Resource constrained scheduler

Lim, M. and Karimi, I.A. (2003) Resource-constrained scheduling of parallel production lines using asynchronous slots. Ind. Eng. Chem. Res., 42, 6832-6842. 

Resource-constrained scheduling (RTS) Hnd a feasible (or optimal) schedule for X that obeys the precedence ccxistraints and meets the resource constraints for each functional unit type. 

Two types of scheduling may be performed at this stage. A time-constrained scheduler finds one of the cheapest schedules under the constraint of the maximum number of control steps While a resource-constrained scheduler finds one of the fastest schedules based on a resource constraint. 

Resource-constrained Scheduling Given constraints on the resources, find one of the fastest schedules. 

The time-constrained scheduling finds its application in real time digital signal processing where the sampling rate dictates how fast a data must be processed. We restrict the input to the time-constrained scheduler be single basic blocks or iterative loops. The resource-constrained scheduler, on the other hand, is applicable to more general applications and accepts inputs that contain multiple loops and/or branches. 

Our resource-constrained scheduler for a basic block consists of four substeps ... 

For the resource-constrained scheduling, we have proposed an optimum ILP formulation. We apply the list scheduling, the ASAP scheduling and the ALAP scheduling to greatly reduce the solution space. We have also extended the formulation to schedule multicycle operations as well as to take constraints on both the number of buses and the number of registers. 

Herroelen, W. and Demeulemeester, E. (1998) Resource-constrained project scheduling a survey of recent developments. Comput Ops Res, 25, 279-302. 

Mendez, C.A., Henning, G.P. and Cerd , J. (2001) An MILP continuoustime approach to short-term scheduling of resource-constrained multistage flow-shop batch facilities. Comput. Chem. 

Each work package in the WBS is decomposed into the activities required to complete its predefined scope. A list of activities is constructed and the time to complete each activity is estimated. Estimates can be deterministic (point estimates) or stochastic (distributions). Precedence relations among activities are defined, and a model such as a Gantt chart, activity on arc (AOA), or activity on nodes (AON) network is constructed (Shtub et al. 1994). An initial schedule is developed based on the model. This unconstrained schedule is a basis for estimating required resources and cash. Based on the constraint imposed by due dates, cash and resource avaUabUity, and resource requirements of other projects, a constrained schedule is developed. Further tuning of the schedule may be possible by changing the resource combination assigned to activities (these resource combinations are known as modes). 

Merkle, D., Middendorf, M., Schmeck, H. Ant colony optimization for resource-constrained project scheduling. IEEE Trans. Evol. Comput. 6, 893-900 (2000) Mohamad, M.M. Articulated robots motion planning using foraging ant strategy. J. 

Le Pape C. 1998. Implementation of resource constraints in ILOG SCHEDULE A library for the development of constrained-based scheduling systems, Intell. Syst. Eng., 3(2), 55-66. 

The goal of advanced planning is the synchronization of constrained material and resources to independent demand. Its purpose is to create a plan that is feasible with respect to aU resources required (machines, material, tooling etc.) with sufficient operational slack to permit resequencing of work orders to enhance production efficiency. The independent demand comes from several sources, including customer orders, demand forecasts, master production schedules, transfer orders (i.e., orders from other plants), and the company s policies on safety stock. The advanced planner also considers the work order schedule already released to the shop floor as presented by the advanced scheduler. For each end-item demand, a complete requirements explosion is done using that item s BOM and... 

Clearly, this class of problems requires a triple optimisation, so-called integrated optimisation, at the same time allocating available resources to each production line, production line sequencing and production line scheduling. It is a multidimensional, precedence-constrained, knapsack problem. The knapsack problem is a classical NP-hard problem, and it has been thoroughly studied in the last few decades [2]. 

We have described an approach for processor synthesis. We divide the problem into three interdependent subtasks, namely, operation scheduling, data path binding and controller synthesis. The first subtask includes both time-constrained and resource-... 

Schedules are constrained by projected manpower and budget resource availability along with duration of outages, as defined by interaction of the RSIP organization and DOE. This ensures that the higher priority items are accomplished within realistic budgetary constraints. RSIP procedures were revised in June 1990 to reflect how this information is used in the budget process. 

---