessary to process them as a group. An example of a batch processing system is a payroll system.
Time sharing
This refers to the sharing of computer resources by many users simultaneously by having the
CPU spend a fixed amount of time on each user‘s program before proceeding to the next. Thousands of users are each allocated a tiny slice of computer time, when each is required to perform any operation. At the end of this period, another user is given another time slice of the CPU. Time-sharing is facilitated by most modern operating systems.
QUESTION THREE
Explain the following:
- (a) Microprocessor.(b) Distributed data processing.
( c) Direct access backing storage. Give examples.
- Batch processing.
- Time sharing. (20 marks) QUESTION THREE a) MicroprocessorThis refers to a semiconductor chip that integrates all of the memory, logic and control circuits for an entire Central Processing Unit of a computer onto a single chip. Microprocessors come in the form of a Silicon chip mounted on an electronic circuit board. The semiconductor chip that constitutes a microprocessor consists of thousands of transistors. The transistors operate as electronic switches each having two binarystates (ON or OFF). Examples of microprocessors common in today‘s market are theIntel Pentium III chip and the Intel Pentium IV chip.
Distributed data processing
This refers to a mode of processing that distributes the computer processing work among multiple computers linked by a communication network. A common example of distributed processing is client/server computing which splits processing between clients and servers. Both are on the network, but each machine is assigned functions it is best suited to perform. The client is the point of entry for the required function. The server provides the client with services e.g. storage and processing of data, and also management of network activities.
Direct Access backing storage
Backing storage refers to that which supplements the main memory. A direct access backing storage device is one that allows for data to be retrieved by going to the exact position of the data without following any order. This mode of access is made possible because each location on the storage medium has a unique address and thus the read/write head can go directly to the required location. Examples of direct access backing storage devices are magnetic disks (Hard disks and floppy disks).
Batch processing
This refers to a mode of processing data in which transactions are accumulated and stored until a specified time when it is convenient or necessary to process them as a group. An example of a batch processing system is a payroll system.
Time sharing
This refers to the sharing of computer resources by many users simultaneously by having the
CPU spend a fixed amount of time on each user‘s program before proceeding to the next. Thousands of users are each allocated a tiny slice of computer time, when each is required to perform any operation. At the end of this period, another user is given another time slice of the CPU. Time-sharing is facilitated by most modern operating systems QUESTION FOUR
The introduction of a computer-based information system in an organization can generate some amount of fear and reluctance to change on the part of users.
Required:
- List six major reasons for such user resistance.
For each reason, provide a brief explanation. (12 marks)
- How can this problem of user resistance to change be solved?(8 marks)
(Total: 20 marks)
QUESTION FOUR
- a) Reasons for user resistance:
- Parochial Self-Interests
Users may resist a computer-based information system because they may perceive it as a threat to their current job, power, etc 2. Differing Perceptions Or Assessments
Managers could view the computer-based system as vital to organizational efficiency while operations staff may view a computer-based system as a nuisance to their normal
operations thus leading to their resistance to the system.
- Ignorance
Users could resist the introduction of a computer-based information system due to lack of knowledge of the potential benefits of the system.
- Mistrust And Suspicion
Users could view the computerization of the information system as an opportunity for downsizing the labour force and thus they will tend to resist.
- Lack of Involvement of Users in the Computerization Initiative.
When users are not involved, they feel left out and thus they resist in protest to management.
- Need To Re-skill
The need to re-skill due to the introduction of the computer based information system may discourage users particularly when some of them feel that they won‘t be able to cope with the new demands due to their age.
- b) Probable solutions to the problem of user resistance:
- User Involvement And Participation In The Change Users could be involved in the design and implementation of a project so as to make them feel that they have a stake in the project. 2. Communication and Education
The users need to understand the need for change as well as the logic behind it.
- Facilitation And Support Of The Change Support from management in the form of specialized training, job-stress counseling, and compensatory time offs could be used to reduce the negative effects of the change. 4. Negotiation And Agreement.
