Showing papers by "International Institute for Applied Systems Analysis published in 1990"
TL;DR: In this paper, the evolution of reactive strategies for repeated 2×2 games occurring in biology is investigated by means of an adaptive dynamics, and an adaptive dynamic model is proposed to describe the dynamics of repeated 2x2 games.
Abstract: The evolution of reactive strategies for repeated 2×2-games occurring in biology is investigated by means of an adaptive dynamics
290 citations
TL;DR: A dynamics for frequency dependent selection is proposed and applied to several biological examples and the relation with game dynamics and evolutionary stability is analyzed.
203 citations
TL;DR: In this article, a set-valued Gronwall lemma and a relaxation theorem for the semilinear differential inclusion problem with end-point constraints were proved and applied to a semi-linear optimal control problem with variational inclusions.
106 citations
TL;DR: This case study will provide valuable insights on the conditions of exit from a “lock-in” situation and the MA will permit us to avoid misinterpretation concerning the asymmetrical character and discontinuities of the diffusion trajectory of the technology under consideration.
53 citations
TL;DR: In this paper, the authors analyzed costs and relative benefits of several hundred flexible manufacturing systems (FMSs) in the world and showed that the main benefits are increased capacity and productivity as well as quality improvements.
Abstract: This article analyzes costs and relative benefits of several hundred flexible manufacturing systems (FMSs) in the world. The analyses are based on the computerized data bases, which make it easy to correlate different cost and benefit indicators with each other and to look for regular patterns and tendencies in the applications. Both investment cost distributions and the system complexity distributions are analyzed. The relative benefits and advantages and their relationships are shown. Finally, technical and economic explanations for successful implementation strategies are given. The results show that there are two classes of economically successful systems. The small-scale and technically compact systems are usually used in small-batch production for the replacement of semimanual production. The main benefits are increased capacity and productivity as well as quality improvements. The large-scale and technically complex systems are used in large-volume production for the replacement of fixed automation and transfer lines. The benefits are mainly due to the increased potential for flexibility and capital savings.
50 citations
01 Jan 1990
TL;DR: The use of model-based information and DSS, and in particular of interactive simulation and optimization models that combine traditional modelling approaches with new expert systems techniques of Artificial Intelligence (AI), dynamic computer graphics and geographical information systems, is demonstrated in this chapter.
Abstract: Geographical Information Systems (GIS) are gaining increasing importance and widespread acceptance as tools for decision support in land, infrastructure, resources, environmental management and spatial analysis, and in urban and regional development planning. GIS assist in the preparation, analysis, display, and management of geographical data. It is in the analysis and display functions that GIS meet Decision Support Systems (DSS). DSS analyse and support decisions through the formal analysis of alternative options, their attributes vis-a-vis evaluation criteria, goals or objectives, and constraints. DSS functions range from information retrieval and display, filtering and pattern recognition, extrapolation, inference and logical comparison, to complex modelling. The use of model-based information and DSS, and in particular of interactive simulation and optimization models that combine traditional modelling approaches with new expert systems techniques of Artificial Intelligence (AI), dynamic computer graphics and geographical information systems, is demonstrated in this chapter with application examples from technological risk assessment, environmental impact analysis, and regional development planning. With the emphasis on an easy-to-understand visual problem representation, using largely symbolic interaction and dynamic images that support understanding and insight, these systems are designed to provide a rich and directly accessible information basis for decision support and planning.
47 citations
TL;DR: It is shown that an invasion of a small number of pests into a steady-state forest ecosystem could result in intensive oscillations of its age structure.
44 citations
TL;DR: In this article, throughfall fluxes in European forests are analyzed and compared to deposition to bulk collectors located in nearby open land, to get an idea of the filtering efficiency of forests.
