61 research outputs found
Pitting corrosion of stainless steels: The role of inclusions and the effect of surface deformation
No full textMechanical Maritime and Materials Engineerin
Economic Complex Networks: A holarchy of evolving sector
No full textThis thesis aims to contribute to the understanding of the structure, composition, properties, functions and dynamics of economic systems. The research output results from joining advances in the scientific disciplines of systems theory, complex networks, Input-Output analysis and economic activity classification systems. The relevance of this research primarily lies in the insight and overview that arose from bridging these disciplines. The central theme in this research is the complex network of economic sectors in which the transactions between sectors determine the dynamic structure of an economic network. A sector network is an abstract aggregate of sectors. When observed in more detail, the network structure of an economic system becomes visible between sub-sectors and their constituent parts (revealing organisations and individuals at most detailed level). In this thesis, this hierarchy is also referred to as a holarchy. Sectors can be analysed from various perspectives such as activities (functions), products (services and/or goods), organisations (enterprises), occupations (crafts of individuals) and production means (tools). For instance, financing is an activity, a loan is a product, a bank is an organisation and a banker is an occupation. Sector names such as finance sector or banking sector are commonly used which illustrates the difficulties in establishing a set of non-ambiguous sector names and definitions. In daily practice the above mentioned perspectives tend to be mixed up and (overlapping) thematic aggregates are defined as sectors (e.g. creative sector, technology sector), complicating the production of statistical compilations. This mixed perspective approach ignores classification principles such as completeness, summability, exclusiveness and categorising from one perspective, based on the criterion of homogeneity. The perspective of activities or functions emphasised in this thesis, is also expressed in the design of a novel sector model and sector network model. The functional analysis of sector related activities (sourced from the UN economic activity classification system (ISIC) and a set of standards and models specific to the telecom related sector) shows that only 3% of the inventoried functions of a sector was found unique on average. This finding is in line with propositions from system theory. Prominently included in this thesis are the representation of economic systems as complex networks and the accompanying analysis of German and Dutch Input-Output data. This analysis of the monetary flows in the German and Dutch economic networks shows a full-mesh structure at sector level, thus each sector can directly share produced (unique) value with every other sector. Supported by findings from literature review, a contemporary sector network appears to consist of twenty complementary economic sectors. When descending the hierarchy below the sector level, the link density decreases, thus not all sub-sectors are directly connected. Observations from the analysis of the Input-Output data (1987-2007) show an increasing network clustering coefficient and a decreasing value of the interaction ratio of the sector network over time. Furthermore organisation fragmentation is observed from Dutch statistics about the composition of enterprises (2001-2012). Possibly these indicators directly relate to the increasing scale of outsour-cing activities and the governmental policy of privatisation and the dismantling of monopolies in order to stimulate competition. This observation and interpretation show that network analysis generates interesting questions and hypotheses, which could enrich economic science. The above mentioned economic phenomena and the recent economic crises, raise the question if the sector network can be safely exposed to market forces. This thesis pleads for a more intensive orchestration of the sector network as a whole and the functioning of our vital sectors in particular.INSY NASElectrical Engineering, Mathematics and Computer Scienc
Telecom and Energy, vital sectors enabling Smart Living
No full textThis thesis investigates the past, present and future of energy, telecom and household related developments aiming to pinpoint synergetic innovation possibilities. Providing overview and insights at the aggregation level above, being the sector network, is the first necessary step to reach this goal. The academic part of this thesis focuses on the sector network. Statistics Netherlands provided two data sets: the Working People and Monetary transactions. These data sets reflect a part of the monetary sector network evolution over the last two decades. In this research, we analysed these data sets from a complex network perspective and visualised as a real world network. Next, the data sets were related to the list of vital sectors of the Dutch Ministry of Interior Affairs to