Tesis para optar al grado de Magíster en Gestión y Dirección de Empresas / El objetivo de la presente tesis es proponer una estandarización del análisis de riesgo de sobre costo para los proyectos de la Vicepresidencia de Proyectos de BHP en Chile, a través del diseño de un bow tie tipo, que sirva como base de análisis permitiendo así optimizar el proceso actual. El bow tie es la actual herramienta de análisis y gestión de riesgos en BHP, donde se identifican causas e impactos asociados a un riesgo, lo que permite una correcta definición de controles preventivos y mitigadores. La realización de esta tesis se justifica por los desafíos que actualmente enfrenta la minería, la necesidad de contar con la capacidad productiva suficiente para cumplir con la demanda de cobre del mundo y un precio que obliga a ser eficientes con el uso de capital. Es aquí donde la predictibilidad de costos es uno de los desafíos en la industria de proyectos, por lo que la gestión de riesgos resulta una herramienta importante para enfrentar dichos desafíos. La metodología utilizada para el desarrollo de la presente tesis comprende un levantamiento de información a partir de los análisis de riesgo y lecciones aprendidas de tres proyectos ejecutados por BHP entre los años 2012 y 2017, sumado al análisis realizado por un panel de expertos que permite caracterizar el riesgo de sobrecosto, en específico, las potenciales causas que podrían generarlo y aquellos controles que permiten prevenir su ocurrencia y/o mitigar sus potenciales impactos. Como resultado se obtienen un bow tie estandarizado para el análisis del riesgo de sobre costo. El análisis realizado tiene como resultado catorce causas, doce controles preventivos y siete controles mitigadores, cada uno de ellos es descrito para la comprensión de los futuros usuarios. Los resultados de esta tesis permiten entregar una herramienta estandarizada que identifica tempranamente las principales causas y propone una batería de controles a ser aplicados en todos los proyectos de la Vicepresidencia. La implementación de esta herramienta no considera costos adicionales dentro del área y sus potenciales beneficios se consideran importantes. Se pone a disposición el resultado de esta tesis recomendando su uso como base para futuros análisis que permita tener una base de control estándar dentro de la compañía.

This thesis analyses issue of manufacture, typology and use of medieval arrowheads. In theoretical part describe historical evolution of bow and his archaeological discovery in Europe, especially from medieval times. After that is revealed historical evolution of arrowheads and describe their typology. In next chapters are mentioned ways of iron production, mainly in early medieval times and also describe technology of manufacture different types of arrowheads. There is a characterization of medieval arrow, his construction and characteristics. Continuously in this background research are revealing questions of penetration depend on the various types of arrowheads, which are testing on the most known types of armour like chainmail or breast plate. In experimental part of this paper are metallographicaly analyzing archaeological discoveries from the early and late medieval times. Conclusions about their manufacturing, treatment and possibilities of use are built on knowledge about arrowheads structures, hardness and shapes.

No description available.

The serious consequences of ship collisions necessitate the development of regulations and requirements for the subdivision and structural design of ships to reduce damage and environmental pollution, and improve safety. Differences in striking ship bow stiffness, draft, bow height and shape have an important influence on the allocation of absorbed energy between striking and struck ships. The energy absorbed by the striking ship may be significant. The assumption of a "rigid" striking bow may no longer hold good and typical simplifying assumptions may not be sufficient. The bow collision process is simulated by developing a striking ship bow model that uses Pedersen's super-element approach and the explicit non-linear FE code LS-DYNA. This model is applied to a series of collision scenarios. Results are compared with conventional FE model results, closed-form calculations, DAMAGE, DTU, ALPS/SCOL and SIMCOL. The results demonstrate that the universal assumption of a rigid striking ship bow is not valid. Bow deformation should be included in future versions of SIMCOL. A simplified bow model is proposed which approximates the results predicted by the three collision models, closed-form, conventional and intersection elements, to a reasonable degree of accuracy. This simplified bow model can be used in further calculations and damage predictions. A single stiffness can be defined for all striking ships in collision, irrespective of size. / Master of Science

