Showing papers by "International Institute for Applied Systems Analysis published in 1983"

Uncertainty, System Identification, and the Prediction of Water Quality

Abstract: There would be little disagreement among water quality modelers with the opinion of Orlob (1983a) that virtually all the significant developments since the (now) classical work of Streeter and Phelps (1925) have occurred within the past two decades. During the 1960s and early 1970s there was a very substantial investment in model-building associated with water quality management projects, particularly in the United States. The main legacy of this initial investment is a well-established interest in the development of progressively larger and more complex simulation models. “Large” is admittedly a rather imprecise description of a model, although a glance at some of the recent literature on water quality modeling will give some impression of the intended meaning (for example, Russell, 1975; Patten, 1975, 1976; Jorgensen and Harleman, 1978; Scavia and Robertson, 1979). There is no doubt that the immense scope for complex system simulation created by the advent of electronic computers has fostered the rapid growth of “large” water quality models.

Migration and settlement: a multiregional comparative study.

Abstract: In 1976, the International Institute for Applied Systems Analysis initiated a study of migration and population distribution patterns in its seventeen member nations. In each country, the analysis was carried out by national scholars using techniques of multiregional demography. In this paper the authors describe the organization of the study, discuss the data bases used, evaluate the main results obtained, and review some of the methodological research that has been generated by the study. Among the author's conclusions are recommendations for researchers wishing to carry out a multiregional demographic analysis.

An Optimal Control Representation of a Stochastic Multistage-Multiactor Choice Process

Abstract: This paper considers a multiactor decision process, where each actor chooses a sequence of actions over time, in order to maximize his utility, subject to a random noise in the utility evaluation. The pool of alternative actions is limited, and all actors compete to use these alternatives, thus generating mutual externalities due to shortages. This process, which has a direct formulation in terms of a nested random utility model, is shown to be equivalent to a suitably built optimal control problem, whose Hamiltonian can be interpreted as a total benefit. A continuous time formulation is outlined, and an application to modelling residential mobility is discussed.

A Monte Carlo Approach to Estimation and Prediction

Abstract: The model representation of complex environmental systems requires numerous simplifications; frequently, arbitrary choices of how to formally represent the relationships between causes and effects have to be made, since these relationships are neither obvious nor easy to detect. Environmental systems in toto do not easily yield to the classical scientific tool of planned experimentation. Consequently, the analyst has to utilize whatever bits of information may be available, which as a rule are very few and not strictly appropriate in terms of the problems addressed. A priori knowledge about the structure and function of any ecosystem is generally poor, and reliable quantitative information on the governing processes and their rates and interrelationships insufficient. Consequently, building and testing models and finally applying them for predictive purposes often consists of a more or less formalized trial-and-error iterative process of estimation, testing, and improvement. The following discussion proposes an approach for formalizing this process of model building, calibration, and application; it emphasizes the interdependences of the individual steps in the process. The approach proposed is based on the recognition of uncertainty as an inevitable element in modeling, and uses straightforward Monte Carlo techniques to cope with this uncertainty.

Reference Point Optimization — The Nonlinear Case

Abstract: This paper is concerned with the interactive use of a multicriteria programming package for multicriteria decision support. The approach is based on the reference point method. Implementation of the system in the multicriteria nonlinear programming case is discussed, and basic features of the user — computer interface are presented.

A method for disaggregate household forecasts.

Abstract: A method for making household forecasts is proposed "which yields both the total number of households and the number present in any predetermined subgroup of households. The method presupposes that incomplete information is available on the transitions of persons between various age and household categories over a period of time. The forecasting method is capable of spelling out the consequences for the prognoses of adding different amounts of external information to the computations. Such information may include population forecasts by age and sex trend-based information like restrictions on the size distribution of households econometric relations between household formation and incomes etc." The forecasting method is described in theoretical terms. "This description includes the use of information-theoretic arguments to adjust the forecast to external data. The theoretical development is illustrated by an application of the method to data for the Stockholm region [of Sweden]. In relation to this application an outline is given of the use of the methodology for long-term projections."

Patterns of family migration: two methodological approaches.

Abstract: It is widely recognized that many internal migrations are undertaken by individuals whose moves are dependent on those of others. For example, children migrate with their parents and wives with their husbands. This paper suggests two formulations of family migration that permit the introduction of such family dependencies into the population projection process.

