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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Modélisation et analyses cinématiques de l'épaule lors de levers de charges en hauteur

Desmoulins, Landry 10 1900 (has links)
Thèse de doctorat à mi-chemin entre la recherche fondamentale et appliquée. Les champs disciplinaires sont principalement la biomécanique, l'ergonomie physique ou encore l'anatomie. Réalisé en cotutelle avec le professeur Paul Allard et Mickael Begon. / An occupation that requires handling loads combined with large elevation of the arms is associated with the occurrence of shoulders musculoskeletal disorder. The analysis of these joint movements is essential because it helps to quantify the stress applied to the musculoskeletal structures. This thesis provides an innovative model which allows the estimation of the shoulder complex kinematics and used it to analyze the joints kinematics during lifting tasks. It is organized into three sub-objectives. The first aim is the development and validation of a kinematic model the most representative as possible of the shoulder complex anatomy while correcting soft tissue artifacts through the use of global optimization. This model included a scapulothoracic closed loop, which constrains a scapular dot contact to be coincident with thoracic gliding plane modeled by a subject-specific ellipsoid. In the validation process, the reference model used the gold standard for direct measurements of bone movements. In dynamic movements, the closed loop model developed generates barely more kinematic errors that errors obtained for the study of standard movements by existing models. The second aim is to detect and quantify the shoulder articular movements influenced by the combined effects of two risk factors: task height and load weight. The results indicate that many peaks of joint angles are influenced by the interaction of height and weight. According to the different initial and deposits heights when the weight increases, the kinematics changes are substantial, in number and magnitude. The kinematic strategies of participants are more consistent when the weight of load increase for initial height lift at hips level compared to shoulders level, and for a deposit at eye level compared to shoulders. The third aim is to investigate the magnitude and temporality of the maximum peak vertical acceleration of the box. The significant joints movements are characterized with a principal component analysis of joint angle values collected at this instant. In particular, this study highlights that elbow flexion and thoraco-humeral elevation are two correlated invariant joint movements to all lifting tasks whatever the initial and deposit height, and weight of the load. The realism of the developed shoulder model and kinematics analyzes open perspectives in occupational biomechanics and contribute to risk prevention efforts in health and safety. / Une activité professionnelle qui exige de manipuler des charges combinée à de grandes élévations des bras augmente les chances de développer un trouble musculo-squelettique aux épaules. L’analyse de ces mouvements articulaires est essentielle car elle contribue à quantifier les contraintes appliquées aux structures musculo-squelettiques. Cette thèse propose un modèle innovant qui permet l’estimation de la cinématique du complexe de l’épaule, et l’utilise ensuite afin d’analyser la cinématique de levers de charge. Elle s’organise en trois sous-objectifs. Le premier concerne le développement et la validation d’un modèle cinématique le plus représentatif possible de l’anatomie du complexe de l’épaule tout en corrigeant les artéfacts des tissus mous par une optimisation multi-segmentaire. Ce modèle avec une fermeture de boucle scapulo-thoracique, impose à un point de contact scapulaire d’être coïncident au plan de glissement thoracique modélisé par un ellipsoïde mis à l’échelle pour chaque sujet. Le modèle qui a été utilisé comme référence lors des comparaisons du processus de validation bénéficie du « gold standard » de mesures directes des mouvements osseux. Le modèle développé en boucle fermée génère à peine plus d’erreurs cinématiques lors de mouvements dynamiques que les erreurs obtenues par les modèles existants pour l’étude de mouvements standards. Le second identifie et quantifie les mouvements articulaires de l’épaule influencés par la combinaison des effets de deux facteurs de risques : les hauteurs importantes d’agencement de la tâche (hauteurs de saisie et de dépôt) et les masses de charges (6 kg, 12 kg et 18 kg). Les résultats indiquent qu’il existe de nombreux pics d’angles articulaires qui sont influencés par l’interaction des deux effets. Lorsque la masse augmente, les modifications cinématiques sont plus importantes, en nombre et en amplitude, selon les différentes hauteurs de saisies et de dépôts de la charge. Les participants varient peu leur mode opératoire pour une saisie à hauteur des hanches en comparaison des épaules, et pour un dépôt à hauteur des yeux en comparaison aux épaules avec une charge plus lourde. Un troisième s’intéresse au pic maximal d’accélération verticale de la charge dans son intensité et sa temporalité. Basée sur une analyse en composante principale des valeurs d’angles articulaires à cet instant, elle permet de caractériser les mouvements articulaires significatifs. Cette étude met notamment en évidence que la flexion du coude et l’élévation thoraco-humérale sont deux mouvements articulaires corrélés invariants à toutes les tâches de lever en hauteur quelles que soient la hauteur de dépôt et la masse de la charge. Le souci de réalisme du modèle développé et les analyses cinématiques menées ouvrent des perspectives en biomécanique occupationnelle et participent à l’effort de prévention des risques en santé et sécurité.
412

