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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.
341

Large scale group network optimization

Shim, Sangho 17 November 2009 (has links)
Every knapsack problem may be relaxed to a cyclic group problem. In 1969, Gomory found the subadditive characterization of facets of the master cyclic group problem. We simplify the subadditive relations by the substitution of complementarities and discover a minimal representation of the subadditive polytope for the master cyclic group problem. By using the minimal representation, we characterize the vertices of cardinality length 3 and implement the shooting experiment from the natural interior point. The shooting from the natural interior point is a shooting from the inside of the plus level set of the subadditive polytope. It induces the shooting for the knapsack problem. From the shooting experiment for the knapsack problem we conclude that the most hit facet is the knapsack mixed integer cut which is the 2-fold lifting of a mixed integer cut. We develop a cutting plane algorithm augmenting cutting planes generated by shooting, and implement it on Wong-Coppersmith digraphs observing that only small number of cutting planes are enough to produce the optimal solution. We discuss a relaxation of shooting as a clue to quick shooting. A max flow model on covering space is shown to be equivalent to the dual of shooting linear programming problem.
342

Les ondelettes comme fonctions de base dans le calcul de structures électroniques

Chauvin, Claire 14 November 2005 (has links) (PDF)
Cette thèse est consacrée à la définition et la mise en oeuvre d'une méthode multirésolution pour le calcul de la structure électronique d'un système composé de plusieurs noyaux et d'électrons. Dans le cadre de ce travail, nous nous intéressons à la Théorie de la Fonctionnelle de la Densité, dans laquelle le potentiel agissant sur chaque orbitale est exprimé via la densité électronique, selon un terme coulombien et un terme non linéaire. La détermination de l'état fondamental conduit au système d'équations de Kohn et Sham. La forme du potentiel de l'opérateur hamiltonien est décrite dans le chapitre deux. La résolution numérique requiert des fonctions de base possédant de bonnes propriétés physiques et algorithmiques. Les deux familles de bases couramment utilisées ne permettent pas simultanément de construire une base adaptée au système physique et de résoudre efficacement le problème auto-cohérent. C'est pourquoi l'on s'intéresse dans cette thèse à des bases d'ondelettes orthogonales et biorthogonales, et à leurs propriétés vis-à-vis du problème d'interpolation, que l'on présente dans le chapitre trois. Dans le chapitre suivant on détermine le potentiel coulombien en résolvant l'équation de Poisson, par des algorithmes itératifs utilisant le préconditionnement du laplacien en base d'ondelettes, et une méthode multigrille. On détaille ensuite la discrétisation du système d'équations par une méthode combinant formulation de Galerkin et méthode de collocation. On analyse enfin l'ordre de l'approximation pour l'oscillateur harmonique et l'hydrogène, et le comportement du système autocohérent pour différents systèmes physiques.
343

Utveckling av ett lyftverktyg för skivformade produkter / Development of a vacuum lifter for sheet materials

