Analysis of the Clearing Diversity-Preserving Mechanism

Clearing is a niching method inspired by the principle of assigning the available resources among a subpopulation to a single individual. The clearing procedure supplies these resources only to the best individual of each subpopulation: the winner. So far, its analysis has been focused on experimental approaches that have shown that clearing is a powerful diversity mechanism. We use empirical analysis to highlight some of the characteristics that makes it a useful mechanism and runtime analysis to explain how and why it is a powerful method. We prove that a (mu+1) EA with large enough population size and a phenotypic distance function always succeeds in optimising all functions of unitation for small niches in polynomial time, while a genotypic distance function requires exponential time. Finally, we prove that a (mu+1) EA with phenotypic and genotypic distances is able to find both optima in TWOMAX for large niches in polynomial expected time

On the Runtime Analysis of the Clearing Diversity-Preserving Mechanism

Clearing is a niching method inspired by the principle of assigning the available resources among a niche to a single individual. The clearing procedure supplies these resources only to the best individual of each niche: the winner. So far, its analysis has been focused on experimental approaches that have shown that clearing is a powerful diversity-preserving mechanism. Using rigorous runtime analysis to explain how and why it is a powerful method, we prove that a mutation-based evolutionary algorithm with a large enough population size, and a phenotypic distance function always succeeds in optimising all functions of unitation for small niches in polynomial time, while a genotypic distance function requires exponential time. Finally, we prove that with phenotypic and genotypic distances clearing is able to find both optima for Twomax and several general classes of bimodal functions in polynomial expected time. We use empirical analysis to highlight some of the characteristics that makes it a useful mechanism and to support the theoretical results

Vertical diversity and equilbrium growth

This paper examines the effect of an increase in vertical diversity in workers' skill on the long run growth rate of an economy. It uses a two-secror model where the techonology of the consumption-good sector is supermodular and that of the R&D sector is submodular. By adopting Grossman and Maggi's(2000) model to a framework of growth based on R&D, it shows first that diversity is condutive to growth. As the main innovation, communication gap is introduced among workers. It is then shown that growth may not be increasing with diversity. There may be an inverse-U shaped relationship.Diversity, talent distribution, supermodular technology, submodular technology, growth, skill, R&D, innovations

Theory and practice of population diversity in evolutionary computation

Divergence of character is a cornerstone of natural evolution. On the contrary, evolutionary optimization processes are plagued by an endemic lack of population diversity: all candidate solutions eventually crowd the very same areas in the search space. The problem is usually labeled with the oxymoron “premature convergence” and has very different consequences on the different applications, almost all deleterious. At the same time, case studies from theoretical runtime analyses irrefutably demonstrate the benefits of diversity. This tutorial will give an introduction into the area of “diversity promotion”: we will define the term “diversity” in the context of Evolutionary Computation, showing how practitioners tried, with mixed results, to promote it. Then, we will analyze the benefits brought by population diversity in specific contexts, namely global exploration and enhancing the power of crossover. To this end, we will survey recent results from rigorous runtime analysis on selected problems. The presented analyses rigorously quantify the performance of evolutionary algorithms in the light of population diversity, laying the foundation for a rigorous understanding of how search dynamics are affected by the presence or absence of diversity and the introduction of diversity mechanisms

Force-imitated particle swarm optimization using the near-neighbor effect for locating multiple optima

Copyright @ Elsevier Inc. All rights reserved.Multimodal optimization problems pose a great challenge of locating multiple optima simultaneously in the search space to the particle swarm optimization (PSO) community. In this paper, the motion principle of particles in PSO is extended by using the near-neighbor effect in mechanical theory, which is a universal phenomenon in nature and society. In the proposed near-neighbor effect based force-imitated PSO (NN-FPSO) algorithm, each particle explores the promising regions where it resides under the composite forces produced by the “near-neighbor attractor” and “near-neighbor repeller”, which are selected from the set of memorized personal best positions and the current swarm based on the principles of “superior-and-nearer” and “inferior-and-nearer”, respectively. These two forces pull and push a particle to search for the nearby optimum. Hence, particles can simultaneously locate multiple optima quickly and precisely. Experiments are carried out to investigate the performance of NN-FPSO in comparison with a number of state-of-the-art PSO algorithms for locating multiple optima over a series of multimodal benchmark test functions. The experimental results indicate that the proposed NN-FPSO algorithm can efficiently locate multiple optima in multimodal fitness landscapes.This work was supported in part by the Key Program of National Natural Science Foundation (NNSF) of China under Grant 70931001, Grant 70771021, and Grant 70721001, the National Natural Science Foundation (NNSF) of China for Youth under Grant 61004121, Grant 70771021, the Science Fund for Creative Research Group of NNSF of China under Grant 60821063, the PhD Programs Foundation of Ministry of Education of China under Grant 200801450008, and in part by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/1 and Grant EP/E060722/2

Too-connected-to-fail Institutions and Payments System’s Stability: Assessing Challenges for Financial Authorities