Vybrané otázky překonávání majetkové samostatnosti kapitálových společností ve srovnávacím pohledu / Piercing the Corporate Veil - Selected Issues in International Comparison

Kostohryz, Milan January 2012 (has links)
Milan Kostohryz Piercing the Corporate Veil - Selected Issues in International Comparison Abstract The main purpose of the thesis is to give recommendation for possible application of the piercing doctrine in the Czech Republic. Secondary purposes are (i) analysis of effects caused by disregarding the principles of limited liability and separate legal personality because of piercing and (ii) detailed description of approaches to the piercing issue in selected legal systems (USA, UK and Germany). The thesis starts with some terminological issues; it introduces the possible Czech equivalents of the notion "piercing the corporate veil" and explains that it can have slightly different meaning depending on the individual author. The differences stem especially from the questions whether piercing negates only the principle of limited liability or also the principle of separate personality; whether so called inner piercing (Innenhaftung) shall be part of the doctrine and whether the piercing doctrine shall be regarded as product of case-law only. Also some special forms of piercing (reverse piercing, lateral piercing and insider piercing) are introduced. The third chapter analyses the relationship between the piercing doctrine and the principles of limited liability and separate legal personality. In particular it...
413

Design and control of collaborative, cross and carry mobile robots : C3Bots / Conception et commande des robots mobiles, manipulateurs, collaboratifs et tous terrains

Hichri, Bassem 05 October 2015 (has links)
L'objectif du travail proposé est de concevoir et commander un groupe des robots mobiles similaires et d'architecture simple appelés m-bots (mono-robots). Plusieurs m-bots ont la capacité de saisir ensemble un objet afin d'assurer sa co-manipulation et son transport quelle que soit sa forme et sa masse. Le robot résultant est appelé p-bot (poly-robot) et est capable d'effectuer des tâches de déménageur pour le transport d'objets génériques. La reconfigurabilité du p-bot par l'ajustement du nombre des m-bots utilisés permet de manipuler des objets lourds et des objets de formes quelconques (particulièrement s'ils sont plus larges qu'un seul m-bot). Sont considérés dans ce travail l'évitement d'obstacle ainsi que la stabilité du p-bot incluant la charge à transporter. Une cinématique pour un mécanisme de manipulation a été proposée et étudiée. Ce dernier assure le levage de la charge et son dépôt sur le corps des robots pour la transporter. Plusieurs variantes d'actionnement ont été étudiées : passif, avec compliance et actionné. Un algorithme de positionnement optimal des m-bots autour de l'objet à manipuler a été proposé afin d'assurer la réussite de la tâche à effectuer par les robots. Cet algorithme respecte le critère de "Force Closure Grasping" qui assure la stabilité de la charge durant la phase de manipulation. Il maintient aussi une marge de stabilité statique qui assure la stabilité de l'objet durant la phase de transport. Enfin, l'algorithme respecte le critère des zones inaccessibles qui ne peuvent pas être atteintes par les m-bots. Une loi de commande a été utilisée afin d'atteindre les positions désirées pour les m-bots et d'assurer la navigation en formation, durant la phase du transport, durant laquelle chaque robot élémentaire doit maintenir une position désirée par rapport à l'objet transporté. Des résultats de simulation pour un objet de forme quelconque, décrite par une courbe paramétrique, sont présentés. Des simulations 3D en dynamique multi-corps ainsi que des expériences menées sur les prototypes réalisés ont permis de valider nos propositions. / Our goal in the proposed work is to design and control a group of similar mobile robots with a simple architecture, called m-bot. Several m-bots can grip a payload, in order to co-manipulate and transport it, whatever its shape and mass. The resulting robot is called a p-bot andis capable to solve the so-called "removal-man task" to transport a payload. Reconfiguring the p-bot by adjusting the number of m-bots allows to manipulate heavy objects and to manage objects with anyshape, particularly if they are larger than a single m-bot. Obstacle avoidance is addressed and mechanical stability of the p-bot and its payload is permanently guaranteed. A proposed kinematic architecture for a manipulation mechanism is studied. This mechanism allows to lift a payload and put it on them-bot body in order to be transported. The mobile platform has a free steering motion allowing the system maneuver in any direction. An optimal positioning of the m-bots around the payload ensures a successful task achievement without loss of stability for the overall system. The positioning algorithm respects the Force Closure Grasping (FCG) criterion which ensures the payload stability during the manipulation phase. It respects also the Static Stability Margin (SSM) criterion which guarantees the payload stability during the transport. Finally, it considers also the Restricted Areas (RA) that could not be reached by the robots to grab the payload. A predefined control law is then used to ensure the Target Reaching (TR) phase of each m-bot to its desired position around the payload and to track a Virtual Structure (VS), during the transportation phase, in which each elementary robot has to keep the desired position relative to the payload. Simulation results for an object of any shape, described by aparametric curve, are presented. Additional 3D simulation results with a multi-body dynamic software and experiments by manufactured prototypes validate our proposal.
414

