Synergising fingerprint biometrics and cryptography for improved authentication

University of Technology, Sydney. Faculty of Engineering and Information Technology.With the advances in Information Technology (IT) there has been an increase in threats to the communication systems and their assets. One of the most important issues of all Internet Protocol (IP) networks that integrate wireless and wired technologies is the applicability and performance of the electronic identification and authentication methods. These schemes employ a variety of technologies of different degrees of security. Cryptography and biometrics are identified as two of the most important aspects of digital security environments. Biometrics technology nowadays is typically considered a security necessity, tightly coupled with the foundation of highly secure identification and authentication solutions. Also, a biometric system itself is vulnerable to a number of threats. A critical issue in biometric system is to protect the template of a user which is usually stored in a database or a smart card. While cryptography is a powerful tool to accomplish information security, one of the main challenges in crypto systems is to maintain the secrecy of the cryptographic keys. The fuzzy vault construct is a biometric cryptosystem that secures both the secret key and the biometric template by binding them within a cryptographic framework. The ability to work with the fuzzy data which is common in biometric systems makes this method a promising solution for biometric cryptosystems. In many applications, fingerprint has been chosen as a core biometric for the fuzzy vault construction. In this thesis, fingerprint has been selected for further study due to its maturity in terms of availability, uniqueness, permanence, feasibility, ease of use and acceptance. It is expected to address some of the limitations in fingerprint fuzzy vault construction by modifying this structure. Finally, the main contribution of this work is two-fold as follows: 1. An exhaustive review study of the current state of the art in utilising biometrics and cryptography for authentication, more specifically for fingerprint biometric. 2. Proposing a novel method in fingerprints curve extraction which would improve upon current methods on computational load while preserving the required precision. Fingerprints curve extraction is a vital function for both fingerprint classification and extracting the so-called “helper data”. Helper data are required in fuzzy vault implementation

New composite slab system for the structural rehabilitation of traditional buildings

The study presented in this paper is a part of the research project “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, with reference number of PTDC/ECM/113041/2009.In this paper, a new generation of composite sandwich panel slab is proposed as a solution for the rehabilitation of slabs in old masonry buildings. The new slab composite system is composed of four elements that include: High Performance Fiber Reinforced Concrete (HPFRC) layer, GFRP ribs, foam core and GFRP skin. An innovative GFRP-HPFRC hybrid solution has been developed, with a GFRP laminate on the bottom tension skin, and an HPFRC layer on the top compression skin, preventing the occurrence of buckling phenomena, improving the resistance to the effects of impact and fire, providing a ductile behavior and allowing for an easy application of floor covering materials. GFRP ribs and foam core are able to transfer shear stresses between skins. The design process of the proposed hybrid GFRP-HPFRC sandwich panel slab is presented. The effects of various parameters on the behavior of the slabs are investigated by using both linear and material nonlinear analysis, with the aid of the software FEMIX. According to the obtained results, some criteria are established in order to choose the best slab solutions, which include design codes recommendations, failure criteria, serviceability criteria and economic aspects.Fundação para a Ciência e a Tecnologia (FCT

Experimental and numerical investigations on the flexural performance of geopolymers reinforced with short hybrid polymeric fibres

Geopolymers have much higher drying shrinkage than Portland cement based composites Shrinkage performance is an important property for reinforced concrete composites just because a high shrinkage performance is associated to cracking tendency that leads to future durability problems. This paper provides results experimental and numerical investigations of fly ash based geopolymeric mortars reinforced with short hybrid polymeric fibres (SHPF). The results show that SHPF improved the flexural performance, while reducing the compressive strength and flexural stiffness of geopolymeric mortars. The addition of 0.8% SHPF increased about two times the fracture energy and about 50% the tensile strength. The adopted constitutive model well-captured the flexural performance of the tested beams.Foundation for Science and Technologyinfo:eu-repo/semantics/publishedVersio

