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on Project, Program and Portfolio Management |
| By: | M. VANHOUCKE |
| Abstract: | In this paper, we present a new genetic algorithm for the resource-constrained project scheduling problem with discounted cash flows and investigate the trade-off between a project’s net present value and its corresponding lead time. We consider a problem formulation where the pre-specified project deadline is not set as a hard constraint, but rather as a soft constraint that can be violated against a certain penalty cost. The genetic algorithm creates children from parents taken from three different populations, each containing relevant information about the (positive or negative) activity cash flows. We have tested various parent selection methods based on four crossover operators taken from literature and present extensive computational results. |
| Keywords: | Resource-constrained project scheduling; net present value; genetic algorithm |
| Date: | 2007–03 |
| URL: | http://d.repec.org/n?u=RePEc:rug:rugwps:07/456&r=ppm |
| By: | M. VANHOUCKE |
| Abstract: | Time/cost trade-offs have been extensively studied in the literature since the development of the critical path method. Recently, the discrete version of the problem formulation has been extended to various practical assumptions, and solved with both exact and heuristic optimization procedures. In this paper, we present a electromagnetic meta-heuristic (EM) algorithm for the discrete time/cost trade-off problem under four different assumptions. We extend the standard electromagnetic meta-heuristic with problem specific features and investigate the influence of various EM specific parameters on the solution quality. We test the new meta-heuristic on a benchmark set from the literature and present extensive computational results. |
| Keywords: | discrete time/cost trade-off problem; work continuity; time/switch constraints; net present value; electromagnetism |
| Date: | 2007–04 |
| URL: | http://d.repec.org/n?u=RePEc:rug:rugwps:07/457&r=ppm |
| By: | Yuval Emek; Michal Feldman |
| Abstract: | We study an economic setting in which a principal motivates a team of strategic agents to exert costly effort toward the success of a joint project. The action taken by each agent is hidden and affects the (binary) outcome of the agent's individual task stochastically. A Boolean function, called technology, maps the individual tasks' outcomes into the outcome of the whole project. The principal induces a Nash equilibrium on the agents' actions through payments that are conditioned on the project's outcome (rather than the agents' actual actions) and the main challenge is that of determining the Nash equilibrium that maximizes the principal's net utility, referred to as the optimal contract. Babaioff, Feldman and Nisan [1] suggest and study a basic combinatorial agency model for this setting. Here, we concentrate mainly on two extreme cases: the AND and OR technologies. Our analysis of the OR technology resolves an open question and disproves a conjecture raised in [1]. In particular, we show that while the AND case admits a polynomial-time algorithm, computing the optimal contract in the OR case is NP-hard. On the positive side, we devise an FPTAS for the OR case, which also sheds some light on optimal contract approximation of general technologies. |
| Date: | 2007–05 |
| URL: | http://d.repec.org/n?u=RePEc:huj:dispap:dp452&r=ppm |
| By: | Stephen V. Burks (University of Minnesota, Morris, and IZA); Jeffrey Carpenter (Middlebury College and IZA); Lorenz Götte (Federal Reserve Bank of Boston and IZA); Kristen Monaco (California State University, Long Beach); Kay Porter (Cooperating Motor Carrier); Aldo Rustichini (University of Minnesota) |
| Abstract: | The Truckers and Turnover Project is a statistical case study of a single firm and its employees which matches proprietary personnel and operational data to new data collected by the researchers to create a two-year panel study of a large subset of new hires. The project’s most distinctive innovation is the data collection process which combines traditional survey instruments with behavioral economics experiments. The survey data include information on demographics, risk and loss aversion, time preference, planning, non-verbal IQ, and the MPQ personality profile. The data collected by behavioral economics experiments include risk and loss aversion, time preferences (discount rates), backward induction, patience, and the preference for cooperation in a social dilemma setting. Subjects will be followed over two years of their work lives. Among the major design goals are to discover the extent to which the survey and experimental measures are correlated, and whether and how much predictive power, with respect to key on-the-job outcome variables, is added by the behavioral measures. The panel study of new hires is being carried out against the backdrop of a second research component, the development of a more conventional indepth statistical case study of the cooperating firm and its employees. This is a high-turnover service industry setting, and the focus is on the use of survival analysis to model the flow of new employees into and out of employment, and on the correct estimation of the tenureproductivity curve for new hires, accounting for the selection effects of the high turnover. |