Andersson, Louise, Erlandsson, Stefan January 2014 (has links)
Under höstterminen 2013 har Stefan Erlandsson och Louise Andersson, designingenjörsstudenter på Högskolan i Skövde, utfört ett produktutvecklingsprojekt i samarbete med entreprenören Lars Willebrand. Målsättningen för projektet var att utveckla ett lyftverktyg som ska komplettera Willebrands produktserie bestående av; travers, svängkran, plåtbyrå och lyftverktyg. Lyftverktyget ska vara anpassat för att användas i kombination med en plåtbyrå, vilket innebär att det kommer användas till att lyfta material från höga och låga höjder. Lyftverktyget måste därmed konstrueras i syfte att underlätta för användaren och undvika arbetsskador som kan uppstå vid dessa lyft. Lyftverktyget ska även kunna anpassas till kunder som endast avser att lyfta skivformade produkter i midjehöjd. Projektet inleds med en förstudie där mycket fokus läggs på ergonomi och användaren. Förstudien har gjorts genom fördjupning i relevant litteratur, kontakt med industriföretag och genom att analysera konkurrerande lyftverktyg. Resultatet från förstudien har sammanfattats till en kravspecifikation som legat till grund för konceptframtagningen. Konceptframtagningen har skett stegvis, där lyftverktygets huvudfunktioner utvecklats var för sig. De funktioner som utvecklats är justering av sugkopparnas position, manövrering och lyft vid hög/låg höjd. Alternativa lösningar har tagits fram och utvärderats för att hitta den lämpligaste lösningen på varje enskild funktion. När de bästa lösningarna hade tagits fram sattes dessa samman till ett slutgiltigt koncept. Det slutgiltiga konceptet har analyserats och detaljutvecklats. För att underlätta tillverkning och tillgodose kundens behov har många av lyftverktygets delar anpassats och ritats om. För att säkerställa att lyftverktyget lever upp till kravspecifikationen har hållfasthetsberäkningar och en antropometrisk analys genomförts. Projektets process och resultat sammanfattades och diskuterades. Slutligen gavs förslag på rekommendationer för fortsatt utveckling av lyftverktyget. / During the second semester of 2013, product design engineering students Stefan Erlandsson and Louise Andersson have been involved in a project in cooperation with entrepreneur Lars Willebrand. The main objective of this project has been to develop a lifting tool for sheet materials. The lifting tool is one of four different products developed by Lars Willebrand. The line of products also includes an overhead crane, a slewing crane and a storage drawer for metal sheets, which are already fully developed and ready for production. The purpose of this lifting tool is to be used along with the storage drawer which means that is has to be optimised for lifting sheet materials from different heights. This means that the lifting tool has to be designed with regards to the users working postures. Human factors such as ergonomics have to be taken into account as well. The initial part of the project is a pre-study with focus on ergonomics and human factors. This pre-study included a study in relevant literature, contact with a manufacturing company and an analysis of the possible competitor’s lifting tools. The results from the pre-study have further been used to define the specification of requirements, which is the foundation for the concept development. The concept development has undergone a number of different phases. All of the lifting tool’s main functions were broken down and developed individually. The functions were as follows; adjustment of the suction cups, lifting from different heights and handling. The most suitable solution for each main function were chosen and assembled into one final concept. The final concept has been analysed and further developed in order to please the employer and the users of the lifting tool. Some details in the design have been changed in order to ease the manufacturing of the lifting tool. To ensure that the final concept matches the specification of requirements, strength calculations and FEM analysis have been made and anthropometrical measurements have been taken into account. The final chapters include a discussion and recommendations for further development of the lifting tool.
344

Schoolbag carriage : design, adjustment, carriage duration and weight : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Ergonomics at Massey University, Palmerston North, New Zealand

Mackie, Hamish William January 2006 (has links)
There is anecdotal and scientific evidence to suggest that schoolbag carriage is associated with musculoskeletal discomfort (MSD) and possibly long-term back pain. Thus schoolbag carriage is an area of concern for students, parents and both education and health professionals. A schoolbag weight limit of 10% of body weight (BW) is currently recommended. However, it is based on subjective observations rather than objective findings and does not consider other aspects of schoolbag carriage such as schoolbag design and adjustment or carriage patterns. Five studies were conducted in order to determine the effects on students' responses to schoolbag carriage of schoolbag design, adjustment, carriage duration and weight. Backpack design had a significant effect on reported musculoskeletal discomfort and choice of backpack. Schoolbag hip-belt and shoulder strap adjustment and weight significantly affected shoulder strap tension forces and shoulder interface pressure in simulated schoolbag carriage. Using activity monitoring, school students were found to spend approximately two hours carrying their schoolbags each day. This usually comprised 11-15 times per day of 8-9 minutes of carriage. Using this temporal pattern information, 16 boys (13-14 years) were exposed to a simulated school day using schoolbags weighing 0, 5, 10, 12.5 and 15% BW and an additional condition of 10% BW with tighter shoulder straps. Posture, rating of perceived exertion (RPE), muscular strain and reported ability to walk and balance were significantly affected when schoolbag load reached 10% BW. However, despite these findings, the magnitude of self reported muscular strain and MSD suggested that 15% BW may be too heavy for school students. Thus, 10% BW may be an appropriate upper schoolbag weight limit for a typical school day. Using a psychophysical approach the mean (standard deviation) maximum acceptable schoolbag weight (MASW) selected by 16 school boys (13-14 years) was 10.4(3.8) %BW. This finding agrees with the findings of the previous study and supports the current schoolbag weight recommendation of 10% BW. The results of the five studies can be used in developing schoolbag carrying guidelines to help reduce the prevalence of MSD amongst school students.
345