This thesis shall identify the date origin of the composite bow within Mesopotamia and Elam. and both identify and quantify the design factors which lead to increased performance possible with composite construction. To accomplish this, the thesis begins by summarizing the problems and flaws that currently exist in the field of history as it applies specifically to archery and bow use. With problems identified, the thesis will then introduce the reader to the basics of bow mechanics, thereby laying the basis for physical testing. This in turn will empirically demonstrate flaws in the current iconographical method of bow identification. The thesis will then devise a new method for iconographic identification of composite construction that has greater proven accuracy, based upon proportional length, which will link extant artifacts with both physical test results and iconographic evidence. The reader shall then be led through a complete reevaluation of iconographical evidence for Mesopotamia and Elam starting at the beginning of the second millennium BCE and working backwards using this new method of iconographic evaluation to determine the point at which composite bow technology first appears in the ancient Near East. The thesis will finish with an overview of the above accomplishments and their potential impact on the study of ancient and military history. / Classics and World Languages / D. Litt. et Phil. (Classical Studies)

This research is an investigation of the Late Holocene technological transition from the spearthrower and dart to the bow and arrow in north central Texas. It is conducted through a theoretical approach that utilizes ethnographic research, experimental archaeology and the archaeological record to elucidate differences in the behaviors and hunting strategies of Late Archaic and Late Prehistoric groups. It first confirms that there was a transition. Second, a lithic analysis demonstrates that there are fundamental differences in the sizes of the stone dart and arrow points that relate to the propulsive requirements of the weapon systems. Third, it is shown these size differences constrain maintenance potentials and that indeed dart and arrow points exhibit stark differences in their life histories in spite of being employed for the same task. And finally, the faunal record suggests that this transition was associated with an increase in foraging efficiency.

Cette thèse présente une étude pour l'interprétation automatique d'images en milieu urbain. Nous proposons une application permettant de reconnaître différents monuments au sein d'images représentant des scènes complexes. La problématique principale est ici de différencier l'information locale extraite des points d'intérêt du bâtiment recherché parmi tous les points extraits de l'image. En effet, la particularité d'une image en milieu urbain vient de la nature publique de la scène. L'objet que l'on cherche à identifier est au milieu de divers autres objets pouvant interférer avec ce dernier. Nous présentons dans une première partie un état de l'art des méthodes de reconnaissance d’images en se concentrant sur l'utilisation de points d'intérêts locaux ainsi que des bases de données pouvant être employées lors des phases d'expérimentation. Nous retenons au final le modèle de sac de mots (BOW) appliqué aux descripteurs locaux SIFT (Scale-Invariant Feature Transform). Dans un second temps nous proposons une approche de classification des données locales faisant intervenir le modèle de machine à vecteurs de support (SVM). L'intérêt présenté dans cette approche proposée est le faible nombre de données requises lors de la phase d'entraînement des modèles. Différentes stratégies d'entraînement et de classification sont exposées ici. Une troisième partie suggère l'ajout d'une correction géométrique de la classification obtenue précédemment. Nous obtenons ainsi une classification non seulement de l'information locale mais aussi visuelle permettant ainsi une cohérence géométrique de la distribution des points d'intérêt. Enfin, un dernier chapitre présente les résultats expérimentaux obtenus, notamment sur des bâtiments de Paris et d'Oxford / This thesis presents a study for an automatic interpretation of urban images. We propose an application for the retrieval of different landmarks in images representing complex scenes. The main issue here is to differentiate the local information extracted from the key-points of the desired building from all the points extracted within the entire image. Indeed, an urban area image is specific by the public nature of the scene depicted. The object sought to be identified is fused within various other objects that can interfere. First of all, we present a state of the art about image recognition and retrieval methods focusing on local points of interest. Databases that can be used during the phases of experimentation are also exposed in a second chapter. We finally retain the Bag of Words modèle applied to local SIFT descriptors. In a second part, we propose a local data classification approach involving the Support Vector Machine model. The interest shown with this proposed approach is the low number of data required during the training phase of the models. Different training and classification strategies are also discussed. A third step suggests the addition of a geometric correction on the classification obtained previously. We thus obtain a classification not only for the local information but also for the visual information allowing thereby a geometric consistency of the points of interest. Finally, a last chapter presents the experimental results obtained, in particular involving images of buildings in Paris and Oxford

