Simulation Applications In Logistics And Transportation


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Discrete Event Simulation Applications in Validating / Designing Logistics & Transportation Network

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Simulation Applications In Logistics And Transportation

  1. 1. Simulation Applications in Logistics & Transportation systems
  2. 2. Contents 1. Introduction to Logistics & Transportation Systems 2. Classification of Logistics & Transportation Simulation models 3. Inputs / Outputs of the Simulation Model
  3. 3. Introduction <ul><ul><li>Definition : Logistics & Transport (L&T) can be defined as a network composed of one or more terminals / hubs connected by a set of traffic lanes </li></ul></ul><ul><li>Major elements of L&T system : </li></ul><ul><li>Direct Resources : Resources used in physical transportation of freight (goods) from one geographical location to another </li></ul><ul><li>e.g.: Trucks, Aircrafts, Cargo Ships, Drivers, Pilots etc. </li></ul><ul><li>Indirect Resources : Resources used in sorting, storing, handling, retrieving and consolidating at the various transit locations </li></ul><ul><li>e.g.: Forklifts, Docks, Carts, Storage-bins and Racks inside warehouse etc. </li></ul>
  4. 4. <ul><ul><li>Direct (moving) and Indirect resources must operate together in the most efficient manner for smooth and balanced operation of L&T network. Which would reduce amount of delays at hubs / Maximum availability & utilization of resources / On time pick-up and delivery of physical goods </li></ul></ul><ul><li>Right Part at the Right Place at the Right Time </li></ul>
  5. 5. Classification of Logistics & Transportation Simulation models
  6. 6. <ul><li>Simulation models in L&T are built for the following purposes: </li></ul><ul><ul><li>Models for strategic planning </li></ul></ul><ul><ul><li>Models for tactical planning </li></ul></ul><ul><ul><li>Models for network/traffic control: </li></ul></ul><ul><ul><ul><ul><li>Offline control </li></ul></ul></ul></ul><ul><ul><li>Models for scheduling and dispatching: </li></ul></ul><ul><ul><ul><ul><li>Off-line scheduling </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Exception handling </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Real-time monitoring </li></ul></ul></ul></ul>Classification of simulation models
  7. 7. <ul><li>L&T Problems appropriate for simulation studies are divided into three major categories: </li></ul><ul><ul><li>New design </li></ul></ul><ul><ul><li>Evaluation of alternative designs </li></ul></ul><ul><ul><li>Refinement and redesign of existing operations </li></ul></ul><ul><ul><li>Problems in new design domain are solved generally by optimization / heuristic approaches. Simulation models are often used for validating purposes on case to case basis but not mandatory </li></ul></ul>Classification of simulation models
  8. 8. A. New Design <ul><ul><li>Network design : validation of Hub/Spoke design and Direct move </li></ul></ul><ul><ul><li>Terminal / Hub planning :Identifying No. of terminals, Location, Size (dock dimensions, number of doors) </li></ul></ul><ul><ul><li>Fleet Planning </li></ul></ul><ul><ul><li>Route Planning </li></ul></ul><ul><ul><li>Least- cost transportation modes </li></ul></ul>Simulation works through an iterative approach and does not generate alternatives as such
  9. 9. B. Evaluation of alternative designs <ul><ul><li>Transportation mode alternatives: </li></ul></ul><ul><ul><ul><li>On-the-road (trucks) – Relay / Sleeper </li></ul></ul></ul><ul><ul><ul><li>Rail (trains) : Single / Double stacked </li></ul></ul></ul><ul><ul><ul><li>Air : Planes / Helicopters </li></ul></ul></ul><ul><ul><ul><li>Ocean : Ship / Barges </li></ul></ul></ul><ul><ul><li>Inter-modal alternatives: </li></ul></ul><ul><ul><ul><li>Combine sleeper with rail </li></ul></ul></ul><ul><ul><ul><li>Combine relay with sleeper </li></ul></ul></ul><ul><ul><ul><li>Combine rail with relay </li></ul></ul></ul><ul><ul><ul><li>Combine trucks with air </li></ul></ul></ul><ul><ul><ul><li>Combines trucks/air with ocean </li></ul></ul></ul>
  10. 10. <ul><ul><li>Service performance alternatives: </li></ul></ul><ul><ul><ul><li>Overnight service </li></ul></ul></ul><ul><ul><ul><li>Two – day service </li></ul></ul></ul><ul><ul><ul><li>Premium service </li></ul></ul></ul>B. Evaluation of alternative designs