Development of innovative hybrid sandwich panel slabs: Advanced numerical simulations and parametric studies

The authors honestly appreciate the collaboration of the following institutions: Civitest for developing DHCC materials and PIEP for conducting VARTM process.An innovative hybrid sandwich slab for the rehabilitation of floors in old masonry buildings was conceived, designed, and tested. This structural system is a lightweight composite floor consisting of bottom skin and shear ribs in Glass Fiber Reinforced Polymer (GFRP), a top layer of Deflection Hardening Cement Composites (DHCC), and Polyurethane foam core. In the first part of this study, the material/structural performance of the panel’s concept was assessed by experimental tests. The second part is now dedicated to the execution of advanced numerical simulations, including parametric studies, for assisting on the optimization of this composite slab system and investigating the influence of the relevant characteristics of GFRP and DHCC components. The influence of considering isotropic or orthotropic behavior for the GFRP components and linear or nonlinear behavior for the DHCC are also investigated numerically in terms of accomplishing serviceability and ultimate limit state requisites for this structural system. The parametric studies show that the thickness of GFRP rib is the most important parameter to increase the load carrying capacity of this type of slabs. Based on the results of these parametric studies, two slabs are built and tested experimentally, and the obtained results are not only used to demonstrate the effectiveness of the developed structural system, but also to appraise the predictive performance of the constitutive models adopted in the FEM-based simulations.The study presented in this paper is a part of the research project “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, with reference number of PTDC/ECM/113041/2009. Furthermore, the authors honestly appreciate the collaboration of the following institutions: Civitest for developing DHCC materials and PIEP for conducting VARTM process

Effects of curing conditions on crack bridging response of PVA reinforced cementitious matrix

The effect of the different curing conditions on the response of fiber crack bridging of PVAECC is studied. The self compacting PVA-ECC was cast into the moulds to produce four similar rectangular panels. These panels were kept under different curing conditions for 28 days. The tensile specimens were cut from these panels, and after executing a notch they were tested under tensile loading. The stress versus crack opening relationship for the specimens extracted from panels cured at different conditions is obtained, and the derived results are compared. The dispersion of results, the stress at crack initiation, the maximum fibers bridging stress and the corresponding crack opening, the absorbed energy and the fibers bridging stiffness are the investigated parameters. Also macroscopic images of the fibers in fracture surface are used to interpret the obtained data. As a result of this study a significant influence of different curing conditions on the fiber crack bridging response was observed

Laje sandwich em polímero reforçado com fibra de vidro e argamassa de ultra elevada ductilidade para a reabilitação estrutural

Estudo desenvolvido no âmbito do projeto PTDC/ECM/113041/2009 “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, financiado pela FCT - Fundação para a Ciência e Tecnologia.Neste trabalho apresenta-se um novo sistema estrutural em laje sandwich formada por camada inferior de tração e nervuras transversais em material polimérico reforçado com fibra de vidro (GFRP), núcleo em material leve e com propriedades de isolamento térmico, e camada de compressão em argamassa de ultra elevada ductilidade (UDFRM). Esta última aumenta a resistência à encurvadura local das nervuras transversais de GFRP, contribui para a resistência e ductilidade do comportamento estrutural da laje, aumenta a proteção às temperaturas elevadas e permite a instalação na face superior da laje de elementos cerâmicos ou outros materiais convencionais de acabamento. Dado tratar-se de um tipo de laje com peso próprio muito inferior a qualquer outra solução construtiva existente, a sua aplicação é especialmente vocacionada para a reabilitação estrutural de edifícios de cantaria onde se preservam as paredes resistentes e se pretende remodelar as lajes. Utilizando um programa de cálculo automático baseado no método dos elementos finitos que dispõe de modelos constitutivos apropriados, foi efetuado um estudo paramétrico de forma a otimizar este sistema estrutural.Fundação para a Ciência e a Tecnologia (FCT

