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Profit optimization for multi-mode repetitive construction project with cash flows using metaheuristics

Sroka Bartłomiej, Rosłon Jerzy, Podolski Michał, Bożejko Wojciech, Burduk Anna, Wodecki Mieczysław

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

441--457

EN

The article presents the profit optimization model for multi-unit construction projects. Such projects constitute a special case of repetitive projects and are common in residential, commercial, and industrial construction projects. Due to the specific character of construction works, schedules of such projects should take into account many different aspects, including durations and costs of construction works, the possibility of selecting alternative execution modes, and specific restrictions (e.g., deadlines for the completion of units imposed by the investor). To solve the NP-hard problem of choosing the order of units’ construction and the best variants of works, the authors used metaheuristic algorithms (simulated annealing and genetic search). The objective function in the presented optimization model was the total profit of the contractor determined on the basis of the mathematical programming model. This model takes into account monthly cash flows subject to direct and indirect costs, penalties for missing deadlines, costs of work group discontinuities, and borrowing losses. The presented problem is very important for maintaining a good financial condition of the enterprise carrying out construction projects. In the article, an experimental analysis of the proposed method of solving the optimization task was carried out in a model that showed high efficiency in obtaining suboptimal solutions. In addition, the operation of the proposed model has been presented on a calculation example. The results obtained in it are fully satisfying.

2

Optimization of production process for resource utilization

Bozejko Wojciech, Burduk Anna, Pempera Jaroslaw, Wodecki Mieczysław

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1251--1258

EN

The paper presents a method of scheduling execution of technological operations in work centres in a company manufacturing seats for passenger cars. To that end, an optimization algorithm based on the B&B method was developed, aimed at minimizing the number of employees necessary for operation of the work centres and at maximizing capacity of the manufacturing process. Efficiency and effectiveness of the algorithm was verified on the grounds of real data coming from the manufacturing company.

3

Flowshop scheduling of construction processes with uncertain parameters

Bozejko Wojciech, Hejducki Zdzisław, Wodecki Mieczysław

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

194--204

EN

In the paper a construction scheduling problem – namely flowshop – with minimizing the sum of penalties for exceeding the deadline of building structures completion is considered. The problem is illustrated by the investment task concerning the implementation of twelve apartment buildings forming a part of a new housing estate. Uncertain parameters of the system are represented either by fuzzy numbers or random variables, whereas random variables have normal or the Erlang distribution. Since even the deterministic version of the problem is strongly NP-hard, the approximate algorithm based on the tabu search method was used to its solution. The performed computational experiments showed large solution resistance against any potential interference of parameters of the problem.