Assignment #1

Review Article 1

1) Article Reference
Liebman, Jon (1976) “Some simple-minded observations on the role of optimization in public systems decision making” Interfaces 6 (4) pp. 102-108

2) Summary
This paper was written in 1976 and presents a very good overview on the constrains for the application of optimization (in this case could be: modeling, operations research, system analysis) in the public sector. The author provides some definitions of public sector and two specific examples of applications by the NY fire department and for a watershed water quality plan.
The main point of the paper is to present the crucial difference in applying optimization to solve wicked and unwicked problems. To clarify the understanding of wicked problems, I´m considering the wikipedia definition “Wicked problem is a phrase used in social planning to describe a problem that is difficult or impossible to solve because of incomplete, contradictory, and changing requirements that are often difficult to recognize. Moreover, because of complex interdependencies, the effort to solve one aspect of a wicked problem may reveal or create other problems.”
According to the author, usually in the past, optimization procedures could have been solved using linear programming methods such as the Simplex method. By this time the analyst had the simple task of processing many alternatives to find the best solution. The author consider that the decision makers in the private sector organizations have often the some goals and objectives, which makes the role of optimization a lot easier and direct. But in the case of the public sector, considering the existence of many different stake-holders, and even the difference between individuals, there are many goals which can be completely different from each other, characterizing a conflict, resulting often in two groups, the winners and the losers.
Optimization procedures have evolved a lot since the limitation of non-linear problems but the increasing perception of the complexity evolved in most of public decision making processes have showed that “optimization can only be useful when the goals are clear and explicit”. Considering that, the author states that instead of “The role of optimization and modeling in nonwicked problems is the selection of a solution among alternatives” is switching to “The role of optimization and modeling in wicked problems is the formulation of alternatives rather than the selection of one of them”. Even though a direct use of optimization models is not appropriate to wicked problems, those models can have a great value for illuminating the conflict, for example: expanding the problem understanding, to formulate alternatives or even to evaluate scenarios.

3) Discussion
a) I think the paper represents a very good overview from the 80´s about the constrains of the application of optimization models to complex or wicked problems. Considering the use of optimization trough history, the author points a moment in time where society is finding that optimization models are as good as the goals provided to them. If the decision makers don’t agree with the some goals, optimization procedures can´t be set to solve them.
b) I don’t see many limitations on this work, as I think is hard to tell what was the reality or the understanding of complex problems by that time.
c) If this where my research I would focus in the point of finding benefits and trying to develop specific applications to improve decision making with optimization models in wicked problems. That would include conflict resolution and processes that try to find the best for all, minimizing the existence of the winner/losers distinction. I find this a very interesting research topic.

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Review Article 2

1) Article Reference

Karterakis, S., M.; Karatzas, G., P.; NIKOLOS, I., K. and Papadopolou, M., P. (2007) “ Application of linear programming and differential evolutionary optimization methodologies for the solution of coastal subsurface water management problems subject to environmental criteria” Journal

2) Summary

This paper presents an application of optimization methods to solve groundwater management’s problems including environmental criteria. The authors used linear programming and differential evolutionary methods. This study is applied to the coastal region of Hersonissos, Crete.
A comprehensive literature review about optimization applications for environmental issues is presented. To approach the conceptual model and develop the physical model a characterization of the study area is provided among the theoretical concepts used for the simulation of seawater intrusion phenomenon (Sharp interface approach).
The goal of the optimization is to maximize the total extracted water from five selected pumping locations. The constrains are to ensure no further intrusion of the seawater front at ten selected observation well were the calculated hydraulic head should be greater than 102.5m at the end of the 10 year management period.
A brief overview and literature review of linear programming (the simplex method) and heuristic optimization (differential evolution algorithm) is provided. The solutions of the simulations with both methods are compared. A extensive sensitivity analyses is also provided.
The main conclusion for this case study both methods had very similar results, by the exception of one well. The simplex method had much less computer time demand but needs a constantly interaction worth the user and the heuristic methods although requires much more computer time is completely automated.

3) Discussion
I felt really enthusiastic seeing that the Journal of Hydrology is currently publishing applications of optimization procedures for water resources management problems. This is particularly interesting in the sense to show the importance of the subject for my research. I think maybe more management alternatives could have been analyzed. To improve the research I would try different optimization approach and enlarge the alternative scenarios.