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Using XFEM technique to predict the damage of unidirectional CFRP composite notched under tensile load

  • Benzaama, A.;Mokhtari, M.;Benzaama, H.;Gouasmi, S.;Tamine, T.
    • Advances in aircraft and spacecraft science
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    • v.5 no.1
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    • pp.129-139
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    • 2018
  • The composite materials are widely used in aircraft structures. Their relative rigidity/weight gives them an important advantage over the metal structures. The objective of this work is to analyze by the finite element method the mechanical behavior of composite plate type notched with various forms under tensile load. Two basic parameters were taken into consideration. The first, the form of the notch in order to see its effect on the stress and the failure load. The second, we studied the influence of the locale orientation of fiber around the plate's notch. These parameters are studied in order to see their effects on the distribution stress and failure load of the plate. The calculation of the failure load is determined numerically with the numerical code ABAQUS using the XFEM (extended Finite Element Modeling) based on the fracture mechanics. The result shows clearly that it is important to optimize the effect of fiber orientation around the notch.

Dynamic knowledge mapping guided by data mining: Application on Healthcare

  • Brahami, Menaouer;Atmani, Baghdad;Matta, Nada
    • Journal of Information Processing Systems
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    • v.9 no.1
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    • pp.1-30
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    • 2013
  • The capitalization of know-how, knowledge management, and the control of the constantly growing information mass has become the new strategic challenge for organizations that aim to capture the entire wealth of knowledge (tacit and explicit). Thus, knowledge mapping is a means of (cognitive) navigation to access the resources of the strategic heritage knowledge of an organization. In this paper, we present a new mapping approach based on the Boolean modeling of critical domain knowledge and on the use of different data sources via the data mining technique in order to improve the process of acquiring knowledge explicitly. To evaluate our approach, we have initiated a process of mapping that is guided by machine learning that is artificially operated in the following two stages: data mining and automatic mapping. Data mining is be initially run from an induction of Boolean case studies (explicit). The mapping rules are then used to automatically improve the Boolean model of the mapping of critical knowledge.

A novel quasi-3D hyperbolic shear deformation theory for vibration analysis of simply supported functionally graded plates

  • Sidhoum, Imene Ait;Boutchicha, Djilali;Benyoucef, Samir;Tounsi, Abdelouahed
    • Smart Structures and Systems
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    • v.22 no.3
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    • pp.303-314
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    • 2018
  • An original quasi-3D hyperbolic shear deformation theory for simply supported functionally graded plates is proposed in this work. The theory considers both shear deformation and thickness-stretching influences by a hyperbolic distribution of all displacements within the thickness, and respects the stress-free boundary conditions on the upper and lower surfaces of the plate without using any shear correction coefficient. By expressing the shear parts of the in-plane displacements with the integral term, the number of unknowns and equations of motion of the proposed theory is reduced to four as against five in the first shear deformation theory (FSDT) and common quasi-3D theories. Equations of motion are obtained from the Hamilton principle. Analytical solutions for dynamic problems are determined for simply supported plates. Numerical results are presented to check the accuracy of the proposed theory.

Glass powder admixture effect on the dynamic properties of concrete, multi-excitation method

  • Kadik, Abdenour;Boutchicha, Djilali;Bali, Abderrahim;Cherrak, Messaouda
    • Structural Engineering and Mechanics
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    • v.74 no.5
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    • pp.671-678
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    • 2020
  • In this work, the dynamic properties of a high performance concrete containing glass powder (GP) was studied. The GP is a new cementitious material obtained by recycling waste glass presenting pozzolanic activity. This eco-friendly material was incorporated in concrete mixes by replacing 20 and 30% of cement. The mechanical properties of building materials highly affect the response of the structure under dynamic actions. First, the resonant vibration frequencies were measured on concrete plate with free boundary conditions after 14, 28 and 90 curing days by using an alternative vibration monitoring technique. This technique measures the average frequencies of several excitations done at different points of the plate. This approach takes into account the heterogeneity of a material like concrete. So, the results should be more precise and reliable. For measuring the bending and torsion resonant frequencies, as well as the damping ratio. The dynamic properties of material such as dynamic elastic modulus and dynamic shear modulus were determined by modelling the plate on the finite element software ANSYS. Also, the instantaneous aroused frequency method and ultrasound method were used to determine the dynamic elastic modulus for comparison purpose, with the results obtained from vibration monitoring technique.

