2,946 research outputs found
Bas-Relief Modeling from Normal Layers
No full textBas-relief is characterized by its unique presentation of intrinsic shape properties and/or detailed appearance using materials raised up in different degrees above a background. However, many bas-relief modeling methods could not manipulate scene details well. We propose a simple and effective solution for two kinds of bas-relief modeling (i.e., structure-preserving and detail-preserving), which is different from the prior tone mapping alike methods. Our idea originates from an observation on typical 3D models which are decomposed into a piecewise smooth base layer and a detail layer in normal field. Proper manipulation of the two layers contributes to both structure-preserving and detail-preserving bas-relief modeling. We solve the modeling problem in a discrete geometry processing setup that uses normal-based mesh processing as a theoretical foundation. Specifically, using the two-step mesh smoothing mechanism as a bridge, we transfer the bas-relief modeling problem into a discrete space, and solve it in a least-squares manner. Experiments and comparisons to other methods show that (i) geometry details are better preserved in the scenario with high compression ratios, and (ii) structures are clearly preserved without shape distortion and interference from details.Accepted author manuscriptMaterials and Manufacturin
FM Transceiver for Wireless Communication: Audio and Intermediate Frequency Amplifiers
No full textIn this bachelor thesis the design process of the audio and intermediate frequency amplifiers for a wireless FM tranceiver is documented and explained. The project was done using only descrete components for educational purposes.2019 Ivor Bas, Victor hoedemakerElectrical Engineerin
Inventory for a Reverse Journey. Photographic Image and Found Object - An investigation of travel and material transformation as a paradigm of artist's practice: Ed Ruscha, Douglas Huebler, Bas jan Ader, Jimmie Durham, Gustav Metzger, Kurt Schwitters & Cian Quayle.
No full textInventory for Reverse Journey is the title of a collection of photographic artefacts and found objects, which I have collected over the last twenty years. The title refers to one specific type of artist's journey, which is applicable to the `chronotope' of my archive, as a `metaphorical journey in space and time' (Bakhtin 1981, p. 81). The `city',`provincial town', `road', `threshold' and `interior' are recurrent motifs, which Bakhtin fused together to describe the historical evolution of the novel in relation to its different genres. Bakhtin's motifs are expanded as the basis of an evolutionary nomenclature of the artist's-journey, as a form of spatial mapping and identity formation. Alongside other sources from literature (Alain Robbe-Grillet), cinema (Michelangelo Antonioni), psychoanalysis (Kierkegaard) and critical theory (Walter Benjamin) I have developed a theoretical framework, which initially originated in an empirical process, that is reflected in the antecedents of this project. The research process, as a journey itself, has concretised this approach within a systems-based practice. This is mirrored in the work of the artists under investigation, as their differences and similarities are highlighted within a broad contextual analysis. Accordingly the tone of the writing shifts its register at different points in the thesis.
