Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Evaluation of the impact of extrinsic rewards on user engagement in a health promotion context
    Nuijten, Raoul C.Y. ; Gorp, Pieter M.E. Van; Kaymak, Uzay ; Simons, Monique ; Kemperman, Astrid D.A.M. ; Berg, Pauline E.W. Van Den - \ 2019
    In: 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019. - Berlin, Germany : Institute of Electrical and Electronics Engineers Inc. (Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ) - ISBN 9781538613115 - p. 3600 - 3604.
    extrinsic rewards - health promotion - mHealth - social proof principle

    Despite the many mHealth solutions available, it remains unclear what their success factors are. Specifically, there has been controversy on the effectiveness of extrinsic rewards. This study evaluates two design elements of an mHealth solution -i.e., social proof and tangible rewards -and their impact on user engagement. During a four-week campaign, a sample of 143 university staff members engaged in a health promotion campaign. Participants were randomly distributed over one of three treatment groups. It was found that the introduction of a sufficiently meaningful, unexpected, and customized extrinsic reward can engage participants significantly more in a health promotion context.

    Factors affecting farmers' adoption of integrated rice-fish farming systems in the Mekong delta, Vietnam
    Bosma, R.H. ; Nhan, D.K. ; Udo, H.M.J. ; Kaymak, U. - \ 2012
    Reviews in Aquaculture 4 (2012)3. - ISSN 1753-5123 - p. 178 - 190.
    agriculture-aquaculture systems - decision-making - goals - management - values
    This study investigated the determinants of the adoption of improved rice–fish farming systems in the Mekong delta to support policy making, agricultural land-use planning and extension of integrated rice–fish farming. Recently these systems have been referred to as adaptations to climate change, while traditional rice–fish systems have often been abandoned. In 2006, we carried out surveys among 94 farmers either practising rice monoculture or having an improved rice–fish system. We analysed data among others with binary logistic regression and simulated adoption by using fuzzy logic. Per capita and per hectare incomes of households practising rice–fish systems were nearly double, while their farm size was 1.3 times larger than that of the rice monoculture farms. Households with larger homesteads, i.e. neighbouring irrigated fields and ponds, better access to financial capital and more know-how of rice and fish culture and their integration, were more likely to adopt rice–fish systems. Previously identified drivers and factors for adoption, such as an appropriate agro-ecological context and the farmer’s education and training level, were confirmed. Promoting rice–fish systems needs participatory extension and research approaches for sustainable agriculture strategies such as integrated pest management (IPM) in which farmers, trainers and researchers optimize technologies in constantly changing contexts.
    A generic methodology for developing fuzzy decision models
    Bosma, R.H. ; Berg, J. van den; Kaymak, Uzay ; Udo, H.M.J. ; Verreth, J.A.J. - \ 2012
    Expert Systems with Applications 39 (2012)1. - ISSN 0957-4174 - p. 1200 - 1210.
    expert-system - simulation-models - support-system - mekong delta - crop - aquaculture - knowledge - integration - management - scale
    An important paradigm in decision-making models is utility-maximization where most models do not include actors’ motives. Fuzzy set theory on the other hand offers a method to simulate human decision-making. However, the literature describing expert-driven fuzzy logic models, rarely gives precise details on the methodology (to be) used. To fill the gap, this paper describes a methodology of 10 steps to model individual actor’s drivers, motives, hereby taking into account the ecological, social and economic context. Testing the methodology on the composition of mixed farming systems in the Mekong Delta, Vietnam, showed that manual model development is not a waterfall approach but requires feedback loops, except for model implementation. Using feed-back loops, the proposed 10 step method allowed to include human drivers and motives other than utility-maximization and to maintain a degree of transparency hard to achieve when using automated procedures.
    Using fuzzy logic modelling to simulate farmers' decision-making on diversification and integration in the Mekong Delta, Vietnam
    Bosma, R.H. ; Kaymak, U. ; Berg, J. van den; Udo, H.M.J. ; Verreth, J.A.J. - \ 2011
    Soft Computing 15 (2011)2. - ISSN 1432-7643 - p. 295 - 310.