As the solar wind reaches Mercury it interacts with the planet’s magnetic field slowing down, forming a bow shock in front of the planet and diverting the flow around it. Along with the solar wind comes the interplanetary magnetic field, an extension of the sun’s magnetic field. The interaction between the bow shock and the interplanetary magnetic field impacts the behaviour of the plasma both up- and downstream of the bow shock. An important factor is the angle between the normal to the bow shock surface and the interplanetary magnetic field, θBN. The angle can be divided into two categories: quasi-parallel for when θBN < 45° and quasi-perpendicular for θBN > 45°. It is expected for a quasi-parallel configuration to have stronger fluctuations in both the solar wind upstream of the bow shock and in the magnetosheath downstream caused by reflected particles backstreaming into the solar wind. Quasi-perpendicular configurations are expected to have less fluctuations in both regions due to fewer solar wind particles being reflected back. In this thesis this connection is investigated at the bow shock at Mercury using magnetic field data from the MESSENGER mission. By looking at the data when the spacecraft travels through the thin bow shock the local θBN angle can be calculated. The fluctuation level is then calculated as the standard deviation of the magnetic field in a 30 second period upstream and downstream of the crossing. The results found are unexpected as the correlation between θBN and the fluctuation levels are weaker and more uniformly distributed than expected compared to similar studies conducted at Earth using the Cluster satellites. This is most likely due to the smaller spatial scale of the Hermean system: the structures perpendicular to the interplanetary magnetic field of upstream activity, such as SLAMS, cover a greater proportion of the bow shock than at Earth allowing them to extend over into neighbouring regions of different θBN values, giving a more uniform distribution of the fluctuation levels. / När solvinden når Merkurius växelverkar den med planetens magnetfält och solvinden saktas ned och avledes till att flöda kring planeten. Då solvinden decelereras formas en chock framför planeten, bogchocken. Tillsammans med solvinden kommer det interplanetära magnetfältet, som är en förlängning av solens magnetfält. Växelverkan mellan bogchocken och det interplanetära magnetfältet påverkar plasmat både upp- och nedströms från bogchocken. En viktigt faktor är vinkeln mellan normalen till bogchocken och det interplanetära magnetfältet, θBN . Bogchocken kan delas in i två kategorier: kvasi-parallell då θBN < 45° och kvasi-vinkelrät då θBN > 45°. Vid kvasi-parallella förhållanden förväntas starkare fluktuationer i magnetfältet både uppströms i solvinden och nedströms i magnetskiktet, orsakat av reflekterade partiklar som färdas in i den inkommande solvinden. Kvasi-vinkelräta förhållanden förväntas ha mindre fluktuationer då färre partiklar reflekteras. I den här uppsatsen undersöks kopplingen vid Merkurius bogchock med data från rymdsonden MESSENGER. Genom att använda data då rymdsonden färdas igenom den tunna bogchocken kan det lokala värdet på θBN uträknas. Fluktuationsnivåerna räknas ut som standardavvikelsen av magnetfältet under en 30 sekundersperiod uppströms och nedströms från korsningen. Resultaten är ej som förväntade då kopplingen mellan θBN och fluktuationsnivån är mycket svagare och jämnt fördelade än förväntat, baserat på resultat från jorden från Cluster-satelliterna. Den mest troliga förklaringen är att Merkurius och dess bogchock är mindre än jordens: de strukturerna som är vinkelräta till det interplanetära magnetfältet hos uppströmsfenomen, t.ex SLAMS, täcker då en större proportion av bogchocken än vid jorden vilket tillåter dem att sträcka sig in i närliggande regioner med annorlunda θBN värden, vilket ger en mer jämn utbredning av fluktuationsnivåerna.