金融集團業務經營之法律問題-以關係人交易規範為中心 / A study of regulation of financial business -based on related party transaction

朱美蓮 Unknown Date (has links)
金融機構所經營之業務涵蓋種類繁多、型式各異並各有其相關之法令,而金融機構透過直接或間接投資方式,一般而言將構成金融集團間之關係人及其交易,本論文之目的在於分析各種金融集團關係人交易相關法令之缺漏,並進而提出建議。 本文首先從現行金融機構經營及投資規範及金融機構關係人交易法律規範,歸納整理出相關法規機制,並探討現行該等關係人及交易之法律規範之「過」與「不足」之處。 此外,本文也參考美國法及跨國性金融監理機構之相關規範,藉此與我國相關規範比較,以作為我國相關立法之參考方向。 接著,本文再以金融機構關係人之實際相關案例,深入分析本國實務上常見之問題,以探討實務上對關係人的認定標準,並釐清現行金融監理對關係人間非常規交易之管理缺漏。 最後本文以上述之分析結果,提出對現行金融機構關係人相關法規之建議,以提供未來修法之參考。 / Due to deregulation and globalization in banking system, financial institutions are increasingly burring traditional differences between banking, insurance, and other institutions. As results, intra-group transactions cause more concern about the conflicts of interests. From a legal point of view, different legal relationships will confer different rights and impose different duties on financial parties. Therefore, it is sensible to analyze the legal nature of the relationships of different participants and their roles in financial institutions’ related party transactions. This study presents an analysis of regulations of related party transactions within Financial Conglomerates, and proposes reforms to deal with conflicts of interest: Firstly, discusses the regulations about the business scope of financial holding company, bank, securities and insurance company. Then further analyzes the regulations of related party transactions within each above financial parties. Secondly, depicts the American regulatory scheme and the frames guidelines and principles of international financial supervisory institutions. The former focuses on the background of banking regulations and the latest issue about The Dodd-Frank Act. The later includes the Basel Committee on Banking Supervision (BCBS), the International Organization of Securities Commissions (IOSCO), the International Association of Insurance Supervisors (IAIS), the International Swaps and Derivatives Association (ISDA) and the Joint Forum on Financial Conglomerates. A comparative analysis of regulations of the above and Taiwan was made. Thirdly, further analyzes the controversial issues of intra-group transactions based on several judicial cases, and then discusses the operational deficiencies of financial institutions and flaws of law and regulations. Finally, summarizes the said issues and propositions about related party transactions of financial institutions.
415

Los grupos de empresa y la relación individual de trabajo en el marco de una economía productiva descentralizada

