2,043 research outputs found
Photograph of a bust of the author Tasma
No full textPhotograph of a bust of the author Tasma (Jessie Catherine Couvreur). Pencilled on verso of photo 'Tasma - enlargement of an original lent to H.M. Green? by Mrs Erdos, a neice of Tasma
Ontwikkeling in agrarische organisaties : organisatie-ontwikkeling in standorganisaties en cooperatieve verenigingen
No full textFarmers organizations, co-operatives and farmers unions, face changes in their organizational environment. Organization development is an effort to adapt and change the organization in order to meet environmental requirements in a purposeful way.For the study under review attention is paid to the decision-making processes on individual and organizational level.In chapter 1 a brief description is given of co-operatives and farmers unions in the Netherlands.The rationale to start a study on this topic is briefly pointed out.In chapter II is emphasized that the actual and futural situation in farmers organizations require the optimizing of decsision-making strategies.The focus of this thesis is an attempt to provide a descriptive theory of how organizations, groups and participating individuals can improve their decision making strategies.(We believe that the theoretical models presented in this book are applicable in a wider field, especially for the improvement of the decision-making process in organizations with a "voluntary" character (e.g. unions)).In chapter III a theoretical reflection is presented of the principles of planned-change. A clear justification of the chosen starting points is necessary to avoid misunderstandings and to attain theoretical progression. Our conclusion is that diverse perspectives should be distinguished depending on the particular stage of the planned-change process.The first stage, the fundamental theoretical anticipation when social change is conceived, should be described, assessed and analysed in such a way that the results are acceptable with reference to epistomelogical standards. (According to the views of Popper, Lakatos and Kuhn). For this reason a conceptual frame-work is presented in which diverse aspects of organization-sociology and psychology are integrated. The basic reasoning in this stage of scientific reflection has led to the choice of the following key-concepts: Activation (Etzioni), Mobilization (van Doorn), Participation (van Dyck), to be considered as prerequisites of social change.The second stage, the anticipation of social change in a specific situation (diagnosis), should be described and analysed not only in such a manner that the results are acceptable from a scientific point of view but that they also can meet ethical standards with regard to the consequences of the diagnosis for the welfare of individuals and the society as a whole.It is contended, that the above mentioned key-concepts do meet these requirements.The third stage, the social intervention in order to engender social changes, is to be conceived as an intersubjective-process. Enhancement of receptivity and communicative interaction between all involved subjects is most relevant in this stage.In chapter IV a description is given of the decision-making process on indiviudal level (Janis & Mann, Erikson and others). This description has led to a model of: "Stages in personal development with regard to participation in organizations with a voluntary character".The distinct, hierarchically ordered, stages are:- The search for trust (safety).- The cognitive orientation.- The identification with the organization in terms of personal involvement.- The awareness of mutually shared group interests.- The identification with organizational achievement.- The vigilant awareness and information processing with reference to thecommand and control stucture of the organization.- The identification with the organization as an "organizational-project"(ideological rooting).This "participation-model" can be utilized for many purposes: Analysis, diagnosis, intersubjective discussion and planning of change-programs.In chapter V strategic models for co-operatives and farmers unions are evaluated, in order to assess the most adequate approach for organizational development. In defining the focus, which seems most relevant for co-operatives, it is stressed that these organizations have to meet the requirements for "strategic flexibility".To clarify this point, the strategic position of co-operatives is further elaborated upon. The concepts, most applicable here are: management style, procedures for co-operation, and a characterization of the futural organizational environment. It is further asserted, that the same aspects may hold for farmers unions and in an analogous fashion attention should be paid to a strategic policy. In addition deliberate attempts should be made to improve the zeal for citizenship of the participating farmers, so as to enhance the exertion of "political power and influence" on regional, national and international levels.In chapter VI some generally accepted concepts of organization-development (Blake and Mouton, Hutte, Zwart, Beckhard and others) are discussed.This preatise has led to a development model for farmers organizations. The model is based on both insights derived from the literature on organizationdevelopment and expertised derived from personal experience with the actual functioning of farmers organizations.More in particular the model considers several successive stages in the organizational development:1. The entrance-phase.2. The first orientation at the meso-level of the organizational setting.3. The mobilization of local elected leaders.4. The follow-up of the mobilization of the local leaders.5. The integration of the outcome of the previous stages within the organizational structure.6. The second orientation aimed at problem solving regarding specific topics.7. The mandate for further development, on the basis