4,567 research outputs found

    To weight or not to weight, that is the question: the design of a composite indicator of landscape fragmentation

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    Composite indicators (CIs), i.e., combinations of many indicators in a unique synthetizing measure, are useful for disentangling multisector phenomena. Prominent questions concern indicators’ weighting, which implies time-consuming activities and should be properly justified. Landscape fragmentation (LF), the subdivision of habitats in smaller and more isolated patches, has been studied through the composite index of landscape fragmentation (CILF). It was originally proposed by us as an unweighted combination of three LF indicators for the study of the phenomenon in Sardinia, Italy. In this paper, we aim at presenting a weighted release of the CILF and at developing the Hamletian question of whether weighting is worthwhile or not. We focus on the sensitivity of the composite to different algorithms combining three weighting patterns (equalization, extraction by principal component analysis, and expert judgment) and three indicators aggregation rules (weighted average mean, weighted geometric mean, and weighted generalized geometric mean). The exercise provides the reader with meaningful results. Higher sensitivity values signal that the effort of weighting leads to more informative composites. Otherwise, high robustness does not mean that weighting was not worthwhile. Weighting per se can be beneficial for more acceptable and viable decisional processes

    A generalised dynamic factor model for the Belgian economy - Useful business cycle indicators and GDP growth forecasts

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    This paper aims to extract the common variation in a data set of 509 conjunctural series as an indication of the Belgian business cycle. The data set contains information on business and consumer surveys of Belgium and its neighbouring countries, macroeconomic variables and some worldwide watched indicators such as the ISM and the OECD confidence indicators. The statistical framework used is the One-sided Generalised Dynamic Factor Model developed by Forni, Hallin, Lippi and Reichlin (2005). The model splits the series in a common component, driven by the business cycle, and an idiosyncratic component. Well-known indicators such as the EC economic sentiment indicator for Belgium and the NBB overall synthetic curve contain a high amount of business cycle information. Furthermore, the richness of the model allows to determine the cyclical properties of the series and to forecast GDP growth all within the same unified setting. We classify the common component of the variables into leading, lagging and coincident with respect to the common component of quarter-on-quarter GDP growth. 22% of the variables are found to be leading. Amongst the most leading variables we find asset prices and international confidence indicators such as the ISM and some OECD indicators. In general, national business confidence surveys are found to coincide with Belgian GDP, while they lead euro area GDP and its confidence indicators. Consumer confidence seems to lag. Although the model captures the dynamic common variation contained in the data set, forecasts based on that information are insufficient to deliver a good proxy for GDP growth as a result of a nonnegligible idiosyncratic part in GDP's variance. Lastly, we explore the dependence of the model's results on the data set and show through a data reduction process that the idiosyncratic part of GDP's quarter-on-quarter growth can be dramatically reduced. However, this does not improve the forecasts.Dynamic factor model, business cycle, leading indicators, forecasting, data reduction.

    Sustainable Development Indicator Frameworks and Initiatives

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    Agricultural and Food Policy, Environmental Economics and Policy, Farm Management, Production Economics,

    Modelling cyber-security experts' decision making processes using aggregation operators

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    An important role carried out by cyber-security experts is the assessment of proposed computer systems, during their design stage. This task is fraught with difficulties and uncertainty, making the knowledge provided by human experts essential for successful assessment. Today, the increasing number of progressively complex systems has led to an urgent need to produce tools that support the expert-led process of system-security assessment. In this research, we use Weighted Averages (WAs) and Ordered Weighted Averages (OWAs) with Evolutionary Algorithms (EAs) to create aggregation operators that model parts of the assessment process. We show how individual overall ratings for security components can be produced from ratings of their characteristics, and how these individual overall ratings can be aggregated to produce overall rankings of potential attacks on a system. As well as the identification of salient attacks and weak points in a prospective system, the proposed method also highlights which factors and security components contribute most to a component's difficulty and attack ranking respectively. A real world scenario is used in which experts were asked to rank a set of technical attacks, and to answer a series of questions about the security components that are the subject of the attacks. The work shows how finding good aggregation operators, and identifying important components and factors of a cyber-security problem can be automated. The resulting operators have the potential for use as decision aids for systems designers and cyber-security experts, increasing the amount of assessment that can be achieved with the limited resources available

    Globalization, Economic Freedom and Human Rights

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    Using the KOF Index of Globalization and two indices of economic freedom, we empirically analyze whether globalization and economic liberalization affect governments’ respect for human rights using a panel of 106 countries over the 1981-2004 period. According to our results, physical integrity rights significantly and robustly increase with globalization and economic freedom, while empowerment rights are not robustly affected. Due to the lack of consensus about the appropriate level of empowerment rights as compared to the outright rejection of any violation of physical integrity rights, the global community is presumably less effective in promoting empowerment rights.human rights, globalization, economic freedom, liberalization

    Characterising the security of power system topologies through a combined assessment of reliability, robustness, and resilience