Jiménez Rojas, Francisco 30 March 2012 (has links)
La organización productiva descentralizada y flexible que, bajo el impulso de las nuevas tecnologías y la globalización, viene sustituyendo a partir del último cuarto del siglo XX al fordismo de inspiración keynesiana, está deteriorando los mercados laborales, lo que supone una precarización de las condiciones de empleo, un notable repliegue de los «Estados del bienestar» y la desactivación del factor trabajo. Superado el tradicional principio de «unicidad» empresarial, un empresario «complejo» y múltiple –el grupo de empresas-, caracterizado por su dificultad identificatoria, absorbe un protagonismo creciente, en un contexto normativo-laboral casi desregulado, en el que al margen del fraude, la dirección unitaria de las empresas agrupadas no implica deducir de su funcionamiento una responsabilidad (solidaria). En esa «cierta unidad económica» que constituye el grupo, se detecta un punto de conflicto o desconexión, entre las facultades empresariales decisorias -unidad de decisión- y las organizativas –dependencia y ajenidad de frutos-. / The decentralized and flexible productive organization, boosted by globalization, new information and knowledge technologies, has been replacing the Fordist Keynesian inspiration since the last quarter of the 20th century; besides it has been worsening the labour markets, which involves a precariousness of employment conditions and an outstanding backing down of “welfare states” and job factor neutralization. Once the traditional principle of business uniqueness has been overwhelmed, a complex and multiple –the corporate group- employer arises; this employer is characterized by the difficulty of being identified and acquires an increasingly featuring role, inside a regulatory working context almost deregulated, where, on the fringe fraud, the unitarian corporate group management doesn’t imply deducing a solidarity liability from its activity. Inside that “particular economical unity” made up by the group, a deal-breaker or a gap is detected between the decision-making management faculties –decision unity- and the organizational ones –dependence and another person’s benefits-.
416

Étude de la réponse dynamique des ponts roulants soumis à des chocs multiples pendant un séisme : Co-simulation implicite / explicite multi-échelle en temps pour la dynamique du contact / Numerical response of bridge cranes subjected to repeated shocks during an earthquake : Implicit / explicite multi-time scale co-simulation for contact dynamics

Fekak, Fatima-Ezzahra 02 May 2017 (has links)
Les ponts roulants sont des engins de levage situés en haut des bâtiments qu'ils équipent. Ils servent à manutentionner des charges très lourdes et parfois critiques. Pendant un séisme, un pont roulant est exposé à des chocs multiples. Ces impacts peuvent causer des dommages importants dans la structure pouvant conduire à une chute de la charge manutentionnée ou du pont roulant lui-même. Donc, la vérification de la tenue des ponts roulants au séisme est une question primordiale. Actuellement, cette vérification est basée sur des méthodes de calcul statiques. Ces méthodes font l'hypothèse d'un comportement purement linéaire des ponts roulants ce qui les rend très conservatives. Depuis quelques années les niveaux sismiques imposés par les autorités nationales augmentent chaque année, et les constructeurs de ponts roulants se trouvent dans l'incapacité de construire à partir des efforts sur-estimés fournis par les méthodes statiques. L'objectif de la thèse est l'étude de la réponse dynamique d'un pont roulant pendant un séisme en prenant en compte les non-linéarités géométriques et matériau. Afin de modéliser ces phénomènes, une analyse dynamique temporelle avec une approche multi-échelle en temps est adoptée. Pour prendre en compte l'aspect haute fréquence des chocs, un intégrateur temporel variationnel explicite, basé sur la méthode des multiplicateurs de Lagrange et dédié au contact/impact, est développé. Ensuite, un intégrateur hétérogène (différents schémas d'intégration) asynchrone (différents pas de temps), basé sur la méthode de couplage GC, est appliqué au problème du pont roulant. Cette stratégie multi-échelle en temps permet d'adapter le schéma d'intégration et le pas de temps au sous domaine considéré. Par conséquent, l'intégrateur explicite est adopté dans les zones de contact et un schéma implicite de type accélération moyenne, est adopté dans le reste de la structure. Finalement, un démonstrateur de co-simulation entre les logiciels Cast3M et Europlexus est mis en place pour montrer le gain très significatif en temps de calcul dans le cas d'un modèle élément finis tridimensionnel d'un pont roulant industriel. / Bridge cranes are hoisting appliances located overhead in buildings. They are used to handle very heavy and sometimes critical loads. During an earthquake, a bridge crane may be subjected to multiple impacts between wheels and rails. These impacts can cause significant damage to the structure leading to a fall of the handled load or the bridge crane itself. Therefore, the qualification of such equipment, subjected to an earthquake, is very important. Currently, this qualification is based on static methods. These methods assume a purely linear behavior of the bridge cranes, which leads to a very conservative forces. Consequently, the bridge cranes manufacturers are sometimes unable to design the equipement from the over-estimated efforts provided by the static methods. The aim of this work is to study the dynamic response of a bridge crane during an earthquake by taking into account the geometric and material non-linearities. In order to model such phenomena, a time-history dynamic analysis with a multi-scale approach is performed. To take into account the high frequency aspect of the impacts between wheels and rails, a Lagrange explicit contact/impact time integrator is proposed. This work has also led to the development of an explicit–implicit HATI (Heterogeneous Asynchronous Time Integrator) for contact/impact dynamics. This method allows us to adopt an explicit contact/impact time integrator in the contact area and an implicit time integrator with a coarse mesh in the rest of the domain. Finally, a co-simulation demonstrator between Cast3M and Europlexus softwares is set up to show the very significant gain in computation time for a three-dimensional finite element model of an industrial bridge crane.
417

