From the article: Abstract Adjustment and testing of a combination of stochastic and nonstochastic observations is applied to the deformation analysis of a time series of 3D coordinates. Nonstochastic observations are constant values that are treated as if they were observations. They are used to formulate constraints on the unknown parameters of the adjustment problem. Thus they describe deformation patterns. If deformation is absent, the epochs of the time series are supposed to be related via affine, similarity or congruence transformations. S-basis invariant testing of deformation patterns is treated. The model is experimentally validated by showing the procedure for a point set of 3D coordinates, determined from total station measurements during five epochs. The modelling of two patterns, the movement of just one point in several epochs, and of several points, is shown. Full, rank deficient covariance matrices of the 3D coordinates, resulting from free network adjustments of the total station measurements of each epoch, are used in the analysis.
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In this post I give an overview of the theory, tools, frameworks and best practices I have found until now around the testing (and debugging) of machine learning applications. I will start by giving an overview of the specificities of testing machine learning applications.
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In the literature about web survey methodology, significant e orts have been made to understand the role of time-invariant factors (e.g. gender, education and marital status) in (non-)response mechanisms. Time-invariant factors alone, however, cannot account for most variations in (non-)responses, especially fluctuations of response rates over time. This observation inspires us to investigate the counterpart of time-invariant factors, namely time-varying factors and the potential role they play in web survey (non-)response. Specifically, we study the effects of time, weather and societal trends (derived from Google Trends data) on the daily (non-)response patterns of the 2016 and 2017 Dutch Health Surveys. Using discrete-time survival analysis, we find, among others, that weekends, holidays, pleasant weather, disease outbreaks and terrorism salience are associated with fewer responses. Furthermore, we show that using these variables alone achieves satisfactory prediction accuracy of both daily and cumulative response rates when the trained model is applied to future unseen data. This approach has the further benefit of requiring only non-personal contextual information and thus involving no privacy issues. We discuss the implications of the study for survey research and data collection.
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With summaries in Dutch, Esperanto and English. DOI: 10.4233/uuid:d7132920-346e-47c6-b754-00dc5672b437 "The subject of this study is deformation analysis of the earth's surface (or part of it) and spatial objects on, above or below it. Such analyses are needed in many domains of society. Geodetic deformation analysis uses various types of geodetic measurements to substantiate statements about changes in geometric positions.Professional practice, e.g. in the Netherlands, regularly applies methods for geodetic deformation analysis that have shortcomings, e.g. because the methods apply substandard analysis models or defective testing methods. These shortcomings hamper communication about the results of deformation analyses with the various parties involved. To improve communication solid analysis models and a common language have to be used, which requires standardisation.Operational demands for geodetic deformation analysis are the reason to formulate in this study seven characteristic elements that a solid analysis model needs to possess. Such a model can handle time series of several epochs. It analyses only size and form, not position and orientation of the reference system; and datum points may be under influence of deformation. The geodetic and physical models are combined in one adjustment model. Full use is made of available stochastic information. Statistical testing and computation of minimal detectable deformations is incorporated. Solution methods can handle rank deficient matrices (both model matrix and cofactor matrix). And, finally, a search for the best hypothesis/model is implemented. Because a geodetic deformation analysis model with all seven elements does not exist, this study develops such a model.For effective standardisation geodetic deformation analysis models need: practical key performance indicators; a clear procedure for using the model; and the possibility to graphically visualise the estimated deformations."
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Author supplied: "This paper gives a linearised adjustment model for the affine, similarity and congruence transformations in 3D that is easily extendable with other parameters to describe deformations. The model considers all coordinates stochastic. Full positive semi-definite covariance matrices and correlation between epochs can be handled. The determination of transformation parameters between two or more coordinate sets, determined by geodetic monitoring measurements, can be handled as a least squares adjustment problem. It can be solved without linearisation of the functional model, if it concerns an affine, similarity or congruence transformation in one-, two- or three-dimensional space. If the functional model describes more than such a transformation, it is hardly ever possible to find a direct solution for the transformation parameters. Linearisation of the functional model and applying least squares formulas is then an appropriate mode of working. The adjustment model is given as a model of observation equations with constraints on the parameters. The starting point is the affine transformation, whose parameters are constrained to get the parameters of the similarity or congruence transformation. In this way the use of Euler angles is avoided. Because the model is linearised, iteration is necessary to get the final solution. In each iteration step approximate coordinates are necessary that fulfil the constraints. For the affine transformation it is easy to get approximate coordinates. For the similarity and congruence transformation the approximate coordinates have to comply to constraints. To achieve this, use is made of the singular value decomposition of the rotation matrix. To show the effectiveness of the proposed adjustment model total station measurements in two epochs of monitored buildings are analysed. Coordinate sets with full, rank deficient covariance matrices are determined from the measurements and adjusted with the proposed model. Testing the adjustment for deformations results in detection of the simulated deformations."
