Probabilistic graphical models (PGMs) provide the capability of evaluating uncertainty and variability of product use in addition to correlating the results with aspects of the usage context. Although energy consumption during use can cause a majority of a product's environmental impact, common practice is to neglect operational variability in life cycle inventories (LCIs). Therefore, the relationship between a product's usage context and its environmental performance is rarely considered in design evaluations. This dissertation demonstrates a method for describing the usage context as a set of factors and representing the usage context through a PGM. The application to LCIs is demonstrated through the use of a lightweight vehicle design example. Although replacing steel vehicle parts with aluminum parts reduces the weight and can increase fuel economy, the energy invested in production of aluminum parts is much larger than that of steel parts. The tradeoff between energy investment and fuel savings is highly dependent upon the vehicle fuel economy and lifetime mileage. The demonstration PGM is constructed from relating factors such as driver behavior, alternative driving schedules, and residential density with local conditional probability distributions derived from publicly available data sources. Unique scenarios are then assembled from sets of conditions on these factors to provide insight for sources of variance. The vehicle example demonstrated that implementation of realistic usage scenarios via a PGM can provide a much higher fidelity investigation of energy savings during use and that distinct scenarios can have significantly different implications for the effectiveness of lightweight vehicle designs. Scenarios with large families, for example, yield high energy savings, especially if the vehicle is used for commuting or stop-and-go traffic conditions. Scenarios of small families and efficient driving schedules yield lower energy savings for lightweight vehicle designs. / text

The first line of defence against wireless attacks in Radio Frequency Identi cation (RFID) systems is authentication of tags and readers. RFID tags are very constrained in terms of power, memory and size of circuit. Therefore, RFID tags are not capable of performing sophisticated cryptographic operations. In this dissertation, we have designed light-weight authentication schemes to securely identify the RFID tags to readers and vice versa. The authentication schemes require simple binary operations and can be readily implemented in resource-constrained Radio Frequency Identi cation (RFID) tags. We provide a formal proof of security based on the di culty of solving the Syndrome Decoding (SD) problem. Authentication veri es the unique identity of an RFID tag making it possible to track a tag across multiple readers. We further protect the identity of RFID tags by a light-weight privacy protecting identifi cation scheme based on the di culty of the Learning Parity with Noise (LPN) complexity assumption. To protect RFID tags authentication against the relay attacks, we have designed a resistance scheme in the analog realm that does not have the practicality issues of existing solutions. Our scheme is based on the chaos-suppression theory and it is robust to inconsistencies, such as noise and parameters mismatch. Furthermore, our solutions are based on asymmetric-key algorithms that better facilitate the distribution of cryptographic keys in large systems. We have provided a secure broadcast encryption protocol to effi ciently distribute cryptographic keys throughout the system with minimal communication overheads. The security of the proposed protocol is formally proven in the adaptive adversary model, which simulates the attacker in the real world.

This paper presents a metallic structural solution for communities with minor resources, which is able to adapt to the climatic conditions of La Guajira (Colombia). The mains objectives of this structure are to reach good quality and reduce execution time as well as cost. The structure was designed by using Light Weight Steel Framing method, due to its simplicity as well as its ease in the assembly due to the lack of resources in those communities. The design was calculated by using an iterative method in which a compromise solution between prices and strength was reached. This paper concludes that the same structure which was being built, can be improved (decreasing of the price, and industrialisation of the method) by using the structural solution proposed by this work.

abstract: This study employs a finite element method based modeling of cementitious composite microstructure to study the effect of presence of inclusions on the stress distribution and the constitutive response of the composite. A randomized periodic microstructure combined with periodic boundary conditions forms the base of the finite element models. Inclusion properties of quartz and light weight aggregates of size 600μm obtained from literature were made use of to study the effect of their material (including inclusion stiffness, stiffness of interfacial transition zone and matrix stiffening) and geometric properties (volume fraction of inclusion, particle size distribution of inclusion and thickness of the interfacial transition zone) on the composite. Traction-separation relationship was used to incorporate the effect of debonding at the interface of the matrix and the inclusion to study the effect on stress distribution in the microstructure. The stress distributions observed upon conducting a finite element analysis are caused due to the stiffness mismatch in both the quartz and the light weight aggregates as expected. The constitutive response of the composite microstructure is found to be in good conformance with semi-analytical models as well as experimental values. The effect of debonding throws up certain important observations on the stress distributions in the microstructure based on the stress concentrations and relaxations caused by the stiffness of the individual components of the microstructure. The study presented discusses the different micromechanical models employed, their applicability and suitability to correctly predict the composite constitutive response. / Dissertation/Thesis / Masters Thesis Civil Engineering 2016