    system - aquaculture - management - crop - environment - knowledge - goals - scale
    To reveal farmers’ motives for on-farm diversification and integration of farming components in the Mekong Delta, Vietnam, we developed a fuzzy logic model (FLM) using a 10-step approach. Farmers’ decision-making was mimicked in a three-layer hierarchical architecture of fuzzy inference systems, using data of 72 farms. The model includes three variables for family motives of diversification, six variables related to component integration, next to variables for the production factors and for farmers’ appreciation of market prices and know-how on 10 components. To obtain a good classification rate of the less frequent activities, additional individual fine-tuning was necessary after general model calibration. To obtain the desired degree of sensitivity to each variable, it was necessary to use up to five linguistic values for some of the input and output variables in the intermediate hierarchical layers. Model’s sensitivity to motivational variables determining diversification and integration was of the same magnitude as its sensitivity to market prices and farmers’ know-how of the activities, but less than its sensitivity to labour, capital and land endowment. Modelling to support strategic decision-making seems too elaborate for individual farms, but FLM will be useful to integrate farmers’ opinions in strategic decision-making at higher hierarchical levels
    Modeling take-up of rice-fish systems with fuzzy logic
    Bosma, R.H. ; Nhan, D.K. ; Udo, H.M.J. ; Kaymak, U. - \ 2008
    Using fuzzy logic models to reveal farmers' motives to integrate livestock, fish, and crops
    Bosma, R.H. - \ 2007
    Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Henk Udo; J. van den Berg; U. Kaymak. - [S.l.] : S.n. - ISBN 9789085047803 - 144
    boeren - motivatie - vage logica - simulatiemodellen - besluitvorming - veehouderij - visteelt - landbouwplantenteelt - vietnam - geïntegreerde bedrijfssystemen - farmers - motivation - fuzzy logic - simulation models - decision making - livestock farming - fish culture - crop husbandry - vietnam - integrated farming systems
    Rural extension services have changed paradigm and shifted to more participatory approaches, whereas in common mathematical models of farming systems, farmers’ motivation is solely represented by ‘utility maximisation’. While globally, farmers specialise, in Vietnam the rice-based systems have diversified into more sustainable integrated agriculture–aquaculture. We gathered data from 144 farms in six villages in two ecological zones of the Mekong Delta, Vietnam. Using the livelihood framework we conceptualised farmers’ decision-making in a fuzzy logic model that can deal with subjective linguistic statements through ‘if–then’ rules. The desire to improve livelihoods and diet, mainly for their children’ well-being was the farmers’ main motive for diversification. Livestock, including fish, was essential in the expansion and accumulation stages of the nuclear families’ life-course having five stages. In 10 recursive steps we developed a model of farmers’ decision-making in a transparent hierarchical tree composed of several Mamdani-based inference systems, each with its rule base. Model conceptualisation, variables selection, model structuring, and definition of linguistic values, membership functions and rule base were based on a first set of data that was completed before calibration. In a pilot, the simulation of the frequency distribution of four fish-production systems was good, but classification of individual farmers was poor. Using composed variables for land, water, labour and capital decreased the fuzziness of the inference in this pilot model. In a more elaborated three-layer model, the whole farm composition was simulated using variables for the production factors, farmers’ appreciation of prices, farmer’s know-how of 10 activities, operational variables of social motives for integration and diversification as well as for risk-taking behaviour and for rice food security. Model’s classification of individual farmers in the delta was good for the land-based activities but poor for the livestock activities. A test on the hill farmers’ dataset showed that the model was context-specific. The model’s sensitivity to the social variables determining diversification and integration was of the same magnitude as its sensitivity to product’s prices and farmer’s know-how, but smaller than its sensitivity to labour, capital and land endowment. We conclude that farmers’ decision-making can be simulated using a fuzzy logic model. In the Mekong Delta farm diversification and integration are driven by labour, income, homestead area, number of young children, index of integration, household life-course, and level of education and age of the household head, in decreasing order. The choice of a component depends on the household’s assets and specific know-how, and on marketability. Farm models that do not include family-related motivations might be less reliable than generally suggested.
    Using fuzzy logic to simulate the composition of farming systems in the Mekong Delta
    Bosma, R.H. ; Berg, J. van den; Kaymak, U. ; Udo, H.M.J. ; Verreth, J.A.J. - \ 2006
    In: Animal production and sustainable agriculture in the tropic. Part 2. Supporting papers. Proc. 4th ISTAP, 8-9 november 2006, Yogjakarta, Indonesia. - , Indonesia : - ISBN 9789799724397 - p. 484 - 494.