A Novel Framework for Defining and Submitting Workflows to Service-Oriented Systems

  • Bendoukha, Hayat;Slimani, Yahya;Benyettou, Abdelkader
    • Journal of Information Processing Systems
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    • v.10 no.3
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    • pp.365-383
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    • 2014
  • Service-oriented computing offers efficient solutions for executing complex applications in an acceptable amount of time. These solutions provide important computing and storage resources, but they are too difficult for individual users to handle. In fact, Service-oriented architectures are usually sophisticated in terms of design, specifications, and deployment. On the other hand, workflow management systems provide frameworks that help users to manage cooperative and interdependent processes in a convivial manner. In this paper, we propose a workflow-based approach to fully take advantage of new service-oriented architectures that take the users' skills and the internal complexity of their applications into account. To get to this point, we defined a novel framework named JASMIN, which is responsible for managing service-oriented workflows on distributed systems. JASMIN has two main components: unified modeling language (UML) to specify workflow models and business process execution language (BPEL) to generate and compose Web services. In order to cover both workflow and service concepts, we describe in this paper a refinement of UML activity diagrams and present a set of rules for mapping UML activity diagrams into BPEL specifications.

A Novel Approach for Integrating Security in Business Rules Modeling Using Agents and an Encryption Algorithm

  • Houari, Nawal Sad;Taghezout, Noria
    • Journal of Information Processing Systems
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    • v.12 no.4
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    • pp.688-710
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    • 2016
  • Our approach permits to capitalize the expert's knowledge as business rules by using an agent-based platform. The objective of our approach is to allow experts to manage the daily evolutions of business domains without having to use a technician, and to allow them to be implied, and to participate in the development of the application to accomplish the daily tasks of their work. Therefore, the manipulation of an expert's knowledge generates the need for information security and other associated technologies. The notion of cryptography has emerged as a basic concept in business rules modeling. The purpose of this paper is to present a cryptographic algorithm based approach to integrate the security aspect in business rules modeling. We propose integrating an agent-based approach in the framework. This solution utilizes a security agent with domain ontology. This agent applies an encryption/decryption algorithm to allow for the confidentiality, authenticity, and integrity of the most important rules. To increase the security of these rules, we used hybrid cryptography in order to take advantage of symmetric and asymmetric algorithms. We performed some experiments to find the best encryption algorithm, which provides improvement in terms of response time, space memory, and security.

A New Image Clustering Method Based on the Fuzzy Harmony Search Algorithm and Fourier Transform

  • Bekkouche, Ibtissem;Fizazi, Hadria
    • Journal of Information Processing Systems
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    • v.12 no.4
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    • pp.555-576
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    • 2016
  • In the conventional clustering algorithms, an object could be assigned to only one group. However, this is sometimes not the case in reality, there are cases where the data do not belong to one group. As against, the fuzzy clustering takes into consideration the degree of fuzzy membership of each pixel relative to different classes. In order to overcome some shortcoming with traditional clustering methods, such as slow convergence and their sensitivity to initialization values, we have used the Harmony Search algorithm. It is based on the population metaheuristic algorithm, imitating the musical improvisation process. The major thrust of this algorithm lies in its ability to integrate the key components of population-based methods and local search-based methods in a simple optimization model. We propose in this paper a new unsupervised clustering method called the Fuzzy Harmony Search-Fourier Transform (FHS-FT). It is based on hybridization fuzzy clustering and the harmony search algorithm to increase its exploitation process and to further improve the generated solution, while the Fourier transform to increase the size of the image's data. The results show that the proposed method is able to provide viable solutions as compared to previous work.

Occurrence of Leaf Spot Disease Caused by Alternaria crassa (Sacc.) Rands on Jimson Weed and Potential Additional Host Plants in Algeria

  • Bessadat, Nabahat;Hamon, Bruno;Bataille-Simoneau, Nelly;Chateau, Corentin;Mabrouk, Kihal;Simoneau, Philippe
    • The Plant Pathology Journal
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    • v.36 no.2
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    • pp.179-184
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    • 2020
  • A leaf spot pathogen Alternaria sp. was recovered from jimson weed, tomato, parsley, and coriander collected during surveys of blight diseases on Solanaceae and Apiaceae in Algeria. This species produced large conidial body generating long apical beaks that tapered gradually from a wide base to a narrow tip and short conidiophores originating directly from the agar surface. This species exhibited morphological traits similar to that reported for Alternaria crassa. The identification of seven strains from different hosts was confirmed by sequence analyses at the glyceraldehyde-3-phosphate dehydrogenase, RNA polymerase second largest subunit, and translation elongation factor 1-alpha loci. Further the pathogen was evaluated on jimson weed, coriander, parsley, and tomato plants, and this fungus was able to cause necrotic lesions on all inoculated plants. A. crassa is reported for the first time as a new species of the Algerian mycoflora and as a new potential pathogen for cultivated hosts.