Showing papers by "International Institute for Applied Systems Analysis published in 1991"
TL;DR: In this article, the authors review different views of Neo-classical and ecological economics on the sustainability of economic growth and welfare, concluding that, due to substitution and technical progress, consumption can be sustained even if production depends on a natural resource that is being depleted.
148 citations
TL;DR: The characteristic S-shaped diffusion pattern and the resulting rates of diffusion are a macroaggregate of an underlying complexity of adoption causes, and diffusion phenomena are probably best conceptualized as proceeding through various stages of a diffusion life cycle.
99 citations
TL;DR: In this article, the authors analyzed the different regional and generational contributions to increases of CO2 concentrations resulting from fossil fuel use since the onset of the industrial revolution and proposed an intra-and inter-generational equity criterion for each human being to be allowed an equal emission right per year, independent of time or place lived.
58 citations
TL;DR: A workshop on CO2 reduction and removal measures for the next century was held at the International Institute for Applied Systems Analysis (IIASA) as mentioned in this paper, where 48 participants represented more than 11 disciplines from academic, private and public organizations from 15 different countries both North and South.
53 citations
TL;DR: It is concluded that PRA is a valuable tool for auditing safety precautions of existing or planned technologies, especially when it is carried out as an interactive process involving designers and plant personnel who are familiar with actual, everyday operations.
Abstract: Probabilistic risk assessment (PRA) is an important methodology for assessing the risks of complex technologies. This paper discusses the strengths and weaknesses of PRA. Its application is explored in three different settings: adversarial policy processes, regulatory/licensing procedures, and plant safety audits. It is concluded that PRA is a valuable tool for auditing safety precautions of existing or planned technologies, especially when it is carried out as an interactive process involving designers and plant personnel who are familiar with actual, everyday operations. PRA has not proven to be as well-suited in providing absolute risk estimates in public-policy debates concerning the acceptability of a technology, or for the licensing and regulatory procedures. The reasons for this are discussed.
46 citations
TL;DR: This paper deals with new variable-metric algorithms for nonsmooth optimization problems, the so-called adaptive algorithms, that there are two simultaneously working gradient algorithms in the space of the matrices that modify the main variables.
Abstract: This paper deals with new variable-metric algorithms for nonsmooth optimization problems, the so-called adaptive algorithms. The essence of these algorithms is that there are two simultaneously working gradient algorithms: the first is in the main space and the second is in the space of the matrices that modify the main variables. The convergence of these algorithms is proved for different cases. The results of numerical experiments are also given.
33 citations
01 Jan 1991
TL;DR: In this article, it is shown that for one partitioning of the state space an explicit ergodicity condition can be derived from Neuts' mean drift condition, whereas for another partitioning the associated R-matrix can be determined explicitly, both partitionings used are different from the one suggested by the conventional way of applying the matrix-geometric approach.
Abstract: In this paper we study a system consisting of c parallel servers with possibly different service rates. Jobs arrive according to a Poisson stream and generate an exponentially distributed workload. An arriving job joins the shortest queue, where in case of multiple shortest queues, one of these queues is selected according to some arbitrary probability distribution. If the maximal difference between the lengths of the c queues exceeds some threshold value T, then one job switches from the longest to the shortest queue, where in case of multiple longest queues, the queue loosing a job is selected according to some arbitrary probability distribution. It is shown that the matrix-geometric approach is very well suited to find the equilibrium probabilities of the queue lengths. The interesting point is that for one partitioning of the state space an explicit ergodicity condition can be derived from Neuts' mean drift condition, whereas for another partitioning the associated R-matrix can be determined explicitly. Moreover, both partitionings used are different from the one suggested by the conventional way of applying the matrix-geometric approach. Therefore, the paper can be seen as a plea for giving more attention to the question of the selection of a partitioning in the matrix-geometric approach. Key Words: jockeying, matrix-geometric solution, queues in parallel, shortest queue.
28 citations
TL;DR: In this article, the authors argue that the whole matter of projecting mortality comes down to deciding what past period describes the future and conclude that any of several methods could be used including the Brass method but that no trend calculation or regression on economic variables seems able to forecast the future that is to [accurately account for such events as] technical advance...and new fashions in behaviour."