observe and understand trends and dependencies among these sectors. This research shows that the Household is the prime and most highly connected node within the sector network closely flanked by Telecom and Energy. The practical part of the thesis focuses on the vital sectors, their infrastructures, the major trends and the added value resulting from their collaboration. A trend analysis of the ICT developments related to the household in 2000, 2010 and expectations of 2020 are examined by means of expert interviews. Combining innovation options related to Energy, Telecom, Healthcare and Household reveal viable, sustainable near future trans-sector solutions. The importance of the information communication value added to Smart Grids is clearly demonstrated. Finally, the development of devices within the home is studied to find out which sectors already have traces in home and which effects would be expected for the telecom sector.Trans-sector Innovation TeamNetwork Architectures & Services (NAS)Electrical Engineering, Mathematics and Computer Scienc
Data-driven 3D Deghosting Using Multisensor Marine Measurements
No full textMarine seismic acquisition tows submerged streamers to record pressure waves from the subsurface. The recording, however, contains both the desired upgoing wavefield and its (immediate) reflection off the sea-surface, causing a downgoing wavefield known as the seismic ghost. Interference between the up- and downgoing waves causes periodic low signal to noise ratio (S/N) ‘ghost notches’ in the recorded spectrum. To restore the broadband upgoing signal, we must remove the ghost (‘deghosting’). Deghosting using solely pressure measurements fails to restore the signal in the low S/N notches of the data. Current acquisition techniques acquire signals with different ghost notches, such that their proper combination recovers the broadband signal. This thesis uses multisensor acquisition: measurements of the pressure and particle velocity vector. The ghost notches on the pressure and vertical particle velocity are offset by half a period, such that their combination may provide good S/N at all frequencies. Current multisensor deghosting techniques make deterministic assumptions on the data and ghost model (such as a known streamer depth, or assuming energy propagating only along the streamer). If the assumptions do not correspond to the data, the deghosting fails to restore the true broadband signal. We propose two novel data-driven deghosting techniques, which estimate an adequate deghosting filter based on the data itself. The first method estimates the 3D propagation of energy using measurements of the pressure and crossline particle velocity along a single streamer. The 3D incidence angle is used to sum the pressure wave with vertical particle velocity such that only the upgoing wave is recovered. The second method estimates the filter parameters that explain the recorded ghosted data by minimizing a multisensor least-squares deghosting cost function. The cost function is analytically shown to outperform similar single sensor adaptive deghosting techniques in terms of sensitivity to the true ghost model. The obtained filter parameters may then be used to construct an inverse filter that restores the upgoing wavefield. We found that both methods produce encouraging results on real data, outperforming the existing deterministic multisensor deghosting methods.Civil Engineering and GeosciencesGeoscience & EngineeringApplied Geophysic
Duurzaamheid als Aanbestedingscriterium bij Haveninvesteringen
No full textMany industries are already aware of the fact that they can gain higher profits by integrating sustainability within their management process. The construction industry seems to be a late developer. Lately, port authorities have started many initiatives for a more sustainable port. To make ports more sustainable it is worthwhile to improve the construction of infrastructure and building projects: the construction industry is still one of the most polluting industries. Hence, in this thesis the answer is given to the question of how to integrate sustainability as a procurement criterion for infrastructure projects in ports. This is done by developing a procurement model which is aimed at sustainable procurement. Sustainability is important for a port: the amount of total environmental space is decreasing due to stricter policies. To enable further growth of port activities, sustainable management is inevitable. A more sustainable port results in a larger public support for port activities. Furthermore, sustainable management can result in lower costs due to a higher efficiency in the business activities. It is important that the port authority chooses for a contracting form that allows enough space for the contractor to deliver a sustainable construction. This is possible with innovative contracting forms such as D&B contracts in contrast to traditional contracting forms. The right procurement procedure is important too. The model includes criteria and an evaluation method. These criteria are set based on interviews with stakeholders and