A tecnologia construtiva em chapas delgadas estruturadas em Light Steel Framing (LSF) vem sendo introduzida no mercado nacional como uma alternativa para substituir a tecnologia tradicional com vedações externas em alvenaria e revestimentos aderidos, comumente utilizada para execução de fachadas em edifícios de múltiplos pavimentos. Trata-se de uma tecnologia com montagem a seco que traz potenciais benefícios em relação ao método tradicional de produção de fachadas, notadamente em relação a: otimização da logística no canteiro de obra; simplificação dos procedimentos de acompanhamento e controle das etapas executivas; alta produtividade, com potencial redução dos prazos de obra; fácil controle sobre o custo final do serviço; e redução de riscos quanto ao cumprimento dos prazos planejados para o desenvolvimento e conclusão da atividade. O objetivo do presente trabalho é comparar os diferenciais no planejamento da obra e no custo de produção entre essa tecnologia e o método tradicional para execução de fachadas de edifícios de múltiplos pavimentos, considerando-se um mesmo projeto arquitetônico. Como método para o desenvolvimento do trabalho, adotou-se: pesquisa bibliográfica; entrevistas com profissionais, fabricantes e empresas especializadas na montagem da tecnologia em chapas delgadas estruturadas em Light Steel Framing (LSF); pesquisa quanto às alternativas disponíveis para o LSF e quanto aos custos praticados no mercado nacional para ambas as tecnologias; e acompanhamento de obras em LSF visando aprofundar os conhecimentos sobre seu método de execução de fachada. Pela escassa literatura nacional sobre o tema e pelo ainda incipiente conhecimento sobre esta tecnologia no meio técnico e acadêmico, acredita-se que o presente trabalho apresenta informações relevantes para profissionais ou empresas dispostas a inovar na execução desse importante subsistema das edificações, adotando a tecnologia com painéis leves em seus futuros projetos. / The building technology of light weight external sheets structured in Light Steel Framing (LSF) has been introduced in the domestic market as an alternative to replace traditional exterior masonry and mortar cladding technology commonly used for façade construction in multiple floors buildings. It is a technology with dry assembly that brings potential benefits in relation to the traditional method of façade production, especially in relation to: optimization of the logistics in the construction site; simplification of procedures for monitoring and controlling the executive stages; high productivity, with potential reduction of work deadlines; easier control over the final cost of the service; and reduction of risks regarding compliance with the deadlines planned for the development and completion of the activity. The objective of the present work is to compare the differentials in the planning of the work and the cost of production between this technology and the traditional method for the execution of façades of multiple floors buildings, considering the same architectural design. As a method for the development of the work, it was adopted: bibliographic research; interviews with professionals, manufacturers and companies specializing in the assembly of thin sheet structured in Light Steel Framing (LSF) technology; research on the alternatives available to the light weight external sheets structured in LSF technology and on the costs practiced in the national market for both technologies; follow-up of works in LSF aiming to deepen the knowledge about its method of execution of facade. Due to the scarce national literature on the subject and the still incipient knowledge about this technology in the technical and academic environment, it is believed that the present work presents relevant information for professionals or companies willing to innovate in the execution of this important subsystem of the buildings, adopting the technology with light weight panels for façade production in their future projects.

The first line of defence against wireless attacks in Radio Frequency Identi cation (RFID) systems is authentication of tags and readers. RFID tags are very constrained in terms of power, memory and size of circuit. Therefore, RFID tags are not capable of performing sophisticated cryptographic operations. In this dissertation, we have designed light-weight authentication schemes to securely identify the RFID tags to readers and vice versa. The authentication schemes require simple binary operations and can be readily implemented in resource-constrained Radio Frequency Identi cation (RFID) tags. We provide a formal proof of security based on the di culty of solving the Syndrome Decoding (SD) problem. Authentication veri es the unique identity of an RFID tag making it possible to track a tag across multiple readers. We further protect the identity of RFID tags by a light-weight privacy protecting identifi cation scheme based on the di culty of the Learning Parity with Noise (LPN) complexity assumption. To protect RFID tags authentication against the relay attacks, we have designed a resistance scheme in the analog realm that does not have the practicality issues of existing solutions. Our scheme is based on the chaos-suppression theory and it is robust to inconsistencies, such as noise and parameters mismatch. Furthermore, our solutions are based on asymmetric-key algorithms that better facilitate the distribution of cryptographic keys in large systems. We have provided a secure broadcast encryption protocol to effi ciently distribute cryptographic keys throughout the system with minimal communication overheads. The security of the proposed protocol is formally proven in the adaptive adversary model, which simulates the attacker in the real world.