  11. 11. C. Refinement and redesign of existing operations <ul><ul><li>Operational performance analysis </li></ul></ul><ul><ul><li>On-the-road movements </li></ul></ul><ul><ul><ul><li>Line-haul, regional and group operations </li></ul></ul></ul><ul><ul><ul><li>Terminal operations </li></ul></ul></ul><ul><ul><li>Operating rules </li></ul></ul><ul><ul><ul><li>Hooking, unhooking, hostling and fueling </li></ul></ul></ul><ul><ul><ul><li>Trailer loading and trailer off-loading </li></ul></ul></ul><ul><ul><ul><li>Dock operations </li></ul></ul></ul><ul><ul><ul><li>Dispatching </li></ul></ul></ul>
  12. 12. <ul><ul><li>Rail movements: </li></ul></ul><ul><ul><ul><li>Loading strategies at the rail yard </li></ul></ul></ul><ul><ul><ul><li>Train timetables </li></ul></ul></ul><ul><ul><ul><li>Capacity requirements </li></ul></ul></ul><ul><ul><li>Air transportation: </li></ul></ul><ul><ul><ul><li>Origin terminal operations </li></ul></ul></ul><ul><ul><ul><li>End - of- line operations </li></ul></ul></ul><ul><ul><ul><li>Central / distributed hub operations </li></ul></ul></ul>C. Refinement and redesign of existing operations
  13. 13. 2. Inputs / Outputs of the Simulation Model
  14. 14. <ul><ul><li>Simulation of warehousing and distribution systems </li></ul></ul><ul><ul><li>Simulation of trucking operations </li></ul></ul><ul><ul><li>Simulation of truck docks </li></ul></ul><ul><ul><li>Simulation of ramp operations in air-cargo hubs </li></ul></ul>Case Studies Factors to be considered in each of the case studies: <ul><ul><li>Purpose of building the model </li></ul></ul><ul><ul><li>Entities, resources and critical processes that need special attention </li></ul></ul><ul><ul><li>What- if scenarios </li></ul></ul><ul><ul><li>Input data required </li></ul></ul><ul><ul><li>Output data from simulation </li></ul></ul>
  15. 15. 1. Simulation of warehousing and distribution systems
  16. 16. <ul><li>Purpose of the simulation model: </li></ul><ul><li>To evaluate the performance of individual value adding (indirect) resources,facilities and operations as well as the flow of transportation entities (direct resources) between the plants, warehouses and customers. </li></ul><ul><ul><li>To evaluate strategic decisions </li></ul></ul><ul><ul><ul><li>Warehouse location and allocation </li></ul></ul></ul><ul><ul><ul><li>Warehouse / Distribution center designs </li></ul></ul></ul><ul><ul><ul><li>Transportation mode analysis </li></ul></ul></ul><ul><ul><li>To test tactical solutions </li></ul></ul><ul><ul><ul><li>Inventory management policies </li></ul></ul></ul><ul><ul><ul><li>Pull ordering between customers and plants </li></ul></ul></ul><ul><ul><ul><li>Push ordering between warehouses </li></ul></ul></ul><ul><ul><ul><li>Service levels </li></ul></ul></ul>Simulation of warehousing and distribution systems
  17. 17. <ul><ul><li>To identify operation problems on an ongoing basis </li></ul></ul><ul><ul><ul><li>Changes in transportation modes </li></ul></ul></ul><ul><ul><ul><li>Changes in warehouse operation parameters </li></ul></ul></ul><ul><ul><ul><li>Changes in parts and finished products </li></ul></ul></ul><ul><ul><ul><li>Customer demand fluctuations </li></ul></ul></ul>Simulation of warehousing and distribution systems
  18. 18. <ul><li>Entities: </li></ul><ul><ul><li>Product related entities </li></ul></ul><ul><ul><ul><li>Primary and non primary parts : Produced in-house / Vendor supplied </li></ul></ul></ul><ul><ul><li>Products (Semi-finished / Finished ) </li></ul></ul><ul><ul><li>Palletized Items </li></ul></ul><ul><ul><ul><li>Parts </li></ul></ul></ul><ul><ul><ul><li>Semi- Finished Products </li></ul></ul></ul><ul><ul><ul><li>Finished Products </li></ul></ul></ul><ul><ul><li>Information oriented entities </li></ul></ul><ul><ul><ul><li>Orders from customers </li></ul></ul></ul><ul><ul><ul><li>Orders for shortage </li></ul></ul></ul>Simulation of warehousing and distribution systems
  19. 19. Resources: <ul><ul><li>Trucks </li></ul></ul><ul><ul><ul><li>Between plants and warehouses </li></ul></ul></ul><ul><ul><ul><li>Between warehouses </li></ul></ul></ul><ul><ul><ul><li>Between warehouses and customers </li></ul></ul></ul><ul><ul><li>Airplanes </li></ul></ul><ul><ul><ul><li>Between plants and warehouses </li></ul></ul></ul><ul><ul><ul><li>Between warehouses </li></ul></ul></ul><ul><ul><ul><li>Between warehouses and customers </li></ul></ul></ul>Simulation of warehousing and distribution systems
