Showing papers by "International Institute for Applied Systems Analysis published in 1984"

The institutional context of science, models, and policy: The IIASA energy study

Abstract: This article is a complement to Keepin's technical analysis of the energy models and scenarios in the IIASA global energy study, Energy in a Finite World. It analyses the role of formal global energy models in the scenarios and policy conclusions as described in the IIASA Energy System Program's (ESP) own statements. It finds inconsistencies which have confused external audiences, including modelers, as to the importance of properties of formal models in generating authority for policy conclusions. The analysis finds two contradictory images of scientific authority pervading the ESP's published accounts. This article argues that models are more symbolic vehicles for gaining authority than objective technical frameworks. Whilst this is in principle legitimate, it means that the internal processes (and not just the products) of modeling projects are a legitimate subject of public evaluation. Due attention must therefore be paid to the quality and disclosure of such processes. The institutional process of analysis reflects a particular policy style itself and constrains what policies are even conceivable. Claims to scientific analysis and definition of policy problems are themselves symptomatic of a policy framework which is biased at a deeper level than that of specific prescriptions.

Among the Energy Tribes: A cultural framework for the analysis and design of energy policy

Abstract: My four years at the International Institute for Applied Systems Analysis (IIASA) have provided the opportunity for some participant observation among the Energy Tribes. The uncertainties that envelop trends in energy supply and demand are so wide that the exploratory mode (asking “What would you like the facts to be?”) turns out to be more rewarding than the adversary mode (asking “What are the facts?”). The three Energy Tribes are distinguished by their three contradictory scenarios: “Business as Usual,” “Middle of the Road” and “Radical Change Now.” Each scenario sets very different bounds on what is credible and incredible, possible and impossible, sensible and foolish, rational and irrational.

DIDASS — Theory, Implementation and Experiences

Abstract: The purpose of this paper is to report on the progress made in the System and Decision Sciences (SDS) research group at IIASA on the development of the decision support system DIDASS (Dynamic Interactive Decision Analysis and Support System). This system is based on methodology derived from the paradigm of satisficing decision making and the methodology of linear and nonlinear programming. The mathematical background to this approach (based on aspiration formation and the concept of scalarizing functions) is outlined in Section 2. Methods of implementation and computational aspects are discussed in Section 3. The fourth section summarizes three applications of DIDASS, and the paper ends with some conclusions.

A technical appraisal of the IIASA energy scenarios

Abstract: Several shortcomings in a major study of the world's energy system are described. The study, entitled Energy in a Finite World, resulted in widely publicized conclusions and urgent policy recommendations that were derived from detailed projections of the global energy future. A set of computer models was used to produce these projections, which are analyzed here in two ways. First, treating the models as a black box, it is shown that several principal results are effectively prescribed informally in input data that pass through the models unchanged. Second, despite claims of robustness, detailed sensitivity analysis shows that the energy supply projections are highly sensitive to perturbations in various input data. Early work that revealed this problem is not cited, and standard sensitivity tests are not provided in the study. Thus, despite the appearance of analytical rigor, the study's conclusions are evidently based on opinions rather than objective robust analysis.

A Decision-Process Perspective on Risk and Policy Analysis

Abstract: Risk analysis and policy analysis can play important roles in facilitating the siting of potentially hazardous facilities if one recognizes the descriptive features of the decision process. The case of siting a liquified natural gas LNG facility in California illustrates the multi-party sequential nature of the process and the role that widely differing risk estimates play in fueling conflicts between stakeholders. Risk analysis does have a useful function in clarifying the nature of the potential losses, particularly if rules of evidence are instituted for evaluating different studies. Policy analysis can facilitate the negotiation process by the use of compensation to redistribute gains and losses between the different parties. Examples from case studies are presented to illustrate the challenges for risk analysis and policy analysis in the siting process.

Interactive decision analysis and interpretative computer intelligence

Abstract: This paper presents a unifying approach to the issue of using computers and computerized mathematical models for decision analysis and support. The interpretative aspect of computer intelligence is an essential part of this approach; this paper presents a mathematical formalization of this aspect. Another essential part of this approach is a proposal to integrate the three major formalized frameworks for rational decision making: utility theory (mostly normative), aspiration theory (mostly behavioral), and the (mostly hierarchical) theory of goal- and program-oriented management. These two elements lead to the formulation of principles for a broad class of decision support systems, which includes many existing systems but which also opens new possibilities. Two main cases of decision support are discussed: joint decision making (i.e., involving only one decision maker or several decision makers who have to reach a consensus) and independent decision making (assuming a game-like situation with several decision makers). These cases are illustrated by reference to the DIDASS system, its applications and extensions.

Modeling and solution strategies for unconstrained stochastic optimization problems

Abstract: We review some modeling alternatives for handling risk in decision-making processes for unconstrained stochastic optimization problems. Solution strategies are discussed and compared.

Simple models, catastrophes and cycles

Abstract: It is often observed in practice that the essential behavior of mathematical models involving many variables can be captured by a much smaller model involving only a few variables. Further, the simpler model very often displays oscillatory behavior of some sort, especially when critical problem parameters are varied in certain ranges. This paper attempts to supply arguments from the theory of dynamical systems for why oscillatory behavior is so frequently observed and to show how such behavior emerges as a natural consequence of focusing attention upon so‐called “essential” variables in the process of model simplification. The relationship of model simplification and oscillatory behavior is shown to be inextricably intertwined with the problems of bifurcation and catastrophe in that the oscillations emerge when critical system parameters, i.e. those retained in the simple model, pass through critical regions. The importance of the simplification, oscillation and bifurcation pattern is demonstrated here by consideration of several examples from the environmental, economic and urban areas.