Work technique in lifting and patient transfer tasks /

Kjellberg, Katarina, January 2003 (has links) (PDF)
Diss. (sammanfattning) Göteborg : Univ., 2003. / Härtill 5 uppsatser.
346

The patient transfer task : methods for assessing work technique /

Johnsson, Christina, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.
347

Investigation of an aeroelastic model for a generic wing structure

Cilliers, M. E. 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Computational Aeroelasticity is a complex research field which combines structural and aerodynamic analyses to describe a vehicle in flight. This thesis investigates the feasibility of including such an analysis in the development of control systems for unmanned aerial vehicles within the Electronic Systems Laboratory at the Department of Electrical and Electronic Engineering at Stellenbosch University. This is done through the development of a structural analysis algorithm using the Finite Element Method, an aerodynamic algorithm for Prandtl’s Lifting Line Theory and experimental work. The experimental work was conducted at the Low-Speed Wind Tunnel at the Department of Mechanical and Mechatronic Engineering. The structural algorithm was applied to 20-noded hexahedral elements in a winglike structure. The wing was modelled as a cantilever beam, with a fixed and a free end. Natural frequencies and deflections were verified with the experimental model and commercial software. The aerodynamic algorithm was applied to a Clark-Y airfoil with a chord of 0:1m and a half-span of 0:5m. This profile was also used on the experimental model. Experimental data was captured using single axis accelerometers. All postprocessing of data is also discussed in this thesis. Results show good correlation between the structural algorithm and experimental data. / AFRIKAANSE OPSOMMING: Numeriese Aeroelastisiteit is ’n komplekse navorsingsveld waar ’n vlieënde voertuig deur ’n strukturele en ’n aerodinamiese analise beskryf word. Hierdie tesis ondersoek die toepaslikheid van hierdie tipe analise in die ontwerp van beheerstelsels vir onbemande voertuie binne die ESL groep van die Departement Elektriese en Elektroniese Ingenieurswese by Stellenbosch Universiteit. Die ondersoek bevat die ontwikkeling van ’n strukturele algoritme met die gebruik van die Eindige Element Methode, ’n aerodinamiese algoritme vir Prandtl se Heflynteorie en eksperimentele werk. Die eksperimentele werk is by die Department Meganiese en Megatroniese Ingensierswese toegepas in die Lae-Spoed Windtonnel. Die strukturele algoritme maak gebruik van ’n 20-nodus heksahedrale element om ’n vlerk-tipe struktuur op te bou. Die vlerk is vereenvouding na ’n kantelbalk met ’n vasgeklemde en ’n vrye ent. Natuurlike frekwensies en defleksies is met die eksperimentele werk en kommersiële sagteware geverifieer. Die aerodinamiese algoritme is op ’n Clark-Y profiel met 0:1m koord lengte en ’n halwe vlerk length van 0:5m geïmplementeer. Die profiel is ook in die eksperimentele model gebruik. Die eksperimentele data is met eendimensionele versnellingsmeters opgeneem. Al die verdere berekeninge wat op ekperimentele data gedoen is, word in die tesis beskryf. Resultate toon goeie korrelasie tussen die strukturele algoritme en die eksperimentele data.
348