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The global agenda to move societies towards a more sustainable course of development also affects the lives of older people in our ageing populations. Therefore, it is important to understand the drivers, intentions and behaviours concerning sustainability among older adults. The aim of this study is to translate and cross-culturally validate an existing instrument (SustainABLE-16 Questionnaire), developed in the Netherlands, which measures how older people view the theme of environmental sustainability in their daily lives, for use in Romania, Poland, North Macedonia and Israel. The SustainABLE-16 covers three domains: 1) Pro-environmental behaviours; 2) Financial position; and 3) Beliefs. The scale was translated in Romanian, Polish, Macedonian, Albanian and Hebrew. Its 16 items were appraised for relevance by older people and experts in the field. A total of 2299 older people, including the original Dutch respondents, were included for the assessment of the level of measurement invariance across six languages, spoken in five countries. As the initial validation of the SustainABLE-16 did not meet internationally-recognised fit requirements, the shorter SustainABLE-8 was validated instead. This instrument proved valid for use in all participating countries (configural validity). Subsequently, increasingly constrained structural equation models were applied to test their fit with the data, ensuring that the fit did not deteriorate. The test results of measurement invariance across the countries indicated that items were stable, achieving partial scalar invariance, with five items demonstrating full scalar invariance. The shorter SustainABLE-8 functions uniformly across all language groups and can, therefore, be used to evaluate sustainable practices among older people. A better understanding of the drivers and practices among older citizens across Europe could, in turn, feed into more fitting public policies on sustainability in the built environment.
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De invoering van de bachelor-masterstructuur was aanleiding voor de HBO-I stichting, het samenwerkingsverband van hbo ict-opleidingen in Nederland, om de oude opleidings- en beroepsprofielen (2000) aan te passen aan de nieuwe ontwikkelingen in het Europese hoger onderwijs. In nauwe samenwerking met het bedrijfsleven heeft de HBO-I stichting vijftien bouwstenen voor competenties geformuleerd. Deze vormen de basis van de competenties die een pas afgestudeerde Bachelor of ICT, ook in internationaal perspectief, dient te bezitten. Competenties krijgen betekenis in een context. Daarom staat in het profiel een aantal karakteristieke in rekle beroepssituaties beschreven waar een pas afgestudeerde Bachelor of ICT daadwerkelijk in de praktijk mee te maken kan krijgen. De context waarin een Bachelor of ICT fungeert, bepaalt het individuele competentieprofiel. De context bepaalt tevens het niveau waarop de afgestudeerde Bachelor of ICT over de specifieke beroepscompetenties dient te beschikken. Het ict-domein is zeer breed. De nieuwe profielbeschrijving biedt ruimte aan hogescholen om specifieke invulling te geven aan hun onderwijsprogramma s die studenten opleiden tot Bachelor of ICT. Bij het (her)ontwerpen van deze onderwijsprogramma s kunnen de bouwstenen voor competenties uitstekend dienst doen. Het is aan de instelling om een specifieke invulling te geven aan een opleidingsprogramma dat de beschreven bouwstenen voor competenties omvat. Het profiel is ook een referentiekader voor de arbeidsmarkt om zicht te krijgen op wat iemand met die graad in huis heeft. En het is tevens een referentiekader voor aankomende studenten, schooldecanen en beroeps- en studiekeuzeadviseurs om gevoel te krijgen voor het werkveld van ict ers en voor de onderwijswegen daar naartoe. Binnen het nieuwe profiel van de Bachelor of ICT blijven bestaande ict-opleidingen als beroepsprofielen herkenbaar. Ook andere opleidingen leiden op tot Bachelor of ICT. Naast de bekende profielen kunnen in de toekomst andere opleidingsvarianten ontstaan. Voor al deze varianten, bestaand of toekomstig, vervullen de bouwstenen voor competenties de rol van een generieke profielbeschrijving. De opzet van het competentieprofiel is zodanig dat er uitdrukkelijk ruimte is voor opleidingen in individuele studenten om een breder opleidingsprofiel te kiezen. Daarmee is de nieuwe profielbeschrijving voorbereid op het ontstaan van een zogenaamde brede bachelor of ICT.
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This paper describes the concept of a new algorithm to control an Unmanned Aerial System (UAS) for accurate autonomous indoor flight. Inside a greenhouse, Global Positioning System (GPS) signals are not reliable and not accurate enough. As an alternative, Ultra Wide Band (UWB) is used for localization. The noise is compensated by combining the UWB with the delta position signal from a novel optical flow algorithm through a Kalman Filter (KF). The end result is an accurate and stable position signal with low noise and low drift.
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Deze publicatie is uitgebracht ter gelegenheid van de rede uitgesproken op 21 september 2022 bij de installatie van Dr. Rix Groenboom als lector New Business & ICT bij het lectoraat Digitale Transformatie.
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Het veranderende klimaat is vooral in binnensteden zichtbaar door de hoge mate van verstening die hier te vinden is. Juist op deze plekken zijn er weinig oplossingen voor hittestress en wateroverlast mogelijk, omdat de ruimte boven en onder de grond vaak beperkt is. In dit onderzoek werkten de Hanzehogeschool en The Leaf vof in een consortium met ondernemers en publieke organisaties aan het ontwikkelen van een oplossing voor deze problemen: de Leaf. Een ‘Leaf’ is een groene pergola die meerdere thema’s als hittestress, wateroverlast, biodiversiteit en circulariteit combineert in één oplossing. Het primaire doel van dit onderzoek was om de effectiviteit, haalbaarheid en rendabiliteit van een Leaf in de praktijk te toetsen. Daarvoor is een design thinking aanpak gevolgd, waarin verschillende methoden zijn gebruikt om onderzoeks- en ontwerpstappen te doorlopen. De uiteindelijke ontwerpen zijn uitgewerkt in fysieke prototypes met verschillende karakteristieken die vervolgens op hun effectiviteit zijn getest en vergeleken. Het onderzoek is met een interdisciplinair team van studenten en onderzoekers uitgevoerd, met ondersteuning van verschillende experts uit de praktijk.
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