Abstract. The article presents the resource-constrained project scheduling problem with the maximisation of discounted cash flows from the contractor's perspective: with cash outflows related to starting individual activities and with cash inflows for completing project stages (milestones). The authors propose algorithms for improving a forward active schedule by iterative one-unit right shifts of activities, taking into account different resource flow networks. To illustrate the algorithms and problem, a numerical example is presented. Finally, the algorithms are tested using standard test problems with additionally defined cash flows and contractual milestones.

The main objective of this article is to describe Industry 4.0 and key manufacturing-technology-related technological and business challenges for manufacturing companies. The groups especially interested in the industry 4.0 implementation are operations, technical and production directors responsible for operational excellence of manufacturing plants, strategic development and business continuity. Based on latest Industry 4.0 and manufacturing technology market research, factories located in Poland are less technologically advanced than its counterparts in West European plants. Accordingly, development of the model for assessing the current level of maturity for manufacturing technology related to Industry 4.0 initiative becomes a relevant research task. In the article, key Industry 4.0 related technological areas will be described. Based on the extensive research into international references and industrial consulting experiences in industrial business consulting conducted in Polish manufacturing companies, the manufacturing technology ManuTech Maturity Model (MTMM) concept related to Industry 4.0 will be developed and presented. A substantial and innovative part of the article will be devoted to the adjustment of proposed maturity model to specific features of the Polish industrial and manufacturing sector. This will be relevant due to noticeable differences in the level of technological advancement between Western and Eastern Europe sectors.

Abstract. The paper presents the resource-constrained project scheduling with cash flow optimisation. New project models with bonuspenalty system and payoff in stages have been proposed. For the models presented, the application of proactive scheduling is analysed, as designed to improve project execution under uncertainty. Next, schedule robustness is discussed and measures of robustness are proposed.

Abstract. The paper presents a formal description of the resource allocation problem for resource-constrained project scheduling. A schedule can be executed by various resource flow networks which may differ in terms of resistance to disruptions occurring during project execution. The authors define such criteria of evaluating a resource flow network which can be more useful than robustness metrics used so far in the research. The authors discuss the importance of robust scheduling for execution projects and propose metrics for resource allocation robustness which take into consideration the stability of the final schedule. Those metrics make it possible to carry out a more precise analysis concerning the properties of the resource flow network in terms of its robustness to disruptions in comparison with a well known flexibility indicator, flex.

Abstract. The paper analyses the problem of discounted cash flow maximising for the resource-constrained project scheduling from the project contractor's perspective. Financial optimisation for the multi-stage project is considered. Cash outflows are the contactor's expenses related to activity execution. Cash inflows are the client's payments for the completed milestones. To solve the problem, the procedure of backward scheduling taking into account contractual milestones is proposed. The effectiveness of this procedure, as used to generate solutions for the simulated annealing algorithm, is verified with use of standard test instances with additionally defined cash flows and contractual milestones.

Abstract. This paper presents a Resource-Constrained Project Scheduling Problem (RCPSP) settled by contractual milestones. The criterion analysed here is the maximisation of aggregate discounted cash flows from the contractor's perspective, known as an RCPSP problem with Discounted Cash Flows (RCPSPDCF). The cash flows analysed here cover the contractor's cash outflows (negative cash flows), related to the commencement of individual activities, and cash inflows (positive cash flows) after the fulfilment of individual milestones. The authors propose a two-phase algorithm for solving the problem defined. In the first phase, the simulated annealing metaheuristics is used, designed to identify a forward schedule with as high total DCF as possible. In the second phase, the best first-phase schedule is improved by right shifts of activities. To this end, the procedure which iteratively shifts tasks by one unit is applied, with a view to maximising the objective function. Activity shifts take into consideration precedence and resource constraints, and they are performed for a specified resource allocation to activities. This paper also includes an analysis of the problem for a sample project. The results of computational experiments are then analysed. The experiments were run with the use of standard test problems from the Project Scheduling Problem LIBrary (PSPLIB), with additionally defined cash flows and contractual milestones.

Abstract. This article presents a new simulated annealing algorithm that provides very high quality solutions to the vehicle routing problem. The aim of described algorithm is to solve the vehicle routing problem with time windows. The tests were carried out with use of some well known instances of the problem defined by M. Solomon. The empirical evidence indicates that simulated annealing can be successfully applied to bi-criterion optimization problems.

Abstract. The paper discusses the problem of robust buffer allocation for ResourceConstrained Project Scheduling Problem (RCPSP) with predefined milestones 1 , for which execution deadlines have been established. To solve the problem, an algorithm is proposed supporting insertion of unit time buffers, with the simultaneous maximisation of new metrics of arrangement robustness. The presented results of experimental research speak for usability of the solutions proposed. The effectiveness is studied with use of test tasks 2 included in the Project Scheduling Problem Library (PSPLIB) with additionally specified project milestones.