Showing papers by "International Institute for Applied Systems Analysis published in 1992"
TL;DR: In this article, the potential impacts of CO2-induced climate change on terrestrial carbon storage were estimated using the Holdridge Life Zone Classification and four climate change scenarios derived from general circulation models.
Abstract: The potential impacts of CO2-induced climate change on terrestrial carbon storage was estimated using the Holdridge Life-Zone Classification and four climate change scenarios derived from general circulation models. Carbon values were assigned to life-zones and their associated soils from published studies. All four scenarios suggest an increase in area occupied by forests although details of predicted patterns vary among the scenarios. There is a poleward shift of the forested zones, with an increase in the areal extent of tropical forests and a shift of the boreal forest zone into the region currently occupied by tundra. Terrestrial carbon storage increased from 0.4% (8.5 Gt) to 9.5% (180.5 Gt) above estimates for present conditions. These changes represent a potential reduction of 4 to 85 ppm on elevated atmospheric CO2 levels.
152 citations
75 citations
TL;DR: In this paper, the optimal sensor location problem associated with minimax filtering for linear distributed parameter systems under the moving sensors is treated as an H ∞ -optimal control one under phase constraints with the objective to minimize a given weak performance index under the worst possible disturbances.
40 citations
TL;DR: The TRACE model as discussed by the authors is an improved climatological-type model in that travel time is computed from an empirical function rather than from an assumed constant velocity, the model tends to conserve mass, and the irregularity of spatial deposition patterns is captured, and parameters are objectively determined.
29 citations
TL;DR: In this paper, an ellipsoidal-valued solution for the problem of control synthesis is presented, which is based on the theory introduced by N.N. Krasovski and L.S. Pontriagin.
Abstract: This article is a continuation of the work reported in [4], introducing unknown but bounded disturbances into the problem of control synthesis studied there. The technique presented allows an algorithmization with an appropriate graphic simulation. The original theoretical solution scheme taken here comes from the theory introduced by N.N. Krasovski [1], from the notion of the “alternated integral” of L.S. Pontriagin [2] and the “funnel equation” in the form given in [3]. For alternative treatment of related problems, see also [5], [6], and [7]. The theory is used as a point of application of constructive schemes generated through ellipsoidal techniques developed by the authors. A concise exposition of the latter is the objective of this article. A particular feature is that the ellipsoidal techniques introduced here do indicate an exact approximation of the original solutions based on set-valued calculus by solutions formulated in terms of ellipsoidal-valued functions only.
24 citations
TL;DR: The necessary and sufficient conditions show that the capabilities of two-layered perceptrons extend beyond the exact classification of convex subsets, and an algorithmic approach is presented to the problem of verifying the sufficiency condition for a given subset.
Abstract: We study the capabilities of two-layered perceptrons for classifying exactly a given subset. Both necessary and sufficient conditions are derived for subsets to be exactly classifiable with two-layered perceptrons that use the hard-limiting response function. The necessary conditions can be viewed as generalizations of the linear-separability condition of one-layered perceptrons and confirm the conjecture that the capabilities of two-layered perceptrons are more limited than those of three-layered perceptrons. The sufficient conditions show that the capabilities of two-layered perceptrons extend beyond the exact classification of convex subsets. Furthermore, we present an algorithmic approach to the problem of verifying the sufficiency condition for a given subset.
13 citations
TL;DR: In this paper, the authors present a consistent energy scenario for Eastern European countries and compare optimal strategies to reduce SO 2 emissions based on runs with the RAINS model in which environmental targets have been set based on critical loads for sulphur.
13 citations
TL;DR: In this paper, a model of the U.S. automobile market is used to test the role that natural gas vehicles (NGVs) might play in reducing greenhouse-gas emissions.
Abstract: A model of the U.S. automobile market is used to test the role that natural gas vehicles (NGVs) might play in reducing greenhouse-gas emissions. Since natural gas (primarily methane) emits less CO2 per unit of energy than petroleum products, NGVs are an obvious pathway to lower CO2 emissions. High-and low-demand scenarios are used to forecast the emissions from unrestricted growth and a modest program of conservation, respectively. Based on these scenarios, a reference scenario is developed that projects a possible future path of automobile use and efficiency. It is found that without a dramatic increase in automobile use, fuel consumption and greenhouse-gas emissions from automobiles in the United States will probably decrease in the future, provided that efficiency continues to improve at modest rates. In theory, NGVs can help shift emissions even further down. A second objective is to quantify the role that leaking methane might play in offsetting some of the greenhouse advantages of NGVs. To do this, a simple atmospheric chemistry model is applied to the reference scenario; several leak rates and feedback factors are used to test the sensitivity of the projected green-house forcing from now until 2050. Committed warming beyond 2050 is not included, and the results should be interpreted with that in mind. It is highly unlikely that switching automobiles from gasoline to natural gas will appreciably lower future greenhouse forcing. Constraints on vehicle miles travelled as well as continued improvements in vehicle efficiency will make a much larger contribution towards controlling global warming.
