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University of Twente Publications (59.230 recursos)

University of Twente Repository provides publications of UT scientific staff, in many cases full text and publicly available.

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Mostrando recursos 1 - 20 de 27.274

  1. Capacity evaluation of multi-lane traffic roundabout

    Bie, Jing; Lo, Hong K.; Wong, S.C.
    The entry capacity at a traffic roundabout is typically evaluated for each entry approach, considering the circulating flow and geometric characteristics, e.g., the US highway capacity manual model and the UK Linear Regression model. These models are not appropriate for analyzing multi-lane roundabouts because they do not take into account the possible unequal traffic distribution between the circulating lanes. This paper introduces a lane-based methodology that evaluates the entry capacity for each individual lane while considering the traffic distribution on the circulating lanes. The arrival and circulating flows are formulated based on drivers' lane choice patterns. We then modify and...

  2. Inkoopmanagement met cijfers

    Telgen, J.; Cobben-Mulder, M.
    Managers moeten geïnformeerd prioriteiten kunnen leggen bij verbeteracties in de inkoopfunctie. Een (inkoop)manager moet kunnen bepalen welke inkooppakketten centraal, gecoördineerd of decentraal moet worden aanbesteed, of een afgesloten raamovereenkomst wel voldoende wordt benut en of e-procurement leidt tot kostenreductie. Om gericht te kunnen sturen is inzicht nodig in de prestaties van de inkoopfunctie. De beschikbaarheid van kwantitatieve informatie (ofwel cijfermatig inzicht) is daarbij essentieel. Inkoopinformatie is niet alleen interessant voor inkoopmanagers. Managers op andere gebieden en budgethouders zijn evenzeer gebaat bij het beschikbaar komen van deze informatie. De cijfers helpen het management namelijk bij het nemen van beslissingen op het gebied...

  3. Ontology-based high-level context inference for human behavior identification

    Villalonga, Claudia; Razzaq, Muhammad Asif; Ali Khan, Wajahat; Pomares, Hector; Rojas, Ignacio; Lee, Sungyoung; Banos, Oresti
    Recent years have witnessed a huge progress in the utomatic identification of individual primitives of human behavior, such as activities or locations. However, the complex nature of human behavior demands more abstract contextual information for its analysis. This work presents an ontology-based method that combines low-level primitives of behavior, namely activity, locations and emotions, unprecedented to date, to intelligently derive more meaningful high-level context information. The paper contributes with a new open ontology describing both low-level and high-level context information, as well as their relationships. Furthermore, a framework building on the developed ontology and reasoning models is presented and evaluated....

  4. Efficient implementation of Carathéodory’s theorem for the single machine scheduling polytope

    Hoeksma, Ruben; Manthey, Bodo; Uetz, Marc
    In a fundamental paper in polyhedral combinatorics, Queyranne describes the complete facial structure of a classical object in combinatorial optimization, the single machine scheduling polytope. In the same paper, he answers essentially all relevant algorithmic questions with respect to optimization and separation. In the present paper, motivated by recent applications in the design of optimal incentive compatible mechanisms, we address an algorithmic question that was apparently not addressed before. Namely, we turn Carathéodory’s theorem into an algorithm, and ask to write an arbitrary point in the scheduling polytope as a convex combination of the vertices of the polytope. We give...

  5. Head-to-head comparison of anti-inflammatory performance of known natural products In Vitro

    Allijn, Iris E.; Vaessen, Stefan F.C.; Quarles van Ufford, Linda C.; Beukelman, Kees J.; Winther, Menno P.J. de; Storm, Gert; Schiffelers, R.M.
    Inflammation is an important therapeutic target. Due to their potency, steroidal drugs dominate the current treatment of inflammatory disorders. However, steroidal drugs can also exert a broad range of side effects and appear not always effective. This calls for the development of alternative drugs with a different mechanism of action, which are likely to be found in the field of natural products (NPs). For many NPs strong anti-inflammatory effects have been described, but usually investigating a single compound in a single assay. In this study, eight promising NPs were selected and tested against the strong anti-inflammatory drug prednisolone. For this...

  6. Comparison of pharmaceutical nanoformulations for curcumin: enhancement of aqueous solubility and carrier retention

    Allijn, Iris E.; Schiffelers, R.M.; Storm, Gert
    Curcumin, originally used in traditional medicine and as a spice, is one of the most studied and most popular natural products of the past decade. It has been described to be an effective anti-inflammatory and anti-cancer drug and protects against chronic diseases such as rheumatoid arthritis and atherosclerosis. Despite these promising pharmacological properties, curcumin is also very lipophilic, which makes its formulation challenging. Ideally the nanocarrier should additionally also retain the encapsulated curcumin to provide target tissue accumulation. In this study we aimed to tackle this aqueous solubility and carrier retention challenge of curcumin by encapsulating curcumin in different nanoparticles. We successfully loaded...

