Operations Management Chapter 15 – Short-Term Scheduling PowerPoint presentation to accompany Heizer/Render Principles of Operations Management, 7e Operations Management, 9e © 2008 Prentice Hall, Inc 15 – Outline Global Company Profile: Delta Air Lines The Strategic Importance of ShortTerm Scheduling Scheduling Issues Forward and Backward Scheduling Scheduling Criteria © 2008 Prentice Hall, Inc 15 – Outline – Continued Scheduling Process-Focused Facilities Loading Jobs Input-Output Control Gantt Charts Assignment Method © 2008 Prentice Hall, Inc 15 – Outline – Continued Sequencing Jobs Priority Rules for Dispatching Jobs Critical Ratio Sequencing N Jobs on Two Machines: Johnson’s Rule Limitations of Rule-Based Dispatching Systems Finite Capacity Scheduling (FCS) © 2008 Prentice Hall, Inc 15 – Outline – Continued Theory of Constraints Bottlenecks Drum, Buffer, Rope Scheduling Repetitive Facilities Scheduling Services Scheduling Service Employees with Cyclical Scheduling © 2008 Prentice Hall, Inc 15 – Learning Objectives When you complete this chapter you should be able to: Explain the relationship between shortterm scheduling, capacity planning, aggregate planning, and a master schedule Draw Gantt loading and scheduling charts Apply the assignment method for loading jobs © 2008 Prentice Hall, Inc 15 – Learning Objectives When you complete this chapter you should be able to: Name and describe each of the priority sequencing rules Use Johnson’s rule Define finite capacity scheduling List the steps in the theory of constraints Use the cyclical scheduling technique © 2008 Prentice Hall, Inc 15 – Delta Airlines About 10% of Delta’s flights are disrupted per year, half because of weather Cost is $440 million in lost revenue, overtime pay, food and lodging vouchers The $33 million Operations Control Center adjusts to changes and keeps flights flowing Saves Delta $35 million per year © 2008 Prentice Hall, Inc 15 – Strategic Importance of Short-Term Scheduling Effective and efficient scheduling can be a competitive advantage Faster movement of goods through a facility means better use of assets and lower costs Additional capacity resulting from faster throughput improves customer service through faster delivery Good schedules result in more dependable deliveries © 2008 Prentice Hall, Inc 15 – Scheduling Issues Scheduling deals with the timing of operations The task is the allocation and prioritization of demand Significant issues are The type of scheduling, forward or backward The criteria for priorities © 2008 Prentice Hall, Inc 15 – 10 Scheduling Repetitive Facilities Advantages include: Lower inventory levels Faster product throughput Improved component quality Reduced floor-space requirements Improved communications Smoother production process © 2008 Prentice Hall, Inc 15 – 65 Scheduling Services Service systems differ from manufacturing Manufacturing Schedules machines and materials Inventories used to smooth demand Machine-intensive and demand may be smooth Scheduling may be bound by union contracts Few social or behavioral issues © 2008 Prentice Hall, Inc Services Schedule staff Seldom maintain inventories Labor-intensive and demand may be variable Legal issues may constrain flexible scheduling Social and behavioral issues may be quite important 15 – 66 Scheduling Services Hospitals have complex scheduling system to handle complex processes and material requirements Banks use a cross-trained and flexible workforce and part-time workers Retail stores use scheduling optimization systems that track sales, transactions, and customer traffic to create work schedules in less time and with improved customer satisfaction © 2008 Prentice Hall, Inc 15 – 67 Scheduling Services Airlines must meet complex FAA and union regulations and often use linear programming to develop optimal schedules 24/7 operations like police/fire departments, emergency hot lines, and mail order businesses use flexible workers and variable schedules, often created using computerized systems © 2008 Prentice Hall, Inc 15 – 68 Demand Management Appointment or reservation systems FCFS sequencing rules Discounts or other promotional schemes When demand management is not feasible, managing capacity through staffing flexibility may be used © 2008 Prentice Hall, Inc 15 – 69 Scheduling Service Employees With Cyclical Scheduling Objective is to meet staffing requirements with the minimum number of workers Schedules need to be smooth and keep personnel happy Many techniques exist from simple algorithms to complex linear programming solutions © 2008 Prentice Hall, Inc 15 – 70 Cyclical Scheduling Example Determine the staffing requirements Identify two consecutive days with the lowest total requirements and assign these as days off Make a new set of requirements subtracting the days worked by the first employee Apply step to the new row Repeat steps and until all requirements have been met © 2008 Prentice Hall, Inc 15 – 71 Cyclical Scheduling Example Employee M T W T F S S 5 3 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 72 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 73 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 74 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Employee 2 2 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 75 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Employee 2 2 Employee 1 2 2 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 76 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Employee 2 2 Employee 1 2 2 Employee 1 1 1 Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 77 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Employee 2 2 Employee 1 2 2 Employee 1 1 1 Employee Capacity (Employees) Excess Capacity © 2008 Prentice Hall, Inc 15 – 78 Cyclical Scheduling Example M T W T F S S Employee 5 3 Employee 4 3 Employee 3 3 Employee 2 2 Employee 1 2 2 Employee 1 1 1 Employee Capacity (Employees) 5 3 Excess Capacity 0 0 © 2008 Prentice Hall, Inc 15 – 79 ... crews, catering, gate, ticketing personnel Table 15. 1 © 2008 Prentice Hall, Inc 15 – 11 Scheduling Flow Figure 15. 1 © 2008 Prentice Hall, Inc 15 – 12 Forward and Backward Scheduling Forward... Output 270 270 270 270 Cumulative Deviation –50 –100 150 –200 –20 –10 +5 Cumulative Change in Backlog Figure 15. 2 © 2008 Prentice Hall, Inc 15 – 22 Input-Output Control Example Work Center DNC... Apply the assignment method for loading jobs © 2008 Prentice Hall, Inc 15 – Learning Objectives When you complete this chapter you should be able to: Name and describe each of the priority sequencing