My journey is just one example of several paradigmatic formations of `travel' as a strategy, which investigates the work of six different artists, as a voluntary or involuntary form of exile. A deskilled use of the photographic image is examined in the work of Ed Ruscha, Douglas Huebler and Bas jan Ader in the spatial mapping of their chosen locations. The work of these artists manifests travel, as a strategy, in a benign form of regional and expatriate exile. The investigation shifts its focus from the New World to Europe, where the work of Jimmie Durham, Gustav Metzger and Kurt Schwitters is analysed in relation to their transformation of found objects and materials, and their relationship with a former 'home'. Their position registers different degrees of the `impossibility of return' to a point of origin, which exists in the mind rather than as a physical location. The transience of their work, and use of disparate materials, is counterbalanced by their physical presence in the work. Conversely Ader, Huebler and Ruscha are linked by a scale of decreasing visibility, as they are sublimated within their work in the formation of, what is now construed as, a unique photographic presence. The starting point for which is a return to the formative years of conceptualism in the 1960's, which set the scene for Durham and Metzger from the 1970's onwards. The spectre of Schwitters practice of forming (Formung) and unforming (Entformung) is significant for my analysis of the dematerialisation of the art-work and artist, by processes of series and repetition, distance and proximity, movement and stasis. Although `travel' is a ubiquitous term, I continue to use it as a portmanteau, which carries with it the themes and `salient' features of a typology of artist's journeys. In a moment of perceived obsolescence as digital information systems engender a culture of `selective-amnesia', these thoughts have informed my work, which runs parallel to the artist case-studies, and the material transformation of the photographic image and found object
Retour d\u92expériences après la tempête Xynthia en France, leçons pour les Pays Bas; les dégâts suite à l\u92inondation
No full textLe 28 février 2010, vers 2 heures du matin, la tempête Xynthia atteint la côte occidentale de la France. A plusieurs endroits, les digues, dunes et d\u92autres ouvrages cédèrent, donnant lieu à des inondations du littoral. Plus de 50.000 hectares de terres furent inondées. Au total, la France compta 47 morts suite à la tempête, la plupart d\u92entre eux suite à la crue. Essentiellement les régions de la Vendée et de la Charente-Maritime endurèrent de terribles privations. Les dégâts et les victimes ne sont pas uniquement la conséquence du phénomène naturel, mais également des interventions de l\u92homme ou le manque de celles-ci. Les Pays-Bas pourraient tirer des leçons de ces inondations côtières françaises. Les circonstances aux Pays-Bas et en France sont, dans une grande mesure, comparables. La France, elle aussi, connaît des zones côtières à basse altitude sensibles aux inondations. Certes, le niveau de protection aux Pays-Bas est plus élevé, mais une inondation aux Pays-Bas est aussi bien concevable. Tout comme en France, une inondation du littoral néerlandais est causée par une combinaison de la marée, d\u92une tempête et d\u92une surcote. Les législations et les réglementations présentent des concordances ; leurs bases datent de l\u92époque de Napoléon. Ce livre décrit l\u92inondation par la tempête Xynthia et ses conséquences. Nous en tirons des leçons et nous formulons des avis pour les Pays-Bas. Nous cherchons à nous associer à une protection contre l\u92inondation à trois volets: la prévention, l\u92aménagement du territoire et la maîtrise des catastrophes
Understanding the influence of beach morphology on the alongshore variance in wave run-up on an intermediate reflective beach, considering bars and cusps
No full textThe topic which is considered in this thesis is: understanding the influence of beach morphology on the alongshore variance in wave run-up on an intermediate reflective beach, considering bars and cusps. The focus of this thesis is laid inside the swash zone, in which the water motion is present of waves that run up and run down on a beach. Energy from wave run-up could deliver erosion to the beach. It is relevant to know what the magnitude is of run-up during extreme events, in order to protect the beach. Several studies are done to wave run-up. There are relations which specify run-up, however, the alongshore variability is not studied in detail and less knowledge is available about this topic. At Anmok beach in South-Korea an intermediate reflective beach is present containing beach cusps and crescentic sandbars. A rhythmic bar and beach state contains the most complex morphology, furthermore the morphology changes a lot within intermediate beaches (Wright and Short [1]). The characteristics of this beach are used to perform an analysis to the influence of cusp and bar morphology on alongshore variation in wave run-up. Run-up is composed of setup and swash. Setup is the super elevation of the mean water level, swash is ‘’a time-varying