| Keywords: | field experiment, risk aversion, loss aversion, time preference, IQ, MPQ, numeracy, U.S. trucking industry, for-hire carriage, truckload (TL), driver turnover, employment duration, survival model, tenure-productivity curve |
| JEL: | C81 C93 L92 J63 |
| Date: | 2007–05 |
| URL: | http://d.repec.org/n?u=RePEc:iza:izadps:dp2789&r=ppm |
| By: | Andreas Kontoleon (Department of Land Economy, University of Cambridge, UK); Pauline Grosjean (LERNA, University of Toulouse and European Bank for Reconstruction and Development, France) |
| Abstract: | This paper undertakes a direct comprehensive assessment of the long-run sustainability of one the world’s largest sustainable development programs, the Slopping Land Conversion Program (SLCP) in China under different plausible post-SLCP scenarios. The analysis is based on farmer contingent behavior post-program land and labor decisions as well as choice experiment data. Our econometric results highlight the main obstacles to the program’s sustainability, which include specific shortfalls in program implementation as well as certain institutional constraints such as tenure insecurity, poor land renting rights, limited access to credit and limited land management rights. |
| Keywords: | sustainable development programs, sustainability, recursive probit, choice modeling, Asia, China |
| JEL: | Q2 Q4 R4 |
| Date: | 2007 |
| URL: | http://d.repec.org/n?u=RePEc:lnd:wpaper:200726&r=ppm |
| By: | Broberg, Thomas (Department of Economics, Umeå University) |
| Abstract: | This paper estimates the public benefit of preserving 126 000 hectares of old-growth forest in the sub-mountainous region of Sweden through contingent valuation. The primary benefit of this in-situ conservation of biodiversity is the forest’s relative diversity and richness, which provides important habitat for threatened species. Thus, benefits arise predominantly from nonuse values. We find that a majority of the Swedish population is unwilling to contribute financially to the preservation project (median WTP equals zero). The estimated mean WTP is SEK 300, implying an aggregate benefit of SEK 9 billion. We estimate two types of valuation functions in order to reject the hypothesis that respondents state random numbers as their WTP. Firstly, a binary logit model indicates that variables related to a respondent’s education level, income level and concern about the environment are positively correlated with the likelihood of supporting the preservation project, while being a male and having an anti-environmental attitude towards public expenditures are negatively correlated. After controlling for whether or not locals are employed in forest-related industries, we find that locals, in general, are more likely to have a positive WTP. Secondly, we estimate a valuation function conditioned on respondents with a positive WTP and find that the size of their contribution is explained by income, general concern about the environment, and the motive underlying their valuation (e.g., use versus nonuse). No differences between locals and non-locals were found. |
| Keywords: | contingent valuation; willingness to pay; social benefit; nonuse values; non-timber value; old-growth forest; preservation; conservation |
| JEL: | Q20 Q23 Q26 Q28 Q38 |
| Date: | 2007–05–16 |
| URL: | http://d.repec.org/n?u=RePEc:hhs:umnees:0712&r=ppm |
| By: | Paunić, Alida |
| Abstract: | Making the taxes acceptable to large number of people by allocating their obligation to the chosen project is the main subject of this paper. In this way a greater objectivity, transparency and local goals are set in according to the preferences of the tax contributors. State Investment office prevents the rule of invisible hand of market by allocation part of tax money to the less developed regions reducing difference between them. |
| Keywords: | tax; principal agent problem; welfare |
| JEL: | D61 H00 D72 |
| Date: | 2007–05 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:3151&r=ppm |