An alternative variational principle for variable metric updating

Abstract: We describe a variational principle based upon minimizing the extent to which the inverse hessian approximation, sayH, violates the quasi-Newton relation, on the step immediately prior to the step used to constructH. Its application to the case when line searches are exact suggests use of the BFGS update.

Simulation of an Interactive Method Supporting Collective Decision Making Using a Regional Development Model

Abstract: This paper deals with a computerized interactive system which supports the making of collective decisions in a gaming framework. The basic idea of the system was proposed by Wierzbicki (1982), although several modifications have also been tested. The system has been implemented for a simple decision problem concerning the allocation of funds for regional development.

ON ENERGY SYSTEMS IN HISTORICAL PERSPECTIVE: The Last Hundred Years and the Next Fifty

Abstract: Volterra-Latka equations are used to reduce primary energy statistics to simple forms, useful for understanding the past and predicting the energy trends of countries and the world.

Economics and Politics of Information Technology: Some Trends in its Application to Information for the Professional

Abstract: Dans cette vue d'ensemble des aspects politiques et economiques de l'application des nouvelles technologies, on traite plus particulierement les questions suivantes: le cout de l'information en ligne, l'opposition service public ― service commercial, l'opposition entre les gros systemes et les systemes specialises, le protectionnisme ou la libre circulation des produits d'information, les perspectives ouvertes par la fourniture electronique des documents

A posteriori trade-off analysis in reference point approaches

Abstract: This paper is concerned with extensions to existing reference point methods for multiple objective decision making (MODM) through the incorporation of an a-posteriori trade-off analysis, i.e. an examination of the tradeoffs between objectives which are implied by a given, tentative solution to the problem under consideration. The term reference point method is used in this context to include both conventional goal programming approaches, where the reference point represents the decision maker’s actual aspiration levels (cf. Lee 1972; Ignizio 1976), and the more recent interactive procedures where the reference point is used as a primarily technical means of exploring the feasible region (Wierzbicki 1979a, 1979b; Lewandowski and Grauer 1982).

Strategies for assessing impacts of climatic change in marginal areas

Abstract: Greater rigour is required in designing research strategies to assess possible impacts of climatic change on society We can identify relatively disadvantaged or marginal areas which may be particularly sensitive to climatic fluctuations This vulnerability to climate is best described as a level of risk of significant impact, eg crop failure Changes in climate are accompanied, therefore, by changes in the level of risk These changes may be very rapid in marginal areas and are characterised by a very steep, quasi-exponential “risk-surface” With suitable models linking climate to crop growth potential, boundaries of agroclimatic risk can be mapped geographically Temporal shifts of these boundaries identify areas of potential impact The approach is illustrated in examples from North America and Northern Europe

Energy Supply Model Message and Its Application to IIASA’s World Region V

Abstract: The energy supply model MESSAGE (Model for Energy Supply Systems and Their General Environmental Impact) is a dynamic linear programming (DLP) model which minimizes total discounted costs of energy supply over a given time horizon. The main subject of the model is the balancing of demand for secondary energy and supply of primary energy resources via a menu of technologies. The most important model constraints reflect limits on the speed of buildup of technologies, the availability of indigenous and imported resources, and technological relationships. The model considers load regions for electricity demand, disaggregates resources into cost categories, and calculates environmental impacts of energy supply strategies. The model output is used to describe scenarios of energy supply. These scenarios account for the physical flows of energy between primary energy and end use; shadow prices of supply and demand constraints; and environmental impacts of energy supply paths, expressed as emissions and concentrations of pollutants.

A model for the location and sizing of many interlinked health care specialities and some empirical results

Abstract: This paper describes in non technical terms a new model, recently developed by the authors, which generalizes in several ways the traditional health care facility location models (Clarke,Wilson,1983; Mayhew,Taket,1980; Tadei, Gallino, Salomone, 1983; Wilson, Clarke, 1982). First, a multi-specialty structure is explicitly introduced,so that bundles of specialties, rather than aggregate hospital beds,are allocated over space. Secondly, patients are introduced in terms of their patient history, that is, each patient is associated with a sequence of stays in and transitions among different specialties and locations. This introduces interactions among all specialties and locations. Third, the evaluation and choice process associated with each patient history is treated as a stochastic multistage decision process, based on nested random utility theory (Bertuglia, Leonardi, Tadei, 1983; De Palma, Ben-Akiva, 1981; Domencich, McFadden, 1975; Leonardi, 1983; Leonardi, Campisi, 1981; Leonardi, Tadei, 1981; McFadden, 1978).

Models of Risk Group Dynamics

Abstract: The susceptibility of individuals to various forms of morbidity and mortality may change over time due to changes in individuals’ behavior, occupation, etc., as well as environmental changes. In some instances it is useful to classify individuals into risk groups and to analyze the dynamics of the changing proportion of individuals in the various groups. These dynamics may be important in evaluating alternative health strategies.