Development of innovative hybrid sandwich panel slabs: Experimental results

The authors appreciate the collaboration of the following labs: Civitest for developing DHCC materials, PIEP for conducting VARTM process (Eng. Luis Oliveira) and Department of Civil Engineering of Minho University to perform the tests (Mr. Antonio Matos and Eng. Marco Jorge).In this paper, a new generation of composite sandwich slab is proposed as a solution for the rehabilitation of slabs in old masonry buildings. An innovative solution was developed during this research formed by four components: a Deflection Hardening Cement Composite (DHCC) layer on the top compression skin, a glass fiber reinforced polymer (GFRP) skin at the bottom tension surface, GFRP ribs to transfer shear from top to bottom layers, and foam core for thermal-insolation purposes. The DHCC layer contributes significantly for the load carrying and deflection capacity due to its stiffness, compressive strength and toughness, offers resistance to the occurrence of buckling phenomena in the GFRP ribs, improves the performance of this structural concept against impact and fire, and constitutes an excellent medium for the application of finishing materials, like ceramics or timber. Two different hybrid composite slabs were developed and tested, and their behavior was assessed under flexural loading. The results showed that the developed hybrid sandwich slabs accomplish all design requisites for serviceability and ultimate limit states, and assure a stiffness/dead-weight and load-capacity/dead-weight ratios much higher than conventional structural slab systems.FCT - Fundação para a Ciência e Tecnologi

Investigation of the relationship between organizational justice and employees’ self-management in Arak Municipality

The main aim of this study was to investigate the relationship between organizational justice in three dimensions (i.e. distributive justice, policy justice and intercourse justice) and self-management. These procedures have been done by study in library and Internet sources. On the other hand, the study was a kind of practical research and collecting data has been done by descriptive and correlation method. The initial samples were 2500 employees who worked in Arak municipality, but total number of them was 350 employees. The instrument for collecting data was questionnaire and in statistical analysis section, in order to measure the normality of test, Kolmogorov-Smirnov has been used. Then for analyzing research hypotheses, Pearson correlation coefficient was used for measuring the amount of relationship between organizational justice and self-management. Obtained results of hypotheses indicated that three hypotheses were accepted and also there was positive and meaningful relationship between organizational justice and self-managemen

Simultaneous flexural and punching strengthening of RC slabs according to a new hybrid technique using U-shape CFRP laminates

One of the main concerns related to flat reinforced-concrete (RC) slabs is the slab’s punching capacity. Punching can occur not only due to a deficient transverse reinforcement, but also when the flexural capacity of the slab needs to be increased. To increase the flexural capacity, carbon-fiber-reinforced-polymer (CFRP) composites have been applied according to near-surface-mounted (NSM) or external-bonded-reinforcement (EBR) techniques, while for the punching strengthening CFRP reinforcements have been applied according to embedded-through-section (ETS) technique. To take advantage of strengthening benefits of the NSM and ETS techniques, in the present paper a new type of CFRP laminate of U-shape is used by adopting a novel hybrid technique for the simultaneous flexural and punching strengthening of existing RC slabs. Besides, this hybrid technique aims to provide a better bond performance for the ETS and NSM CFRPs by improving the anchorage conditions. Moreover, a higher resistance to the susceptibility of occurrence of other premature failure modes, like concrete cover delamination, is offered by using this hybrid technique. A 3D nonlinear finite-element (FE) model is developed to simulate the experimental tests by considering the nonlinear behavior of the constituent materials. The experimental program and numerical model are described, and the relevant results are analyzed.The authors acknowledge the financial support provided by QREN (through the Operational Program COMPETE) in the scope of the CutInov Project (n. 38780) involving the Clever Reinforcement Company and the Structural Composites Research group of ISISE-Minho University.info:eu-repo/semantics/publishedVersio

