113 research outputs found
SHELL PERSONAL ORNAMENTS CRAFT AT THE SITE OF THA KAE, LOPBURI PROVINCE, CENTRAL THAILAND. TRACING THE SOUTHWARD DISPERSAL OF THE DRILLING TECHNIQUE
The collection of mollusk remains excavated at Tha Kae has been recently re-analyzed and identified as to genera or family level. Out of 5 main fresh/salt-water mollusk families, only Conus and Tridacna were used to make personal ornaments and, for Tridacna, small adzes, during the local Bronze Age (BA) (c. 1100-500 BCE).The study of 100 kg of production debris and of whole/fragmentary ornaments demonstrated the manufacturing cycle consisted of two main steps: 1) Procurement of the raw material; 2) Transformation in a sequence of six stages of the raw material into the base material for luxuries that arguably entered inter-regional exchange circuits. The manufacturing cycle, possibly part of a system organized at the community level, implied procurement expeditions and skilled craftspeople able to organize and use the relevant tool kit, whose origin can be traced back to the lower Yangtze valley (late fourth millennium BC). The shell-craft cycle also sheds light on the cognitive processes of the craftsmen, who had to make a choice in order to maximize the output of their work.The study provides newly organized data of direct archaeological interest to the field of Southeast Asian pre-protohistory, as well as to those of social and cultural anthropology, cognitive science, marine palaeobiology and to palaeogeography
Informationsgehalt von SLB-Emissionen : wie reagiert der Aktienmarkt auf die Ausgabe von Sustainability-Linked-Bonds?
Die relative Neuheit und die zunehmende Relevanz von Sustainability-Linked-Bonds (SLBs) sowie deren klare Abgrenzung zu anderen nachhaltigen Anleihensinstrumenten konstituierten die Motivation und den Bedarf dieses Instrument zu analysieren. WĂ€hrend sich bisherige Studien mehrheitlich auf die Preisaspekte und die damit verbundenen, potentiell attraktiven, Kapitalkosten fokussieren, wurde in dieser Arbeit die Signalwirkung von SLBs analysiert.
Unter der PrĂ€misse der semi-strengen Informationseffizienz und unter BerĂŒcksichtigung der Signaltheorie wurde in der vorliegenden Arbeit untersucht, wie der Aktienmarkt auf die Ausgabe von SLBs reagiert, ob die Reaktion von bestimmten SLB- oder Firmencharakteristika abhĂ€ngt, und ob sich SLBs als Instrument zur Signalisierung der Nachhaltigkeitsabsicht eignen. Die Verwendung einer möglichst grossen und damit reprĂ€sentativen Stichprobe war ein Ziel der Arbeit. GemĂ€ss Bloomberg wurden zwischen 2018 und 2022 weltweit 430 SLBs ausgegeben. Aufgrund der VerfĂŒgbarkeit von Renditedaten konnten insgesamt 275 SLBs von 198 unterschiedlichen Emittenten in der Stichprobe berĂŒcksichtigt werden.
Die Ergebnisse der Ereignisstudie haben gezeigt, dass weder die AnkĂŒndigung noch die eigentliche Emission der untersuchten SLBs zu einer signifikanten Aktienpreisreaktion gefĂŒhrt haben: Die fĂŒr die Stichprobe aggregierte abnormale Rendite ist am Ereignistag (AAR) und im Ereigniszeitfenster (CAAR) nicht signifikant unterschiedlich von Null. Da nur wenige Ereignisse (AnkĂŒndigung von SLB-Emissionen) einzeln signifikant sind, konnte zudem kein signifikanter ErklĂ€rungszusammenhang zwischen den abnormalen Renditen (AR und CAR) und den untersuchten Bond- und Unternehmenscharakteristika festgestellt werden (ErklĂ€rung von Insignifikanz): Der Science-Based-Target-Score als Proxy fĂŒr die Zielambition, das Vorhandensein einer Call-Option als Proxy fĂŒr die Penaltyhöhe, das relative Emissionsvolumen, die Neuartigkeit der SLB-Emission fĂŒr die Emittenten und das Nachhaltigkeitsprofil (ESG-Rating) der Emittenten sind als erklĂ€rende Variablen der abnormalen Rendite (Querschnittsregression) nicht signifikant unterschiedlich von Null. Die zusĂ€tzliche Analyse entsprechender Substichproben bestĂ€tigte diese Resultate.