Estudo e especifica??o de um sistema de instrumenta??o para unidades de eleva??o de petr?leo utilizando tecnologia sem fio

Campos, Carlo Frederico Pereira de Siqueira 27 November 2006 (has links)
Made available in DSpace on 2014-12-17T14:56:21Z (GMT). No. of bitstreams: 1 CarloFPSC.pdf: 941846 bytes, checksum: 5fe2e2c9851039018a0653de693d001c (MD5) Previous issue date: 2006-11-27 / Wireless sensor networks are reality nowadays. The growing necessity of connectivity between existing industrial plant equipments pushes the research and development of several technologies. The IEEE 802.15.4 LR-WPAN comes as a low-cost and powersaving viable solution, which are important concerns while making decisions on remote sensoring projects. This study intends to propose a wireless communication system which makes possible the monitoring of analogic and/or digital variables (i. e., the pressure studied) involved on the artificial methods for oil and gas lifting. The main issues are: To develop a software based on SMAC Standard in order to create a wireless network to monitoring analogic and/or digital variables; To evaluate the communication link based on the number of lost packets tested in different environments (indoor and outdoor) and To propose an instrumentation system consisting of wireless devices / As redes de sensores sem fio (RSSS) j? s?o uma realidade hoje em dia, pois a grande necessidade de conectividade entre os equipamentos existentes numa planta industrial impulsiona a pesquisa e o desenvolvimento de diversas tecnologias. O padr?o LR-WPAN IEE 802.15.4 apresenta-se como uma solu??o vi?vel, com baixo custo e baixo consumo de energia, requisitos importantes para a implanta??o de um sistema de sensoriamento remoto. A contribui??o deste trabalho consiste em propor um sistema de comunica??o sem fio, que possa monitorar vari?veis anal?gicas e/ou digitais (no caso do estudo em quest?o, a press?o) nos m?todos de eleva??o artificial de petr?leo e g?s natural. Os pontos principais deste estudo s?o: Desenvolver um software baseado no Padr?o SMAC com intuito de criar uma rede sem fio com fins de monitoramento de vari?veis anal?gicas e/ou digitais; Avaliar o enlace de comunica??o com rela??o a quantidade de pacotes perdidos em diferentes ambientes (ambientes internos (Indoor) e externos (Outdoor)) e, Propor um sistema de instrumenta??o utilizando tecnologia sem fio
418

Controle autom?tico para inje??o otimizada de g?s em po?os de petr?leo equipados para funcionamento com g?s lift cont?nuo