Abstract: How fast will mortality fall in the decades ahead? One way of phrasing the question is in terms of past periods: will it be as fast as Canada showed in 1976-81 or only as fast as the average 1921-81 or as slow as 1926-31?...I will argue that the whole matter of projecting mortality comes down to deciding what past period describes the future.... The author concludes that any of several methods could be used including the Brass method but that "no trend calculation or regression on economic variables seems able to forecast the future that is to [accurately account for such events as] technical advance...and new fashions in behaviour." Life tables for Canada concerning the period 1920-1982 are used as illustrations. (SUMMARY IN FRE) (EXCERPT)
25 citations
TL;DR: In this article, the authors demonstrate that the diffusion of pervasive systems worldwide tends to cluster toward the saturation period and that the time span between the start of diffusion in leading and lagging countries decreases as the diffusion progresses.
20 citations
TL;DR: This article gives an early account of the application of ellipsoidal techniques to various problems in modeling dynamical systems and concentrates on constructive solutions generated through ellip soidal-valued calculus and related approximation techniques for set-valued maps.
Abstract: This article gives an early account of the application of ellipsoidal techniques to various problems in modeling dynamical systems. The problem of control synthesis for a linear system under bounded controls was selected as the first simple application of these techniques. In forthcoming papers, these results will be extended to the case where unknown but bounded disturbances are present. Guaranteed state estimation—also to be interpreted as a tracking problem—again under unknown but bounded disturbances will also be discussed.
18 citations
TL;DR: In this paper, the authors evaluated the uncertainty of targeted emission control strategies aimed at the cost-effective control of sulfur deposition in Europe using two procedures: one accounts for parameter and data errors using a chance-constraint procedure.
TL;DR: The main objective is to show that the longitudinal path can be designed to maintain the positive definiteness of the reduced matrices by means of the positivity ofγkTδk, whereγk is the change in the reduced gradient and δ k is the reduced longitudinal displacement.
Abstract: We propose an algorithm for minimizing a functionf on ℝn in the presence ofm equality constraintsc that locally is a reduced secant method. The local method is globalized using a nondifferentiable augmented Lagrangian whose decrease is obtained by both a longitudinal search that decreases mainlyf and a transversal search that decreases mainly ∥c∥. Our main objective is to show that the longitudinal path can be designed to maintain the positive definiteness of the reduced matrices by means of the positivity ofγkTδk, whereγk is the change in the reduced gradient and δk is the reduced longitudinal displacement.
01 Jan 1991
TL;DR: The long range transport of heavy metal in the atmosphere leads to low but steady deposition of heavy metals into soils, lakes and forests in Europe as mentioned in this paper, which can lead to disturbance of organic matter decomposition and nutrient cycling.
Abstract: The long range transport of heavy metals in the atmosphere leads to low but steady deposition of heavy metals into soils, lakes and forests in Europe. Although their atmospheric fluxes are low, these metals can accumulate in the detritus of soils. This accumulated metal may be mobilized by acidification and may then disturb soil organisms, which in turn can lead to disturbance of organic matter decomposition and nutrient cycling (Ottar et al., 1989). Circumstantial evidence from wind sector analysis and trajectory modeling (Pacyna et al., 1984), and receptor modeling (Stevens et al., 1984) indicates that the deposition of metals may originate from sources many hundreds of kilometers away. It is thought that large particles (> 10 μ) settle out in the vicinity of the stacks but stack gases containing metals condense into small particles which then coalesce within hours into particles with diameters of 0.1 to 1.0 μ; particles of this size are too coarse to be efficiently removed by brownian diffusion yet too small to settle out by gravity. Hence these metal particles may travel long distances before being removed by precipitation or dry deposition.
01 Jan 1991
TL;DR: In this article, the authors discuss three key concepts that are discussed in detail, using a number of operational software examples: integration, interaction and visualization, in order to design and implement smart software where the emphasis is on the man-machine interface.
Abstract: Water resources planning and management has a considerable history in the use of computers. By covering a problem domain that combines a solid foundation in the physical sciences, and a large amount of data, with strong elements of socio-economic and political considerations, water resources planning and management is also an ideal application area for the latest advanced information technology. Advanced information technology provides the tools to design and implement smart software where, in a broad sense, the emphasis is on the man-machine interface. Integration, interaction and visualization are three key concepts that are discussed in detail, using a number of operational software examples.
TL;DR: In this paper, a set of existing optimization models, which represent the energy systems of the OECD and LDCs with a time horizon to 2020, has been applied to derive first-order estimates of the technoeconomic potential for emission reduction.
TL;DR: The U.S. is the largest energy producer and the second largest energy consumer in the world as discussed by the authors, and its share of global energy use reached above 17% in 1988, although there are some reasons justifying the greater energy use per unit of product output than in other industrialized countries.
