The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Andreas Nilsson - One of the best experts on this subject based on the ideXlab platform.

  • Palaeomagnetic secular variations in the varved sediments of lake Gościąż, Poland : testing the stability of the natural remanent magnetization and validity of relative palaeointensity estimates
    2006
    Co-Authors: Andreas Nilsson
    Abstract:

    The pseudo-Thellier technique was applied to recover relative palaeointensity (PT-RPI) estimates from four core sections, each 2 m in length, obtained from Lake Gościąz, Poland. The varve chronology from Lake Gościąz, originally constructed by Tomasz Goslar, was transferred to the sediment sequence. The chronology was extrapolated to cover the upper parts containing a less pronounced varve structure. The aim of the study was to evaluate the stability of the natural remanent magnetization and validity of relative palaeointensity estimates. The alternating field (AF) demagnetization measurements showed the presence of two or possibly three stable NRM carriers. It was established via the pseudo-Thellier technique that the sediments were not suitable for reconstruction of palaeointensity. The principal Component analysis technique (PCA) was used to estimate the best fit inclination and declination on a vector Component Diagram. The data were evaluated and rejected based on the line fit coherency and the angle with which it diverges from the origin. All declination data were rejected due to very high scatter. The resulting inclination curve was compared to a previous study of Lake Gościąz, the output of a geomagnetic model (CALS7K.2) and a Northern Sweden PSV master curve. A significant inclination divergence taking place between 1500 and 500 BC was identified between the CALS7K.2 model and the Northern Sweden master curve. Both Gościąz data sets show similar trends as the CALS7K.2 model, supporting the notion that the divergence is real and of regional character.

  • palaeomagnetic secular variations in the varved sediments of lake gościąz poland testing the stability of the natural remanent magnetization and validity of relative palaeointensity estimates
    Dissertations in Geology at Lund University; (2006), 2006
    Co-Authors: Andreas Nilsson
    Abstract:

    The pseudo-Thellier technique was applied to recover relative palaeointensity (PT-RPI) estimates from four core sections, each 2 m in length, obtained from Lake Gościąz, Poland. The varve chronology from Lake Gościąz, originally constructed by Tomasz Goslar, was transferred to the sediment sequence. The chronology was extrapolated to cover the upper parts containing a less pronounced varve structure. The aim of the study was to evaluate the stability of the natural remanent magnetization and validity of relative palaeointensity estimates. The alternating field (AF) demagnetization measurements showed the presence of two or possibly three stable NRM carriers. It was established via the pseudo-Thellier technique that the sediments were not suitable for reconstruction of palaeointensity. The principal Component analysis technique (PCA) was used to estimate the best fit inclination and declination on a vector Component Diagram. The data were evaluated and rejected based on the line fit coherency and the angle with which it diverges from the origin. All declination data were rejected due to very high scatter. The resulting inclination curve was compared to a previous study of Lake Gościąz, the output of a geomagnetic model (CALS7K.2) and a Northern Sweden PSV master curve. A significant inclination divergence taking place between 1500 and 500 BC was identified between the CALS7K.2 model and the Northern Sweden master curve. Both Gościąz data sets show similar trends as the CALS7K.2 model, supporting the notion that the divergence is real and of regional character.

Mert Ozkaya - One of the best experts on this subject based on the ideXlab platform.

  • FedCSIS - Towards Extending UML’s Activity Diagram for the Architectural Modeling, Analysis, and Implementation
    Proceedings of the 2020 Federated Conference on Computer Science and Information Systems, 2020
    Co-Authors: Mehmet Alp Kose, Mert Ozkaya
    Abstract:

    SAWUML is a general-purpose software modeling language that extends UML by unifying Component and sequence Diagrams for the specifications of software architectures. While Component Diagram is used for modeling the system structures, sequence Diagram is extended with the Design-by-Contract approach for the modeling of system behaviors. In this paper, we aim at enhancing the language usability by providing alternative modeling choices for practitioners. To this end, we extended SAWUML’s notation set with UML’s activity Diagram for the behavior modeling. So, practitioners may now use either sequence or activity Diagrams, while the system structures are still modeled with Component Diagrams. We also extended SAWUML’s modeling editor for creating software architecture models together with Component and activity Diagrams and the code generators for automatically obtaining (i) formal models in SPIN’s ProMeLa for formal verification and (ii) Java-based implementation. We illustrate our language extension with the gas station case-study.