location of the intersection between the ocean and the beach’’ according to Stockdon, Holman [2]. Swash can be decomposed into two parts, incident band swash and infragravity band swash. Swash and setup depend on beach slope, deep-water wave height and the deep water period[2]. To analyse the alongshore variability multiple bathymetries have been generated on which 500 waves are modelled for 60 different wave condition. First of all a reference case is modelled with a uniform bathymetry. Secondly beach cusps are used as input with different length scales and at last a beach cusp with crescentic sandbar is used. The length scales of the cusps are 452, 300 and 100 metres. The bathymetries are idealized bathymetries with the characteristics of Anmok beach. The run-up and components are calculated and an analysis is done to the magnitude of run-up and the standard deviation along the beach. The magnitude of run-up is lower for a cusp system compared with the reference situation and even lower for the cusp bar system. Furthermore there are no large differences in magnitude of run-up between different cusp lengths. A larger alongshore variance is observed when a cusp (bar) system is present. A cusp system of 452 metres contains larger run-up at the horn compared with the embayment, this holds for large and small wave heights. The difference is 18% and 8.4% respectively. However, when a cusp bar system is present less alongshore variability is visible and an opposite behaviour is visible for small wave heights. In this case the same pattern can be seen for large wave heights. A difference of 3.68% is seen when the horn is compared with the embayment. However, for small wave heights the run-up is 10.5% smaller at a horn compared with an embayment. A cusp length of 100 metres shows different behaviour compared with a cusp length of 452 metres. Run-up is larger at an embayment compared to the horn. This holds for large wave heights. The alongshore variance is in this case larger compared to larger cusp lengths. A cusp of 452 metres and 300 metres leads to similar results, whereas a 100 metres cusp shows deviations. It could be edge waves which could have an influence on a cusp with a length of 100 metres.<br/
Intra-operative bacterial contamination : control and consequences
No full textEen combinatie van gedragsmaatregelen en een beter luchtinblaassysteem in de operatiekamer leidt tot een afname van het aantal bacteriën bij plaatsing van een knie- of heupprothese. Hierdoor neemt de kans af op infectie van de prothese en op problemen met wondgenezing na de operatie. Dit blijkt uit onderzoek van Bas Knobben, uitgevoerd bij de afdeling Orthopedie en de vakgroep Biomedical Engineering van het Universitair Medisch Centrum Groningen. Deze bevindingen kunnen ertoe bijdragen dat gewrichtsprothesen minder vaak infecteren en vervangen moeten worden. Hij promoveert op 26 april 2006 op zijn onderzoek aan de Rijksuniversiteit Groningen.
In elke operatiekamer kunnen ondanks strenge hygiënische maatregelen bacteriën voorkomen die een mogelijk risico vormen voor infectie van prothesen en problemen met wondgenezing na de operatie. Tot nu toe was de omvang hiervan onduidelijk. Uit het onderzoek van Knobben blijkt dat bij 36 procent van de plaatsingen van heupprothesen bacteriën aanwezig waren op het instrumentarium en op verwijderde botsnippers bij het inbrengen van de prothesen. Ook bleek er een verband te zijn tussen het vóórkomen van deze bacteriën en het optreden van verstoorde wondgenezing en infectie van de prothesen.
Gedragsmaatregelen
Knobben onderzocht of gedrags- en technische maatregelen, aanvullend op de gebruikelijke hygiënerichtlijnen, de kans op bacteriële besmetting tijdens de operatie verkleinen. Uit zijn onderzoek blijkt dat de combinatie van deze maatregelen in een operatiekamer de kans op aanwezigheid van bacteriën deed afnemen van 34 procent naar 8 procent. Tegelijk nam de kans op infectie van prothesen, verstoorde wondgenezing en wondinfectie beduidend af.
De gedragsmaatregelen die onder andere werden genomen, zijn het beperken van het spreken en het in- en uitlopen van de operatiekamer door het operatiekamerpersoneel, het gecontroleerd bewegen, het juiste gebruik van het neus-/mondkapje en een beter gebruik van het gebied onder de luchtstroom. Een van de technische maatregelen betrof het gebruik van een beter luchtinblaassysteem (laminaire airflow). Hierbij vindt een constante aanvoer van schone lucht plaats boven het operatiegebied en worden bacteriën via verticale luchtstromen afgevoerd.
Kosteneffectief
Met dit onderzoek toont Knobben aan dat gedragsmaatregelen en een beter luchtinblaassysteem in de operatiekamer infecties van prothesen en problemen met wondgenezing kunnen voorkomen. De maatregelen zijn bovendien kosteneffectief: de gemiddelde totale kosten per patiënt met een eerste (primaire) prothese zonder infectie zijn ongeveer € 15.000, zo’n 3,5 keer lager dan die van een patiënt met een geïnfecteerde prothese (ongeveer € 52.000). De resultaten van dit proefschrift hebben ertoe geleid dat het Universitair Medisch Centrum Groningen de aanvullende gedrags- en technische maatregelen toepast bij het plaatsen van prothesen.
