Showing papers by "International Institute for Applied Systems Analysis published in 1987"

Repeated resuscitation: how lifesaving alters life tables.

Abstract: How does saving lives affect the force of mortality and life table statistics? How can the progress being made in reducing the force of mortality be interpreted in terms of lifesaving? How many times can a person expect to have his or her life saved as a result of this progress? We develop a model to answer these questions and illustrate the results by using mortality rates for the United States in 1900 and 1980 and as projected for 2050.

Scale relationships in the interactions of climate, ecosystems, and societies

Abstract: Climates, ecosystems, and societies interact over a tremendous range of temporal and spatial scales. Scholarly work on forecasting climate impacts has tended to emphasize different questions, variables, and modes of explanation depending on the primary scale of interest. Much of the current debate on cause and effect, vulnerability, marginality, and the like stems from uncritical or unconscious efforts to transfer experience, conclusions, and in-sights across scales. This paper sketches a perspective from which the relative temporal and spatial dimensions of climatic, ecological, and social processes can be more clearly perceived, and their potential interactions more critically evaluated. Quantitative estimates of a variety of characteristic scales are derived and compared, leading to specific recommendations for the design of climate impact studies.

Age-specific mortality trends in France and Italy since 1900: Period and cohort effects

Abstract: Although France and Italy currently exhibit very similar expectations of life, their mortality patterns by age and sex are not the same. The differences were much greater at the beginning of the century than they are now. Graphical presentation of the data since 1900 by age, period and birth cohort is used to explore in detail the differences in trends and to bring out, in particular, differences between the two countries in period and cohort effects. In addition to providing more details on well-known period effects — the secular decline in mortality in both countries (with Italy largely ‘catching up’ with France), and the immediate effects of the world wars — similarities and differences in cohort effects are also apparent. The two countries exhibit clear differences not only in terms of immediate casualties of the wars, but also in terms of the long-term impact of unfavourable wartime living conditions on the cohorts most affected.

Targeting lifesaving: demographic linkages between population structure and life expectancy.

Abstract: Life expectancy in a heterogeneous population can be increased by lowering mortality rates or by averting deaths at different ages, from different causes, or for different groups, as well as by changing the proportions of individuals in various risk groups, perhaps by altering the transition rates between groups Understanding how such changes in population structure affect life expectancy is useful in evaluating alternative lifesaving policies

Permanence for Replicator Equations

Abstract: Many dynamical systems display strange attractors and hence orbits that are so sensitive to initial conditions as to make any long-term prediction (except on a statistical basis) a hopeless task Such a lack of Ljapunov stability is not always crucial, however: Lagrange stability may be more relevant Thus, for some models the precise asymptotic behavior — whether it settles down to an equilibrium or keeps oscillating in a regular or irregular fashion — is less important than the fact that all orbits wind up in some preassigned bounded set The former problem can be impossibly hard to solve and the latter one easy to handle

Fuzzy Optimization and Mathematical Programming: A Brief Introduction and Survey

Abstract: Some general concepts and ideas related to fuzzy optimization as, e.g., a fuzzy constraint, fuzzy goal (objective function), fuzzy optimum, etc. are introduced first. A general fuzzy optimization problem involving these elements is formulated and solved. The cases of single and multiple objective functions are dealt with. Secondly, basic classes of fuzzy mathematical programming are discussed, including: fuzzy linear programming (with single and multiple objective functions), fuzzy integer programming, fuzzy 0–1 programming and fuzzy dynamic programming. Finally some newer, knowledge-based approaches are mentioned. An extended list of literature is included.

A Prototype Selection Committee Decision Analysis and Support System, SCDAS: Theoretical Background and Computer Implementation

Abstract: Many major decisions in public and private arenas are delegated to committees. The institution of a committee, though it has many shortcomings, remains an important aspect of many decision processes; the process of committee decision-making must therefore be improved. As a result of personal experiences with committees, the authors have developed a procedural concept and an automated aid for decision-making by committee, aimed in particular at a committee charged with the task of selecting from a finite set of alternatives.