literature search. These criteria can be categorized in the fields People, Planet and Profit. It is essential to apply Life Cycle Analyses with a preference for quantification of criteria e.g. emission footprints. In practice this is almost impossible due to the complex computations which contractors have to do. That is why the applied model is different from the ideal model, because there is chosen to assess the different measures in a qualitative way on 1) how specific, measurable, acceptable, realistic and time bounded the measures are and on 2) the impact during the whole Life Cycle of the construction. It is important that it is clear for the contractor which criteria are used and what is demanded by the assessment of the measures on sustainability. The alternatives are evaluated with the concordance method. This method is emerged as the most suitable based on applicability, transparency, flexibility, stability, effectiveness and user-friendliness. Beside it evaluates the scoring on weighted criteria (concordance), the concordance method evaluates how low the alternative scores for a good balance between the criteria. This is how this method distinguishes itself in a positive way. The criteria with the evaluation method form the model and it is applied on three different projects for the construction of quay walls in the port of Rotterdam. There was a clear differentiation between the alternatives in the outcomes, in an appraisal was made between sustainable criteria and investment costs. The model is applicable in different phases in the tender process. The scores on concordance and discordance give extra information about the foundations of the outcomes of the tender, which is an advantage of the method.Hydraulic EngineeringCivil Engineering and Geoscience
Telecom Sector Modelling from a Functional Perspective
No full textToday’s Telecom sectors’ implementations seem to be sub optimal and might even end up out of control because of the multiple implementation of technological and process functionalities, and dominant financial focus that complicates removing legacy networks. Even though, there is support for fulfilling customer needs, the inefficient use of resources can negatively affect the business activities and profits. The Telecom sectors’ current evolutionary stage requires a thorough evaluation of all its current implementations in order to restructure and consolidate them. In order to maintain the vital telecom contribution to our society and economy, cost optimisations and the ability to keep on innovating in an increasing complex setting, need to be safeguarded. We know that, apart from financial difficulties, there are important handicaps in this sector itself: it has an ill-defined set of functions that has been addressed by different standardisation bodies. This has led to the main research question, namely: How to identify a best of breed model which both reflects the current (2009) and the near future (2012) Telecom sector functionality in order to come up with an advise about optimising its internal functional structure taking into account the relevant requirements concerning interoperability with other sectors? The major objective of this study was to identify both the internal and external functions performed by the Telecom sector and thus reveal how they provide value to the other nodes in the sectors’ network. The Telecom sector (as defined in this document) is the research domain and subject of modelling in this thesis. Accordingly, the functional approach deliberately chosen for this project provides an implementation independent basis of knowledge that could be transferrable from the Telecom sector to other sectors or to different aggregation levels in the economy and society. The functions were extracted from well known and commonly used telecom related models. As a result, from the data mining and analysis applied to those telecom related models, this thesis provides a long list of 331 functions performed by the Telecom sector. In addition, these functions were mapped onto other non-telecom sector specific models that have a sectors’ network applicability in order to confirm the neutrality of the functional perspective. A minority of those functions proved to be Telecom sector specific. In this thesis, we present a proposition to classify functions, taking into account two dimensions: Composition (atomic, composed), and domain of applicability (generic, specific). It is known that the generic-specific dimension has been considered before; however, in this thesis we have included a new dimension atomic-composed. These both dimensions are not exclusively, can be applied at the same time, and are context dependant. One of the models studied in this study, providing a sectors’ network view is the Holon model. This model as well makes use of the fact that natural language can be used to represent the economic and social context. It has three main propositions: 1. Holons could be considered as nodes in a network 2. A holon is composed of four layers: est, vivit, sensit, intelligit 3. Each holon can interact with other holons in their