concrete system
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Author(s):  
Csaba Varga

As to the conceptualisation of any one institution, the apparently identical notional term can cover four types of institutional systems: (1) the actually existing concrete system, which is a unit that functions as it is (e.g., constitutional system of liberalism as practised in a given area in a given time, e.g., in the United States nowadays); (2) the historically developed concrete system which is a unit that functions as it has been (e.g., constitutional system of liberalism as practised in a given area in a given period, e.g., in the United States since the time it developed); (3) the generalisation of the historically concrete systems as developed in our civilisation (e.g., the constitutional system of liberalism as known and practised in our civilisation); and (4) the core idea of the functioning underlying all kinds of generalisation (e.g., the abstract universal formulation of the ultimate principles of operation, of which the constitutional system of liberalism is but one of the theoretically possible forms of realisation). Within a quasi monographic analysis of them, both their role as a normative ideology and their actual objectivity and contingency are treated.


2021 ◽  
Vol 24 (4) ◽  
pp. 1-28
Author(s):  
Abbas Acar ◽  
Shoukat Ali ◽  
Koray Karabina ◽  
Cengiz Kaygusuz ◽  
Hidayet Aksu ◽  
...  

As many vulnerabilities of one-time authentication systems have already been uncovered, there is a growing need and trend to adopt continuous authentication systems. Biometrics provides an excellent means for periodic verification of the authenticated users without breaking the continuity of a session. Nevertheless, as attacks to computing systems increase, biometric systems demand more user information in their operations, yielding privacy issues for users in biometric-based continuous authentication systems. However, the current state-of-the-art privacy technologies are not viable or costly for the continuous authentication systems, which require periodic real-time verification. In this article, we introduce a novel, lightweight, <underline>p</underline>rivacy-<underline>a</underline>ware, and secure <underline>c</underline>ontinuous <underline>a</underline>uthentication protocol called PACA. PACA is initiated through a password-based key exchange (PAKE) mechanism, and it continuously authenticates users based on their biometrics in a privacy-aware manner. Then, we design an actual continuous user authentication system under the proposed protocol. In this concrete system, we utilize a privacy-aware template matching technique and a wearable-assisted keystroke dynamics-based continuous authentication method. This provides privacy guarantees without relying on any trusted third party while allowing the comparison of noisy user inputs (due to biometric data) and yielding an efficient and lightweight protocol. Finally, we implement our system on an Apple smartwatch and perform experiments with real user data to evaluate the accuracy and resource consumption of our concrete system.


2021 ◽  
Vol 5 (6) ◽  
pp. 2068-2083
Author(s):  
Cynthia Rodrigues Silveira ◽  
Emanuela Mendes Aguiar Santos ◽  
Walkíria Pederiva Ferreira ◽  
Ana Paula Klaus Locatelli

As condições habitacionais precárias do Brasil se encontram em situação alarmante há anos, apresentando dados de déficit habitacional cada vez mais crescente, seja por condições inadequadas de moradias, por localização em zonas de risco, por famílias de baixa renda que tem que pagar aluguel e até mesmo por pessoas que se instalam nas ruas dos centros urbanos. A alta demanda decorrente desse problema social requer a utilização de sistemas construtivos eficientes, produtivos, econômicos, seguros, duráveis e racionalizados, como é o caso de sistemas industrializados, como o concreto PVC, que apresenta uma produtividade oito vezes maior que o método convencional. O objetivo desse estudo é realizar um comparativo entre o método de construção convencional e o Concreto PVC como potenciais técnicas para aplicação nesse tipo de habitação. O estudo possui abordagem qualitativa do tipo aplicada exploratória, sendo realizada através de pesquisa bibliográfica, onde foram reunidas informações sobre ambos os métodos e apresentados de forma comparativa. Os dados coletados foram analisados através da fundamentação teórica apresentada, permitindo a comparação indutiva dos sistemas analisados para aplicação em HIS. A análise verificou que o concreto PVC oferece todas as características essenciais para construção de HIS, apresentando maiores benefícios que o método tradicionalmente utilizado, a alvenaria comum, podendo ser considerada ideal para esse tipo de utilização.


