Comparative Analysis of Some Metaheuristics for Discrete-Continuous Project Scheduling with Activities of Identical Processing Rates

2016 ◽  
Vol 33 (03) ◽  
pp. 1650015 ◽  
Author(s):  
Grzegorz Waligóra
Keyword(s):  
Comparative Analysis ◽  
Project Scheduling ◽  
Net Present Value ◽  
Renewable Resource ◽  
Concave Function ◽  
Cash Flows ◽  
Future Research ◽  
Scheduling Problems ◽  
Time Intervals ◽  
Lump Sum

Discrete-continuous project scheduling problems with positive discounted cash flows and maximization of the net present value are considered. A class of these problems with an arbitrary number of discrete resources and one continuous, renewable resource is taken into account. Activities are nonpreemptable, and the processing rate of each activity is the same continuous, increasing, and concave function of the amount of the continuous resource allotted to the activity at a time. Three common payment models — lump sum payment, payments at activity completion times, and payments in equal time intervals are analyzed. Adaptations of three well-known metaheuristics — simulated annealing, tabu search, and genetic algorithm are described. The paper focuses on a comparative analysis of the metaheuristics. The algorithms are computationally compared on a basis of an extensive experiment. Some conclusions and directions for future research are pointed out.

scholarly journals Optimal Replenishment for Perishable Products with Inventory-Dependent Demand and Backlogging under Continuous and Discrete Progressive Payments

2018 ◽  
Vol 10 (10) ◽  
pp. 3723 ◽  
Author(s):  
Longfei He ◽  
Han Gao ◽  
Xiao Zhang ◽  
Qinpeng Wang ◽  
Chenglin Hu
Keyword(s):  
Trade Credit ◽  
Cash Flows ◽  
Future Research ◽  
Time Intervals ◽  
Ordering Policy ◽  
Replenishment Policy ◽  
Convexity Assumptions ◽  
Short Time ◽  
The Impact ◽  
Dependent Demand

Managing material and cash flows attracts concerns of physical and financial departments in most companies. We, therefore, focus on optimizing the replenishment policy for a channel with stock-dependent demand considering item deterioration and order backlogging under two financial schemes of progressive trade credit periods. We take both the continuous payment regime (CPR) and discrete payment regime (DPR) into account in the progressive trading process, which generates ten distinct scenarios. We show that the profit functions may not necessarily be concave and accordingly give a corresponding computing algorithm, which relaxes the convexity assumptions of objective functions in the existing literature and consequently enrich the research. We address the formulation characterization and the logic of pursuing global optimization from models arising in all settings. Computational studies and simulations are conducted to illustrate the effect of various parameters on the optimal replenishing policy and profit. Numerical experiments show that the CPR scheme is dominantly prior to DPR for long replenishment time intervals, whereas it is exactly the opposite for short time intervals. We also examine the impact of the shortage cost and deteriorating rate on optimum ordering policy and channel performance. Finally, future research directions are addressed in the end.

scholarly journals Discrete-continuous project scheduling with preemptable activities

2016 ◽  
Vol 64 (2) ◽  
pp. 383-393 ◽  
Author(s):  
R. Różycki ◽  
G. Waligóra ◽  
J. Węglarz
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Future Research ◽  
Scheduling Problems ◽  
Feasible Schedule ◽  
Project Duration ◽  
Processing Rate ◽  
Rate Functions ◽  
Continuous Resources ◽  
Increasing Function

Abstract In this paper, discrete-continuous project scheduling problems with preemptable activities are considered. In these problems, activities of a project simultaneously require discrete and continuous resources for their execution. The activities are preemptable, and the processing rate of each activity is a continuous, increasing function of the amount of a single continuous resource allotted to the activity at a time. The problem is to find a precedence- and discrete resource-feasible schedule and, simultaneously, continuous resource allocation that would minimize the project duration. Convex and concave processing rate functions are considered separately. We show that for convex functions the problem is simple, whereas for concave functions a special methodology has to be developed. We discuss the methodology for three cases of the problem: no discrete resource constraints, one discrete resource being a set of parallel, identical machines, and an arbitrary number of discrete resources. In each case we analyze separately independent and precedence-related activities. Some conclusions and directions for future research are given.