LEG Risk Assessments: Experts Disagree

Abstract: One of the most challenging problems in decisions concerning the deployment of novel, large-scale technologies is the assessment of the risk to the surrounding populations. In particular cases, such as nuclear reactors or liquefied energy gas (LEG) facilities, the political process involved may tend to focus on one particular form of that risk: the risk to life from catastrophic accidents. This chapter examines several assessments of this type with two main goals in mind: (1) to present and compare the various risk assessment procedures as they have been applied to LEG terminal siting, and in so doing to clarify the limits of knowledge and understanding of LEG risks (2) to quantify and compare the risks estimated in analyses prepared for four LEG sites, namely: Wilhelmshaven (Brotz 1978; DGWE 1979; Krappinger 1978a,b,c; WSB 1978) Eemshaven (TNO 1978) Mossmorran—Braefoot Bay (Aberdour and Dalgety Bay Joint Action Group 1979, henceforth referred to as Aberdour; Cremer and Warner 1977; HSE 1978a) Point Conception (ADL 1978; FERC 1978; SAI 1976)

On the Geometry of Emergency Service Medical Provision in Cities

Abstract: The enormity of many cities today poses special problems for authorities supplying emergency medical services. The scale of the emergency system and variations in the operating conditions rule out some of the traditional methods developed to deal with the complexities involved. In cities the provision of services is affected not only by the daily varying locations of the populations at risk, but also by the prevailing traffic and weather conditions that can hinder ambulance access to the site of an incident or to a treatment facility. The controlling authorities of these services nevertheless like to maintain the highest possible levels of service given the available resources. They are interested in knowing which facilities to open and when, what resources and staffing levels are required, and what the long-term and short-term implications of changing operating conditions and of other unforeseen circumstances are on operating standards. In this paper the authors present research into a set of methods tha...

Input data uncertainty and parameter sensitivity in a lake hydrodynamic model

Abstract: Hydrodynamic models are often used to calculate the magnitude and direction of the wind-induced motion of water in lakes, in both engineering and water quality problems. The one- and two-dimensional model versions most frequently employed have two major parameters, the wind drag coefficient and the bottom friction coefficient. Although a number of important experiments have been performed in relation to the drag coefficient (for example Wu, 1969; Graf and Prost, 1980) and some information is also available to define a feasible range of values for the bottom friction, both parameters should be the subjects of model calibration as they are lumped in character.

Expert vs. Management Support Systems: Semantic Issues

Abstract: Expert systems hold great promise for technical application areas such as medical diagnosis or engineering design. They are, we argue, less promising for management applications. The reason is that managers are not experts in the sense of possessing a formal body of knowledge which they apply. The limitations of artificial intelligence approaches in managerial domains is explained in terms of semantic change, motivating attention toward management (decision( support systems.

Pasinetti, Marx and Urban Accumulation Dynamics

Abstract: Modeling change and accumulation in an urban system is a complex task that traditionally has been simplified by using a neoclassical model where a homogeneous good is produced from inputs of capital, labor, and technology (cf., Henderson, 1977). As ever, there is a price to be paid in this simplification; a price that is perhaps too high.

Age and Earnings in the Labour Market: Implications of the 1980s Labour Bulge

Abstract: Current theories offer conflicting guidance on how demographic changes in the labour force affect earnings and advancement over the working career. Human capital theory, as reflected in Welch (1978) for example, would predict that larger age cohorts than normal would earn less throughout their careers.1 If, as human-capital theory assumes, earnings are based on productivity, then the increased competition for complementary inputs must lower productivity and hence salaries. Members of larger labour cohorts will therefore have lower age-earnings profiles.

RTD 9(3) The Contribution of Oil and Gas for the Transition to Long Range Novel Energy Systems

Abstract: For medium and long range considerations of twenty to fifty years, i.e. up to the years 2000 and 2030, the growth of energy demand should be considered in a global context. Interdependence will grow. In the study `Energy in a Finite World' of the International Institute for Applied Systems Analysis (IIASA), Austria, demand and supply scenarios were elaborated in detail for seven world regions. One of the striking features of these scenarios is the strong and significantly increasing demand for liquid or gaseous hydrocarbons despite energy conservation and substitution measures. On the supply side this means more and more unconventional fossil fuels such as shale oil, tar sands and low-grade brown coal. In this paper we consider a transition from the current energy systems to novel fossil energy conversion and distribution systems that will contain all of the mass streams and thereby avoid environmentally hazardous emissions. It is then natural to extend these considerations to prospects for a sustainable hydrogen-based energy system in the far future which would not be constrained by resource limitations.

Energy Strategies and Nuclear Power

Abstract: The results of two quantitative scenarios balancing global energy supply with demand for the period 1980–2030 are reviewed briefly. The results suggest that during these 50 years there will be a persistent demand worldwide for liquid fuels, a continuing reliance on ever more expensive and “dirty” fossil fuels, and a limited penetration rate of nuclear generated electricity into the energy market. The paper therefore addresses a possible “second” grid driven by nuclear heat — a grid based not on electricity but on “clean” liquid fuels manufactured from gaseous and solid fossil fuels using nuclear power. Such a second grid would be an important complement to the electricity grid if the world is to progress towards a truly sustainable energy system after 2030.

Lagrangian Modeling of Air Pollutants Dispersion from a Point Source

Abstract: The ensemble average concentration due to an Instantaneous Point Source of an inert pollutant ( ) is given by the probability density of pollutant particle displacement G(x,t| x s,O), where x s is the source location and x is the particle location after a time t from the release.

Martingale approach to problem of sequential hypotheses testing

Abstract: This paper gives some new results in sequential hypotheses testing. The observable process should have continuous sampling paths. The minimum information criteria are reached with the fixed probabilities of wrong recognition.