    Assessing and modelling farmers' decision-making on integrating aquaculture into agriculture in the Mekong Delta
    Bosma, R.H. ; Thanh Phong, Le; Kaymak, U. ; Berg, J. van den; Udo, H.M.J. ; Mensvoort, M.E.F. van; Quang Tri, Le - \ 2006
    NJAS Wageningen Journal of Life Sciences 53 (2006)3/4. - ISSN 1573-5214 - p. 281 - 300.
    diversificatie - bedrijfssystemen - visteelt - visserij - bedrijfsvoering - besluitvorming - modellen - vietnam - landgebruik - wetlands - agro-ecologie - diversification - farming systems - land use - wetlands - fish culture - fisheries - management - decision making - models - vietnam - agroecology
    Contrary to the global trend of specialization within agriculture, the rice-based Vietnamese production systems have diversified into integrated agriculture¿aquaculture systems. Economic liberalization in 1986 resulted in an explosive increase in rice production and a rapid diversification. This paper describes the history and dynamics of these systems in the Mekong Delta, and the farmers¿ decisionmaking in this process. Subsequently, we use fuzzy logic to simulate farmers¿ decisions to opt for no aquaculture or one of four fish-production systems: waste-fed, pellet-fed, rice¿fish, and ditch¿dike, i.e., fish¿fruit. In a reaction to changing market opportunities the farmers developed these systems either from the depressions left after building a homestead or after raising dikes to improve irrigation and drainage for rice and fruit trees. The decision-making was simulated in a two-level hierarchy decisiontree. The first layer handles the farmer¿s production preferences for rice, fruit or fish, with composed variables for land, water, labour, capital and market. The second layer simulates the choice between five options: no fish, and the four alternative fish-production systems. The model allowed a farmer to practise different aquaculture systems at the same time. The fuzzy model simulation predicted the frequency distribution of fish production systems fairly accurately, but performed poorly when classifying individual farmers. To improve the accuracy of the simulation, additional rules can be specified and more factors considered for each product by adding a third layer to the decision-tree and replacing the composed variables with fuzzy rules
    Fuzzy Modelling of Farmer Motivations for Integrated Farming in the Vietnamese Mekong Delta
    Bosma, R.H. ; Kaymak, U. ; Berg, J. van den; Udo, H.M.J. - \ 2005
    In: Proceedings of the 14th IEEE International Conference on Fuzzy Systems, May 22-25, 2005 Reno, Nevada Los Alamitos, USA : IEEE Publications Office - p. 827 - 832.
    Fuzzy modelling of farmer motivations for integrated farming in the Vietnamese Mekong Delta
    Bosma, R.H. ; Kaymak, U. ; Berg, J. van den; Udo, H.M.J. - \ 2005
    Analysing Mekong Delta farmers' motivations for aquaculture with fuzzy logic
    Bosma, R.H. ; Kaymak, U. ; Berg, J. van den; Udo, H.M.J. ; Verreth, J.A.J. - \ 2005
    In: Book of Abstracts World Aquaculture 2005, Bali, Indonesia, 9-13 May, 2005 - p. 91 - 91.
    Elicitation of expert knowledge for fuzzy evaluation of agricultural production systems
    Cornelissen, A.M.G. ; Berg, J. van den; Koops, W.J. ; Kaymak, U. - \ 2003
    Agriculture, Ecosystems and Environment 95 (2003). - ISSN 0167-8809 - p. 1 - 18.
    sustainability indicators - laying hens - membership - sets - welfare
    Public concern nowadays is an important frame of reference for the development of agricultural production systems. The development of such systems, therefore, involves both society level and production system level. Following Zadeh's 'principle of incompatibility', information obtained at production system level is interpreted at society level in linguistic terms. Fuzzy models promise to be a valuable tool as they link measurable information to linguistic interpretation using membership functions (MFs). The objective of this paper is to outline a procedure which deals with criticism regarding the inherent subjectivity in the construction of MFs when using expert knowledge. The procedure guarantees the selection of appropriate expert knowledge, and provides a guideline supporting the selection of methods to elicit expert knowledge and construct MFs. Also on the basis of the results in an illustrative example, it is concluded that the procedure outlined in this paper suitably deals with criticism regarding MFs and, therefore, enables a practical implementation of fuzzy evaluation of agricultural production systems. Current research implements the procedure to build a fuzzy model which evaluates egg production systems in relation to public concern about the welfare of laying hens. (C) 2002 Elsevier Science B.V. All rights reserved.
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