Multiple resources allocation under stochastic conditions on projects with multimodal activities

A “multi-modal” activity is one which can be performed in several modes, or levels, of resource(s) allocation. In this paper we assume that the activities are multi-modal, and each activity may require several resources for its execution. We also assume that the resources may be constrained on their availability over time, and that each activity has its own work contents as a continuous random variable for each of its required resources. We are concerned with establishing a suitable strategy that will focus on the universe of activity modes, selecting only those that will be relevant for the most probable overall project cost. In other words, we choose the most probable modes of activity execution among the theoretical continuum of modes; and propagate the consequences of that choice throughout the project. The proposed approach relies on the partitioning of the work content domains into classes. Using these classes, we address different probabilities for each feasible allocation.Fundação para a Ciência e a Tecnologia (FCT

Utilização de ferramentas informáticas na gestão de projectos

A gestão de projectos tem-se tornado uma disciplina fundamental nas organizações, na medida em que o mercado está cada vez mais competitivo. Com a crescente preocupação em entregar os projectos dentro dos prazos estipulados, com qualidade e dentro do orçamento previsto, é fundamental a utilização de ferramentas informáticas. Actualmente, é praticamente impensável gerir um grande projecto sem o apoio de um suporte informático, quer devido à sua dimensão, quer à sua complexidade. Mesmo para projectos mais simples, fazer alterações e actualizar toda a rede, é algo difícil de ser feito sem o apoio de ferramentas informáticas. Neste artigo serão apresentadas algumas ferramentas informáticas que são actualmente usadas no apoio à gestão de projectos e é feita a sua análise no que diz respeito a benefícios que estas possam trazer, de forma a conduzirem a um melhor desempenho na gestão global de um projecto.Fundação para a Ciência e a Tecnologia (FCT

Concurrency detection on finish-to-start activity precedence networks

We explore the finish-to-start precedence relations of project activities used in scheduling problems. From these relations, we devise a method to identify groups of activities that could execute concurrently, i.e. activities in the same group can all execute in parallel. The method derives a new set of relations to describe the concurrency. Then, it is represented by an undirected graph and the maximal cliques problem identifies the groups. We provide a running example with a project from our previous studies in resource constrained project cost minimization together with an example application on the concurrency detection method: the evaluation of the resource stress

A multicriteria decision aid software application for selecting MCDA software using AHP

In the business world, a good decision may be the success of an organization. To decide, sometimes, is not an easy task, mainly when we have multiple criteria. A bad decision can mean the collapse of an organization. In the current climate of turbulence, the companies, in order to become competitive in an increasing demanding market, have to know how to make decisions right. This work begins to present a review of the literature on the main techniques proposed in multicriteria decision making. Then it presents the results of a research on the software tools available in this field. These software tools were then characterized and classified and their main characteristics summarized. The next step was to construct a software application to help organizations in the selection of the right multicriteria Decision Aid (MCDA) software available, among the ones previously collected. The multicriteria technique used for the selection was the Analytic Hierarchy Process (AHP) from Saaty. The programming language used to develop the application was Microsoft Visual Basic 2008 Express Edition. The software tool developed allows the user to access all the information about the software tools available, showing the web page of each application and allowing one to view other related information. The criteria selected were: "Compatibility between Operating Systems", "Cost of a License", "Interaction with user", "User Manual and Tutorials", "Application Examples", "Online Help" and finally "Free Version". After inserting the pairwise comparisons required by the AHP between pairs of criteria, the software is able to select the best alternative software tool among the ones available. An example application of the algorithm is presented to illustrate the use of the program.Fundação para a Ciência e a Tecnologia (FCT

The application of a decision model in the management of raw material costs

The management of raw material costs is of most importance, especially when it represents a considerable part of the industrial costs, when the price of raw materials is very volatile and the acquisition of raw materials has operational and strategic implications. However, most companies do not support the purchasing process of raw materials with models and procedures properly structured. Thus, supplier selection, the timing of the acquisition, and the quantity and allowable price of raw material ask for appropriate decision models which support a better cost management of raw material. In this paper the main focus is to explain the developed method used to identify the best conditions for the acquisition of raw materials. The problem was to analyze several criteria such as: price, delivery time, credit line and how much time is needed for the delivery of raw materials, considering some suppliers. As the solutions needs to be sustained by a mathematical method including future choices, the development requires cooperation between the researcher and the actors involved in searching the solutions. Based on an approach that combines decision trees, developed using Precision Tree software, and multicriteria models, the method, validated and tested, allows the decision maker to consider various criteria for selecting a supplier. The use of the decision tree developed turned possible to determine the supplier who offers the best overall expected value. The model developed in Flexus S.A. gained wide acceptance by the managers and it is used to make procurement decisions of raw materials for its agility and easy understanding. Furthermore, the application of the model allowed Flexus S.A. to initiate trade relations with suppliers who had not been previously considered. This change allowed the company to increase responsiveness to customer needs

Capture and maintenance of project total cost minimization applications’ results

In the past several years, various optimization algorithms had been implemented on the project total cost minimization problem. Lately, it was developed an application that serves as a central platform that integrates all those previous implementations. Currently, such platform allows the access and execution of each one of the other utilities as modules/plugins. Each of which can be configured to execute optimizations over different projects. Although the platform already saves the optimization results, it lacks a suitable processing mechanism that would ease the cross analysis over all the utilities. Therefore, we want to include capture and analysis of results into the platform in order to properly aggregate them in a results database. Such database could then be queried for numerous purposes being the performance evaluation, across the optimization utilities, one of the first. In this project we analyze a total of five heterogeneous optimization utilities, all coded in JAVA, using algorithms based on dynamic programming and global optimization. The heterogeneity poses a challenge which we overcame by establishing a common results storage language, by means of XML files.Fundação para a Ciência e a Tecnologia (FCT

