Ce travail de recherche vise à contribuer au développement de nouveaux outils d'estimation d'erreur globale et locale en ingénierie mécanique. Les estimateurs d'erreur globale étudiés reposent sur le concept d'erreur en relation de comportement à travers des techniques spécifiques de construction de champs admissibles, assurant l'aspect conservatif ou garanti de l'estimation. Une nouvelle méthode de construction de champs admissibles est mise en place et comparée à deux autres méthodes concurrentes, en matière de précision, coût de calcul et facilité d'implémentation dans les codes éléments finis. Une amélioration de cette nouvelle méthode hybride fondée sur une minimisation locale de l'énergie complémentaire est également proposée. Celle-ci conduit à l'introduction et à l'élaboration de critères géométriques et énergétiques judicieux, permettant un choix approprié des régions à sélectionner pour améliorer localement la qualité des champs admissibles. Dans le cadre des estimateurs d'erreur locale basés sur l'utilisation conjointe des outils d'extraction et des estimateurs d'erreur globale, deux nouvelles techniques d'encadrement de l'erreur en quantité d'intérêt sont proposées. Celles-ci sont basées sur le principe de Saint-Venant à travers l'emploi de propriétés spécifiques d'homothétie, afin d'améliorer la précision des bornes d'erreur locale obtenues à partir de la technique d'encadrement classique fondée sur l'inégalité de Cauchy-Schwarz. Les diverses études comparatives sont menées dans le cadre des problèmes d'élasticité linéaire en quasi-statique. Le comportement des différents estimateurs d'erreur est illustré et discuté sur des exemples numériques tirés d'applications industrielles. Les travaux réalisés constituent des éléments de réponse à la problématique de la vérification dans un contexte industriel. / This research work aims at contributing to the development of innovative global and goal-oriented error estimation tools applied to Computational Mechanics. The global error estimators considered rely on the concept of constitutive relation error through specific techniques for constructing admissible fields ensuring the recovery of strict and high-quality error estimates. A new hybrid method for constructing admissible stress fields is set up and compared to two other techniques with respect to three different criteria, namely the quality of associated error estimators, the computational cost and the simplicity of practical implementation into finite element codes. An enhanced version of this new technique based on local minimization of the complementary energy is also proposed. Judicious geometric and energetic criteria are introduced to select the relevant zones for optimizing the quality of the admissible fields locally. In the context of goal-oriented error estimation based on the use of both extraction techniques and global error estimators, two new improved bounding techniques are proposed. They lean on Saint-Venant's principle through specific homotheticity properties in order to obtain guaranteed and relevant bounds of better quality than with the classical bounding technique based on the Cauchy-Schwarz inequality. The various comparative studies are conducted on linear elasticity problems under quasi-static loading conditions. The behaviour of the different error estimators is illustrated and discussed through several numerical experiments carried out on industrial cases. The associated results may open up opportunities and help broaden the field of model verification for both academic research and industrial applications.

Adolescent pregnancies are high risks obstetric occurrences. Antenatal care (ANC) provides opportunities to recognise and treat obstetric complications, enhancing the pregnancy outcomes for mothers and babies. This study investigated factors influencing pregnant adolescents' utilisation of ANC services in Bulawayo, using the Health Belief Model's major tenets. A quantitative descriptive design was used in four phases: 80 adolescents' ANC records were audited; structured interviews were conducted with 200 adolescents attending ANC and with 80 adolescents who had delivered their babies without attending ANC; and 52 midwives completed questionnaires portraying their perceptions on adolescents' utilisation of ANC services in Bulawayo. Documentation of ANC services provided to adolescents did not meet the expected standards. Poor or non utilisation of ANC services was influenced by socio demographic factors, individual perceptions of adolescents about antenatal care, perceived benefits of and perceived barriers to the utilisation of ANC. Most pregnant adolescents could not access these services because they could not pay the ANC and/or delivery fees charged at government clinics/hospitals. Midwives required more training in providing and recording adequate ANC services. Free ANC and delivery services could enhance adolescents' pregnancy outcomes in Zimbabawe. An information brochure on the importance of ANC attendance for adolescents has been compiled, based on the research results (see Annexure J). / Health Studies / D.Litt. et Phil. (Health Studies)