Abstract: The assessment of atmospheric sulfur deposition to forest is difficult because of its complex aerodynamic structure. Therefore, atmospheric deposition of sulfur to forest is often estimated by means of measuring throughfall fluxes onto the forest floor. In this paper, reported measurements of throughfall fluxes in European forests are analyzed. These fluxes are compared to deposition to bulk collectors located in nearby open land, to get an idea of the filtering efficiency of forests. In addition, fluxes are compared with deposition estimates from a long-range transport model of air pollutants, linked to an emission generation model. According to reported measurements from 52 European conifer stands, we found that the sulfur flux was 3.8 ± 2.3 times greater onto the forest floor than onto precipitation collectors. In a similar data set of 13 deciduous stands this ratio was 2.3 ± 0.9. The ratio of throughfall flux to model estimate was 1.8 ± 0.9 in coniferous stands and 0.9 ± 0.3 in deciduous stands. For sites that are located in moderately to highly sulfur polluted areas, it is assumed that throughfall fluxes give a good estimation of the atmospheric sulfur deposition. We conclude that (1) sulfur deposition to forests is 1.5 to 6 times higher than deposition to smooth receptor surfaces due to an efficient filtering by the forest canopy, (2) average annual sulfur deposition at a given location is 50–100% greater on conifers than on deciduous trees, (3) the existing European scale model that links sulfur deposition to the pollution generation processes is quite accurate as far as deciduous forests are concerned, and (4) the model underestimates deposition to coniferous forests. DOI: 10.1034/j.1600-0889.1990.t01-2-00008.x
27 citations
TL;DR: In this paper, the authors investigated the composite uncertainty of a long range transport model of sulfur in Europe, including the effect on model output of uncertain transport wind, meteorological forcing functions, parameters, and spatial distribution of emissions.
24 citations
TL;DR: In this article, a simple model of the world air market is used to test the role that liquid hydrogen (LH2) aircraft might play in reducing carbon dioxide (CO2) emissions from this sector of the economy.
16 citations
19 Sep 1990
TL;DR: The volume and complexity of this information, uncertainty in the data and the understanding of processes, as well as the often very large number of alternatives to be considered require specific data processing tools.
Abstract: Environmental planning and management require comprehensive and interdisciplinary information as the scientific and technical information basis for what are, ultimately, political decisions. The volume and complexity of this information, uncertainty in the data and the understanding of processes, as well as the often very large number of alternatives to be considered require specific data processing tools.
TL;DR: In this paper, the authors summarize the existing evidence on the actual impacts of FMS on inventories, reveal the relations between inventory reduction and the technical and operational features, and put forward some hypothesis about the impact of implementation strategies on inventory reduction.
TL;DR: In this paper, the authors argue that informational-scale economies can only be achieved if information technologies in production per se is truly integrated with their use in other management functions, instead of being introduced ad hoc as is being done in most firms at present.
TL;DR: In this article, the authors explored the need for a comprehensive emissions accounting system for environmentally harmful chemicals and suggested a classification scheme that identifies environmental emissions at particular stages in the life cycle of chemicals as they flow through the industrial economy.
TL;DR: An attempt has been made to integrate the two approaches to spatial planning by developing a hybrid multicriteria alternative selectiion module (HYDAS-HYbrid Discrete Alternative Selection) which will work as a postprocessor for both modules.
Abstract: During the development of an expert system for regional planning (The Shanxi Province Decision Support System) by IIASA's Advanced Computer Applications (ACA) group, two spatial planning systems evolved. PDAS, a system for the optimization of the industrial structure of an area, which is based on numerical multicriteria optimization techniques; and REPLACE, a site-selection system, implemented in PROLOG, which is based on a qualitative, constraint-satisfaction method. Although both approaches partially overlap, each approach has certain advantages over the other. As a natural extension of the Shanxi DSS, within the framework of a project on Hybrid Decision Support Tools sponsored by the U.S. Bureau of Reclamation, an attempt has been made to integrate the two approaches by developing a hybrid multicriteria alternative selectiion module (HYDAS-HYbrid Discrete Alternative Selection) which will work as a postprocessor for both modules. In HYDAS, artificial intelligence (AI) paradigms and numeric multicriteria optimization techniques are combined to arrive at a hybrid approach to discrete alternative selection. These techniques include: (1) qualitative analysis, (2) various statistical checks and recommendations, (3) robustness and sensitivity analysis, and (4) help for defining acceptable regions for analysis. HYDAS is implemented on high performance workstations using C, PROLOG, and the X graphics library and window system.
TL;DR: In this article, potential future emissions of nitrogen oxides for the hypothetical case of no control measures being applied and the effects of the reduction commitments made in the 'Sofia Protocol' and the 'Declaration on a 30% cut' of NOx emissions in Europe are analyzed.
TL;DR: An old but difficult topic, viz. how to find more and more solutions of a system of nonlinear equations, is addressed by using so-called locally affective functions to transform the original system to a new system, which has not the already found solutions, but only the unfound solutions.
TL;DR: In this paper, the authors introduce three estimation problems for parabolic systems: the estimation of the intensity of sources on the basis of available measurements, the state of a distributed process through given observations, and an inverse problem of multiobjective optimization whose solution allows to estimate the largest input levels that ensure a guaranteed system output performance.
TL;DR: The use of models, and in particular, of interactive simulation and optimization models that combine traditional modeling approaches with new techniques of Artificial Intelligence (AI) and dynamic computer graphics, is demonstrated by a number of application examples in air, surface and ground water modeling as well as environmental risk analysis.