The most recent episode of market turmoil exposed the limitations resulting from the traditional focus on too-big-to-fail institutions within an increasingly systemic-crisis-prone financial system, and encouraged the appearance of the too-connected-to-fail (TCTF) concept. The TCTF concept conveniently broadens the base of potential destabilizing institutions beyond the traditional banking-focused approach to systemic risk, but requires methodologies capable of coping with complex, cross-dependent, context-dependent and non-linear systems. After comprehensively introducing the rise of the TCTF concept, this paper presents a robust, parsimonious and powerful approach to identifying and assessing systemic risk within payments systems, and proposes some analytical routes for assessing financial authorities’ challenges. Banco de la Republica’s approach is based on a convenient mixture of network topology basics for identifying central institutions, and payments systems simulation techniques for quantifying the potential consequences of central institutions failing within Colombian large-value payments systems. Unlike econometrics or network topology alone, results consist of a rich set of quantitative outcomes that capture the complexity, cross-dependency, context-dependency and non-linearity of payments systems, but conveniently disaggregated and dollar-denominated. These outcomes and the proposed analysis provide practical information for enhanced policy and decision-making, where the ability to measure each institution’s contribution to systemic risk may assist financial authorities in their task to achieve payments system’s stability.Payments systems, too-connected-to-fail, too-big-to-fail, systemic risk, network topology, simulation, central bank liquidity. Classification JEL:E58, E44, C63, G21, D85.

Potential synergies between existing multilateral environmental agreements in the implementation of Land Use, Land Use Change and Forestry activities

There is potential for synergy between the global environmental conventions on climate change, biodiversity and desertification: changes in land management and land use undertaken to reduce net greenhouse gas emissions can simultaneously deliver positive outcomes for conservation of biodiversity, and mitigation of desertification and land degradation. However, while there can be complementarities between the three environmental goals, there are often tradeoffs. Thus, the challenge lies in developing land use policies that promote optimal environmental outcomes, and in implementing these locally to promote sustainable development. The paper considers synergies and tradeoffs in implementing land use measures to address the objectives of the three global environmental conventions, both from an environmental and economic perspective. The intention is to provide environmental scientists and policy makers with a broad overview of these considerations, and the benefits of addressing the conventions simultaneously.Climate change, LULUCF, Biodiversity, Desertification, Sustainable development.

Paiements pour services environnementaux et développement. Coupler incitation à la conservation et investissement

Rémunérer des communautés ou des producteurs pour maintenir la qualité de l'eau ou la biodiversité; inciter des agriculteurs à adopter des pratiques respectueuses de l'environnement; rétribuer les pays en développement pour ne pas déboiser, et diminuer ainsi les émissions de CO2: l'intérêt pour les paiements pour services environnementaux (PSE) s'accroît partout dans le monde. Pourtant les expériences passées montrent que les PSE ne sont pas indemnes de dysfonctionnements : le critère utilisé pour déterminer le montant ; les modalités d'évaluation de l'efficacité ; l'utilisation incertaine des paiements... D'où la proposition de coupler les incitations directes à protéger les écosystèmes, et notamment les forêts, avec l'intensification écologique de l'agriculture et l'investissement dans le foncier

Privacy-Preserving Design of Data Processing Systems in the Public Transport Context

The public transport network of a region inhabited by more than 4 million people is run by a complex interplay of public and private actors. Large amounts of data are generated by travellers, buying and using various forms of tickets and passes. Analysing the data is of paramount importance for the governance and sustainability of the system. This manuscript reports the early results of the privacy analysis which is being undertaken as part of the analysis of the clearing process in the Emilia-Romagna region, in Italy, which will compute the compensations for tickets bought from one operator and used with another. In the manuscript it is shown by means of examples that the clearing data may be used to violate various privacy aspects regarding users, as well as (technically equivalent) trade secrets regarding operators. The ensuing discussion has a twofold goal. First, it shows that after researching possible existing solutions, both by reviewing the literature on general privacy-preserving techniques, and by analysing similar scenarios that are being discussed in various cities across the world, the former are found exhibiting structural effectiveness deficiencies, while the latter are found of limited applicability, typically involving less demanding requirements. Second, it traces a research path towards a more effective approach to privacy-preserving data management in the specific context of public transport, both by refinement of current sanitization techniques and by application of the privacy by design approach. Available at: https://aisel.aisnet.org/pajais/vol7/iss4/4

The Sound of Falling Trees: Integrating Environmental Justice Principles into the Climate Change Framework for Reducing Emissions from Deforestation and Degradation (REDD)

Charitable giving is of great value to society. In particular, wealthy individuals and their families have the ability to make a significant impact on society. Many research papers and wealth briefings try to understand the multi-billion dollar global charitable giving market. These studies have provided valuable insights, but often miss the viewpoint of High Net Worth Individuals (HNWIs). Our comparative research provides a unique perspective on wealthy individuals in France and in the Netherlands. It is the first research to use the same methods in two different countries, which allows us to make solid comparisons. We asked 961 High Net Worth Individuals about their charitable giving behaviour and their knowledge of and interest in impact investing. What causes do our clients value most? How much do they give annually? And how does charitable giving relate to impact investing for the clients? Does the financial return or social return drive individuals to invest with impact? Please join us in this study to explore charitable giving from the giver’s perspective