Spindola, Rafael Barbosa 16 July 2003 (has links)
Made available in DSpace on 2014-12-17T14:56:21Z (GMT). No. of bitstreams: 1 RafaelBS.pdf: 1607732 bytes, checksum: d5ad875fd4dc09637b9932966f4df8c0 (MD5) Previous issue date: 2003-07-16 / The continuous gas lift method is the main artificial lifting method used in the oil industry for submarine wells, due to its robustness and the large range of flow rate that the well might operate. Nowadays, there is a huge amount of wells producing under this mechanism. This method of elevation has a slow dynamics due to the transients and a correlation between the injected gas rate and the of produced oil rate. Electronics controllers have been used to adjust many parameters of the oil wells and also to improve the efficiency of the gas lift injection system. This paper presents a intelligent control system applied to continuous gas injection in wells, based in production s rules, that has the target of keeping the wells producing during the maximum period of time, in its best operational condition, and doing automatically all necessary adjustments when occurs some disturbance in the system. The author also describes the application of the intelligent control system as a tool to control the flow pressure in the botton of the well (Pwf). In this case, the control system actuates in the surface control valve / O m?todo de eleva??o por g?s lift cont?nuo ? o principal m?todo de eleva??o artificial utilizado, principalmente, para produ??o em po?os submarinos devido a sua robustez e a larga faixa de vaz?o que o po?o pode produzir. H? um grande percentual de po?os produzindo sob este mecanismo no Brasil. Este tipo de m?todo de eleva??o apresenta algumas caracter?sticas pr?prias, sendo uma delas sua din?mica lenta devido aos transientes e outra ? a exist?ncia de uma correla??o entre a vaz?o de g?s injetado e a vaz?o de ?leo produzido. Controladores eletr?nicos t?m sido utilizados para realizar ajustes em alguns par?metros do po?o e melhorar a efici?ncia de inje??o de g?s lift. Este trabalho apresenta um sistema inteligente de controle autom?tico da inje??o de g?s, baseando-se em regras de produ??o, que busca manter os po?os equipados para g?s lift cont?nuo produzindo o maior tempo poss?vel, nas condi??es ?timas de opera??o e que faz os ajustes autom?ticos necess?rios quando ocorre alguma perturba??o no sistema. Mostra-se que ? poss?vel, utilizando o sistema inteligente apresentado, exercer o controle da press?o de fluxo no fundo do po?o (Pwf) atrav?s da manipula??o da abertura da v?lvula de controle de superf?cie
419

Assessment and design of industrial manual handling to reduce physical ergonomics hazards : – use and development of assessment tools