Aus diesen Ergebnissen wurde gefolgert, dass bisherige SLB-Emissionen, unabhĂ€ngig von den geprĂŒften Unternehmens- und Bondcharakteristika, die Zukunftserwartung der AktionĂ€re nicht beeinflusst haben; Die SLBs haben keine neue Information fĂŒr die AktionĂ€re generiert. Emittenten haben durch die Ausgabe der SLBs keine Aktienpreissteigerung verzeichnen können. SLBs scheinen sich daher nicht primĂ€r als Instrument zur Signalisierung von Nachhaltigkeitsbestrebungen zu eigenen: Der Aktienmarkt reagierte, wie bei klassischen Anleihen d.h. trotz des Nachhaltigkeitsaspekts, indifferent auf die Aus-gabe der SLBs. Diese Ergebnisse sprechen, ĂŒbereinstimmend mit dem aktuellen SLB-Forschungsstand, gegen das Signalargument als Treiber von SLB-Emissionen
El método de anålisis de inteligencia en el Modelo de Planeamiento Militar para la Defensa argentino
En el año 2009, el Poder Ejecutivo Nacional, a instancias del Ministerio de Defensa, dicta el Decreto 1714/09. La norma origina la variaciĂłn del paradigma de planeamiento para la Defensa, desplazando aquella basada en hipĂłtesis de conflicto, para dar paso al mĂ©todo de Planeamiento en Base a Capacidades (PBC). Este proceso, requiere de la asistencia del producto resultante de la labor de anĂĄlisis de inteligencia estratĂ©gico, que en su concepciĂłn difiere de aquĂ©l que resume la bĂșsqueda de datos e informaciones, para dar paso a la intervenciĂłn de profesionales interdisciplinarios, que ofrezcan al decisor el conocimiento del contexto que impone la dinĂĄmica de interrelaciones estatales a nivel estratĂ©gico. El âciclo de producciĂłn de inteligenciaâ brindado en los años 50, por Sherman Kent y Washington Platt, ante el PBC, da lugar a mĂ©todos innovativos prospectivos, que esta investigaciĂłn intenta develar.Facultad de Ciencias JurĂdicas y Sociale
Defects Vibrations Engineering for Enhancing Interfacial Thermal Transport
To push upper boundaries of effective thermal conductivity in polymer
composites, a fundamental understanding of thermal transport mechanisms is
crucial. Although there is intensive simulation research, systematic
experimental investigation on thermal transport in polymer composites is
limited. To better understand thermal transport processes, we design polymer
composites with perfect fillers (graphite) and defective fillers (graphite
oxide); we choose polar polyvinyl alcohol (PVA) as a matrix model; and we
identify how thermal transport occurs across heterogeneous interfaces. Measured
thermal conductivities of in PVA/defective filler composites is higher than
those of PVA/perfect filler composites, while measured thermal conductivities
in defective fillers are lower than those of perfect fillers. An effective
quantum mechanical model is developed, showing that the vibrational state of
the defective level plays a critical role in enhancing the thermal conductivity
with increased defect concentration. Our experimental and model results have
suggested that defects in polymer composites may enhance thermal transport in
polymer composites by promoting vibrational resonant couplings.Comment: Enclosed: (i) Main Manuscript, including 5 main figures. (ii)
Supplementary Information, including 16 Supplementary Figures and one
self-contained theoretical sectio
Intensive archaeological survey in southeast Asia: methodological and metallurgical insights from Khao Sai On, central Thailand
Intensive surface surveys are a well-established method in the landscape archaeology of many parts of the world, but have remained relatively rare in Southeast Asian research up to present. This paper summarises the contribution of existing surveys in the latter region and offers results from a short but informative survey of a metal-producing landscape in central Thailand. We argue that there is much to be gained from a fuller integration of systematic landscape reconnaissance into wider Southeast Asian research agendas and consider some of the strengths and weaknesses of such an approach in this cultural and physical environment
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Maurice Ravel's "Tzigane": A link between theclassical and the Hungarian-Gypsy traditions
