Search results for "Systems engineering"
showing 10 items of 1230 documents
Further improvements in the structural analysis of DEMO Divertor Cassette body and design assessment according to RCC-MRx
2019
Abstract This paper presents the enhancements related to the structural analyses of DEMO Divertor in the framework of the EUROfusion Power Plant Physics & Technology (PPPT) program. This activity started two years ago and its preliminary results were published in previous papers. It has been divided in some areas defined by the similarity of the matters they contain: the structural analysis, of utmost importance, has been preceded by a preliminary phase, like the geometry definition or the thermal and the electric-magnetic analysis for loads evaluation; then the structural analysis has been finally confirmed with further evaluations related to excessive deformation or plastic instability. T…
PRISMA: towards quality, aspect oriented and dynamic software architectures
2003
The development of software systems must be done using platforms that allow the description of quality, complex, distributed, dynamic and reusable architectural models. We present in this paper PRISMA, an architectural modelling approach based on aspects and components that uses a component definition language (components, connectors and systems) to define architectural types at a high abstraction level and a configuration language to design the architecture of software systems. The component definition language increases reuse allowing importation of COTS and reduces complexity by integrating two modern software development approaches: component-based software development and aspect-orient…
Frequency dynamics of power systems with temporally distributed disturbances
2021
Abstract The frequency dynamics and stability of power systems is essentially affected by nature and characteristics of the disturbances occurring in the system. Conventionally, frequency transients are examined assuming a single disturbance applied at a given time. However, actual incidents in the power systems can be generally composed of a temporal sequence of events, and thus characterized by multiple power imbalances of different magnitudes and time offsets. The consideration of the effects of the temporal distribution of power imbalances is important for two main reasons: the impact on the frequency dynamics of the system in terms of frequency metrics such as minimum instantaneous fre…
Decentralization and heterogeneity in complex adaptative systems
2015
Purpose – Following a bacterial-based modeling approach, the authors want to model and analyze the impact of both decentralization and heterogeneity on group behavior and collective learning. The paper aims to discuss these issues. Design/methodology/approach – Inspired by bacterial conjugation, the authors have defined an artificial society in which agents’ strategies adapt to changes in resources location, allowing migration, and survival in a dynamic sugarscape-like scenario. To study the impact of these variables the authors have simulated a scenario in which resources are limited and localized. The authors also have defined three constraints in genetic information processing (inhibiti…
Towards flexible process support with a CASE shell
1994
CASE technology for improving information systems development (ISD) is mostly based on the creation and verification of IS models using a fixed set of techniques. However, ISD is a complex activity, which requires well selected and suited methodologies and development practices for different situations. This calls for CASE shells (metaCASE environments) in which the methodologies can be tailored. Further, the quality of produced deliverables (e.g. specifications and models) is dependent on the development process. The focus of this paper is on integrating a flexible process support into a CASE shell. The ISD process is specified using a graphical process model, the purposes of which are the…
A Conceptual Model of Product Design
2013
The paper presents a conceptual model that pursues the understanding of the activities, the phases and the mechanisms of product design. The purpose of this model is to aid the product conception phase, as well as to develop software products that can furthermore aid design. The model takes into account the entire mental potential of the human being. The paper uses Jung's model in order to describe the various aspects of the human psyche. The paper presents a number of design models from the scientific literature. The proposed model defines domains of the needs imposed by stakeholders and specialists, functions domains and product domains. It explains the mechanism through which information…
The linear saturated decentralized strategy for constrained flow control is asymptotically optimal
2013
We present an algorithm for constrained network flow control in the presence of an unknown demand. Our algorithm is decentralized in the sense that it is implemented by a team of agents, each controlling just the flow on a single arc of the network based only on the buffer levels at the nodes at the extremes of the arc, while ignoring the actions of other agents and the network topology. We prove that our algorithm is also stabilizing and steady-state optimal. Specifically, we show that it asymptotically produces the minimum-norm flow. We finally generalize our algorithm to networks with a linear dynamics and we prove that certain least-square optimality properties still hold.
Neural network approach to solving fuzzy nonlinear equations using Z-numbers
2020
In this article, the fuzzy property is described by means of the Z-number as the coefficients and variables of the fuzzy equations. This alteration for the fuzzy equation is appropriate for system modeling with Z-number parameters. In this article, the fuzzy equation with Z-number coefficients and variables is tended to be used as the models for the uncertain systems. The modeling issue related to the uncertain system is to obtain the Z-number coefficients and variables of the fuzzy equation. Nevertheless, it is extremely hard to get the Z-number coefficients of the fuzzy equations. In this article, in order to model the uncertain nonlinear systems, a novel structure of the multilayer neura…
Performance Analysis of Synchronous Duty-Cycled MAC Protocols
2015
In this letter, we propose an analytical model to evaluate the performance of the S-MAC protocol. The proposed model improves the accuracy of previous models in two aspects. First, it incorporates the dependence among the nodes within a cluster by defining a DTMC that models the number of active nodes, whereas the previous models considered that nodes were mutually independent. Second, it proposes new methods for calculating packet delay and energy consumption. The analytical model is validated through discrete-event based simulations. Numerical results demonstrate that the proposed analytical model and methods yield accurate results under realistic assumptions
Study and simulation of photovoltaic installation connected to the grid with storage system
2016
In the present paper, a new approach to the management of energy resources in a research laboratory is proposed and evaluated by a simulation for the PV installation realized for the Tunisian-Italian cooperation project DE.DU.ENER.T, using renewable energy and economic criteria. The aim of this project is to improve energy efficiency order to minimize the electricity cost consumed at the laboratory, because according to the bills of electricity received we noticed that there is a high consumption of electrical current, from the STEG grid, and especially by the energy intensive equipment such as drying ovens and all the workstations. So we targeted to install a photovoltaic field of 12KWc to…