10 citations
TL;DR: The ways to minimize the difficulties due to population and its growth to be found in current literature have been grouped under seven heads in a far from exhaustive listing.
Abstract: The ways to minimize the difficulties due to population and its growth to be found in current literature have been grouped under seven heads in a far from exhaustive listing:
8 citations
TL;DR: This paper gives a concise description of effective solutions to the "guaranteed" state estimation problems for dynamic systems with unknown but bounded uncertainty based on the notion of evolution equations of the "funnel" type which could be further transformed through exact ellipsoidal approximation - into algorithmic procedures that allow effective simulation particularly with computer graphics.
8 citations
TL;DR: The IIASA research project on Environmentally Compatible Energy Strategies includes the assessment of options and measures for mitigating global CO2 emissions as mentioned in this paper, which includes efficiency improvement, conservation, enhanced use of low-carbon fuels, carbon free sources of energy and measures to remove carbon from fuels, flue gases and also from the atmosphere such as afforestation, and finally also measures for enhancement of carbon sinks.
TL;DR: Alternative multi-state population projections to 2050 based on six scenarios show that in the case of no further immigration the total population of Western Europe will start to decline after 2010 and the rate of integration influences the future size of the non-European population much more than alternative levels of immigration.
Abstract: The population of Western Europe (EC plus EFTA) is seen as consisting of three sub-populations: the natives, the East-European immigrants, and the non-European immigrants. Different immigration levels assumed add to the non-native populations while different levels of “integration” describe the transition intensities from a non-native to a native category. Alternative multi-state population projections to 2050 based on six scenarios show that (1) in the case of no further immigration the total population of Western Europe will start to decline after 2010; (2) the rate of integration influences the future size of the non-European population much more than alternative levels of immigration; (3) in the long run the Eastern Europeans will be quantitatively insignificant; (4) the Western European population is bound to significant population aging no matter what happens with immigration; and (5) in the short to medium run immigrants contribute to the alleviation of the pension burden.
TL;DR: In this article, the purpose and methods of emission inventories and compares the major international inventories in Europe are reviewed and compared for S02, N0X, and ammonia emissions.
Abstract: Emissions of S02, N0X and ammonia are major contributors to acidification of natural ecosystems. The paper reviews purpose and methods of emission inventories and compares the major international inventories in Europe. For each of the pollutants the major gaps in current knowledge and discrepancies in existing data are briefly discussed. Finally, national differences in per-capita emissions are analyzed for the year 1985.
TL;DR: Analyse du mode de fonctionnement de l'industrie energetique europeenne, consideree comme un monopole regional du service public, is presented in this article.
Abstract: Analyse du mode de fonctionnement de l'industrie energetique europeenne, consideree comme un monopole regional du service public. Presentation des theories de la dereglementation et de la reglementation alternative, a la lumiere des experiences americaine et anglaise. Analyse des possibilites de dereglementation de l'industrie europeene, notamment electrique.
01 Jan 1992
TL;DR: In this article, the perturbation techniques for dynamic systems described by differential inclusions and state constraint relations are discussed, where the phase restrictions are replaced by a new differential inclusion with a small parameter multiplying the derivative.
Abstract: The paper deals with the perturbation techniques for dynamic systems described by differential inclusions and state constraint relations. We replace the phase restrictions by a new differential inclusion with a small parameter multiplying the derivative and study the limit behaviour of the system combining two groups of differential inclusions, the former to be the given differential inclusion and the latter to be the introduced one. The idea based upon consideration of all matrix time-varying perturbations to this system allows one to describe the attainability sets of the primary differential inclusion under state constraints. Applications to the control and observation problems are also discussed.
01 Jan 1992
TL;DR: Al Alcamo et al. as mentioned in this paper developed the TRACE model to compute the long range transport of various heavy metals (As, Cd, Pb, and Zn) on the European-scale.
Abstract: There is increasing observational evidence that heavy metals’ air emissions cause not only local contamination, but also travel long distances in Europe and contribute to widespread, although low-level, contamination of the environment (e.g. Pacyna, et al, 1984; Ottar, et al, 1989). The TRACE model (TRB.cetoxic Air Concentrations in fftirope) has been developed to compute the long range transport of various heavy metals (As, Cd, Pb, and Zn) on the European-scale. A preliminary version of this model was reported in Alcamo, et al (1991a) and model refinements and application are given in Alcamo, et al (1991b) and Bartnicki et al (1991).
01 Jan 1992
TL;DR: In this paper, a conceptual model is developed to portray the linkages between poverty, affluence and environmental change which in turn can affect human development, and these conceptual models can then be "operationalized" into scientifically-based models to examine specific environment/development linkages by means of case studies.
Abstract: Conceptual models can be developed to portray the linkages between poverty, affluence and environmental change which in turn can affect human development. These conceptual models can then be "operationalized" into scientifically-based models to examine specific environment/development linkages by means of case studies. An example is given of the linkage between emissions from fossil fuel emissions in Europe and the degradation of forest resources.