Chapter 4. Preliminary System Design

1. Chapter 4. Preliminary System Design • It is also known as advance development • It extends the translation of system level requirement into design requirements for the sub system level

2. The Functional Analysis Process • Functional analysis is the iterative process of breaking down requirements from the system level to the sub system • FA reflects the “what” that must be accomplished to achieve objective & goal • Conversion to “how” is accomplished by evaluating each individual block, defining the necessary “inputs” & expand “outputs”

3. Identify need & determine system requirement Design and Develop system Manufacture System Operate and maintain system Control/Constraints Technical Political Sociological Economic Environmental System/product ready supporting resources waste System requirement organizational stru. Raw material Data/documentation Function Output Input HR Material/liquid Computer resources Facilities Maintenance and support Mechanisms Identification of Resources Requirements

4. Requirement Allocation • Fig. 4.6 page 81

5. Design Requirements • Compatible with the system operational requirements and maintenance • Comply with the allocated design criteria • Meet all specification requirements

6. Design Requirements(Parameters) • Design for functional capability- concerns with chemical,electrical, mechanical design etc • capability derives from the characteristic of design that relates to the functional performance of the system (factors-size, shape, volume • Design for reliability- objective is maximize operational reliability and minimize the failure • reliability (R) is often expressed as probability of success

7. Design Requirements(Parameters) • Design for maintainability • characteristic of design & installation that reflect the ease, accuracy and safety • it can be measured in terms of maintenance time • minimize the logistic support resources • Design for usability and safety • concerned with the interfaces between human & HW, SW etc • consideration must include human sensory, physiological, minimize the number of people and skill requirement, minimize training and maximize productivity

8. Design Requirements(Parameters) • Design for supportability/serviceability • ensure that system can ultimately be serviced and support effectively/efficiently through out planned cycle time • includes an application of reliability, maintainability and human factor in design • Design for producibility and disposability • characteristic of design that pertains to the ease and economy of producing system/products • using flexible and economical methods • utilization of standard parts • allows for the disassembly and disposal of elements or components of the system easily/rapidly changes

9. Design Requirements(Parameters) • Design for affordability • characteristic of design and installation that impact budget constraints • objective is to base design decision on life cycle cost not just system acquisition • economic feasibility on the balanced incorporation of reliability, maintainability, human factor, supportability