Miljöprestanda för lastbilskran : En studieav olika nyttjandescenarier

Lundblad, Nora January 2017 (has links)
Denna kandidatuppsats är en studie av miljöprestandan hos   en lastbilskran satt i relation till användning av en mobilkran.   Miljöprestandan hos lastbilskranen studeras och jämförs med mobilkranens   givet ett visst nyttjandescenario. Miljöprestandan mäts i miljöparametrarna:   klimatpåverkan, energiförbrukning, energieffektivitet samt partikelutsläpp.   Realistiska och mätbara nyttjandescenarier har utarbetats utifrån studiebesök   och intervjuer med Vemservice, Jämtlands Mobilkranar och Curt Sillström   Åkeri. Kandidatuppsatsen är skriven som en del i den miljöstudie som ingår i   utvecklingsprojektet Forskning och utveckling av lastbilars   centralram för minskad miljöpåverkan vid tung transport. Projektet   drivs av Vemservice (Vemdalsservice AB) och syftar till att utveckla   centralramen på en lastbilskran genom att öka dess lyftkapacitet. Projektets   mål är att ersätta mobilkranar med lastbilskranar i en högre utsträckning än   vad som görs idag. I projektet deltar även teknikkonsultföretaget DRIV   Innovation, materialoptimeringstjänsten SSAB Shape samt Mittuniversitetet. En lastbilskran är en lastbil med en kran påmonterad på   flaket, med plats på flaket för att transportera gods. Lyftförmågan hos en   lastbilskran beror både av kranens styrka och själva lastbilens vrid- och böjhållfasthet.   I denna studie har en lastbilskran från Curt Sillströms Åkeri studerats.   Lastbilskranens främsta användningsområden är vid nybyggnationer av   bostäder, flytt av containrar och bodar på arbetsplatser samt vid flytt av   tunga föremål in och ut ur byggnader. Mobilkran kallas det   arbetsfordon som har en lyftkran med svängarm monterad på fordonet, den används inte för transport av gods.   Mobilkranen i denna studie tillhör Jämtlands Mobilkranar och används främst i   lyftarbeten såsom byggande av bostäder och arbeten vid vattenkraftverk. Resultatet   av den studerade miljöprestandan baseras på tre specifika nyttjandescenarior.   Nyttjandescenarierna innefattade att transportera och lyfta en given mängd   gods en given sträcka och tid. Lastbilskranen har högre miljöprestanda än   mobilkranen vid jämförelse i de tre scenarierna, dvs. lägre utsläpp och   mindre energiförbrukning. Den minsta skillnaden i miljöprestanda uppstår när   enbart lyftarbete utförs, då lastbilskranens fulla funktion inte nyttjas då   den ej transporterar något gods. Det troligtvis mest typiska   nyttjandescenariot är att gods både ska transporteras och lyftas. I detta   fall har lastbilskranen flera fördelar tack vare att dess fulla funktion   utnyttjas. / This bachelor thesis is a study of the environmental performance of a loader crane in relationship to the usage of a mobile crane. The environmental performance of the loader crane is studied and compared to the mobile cranes performance given a set of specific user scenarios. The environmental performance is measured using the following environmental parameters:climate impact, energy consumption, energy efficiency and particle emissions. Realistic and measurable user scenarios were prepared using information from visits and interviews with Vemservice, Jämtlands Mobilkranar and Curt Sillström Åkeri. The thesis is written as a part of the environmental study that is included in the developmental project “Forskning och utveckling av lastbilars centralram för minskad miljöpåverkan vid tung transport”. The project is managed by Vemservice (Vemdalsservice AB) and the purpose of the project is to develop the frame on a loader crane by increasing the capacity for lifting. The goal of the project is to replace mobile cranes with loader cranes to a higher degree than what is currently the case. The projects participants are also made up by the technology consulting DRIV Innovation, SSAB Shape and also Mid Sweden University. A loader crane is a truck with a crane mounted on its flatbed and also room on the flatbed for the transport of goods. The lifting capabilities of a loader crane is dependent on the strength of the crane and the rigidity of the frame of the truck itself. In this thesis, a loader crane from Curt Sillström Åkeri AB is studied. The main usage of the loader crane in this study is in construction, the moving of work site sheds and in the moving of heavy objects in and out of houses. A mobile crane is a work vehicle with a crane and swing arm mounted on the back of the vehicle. The mobile crane in this study belongs to Jämtlands Mobilkranar and is primary used for heavy lifting in construction and work at a hydro power plant. As opposed to the loader crane, the mobile crane is not used for the transport of goods. The resulting environmental performance was based on three specific user scenarios. The user scenarios consisted of lifting and transporting a given amount of goods for a specified distance and time. When a comparison is made between the loader crane and mobile crane for total emissions and energy consumption in each user scenario, the loader crane has a larger environmental performance. The smallest difference in environmental performance arises when lifting is the only work being done, due to the fact that the full capacity of the loader crane is not utilized since it is not used to transport goods. Likely the most typical user scenario consists of goods being both transported and lifted. In this case the loader crane has a number of advantages because its full capacity is being utilized. / <p>2018-02-01</p>
349