  20. 20. <ul><ul><li>Ships / Barges </li></ul></ul><ul><ul><ul><li>Between domestic (foreign) plants and foreign (domestic) warehouses </li></ul></ul></ul><ul><ul><ul><li>Between foreign warehouses </li></ul></ul></ul><ul><ul><ul><li>Between domestic (foreign) warehouses and foreign (domestic) customers </li></ul></ul></ul><ul><ul><li>Internal (warehouse / plants / distribution centers / customer sites) equipment </li></ul></ul><ul><ul><ul><li>Forklifts </li></ul></ul></ul><ul><ul><ul><li>Carts </li></ul></ul></ul><ul><ul><ul><li>Pallet Trucks </li></ul></ul></ul><ul><ul><ul><li>Conveyors </li></ul></ul></ul><ul><ul><ul><li>AS/RS Systems </li></ul></ul></ul><ul><ul><ul><li>Guided Vehicles </li></ul></ul></ul>Simulation of warehousing and distribution systems
  21. 21. Processes / Activities: <ul><ul><li>Order processing at the warehouse (manual ,automated ) </li></ul></ul><ul><ul><ul><ul><li>Pull ordering system </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Push ordering system </li></ul></ul></ul></ul><ul><ul><li>Terminal operations at plants, warehouse and customers (domestic/ foreign) </li></ul></ul><ul><ul><li>Grouping / Palletizing </li></ul></ul><ul><ul><ul><ul><li>At a production plant before shipping to a warehouse </li></ul></ul></ul></ul><ul><ul><ul><ul><li>At a warehouse before shipping to a customer </li></ul></ul></ul></ul><ul><ul><li>Ungrouping </li></ul></ul><ul><ul><ul><ul><li>At a warehouse once the parts arrive from a plant </li></ul></ul></ul></ul><ul><ul><li>Transportation mode selection </li></ul></ul><ul><ul><ul><ul><li>At production plants </li></ul></ul></ul></ul><ul><ul><ul><ul><li>At warehouses </li></ul></ul></ul></ul>Simulation of warehousing and distribution systems
  22. 22. <ul><ul><li>Handling shortages (or surplus inventory) </li></ul></ul><ul><ul><ul><ul><li>Creation at a warehouse (domestic / foreign) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Send an order message to another warehouse </li></ul></ul></ul></ul><ul><ul><li>Movement of parts (raw materials, semi-finished) </li></ul></ul><ul><ul><ul><ul><li>From domestic plants to domestic warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From foreign plants to foreign warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From domestic plants to foreign warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From foreign plants to domestic warehouses </li></ul></ul></ul></ul><ul><ul><li>Movement of finished products </li></ul></ul><ul><ul><ul><ul><li>From domestic warehouse to domestic customers </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From foreign warehouse to customers abroad </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Between domestic warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Between foreign warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Between domestic and foreign warehouses </li></ul></ul></ul></ul>Simulation of warehousing and distribution systems
  23. 23. <ul><ul><li>Customer orders </li></ul></ul><ul><ul><ul><ul><li>From foreign customers to domestic warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From foreign customers to warehouses abroad </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From domestic customers to domestic warehouses </li></ul></ul></ul></ul><ul><ul><li>Transportation mode selection </li></ul></ul><ul><ul><ul><ul><li>Based on a specified service level </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Based on the availability of resources </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Based on shipment priorities </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Based on customer location </li></ul></ul></ul></ul><ul><ul><li>Direct shipment from plant to customers </li></ul></ul><ul><ul><ul><ul><li>In case of Items in shortage </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Incase of Emergency items </li></ul></ul></ul></ul><ul><ul><ul><ul><li>OEM Products </li></ul></ul></ul></ul>Simulation of warehousing and distribution systems
  24. 24. Data requirements (inputs for the simulation model) <ul><ul><li>Number of plants </li></ul></ul><ul><ul><li>Number and location of warehouses </li></ul></ul><ul><ul><li>Number of customers </li></ul></ul><ul><ul><li>Customer demand to warehouses </li></ul></ul><ul><ul><li>Part number produced at different plants </li></ul></ul><ul><ul><li>Bill of materials </li></ul></ul><ul><ul><li>Transportation times </li></ul></ul><ul><ul><ul><ul><li>Between plants and warehouses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Between warehouses and customers </li></ul></ul></ul></ul>Simulation of warehousing and distribution systems