same aggregation level (left & right), not only with the holons in other levels of the hierarchy/holarchy (up & down) Interaction with other holons in the same aggregation level is a proposition presented in this thesis. The original concept of holon (proposed by Arthur Koestler) implies that holons form a hierarchical structure (called holarchy), keeping relations with other holons in upper and lower levels of the hierarchy it is part of. This thesis includes as well, an application of graph theory to get insights about the set of data obtained. In this direction, we identified the most common functions in between all the models assessed by doing an exercise of a graph representation. Furthermore, after studying functions and the Holon concept, we propose some new questions for the complex networks and graph theory community: 1. Going from nodes to holons 2. Consider holons being four-tiered structures. 3. Holons looking up and down to other aggregation levels, but also looking left & right within its own aggregation level. From two-tiered graphs to four tiered graphs, the est layer being the foundation of three overlays: vivit, sensit, intelligit. Currently, the flows that traverse the envisaged sensit and intelligit layer are performed by human beings. In the Telecom sector the est and vivit layer are mainly performed by systems. 4. To open a holon and look inside them, how their internal behaviour is reflected to other nodes in the network/hierarchy. Opening a holon shows another four tiered network. The research methodology described in this thesis proved to be suitable to obtain a functional model. The answer to this “how” question was given via the following steps: 1. Selecting sector specific standards and models based on the proposed criteria 2. Extracting functions from those models and long-listing them (functional portfolio) 3. Mapping functions to generic (non-telecom sector specific) model (testing) We have obtained a list of functions that was mapped to three selected generic models (STOF, CTOM, Holon) and to the meta-functions (that are common to all sectors). This led to the conclusion that it is possible to derive a novel functional model from the existing models, if we have a focus on a specific target (in our case: to serve the sectors network). The best of breed model we have chosen is based on the Holon concept explained above.TelecommunicationsElectrical Engineering, Mathematics and Computer Scienc
Community Detection for Temporal Weighted Bipartite Networks
No full textCommunity detection of temporal (time-evolving) bipartite networks is challenging because it can be performed either on the temporal bipartite network, or on various projected networks, composed of only one type of nodes, via diverse community detection algorithms. In this paper, we aim to systematically design detection methods addressing both network choices and community detection algorithms, and to compare the community structures detected by different methods. We illustrate our methodology by using a telecommunications network as an example. We find that three methods proposed identify evident community structures: one is performed on each snapshot of the temporal network, and the other two, in temporal projections. We characterise the community structures detected by each method by an evaluation network in which the nodes are the services of the telecommunications network, and the weight of the links between them are the number of snapshots that both services were assigned to the same community. Analysing the evaluation networks of the three methods reveals the similarity and difference among these methods in identifying common node pairs or groups of nodes that often belong to the same community. We find that the two methods that are based on the same projected network identify consistent community structures, whereas the method based on the original temporal bipartite network complements this vision of the community structure. Moreover, we found a non-trivial number of node pairs that belong consistently to the same community in all the methods applied.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Multimedia ComputingNetwork Architectures and Service
The beneficial local and abscopal effect of splenic irradiation in frail patients with chronic lymphocytic leukaemia
No full textBiological, physical and clinical aspects of cancer treatment with ionising radiatio
Psychological distress among lymphoma survivors:From inventory to intervention