Management could negotiate with user representatives and offer them incentives such as promotions in exchange for their cooperation in the change.
- Manipulation And Cooptation
Manipulation occurs when the management holds back information and consciously events to increase chances of success of a change. Cooptation involves token participation. Those who are co-opted cannot claim that they haven‘t been consulted yet
the ultimate impact of their input is negligible.
- Explicit And Implicit Coercion
Management could force the change through coercive means e.g. salary reduction and job losses. This technique is used where speed is essential and the change initiators possess considerable powers. This technique is recommended as the last alternative to dealing with user resistance.
QUESTION FIVE
Distinguish between the following pairs of terms:
(a) A closed system and an open system.
( b) A deterministic and a random system.
- An open-loop system and a closed-loop system.
- A human system and a machine system.
(20 marks)
QUESTION FIVE
- a) Closed system
This system has no interaction with the environment. It neither transmits information to the outside world nor receives any information from the outside world. It‘s mainly a scientific concept e.g. Physics experiments.
Open System
This system interacts with its environment. It is a system with a feedback mechanism that promotes free exchange of information between the system and the external entities.
Organizations are good examples of open systems. b) Deterministic system
They operate in a predictable manner e.g. thermostats and computer programs.
Probabilistic Systems/Random Systems
With these systems, it‘s not possible to determine the next state of the system even if the current state is known. An example is a doctor‘s diagnostic system.
- Open -loop system This refers to a system that does not act in a controlled manner, that is, there is no feedback loop, and so no measure of performance against standards.
CLOSED -LOOP SYSTEM
This refers to a system that functions in a controlled manner. Such a system accepts inputs, works on them according to some predefined processing roles and produces outputs. Such a system is controlled via a feedback loop.
- Human system
This refers to a system that is composed of human beings. An example is a soccer team.
MACHINE SYSTEM
This refers to a system that is of mechanical components e.g. gears, propellers, exhaust pipe, etc. A good example of a machine system is a car engine
QUESTION SIX
Accompanying the use of computerized operations in a business are a host of means by which fraud can be committed. This has given rise to various counter measures to enhance security of computer systems.
Required:
- List six methods and tools that are useful in stemming computer fraud by employees.
(12 marks)
- Explain how theft of computer time by employees (unauthorized use of the firm‘s computer) can be minimized. (8 marks)
(Total: 20 marks)
QUESTION SIX
- Computer fraud arises when a person gains access to or uses a computer program or data
or computer to deceive or defraud others.
Methods and tools that are useful in stemming computer fraud by employees:
- Strict division of duties –Eases supervision/monitoring.
- Strict control over input, processing, and programs.
- Shielding Visual Display Units to prevent people with detection equipment that isable to remotely view what is being displayed on the VDU. 4. Use of logon-Ids and passwords to prevent unauthorized access.
- Logging computer access –Review of the security logs could identify patterns ortrends that indicate computer fraud.
- Biometric access security control.
- Dial-back procedures.
- Video cameras to enable detection of physical unauthorized access.
- Security guards to prevent physical unauthorized access.
- Alarm system to prevent physical unauthorized access, etc.
- How theft of computer time may be minimized:
- Logging of access –This would enable the organization to identify instances wherecomputer resources were used without authorization and take appropriate
- Electronic door lock access systems, which are capable of denying access to andindividual depending on the current time. These ensure that employees do not use
computer rooms outside work hours.
- Security guards. The guards could be instructed to deny employees entry to thefirm‘s premises outside working hours.
- Automatic log-off systems.These automatically log-off the user when the allocatedtime has expired or when a user is trying to gain access outside the allocated computer usage times.
- Usernames and passwords could be granted to authorized employees thuspreventing unauthorized employees from using an organization‘s computers.
- Controlled single entry points to computer rooms.A controlled entry pointmonitored by a receptionist should be used by all incoming personnel. In this way, the receptionist could be used to monitor the employees accessing the computers and the times in which access is taking place.
