The estimation of the time required to construct building projects has been a topic of great interest to many researchers and practitioners. Delays are a common problem in the construction industry and may be motivated by different factors. In this context, prediction of the construction time of building projects at early project phases has been considered a key element for project success. Initially, the construction time of a building is affected by several factors related to project features, although some factors are more crucial than others. Based on these factors, for the purpose of providing proper tools to estimate construction time and minimise the subjectivity in such estimation, to date, most research works have presented parametric models which were built using linear regression analysis (LRA). Nevertheless, there is an increasing trend for using artificial neural networks (ANNs) to develop better predictive models. In order to produce the best possible predictive models and provide a clearer explanation regarding the relationships that exist between different project scope factors and the construction time of new builds, the research work presented in this thesis used two data sets and three different modelling techniques: LRA, ANNs and a new numerical methodology based on the finite element method (FEM). In particular, this thesis addressed the general assumption that nonlinear modelling techniques are likely to better represent the previously mentioned relationships than LRA. According to available data, predictor variables related to construction costs, gross floor area (GFA), number of floors, and the type of facility were selected to analyse their influence on the duration of the construction process. Additionally, and since that there is no general agreement in the literature regarding which is the most appropriate dependent variable for predicting construction time, both time and speed of construction were analysed to determine which of these offer better predictive models. In this regard, construction speed can be used as a useful and robust benchmark for comparison of contractor performance. In the case of ANNs, two different types of network architectures were tested: the multilayer perceptron (MLP) and the radial basis function (RFB). The modelling process of MLP networks was divided into five stages: (i) selection of the training methodology, (ii) data division, (iii) design of the initial network structure, (iv) network optimisation, and (v) validation of the optimised models. MLP networks were used in conjunction with two different training algorithms and five options for calibration data division. In addition, a methodology was defined to obtain optimised MLP networks with an adequate predictive performance. This methodology develops a stepwise trial and error procedure in which a basic MLP network structure, with enough consistency, is first established and subsequently this initial structure is modified at each step of the proposed optimisation process in order to achieve the best possible network configuration. This thesis also proposes a framework to evaluate the performance of predictive models which includes five different assessment criteria: (i) verification of compliance with the underlying assumptions regarding the statistical procedure used to obtain the models, (ii) checking the goodness of fit of the models to the data set used for generating them, (iii) validation of models in terms of ability to generalise, (iv) assessment of the balance existing between the ability of a model to generalise and the accuracy obtained with the calibration data, and (v) development of a sensitivity analysis to verify model stability. Finally, a sensitivity analysis was also proposed to evaluate the impact of the construction cost variability, caused by the uncertainty in its estimation, on the performance of predictive models. The results obtained with this thesis showed that construction speed is a more appropriate dependent variable than construction time to develop predictive models to estimate the construction process duration of building projects, and that such construction speed is affected more by GFA than by construction cost. Furthermore, the FEM-based numerical methodology provided better predictive models than those generated by MLP networks and LRA. In this regard, the findings of this research work support the idea that linear regression models can provide a good starting point from which to search for better predictive models using nonlinear modelling techniques. The knowledge gained from this thesis will allow for new approaches to be explored in order to better determine the relationships existing between project scope factors and the construction speed of new builds, but always taking into account that the results provided by the models proposed herein are only initial construction speed estimates at early stages of project development, when only basic information is available, and are not intended to replace detailed schedules undertaken by builders.

This thesis deals with a CAD programmed construction design of dental prosthetics and its subsequent production by means of a five axis machine tool. In the theoretical part of the thesis one can find characteristics and analysis of materials designed for a production of dental prosthetics constructions. Among other things, the practical part of the thesis follows up digitization of a patient´s oral cavity part with the use of Trios intraoral scanner representing the latest scanning technology. The obtained data created a basis for a design of the respective dental prosthetics construction using the shape dental system programme called DentalDesigner 2015. Furthermore, the paper deals with a production of a dental prosthetics construction by means of a five axis machine tool and pursues completion works which resulted in the prosthetics final shape. The paper is concluded with discussion comprising a summary of results acquired in the practical part beginning from dental implant introduction to insertion of the made prosthetics construction into the patient´s oral cavity.