TL;DR: The tenth annual meeting of the International Energy Workshop (IEW) was held IIASA as discussed by the authors, which included sessions on the forthcoming establishment of the common energy market in the European Community, the prospects for the development of the energy system in the economies of the former Soviet Union and Eastern Europe, and the global environment.
Abstract: The tenth annual meeting of the International Energy Workshop (IEW) was held IIASA. In addition to analyses of the IEW survey of expected crude oil prices, economic growth, primary energy consumption and production, and energy trade, this meeting featured sessions on the forthcoming establishment of the common energy market in the European Community, the prospects for the development of the energy system in the economies of the former Soviet Union and Eastern Europe, and the global environment.
This report is divided into three sections. The first section presents and analyzes the latest poll results. The next section reports on the papers presented at the IEW meeting. The final section briefly summarizes the proceedings of the special session held at the meeting.
TL;DR: In this paper, the authors examined a combination of technologies and circumstances that make large scale water splitting using nuclear heat from HTR reactors an attractive proposition, and showed that the broad scale evolution of the system will open a "window of opportunity" for this project during the next 10 years.
01 Jan 1991
TL;DR: In this paper, the equilibrium distribution of a Markov process with states (m, n) is analyzed in the context of a continuous-time Markov queueing system, where m and n denote the number of jobs at the CP and the 10 unit respectively.
Abstract: In this paper we study a multiprogramming system consisting of an input-output unit (10 unit) and a central processor (CP). This system can be represented by a continuous time Marlmv process with states (m,n). where m and n denote the number of jobs at the CP and the 10 unit respectively. The computation of the equilibrium distribution {p_{m,n}} of this Markov process is the purpose of the analysis in this paper. The analysis consists of two parts. In the first part, we use a compensation procedure to show that the equilibrium distribution {p_{m,n}} in those states (m,n) for which m+n is not too small, can be expressed as an infinite linear combination of product forms. Explicit formulae are given for the product forms and the coefficients of this infinite linear combination. In the second part of the analysis, we pay attention to some numerical aspects of the computation of the equilibrium distribution. For the computation of the equilibrium probabilities that can be expressed as infinite linear combinations of product forms, we derive bounds for the errors caused by cutting off these infinite linear combinations, and after that we present numerically stable formulae to compute one by one the remaining equilibrium probabilities. Keywords: multiprogramming queues problem, Markov process, equilibrium distribution, product form, convergence of series, embedded Markov process, bounds.
01 Jan 1991
TL;DR: In this paper, the authors proposed a Lagrangian-based model for the long-range transport of heavy metals into the North Sea and the Baltic, which is based on trajectory computations.
Abstract: The modeling activity on the long range transport of air pollutants has been mainly focused on sulfur and nitrogen oxides for the past several years. Compared to sulfur and nitrogen, much less development can be noticed in modeling long range transport of heavy metals. The existing models were designed either for computing transport of heavy metals into the Baltic and the North Sea (Grasl et al., 1989; Krell and Roeckner, 1988; Jaarsveld et al., 1986), or to the Arctic (Pacyna and Ottar, 1985; Pacyna et al., 1985, 1989). Except Jaarsveld’s climatologic approach and the stochastic model of Krell and Roeckner, the above models are of Lagrangian type based on the trajectory computations. Another climatologic model (Alcamo et al., 1990) was designed to compute long range transport of heavy metals in Europe but because of the resolution of the climatologie data, there might be some difficulties to run it for the transport period shorter than one year.
01 Dec 1991
TL;DR: In this article, the authors used the OECD INTERLINK model to assess the macroeconomic impacts of a European Community directive to control air pollution and found that the impacts are small and are positive during the investment period and more negative in the subsequent period.
01 Jan 1991
TL;DR: Environmental planning and management, especially environmental impact assessment, is a task of global importance that requires comprehensive, interdisciplinary Information.
Abstract: With steady population growth and industrialization, human activities have increasingly affected the environment Growing concern about these impacts and their immediate, as well as longterm consequences, including risk associated with technological systems and the inherent uncertainty of any forecast makes environmental planning and management, especially environmental impact assessment, a task of global importance that requires comprehensive, interdisciplinary Information
TL;DR: The main hypothesis of the investigation is that dispersion processes interact in such a way that in the zone of influence of one process (near its mode) the ‘tails’ of the other process are not observed, which permits illumination of interrelations between the physics and the chemistry of the atmosphere.