Verdubbeling
In Nederland zijn in 2004 ongeveer 25.000 heup- en 20.000 knieprothesen geplaatst. De belangrijkste indicatie voor het plaatsen hiervan is gewrichtsslijtage. De verwachting is dat door vergrijzing het aantal mensen dat in aanmerking komt voor deze operaties de komende twintig jaar zal verdubbelen. Bij ongeveer één tot vier procent van de patiënten treedt na plaatsing een bacteriële infectie op.
"Causes, Consequences and Dynamics of 'Complex' Distributions of Technological Activities: The Case of Prolific Inventors"
No full textWe provide a framework for understanding the causes and consequences of the observed shapes of the distributions of individual inventors' productivities. We review a literature that begins with Lotka's (1926) "law" regarding the persistence of variability in scientific productivity at any point in time and also over time. We discuss use of the "power law" and the Pareto distribution to describe and explain the empirical distributions. We focus on the upper parts of the frequency distributions for inventors exploring the processes underlying knowledge accumulation at the individual level, including its features, characteristics, and structural trends. Finally we explore the specific processes by which these individuals create, maintain, and increase knowledge accumulation as their careers evolve.patents, inventors, prolific, lotka
Preliminary note on the red shrimp Aristeus Antennatus
No full textOn ne dispose que de peu de données sur la biologie de A. antennatus qui a une grande importance commerciale en Méditerranée occidentale. Différentes mesures ont été effectuées et étudiées sur 1 369 individus. La distribution de la longueur totale des individus pendant les différents mois montre I'existence de deux groupes de taille différente dont l'importance varie au cours de l'année. L'auteur a aussi étudié la relation entre ie poids et ia taille des individus examinés ainsi que leur sexualite.A. antennatus has great commercial importance in the western Mediterranean and few biological data on this species are available. Different measurements have been made and studied on 1,369 samples. The distribution of total length of each sample demonstrates the existence of two groups of different size, the importance of which varies in the course of the year. The author has also studied the relation of weight
to size of the samples as well as their sexuality.28528
ASO Author Reflections: Vascular Resection in Perihilar Cholangiocarcinoma Surgery
No full textvascular resection in hilar cholangiocarcinom
Stability of rock on mild slopes
No full textUntil now, an extensive design method for mild slopes has not been available. The aim of this thesis is to understand the stability of rock on mild slopes under wave attack for impermeable cores in order to optimize designs. Physical model tests have been executed to study this stability for a 1:8 slope. Mossinkoff (2019) executed physical model tests for a 1:10 slope and a re-analysis of these tests is included in this thesis as well. Damage caused by entrained rocks is quantified by damage parameters using stereophotogrammetry and coloured rocks in strips. In this study, the influence of several hydraulic and structural parameters on damage parameters has been investigated for mild slopes. A positive correlation has been found between the significant wave height and the damage parameters. Besides this, based on the analysis it can be concluded that the wave steepness and damage parameters are negatively correlated. An increase in layer thickness of the rocks does not seem to increase the stability of rock on mild slopes. However, the slope angle does have an effect on the stability as a milder slope is associated with less damage. Another conclusion is that more damage continues to be observed even after 15 000 waves. Based on the results of the physical model tests, a design formula is developed for mild slopes to be able to increase efficiency in designs of coastal structures for these mild slopes. This study also provides evidence that rocks on mild slopes have different characteristics of damage and damage development compared to steep slopes. The largest share of entrained rocks transport in upward direction and rocks on mild slopes seem to be more mobile compared to steep slopes. This suggested that it might be more efficient to study the moment when the filter layer or the core becomes visible instead of the static stability of rock within the armour layer itself.Civil Engineering | Hydraulic Engineerin
- …