  25. 25. Simulation Outputs and Responses ( Outputs from the Simulation) <ul><ul><li>Average utilization </li></ul></ul><ul><ul><ul><ul><li>Warehouse </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Trucks </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Airplanes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Other resources inside a warehouse </li></ul></ul></ul></ul><ul><ul><li>Inventory Levels </li></ul></ul><ul><ul><ul><ul><li>Production plants </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Warehouses </li></ul></ul></ul></ul><ul><ul><li>Transportation delays </li></ul></ul><ul><ul><ul><ul><li>Between the plant and a warehouse </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Between a warehouse and customers </li></ul></ul></ul></ul><ul><ul><li>Customer orders </li></ul></ul><ul><ul><ul><ul><li>Average waiting times at a warehouse </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Number waiting at a warehouse </li></ul></ul></ul></ul>Simulation of warehousing and distribution systems
  26. 26. 2. Simulation of trucking operations
  27. 27. System Description <ul><ul><li>Freight may be transported directly or via several intermediate terminals </li></ul></ul><ul><ul><li>LTL (less than truckload) or DL (direct load) mode </li></ul></ul><ul><ul><li>Straight truck / Tractor – Trailer combination – in latter case one, two or three trailers are hooked to the tractor by hooking persons (hostlers) at the yard in a terminal </li></ul></ul><ul><ul><li>Truck drivers arrive at the terminal at pre-specified time as per the schedule </li></ul></ul><ul><ul><li>Number of trailers hooked to a tractor may vary depending on the amount of freight </li></ul></ul><ul><ul><li>Set number of loaded trailers are transported by relay, by sleeper, by meet-and-turn drivers, or by rail from each terminal, hub or consolidation center </li></ul></ul><ul><ul><li>Occasionally empty trailers in case of load imbalance – when more freight moves in one direction than in another direction </li></ul></ul>Simulation of trucking operations
  28. 28. <ul><ul><li>Driver pool is divided into following three types: </li></ul></ul><ul><ul><ul><ul><li>Pick-up and delivery drivers : who stay within a city zone </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Relay drivers : who drive trucks from one terminal to the next for a shorter period and return back to the original terminal which is their domicile location </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Sleeper drivers : where two drivers alternate driving and drive to farther destinations with minimum number of stops for a longer period </li></ul></ul></ul></ul><ul><ul><li>When a truck driver is at a terminal location that is not his or her domicile point – he is referred to as foreign driver . At the foreign location the drivers will be provided accommodation to rest for a period of time (say 8 to 10 hours) before driving back to the domicile location – as per the schedule. Foreign drivers have higher priority – so as to reduce the cost of managing them </li></ul></ul><ul><ul><li>Once the drivers return to their domicile location, they go home and wait until their next assignment </li></ul></ul>Simulation of trucking operations
  29. 29. <ul><ul><li>To reduce the cost of managing drivers when they are at foreign terminals, trucking companies set up a pool of meet-and-turn drivers </li></ul></ul><ul><ul><li>These drivers are used to exchange trucks from two terminals moving towards each other when the total transport time is within 8 to 10 hours </li></ul></ul><ul><ul><li>Meet-and-turn drivers at a central point, swap their trucks and turn back to their domicile terminals </li></ul></ul><ul><ul><li>Meet-and-turn drivers start from a domicile terminal and end up at their domicile location </li></ul></ul><ul><ul><li>On arrival straight trucks waits at the yard to wait for its turn to offload </li></ul></ul><ul><ul><li>Tractor- trailer pair – set is unhooked and waits at the yard for offloading, unhooked tractor maybe taken for maintenance checks, refueling etc. </li></ul></ul>Simulation of trucking operations
