系统工程

Chapter 3
Operation Planning and Control
What is Operation Planning and Control?
Operation Planning and Control are management’s way of providing the necessary direction and capability to manufacturing to achieve sustained profitable performance.
• Defining the product structure an specifications • Assessing each component’s manufacturability • Listing the different processes capable to
manufacturing the component
Input
System performance Output
Feedback
Character of closed-loop system:
• Aware of and influenced by its own past performance • Results of past action influences future action • Senses its performances and automatically makes
2. Operations Planning
Input: • the primary input to the operation planning function is from
demand forecasting. • Another large and important set of input data comes from
• Evaluating the cost of each of the alternative processes
• determining the sequence in which the operations are to be performed
• documenting the process
Inventory Planning: • Input: approved operationhs plan from operations planning • Output: time-phased requirements for components,parts, raw
2.5.2 System Engineering vs. Other Engineering Disciplines
• other engineering disciplines concentrate on using knowledge of the real world (e.g., electrical circuits, materials, robotics),
engineering and concerns new products, modifications to existing products, or modifications to the production process. • A third input, from financial control, concerns monetary constrains and budget limitations. Output: There are two outputs • the total life cycle of a product line and the impact on production and resource capacities of proposed new or modified products; • allocation of available resources to production requirements, machine groupings, facility layout
w of Operation Planning and Control
1. Demand Forecasting Input: 1) Demand histories of existing products and trade information. Demand trends can be determined quantitatively both for one’s own company and for the entire industry. 2) An attempt must be made to anticipate variations in the demand pattern that result from advertising and promotion schemes. 3) External economic factors
Physical vs. Abstract Systems Open vs. Closed system
3.Feedback Control in System 2.4.1 The open-loop system
Input
System Performance
Output
Character of open-loop system:
SystemEngineering
Chapter 1
Introduction to System Engineering
Concept of System
1.1 two level of system Industrial and System engineers design systems at two levels:
adjustments
2.4.3 Feedback
Feedback can be defined as the system function that obtains data on system performance (output), compares the actual performance to the desired performance (a standard or a criterion) and determines the modifications (corrective action) necessary prior to the next execution of system performance.
• Components are simply the individual parts, or elements, that collectively make up a system.
• Relationships are the cause-effect dependencies between components.
3. Inventory Planning and Control
Inventory planning determines the material requirements: components, parts, raw materials, and so on
inventory control determines the proper inventory levels, reorder points, safety stocks, and the like.
• Not aware of its own performance • Past action has no influence on future action • Possesses no means to provide for its own control or
modification
2.4.2 The closed-loop system
3.1 Process Engineering
Process Engineering is concerned with the design of the actual process to be used in the manufacture of the product.
six-step sequence
Output:
1) Expected demand quantities for the several products over some planning period
2)Another important but often overlooked output ：declining demand for a product.-product innovation
• The objective or purpose of a system is the desired state or outcome which the system is attempting to achieve.
2.2 System Classifications
• Natural vs. Man-made System • Static vs. Dynamic Systems
2. System Definition
A system may be defined as a set of components which are related by some form of interaction, and which act together to achieve some objective or purpose
• systems engineering focuses on methods to solve problems, not the solution of the problems.