of acquired skills.8. The "permanent" development: task-fulfilment in close co-operation with the board of the organization.We believe that the merit of the model is due to the implicated phasic developmental process based on the harmonious alternation of differentiation and integration.Finally in chapter VII some empirical data are presented. The empirical research took place at stage 3: "The mobilization of the local elected leaders".First an explorative description is given of the actual degree of activation and participation of the local elected leaders.Apart from the presentation of frequency distributions an explorative analysis was given by using factor-analysis of the questionnaire items, in order to determine whether mathematic transformation would coorroborate the theoretical conceptsas described in chapter IV. It was indeed shown that the factor structures found, are meaningful at the theoretical level.In the next stage was further explored whether the meaningful factors could be hierarchically ordered according to the sequence as presumed in chapter IV. Applying the Guttman-scale analysis it was indeed shown that an ordering of five theoretical meaningful factors could be ascertained.Some other findings are:1 . Local leaders show a strong activation of personal involvement (in the organization) with regard to the local community and also to recognizable problems (here and now problems).2. On the other hand a lower activation is shown with regard to less familiar complex problems such as: "the farmer and bio-industry", the workers-unions, and how to deal with "green" protest-groups.3. There is great interest in skills which are of importance in the sphere of vocational expertise.4. The local leaders consider their participation in the organization as a satisfactory psychological factor (entrance to information, respectable belonging to the community).5. The desire for organizational effectivity is as yet not translated in terms of "goal achievement-behavior" by the local leaders. (see chapter IV, stage 5). Implicating that the change of management skills is conceived as a bothersome affair.The second part of chapter VII presents the results of the empirical research based on the social intervention at the local level (see chapter VI, stage 3).The discrepancy between before- and after-measurements was tested with the t-test for dependent samples (two- tailed). It was shown for case-wise arranged paired observations that for the most part the differences between sample means turned out to be highly significant.By means of multiple-regression analysis was further explored which independent (or predictor) variables contribute to the most relevant changes.Some findings are:1. A significant progress is realized on the item of "organizational effectivity2. Changes most frequently occur if the local leaders are young, have more interest in the organization, or when their farm and land is more extensive.</p
Isogeometric analysis for multi-patch structured Kirchhoff–Love shells
No full textWe present an isogeometric method for Kirchhoff–Love shell analysis of shell structures with geometries composed of multiple patches and which possibly possess extraordinary vertices, i.e. vertices with a valency different to four. The proposed isogeometric shell discretisation is based on the one hand on the approximation of the mid-surface by a particular class of multi-patch surfaces, called analysis-suitable G1 (Collin et al., 2016), and on the other hand on the use of the globally C1-smooth isogeometric multi-patch spline space (Farahat et al., 2023). We use our developed technique within an isogeometric Kirchhoff–Love shell formulation (Kiendl et al., 2009) to study linear and non-linear shell problems on multi-patch structures. Thereby, the numerical results show the great potential of our method for efficient shell analysis of geometrically complex multi-patch structures which cannot be modelled without the use of extraordinary vertices.Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N. H.M. Verhelst is grateful for the funding from Delft University of Technology. J. Kiendl has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 864482). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée). Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N . H.M. Verhelst is grateful for the funding from Delft University of Technology . J. Kiendl has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 864482 ). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée).Numerical AnalysisShip Hydromechanics and Structure
Samuel H.M. Byers; Poet; Author; Diplomat; Oskaloosa; Iowa; Mahaska County; Iowa
No full textThis is a photograph taken of Samuel H.M. Byers at the onset of the Civil War in 1861. Byers served in the Union Army during the Civil War and gained a great deal of inspiration for his poetic writing during the war. Byers's most famous work is a poem entitled "Sherman's March to the Sea" recapping events that took place during this famous piece of American history. Byers is also credited with writing the state song of Iowa, played to the melody of "O, Christmas Tree". After gaining fame and fortune from his writing, Byers pursued a career in diplomacy, serving in the U.S. Consulate in Switzerland and Italy. Byers then came back to the U.S., living out the remainder of his days in Los Angeles, California. Byers died in 1933, at the age 95
Technical Efficiency in Crop Production: A Region-wise Analysis