  7. Bacteria Delay the Jamming of Particles at Microchannel Bottlenecks

    Sendekie, Zenamarkos Bantie; Gaveau, Arthur; Lammertink, Rob G.H.; Bacchin, Patrice
    Clogging of channels by complex systems such as mixtures of colloidal and biological particles is commonly encountered in different applications. In this work, we analyze and compare the clogging mechanisms and dynamics by pure and mixture suspensions of polystyrene latex particles and Escherichia coli by coupling fluorescent microscopic observation and dynamic permeability measurements in microfluidic filters. Pure particles filtration leads to arches and deposit formation in the upstream side of the microfilter while pure bacteria form streamers in the downstream zone. When mixing particle and bacteria, an unexpected phenomenon occurs: the clogging dynamics is significantly delayed. This phenomenon is related...

  8. Why bumpy is better: The role of the dissipation distribution in slip flow over a bubble mattress

    Haase, A. Sander; Wood, Jeffery A.; Lammertink, Rob G.H.; Snoeijer, Jacco H.
    It has been observed that the amount of effective slip for transverse flow over a bubble mattress is maximum for bubbles that protrude somewhat in the channel flow. In this paper we provide an explanation for this characteristic feature by analyzing the spatial distribution of viscous dissipation for bubbles of varying protrusion angles. Bubbles protruding in the channel act as obstacles and reduce the effective channel height, thereby increasing the viscous dissipation in the bulk flow. At small scales, however, our numerical analysis reveals that increasing the bubble protrusion angle reduces the dissipation near the contact points of the no-slip...

  9. Can We Increase Psychological Well-Being? The Effects of Interventions on Psychological Well-Being: A Meta-Analysis of Randomized Controlled Trials

    Weiss, Laura A.; Westerhof, Gerben J.; Bohlmeijer, Ernst T.
    Background There is a rapidly growing interest in psychological well-being (PWB) as outcome of interventions. Ryff developed theory-based indicators of PWB that are consistent with a eudaimonic perspective of happiness. Numerous interventions have been developed with the aim to increase PWB. However, the effects on PWB measured as coherent outcome have not been examined across studies yet. This meta-analysis of randomized controlled trials of behavioral interventions aims to answer the question whether it is possible to enhance PWB. Methods A systematic literature search was performed in PsycINFO, Cochrane and Web of Science. To be included, studies had to be randomized controlled trials of...

  10. The use of a student group log to facilitate student and teacher learning

    Coenders, Fer
    In 21st century education students should have ample opportunities to collaborate on authentic problems. Many teachers however find it difficult to make the transfer from teacher to student-centered education. Giving students autonomy can be disquieting to teachers, as they fear to lose control of student learning. Teachers in a teacher development team developed context-based student learning material on the topic ‘salts’. Self-regulating student cooperative groups would work autonomously during a number of weeks using this material. To monitor the “what and how” of these groups, a student group log was developed. In this log all the work the group performed...

  11. Leve de aanbesteding

    Telgen, Jan
    De perikelen rond de Wmo stellen aanbestedingen in een kwaad daglicht. Ten onrechte. Slim opgezette aanbestedingen zijn juist een uitgelezen middel om maatschappelijke doelen te bereiken.

  12. Proportionaliteit verankerd in Aanbestedingswet

    Meijer, Rinke; Telgen, Jan

  13. IRSPP

    Telgen, Jan

  14. Innovaties om leveranciers scherp te houden

    Telgen, Jan

  15. Maatschappelijke ontwikkelingen en inkoop: kansen genoeg!

    Telgen, Jan

  16. Misverstanden over publieke inkoop op een rij

    Telgen, Jan

  17. (Cost)effectiveness of life review for Older Adults: Design of a randomized controlled trial

    Pot, Anne Margriet; Melenhorst, Anne-Sophie; Onrust, Simone; Bohlmeijer, Ernst T.
    Background Depression in older adults is a serious health problem with a poor prognosis. There is a need for indicated preventive psychological interventions for older adults, that show to be promising in preventing depressive disorders. Methods/design This manuscript describes the design of a study evaluating 'Looking for Meaning', a newly developed prevention course for older adults with depressive symptoms, based on life-review. Both clinical and economic effectiveness are evaluated in a pragmatic randomized controlled trial. The control condition of this 12-session preventive intervention is a 20-minute video movie. The primary outcome is symptoms of depression at post-treatment and follow-up (6 months after post-treatment)....

  18. Elan nodig bij aanbesteden

    Telgen, Jan; meent, Wim van de

  19. Aanbesteden: moet dat nou echt?

    Telgen, Jan

  20. Aanbesteden van wat?

    Telgen, Jan

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