Factors associated with the Finnish fertility decline since 1776.

Abstract: The analysis of annual age-specific fertility rates in Finland over more than 200 years reveals the existence of a significant early fertility decline at the end of the eighteenth century preceding the secular decline that started around 1910. A reconstruction of age-specific proportions married by a simulation model based on Coale's marriage model indicates that the mean age at marriage increased and the proportion ever-marrying decreased substantially during the period of the early fertility decline. A modification of the index of family limitation applied under certain assumptions to overall fertility rates also indicates that fertility was essentially natural until 1910. Cross-lagged correlation analysis shows that infant mortality does not influence subsequent fertility in the pre-modern period. Finally, a number of socio-economic indicators are related to fertility, and conclusions are drawn from the Finnish case about several hypotheses in the field of demographic transition.

Gradients for the evolution of bimatrix games.

Abstract: The evolutionary dynamics of bimatrix games is studied for rescaled partnership games and zero sum games. The former case leads to gradient systems. The selection equations for sexual and asexual reproduction of genotypes corresponding to mixed strategies are analysed. As examples, the origin of anisogamy and cyclic chases for predator-prey coevolution are studied.

Intelligent Decision Support for Technology Assessment: The Chemical Process Industry

Abstract: This paper describes the concepts behind and the software architecture of a simulation/optimization-based information and decision support system for the management of hazardous substances and their environment-technology interactions. This interactive system is implemented on a microcomputer workstation and combines data base management, system simulation and optimization, interactive data analysis and elements of decision technology with a symbolic display-oriented user interface. Important features of the interface are the use of several parallel or alternative styles of interaction and display, including color graphics and natural language. By combining quantitative methods with qualitative descriptions, and giving the user direct and interactive control over the system’s functions, human knowledge is integrated with formal approaches into a man-machine system through an intelligent and easily accessible user interface.

Inverse Problems in Multiobjective Dynamic Optimization

Abstract: One of the “practical” problems of control theory motivated primarily by environmental studies consists, loosely speaking, in the following. $$ \mathop x\limits^. = f(t,x,\omega ),\tau \leqslant t \leqslant \theta $$ (1.1) with “input variables” x (τ) = x 0; ω(•) = ω(θ + σ), τ - θ ≤ σ ≤ 0. These are restricted by inequalities $$ {h_j}({x^0}) \leqslant {\mu _{j,}}j = 1,...,p $$ (1.2) $$ {g_s}(\omega ( \bullet )) \leqslant {\beta _s},s = 1,...,q $$ (1.3) . Also given are the constraints on system trajectories — the “outputs” x(•) = x(θ + σ), τ - θ ≤ σ ≤ 0, i.e. $$ {\varphi _i}(x( \bullet )) \leqslant {\upsilon _i},i = 1,...,k $$ (1.4) .

Epsilon Solutions and Duality in Vector Optimization

Abstract: The study of epsilon solutions in vector optimization problems was started in 1979 by S S Kutateladze [1] These types of solutions are interesting because of their relation to non-differentiable optimization and the vector valued extensions of Ekeland’s variational principle as considered by P Loridan [2] and I Valyi [3], but computational aspects are perhaps even more important In practical situations, namely, we often stop the calculations at values that we consider sufficiently close to the optimal solution, or use algorithms that result in some approximates of the Pareto set Such procedures can result in epsilon solutions that are under study in this paper A paper by D J White [4] deals with this issue and investigates how well these solutions approximate the exact solutions

Fossil Energy and its Alternatives: A Problem Beyond Costs and Prices

Abstract: By interpreting primary energy forms as commodities, competing worldwide, Marchetti (1977) has revealed a remarkably stable substitution process. Figure 3.1 identifies the historical shifts from wood and farm wastes via coal to crude oil and natural gas. It is important to note that the regularity of these structural changes was not really influenced by such exceptional events as the First World War, the Second World War or the economic crisis of the 1920s and early 1930s. The 35 years following 1914 limited the growth of total energy consumption (Figure 3.2) but they were not able to interrupt the striving for ever cheaper and easier forms of energy.