Lind, Carl January 2017 (has links)
Despite efforts of reducing harmful physical ergonomics exposures related to manual handling, the occurrence of heavy or repetitive manual handling, and non-neutral postures is high in many occupational sectors. To reduce these exposures, interventions and job design strategies can utilize risk assessment. A need was identified of an observation-based tool which supported occupational health and safety practitioners for assessments of risk factors related to manual handling. The aim of this thesis was to explore the use and important usability-related aspects of observation-based assessment tools among professional ergonomists, and to develop new research based assessment and screening tools, to present their scientific basis and to evaluate their reliability and usability. A web-based questionnaire was employed to gain knowledge on the use and usability aspects of risk assessment tools among ergonomists in Sweden. The assessment tools RAMP I and RAMP II were developed in an iterative process, including literature searches, expert group judgments, and with input from more than 80 practitioners. The reliability and usability evaluations included assessments and ratings by practitioners. The thesis points to a low use of several internationally spread assessment tools among Swedish ergonomists, and a relatively higher use of tools promoted by the Swedish Work Environment Authority. Several usability-related aspects were identified as important, such as being easy and quick to use, its ability to communicate and visualize the results, and its ability to facilitate improvement measures. The developed tools support assessment of a broad range of risk factors related to manual handling. The thesis supports that assessments with acceptable reliability can be achieved for the majority of items of the two developed tools. The thesis supports that the tools are usable in supporting risk assessments targeting risk factors related to industrial manual handling. / Trots ansträngningar för att minska belastningsergonomiska exponeringar relaterade till manuell hantering är förekomsten av exponering av riskkällor såsom tung eller repetitiv manuell hantering, obekväma arbetsställningar, hand–armvibrationer och helkroppsvibration omfattande inom flera sektorer. Dessa belastningsergonomiska exponeringar tros i betydande utsträckning bidra till en stor andel av arbetsrelaterade muskuloskeletala besvär och arbetssjukdomar inom flera sektorer som exempelvis tillverkningsindustrin. Riskbedömningar kan användas inom det förebyggande arbetet kopplat till interventioner eller arbetsutformning för att minska dessa skadliga exponeringar (risk faktorer), vilket även är ett krav om arbetet innefattar manuell hantering eller andra riskkällor. Trots det stora antalet observationsbaserade bedömningsverktyg utvecklade för att stödja riskbedömningar av arbete som innefattar manuell hantering identifierades ett behov av ett nytt observationsbaserat bedömningsverktyg som stödjer praktiker i utförliga bedömningar av flertalet riskfaktorer relaterade till manuell hantering och som ger stöd i det systematiska arbetsmiljöarbetet. Syftet med avhandlingen är att utforska användningen av, och viktiga användbarhetsrelaterade aspekter av observationsbaserade bedömningsverktyg bland professionella ergonomer som arbetar i Sverige. Dessutom är syftet även att utveckla nya forskningsbaserade screeningverktyg och bedömningsverktyg, presentera deras forskningsbas samt att utvärdera deras reliabilitet och användbarhet. En webbaserad enkät användes för att inhämta kunskap om i vilken omfattning dessa verktyg används av professionella ergonomer och vilka användbarhetsrelaterade aspekter som ansågs särskilt betydelsefulla för dessa verktyg. För att utveckla de nya verktygen (dvs. RAMP I och RAMP II) genomfördes litteratursökningar för att identifiera kvantitativt beskrivna riskfaktorer relaterade till manuell hantering och betydelsefulla faktorer som påverkar arbetstagares kapacitet vid manuell hantering. Verktygen utvecklades i en iterativ process med input från mer 80 praktiker, varav mer än 30 professionella ergonomer, samt expertgruppsbedömning. De två verktygen utvärderades med avseende deras interbedömarreliabilitet utifrån bedömningar genomförda av ergonomer och ingenjörer/tekniker utifrån videofilmade arbeten inom industriell manuell hantering. Verktygens användbarhet utvärderas av 20 praktiker med en pappersenkät och verktygens ’användarvänlighet’ av 22 ergonomer. Avhandlingen pekar på en relativt låg proportionell användning av flera internationellt spridda bedömningsverktyg bland professionella ergonomer som arbetar i Sverige, och en relativt hög proportionell användning av bedömningsverktyg som stöds av Arbetsmiljöverket. Flera användbarhetsrelaterade aspekter identifierades som betydelsefulla bland ergonomerna, i synnerhet betydelsen av att bedömningsverktygen är enkla och snabba att använda, deras förmåga att kommunicera och visualisera resultatet av bedömningar, och deras förmåga att stödja åtgärdsarbetet. Det utvecklade screeningverktyget och bedömningsverktyget stödjer bedömning av flertalet riskfaktorer relaterade till industriell manual hantering. Avhandling ger stöd att majoriteten av verktygens bedömningspunkter har acceptabel interbedömarreliabilitet och förbättringsområden för verktygen har identifierats. Avhandling ger stöd att de två utvecklade verktygen är användbara vid riskbedömningar av belastningsergonomiska riskfaktorer relaterade till industriell manual hantering. / <p>QC 20170510</p>
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On the design of fast and efficient wavelet image coders with reduced memory usage

Oliver Gil, José Salvador 06 May 2008 (has links)
Image compression is of great importance in multimedia systems and applications because it drastically reduces bandwidth requirements for transmission and memory requirements for storage. Although earlier standards for image compression were based on the Discrete Cosine Transform (DCT), a recently developed mathematical technique, called Discrete Wavelet Transform (DWT), has been found to be more efficient for image coding. Despite improvements in compression efficiency, wavelet image coders significantly increase memory usage and complexity when compared with DCT-based coders. A major reason for the high memory requirements is that the usual algorithm to compute the wavelet transform requires the entire image to be in memory. Although some proposals reduce the memory usage, they present problems that hinder their implementation. In addition, some wavelet image coders, like SPIHT (which has become a benchmark for wavelet coding), always need to hold the entire image in memory. Regarding the complexity of the coders, SPIHT can be considered quite complex because it performs bit-plane coding with multiple image scans. The wavelet-based JPEG 2000 standard is still more complex because it improves coding efficiency through time-consuming methods, such as an iterative optimization algorithm based on the Lagrange multiplier method, and high-order context modeling. In this thesis, we aim to reduce memory usage and complexity in wavelet-based image coding, while preserving compression efficiency. To this end, a run-length encoder and a tree-based wavelet encoder are proposed. In addition, a new algorithm to efficiently compute the wavelet transform is presented. This algorithm achieves low memory consumption using line-by-line processing, and it employs recursion to automatically place the order in which the wavelet transform is computed, solving some synchronization problems that have not been tackled by previous proposals. The proposed encode / Oliver Gil, JS. (2006). On the design of fast and efficient wavelet image coders with reduced memory usage [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1826 / Palancia

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