  • A survey on the practical use of UML for different software architecture viewpoints
    Information and Software Technology, 2020
    Co-Authors: Mert Ozkaya, Ferhat Erata
    Abstract:

    Abstract Context Software architecture viewpoints modularize the software architectures in terms of different viewpoints that each address a different concern. Unified Modeling Language (UML) is so popular among practitioners for modeling software architectures from different viewpoints. Objective In this paper, we aimed at understanding the practitioners’ UML usage for the modeling of software architectures from different viewpoints. Method To this end, 109 practitioners with diverse profiles have been surveyed to understand practitioners’ UML usage for six different viewpoints: functional, information, concurrency, development, deployment, and operational. Each viewpoint has been considered in terms of a set of software models that can be created in that viewpoint. Results The survey includes 35 questions for different viewpoint models, and the results lead to interesting findings. While the top popular viewpoints for the UML-based software architecture modeling are the functional (96%) and information (99%) viewpoints, the least popular one is the operational viewpoint that is considered by 26% of the practitioners. The top popular UML modeling tool is Enterprise Architect regardless of the viewpoints considered. Concerning the software models that can be created in each viewpoint, UML’s class Diagram is practitioners’ top choice for the functional structure (71%), data structure (85%), concurrency structure (75%), software code structure (34%), and system installation (39%), and system support (16%) models; UML’s sequence Diagram is the top choice for the data lifecycle models (47%); UML’s deployment Diagram for the physical structure (71%), mapping between the functional and physical Components (53%), and system migration (21%) models; UML’s activity Diagram for the data flow (65%), software build and release processes (20–22%), and system administration (36%) models; UML’s Component Diagram for the mapping between the functional and concurrent Components (35%), software module structure (47%), and system configuration (21%) models; and UML’s package Diagram for the software module structure (47%) models.

  • Visual Specification and Analysis of Contract-Based Software Architectures
    Journal of Computer Science and Technology, 2017
    Co-Authors: Mert Ozkaya
    Abstract:

    XCD is a design-by-contract based architecture description language that supports modular specifications in terms of Components and connectors (i.e., interaction protocols). XCD is supported by a translator that produces formal models in SPIN’s ProMeLa formal verification language, which can then be formally analysed using SPIN’s model checker. XCD is extended with a visual notation set called VXCD. VXCD extends UML’s Component Diagram and adapts it to XCD’s structure, contractual behaviour, and interaction protocol specifications. Visual VXCD specifications can be translated into textual XCD specifications for formal analysis. To illustrate VXCD, the well-known gas station system is used. The gas system is specified contractually using VXCD’s visual notation set and then formally analysed using SPIN’s model checker for a number of properties including deadlock and race-condition.

Ferhat Erata - One of the best experts on this subject based on the ideXlab platform.

  • A survey on the practical use of UML for different software architecture viewpoints
    Information and Software Technology, 2020
    Co-Authors: Mert Ozkaya, Ferhat Erata
    Abstract:

    Abstract Context Software architecture viewpoints modularize the software architectures in terms of different viewpoints that each address a different concern. Unified Modeling Language (UML) is so popular among practitioners for modeling software architectures from different viewpoints. Objective In this paper, we aimed at understanding the practitioners’ UML usage for the modeling of software architectures from different viewpoints. Method To this end, 109 practitioners with diverse profiles have been surveyed to understand practitioners’ UML usage for six different viewpoints: functional, information, concurrency, development, deployment, and operational. Each viewpoint has been considered in terms of a set of software models that can be created in that viewpoint. Results The survey includes 35 questions for different viewpoint models, and the results lead to interesting findings. While the top popular viewpoints for the UML-based software architecture modeling are the functional (96%) and information (99%) viewpoints, the least popular one is the operational viewpoint that is considered by 26% of the practitioners. The top popular UML modeling tool is Enterprise Architect regardless of the viewpoints considered. Concerning the software models that can be created in each viewpoint, UML’s class Diagram is practitioners’ top choice for the functional structure (71%), data structure (85%), concurrency structure (75%), software code structure (34%), and system installation (39%), and system support (16%) models; UML’s sequence Diagram is the top choice for the data lifecycle models (47%); UML’s deployment Diagram for the physical structure (71%), mapping between the functional and physical Components (53%), and system migration (21%) models; UML’s activity Diagram for the data flow (65%), software build and release processes (20–22%), and system administration (36%) models; UML’s Component Diagram for the mapping between the functional and concurrent Components (35%), software module structure (47%), and system configuration (21%) models; and UML’s package Diagram for the software module structure (47%) models.