In writing Tzigane, Maurice Ravel went beyond the mere imitation of an exotic style composing a piece that closely resembles in form, technique, and even timbre the gypsy works with which he was familiar. In addition to drawing on the Hungarian-Gypsy tradition, Ravel brought his own mastery into that world. These insights suggest to me that knowledge of the Hungarian-Gypsy violin tradition can lead to a more informed and expressive performance of Tzigane
Control Design of an Electrical Power System (EPS) for people with reduced mobility
Ce travail de thĂšse a Ă©tĂ© effectuĂ© au sein du Laboratoire GIPSA-Lab de Grenoble, sous la direction de Carlos Canudas de Wit et co-encadrĂ© par Franck Quaine et Violaine CahouĂ«t.Ce travail a Ă©tĂ© rĂ©alisĂ© dans le cadre du projet ANR-09-VTT-14-01/06 « VOLHAND ». Il sâinscrit dans le contexte gĂ©nĂ©ral des nouvelles gĂ©nĂ©rations de Direction AssistĂ©e Electrique (DAE, ou EPAS en anglais pour Electronic Power Assistance Steering) avec pour objectif spĂ©cifique de tenir compte des caractĂ©ristiques des conducteurs Ă mobilitĂ© rĂ©duite. En effet, Ă ce jour, il nâexiste pas de systĂšme de direction assistĂ©e adaptĂ© aux capacitĂ©s articulaires (rhumatismes divers), musculaires (diminution de force, sĂ©nescence), ou encore aux douleurs ressenties par le conducteur. Le principal objectif de cette thĂšse est donc de proposer une mĂ©thodologie gĂ©nĂ©rale permettant d'adapter une DAE standard aux conducteurs Ă mobilitĂ© rĂ©duite. Le mĂ©moire est organisĂ© en cinq chapitres.Chapitre 1, intitulĂ© Context and objectives of the study presente lâimpact Ă©conomique et sociĂ©tal, la problĂ©matique et lâobjectif. Ensuite, la stratĂ©gie permettant dâatteindre lâobjectif ainsi spĂ©cifiĂ© est prĂ©cisĂ©e.Chapitre 2, intitulĂ© Models for simulation, est dĂ©diĂ© Ă lâĂ©tablissement dâun modĂšle mathĂ©matique du systĂšme de DAEs prenant bien en compte lâĂ©lasticitĂ© en torsion de la colonne de direction due Ă la prĂ©sence dâun capteur de couple. Parmi les entrĂ©es de ce modĂšle Ă deux degrĂ©s de libertĂ©, une attention est faite en ce qui concerne la description du couple de frottement du contact pneumatique-route. Un modĂšle de frottement dynamique, basĂ© sur le modĂšle de LuGre, est dĂ©veloppĂ© pour dĂ©crire ces phĂ©nomĂšnes. Une amĂ©lioration du modĂšle est ainsi proposĂ©e.Chapitre 3, intitulĂ© Oscillation annealing and torque observer design, commence par mettre en Ă©vidence les consĂ©quences de la prĂ©sence du mode souple associĂ© Ă lâĂ©lasticitĂ© en torsion du capteur de couple sur le ressenti au niveau du volant. Une commande LQ est proposĂ©e pour limiter les oscillations dues Ă ce mode souple. Enfin, un observateur pour estimer le couple conducteur et le couple rĂ©sultant du frottement pneumatique route est dĂ©veloppĂ©.Chapitre 4, intitulĂ© Power steering booster stage, se focalise dans un premier temps sur la nature des courbes dâassistance utilisĂ©es dans le cadre des DAE. En effet, lâĂ©tat de lâart sur le sujet met en Ă©vidence lâabsence de justification de la forme de ces courbes gĂ©nĂ©ralement fonction de la vitesse du vĂ©hicule et du couple appliquĂ© par le conducteur. Dans ce chapitre on propose de calculer de nouvelles lois en se fondant sur lâapproche par optimisation (minimisation du jerk couplĂ© avec la loi de puissance de Steven). Les rĂ©sultats obtenus montrent que la minimisation du critĂšre fondĂ© sur le jerk du volant et la loi de puissance de Steven peut permettre de reproduire les lois existantes dâassistance et leur apportent une justification. Ils confirment Ă©galement la forte influence du frottement (couple) au niveau du contact roue-sol. La seconde partie de ce chapitre est consacrĂ©e au dĂ©veloppement dâune mĂ©thodologie gĂ©nĂ©rale dâadaptation des lois dâassistance (cartographie standard initiale) aux exigences du conducteur Ă mobilitĂ© rĂ©duite (typiquement ici une personne prĂ©sentant une asymĂ©trie.Chapitre 5, intitulĂ© Experimental validation NeCS-Car benchmark, commence par dĂ©tailler la plateforme expĂ©rimentale prĂ©sente au laboratoire GIPSA-LAB et utilisĂ©e pour Ă©valuer et valider les nouvelles lois dâassistance adaptĂ©es au conducteur Ă mobilitĂ© rĂ©duite. La stratĂ©gie globale dâassistance de couple au volant pour un conducteur prĂ©sentant une asymĂ©trie, est testĂ©e sur le banc avec la NeCS-Car. Les rĂ©sultats issus du protocole montrent la validitĂ© de la stratĂ©gie proposĂ©e.Ce