  30. 30. <ul><ul><li>Each terminal has a dock with sufficient doors for the loaded trailers or trucks to arrive at a pre-specified door and offload </li></ul></ul><ul><ul><li>Off-loading may involve use of manual handling or forklifts or other material handling equipment </li></ul></ul><ul><ul><li>Truck docks are divided into areas specifically for offloading trucks (or trailers) and reloading trucks or trailers </li></ul></ul><ul><ul><li>Some may have same areas for offloading / reloading to take down the time required for the freight to be staged before it is reloaded for transportation to its final destination </li></ul></ul><ul><ul><li>Simulations can be applied to several areas of trucking operations as follows : </li></ul></ul><ul><ul><li>Dock Simulation – modeling and analysis of truck docks </li></ul></ul><ul><ul><li>Terminal Simulation – modeling and analysis of activities taking place inside a terminal </li></ul></ul><ul><ul><li>Line-haul Simulation - combines dock operations and terminal operations network, more complex </li></ul></ul>Simulation of trucking operations
  31. 31. <ul><li>Simulation model is built to address a variety of problems such as : </li></ul><ul><ul><ul><ul><li>Current methods of hooking trailers </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Current procedures used to assign drivers to schedules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Load imbalances within any lane at any terminal </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Equipment needs at any terminal in the lane </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Driver needs at any terminal within the lane </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Management of resources within the lane </li></ul></ul></ul></ul>Simulation of trucking operations
  32. 32. <ul><li>Entities </li></ul><ul><ul><li>Empty trailers at terminals </li></ul></ul><ul><ul><li>Loaded trailers: </li></ul></ul><ul><ul><ul><ul><li>Waiting to be grouped with other trailers </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Waiting to be sent by relay, sleeper, or meet-and-turn mode </li></ul></ul></ul></ul><ul><ul><li>Transport Operators (sleepers, relay and meet-and-turn drivers) </li></ul></ul><ul><ul><li>Tractors </li></ul></ul><ul><ul><li>Trains at the railway station (if rail mode is activated) </li></ul></ul>Simulation of trucking operations
  33. 33. <ul><li>Resources </li></ul><ul><ul><ul><li>Hostlers </li></ul></ul></ul><ul><ul><ul><li>Dispatchers </li></ul></ul></ul><ul><ul><ul><li>Fuelers </li></ul></ul></ul><ul><li>Activities / Processes that require special attention : </li></ul><ul><ul><li>If only sleeper, relay and meet-turn operations are considered, the following activities are performed in a model: </li></ul></ul><ul><ul><ul><ul><li>Off load the loaded trailers after a trip at the dock </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Load the empty trailers at the dock </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Unhook trailers at a terminal </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Prepare (hostler) equipment at a terminal : Get service from hostler to hook / unhook trailers with tractors / Get service at the fueling land or the inspection area </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Drive the truck to the next location via sleeper mode sleeper / relay / meet-and-turn mode </li></ul></ul></ul></ul>Simulation of trucking operations
  34. 34. <ul><ul><li>If the rail mode needs to be modeled, the following activities are performed: </li></ul></ul><ul><ul><ul><ul><li>Movement of trailers to the rail-yard </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Transportation of the trailers from the rail –yard to the terminal </li></ul></ul></ul></ul><ul><ul><ul><ul><li>At the destination terminal, split trailers at the rail-yard and dispatch to the terminal </li></ul></ul></ul></ul>Simulation of trucking operations