Movimentação manual de pacientes e o profissional de saúde um estudo transversal /

Bernardes, João Marcos January 2018 (has links)
Orientador: Adriano Dias / Resumo: O objetivo desta pesquisa foi investigar a associação entre movimentação manual de pacientes e (1) a prevalência de distúrbios osteomusculares na região lombar e (2) a capacidade para o trabalho em profissionais da saúde, além de, (3) avaliar o grau de conhecimento desses profissionais sobre a movimentação manual de pacientes. Trata-se de um estudo transversal, cuja amostra foi composta por 320 profissionais de saúde que atuavam profissionalmente no Hospital das Clínicas da Faculdade de Medicina de Botucatu. Os resultados desta pesquisa foram três artigos científicos, apresentados neste manuscrito. O primeiro teve por objetivo investigar a prevalência de dor lombar e a associação desta com a movimentação manual de pacientes. A prevalência de período (três meses) de dor lombar foi de 57,8% (IC 95% 52,3%- 63,2%). A presença de dor lombar esteve significativamente associada com a movimentação manual de pacientes; de acordo com o modelo múltiplo de Poisson com variância robusta, a prevalência de dor lombar foi 44,4% maior (RP 1,444, IC 95% 1,169-1,783) entre os indivíduos que realizavam este tipo de atividade. O objetivo do segundo artigo foi avaliar a capacidade para o trabalho dos participantes e sua associação com a movimentação manual de pacientes. A pontuação média do Índice de Capacidade para o trabalho foi de 38,03 pontos (DP 6,15, IC 95% 37,33-38,72). A capacidade de trabalho inadequada (pontuação inferior a 37 pontos no Índice de Capacidade para o Trabalho) esteve signif... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this research was to investigate the association between manual patient handling and (1) low back pain prevalence and (2) work ability among healthcare workers, and, also, (3) to examine their knowledge level of safe patient handling. This is a cross-sectional study. The sample consisted of 320 healthcare workers who worked at the University Hospital of Botucatu Medical School. The results of this research were three scientific papers, presented in this manuscript. The first one investigated low back pain prevalence and its association with manual patient handling. The 3-month period prevalence of low back pain was 57.8% (95% CI 52.3%- 63.2%). Low back pain was significantly associated with manual patient handling; according to the multiple Poisson regression model with robust variance low back pain prevalence was 44.4% higher (PR 1.444, 95% CI 1.169-1.783) among individuals who performed this activity. The second one evaluated the level of work ability and its association with manual patient handling. The Work Ability Index mean score was 38.03 points (SD 6.15, 95% CI 37.33-38.72). An inadequate level of work ability (Work Ability Index score lower than 37 points) was significantly associated with manual patient handling; according to the multiple Poisson regression model with robust variance inadequate level of work ability was 37.5% higher (PR 1.375, 95% CI 1.038-1.821) among individuals who performed this activity. Finally, the third one examined the knowle... (Complete abstract click electronic access below) / Doutor
350

