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Afscheidscollege van Prof.Dr. A. Staal uitgesproken op 1 februari 199

A Simple Algorithm for Estimating Distribution Parameters from nn-Dimensional Randomized Binary Responses

Randomized response is attractive for privacy preserving data collection because the provided privacy can be quantified by means such as differential privacy. However, recovering and analyzing statistics involving multiple dependent randomized binary attributes can be difficult, posing a significant barrier to use. In this work, we address this problem by identifying and analyzing a family of response randomizers that change each binary attribute independently with the same probability. Modes of Google's Rappor randomizer as well as applications of two well-known classical randomized response methods, Warner's original method and Simmons' unrelated question method, belong to this family. We show that randomizers in this family transform multinomial distribution parameters by an iterated Kronecker product of an invertible and bisymmetric $2 \times 2$ matrix. This allows us to present a simple and efficient algorithm for obtaining unbiased maximum likelihood parameter estimates for $k$-way marginals from randomized responses and provide theoretical bounds on the statistical efficiency achieved. We also describe the efficiency - differential privacy tradeoff. Importantly, both randomization of responses and the estimation algorithm are simple to implement, an aspect critical to technologies for privacy protection and security.Comment: Accepted at Information Security - 21th International Conference, ISC 2018. Adapted to meet article length requirements. Fixed typo. Results unchange

Functional Analytic Multisensory Environmental Therapy for People with Dementia

This paper introduces Functional Analytic Multisensory Environmental Therapy (FAMSET) for use with elders with dementia while using a multisensory environment/snoezelen room. The model introduces behavioral theory and practice to the multisensory environment treatment, addressing assessment, and, within session techniques, integrating behavioral interventions with emotion-oriented care. A modular approach is emphasized to delineate different treatment phases for multisensory environment therapy. The aim of the treatment is to provide a safe and effective framework for reducing the behavioral disturbance of the disease process, increasing elder well-being, and to promote transfer of positive effects to other environments outside of the multisensory treatment room

CATTLE AS ASSETS: ASSESSMENT OF NON-MARKET BENEFITS FROM CATTLE IN SMALLHOLDER KENYAN CROP-LIVESTOCK SYSTEMS

This paper uses data from a survey of two hundred and fifty cattle households in three cattle keeping systems; intensive, semi-intensive and extensive systems to estimate the value of non-market, socio-economic benefits of cattle in Kenya. These benefits of cattle keeping are of special importance in developing countries, where financial markets function poorly and opportunities for risk management through formal insurance generally absent. However, when estimating the total contribution of livestock, these non-market functions are often ignored since they are difficult to value, yet they may contribute to a better understanding of livestock production systems. The use of contingent valuation method is employed in this study to elicit these non-market values. Econometric estimations are then used to assess the factors influencing the non-market benefits function. The results indicate that these benefits are highly valued by cattle keepers and comprise approximately 20% of the animal's total value across the three systems. They are influenced by various production system and household related factors. Implications for policy are drawn.Livestock Production/Industries, QQ112, QQ118, DD223,

How motifs condition critical thresholds for tipping cascades in complex networks: Linking Micro- to Macro-scales

In this study, we investigate how specific micro interaction structures (motifs) affect the occurrence of tipping cascades on networks of stylized tipping elements. We compare the properties of cascades in Erd\"os-R\'enyi networks and an exemplary moisture recycling network of the Amazon rainforest. Within these networks, decisive small-scale motifs are the feed forward loop, the secondary feed forward loop, the zero loop and the neighboring loop. Of all motifs, the feed forward loop motif stands out in tipping cascades since it decreases the critical coupling strength necessary to initiate a cascade more than the other motifs. We find that for this motif, the reduction of critical coupling strength is 11% less than the critical coupling of a pair of tipping elements. For highly connected networks, our analysis reveals that coupled feed forward loops coincide with a strong 90% decrease of the critical coupling strength. For the highly clustered moisture recycling network in the Amazon, we observe regions of very high motif occurrence for each of the four investigated motifs suggesting that these regions are more vulnerable. The occurrence of motifs is found to be one order of magnitude higher than in a random Erd\"os-R\'enyi network. This emphasizes the importance of local interaction structures for the emergence of global cascades and the stability of the network as a whole