Adolescent pregnancies are high risks obstetric occurrences. Antenatal care (ANC) provides opportunities to recognise and treat obstetric complications, enhancing the pregnancy outcomes for mothers and babies. This study investigated factors influencing pregnant adolescents' utilisation of ANC services in Bulawayo, using the Health Belief Model's major tenets. A quantitative descriptive design was used in four phases: 80 adolescents' ANC records were audited; structured interviews were conducted with 200 adolescents attending ANC and with 80 adolescents who had delivered their babies without attending ANC; and 52 midwives completed questionnaires portraying their perceptions on adolescents' utilisation of ANC services in Bulawayo. Documentation of ANC services provided to adolescents did not meet the expected standards. Poor or non utilisation of ANC services was influenced by socio demographic factors, individual perceptions of adolescents about antenatal care, perceived benefits of and perceived barriers to the utilisation of ANC. Most pregnant adolescents could not access these services because they could not pay the ANC and/or delivery fees charged at government clinics/hospitals. Midwives required more training in providing and recording adequate ANC services. Free ANC and delivery services could enhance adolescents' pregnancy outcomes in Zimbabawe. An information brochure on the importance of ANC attendance for adolescents has been compiled, based on the research results (see Annexure J). / Health Studies / D.Litt. et Phil. (Health Studies)

Syftet med denna magisteruppsats har varit att utforska hur Covid-19 pandemin har påverkat ledarskapet och organisationens riktning.    Covid-19 pandemin har påverkar olika delar av ledarskapet. Resultaten visar tydligt att chefer känner sig överbelastade eftersom de måste hantera många administrativa uppgifter och alternerande möten. På grund av brist på tid och balans mellan arbete och privatliv har förmågan att ha en helhetssyn, tolka och ta in perspektiv utifrån och in och inifrån och ut varit en utmaning för ledarna. Resultatet indikerar även på behovet av tydliga kommunikationskanaler mellan ledarna, de anställda och deras kunder om vilka åtgärder som krävs för att anpassa sig till den nya situationen som pandemin har medfört.   Under pandemin har organisationerna tvingats att vidta snabba åtgärder baserat på föreskrifterna och begränsningarna från Folkhälsomyndigheten och regeringen. Etablerade digitala kanaler har använts men nya digitala kanaler har behövts identifieras för att skapa interaktion och relationer inom organisationen samt med kunderna.   Den snabba omvandlingen till den digitala världen har påverkat organisationens riktning att tänka annorlunda, vara mer flexibel och anpassningsbar till nya oväntade förändringar, såsom pandemin. Organisationerna har använt nyckelindikatorer för att identifiera och få en tydlig bild av hur pandemin har påverkat organisationens riktning internt och externt gentemot sina kunder. Denna nya digitala omvandling har också tvingat kunderna att gå in på nya digitala plattformar och interagera online med organisationerna. Den nya digitala medvetenheten från kunderna har framkallat nya digitala krav och tjänster som i sin tur har resulterat i behov av nya digitala självservice tjänster och en högre och starkare digital kompetens från organisationens kundtjänst.   En bidragande diskussion till organisationerna och samhället är att hänvisa till begreppet lönsamhet som en värdeskapande effekt som är hållbar över tid, kopplad till tre element: ledarskap, organisationens riktning och kundbehov. / The purpose of this thesis has been to explore how the Covid-19 pandemic has affected the leadership and the direction of the organization.   The Covid-19 pandemic has affected various parts of the leadership. The results clearly indicate that managers feel overloaded since they have to handle a lot of administrative tasks and alternating meetings. Due to lack of time and balance between work and private life, the ability to have a holistic view, interpret and take in perspectives from outside-in and inside-out has been a challenge for the leaders. The results also indicated the need for clear communication between the leaders and the employees and their customers about what actions are required in order to adapt to the new situation that the pandemic has imposed.   During the pandemic the organizations were forced to take fast action based on the regulations and restrictions from the Public Health Agency and the government. Established digital channels were used but new digital channels had to be identified to create interaction and relations within the organization and with the customers.  The fast transformation to the digital world has affected the direction of the organization to think differently and be more flexible and adaptable to new unexpected changes, such as the pandemic. The organizations have used key indicators to identify and get a clear picture of how the pandemic has affected the direction of the organization internally and externally towards its customers. This new digital transformational shift has also forced the customers to enter new digital platforms and interact online with the organizations. The new digital awareness from the customers has induced new digital requirements and services which in turn have resulted in the need for new digital self-services and a higher and stronger digital competence from the organizations customer service.   A contributing discussion to the organizations and to the society is to refer to the concept of profitability as a value-creating effect sustainable over time, connected by three elements: leadership, direction of the organization and customer need. / <p>2021-06-06</p>