Since Venus is an unmagnetized planet, it doesn’t interact with the solar wind in the same way as planets with an intrinsic magnetic field do. Due to its conductive ionosphere, however, it still possesses an induced magnetosphere. Venus’s magnetosphere contains different boundaries, identified by changes in the plasma or magnetic field characteristics. The boundaries we studied in this project are the bow shock and the Ion Composition Boundary (ICB). Previous studies identified the boundaries’ locations and compared them with plasma measurements outside of the magnetosphere, finding how the boundaries react to varying solar wind upstream conditions. What has been more rarely done, instead, is to find the analytical dependency of the bow shock and ICB on the upstream conditions. This was the purpose of this project. Developing this comprehensive analytical model allows us to determine the location of the boundaries, once the upstream conditions are defined. We used a database of boundary crossings and upstream conditions measurements deriving from the Venus EXpress (VEX). The procedure we followed was first to divide the boundaries crossings into bins, analyzing one upstream condition at a time. Then, we fitted the crossings using analytical equations depending on geometrical parameters. For the bow shock we used a conic section with semi-latus rectum L and eccentricity ε as geometrical parameters, for the dayside ICB we used a circumference with the radius R as geometrical parameter. We fitted these geometrical parameters with the upstream conditions in each bin and found the final model. The final equation for the bow shock depends on the Interplanetary Magnetic Field (IMF) magnitude, the solar wind mass flux, and the angle between the IMF direction and the local shock normal. For the ICB the final equation depends on the solar wind energy flux and the solar Extreme UltraViolet (EUV) flux. Given these solar wind and IMF properties, the geometrical parameters of the boundaries are uniquely identified. Then, we were able to determine the boundaries’ locations and shapes with higher accuracy than the general fitting models that don’t consider upstream conditions. For the bow shock we improved the accuracy by 17%, for the ICB by 8%. / Eftersom Venus är en omagnetisk planet växelverkar den inte med solvinden på samma sätt som planeter med ett inneboende magnetfält. På grund av sin ledande jonosfär har den dock fortfarande en inducerad magnetosfär. Venus magnetosfär innehåller olika gränser, identifierade av förändringar i plasma- eller magnetfältets egenskaper. Gränserna vi studerade i det här projektet är bogshocken och Ion Composition Boundary (ICB). Tidigare studier identifierade gränsernas lägen och jämförde dem med plasmamätningar utanför magnetosfären, och hittade hur gränserna ändras med varierande solvind uppströms. Vad som har gjorts mer sällan är att hitta det analytiska beroendet av bogchocken och ICB på uppströmsförhållandena. Det var syftet med det här projektet. Genom att utveckla de här analytiska modellerna kan vi bestämma placering för gränserna när uppströmsförhållandena har definierats. Vi använde en databas med gränsövergångar och mätningar av uppströmsförhållanden härrörande från Venus EXpress (VEX). Proceduren vi följde var först att dela upp gränsövergångarna i dataintervall och analysera ett uppströmsläge i taget. Sedan anpassade korsningarna med hjälp av analytiska ekvationer beroende på geometriska parametrar. För bogshocken använde vi en konisk sektion med semi-latus rektum L och excentricitet ε som geometriska parametrar, för dagsida ICB använde vi en omkrets med radien R som geometrisk parameter. Vi anpassade de här geometriska parametrarna för olika uppströmsförhållanden och tog fram en modell. Den slutliga ekvationen för bogshocken beror på det interplanetära magnetfältets (IMF) magnitud, solvindens rörelsemängd och vinkeln mellan IMF och den lokala shocknormalen. För ICB beror den slutliga ekvationen på solvindenergiflödet och extrem ultraviolett (EUV) flöde. Med avseende på de här solvinds- och IMF-egenskaperna är de geometriska parametrarna för gränserna identifierade. Sedan kunde vi bestämma gränsernas placeringar och former med högre noggrannhet än de allmänna modellerna som inte tar hänsyn till uppströmsförhållanden. För bogchocken förbättrade vi noggrannheten med 17% och för ICB med 8%.

The Vendel period, Early Medieval or Merovingian period as it’s called in the rest of Europe, is a time full of wonderful artefacts. Many are those that have heard of the fantastic boat-graves in Vendel and Valsgärde in Sweden and the very similar Sutton Hoo in Great Britain, but what about Gotland? Most of the papers discussing this period focus only on the area around lake Mälaren but I want to contribute by placing Gotland and its artefacts in the center. This paper will focus on disc-on-bow brooches, the special kind of gilded buckles, inlaid with garnets or niello, that are found mostly in women graves from the Vendel period on Gotland and how they can be dated from the differences in shape and the ornamentation. The aim of this text is to by analysing the grave finds in several women graves on Gotland get an idea about the woman who wore the brooch and her social status. The discussion has a gender theme and will discuss the sometimes flawed theory that graves that contain jewellery always belongs to women and graves with weapons always belongs to men. This study shows that the button-on-bow brooches does not indicate any clear differences between women with brooches and those who does not have them, but other artefacts in the graves might.