TL;DR: A technique for identifying the cohorts that initiated what in the 1950s was designated the population explosion is developed, which gives very nearly the same increase whatever age is used for the estimate.
Abstract: For tracing the growth of populations over past time a useful indicator is cohort size. While a cohort moves through time, and therefore cannot be counted in the same way as the population of any given moment, yet its size can be measured as births less deaths up to some intermediate age. This may be estimated from a series of censuses, without reference to vital statistics or other data. The technique is applied to the onset of the world wide population expansion that followed World War II. In several Asian countries it took place in a single five‐year period with a multiplication of earlier intercohort increases by as much as threefold. The jump occurred early in Burma, late in Indonesia, and suddenly in both of those countries; in India it was more gradual, so that the onset of the current population expansion is less sharply marked. Calculation also shows a corresponding discontinuity in the rate of population change after World War I in a number of countries, but of lesser magnitude. Insofar as one m...
TL;DR: This paper deals with new variable metric algorithms for nonsmooth optimization problems, so-called “adaptive algorithms”, where there are two simultaneously working gradient algorithms, the first in the main space, the second with respect to the matrices that modify the space variables.
Abstract: This paper deals with new variable metric algorithms for nonsmooth optimization problems, so-called “adaptive algorithms”. The essence of these are as follows: there are two simultaneously working gradient algorithms, the first in the main space, the second with respect to the matrices that modify the space variables. The convergence theorems for these algorithms are given for different cases.
TL;DR: The analyses are based on the computerized databases, which make it easy to correlate different cost and benefit indicators with each other and to look for regular patterns and tendencies in the applications, and show that there are two classes of economically successful systems.
TL;DR: A number of sufficient conditions are obtained for the observation to have the information structure such that the information in the quadratic covariation process is not contained in the additive Gaussian part of the observation and/or the Brownian motion parts of the innovation process.
Abstract: This paper is concerned with information structure of the observation with additive non-Gaussian noise under the assumption that the noise belongs to a class of continuous martingales. It is known that such an observation is decomposed into a process with additive Gaussian noise and the quadratic covariation process of the additive noise. It is also known that the innovations process is decomposed into a standard Brownian motion process and the quadratic covariation process. In this paper, a number of sufficient conditions are obtained for the observation to have the information structure such that the information in the quadratic covariation process is not contained in the additive Gaussian part of the observation and/or the Brownian motion part of the innovation process.
01 Jan 1990
TL;DR: In this article, the authors explore the direct method where the model equations are used to solve for the endogenous variables, which are then eliminated from the criterion functions, resulting in an optimization problem involving only the control variables.
Abstract: There are different approaches to optimize a deterministic dynamic economic system, expressed in structural or reduced form. In this paper we explore the direct method where the model equations are used to solve for the endogenous variables, which are then eliminated from the criterion functions, resulting in an optimization problem involving only the control variables. This problem is mostly of much lower dimension than the original one, and it is shown how the gradients of the criterion function can be easily calculated. For the linear-quadratic case we show how the optimality conditions can be expressed so that the matrix Riccati equation results; for this problem approaches are therefore equivalent. However, the direct gradient approach is of considerable more generality, allowing for instance nonlinear model equations which may include stochastic coefficients and/or general nonsmooth criterion functions. In this paper we explore these more general situations. Quadratic and minimax type objective functions are used and the usefulness of the approach is discussed.
19 Sep 1990
TL;DR: Das RAINS Modell kombiniert Informationen uber die einzelnen Phasen der Entstehung and Wirkungsweise saurer Niederschlage in Europa werden fur alle 27 Staaten West- und Osteuropas SO2, N0X and NH3 Emissionen berechnet.
Abstract: Das RAINS Modell kombiniert Informationen uber die einzelnen Phasen der Entstehung und Wirkungsweise saurer Niederschlage in Europa. Ausgehend von umfassenden Energiestatistiken werden fur alle 27 Staaten West- und Osteuropas SO2, N0X und NH3 Emissionen berechnet. Anschliesend werden Schadenswirkungen auf Suswasserseen, Waldboden und Forst bestande simuliert. Ein Optimierungsalgorithmus erlaubt die international kostenoptimale Allokation von Emissionsminderungsmasnahmen zur Erreichung vorgegebener Depositionsgrenzwerte. Das RAINS Modell wird derzeit sowohl von nationalen Institutionen, als auch im Rahmen internationaler Verhandlungen uber Emissionsminderungsmasnahmen eingesetzt.