No full textPsychological distress among lymphoma survivors – from inventory to intervention Dit proefschrift beschrijft het proces van het inventariseren van factoren die samenhangen met psychologische stress bij (ex-)patiënten met lymfeklierkanker tot de ontwikkeling en evaluatie van een interventie die gericht is op het vergroten van de zelfmanagementvaardigheden, tevredenheid van informatievoorziening, en het verminderen van psychische stress. Het eerste deel van dit proefschrift bestaat uit een inventarisatie van factoren die samenhangen met psychologische stress bij (ex-)patiënten met lymfeklierkanker. Een jongere leeftijd en de aanwezigheid van comorbiditeit(en), zoals diabetes en cardiovasculaire ziekten, hangen samen met meer psychische stress. Ook persoonlijkheid en omgangsstijlen zijn gerelateerd aan psychologische stress. Zo ervaren mensen die hoog scoren op neuroticisme meer psychische stress, maar ook mensen die hoog scoren op specifieke omgangsstijlen, zoals hulpeloosheid en angstige preoccupatie. Tevens werd gevonden dat (ex-)patiënten met lymfeklierkanker vaker naar de huisarts en/of medisch specialist gaan in vergelijking met personen uit een normatieve populatie zonder kanker. Bezoeken aan de medisch specialist kunnen voortduren tot meer dan tien jaar na diagnose. Ook werden verschillen gevonden tussen (ex-)patiënten met en zonder psychische stress. Patiënten met psychische stress maakten niet alleen meer gebruik van medische zorg, maar ontvingen ook meer psychosociale zorg. Meer dan de helft van de patiënten met psychische stress kreeg géén psychosociale zorg. Vooral onder oudere (ex-)patiënten is de psychosociale zorg niet optimaal. In het tweede deel van het proefschrift wordt de ontwikkeling en evaluatie van een online interventie – Lymphoma InterVEntion [LIVE] – beschreven, gericht op het bevorderen van zelfmanagementvaardigheden en tevredenheid met de informatievoorziening en het verminderen van psychologische stress. LIVE bestaat uit twee interventies: 1) tot terugkoppeling van patiëntgerapporteerde uitkomsten en 2) een online zelfhulpinterventie ‘Leven met lymfeklierkanker’. De deelnemers bestonden uit patiënten met lymfeklierkanker uit verschillende ziekenhuizen in Nederland. Zij werden gerandomiseerd in een van de drie studiearmen: 1) gebruikelijke zorg, 2) gebruikelijke zorg plus toegang tot terugkoppeling van patiëntgerapporteerde uitkomsten en 3) gebruikelijke zorg plus toegang tot terugkoppeling van patiëntgerapporteerde uitkomsten én deelname aan de online interventie ‘Leven met lymfeklierkanker’. Deelnemers vulden vragenlijst in via PROFIEL, een patiëntenvolgsysteem dat IKNL in samenwerking met Tilburg University heeft ontwikkeld, waarmee patiëntgerapporteerde uitkomsten kunnen worden gekoppeld aan klinische gegevens uit de Nederlandse Kankerregistratie (NKR). Uit de resultaten van de LIVE-studie blijkt dat terugkoppeling van patiëntgerapporteerde uitkomsten geen effect heeft op psychische stress, zelfmanagementvaardigheden, tevredenheid met de informatievoorziening en zorggebruik. Ook had het terugkoppelen van patiëntgerapporteerde uitkomsten geen negatieve invloed op het welzijn van patiënten met lymfeklierkanker. De terugkoppeling van patiëntgerapporteerde uitkomsten werd door 77% van de patiënten bekeken en komt tegemoet aan de wensen van patiënten om beter inzicht te krijgen in hun eigen patiëntgerapporteerde uitkomsten. Het gebruik van de online zelfhulpinterventie ‘Leven met lymfeklierkanker’ lag veel lager. Slechts 36% van de patiënten die toegang hadden tot de interventie, meldde zich hiervoor aan en 16 patiënten hebben tenminste een onderdeel van de interventie geopend. Vanwege het geringe gebruik van de interventie kunnen nog geen sluitende conclusies worden getrokken over de effecten van ‘Leven met lymfeklierkanker’ op psychische stress, zelfmanagementvaardigheden, tevredenheid met de informatievoorziening en zorggebruik. Van het totaal aantal geselecteerde patiënten met lymfeklierkanker (1.193), kregen 892 patiënten (75%) een uitnodiging voor deelname aan de studie. Hiervan vulden 227 patiënten (25%) de vragenlijst online in en namen deel aan de gerandomiseerde studie. Deze patiënten waren jonger, vaker man en hoger opgeleid dan mensen die de vragenlijst op papier of helemaal niet invulden en dus niet deelnamen aan de gerandomiseerde studie. Ouderen, vrouwen en lager opgeleide patiënten waren onvoldoende vertegenwoordigd in de LIVE-studie, wat de generaliseerbaarheid van de resultaten beperkt. Ook is meer onderzoek nodig naar de achterliggende oorzaken waarom sommige patiënten niet worden bereikt en wat de beste manier is om het bereik van de online interventie te verbeteren. Implementatie van de online zelfhulpinterventie ‘Leven met lymfeklierkanker’ in de dagelijkse, klinische praktijk wordt daarom (nog) ontraden. Terugkoppeling van patiëntgerapporteerde uitkomsten kan wél worden geïmplementeerd in de klinische praktijk, omdat deze duidelijk tegemoet komt aan de wensen van patiënten zonder dat het de zorgen en angsten over de ziekte lijkt te vergroten.<br/
Node Survivability and Dynamics of the Dutch Municipality Network
No full textThis thesis’ research concerns the time-dynamics of a complex geographical network of municipalities, i.e. the Dutch Municipality Network over the period 1830-2019. By analysing 190 years of socioeconomic statistical data and applying contemporary tooling from network science and geographic information systems (GIS), the findings from this research can provide a new approach and supportive methods for policymakers, statistical offices, researchers and businesses (to decide when and where to invest).Computer Science | Data Science and Technolog
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