No full textThe technical efficiency in crop production has been reported in different regions as well as in the state of Punjab to show how different regions have adopted the latest technology. Technical efficiency of individual farms has been estimated through stochastic frontier production function analysis. The production function estimates have pointed towards the presence of disguised unemployment in the sub-mountainous region of the Punjab state. The technical efficiency has shown a wide variation across regions. The average technical efficiency has been found maximum in the central region (90 per cent), followed by south-western and sub-mountainous regions. The main drivers of inefficiency have been identified as experience in agriculture and age of a farmer. The policy intervention to improve technical efficiency being not the same for all the regions, the study has observed that the state would benefit more if policy interventions are developed at the local level.Agricultural and Food Policy,
Isogeometric analysis of fluid cellular membranes: Application of discrete exterior calculus and isogeometric analysis to Stokes flow on time-evolving surfaces
No full textAn isogeometric finite element method for incompressible fluid film equations is presented. The method can be applied to numerically model the behaviour of thin cellular membranes, such as lipid bilayers. The membranes are represented by infinitely thin closed surfaces. Both the surface parametrization and analysis are based on state-of-the-art polar spline spaces. These spaces are defined such that a C1 continuous genus 0 surface can be constructed. At the discrete setting, point-wise conservation of mass is attained, using the framework of discrete exterior calculus. Therefore, the polar spline spaces are called divergence conforming. Time discretization of the highly non-linear system is done via the fixed-point iterations. It is found that for certain non-uniformly curved domains, the iterations converge and time stepping can be performed. However, for surfaces that are closely resembling a perfect sphere, the iterations are not stable for any ∆t. The solution is parameter-dependent and this indicates a possible bug in the Matlab code.Animation of the basic domain: https://youtu.be/YBrJwtOAqZ8 Gitlab project, containing the Matlab code that was used for this research: https://gitlab.tudelft.nl/hmverhelst/lipid-bilayersApplied Mathematic
A hierarchic isogeometric hyperelastic solid-shell
No full textThe present study aims to develop an original solid-like shell element for large deformation analysis of hyperelastic shell structures in the context of isogeometric analysis (IGA). The presented model includes a new variable to describe the thickness change of the shell and allows for the application of unmodified three-dimensional constitutive laws defined in curvilinear coordinate systems and the analysis of variable thickness shells. In this way, the thickness locking affecting standard solid-shell-like models is cured by enhancing the thickness strain by exploiting a hierarchical approach, allowing linear transversal strains. Furthermore, a patch-wise reduced integration scheme is adopted for computational efficiency reasons and to annihilate shear and membrane locking. In addition, the Mixed-Integration Point (MIP) format is extended to hyperelastic materials to improve the convergence behaviour, hence the efficiency, in Newton iterations. Using benchmark problems, it is shown that the proposed model is reliable and resolves locking issues that were present in the previously published isogeometric solid-shell formulations.Ship and Offshore StructuresNumerical Analysi
L'Image Du Buddha Dans L'Art Lao
No full textText and photos of Buddha images in LaosL'Image Du Buddha Dans L'Art Lao. Vientiane: H.M. Demain, 197
Towards a data assimilation system for morphodynamic modeling
No full textCurrently, available models are not able to accurately predict the temporal evolution of coastal morphodynamic processes. The main reason for this, is that essential components governing this evolution are neither fully identified nor understood. Additionally, there is high uncertainty in some of the parameterizations and their input parameters. A proper management of coastal systems depends on a thorough understanding of their present and future state. Regarding the present state of the system, detailed analyses that take into account the inference of human activities and interactions with other natural process may provide the required information to the decision makers. The evaluation of future states, on the other hand, is not possible without the use of data assimilation, i.e. integration of measurements and predictions in the context of formal uncertainty analysis. Despite the need to implement data assimilation, only recently the necessary coastal observations became available. Since then, the integration of data assimilation methods and coastal morphodynamic models have become the focus of ongoing research. Unfortunately, the implementation of these methods is not straightforward. Sequential data assimilation methods, such as ensemble Kalman filter, are practical to implement but their update usually breaks conservation laws and may easily result in model instabilities. Variational (adjoint based) schemes, on the other hand, preserve the physical integrity but require the implementation of an adjoint model which commonly matches in complexity the forward model. This thesis is concerned with the implementation of a variational data assimilation method to improve the predictive skills of a commercial model by estimating its input parameters. Model reduced 4DVar was used to address the problem. This method is an adjoint-free variational method that uses a truncated first order Taylor approximation of the morphodynamic model to implement the data assimilation process. The construction of the Taylor approximation is considerably simpler than the development of a full adjoint model. Additionally, the method provides the sensitivity of the morphodynamic model with respect to the state and/or input parameter vector. Regarding the commercial morphodynamic model, on the other hand, the Delft3D suite was selected. Delft3D is a module based simulator that merges a wave module and a flow and morphodynamic module to produce a fully coupled