Fereidoon Shams - One of the best experts on this subject based on the ideXlab platform.

  • Modeling of Component Diagrams Using Petri Nets
    Indian journal of science and technology, 2010
    Co-Authors: Sima Emadi, Fereidoon Shams
    Abstract:

    With the growing use of UML Diagrams for software architecture description and the importance of non-functional requirements evaluation at software architecture level, filling the scientific gap between architect and requirement analyst is considered to be significant. Software architects are not usually familiar with non-functional requirement analysis and are not able to analyze such requirements easily. On the other hand, non-functional requirements cannot be evaluated directly by UML Diagrams. Therefore, the architect should annotate additional information of the nonfunctional requirements to software architecture description and then an executable model can be produced. These executable models can be petri nets, queuing networks, stochastic process algebra and etc. One kind of the UML Diagrams that can be used to describe software architecture is Component Diagram. In this paper, we propose a new algorithm that enables an architect to transform a Component Diagram into an executable model based on different extensions of petri nets. Moreover, we show how to use this petri net model for performance evaluation and simulation and the implications of this transformation are described completely. Finally, to represent the usage of our proposed algorithm, we consider a case study as an example.

  • From UML Component Diagram to an executable model based on Petri Nets
    2008 International Symposium on Information Technology, 2008
    Co-Authors: Sima Emadi, Fereidoon Shams
    Abstract:

    With the growing use of UML Diagrams for software architecture description and the importance of evaluating non-functional requirement in software architecture level, providing an executable model of these Diagrams seems to be significant. But on one hand software designers are not familiar with the non-functional requirements analysis and are unable to analyze such requirement easily and on the other hand non-functional requirements can not be evaluated directly by UML Diagrams. Therefore, this evaluation should be added to the Diagrams. In order to do that, an executable model of software architecture should be provided. These executable models can be Petri net, queuing network, stochastic process algebra and etc. In this paper, the primary assumption is that software architecture is described by UML Diagrams and then the role of Component Diagram on performance evaluation is studied. Ultimately through algorithm, it is transformed into an executable model, called Petri Net (PN).

Aldaléa L. B. Marques - One of the best experts on this subject based on the ideXlab platform.

  • Oxidative stability of biodiesel by mixture design and a four-Component Diagram
    Fuel, 2018
    Co-Authors: Isabelle Moraes Amorim Viegas, Alex Oliveira Barradas Filho, Edmar P. Marques, Claudete Fernandes Pereira, Aldaléa L. B. Marques
    Abstract:

    Abstract Some biodiesels originating mainly from unsaturated feedstocks such as soybean, rapeseed, corn and sunflower do not reach the minimum oxidative stability of 8 h, as specified by standard EN 14214. An alternative to work with this type of biodiesels is to prepare their mixture with others biodiesels that are mainly saturated. This work presents a study employing binary, ternary and quaternary mixtures of biodiesels from soybean, corn, babassu and palm, aiming to improve the oxidative stability by using mixture design and polynomial modeling. For this, 71 mixtures were designed by simplex-lattice and simplex-centroid designs and divided into a calibration set (50 samples) and an external validation set (21 samples) employing the partitioning method based on joint X-y distances (algorithm SPXY). Six polynomials for quaternary mixtures models were built and statistically compared. The quadratic equation achieved the best results, with correlation coefficients (r) 0.9879 and 0.9569 for calibration and validation steps, respectively. Root mean square errors (RMSE) were 0.67 h for calibration and 0.71 h for validation and mean absolute percentage errors (MAPE) were 5.07% and 7.54% for calibration and validation, respectively. The quadratic equation was used to plot the contour maps for the oxidative stability resulting in a new way to represent four-Component Diagrams. In addition, a variety of possible biodiesel mixtures (binary, ternary and quaternary) are presented from babassu, soybean, corn and/or palm that meet any oxidative stability specifications within the range of 5.08 h–20.88 h, depending on the availability of the type and amount of the feedstock and target oxidative stability.