OPMAN

• Planning is a formalization of what is intended to happen at the future and does not require that an event will actually happen.
• Plans are based on expectations.
• Push control is a centralized system whereby control and sometimes planning decisions are issued to work centers which are then required to do the task and then supply the next work station.
• In manufacturing, pull schedules generally have far fewer inventory levels than push control.
• Control is the process of coping with the changes and may mean that plans need to be re-drawn in the short-term or an intervention will need to be made in the operation to bring it back.
• Long-term planning and control uses aggregated demand forecasts, determines resources in aggregated form, and sets objectives in largely financial terms.
• Medium-term planning and control uses partially disaggregated demand forecasts, determines resources and contingencies, and sets objectives in both financial and operations terms.
• Short-term planning and control uses totally disaggregated forecasts or actual demand, makes interventions to resources to correct deviations from plans, and considers operations objectives on an ad hoc basis.
• Uncertainty in supply and demand makes planning and control more difficult.
• The degree of uncertainty in demand affects the balance, the greater the uncertainty, the more difficult it is to plan and greater emphasis must be placed on control.
• Dependent demand is the demand that is relatively predictable because it is dependent upon some known factors.
• Independent demand is the demand that is less predictable because it depends on the changes of the market or customer behavior.
• Inventory planning and control is typical and normal of independent planning and control.
• A support service, such as a printing unit, often asks when copies are required and sequences the work according to that due date.
• Last in first out (LIFO) is a method of sequencing usually selected for practical reasons.
• Last in first out - Patients at hospital clinics may be infuriated if they see newly arrived patients examined first.
• First in first out (FIFO) is called first in first out sequencing (FIFO), or sometimes ‘first come, first served’ (FCFS).
• Longest operation time (LOT) involves ordering the jobs by descending order of their processing time, such that the job with the longest processing time is first.
• Shortest operation time first (SOT) involves processing the job with the shortest processing time first.
• All five performance objectives, or some variant of them, can be used to judge the effectiveness of sequencing rules.
• Dependability, speed and cost are particularly important objectives in scheduling.
• Schedules are familiar statements of volume and timing in many consumer environments.
• The scheduling activity is one of the most complex tasks in operations management.
• Schedulers must deal with several different types of resource simultaneously, including machines with different capabilities and capacities, and staff with different skills.
• The number of possible schedules increases rapidly as the number of activities and processes increases.
• Forward scheduling involves starting work as soon as it arrives.
• Backward scheduling involves starting jobs at the last possible moment to prevent them from being late.
• Gantt charts are a simple device which represents time as a bar, or channel, on a chart.
• The start and finish times for activities can be indicated on the chart and sometimes the actual progress of the job is also indicated.
• Pull control is a term used in planning and control to indicate that a work station request a work from the previous station only when it is required.
• Some operations produce products only when they are demanded by specific customers.
• Operations that might be confident of the nature of demand have stocks of resources required to satisfy its customers.
• It would make the actual product or service only to a firm customer order (booking)
• Just In Time or Make to Order is a production strategy where products are manufactured only when there is an order.
• Just In Case or Make to Stock is a production strategy where products are manufactured in advance of orders.
• Low Inventories is a strategy where inventories are kept at a minimum.
• Less Waste is a strategy where waste is minimized.
• Better Communication is a strategy where communication is improved.
• Planning and control activities include loading, sequencing, scheduling, and monitoring and control.
• Loading is the amount of work that is allocated to a work center.