Geração de Facetas para Politopos de Conjuntos Independentes / Facet-generating Procedures for Stable Set Polytopes

Xavier, Alinson Santos January 2011 (has links)
XAVIER, Alinson Santos. Geração de Facetas para Politopos de Conjuntos Independentes. 2011. 141 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Computação, Fortaleza-CE, 2011. / Submitted by guaracy araujo (guaraa3355@gmail.com) on 2016-05-23T19:04:42Z No. of bitstreams: 1 2011_dis_asxavier.pdf: 1098827 bytes, checksum: b69a55ab904901d692a7afbf26cfbb04 (MD5) / Approved for entry into archive by guaracy araujo (guaraa3355@gmail.com) on 2016-05-23T19:10:07Z (GMT) No. of bitstreams: 1 2011_dis_asxavier.pdf: 1098827 bytes, checksum: b69a55ab904901d692a7afbf26cfbb04 (MD5) / Made available in DSpace on 2016-05-23T19:10:07Z (GMT). No. of bitstreams: 1 2011_dis_asxavier.pdf: 1098827 bytes, checksum: b69a55ab904901d692a7afbf26cfbb04 (MD5) Previous issue date: 2011 / A stable set of a graph is a set of pairwise non-adjacent vertices. The maximum stable set problem is to find a stable set of maximum cardinality in a given graph. The maximum induced k-partite subgraph problem is to find k stable sets such that their union has maximum cardinality. Besides having applications in various fields, including computer vision, molecular biology and VLSI circuit design, these problems also model other important combinatorial problems, such as set packing and vertex coloring. In the present work, we study the facial structure of the polytopes associated with both problems. First, we describe a new facet generating procedure for the stable set polytope, which unifies and subsumes several previous procedures. Besides generating many well-known facet inducing inequalities, this procedure can also generate new facet-inducing inequalities which have not been previously described. Then, we study the maximum induced k-partite polytope formulated by asymmetric representatives. We describe its simplest facets, show that some of its facets arise from vertex induced subgraphs, and identify two classes of subgraphs which generate facets of the polytope. To reach these main results, we study the affine equivalence between polyhedra, and also develop a new facet generating procedure for general polyhedra which subsumes the many versions of the lifting of variables. / Um conjunto independente de um grafo é um subconjunto de vértices que não contém nenhum par de vértices vizinhos. O problema do maior conjunto independente consiste em encontrar um conjunto independente de cardinalidade máxima. O problema do maior subgrafo induzido k-partido consiste em encontrar k conjuntos independentes cuja união tenha cardinalidade máxima. Além de possuírem aplicação em diversas áreas, como visão computacional, biologia molecular e projeto de circuitos integrados, estes problemas também modelam outros problemas de otimização combinatória, como empacotamento de conjuntos e coloração de vértices. Neste trabalho, estudamos os politopos associados aos dois problemas. Primeiro, descrevemos um novo procedimento de geração de facetas para o politopo de conjuntos independentes, que unifica e generaliza diversos procedimentos anteriores. Além de gerar várias classes de desigualdades indutoras de facetas já conhecidas, este procedimento também gera novas desigualdades que ainda não foram descritas na literatura. Em seguida, estudamos o politopo do subgrafo induzido k-partido associado à formulação por representantes de cor. Identificamos suas facetas mais simples, mostramos que facetas podem ser geradas a partir de subgrafos induzidos, e descrevemos duas classes de subgrafos que geram facetas deste politopo. Para obter os principais resultados desta dissertação, fazemos um estudo da relação de afim-isomorfismo entre poliedros, e desenvolvemos um novo procedimento de conversão de faces em facetas que generaliza as diversas versões do procedimento de levantamento de variáveis.

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