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    Electricity has a prominent role in modern economies; therefore, ensuring the availability of electricity supply should be a top priority for policymakers. The joint assessment of reliability, robustness, and resilience can be a useful criterion to characterise different topologies and improve the security of supply. This paper proposes a novel integrated analysis of these three attributes to quantify the security of power grid topologies. Hence, eight case studies with different topologies created using the IEEE 24-bus reliability test system were analysed. Reliability was evaluated by applying the sequential Monte Carlo approach, robustness was evaluated by simulating cascading failures, and resilience was evaluated by analysing recovery curves. The different indicators associated with each of the three evaluations were then calculated. The results obtained were discussed both graphically and quantitatively in a novel three-dimensional representation, where the importance of joint analysis was also highlighted. The proposed method can serve as an additional tool for planners to identify possible investments or improvements in power system topologies

    Benchmarking OECD Countries’ Sustainable Development Performance: A Goal-Specific PCA Approach

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    In this thesis, the current status of the Organisation for Economic Co-operation and Development (OECD) countries’ sustainable development performance towards reaching the recently announced 2030 Agenda (17 UN Sustainable Development Goals (SDGs)) was investigated. Over 90 social, economic and environmental sustainability indicators were considered for the performance assessment of OECD countries towards reaching the targeted SDGs. The current weighted averaging approach used in the recent SDG Index and Dashboards Report was used as the benchmark and its limitations were discussed. To overcome the limitations, a novel Goal Specific Principal Component Analysis (GS-PCA) approach was proposed to create composite sustainability index scores for OECD countries, which takes into account the variance in the dataset and deals effectively with the deteriorating impacts of multicollinearity. The study period included 2017 and 2018, which covered the most recent available data. A total of 34 PCA models were developed, which yielded country and SDG-focused overall and goal-specific sustainable development index (SDI) scores. Results were compared with recent benchmark reports published in 2017 and 2018; and were statistically validated. Findings indicated that the standard deviation of the scores and ranks were found to be substantially greater with the proposed GS-PCA approach. The 2017 and 2018 performances were compared visually and statistically. Even though there was increasing performance observed in some SDGs and some countries, there was no statistically significant difference found between the 2017 and 2018 years. In addition, substantial differences were observed in the scores and ranks of mediocre and poor performing countries compared to the benchmark report, while both the results were found to be strongly positively correlated. Overall, the UN SDG Dashboard and Index reports findings were found to be quite optimistic compared to the results obtained with the proposed GS-PCA approach

    Measuring global water security towards sustainable development goals

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    Water plays an important role in underpinning equitable, stable and productive societies and ecosystems. Hence, United Nations recognized ensuring water security as one (Goal 6) of the seventeen sustainable development goals (SDGs). Many international river basins are likely to experience 'low water security' over the coming decades. Water security is rooted not only in the physical availability of freshwater resources relative to water demand, but also on social and economic factors (e.g. sound water planning and management approaches, institutional capacity to provide water services, sustainable economic policies). Until recently, advanced tools and methods are available for the assessment of water scarcity. However, quantitative and integrated-physical and socio-economic-approaches for spatial analysis of water security at global level are not available yet. In this study, we present a spatial multi-criteria analysis framework to provide a global assessment of water security. The selected indicators are based on Goal 6 of SDGs. The term 'security' is conceptualized as a function of 'availability', 'accessibility to services', 'safety and quality', and 'management'. The proposed global water security index (GWSI) is calculated by aggregating indicator values on a pixel-by-pixel basis, using the ordered weighted average method, which allows for the exploration of the sensitivity of final maps to different attitudes of hypothetical policy makers. Our assessment suggests that countries of Africa, South Asia and Middle East experience very low water security. Other areas of high water scarcity, such as some parts of United States, Australia and Southern Europe, show better GWSI values, due to good performance of management, safety and quality, and accessibility. The GWSI maps show the areas of the world in which integrated strategies are needed to achieve water related targets of the SDGs particularly in the African and Asian continents

    Architecture value mapping: using fuzzy cognitive maps as a reasoning mechanism for multi-criteria conceptual design evaluation

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    The conceptual design phase is the most critical phase in the systems engineering life cycle. The design concept chosen during this phase determines the structure and behavior of the system, and consequently, its ability to fulfill its intended function. A good conceptual design is the first step in the development of a successful artifact. However, decision-making during conceptual design is inherently challenging and often unreliable. The conceptual design phase is marked by an ambiguous and imprecise set of requirements, and ill-defined system boundaries. A lack of usable data for design evaluation makes the problem worse. In order to assess a system accurately, it is necessary to capture the relationships between its physical attributes and the stakeholders\u27 value objectives. This research presents a novel conceptual architecture evaluation approach that utilizes attribute-value networks, designated as \u27Architecture Value Maps\u27, to replicate the decision makers\u27 cogitative processes. Ambiguity in the system\u27s overall objectives is reduced hierarchically to reveal a network of criteria that range from the abstract value measures to the design-specific performance measures. A symbolic representation scheme, the 2-Tuple Linguistic Representation is used to integrate different types of information into a common computational format, and Fuzzy Cognitive Maps are utilized as the reasoning engine to quantitatively evaluate potential design concepts. A Linguistic Ordered Weighted Average aggregation operator is used to rank the final alternatives based on the decision makers\u27 risk preferences. The proposed methodology provides systems architects with the capability to exploit the interrelationships between a system\u27s design attributes and the value that stakeholders associate with these attributes, in order to design robust, flexible, and affordable systems --Abstract, page iii
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