mĂ©moire se termine avec une partie General conclusions and perspectives oĂč les principales contributions sont dâabord rappelĂ©es, puis oĂč des perspectives pour complĂ©ter et prolonger ce travail sont proposĂ©es.Nowadays, vehicles have been widely equipped with power assistance steering systems and the way of providing assist torque is various. Electronic Power Assistance Steering (EPAS) systems have the tendency to replace the Hydraulic Power Assistance Steering (HPAS) systems, due to better fuel consumption, better road feel feedback to the driver and better return-to-center performance of the steering system. Actual EPAS systems are designed basing on a general driverâs profile and they try to mimic the behavior of the HPAS system. Main goal of this thesis is to propose a general methodology to adapt standard EPAS for drivers with reduced mobility. Toward this general goal, following contributions are integrant part of this thesis.First, a mathematical model of the steering system that keeps into account the torsion of the steering column is introduced. This model is influenced by two exogenous inputs: the tire-road friction torque and the driver's torque. Mathematical models for these inputs are also proposed. Due its importance on the steering system, great attention is dedicated to the description of the tire-road friction torque. This torque includes the contribution of two main phenomena: the self-alignment and the sticking friction torques. They appear, respectively, at high and low speeds of the vehicle. Dynamical friction models, based on the LuGre theory, are used to describe these phenomena.Then, a study of the steering model subject to the influence of exogenous inputs is done in open loop. This study shows that the steering column starts to oscillate when an exogenous input is applied. To delete low-frequency oscillations of the column, an optimal state-space control is introduced. Moreover, an observer is designed to estimate state variables of the system and exogenous inputs, acting on it.Third contribution of the thesis deals with the aim to provide some rationality to actual methods that are used to implement electronic power assistance on commercial vehicles. Indeed, investigations about actual assistance systems do not provide ground foundations or evidence that the current assistance is optimal for the driver in any sense. At this aim, an optimization procedure is proposed to retrieve the shape of the steering assistance, starting from the analysis of the steering movement, in case of a general driver's profile, and the analysis of the human perception face to an external stimulus.After that, a procedure to adapt the standard steering assistance to the driving of disabled people is proposed. As there is not any classification of drivers according to their pathology, attention focuses on drivers affected by diseases to the upper limbs that cause an asymmetry into the torque production on the steering wheels. A study about main problems that these patients are dealing during some critical driving manoeuvres is done. Starting from this, a compensation procedure is proposed to modify the standard power steering assistance. This procedure is validated in simulation. Moreover, objective evaluation criteria are derived to test improvements due to the proposed assistance.Finally, the experimental validation of all elements proposed in the general methodology is done on the tele-operation platform, present at the laboratory Gipsa-LAB. This system is made up of a control station with the operator, a pc-unit and a tele-operated vehicle, that allows retrieving a real profile of tire-road friction torque. Results about these experimental tests validate benefits of the adaptation methodology. They represent also the starting point for the installation of the proposed assistance on a real vehicle and set the basis for the application of the methodology for a wider class of patients, affected by different pathologies
AnĂĄlisis e identificaciĂłn de los factores que influyen en el incremento de la masa laminar de los tejidos de punto
