Modeling and Solving Project Portfolio and Contractor Selection Problem Based on Project Scheduling under Uncertainty

AbstractIn this paper a new formulation of the project portfolio selection problem based on the project schedules in uncertain circumstances have been proposed. The project portfolio selection models usually disregard the project scheduling, whereas is an element of the project selection process. We investigate a project portfolio selection problem based on the schedule of the projects, so that the minimum expected profit would be met in the shortest possible time period. Also due to uncertain nature of durations of the activities, this duration considered as the semi-trapezoidal fuzzy numbers. Finally, a fuzzy linear programming model is developed for the problem, where the results indicated the validity of the presented model

Proposing a new methodology for prioritising the investment strategies in the private sector of Iran

This article proposes a systematic and organised approach for group decision-making in the presence of the uncertainty involved in expert judgments as used in multi-criteria decision-making (MCDM) issues. This procedure comprises the selection of the optimum alternative with respect to the evaluation criteria under consideration, in particular to select the strategy of investing. However, the selection of the investment strategy is difficult on account of considering the numerous quantitative and qualitative parameters like benefits, opportunities, costs, and risks. However, it is possible that these parameters have a significant influence on each other. A decision-making trial and evaluation laboratory (DEMATEL), used to define the influential network of elements, can be employed to construct a network relationship map (NRM). On the other hand, according to whether the information is incomplete or unavailable, uncertainty is an inseparable part of making decision for solving the MCDM problems. Therefore, this article proposes a new hybrid model based on analytic hierarchical process (AHP), DEMATEL, and echnique for Order of Preference by Similarity to Ideal Solution (TOPSIS) techniques under fuzzy environment to evaluate the problem of the selection of the investment strategy. To achieve the aim, a three-step process is presented to solve a sophisticated problem. First, the AHP method is employed to break down the investment problem into simple structure and calculate the importance weights of criteria by using a pairwise comparison process. Second, the DEMATEL technique is applied for considering interdependence and dependencies and computing the global weights of benefit, opportunities, cost, and risk (BOCR) factors. Finally, the fuzzy TOPSIS methodology is used for prioritising the possible alternatives. To demonstrate the potential application of the proposed model, a numerical example is illustrated and investigated. The results show that the proposed model has a high ability to prioritise the strategies of investing

Proposing a neural network model to predict time and cost claims in construction projects

Despite broad improvements in construction management, claims still are an inseparable part of many con-struction projects. Due to huge cases of claim in construction industry, this study argues that claim management is a significant factor in construction projects success. In this study, the most possible causes of these emerging claims are identified and statistically ranked by Probability-Impact Matrix. Subsequently, by classifying claims in different cases, the most important ones are ranked in order to achieve a better understanding of claim management in each project. In this regard, a new index is defined, being able to be applied in a variety of projects with different time and cost values, to calculate the amount of possible claims in each project along with related ratios with respect to the cost and time of each claim. This study introduces a new model to predict the frequency of claims in construction projects. By using the proposed model, the rate of possible claims in each project can be obtained. This model is validated by applying it into fitting case studies in Iran construction industry

Handling equipment Selection in open pit mines by using an integrated model based on group decision making

Process of handling equipment selection is one of the most important and basic parts in the project planning, particularly mining projects due to holding a high charge of the total project's cost. Different criteria impact on the handling equipment selection, while these criteria often are in conflicting with each other. Therefore, the process of handling equipment selection is a complex and multi criteria decision making problem. There are a variety of methods for selecting the most appropriate equipment among a set of alternatives. Likewise, according to the sophisticated structure of the problem, imprecise data, less of information, and inherent uncertainty, the usage of the fuzzy sets can be useful. In this study a new integrated model based on fuzzy analytic hierarchy process (FAHP) and fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) is proposed, which uses group decision making to reduce individual errors. In order to calculate the weights of the evaluation criteria, FAHP is utilized in the process of handling equipment selection, and then these weights are inserted to the FTOPSIS computations to select the most appropriate handling system among a pool of alternatives. The results of this study demonstrate the potential application and effectiveness of the proposed model, which can be applied to different types of sophisticated problems in real problems