Development of innovative hybrid DHCC-GFRP sandwich panels

Tese de Doutoramento em Engenharia Civil.In this study, a new generation of composite sandwich slab is proposed as a solution for the rehabilitation of slabs in old masonry buildings. The innovative solution proposed includes four components: a Deflection Hardening Cement Composite (DHCC) layer on the top compression skin, a glass fiber reinforced polymer (GFRP) skin at the bottom tension surface, GFRP ribs to transfer shear from top to bottom layers, and foam core for thermal-insulation purposes. The DHCC layer contributes to the load carrying and deflection capacity due to its high stiffness, compressive strength and toughness. It also offers resistance to the occurrence of buckling phenomena in the GFRP ribs, improves the performance of this structural concept against impact and fire, and constitutes an excellent medium for the application of finishing materials, like ceramics or timber. To evaluate the efficiency of the developed innovative slabs, different composite specimens, with various span lengths, were tested under different load conditions, including flexural loading, shear loading, and long term deformation. The obtained results from experimental tests are comprehensively analysed. Advanced numerical simulations on the hybrid slabs are also developed. The influence of considering isotropic or orthotropic behaviour for the GFRP components and linear or nonlinear behaviour for the DHCC is investigated numerically. The results obtained during the experimental tests are used to appraise the performance of the constitutive models adopted in the FEM-based simulations and the quality of the meshes defined. In addition, some analytical models that consider the relation between force and deflection are proposed to evaluate the response of this structural system under static and long-term loadings.Neste trabalho, desenvolve-se uma nova solução de painel sandwich a ser utilizado na substituição de pavimentos existentes em edifícios de alvenaria. A solução proposta consiste num painel sandwich que inclui quatro componentes principais: uma lâmina inferior tracionada, realizada em GFRP, uma camada superior comprimida realizada com argamassa de elevada ductilidade (deflection hardening cement composite - DHCC), almas em GFRP para transmitir esforços de corte entre as duas camadas extremas de GFRP e DHCC e uma camada de espuma de poliuretano, posicionada entre as duas camadas extremas, capaz de garantir um bom comportamento térmico e acústico do painel. A camada de argamassa de elevada ductilidade tem com função contribuir para a capacidade de carga e de deformação do painel, uma vez que é um material que apresenta elevada resistência à compressão e elevado módulo de elasticidade. A camada de argamassa oferece resistência à ocorrência de fenómenos de encurvadura nas almas de GFRP, melhora o desempenho do painel sob ações extremas, como cargas de impacto e fogo, e constitui um excelente meio para a aplicação de materiais de acabamento, tal como os elementos cerâmicos ou a madeira. Para avaliar a eficência da solução desenvolvida, foram fabricados vários provetes, com diferentes vãos, e testados sob o efeito de várias condições de carregamento, onde se incluem situações onde os esforços principais são de flexão, de corte ou resultantes de carregamentos de longa duração. Os parâmetros medidos durante os ensaios experimentais são avaliados e analisados de forma pormenorizada. São também desenvolvidos modelos numéricos baseados no Método dos elementos finitos (FEM), com base na geometria e nas propriedades dos provetes testados experimentalmente. Os modelos desenvolvidos são calibrados com base nos resultados obtidos durante esses ensaios. É avaliada a influência de considerar o comportamento isotrópico ou ortotrópico dos componentes de GFRP e o comportamento linear ou não linear da argamassa de elevada ductilidade (DHCC). Na avaliação do comportamento dos painéis, são considerados requisitos que resultam da verificação de estados limite de serviço e estados limites últimos. Além disso, os resultados obtidos durante os ensaios experimentais são utilizados para avaliar o desempenho dos modelos constitutivos adoptados nas simulações numéricas e a qualidade das malhas adotadas. Complementarmente, são propostos alguns modelos analíticos que consideram a relação entre força e deformação com o objetivo de avaliar a resposta deste sistema estrutural sob efeito de carregamentos estáticos e de longa duração