[ES] Con este trabajo de fin de master se pretende examinar el comportamiento de la masa laminar de los tejidos de punto de algodĂłn, analizando algunos factores que podrĂan influir sobre las variaciones de la misma. Los datos que se utilizarĂĄn han sido registrados durante un año y algunos de los factores evaluables son el tipo de tejido, la estructura y el cĂłdigo de la tintura. A partir de estos datos y mediante el utilizo de herramientas estadĂsticas, se analizarĂĄn e identificaran los factores que mas influyen en el incremento de la masa laminar, diseñando un modelo de experimentos.Ciarla, F. (2018). AnĂĄlisis e identificaciĂłn de los factores que influyen en el incremento de la masa laminar de los tejidos de punto. http://hdl.handle.net/10251/113789TFG
Commande d'un systÚme de Puissance électrique pour personne ùgée et/ou handicapée
Nowadays, vehicles have been widely equipped with power assistance steering systems and the way of providing assist torque is various. Electronic Power Assistance Steering (EPAS) systems have the tendency to replace the Hydraulic Power Assistance Steering (HPAS) systems, due to better fuel consumption, better road feel feedback to the driver and better return-to-center performance of the steering system. Actual EPAS systems are designed basing on a general driverâs profile and they try to mimic the behavior of the HPAS system. Main goal of this thesis is to propose a general methodology to adapt standard EPAS for drivers with reduced mobility. Toward this general goal, following contributions are integrant part of this thesis.First, a mathematical model of the steering system that keeps into account the torsion of the steering column is introduced. This model is influenced by two exogenous inputs: the tire-road friction torque and the driver's torque. Mathematical models for these inputs are also proposed. Due its importance on the steering system, great attention is dedicated to the description of the tire-road friction torque. This torque includes the contribution of two main phenomena: the self-alignment and the sticking friction torques. They appear, respectively, at high and low speeds of the vehicle. Dynamical friction models, based on the LuGre theory, are used to describe these phenomena.Then, a study of the steering model subject to the influence of exogenous inputs is done in open loop. This study shows that the steering column starts to oscillate when an exogenous input is applied. To delete low-frequency oscillations of the column, an optimal state-space control is introduced. Moreover, an observer is designed to estimate state variables of the system and exogenous inputs, acting on it.Third contribution of the thesis deals with the aim to provide some rationality to actual methods that are used to implement electronic power assistance on commercial vehicles. Indeed, investigations about actual assistance systems do not provide ground foundations or evidence that the current assistance is optimal for the driver in any sense. At this aim, an optimization procedure is proposed to retrieve the shape of the steering assistance, starting from the analysis of the steering movement, in case of a general driver's profile, and the analysis of the human perception face to an external stimulus.After that, a procedure to adapt the standard steering assistance to the driving of disabled people is proposed. As there is not any classification of drivers according to their pathology, attention focuses on drivers affected by diseases to the upper limbs that cause an asymmetry into the torque production on the steering wheels. A study about main problems that these patients are dealing during some critical driving manoeuvres is done. Starting from this, a compensation procedure is proposed to modify the standard power steering assistance. This procedure is validated in simulation. Moreover, objective evaluation criteria are derived to test improvements due to the proposed assistance.Finally, the experimental validation of all elements proposed in the general methodology is done on the tele-operation platform, present at the laboratory Gipsa-LAB. This system is made up of a control station with the operator, a pc-unit and a tele-operated vehicle, that allows retrieving a real profile of tire-road friction torque. Results about these experimental tests validate benefits of the adaptation methodology. They represent also the starting point for the installation of the proposed