  35. 35. <ul><ul><li>Inputs Required for simulation </li></ul></ul><ul><ul><ul><ul><li>Trailer information </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Trailer arrival process information </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Scheduled arrival time distribution </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Trailer information for each schedule : Lane destination, Load destination </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Empty trailer availability information </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Sleeper team arrival process at the origin terminals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Relay ( or meet and turn) driver arrival process at the original terminals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Tractor availability information </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Other pertinent information related to any other dynamic process </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Hostling times </li></ul></ul></ul></ul><ul><ul><ul><ul><li>A set of intermediate locations where sleeper (or relay) trucks stop for unhooking and or hooking or refueling </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Fueling / Inspection times at a terminal </li></ul></ul></ul></ul>Simulation of trucking operations
  36. 36. <ul><ul><li>Fueling / Inspection times at a third party vendor location </li></ul></ul><ul><ul><li>Tractor service times at terminals </li></ul></ul><ul><ul><li>Current number of hostlers per shift at each of the terminals under consideration </li></ul></ul><ul><ul><li>Current number of sleeper, relay and meet-and-turn drivers </li></ul></ul><ul><ul><li>Standard driver roster: </li></ul></ul><ul><ul><ul><ul><li>Arrival times at the terminal </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Number of drivers </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Assigned destination </li></ul></ul></ul></ul><ul><ul><li>Extra driver roster </li></ul></ul><ul><ul><ul><ul><li>Number of drivers </li></ul></ul></ul></ul><ul><ul><li>Driver work rules and DOT regulations associated with sleepers, relay and meet-and-turn drivers </li></ul></ul>Simulation of trucking operations
  37. 37. Outputs from the simulation <ul><ul><li>Utilization of empty trailers at each terminal </li></ul></ul><ul><ul><li>Empty trailer build-up rate and its usage rate over a period of time </li></ul></ul><ul><ul><li>Utilization of drivers at each terminal over a period of time </li></ul></ul><ul><ul><li>Tractor utilization at each terminal and tractor buildup rate and usage rate at a terminal over a period of time </li></ul></ul><ul><ul><li>Number of trailers transported by sleeper teams, relay teams, or meet-and-turn drivers separately at all destination terminals for each day </li></ul></ul><ul><ul><li>Number of trucks on the road over a period of time </li></ul></ul><ul><ul><li>Number of trailers delayed due to unavailability of tractors at the terminals </li></ul></ul><ul><ul><li>Delay times for trailers at each terminal due to unavailability of tractors </li></ul></ul><ul><ul><li>Number of drivers delayed due to the unavailability of schedules at all terminals </li></ul></ul><ul><ul><li>Delay times for the drivers at each terminal due to unavailability of schedules </li></ul></ul><ul><ul><li>Number of tractors delayed due to the unavailability of trailers at each terminal </li></ul></ul><ul><ul><li>Delay times for tractors at each terminal due to unavailability of trailers </li></ul></ul><ul><ul><li>Hostler utilization </li></ul></ul>Simulation of trucking operations
  38. 38. Sample Simulation Outputs Simulation of trucking operations
  39. 39. 3. Simulation of Truck Dock Operations
  40. 40. Objective of Simulation <ul><li>In case of truck dock operation simulations two fundamental objectives are set forth for the simulation study : </li></ul><ul><ul><ul><li>Studying the ways and means of increasing the throughput of a truck dock </li></ul></ul></ul><ul><ul><ul><li>Studying the impact of changes in a facility design before implementing it, to avoid making very costly errors </li></ul></ul></ul><ul><li>Generally following what-if scenarios are analyzed in this simulation: </li></ul><ul><ul><ul><li>To be able to show existing operations, trouble spots and changes in behavior of the existing truck dock as it undergoes changes in terms of new equipment, facility and operations </li></ul></ul></ul><ul><ul><ul><li>To study the impact of changes in processes and policies within each area of the truck dock </li></ul></ul></ul><ul><ul><ul><li>To change the distances traveled and capacity/size/number of forklifts and determine the impact on performance at the truck dock area </li></ul></ul></ul>Simulation of Truck Dock Operations
