What is a process: “A network of activities performed by resources that transform inputs into outputs.” Anupindi et. Al. 1999
“A set of logically related tasks or activities performed to achieve a defined business outcome.” APICS Dictionary 1995
“The collection of activities and operations involved in transforming inputs, which are the physical facilities, materials, capital, equipment, people, and energy, into outputs, or the products and services.” Evans & Lindsay 2002
“A collection of activities and decisions that produce an output for an internal or external customer.” Devane, T. 2004
Purpose of processes è create the correct product (greater value than competitors at a profit that provides enough to meet needs of stakeholders in a perceived equable manner) in a given context
Context: market demand, market share, technology (machines, computers, software) and resources (knowledge, materials, people, infrastructure, power) available to execute process
How to judge a process:
How well does it meet demand (step one queue if tied to arrival of orders, capacity, Takt time, cycle time, business rules)
How well does the process utilize and treate resources (utilization (people and machine, rate of consumption of power), WIP (holding/queue or process, or total), power, pollution, safety, material)
How well does it produce the customer described/demanded product
Cost relative to achievable price
Why & how to simulate
i) Existing: To learn about the process and to do what if analysis
(a) conceptual model,
(b) data flow,
(c) resources (costs),
(d) demand,
(e) interfaces,
(f) business rules,
(g) collect data from observation
- arrival rate, demand, step cycle times, TPT (use for verification), capacity (use for verification), batch size, set up costs, resource costs, mean time to break down/chance of breakdown, time down, scrap, rework, items produced per step,
(h) Enter into simulator
(i) Verify data and model (does the model produce the same results every time as expected (costs and output))
(j) Validate the model (does the model mimic the real outputs of the actual process)
(k) Do what if analysis, including statistics
ii) Green Field: To learn about the process and do what if analysis
(a) conceptual model,
(b) data flow,
(c) resources (costs),
(d) demand,
(e) interfaces,
(f) business rules,
(g) collect data from projections
(h) arrival rate, demand, step cycle times, TPT (use for verification), capacity (use for verification), batch size, set up costs, resource costs, mean time to break down/chance of breakdown, time down, scrap, rework, items produced per step
(i) Enter into simulator
(j) Verify data and model (does the model produce the same results with simple data as mathematically solving the model)
(k) Do what if analysis, including statistics