assistance on a real vehicle and set the basis for the application of the methodology for a wider class of patients, affected by different pathologies.Ce travail de thĂšse a Ă©tĂ© effectuĂ© au sein du Laboratoire GIPSA-Lab de Grenoble, sous la direction de Carlos Canudas de Wit et co-encadrĂ© par Franck Quaine et Violaine CahouĂ«t.Ce travail a Ă©tĂ© rĂ©alisĂ© dans le cadre du projet ANR-09-VTT-14-01/06 « VOLHAND ». Il sâinscrit dans le contexte gĂ©nĂ©ral des nouvelles gĂ©nĂ©rations de Direction AssistĂ©e Electrique (DAE, ou EPAS en anglais pour Electronic Power Assistance Steering) avec pour objectif spĂ©cifique de tenir compte des caractĂ©ristiques des conducteurs Ă mobilitĂ© rĂ©duite. En effet, Ă ce jour, il nâexiste pas de systĂšme de direction assistĂ©e adaptĂ© aux capacitĂ©s articulaires (rhumatismes divers), musculaires (diminution de force, sĂ©nescence), ou encore aux douleurs ressenties par le conducteur. Le principal objectif de cette thĂšse est donc de proposer une mĂ©thodologie gĂ©nĂ©rale permettant d'adapter une DAE standard aux conducteurs Ă mobilitĂ© rĂ©duite. Le mĂ©moire est organisĂ© en cinq chapitres.Chapitre 1, intitulĂ© Context and objectives of the study presente lâimpact Ă©conomique et sociĂ©tal, la problĂ©matique et lâobjectif. Ensuite, la stratĂ©gie permettant dâatteindre lâobjectif ainsi spĂ©cifiĂ© est prĂ©cisĂ©e.Chapitre 2, intitulĂ© Models for simulation, est dĂ©diĂ© Ă lâĂ©tablissement dâun modĂšle mathĂ©matique du systĂšme de DAEs prenant bien en compte lâĂ©lasticitĂ© en torsion de la colonne de direction due Ă la prĂ©sence dâun capteur de couple. Parmi les entrĂ©es de ce modĂšle Ă deux degrĂ©s de libertĂ©, une attention est faite en ce qui concerne la description du couple de frottement du contact pneumatique-route. Un modĂšle de frottement dynamique, basĂ© sur le modĂšle de LuGre, est dĂ©veloppĂ© pour dĂ©crire ces phĂ©nomĂšnes. Une amĂ©lioration du modĂšle est ainsi proposĂ©e.Chapitre 3, intitulĂ© Oscillation annealing and torque observer design, commence par mettre en Ă©vidence les consĂ©quences de la prĂ©sence du mode souple associĂ© Ă lâĂ©lasticitĂ© en torsion du capteur de couple sur le ressenti au niveau du volant. Une commande LQ est proposĂ©e pour limiter les oscillations dues Ă ce mode souple. Enfin, un observateur pour estimer le couple conducteur et le couple rĂ©sultant du frottement pneumatique route est dĂ©veloppĂ©.Chapitre 4, intitulĂ© Power steering booster stage, se focalise dans un premier temps sur la nature des courbes dâassistance utilisĂ©es dans le cadre des DAE. En effet, lâĂ©tat de lâart sur le sujet met en Ă©vidence lâabsence de justification de la forme de ces courbes gĂ©nĂ©ralement fonction de la vitesse du vĂ©hicule et du couple appliquĂ© par le conducteur. Dans ce chapitre on propose de calculer de nouvelles lois en se fondant sur lâapproche par optimisation (minimisation du jerk couplĂ© avec la loi de puissance de Steven). Les rĂ©sultats obtenus montrent que la minimisation du critĂšre fondĂ© sur le jerk du volant et la loi de puissance de Steven peut permettre de reproduire les lois existantes dâassistance et leur apportent une justification. Ils confirment Ă©galement la forte influence du frottement (couple) au niveau du contact roue-sol. La seconde partie de ce chapitre est consacrĂ©e au dĂ©veloppement dâune mĂ©thodologie gĂ©nĂ©rale dâadaptation des lois dâassistance (cartographie standard initiale) aux exigences du conducteur Ă mobilitĂ© rĂ©duite (typiquement ici une personne prĂ©sentant une asymĂ©trie.Chapitre 5, intitulĂ© Experimental validation NeCS-Car benchmark, commence par dĂ©tailler la plateforme expĂ©rimentale prĂ©sente au laboratoire GIPSA-LAB et utilisĂ©e pour Ă©valuer et valider les nouvelles lois dâassistance adaptĂ©es au conducteur Ă mobilitĂ© rĂ©duite. La stratĂ©gie globale dâassistance de couple au volant pour un conducteur prĂ©sentant une asymĂ©trie, est testĂ©e sur le banc avec la NeCS-Car. Les rĂ©sultats issus du protocole montrent la validitĂ© de la stratĂ©gie proposĂ©e.Ce mĂ©moire se termine avec une partie General conclusions and perspectives oĂč les principales contributions sont dâabord rappelĂ©es, puis oĂč des perspectives pour complĂ©ter et prolonger ce travail sont proposĂ©es
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