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1

The pert method in estimating project duration

Nafkha R.

Information Systems in Management

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2016

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Vol. 5, No. 4

542--550

EN

In order to complete a project in time, companies must determine both the duration of the entire project as well as each of its individual tasks. Very often less experienced companies do not collect data affecting time limit for project completion. Then time required to perform specified activities are determined based on estimation and companies own experience. To minimize the risk error arising as a result of using incomplete historical data and simultaneously increasing the effectiveness of estimating the duration of the project, most project managers with pleasure use the PERT method (Program Evaluation and Review Technique) to estimate the duration of individual tasks of the project on the basis of three intermediate estimation values: optimistic, realistic and pessimistic. This paper will set the duration of an IT (Information Technology) project implementation tasks, determine both critical tasks as well as critical path of the project. Based on estimates deadlines events values, the probability of occurrence time limits shall be also appointed.

2

Discrete-continuous project scheduling with preemptable activities

Różycki R., Waligóra G., Węglarz J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 2

383--393

EN

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.

3

Assessment of task duration in investment projects

Relich M.

Management

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2010

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Vol. 14, no 2

136-147

EN

The paper aims to present possibilities of estimation improvement of task time in projects through the use of different techniques. In this paper a case is considered, where the task time, determined from similar past project, is distinguished by a significant variation. In this case, the traditional statistical methods do not determine the satisfying estimates of task time. To supplement the techniques, the application of neural network and fuzzy neural network is proposed. The use of more complicated techniques is dedicated for the critical tasks that are located on the critical path and require the essential resources of the organisation.

PL

Celem niniejszej pracy było przedstawienie możliwości poprawy szacowania czasu realizacji czynności w projektach poprzez wykorzystanie różnych technik. W pracy przyjęto założenie, że czas czynności realizowanych w przeszłych podobnych projektach charakteryzuje się istotną zmiennością. W tym przypadku klasyczne metody statystyczne nie wyznaczają satysfakcjonujących ocen czasu realizacji czynności. W celu poprawy oszacowań proponuje się wykorzystanie sieci neuronowych oraz rozmyto-neuronowych. Wykorzystanie bardziej skomplikowanych technik jest szczególnie wskazane w przypadku czynności krytycznych, to znaczy czynności znajdujących się na ścieżce krytycznej oraz angażujących znaczne zasoby przedsiębiorstwa.