QUESTION SEVEN
(a) Distinguish between a system flowchart and a program flow chart. (6 marks)
( b) The payroll system for a company is given in the narrative below:
―When a person is hired, the company manager prepares an employment form and deductions slip. These are forwarded to the payroll clerk. Each week employees hand in timecards showing hours worked to the payroll clerk. Every four weeks the payroll clerk completes earnings and deductions for each employee and payroll taxes for the company. This detailed information is then forwarded to the cash disbursements clerk who:
- Prepares the pay cheque.
- Enters the payroll transactions in the cash disbursements journal.
- Sends pay cheques back to the payroll clerk.
Employees year-to-date earnings and deductions are then updated by the payroll clerk and cheques distributed to the employees.‖
Required:
Draw a system flowchart for the payroll system described above. (14 marks)
(Total: 20 marks)
QUESTION SEVEN
- a) System flow chart
This describes the data flow for a data processing system. It provides a logical diagram of how the system operates. It represents the flow of documents and the operations performed in a data processing system. A system flowchart also reflects the relationships
between inputs, processing and outputs.
Program flow chart
It represents in detail, the various steps to be performed within the system for transforming the input into output. The various steps are logical/arithmetic operations, algorithms, etc. Program flowcharts serve as the basis for discussions and communication between the system analysts and programmers. Program flowcharts are quite helpful to programmers in organizing their programming efforts. These flow charts constitute an important component of documentation for an application.
- b) A probable system flowchart for the payroll system: Diagramming convention used – NCC convention. NCC system flowchart symbols:
Document, report or form.
Operation or task
Data flow
Data store or file
Decision
QUESTION EIGHT
- (i.) What is a Decision Support System (DSS)? (ii.) Describe the major DSS software components. (10 marks)
- (i.) What is an expert system?
(ii.) List four advantages of using an Expert System in decision making. (10 marks)
QUESTION EIGHT
- a) (i) Decision Support System (DSS)
These are information systems that support managers in day-to-day decision-making and most of them are used in semi-structured problems. DSSs emphasize on small simple models, which can be easily understood and used by mangers rather than complex integrated systems which need information system specialists to operate. They cut across both data support and transaction processing.
(ii) DSS software components:
3 main components:
- The data management subsystem (the database)
- The dialogue/use interface subsystem 3. The model management subsystem
DATA MANAGEMENT MODEL MANAGEMENT Diagram:
The dialogue model is basically a user interface at which the user enters data into the system or views data from the system.
The data management component consists of current or historical data from a number of applications or groups. It may be in the form of a small database residing on a PC that contains a subset of corporate data that has been downloaded and possibly combined with external data. Alternatively, the DSS database may be a massive data warehouse that is continuously updated by major organizational transaction processing systems (including enterprise systems and data generated by website transactions). The data in DSS databases are generally extracts or copies of production databases so that using the DSS does not interfere with critical operational systems.
The model management component consists of a system that maps data to models in order to produce results that could be used to support decision-making. A model is and abstract representation that illustrates the components or relationships that illustrates the components or relationships of a phenomenon. A model could be a physical one (such as a model airplane), a mathematical one (such as an equation) or a verbal one (such as a description of a procedure for writing and order).
- b) (i) Expert system
This is a knowledge-intensive computer program that captures the expertise of a human in limited domains of knowledge. An expert system could assist decisionmaking in an organization by asking relevant questions and explaining the reasons for adopting certain actions.
(ii) Advantages of expert systems in decision-making:
- Enable high quality decisions to be made.
- They reduce the number of decision makers since they partly automate the process of decision-making. This implies lower labour costs.
- They ensure accountability since they provide reasons for proposing an action.
- Since they support managers in decision-making, they enable decisions to be made within a short time period.
Since expert systems capture human expertise, they enable organizations to fully retain intellectual resources for future decision-making