Dairy development for the resource poor. Part 3: Pakistan and India dairy development case studies

The process of dairy development that this study addresses is driven by underlying fundamental changes in economic growth, the value of resources and consumer demand. However, it is also shaped by public policies, interventions and investment decisions and will be accompanied by changes in impact on incomes, opportunities and livelihoods of producers and changes in opportunities and returns for market agents and investors. This study examines dairy development in two key dairy producing regions in the developing world: East Africa and South Asia. The aim of the study is to analyse the trends in dairy development in these two regions and identify their key determinants, to analyse the impact of policy interventions on those trends and to identify impacts of dairy development, particularly on the poor. The study is reported in three parts: Part 1 presents a conceptual framework for dairy development, followed by a section presenting a regional analysis of dairy development trends across all the countries in the two regions and a synthesis of the outcomes of the case study analyses (see below), highlighting implications for policy interventions and investment, including proposing a model for pro-poor dairy development. Parts 2 and 3 consist of in-depth case studies and analyses of dairy development trends, determinants and outcomes in Kenya and Ethiopia (Part 2) and India and Pakistan (Part 3 – this report)

Dairy development for the resource poor. Part 2: Kenya and Ethiopia. Dairy development case studies

The process of dairy development that this study addresses is driven by underlying fundamental changes in economic growth, the value of resources and consumer demand. However, it is also shaped by public policies, interventions and investment decisions and will be accompanied by changes in impact on incomes, opportunities and livelihoods of producers and changes in opportunities and returns for market agents and investors. This study examines dairy development in two key dairy producing regions in the developing world: East Africa and South Asia. The aim of the study is to analyse the trends in dairy development in these two regions and identify their key determinants, to analyse the impact of policy interventions on those trends and to identify impacts of dairy development, particularly on the poor. The study is reported in three parts: Part 1 presents a conceptual framework for dairy development, followed by a section presenting a regional analysis of dairy development trends across all the countries in the two regions and a synthesis of the outcomes of the case study analyses (see below), highlighting implications for policy interventions and investment, including proposing a model for pro-poor dairy development. Parts 2 and 3 consist of in-depth case studies and analyses of dairy development trends, determinants and outcomes in Kenya and Ethiopia (Part 2 – this report) and India and Pakistan (Part 3)

Dynamics of Tipping Cascades on Complex Networks

Tipping points occur in diverse systems in various disciplines such as ecology, climate science, economy or engineering. Tipping points are critical thresholds in system parameters or state variables at which a tiny perturbation can lead to a qualitative change of the system. Many systems with tipping points can be modeled as networks of coupled multistable subsystems, e.g. coupled patches of vegetation, connected lakes, interacting climate tipping elements or multiscale infrastructure systems. In such networks, tipping events in one subsystem are able to induce tipping cascades via domino effects. Here, we investigate the effects of network topology on the occurrence of such cascades. Numerical cascade simulations with a conceptual dynamical model for tipping points are conducted on Erd\H{o}s-R\'enyi, Watts-Strogatz and Barab\'asi-Albert networks. Additionally, we generate more realistic networks using data from moisture-recycling simulations of the Amazon rainforest and compare the results to those obtained for the model networks. We furthermore use a directed configuration model and a stochastic block model which preserve certain topological properties of the Amazon network to understand which of these properties are responsible for its increased vulnerability. We find that clustering and spatial organization increase the vulnerability of networks and can lead to tipping of the whole network. These results could be useful to evaluate which systems are vulnerable or robust due to their network topology and might help to design or manage systems accordingly.Comment: 22 pages, 12 figure