wave, flow and morphodynamic model. To gain a better understanding of the method and the potential challenges of its implementation on a real application, the technique is first applied to a small study case with synthetic observations (twin experiment). In this \emph{proof of concept}, three wave properties were estimated by assimilating observations of bathymetry. Different reduction strategies were implemented to characterize the method's performance and to assess the effects of uncertain observations on the results. The data assimilation method is able to improve the performance of the morphodynamic model and shows to be robust in the presence of noisy observations. Nevertheless, some difficulties are identified regarding the size and direction (sign) of the perturbations required for the finite difference estimations. In light of this finding, the implementation shows that it is necessary to increase the number of model executions to make the method more robust. Also, the test show problems in connection with the restarting capability of Delft3D. These problems have a significant impact on the accuracy of the finite difference estimations. To address the issues found in the proof of concept, an alternative novel model reduction method is proposed: \emph{ensemble model order reduction} (enMOR). The method computes the low rank linear approximation of the full model based on an ensemble similar to those used in Monte Carlo approaches (e.g. ensemble Kalman filter). This offers a number of advantages over the more common finite difference approach. For instance, the model executions necessary for this type of ensembles are not prone to numerical instabilities; making the implementation significantly more robust. The implementation time is considerably lower and the availability of such ensemble allows computing the model error covariance matrix, which was not available when the finite differences are used. Finally, the method does not requires the model to be restarted, solving altogether the problems identified during the implementation of this first experiment. The enMOR method was partially implemented in a more realistic study case based on a set of laboratory measurements. The measurements were taken as part of an experiment aimed at studying rip current circulations in a morphodynamic system. A set of 12 bathymetric observations were assimilated into the morphodynamic model to estimate a set of 19 flow, wave and morphodynamic parameters. One data assimilation problem for each state transition (LBT, RBB, TBR, and LTT) is implemented in order to characterize the parameter changes in each case independently. The enMOR technique is only applied to the dynamic components of the linear approximation, the model sensitivities to input parameters are estimated with finite differences. This serves two purposes, (1) it allows to assess possible shortcomings in the implementation of the method, and (2) reliable model sensitivities are estimated to analyze the influence of each parameter in the dynamic evolution of the system. The results show that the evolution of the morphodynamic system cannot be easily captured by a constant set of parameters; it is necessary to consider some of the parameters as time dependent. The results also show that the 2D model used is not able to reconstruct shallow and deep morphodynamic processes simultaneously. Nevertheless, the data assimilation is able to improve the overall performance of the model. The implementation of the enMOR shows no significant practical difficulty other than potential long estimation times for reduced order models of considerable size. A full implementation of the enMOR method with a 3D model of the Egmond aan Zee system in The Netherlands is finally presented. A set of time exposure images are used to estimate roller energy dissipation maps that are assimilated into the model to estimate a set of 13 input parameters that include the time-dependent wave height and peak period. The results show that the data assimilation method is able to find a parameter set that considerably improves the model performance. The results also suggest that the predicted morphodynamic evolution of the model has been improved, enhancing the forecasting capacity of the system. The implementation of the method proved significantly more practical than the common finite difference approach. The complete data assimilation implementation only required a set of 40 forward model runs (commonly known as ensemble). The model is not restarted at any point to produce the piece wise linear approximation necessary in model reduced 4DVar and no finite difference was implemented in the process. Consequently, the implementation difficulties observed in the proof of concept are not an issue in this implementation. In conclusion, enMOR is a practical model order reduction method that can be used for data assimilation without any loss of performance. Further developments are necessary to take advantage of the available information about the adjoint of the model. Its use in applications for observation network optimization and process characterization should be considered. Also, state estimation is probably the best manner for bathymetry estimation. On this regard, further research is necessary to assess the best manner to implement state estimation using model reduced 4DVar. Finally, an estimation of the expected errors of the reduced order models can be achieved by means of Monte Carlo methods. This information could be valuable to identify weaknesses in the reduced order model and therefore in the assimilation process.Applied mathematicsElectrical Engineering, Mathematics and Computer Scienc
Thermally-enhanced oil recovery from stranded fields: Synergy potential for geothermal and oil exploitation
No full textAccepted author manuscriptReservoir EngineeringApplied Geolog
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