Abstract: This paper describes an approach for identifying statistically stable central tendencies in the frequency distributions of time series of observations of background atmospheric pollutants. The data were collected as daily mean values of concentrations of sulfur dioxide and suspended particulate matter at five monitoring stations—three in the USSR, one in Norway, and one in Sweden. The approach uses statistical techniques and methods for constructing multimodal distributions. The problem is subdivided into two parts: first, a decomposition of the observations in order to obtain a description of each season separately and second, an investigation of this description in order to derive statistically stable characteristics of the entire data set. The main hypothesis of the investigation is that dispersion processes interact in such a way that in the zone of influence of one process (near its mode) the ‘tails’ of the other process are not observed. This permits illumination of interrelations between the physics and the chemistry of the atmosphere.
TL;DR: The last section of the paper is focused on application of the program in the study on operation of multiple reservoir system of the Zambezi river in southern Africa.
01 Oct 1991
TL;DR: Most of the example-based learning algorithms developed so far are limited by the fact that they learn unidirectionally, i.e., they just transform the presented examples into a fixed internal representation form and do not adapt their learning strategy according to the results of this transformation process.
Abstract: Most of the example-based learning algorithms developed so far are limited by the fact that they learn unidirectionally, i.e., they just transform the presented examples into a fixed internal representation form and do not adapt their learning strategy according to the results of this transformation process. Only a few learning algorithms incorporate such a feedback from an evaluation of the learned problem representation to the input for the next learning step. But all those rely on quantitative evaluation of the problem representation only, qualitative criteria are always neglected.
01 Jan 1991
TL;DR: The Chernobyl nuclear reactor breached containment and released more than 100 million curies of radioactivity into the environment The release from this worst case accident, which has been compared to several dozen Hiroshima bombs (Hohenemser and Renn, 1988), conformed little, if at all, to accepted nuclear accident scenarios as discussed by the authors.
Abstract: In April 1986, the Chernobyl nuclear reactor breached containment and released more than 100 million curies of radioactivity into the environment The release from this worst case accident, which has been compared to several dozen Hiroshima bombs (Hohenemser and Renn, 1988), conformed little, if at all, to accepted nuclear accident scenarios To everybody’s relief, there were far fewer immediate fatalities in the Ukraine than would have been anticipated Actual deaths, however, instead became anonymous statistical deaths The radionuclide contamination reached most of the Northern Hemisphere, and expected future cancer fatalities may be in the thousands[1]
01 Jan 1991
TL;DR: In this paper, the selection of an initial distribution in the first boundary-value problem for the heat equation in a given domain [0,θ]×Ωθ 0.
Abstract: This paper deals with the selection of an initial distribution in the first boundary-value problem for the heat equation in a given domain [0,θ]×Ωθ 0. The result is formulated here in terms of the “theory of guaranteed estimation” for noninvertible evolutionary systems. It also allows an interpretation in terms of regularization methods for ill-posed inverse problems and in particular, in terms of the quasiinvertibility techniques of J.-L. Lions and R. Lattes.
01 Jan 1991
TL;DR: In this article, a series of problems on state estimation for parabolic systems on the basis of measurements generated by sensors in the presence of unknown but bounded disturbances are introduced, and guaranteed filtering schemes for distributed processes are discussed.
Abstract: This paper introduces a series of problems on state estimation for parabolic systems on the basis of measurements generated by sensors in the presence of unknown but bounded disturbances. Observability issues, guaranteed filtering schemes for distributed processes are discussed.
TL;DR: In this paper, a parabolic parameterization of the long-term tendency of the CO 2 field as a function of time is proposed, based on the technique of supervised training.
Abstract: A new methodological approach for the analysis of monitoring data is discussed. The main ideas are illustrated for the example of the CO 2 problem. The analysis of CO 2 concentrations obtained from a global network of monitoring stations permitted us to construct a nonparametric evaluation of the spatial-temporal distribution of this field. We propose a parabolic parameterization of the long-term tendency of this field as a function of time (in one-year time steps). A function of the predictive ability of a model is defined on the basis of the technique of “supervised training.” This function is computed for a parabolic model and it is shown that this model constructed for the first 15 years of observations evaluates the tendency for the next 15 years quite well. The main problem that we solve in this paper is how to correlate the projections of different models for the carbon cycle and different scenarios of the annual release of carbon into the atmosphere with the projections that reflect parameterization of the trends of CO 2 -monitoring data. DOI: 10.1034/j.1600-0889.1991.00011.x