  41. 41. <ul><li>Entities and Resources </li></ul><ul><ul><li>Yard – where trucks arrive and wait for an empty door </li></ul></ul><ul><ul><li>Doors </li></ul></ul><ul><ul><li>Transporters working at a dock such as forklifts and conveyors </li></ul></ul><ul><ul><li>Staging areas where the freight is temporarily stored prior to sorting and shipping </li></ul></ul><ul><ul><li>Sorting systems </li></ul></ul>Simulation of Truck Dock Operations
  42. 42. Processes <ul><ul><li>Determine door assignments to trucks (based on arrival behavior) at the unloading doors </li></ul></ul><ul><ul><ul><ul><li>Assign trucks to doors starting from left to right </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Assign trucks based on origin or destination terminal to the pre-assigned doors </li></ul></ul></ul></ul><ul><ul><li>Determine door assignments to trucks (based on departure process) at the loading (outbound doors) </li></ul></ul><ul><ul><ul><ul><li>Employ a round- robin method of door assignment, if not waiting at the yard </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Send trucks directly to next- available door, if not waiting at the yard </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Send trucks to doors based on origin or destination terminal </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Send trucks to a common waiting area and to next available door </li></ul></ul></ul></ul><ul><ul><li>Capture door arrival process </li></ul></ul><ul><ul><ul><ul><li>Enter the dock area for offloading </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Consider truck / dock preparation time </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Read the information pertaining to type of truck </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Read the information pertaining to type of contents of the truck </li></ul></ul></ul></ul>Simulation of Truck Dock Operations
  43. 43. <ul><ul><li>Specify doors to forklifts </li></ul></ul><ul><ul><li>Assign, schedule and move and control forklifts for offloading trucks </li></ul></ul><ul><ul><li>Assign , schedule , move and control forklifts for loading trucks </li></ul></ul><ul><ul><li>Pickup and drop-off times for truck forklifts </li></ul></ul><ul><ul><li>Select a sortation conveyor </li></ul></ul>Simulation of Truck Dock Operations
  44. 44. Inputs Data for Truck-dock Simulation <ul><li>Two types of data inputs are required. The first types involves freight types, door information, resources used and equipment specifications as follows: </li></ul><ul><ul><ul><li>Door information ( number of doors, door size ,door locations) </li></ul></ul></ul><ul><ul><ul><li>Freight types (containerized, bulk [sorted/unsorted], loose freight) </li></ul></ul></ul><ul><ul><ul><li>Resources (doors, forklifts, sorting conveyors) </li></ul></ul></ul><ul><ul><ul><li>Operators </li></ul></ul></ul><ul><ul><ul><li>Queue locations </li></ul></ul></ul><ul><ul><ul><li>Forklift specifications (number and types, length and width, loaded/unloaded speed, park locations, work assignment, turning rules, pickup and deposit rules) </li></ul></ul></ul><ul><ul><ul><li>Conveyor specifications (conveyor types, number of segments, input station characteristics, output station characteristics, segment speed, conveyor selection rules, freight movements) </li></ul></ul></ul>Simulation of Truck Dock Operations
  45. 45. <ul><li>Second type of input data involves rigorous data collection at the truck dock as follows: </li></ul><ul><ul><ul><li>Arrival process </li></ul></ul></ul><ul><ul><ul><li>Type of trucks based on freight carried </li></ul></ul></ul><ul><ul><ul><li>Frequency of truck arrivals </li></ul></ul></ul><ul><ul><ul><li>Truck contents (freight type and statistical distribution w/ parameters) </li></ul></ul></ul><ul><ul><ul><li>Truck hostling time distributions </li></ul></ul></ul><ul><ul><ul><li>Door preparation time before offloading </li></ul></ul></ul><ul><ul><ul><li>Door occupancy time by trucks after off-loading </li></ul></ul></ul><ul><ul><ul><li>Loading / Offloading times </li></ul></ul></ul><ul><ul><ul><li>Fork-lift pick up time by freight type </li></ul></ul></ul><ul><ul><ul><li>Fork-lift set down time by freight type at destination points </li></ul></ul></ul>Simulation of Truck Dock Operations