Preliminary research plan towards a project and portfolio management framework to support innovation-driven SMEs

Despite the different business models and frameworks used currently in the industry, there is still a lack of a robust single roadmap that is dedicated to small and medium-sized enterprises which combines the applicable concepts of portfolio management and innovation management at the same time, and provide SMEs with an integrated feature to assist them in selecting and managing the best mix of innovative projects inside one business portfolio, using the most optimized methods. This unique integrated framework shall be the ultimate goal of our research work associated with other sub-goals and sub-objectives throughout the two upcoming years. The research will take the form of “applied research” following a deductive logic roadmap in order to reach our final outcome. More than one aspect regarding our research shall be clarified as we move on with the next stage of the work such as choosing a specific industry from which our sample will be selected

Gestão de projectos: alocação adaptativa de recursos em redes de actividades multimodais

Nas últimas décadas a gestão de projectos tem-se revelado um instrumento poderoso que permite às organizações enfrentar novos desafios, como a competitividade dos mercados globais e a consequente necessidade da diminuição das margens de lucro. Com o aumento do tamanho e da complexidade dos projectos, o seu planeamento e controlo tornou-se uma das mais importantes tarefas de gestão. No processo de planeamento do projecto, os gestores têm de lidar com a incerteza e necessitam manipular a alocação dos seus recursos adaptativamente, por forma a alcançar os seus objectivos. Contudo, tratamentos do bem conhecido problema de alocação de recursos a projectos têm sido determiní­sticos e estáticos, e tratam na sua maioria actividades unimodais. Nesta tese é apresentada uma abordagem à alocação de recursos sob condições estocásticas, para redes de actividades multimodais. A optimização é feita utilizando programação dinâmica, que demonstrou ser, como se esperava, exigente em termos computacionais. Neste sentido foram analisados esquemas de aproximação que não se afastam significativamente do óptimo, mas são mais modestos em termos computacionais. É também estudada a aplicação de uma técnica de optimização global baseada numa modificação do algoritmo "Electromagnético" de Birbil e Fang [BirbilFang00].In the last decades, project mariagement has revealed it self a powerful tool, which allows organizations to face new challenges, like the competitivity of global markets and the consequent necessity of decreasing profit margins. With the increase of the project size and complexity, planning and control has become one of the most important management tasks. In practice, project managers inputs cope with uncertainty, and must manipulate the allocation of their resources adaptively in order to achieve their ultimate objectives. Yet, treatments of the well-known 'resource constrained project scheduling problem' have been deterministic and static, and have addressed most unimodal activities. We present an approach to resource allocation under stochastic conditions for multimodal activity networks. Optimization is via dynamic programming, which proves to be demanding computationally, as expected. We investigate approximation schemes that do not detract significantly from optimality, but are modest in their computational requirements. We also investigate the application of a global optimization technique based on a modification of the "Electromagnetic" algorithm of Birbil and Fang [BirbilFang00].Universidade do Minho; Programa PRODEP; Fundação Calouste Gulbenkian; Fundação Luso-Americana para o desenvolvimento

On the multi-mode, multi-skill resource constrained project scheduling problem (MRCPSP-MS)

In this paper we describe an extension of the Resource-Constrained Project Scheduling Problem (RCPSP). A literature review is presented to place our research in its proper context. The problem presented here belongs to the class of the optimization scheduling problems with multi-level (or multi-mode) activities. This means that the activities can be scheduled at different modes, each mode using a different resource level, implying different costs and durations. Each activity must be allocated exactly one unit of each required resource and the resource unit may be used at any of its specified levels. The processing time of an activity is given by the maximum of the durations that would result from a specific allocation of resources. The objective is to find the optimal solution that minimizes the overall project cost, while respecting a delivery date. A penalty is included for tardiness beyond the specified delivery date. We present a formal description of the problem and a mathematical model for it. We also introduce the implementation algorithm for the problem. The implementation was designed using the JAVA language, and the algorithm proposed is based on a branch and bound procedure, using breadth-first search (BFS) project network traversing, among some heuristic rules to filter large subsets of fruitless candidates relative to resource levels combinations.Fundação para a Ciência e a Tecnologia (FCT

On the multi-mode, multi-skill resource constrained project scheduling problem : computational results

This paper is concerned with an extension of the Resource-Constrained Project Scheduling Problem (RCPSP) which belongs to the class of the optimization scheduling problems with multi-level (or multi-mode) activities. We developed a practical tool, useful to represent multi-mode projects, and to find a solution for the problem on hand – select the best mode for each resource in each activity in order to minimize the total cost, considering the resource cost, a penalty for tardiness and a bonus for early completion. We implemented an adaptation of a filtered beam search (FBS) algorithm to this problem, using the C# programming language. A “filtered beam” search is a heuristic Branch and Bound (BaB) procedure that uses breadth first search but only the top “best” nodes are kept. We give some of the most important solution details and we report on further computational results, by testing the application for different problem sizes