Solve Production Allocation and Reconciliation Problems using the same NetworkAlkis Vazacopoulos
Production allocation is a business accounting practice used throughout the processing world to proportionately and quantitatively assign measurement error and production expenditures or overheads to internal and external business owners. Reconciliation is a scientific function to vet production data of gross errors or non-random variation if it occurs and to find more precise estimates of the measured values. The consequence of our proposed technique is to allow these two functions the capability to use the same production network or flow-path. Only one model is required to be maintained eliminating the possibility that potentially costly mis-allocation will occur due to business and engineering model-mismatch. Mis-allocation due to measurement errors can still be problematic as we illustrate in an example, but should be reduced over time because of the reconciliation measurement diagnostics.
The document discusses various process and thread scheduling methods. It covers the organization of schedulers, common scheduling algorithms like priority scheduling, and comparisons of scheduling methods. It also describes the priority inversion problem and solution of dynamic priority inheritance to prevent lower priority processes from indefinitely blocking higher priority processes.
Stock Decomposition Heuristic for Scheduling: A Priority Dispatch Rule ApproachAlkis Vazacopoulos
Highlighted in this article is a closed-shop scheduling heuristic which makes use of the traditional priority dispatch rule approach found in open-shop scheduling such as job-shop scheduling. Instead of prioritizing and scheduling one job or project (or stock-order) at a time, we schedule one stock or stock-group at a time where a stock-group is a collection of individual stocks and their one or more stock-orders. These stocks can be feed-stocks, intermediate-stocks or product-stocks of which we focus on product-stocks given that most production is demand-driven. A key feature of this heuristic is our ability to compress the production network or superstructure so that only those unit-operations necessary to produce the stocks in question are included in the model thus reducing the size of the problem considerably at each iteration of the heuristic. The stock-specific network compression technique uses what we call a unit-capacity transshipment linear program to successively determine which unit-operations are redundant when making a particular stock. This heuristic is also particularly useful for those process industries that can potentially produce many product-stocks but only a fraction of these are produced within the scheduling horizon whereby the model is significantly reduced at solve time to include only those stocks that are demanded whereby redundant unit-operations are removed. An illustrative example is provided with recycle loops (i.e., stock flow-reversals) and shared units or equipment (i.e., unit flow-reversals) that demonstrates the effectiveness and efficiency of the technique.
Scheduling Fixed Priority Tasks with Preemption ThresholdDeepak Raj
This document summarizes a seminar presentation on scheduling fixed-priority tasks with preemption thresholds. The presentation covered scheduling basics, real-time scheduling goals, classification of scheduling algorithms, motivation for using fixed-priority scheduling with preemption thresholds (FPTS), preemptive vs. non-preemptive scheduling, the concept of limited preemptive scheduling with preemption thresholds, an example to motivate FPTS, schedulability analysis including worst-case response time calculation, critical instant, level-1 active period, algorithms to find optimal preemption thresholds and optimal priorities/thresholds.
Smarter Scheduling (Priorities, Preemptive Priority Scheduling, Lottery and S...David Evans
University of Virginia
cs4414: Operating Systems
http://rust-class.org
Scheduling Recap
Real-Time Scheduling
On-Demand vs. Planned Scheduling
First Come, First Served
Round-Robin
Priorities
Priority Preemptive
Priority Inversion
Lottery Scheduling
Stride Scheduling
For embedded notes, see: http://rust-class.org/class-11-smarter-scheduling.html
Solve Production Allocation and Reconciliation Problems using the same NetworkAlkis Vazacopoulos
Production allocation is a business accounting practice used throughout the processing world to proportionately and quantitatively assign measurement error and production expenditures or overheads to internal and external business owners. Reconciliation is a scientific function to vet production data of gross errors or non-random variation if it occurs and to find more precise estimates of the measured values. The consequence of our proposed technique is to allow these two functions the capability to use the same production network or flow-path. Only one model is required to be maintained eliminating the possibility that potentially costly mis-allocation will occur due to business and engineering model-mismatch. Mis-allocation due to measurement errors can still be problematic as we illustrate in an example, but should be reduced over time because of the reconciliation measurement diagnostics.
The document discusses various process and thread scheduling methods. It covers the organization of schedulers, common scheduling algorithms like priority scheduling, and comparisons of scheduling methods. It also describes the priority inversion problem and solution of dynamic priority inheritance to prevent lower priority processes from indefinitely blocking higher priority processes.
Stock Decomposition Heuristic for Scheduling: A Priority Dispatch Rule ApproachAlkis Vazacopoulos
Highlighted in this article is a closed-shop scheduling heuristic which makes use of the traditional priority dispatch rule approach found in open-shop scheduling such as job-shop scheduling. Instead of prioritizing and scheduling one job or project (or stock-order) at a time, we schedule one stock or stock-group at a time where a stock-group is a collection of individual stocks and their one or more stock-orders. These stocks can be feed-stocks, intermediate-stocks or product-stocks of which we focus on product-stocks given that most production is demand-driven. A key feature of this heuristic is our ability to compress the production network or superstructure so that only those unit-operations necessary to produce the stocks in question are included in the model thus reducing the size of the problem considerably at each iteration of the heuristic. The stock-specific network compression technique uses what we call a unit-capacity transshipment linear program to successively determine which unit-operations are redundant when making a particular stock. This heuristic is also particularly useful for those process industries that can potentially produce many product-stocks but only a fraction of these are produced within the scheduling horizon whereby the model is significantly reduced at solve time to include only those stocks that are demanded whereby redundant unit-operations are removed. An illustrative example is provided with recycle loops (i.e., stock flow-reversals) and shared units or equipment (i.e., unit flow-reversals) that demonstrates the effectiveness and efficiency of the technique.
Scheduling Fixed Priority Tasks with Preemption ThresholdDeepak Raj
This document summarizes a seminar presentation on scheduling fixed-priority tasks with preemption thresholds. The presentation covered scheduling basics, real-time scheduling goals, classification of scheduling algorithms, motivation for using fixed-priority scheduling with preemption thresholds (FPTS), preemptive vs. non-preemptive scheduling, the concept of limited preemptive scheduling with preemption thresholds, an example to motivate FPTS, schedulability analysis including worst-case response time calculation, critical instant, level-1 active period, algorithms to find optimal preemption thresholds and optimal priorities/thresholds.
Smarter Scheduling (Priorities, Preemptive Priority Scheduling, Lottery and S...David Evans
University of Virginia
cs4414: Operating Systems
http://rust-class.org
Scheduling Recap
Real-Time Scheduling
On-Demand vs. Planned Scheduling
First Come, First Served
Round-Robin
Priorities
Priority Preemptive
Priority Inversion
Lottery Scheduling
Stride Scheduling
For embedded notes, see: http://rust-class.org/class-11-smarter-scheduling.html