  46. 46. Outputs from simulation <ul><ul><li>Measure the impact of eliminating certain truck types at inbound dock </li></ul></ul><ul><ul><li>Measure the Impact of additional doors </li></ul></ul><ul><ul><li>Measure the Impact of fork-lift assignment policies to doors </li></ul></ul><ul><ul><li>Determine optimum Number of doors required and forklift assignment policies </li></ul></ul><ul><ul><li>Time window to complete off-loading, staging and reloading all the trucks </li></ul></ul><ul><ul><li>Amount of work load expected at all areas that may receive freight during a time period </li></ul></ul>Simulation of Truck Dock Operations
  47. 47. Sample Outputs Simulation of Truck Dock Operations
  48. 48. 4. Simulation of ramp operations in air cargo hubs Purpose of simulation model: <ul><ul><li>To develop a simulation model that has the ability to show ramp operations crew the problems, trouble spots, and changes in behavior of the existing ramp operations as the air-cargo hub undergoes changes </li></ul></ul><ul><ul><li>To study the impact of changes in operations and policies within each area of the ramp </li></ul></ul><ul><ul><li>To perform a comparative analysis, current versus new layout of aircraft parking, current versus new communication procedures, current new tug and dolly assignment rules and so on. </li></ul></ul><ul><ul><li>To study the impact of additional aircrafts and gates on the ramp and determine the number of K- loaders and tug and dollies </li></ul></ul><ul><ul><li>To study the impact of changing the number of dollies per tug and number of tugs per plane on the average time required to offload a plane. Study the impact of these operation parameters on the varying number of planes that arrive at the hub during a night </li></ul></ul>
  49. 49. Entities, Resources and Activities <ul><ul><li>Number of planes </li></ul></ul><ul><ul><li>Flight profile </li></ul></ul><ul><ul><li>Plane arrival time distributions </li></ul></ul><ul><ul><li>Total number of tugs </li></ul></ul><ul><ul><li>Number of tugs per plane </li></ul></ul><ul><ul><li>Number of dollies per tug </li></ul></ul><ul><ul><li>Number of K- loaders </li></ul></ul>Simulation of ramp operations in air cargo hubs
  50. 50. Inputs for simulation model <ul><ul><li>Number of gates </li></ul></ul><ul><ul><li>Ramp maps </li></ul></ul><ul><ul><li>Technical specifications of sort-line conveyors,tugs, dollies and forklifts </li></ul></ul><ul><ul><li>Plane types </li></ul></ul><ul><ul><li>Flight information </li></ul></ul><ul><ul><li>Tail sheet and arrival/ departure information </li></ul></ul><ul><ul><li>Number of container positions that each plane type can carry </li></ul></ul><ul><ul><li>Number of bellies </li></ul></ul><ul><ul><li>Number of containers each belly fills up by plane type </li></ul></ul><ul><ul><li>Number of dollies per tug </li></ul></ul><ul><ul><li>Team make-up for offloading and reloading container from/to a plane </li></ul></ul><ul><ul><li>Number of tugs/ dollies/ forklifts </li></ul></ul><ul><ul><li>Conveyor location and characteristics </li></ul></ul><ul><ul><li>Plane parking location rules </li></ul></ul><ul><ul><li>Runway behavior </li></ul></ul>Simulation of ramp operations in air cargo hubs
  51. 51. What – if Scenarios <ul><ul><li>Changes in number of tugs per plane </li></ul></ul><ul><ul><li>Changes in number of dollies hooked to each tug </li></ul></ul><ul><ul><li>Changes in total number of tugs used on the ramp </li></ul></ul><ul><ul><li>Changes in aircraft arrival process / departure process </li></ul></ul><ul><ul><li>Changes in number of K loaders </li></ul></ul><ul><ul><li>Changes in number of transfer forklifts </li></ul></ul><ul><ul><li>Changes in work rules </li></ul></ul><ul><ul><li>Impact of changes in the tug assignment to the aircraft </li></ul></ul>Simulation of ramp operations in air cargo hubs
  52. 52. Outputs for the simulation model <ul><ul><li>Total number of containers offloaded during an hour, total number of planes offloaded during an hour, average time to offload a plane, and completion time for offloading all the planes that arrived during night/ day </li></ul></ul><ul><ul><li>Offloading / Reloading times for 10 planes,20 planes, 30 planes and so on. </li></ul></ul><ul><ul><li>Determine number of gates for all arriving planes as created by the simulation model </li></ul></ul><ul><ul><li>Actual time at which the aircraft is fully offloaded or loaded </li></ul></ul><ul><ul><li>Offloading time for each aircraft that arrived during the night/day </li></ul></ul>Simulation of ramp operations in air cargo hubs
  53. 53. THANK YOU