2021 ◽  
Vol 244 ◽  
pp. 112699
Author(s):  
Daniel de Lima Araújo ◽  
Sérgio Azevedo Coelho ◽  
Sylvia Regina Mesquita de Almeida ◽  
Mounir Khalil El Debs

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5421
Author(s):  
Hongjian Ding ◽  
Quansheng Sun ◽  
Yanqi Wang ◽  
Dongzhe Jia ◽  
Chunwei Li ◽  
...  

In view of the problems of traditional repair materials for anchorage concrete of expansion joints, such as ease of damage and long maintenance cycles, the design of polyurethane concrete was optimized in this article, which could be used for rapid repair of concrete in anchorage zone of expansion joints. A new type of carbon fiber grid–polyurethane concrete system was designed, which makes the carbon fiber grid have an excellent synergistic effect with the quick-hardening and high-strength polyurethane concrete, and improved the flexural bearing capacity of the polyurethane concrete. Through the four-point bending test, the influence of the parameters such as the number of grid layers, grid width, and grid density on the flexural bearing capacity of polyurethane concrete beams was tested. The optimum preparation process parameters of carbon fiber grid were obtained to improve the flexural performance of polyurethane concrete. Compared with the Normal specimen, C-80-1’s average flexural strength increased by 47.7%, the failure strain along the beam height increased by 431.1%, and the failure strain at the bottom of the beam increased by 68.9%. The best width of the carbon fiber grid was 80 mm, and the best number of reinforcement layers was one layer. The test results show that the carbon fiber grid could improve the flexural bearing capacity of polyurethane concrete. The carbon fiber grid–polyurethane concrete system provides a new idea for rapid repair of the anchorage zone of bridge expansion joints, and solves the problems such as ease of damage and long maintenance cycles of traditional repair materials, which can be widely used in the future.


2021 ◽  
Vol 242 ◽  
pp. 112585
Author(s):  
Daniel de Lima Araújo ◽  
Edilene Muniz de Oliveira ◽  
Erika Meire Oliveira Silva ◽  
Sérgio Azevedo Coelho ◽  
Mounir Khalil El Debs

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 565
Author(s):  
Changbo Liu ◽  
Zhendong Qian ◽  
Yang Liao ◽  
Haisheng Ren

This study aims to evaluate the economy of a steel bridge deck pavement scheme (SBDPS) using a comprehensive life-cycle cost (LCC) analysis approach. The SBDPS are divided into the “epoxy asphalt concrete system”(EA system) and“ Gussasphalt concrete system”(GA system) according to the difference in the material in the lower layer of the SBDPS. A targeted LCC checklist, including manager cost and user cost was proposed, and a Markov-based approach was applied to establish a life-cycle performance model with clear probability characteristics for SBDPS. Representative traffic conditions were designed using a uniform design method, and the LCC of SBDPS under representative traffic conditions and different credibility (construction quality as a random factor) was compared. The reliability of the LCC analysis approach was verified based on the uncertainty analysis method. Based on an expert-scoring approach, a user cost weight was obtained to ensure it is considered reasonably in the LCC analysis. Compared with the cumulative traffic volume, the cumulative equivalent single axle loads (CESAL) have a closer relationship with the LCC. The GA system has better LCC when the CESAL is less, while the EA system is just the opposite. The breaking point of CESAL for the LCC of the EA system and the GA system is 15 million times. The LCC analysis of SBDPS should consider the influence of random factors such as construction quality. The comprehensive LCC analysis approach in this paper can provide suggestions for bridge-management departments to make a reasonable selection on SBDPS.


2021 ◽  
Vol 272 ◽  
pp. 121971
Author(s):  
Qing Chen ◽  
Rui Ma ◽  
Haoxin Li ◽  
Zhengwu Jiang ◽  
Hehua Zhu ◽  
...  

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