The purpose of this research is to investigate the structural efficiency of 8-node IsoTruss structures subject to uniaxial compression using numerical, dimensional, and optimization methods. The structures analyzed herein are based on graphite/epoxy specimens that were designed for light-weight space applications, and are approximately 10 ft. (3 m) long and 0.3 lb. (0.14 kg). The principal failure modes considered are material failure, global buckling, local buckling at the bay level, and longitudinal strut buckling. Studies were performed with the following objectives: to correlate finite element predictions with experimental and analytical methods; to derive analytical expressions to predict bay-level buckling; to characterize interrelations between design parameters and buckling behavior; to develop efficient optimization methods; and, to compare the structural efficiency of outer longitudinal configurations with inner longitudinal configurations. Finite element models were developed in ANSYS, validated with experimental data, and verified with traditional mechanics. Data produced from the finite element models were used to identify trends between non-dimensional Pi variables, derived with Buckingham's Pi Theorem. Analytical expressions were derived to predict bay-level buckling loads, and verified with dimensional analyses. Numerical and dimensional analyses were performed on IsoTruss structures with outer longitudinal members to compare the structural performance with inner longitudinal configurations. Analytical expressions were implemented in optimization studies to determine efficient and robust optimization techniques and optimize the inner and outer longitudinal configurations with respect to mass. Results indicate that the finite element predictions of axial stiffness and global buckling loads correlate with traditional mechanics equations, but overestimate the capacity demonstrated in previously published experimental results. The buckling modes predicted by finite element predictions correlate with traditional mechanics and experimental results, except when the local and global buckling loads coincide. The analytical expressions derived from mechanics to predict local buckling underestimate the constraining influence of the helical members, and therefore underestimate the local buckling capacity. The optimization analysis indicates that, in the specified design space, the structure with outer longitudinal members demonstrates a greater strength-to-weight ratio than the corresponding structure with inner longitudinal members by sustaining the same loading criteria with 10% less mass.

Master thesis contains project documentation of low-energy multifunctional house with a full basement, three floors and finished with a flat roof. It is a detached house situated in a residential building area in capital city of Slovakia - Bratislava, district Podunajské Biskupice. The basement walls and columns are made of reinforced concrete. The basement is used as a garage with twenty-two parking spaces for flats owners and there is also placed a workshop room. Above-ground floors are designed as a reinforced concrete frame filled circumferentially with light-weight concrete blocks. Exterior cladding is covered by heat insulation. The interior vertical, non-load-bearing walls are made of plasterboard. On the ground floor are two shops and a restaurant with a terrace. There are eleven flats on the other two floors. On the second floor are seven double-bedroom flats with an open plan kitchen lounge area, four of them have a balcony. On the third floor are four flats with a terrace, three of them are two double bedroom flats with an open plan kitchen lounge area, and the fourth one is a one double bedroom flat with open plan kitchen lounge area. The entrance for shops and main entrance for flats are on the north-west side. The entrance for the restaurant is on the north-east side.

Im Rahmen der vorgelegten Arbeit wurde das Niederdruck-Hohlteilgießverfahen untersucht. Dieses Verfahren beruht auf dem Niederdruckgießverfahren, jedoch wird die Druckbeaufschlagung auf das System vor dem kompletten Erstarren des Gussstückes beendet, wodurch nicht erstarrtes Material aus der Form fließen kann und ein hohles Gussstück ohne Einsatz von Kernen entsteht. Im Rahmen dieser Arbeit wurden Probekörper aus verschiedenen Al-Legierungen in Sand- und Metallformen hergestellt und ausgewertet, wobei die Einflussfaktoren Druckhaltezeit und Temperaturgradient zwischen Schmelze und Form variiert wurden. Anschließend erfolgte eine Auswertung der Probekörper hinsichtlich Ausbildung der Wanddicke und deren Rauhigkeit. Dabei wurden Abhängigkeiten zwischen Haltezeit und Wanddicke gefunden. Die Rauhigkeit des ausgebildeten Hohlraumes ist dabei legierungsabhängig und unterscheidet sich zwischen Sand- und Kokillenguss stark.

No description available.