scholarly journals Influence of the contractor’s payment method on the economic effectiveness of the construction project from the contractor’s point of view

2018 ◽  
Vol 8 (1) ◽  
pp. 562-570
Author(s):  
Jacek Zawistowski ◽  
Janusz Kulejewski
Keyword(s):  
Cash Flow ◽  
Net Present Value ◽  
Construction Project ◽  
Cash Flows ◽  
Optimization Techniques ◽  
Point Of View ◽  
Economic Effectiveness ◽  
Unit Price ◽  
Payment Method ◽  
Lump Sum

Abstract The scope of the paper is the problem of the economic effectiveness of the construction project from the contractor’s point of view. The two main construction contract types are taken under consideration: the unit price contract based on the bill of quantities and the lump sum contract. The net present value (NPV) is adopted in this paper as the basic economic efficiency criterion of the construction project. The NPV of the project for the contractor is calculated here as the sum of all future monthly contractor’s cash flows (both incoming and outgoing) discounted by using the monthly cost of contractor’s capital invested into the project. For the cash flow calculations, two basic payment methods are considered, depending on the type of the contract: the monthly payments in the case of the unit price contract and the payments for the WBS (Work Breakdown Structure) billing elements in the case of the lump sum contract. The contractor’s monthly cash flow analysis also makes it possible to determine the monthly cash requirements for the contractor to finance the works each month and the total cash requirement to finance the project as the whole. This allows the contractor to correctly plan the financing of the project depending on the type of contract and the payment method. Moreover, using the optimization techniques known in the scheduling theory, for example based on the priority rules as in the case of the RCSP, one may try to improve the economic effectiveness of the project or to lower the cash requirement for the project.However, as shown by the authors, it does not have bring the expected results in the case of the lump sum contract.

scholarly journals A Priority Rule-Based Heuristic for Resource Investment Project Scheduling Problem with Discounted Cash Flows and Tardiness Penalties

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Amir Abbas Najafi ◽  
Fatemeh Azimi
Keyword(s):  
Project Scheduling ◽  
Net Present Value ◽  
Heuristic Method ◽  
Investment Project ◽  
Cash Flows ◽  
Scheduling Problem ◽  
Solution Approach ◽  
Resource Investment ◽  
Project Scheduling Problem ◽  
Resource Investment Problem

Resource investment problem with discounted cash flows (RIPDCFs) is a class of project scheduling problem. In RIPDCF, the availability levels of the resources are considered decision variables, and the goal is to find a schedule such that the net present value of the project cash flows optimizes. In this paper, we consider a new RIPDCF in which tardiness of project is permitted with defined penalty. We mathematically formulated the problem and developed a heuristic method to solve it. The results of the performance analysis of the proposed method show an effective solution approach to the problem.

Application of Three Meta-Heuristic Algorithms for Maximizing the Net Present Value of a Resource-Constrained Project Scheduling Problem with Respect to Delay Penalties

2016 ◽  
Vol 3 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Masoud Rabbani ◽  
Azadeh Arjmand ◽  
Mohammad Mahdi Saffar ◽  
Moeen Sammak Jalali
Keyword(s):  
Project Scheduling ◽  
Large Scale ◽  
Net Present Value ◽  
Heuristic Algorithms ◽  
Optimal Solution ◽  
Cash Flows ◽  
Scheduling Problem ◽  
Resource Constrained ◽  
Resource Constrained Project Scheduling ◽  
Project Scheduling Problem

The Resource Constrained Project Scheduling Problem (RCPSP) is been studied under different kinds of constraints and limitations. In this paper, we are going to consider the discounted cash flows for project activities, and delay penalties which occur when the project make span exceeds its deadline as the objective function of the RCPSP. To solve the model, we will take advantage of three different meta-heuristic algorithms - Genetic Algorithm (GA), Imperialist Competitive Algorithm (ICA), and Shuffled Frog Leaping Algorithm (SFLA) - to achieve the optimal solution of the problem. The evaluation of the algorithms performance reveals that, in comparison with ICA and SFLA, GA performs better, especially in large-scale problems.

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