Att bygga bjälklag av massivt trä blir allt vanligare och är ett sätt att minska klimatavtrycket från byggbranschen. Korslimmat trä, även kallat KL-trä, står för lejonparten av dessa massiva träbjälklag. Ett mindre vanligt alternativ till KL-trä är brädstapelbjälklag. Fördelen med brädstapelbjälklag är att fiberriktningen på virket går i samma riktning. Detta ger en något högre styvhet så man kan bygga lägre moduler med mindre virke och således spara på trä och dessutom slippa användningen av lim. Om man därutöver kan sätta ihop modulerna på plats slipper man tunga transporter och industriell tillverkning. En nackdel med brädstapelbjälklag är att man historiskt har använt spikar av metall som både går emot principen att bygga med enbart trä och dessutom försvårar möjligheter till återbruk av trämaterialet. LignoLoc är en spik tillverkad av densifierat bokträ och en relativt ny produkt på marknaden. Spiken skjuts in i virket med tryckluft och friktionen får ligninet i spiken att delvis smälta ihop med det omgivande virket. Svetseffekten tillsammans med det densifierade trämaterialet ger relativt goda hållfasthetsvärden, speciellt vid dragbelastning. I detta examensarbete undersöks hur man kan bygga brädstapelbjälklag med LignoLoc spik som uppfyller gällande brukskrav för nedböjning och vibration samt för brand. Undersökningen utgår ifrån befintlig teori för konstruktion av brädstapelbjälklag med trådspik och kombineras med studier kring LignoLoc spikens uppmätta egenskaper och tillämpade beräkningsmodeller. Med detta som grund görs en ansats till en generell beräkningsmodell för konstruktion av brädstapelbjälklag med LignoLoc spik. För att befästa ansatsen utförs även en praktisk hållfasthetsstudie i en storskalig modell där tre olika moduler belastningstestas i en hydraulisk press. Slutsatsen är att de tillämpade beräkningsmodellerna stämmer väl överens med utfallen från de praktiska belastningstesterna. Testerna tyder på att LignoLoc spiken håller långt över förväntan för skjuvbrott och ger en marginellt styvare konstruktion än motsvarande med trådspik. Vidare kan konstateras att LignoLoc spiken fungerar gott som alternativ till trådspik. Således kan man bygga brädstapelbjälklag i 100% trämaterial som ett alternativ till KL-trä. / Building floors from solid wood is becoming increasingly common and is a way to reduce the environmental footprint of the construction industry. Cross-laminated timber, also known as CLT, accounts for the majority of these solid wood floors. A less common alternative to CLT is Nail Laminated Timber (NLT). The advantage of NLT is that the grain direction of the timber runs in the same direction. This gives slightly higher stiffness, allowing for the construction of thinner modules with less timber, thus saving on wood and eliminating the need for glue. Additionally, if the modules can be assembled on-site, heavy transportation and industrial manufacturing can be avoided. However, the downside of NLT is that historically, metal nails have been used, which contradicts the principle of building with solid wood and also complicates the reuse of the timber material. LignoLoc is a nail made of densified beech wood and is a relatively new product on the market. The nail is driven into the wood with compressed air, and the friction causes the lignin in the nail to partially melt and fuse with the surrounding wood. This welding effect, combined with the densified wood material, provides relatively good strength values, especially under tensile load. This thesis investigates how to build NLT with LignoLoc nails that meet current serviceability requirements for deflection, fire, and vibration effects. Starting from existing theory for the construction of NLT with metal nails and combining it with studies on the measured properties of LignoLoc nails and applied calculation models, an approach is made to a general calculation model for the construction of NLT with LignoLoc nails. To validate the approach, a practical strength study is also carried out on a large-scale model where three different modules are load-tested in a hydraulic press. The conclusion is that the applied calculation models match well with the outcomes of the practical load tests. The tests indicate that the LignoLoc nail far exceeds expectations for shear failure and provides a marginally stiffer construction than the equivalent with steel nails. Furthermore, it can be stated that the LignoLoc nail works well as an alternative to steel nails. Thus, it is possible to build NLT in 100% wood material as an alternative to CLT.

Submitted by Leonardo Cavalcante (leo.ocavalcante@gmail.com) on 2018-04-23T20:47:31Z No. of bitstreams: 1 Arquivototal.pdf: 1433584 bytes, checksum: fb8978802ac3b768c50f569bc4124e5e (MD5) / Made available in DSpace on 2018-04-23T20:47:31Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 1433584 bytes, checksum: fb8978802ac3b768c50f569bc4124e5e (MD5) Previous issue date: 2014-03-20 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / In this dissertation we develop a rst contact with the theory of Banach Algebras and C*-algebras. As usual of a rst contact, we build the Spectral Theory in Banach algebras with unit. We present the characterization theorems of C *-algebras of Gelfand-Naimark and Gelfand-Naimark-Segal, including the GNS construction. Moreover, we prove a theorem which characterizes all complex homomorphisms in the C*-algebra C(X), as point-evaluation homomorphisms. We also present, as a curiosity, a proof of the Fundamental Theorem of Algebra using the Gelfand-Mazur Theorem. As a prerequisite to the Gelfand-Naimark-Segal's characterization of C *-algebras, we further develop, in the background, the theory of the direct sum of any family of Hilbert spaces. . / Nesta dissertação desenvolveremos um primeiro contato com a Teoria de Álgebras de Banach e C*-álgebras. Como tópico de um primeiro contato, construiremos a Teoria Espectral em Álgebras de Banach com unidade. Apresentaremos os Teoremas de Caracterização de C*-álgebras de Gelfand-Naimark, e Gelfand-Naimark-Segal, incluindo a constru c~ao GNS. Al em disso, provamos um teorema que caracteriza todos os homomor smos complexos na C*-álgebra C(X) como sendo homomor smos de avaliação. Apresentaremos também, como curiosidade, uma prova do Teorema Fundamental da Álgebra a partir do Teorema de Gelfand-Mazur. Como um pré requisito a Caracterização de Gelfand-Naimark-Segal de C*-álgebras, desenvolvemos ainda, em segundo plano, a teoria da soma direta de uma familia qualquer de espaços de Hilbert.