Computing latest starting times of activities in interval-valued networks with minimal time lags

This paper deals with problems of determining possible values of earliest and latest starting times of an activity in networks with minimal time lags and imprecise durations that are represented by means of interval or fuzzy numbers. Although minimal time lags are practical in different projects, former researchers have not considered these problems. After proposing propositions which reduce the search space, a novel polynomial algorithm is presented to compute intervals of possible values of latest starting times in interval-valued networks with minimal time lags. Then, the results are extended to networks with fuzzy durations.Project management and scheduling Fuzzy intervals Fuzzy PERT/CPM

Application of Duration Measure in Quantifying the Sensitivity of Project Returns to Changes in Discount Rates

In this research, the concept of Duration with a new application in project management has been defined. The Duration of each project provides the project manager with a combined measure containing concepts of return, cost and time of the project. Further in this article, the changes in project return, based on different assumptions such as discount rate, have been examined. To examine the effect of the changes in these factors, the Monte Carlo simulation has been used. The relationship between these factors is nonlinear which reflects the great importance of investment on appropriate risk management systems. The data from a set of construction projects have been used in order to verify the results of this study. Similar relationships can be expected to exist in other industries as well.This article belongs to the Special Issue Rational Decision Making in Risk Managemen

Combining Monte Carlo Simulation and Bayesian Networks Methods for Assessing Completion Time of Projects under Risk

In this study, Monte Carlo simulation and Bayesian network methods are combined to present a structure for assessing the aggregated impact of risks on the completion time of a construction project. Construction projects often encounter different risks which affect and prevent their desired completion at the predicted time and budget. The probability of construction project success is increased in the case of controlling influential risks. On the other hand, interactions among risks lead to the increase of aggregated impact of risks. This fact requires paying attention to assessment and management of project aggregated risk before and during the implementation phase. The developed structure of this article considers the interactions among risks to provide an indicator for estimating the effects of risks, so that the shortage of extant models including the lack of attention to estimate the aggregated impact caused by risks and the intensifying impacts can be evaluated. Moreover, the introduced structure is implemented in an industrial case study in order to validate the model, cover the functional aspect of the problem, and explain the procedure of structure implementation in detail.This article belongs to the Special Issue Occupational Safety and Risks in Constructio

Identifying program critical success factors in construction industry

In project management literature, the concept of program is a group of related projects managed in a coordinated way to obtain benefits not available from managing them individually. This paper attempts to identify program critical success factors focusing on Iran’s construction industry so that the level of relative importance of various factors could be determined for key stakeholders. Furthermore, since a program includes a set of projects, another objective of this study is to find out whether the projects of program are accomplished, successfully or not. Therefore, to run this study, first literature of topic based on research keywords is reviewed. Then a conceptual model including all the aspects of program success factors is presented. Next, critical success factors are quantitatively analyzed by performing an empirical investigation on active organizations and firms of Iran’s construction industry. The study employs questionnaire and performs interview surveys with construction program professionals and experts. Finally, the critical success factors of program are sorted according to their ranks. The results show that program-related factors maintain the highest effects on program success followed by organization-related and project-related issues

The impact made on project portfolio optimisation by the selection of various risk measures

This study addresses the effect of selecting an appropriate risk measure and the impact of this choice on the efficient frontier of the project portfolio of an organisation. The appropriate choice of a firm’s project portfolio has a great impact on the organisational success. Each portfolio manager selects the best projects with different criteria and consistent with firm’s strategic objectives. We used the Markowitz efficient frontier method to select the best projects of the organisation. The choice of proper measures impacts on this decision and can change the organisation’s portfolio. The standard deviation was applied, and the relevant optimisation was made for this purpose. Then, the semi-standard deviation was used to differentiate between favourable and unfavourable opportunities. Afterwards, Value at Risk and Expected Shortfall were applied as appropriate risk measures to make a better estimate of the tail risks. All these risk measures were used to select the best possible projects. Managers should select the appropriate risk measures according to their objectives, estimation of their project distribution, and characteristics of the projects. This research studied the best measures consistent with construction projects and the effect of changes in these measures