Search results for "Systems Engineering"
showing 10 items of 1230 documents
A Survey on Proxy Mobile IPv6 Handover
2016
[EN] As wireless technologies have been improving in recent years, a mobility management mechanism is required to provide seamless and ubiquitous mobility for end users who are roaming among points of attachment in wireless networks. Thus, Mobile IPv6 was developed by the Internet Engineering Task Force (IETF) to support the mobility service. However, Mobile IPv6 is unable to fulfill the requirements of real-time applications, such as video streaming service and voice over IP service, due to its high handover (HO) latency. To address this problem, Proxy Mobile IPv6 (PMIPv6) has been introduced by the IETF. In PMIPv6, which is a network-based approach, the serving network controls mobility m…
A Two-End Traveling Wave Fault Location System for MV Cables
2019
In this paper, a new low-cost device is proposed for fault location in power distribution system. The device is part of a system that should include several units installed in couples at the two ends of medium voltage (MV) cable lines. Their low cost justifies a widespread installation of these devices, moreover other functionalities could be considered so as to enrich the potential of the system for MV cables monitoring and asset management. The system exploits a two-end traveling wave technique, low complexity, and low-cost solutions both for the analog front end as well as for the communication infrastructure. A LoRa network is indeed considered as wireless modulation technique perfectly…
Epistemic uncertainty in fault tree analysis approached by the evidence theory
2012
Abstract Process plants may be subjected to dangerous events. Different methodologies are nowadays employed to identify failure events, that can lead to severe accidents, and to assess the relative probability of occurrence. As for rare events reliability data are generally poor, leading to a partial or incomplete knowledge of the process, the classical probabilistic approach can not be successfully used. Such an uncertainty, called epistemic uncertainty, can be treated by means of different methodologies, alternative to the probabilistic one. In this work, the Evidence Theory or Dempster–Shafer theory (DST) is proposed to deal with this kind of uncertainty. In particular, the classical Fau…
Fall of Potential Measurement of the Earth Resistance in Urban Environments: Accuracy Evaluation
2019
Both Standards EN 50522 and IEEE 81 propose the fall of potential method (FPM) to carry out the measurement of the resistance to earth ( $R_{\text{ES}}$ ) of an earthing system (ES). However, in urban areas, the recommended distances between the ES and auxiliary electrodes are not easy to respect, due to the presence of buildings and tarmac. Furthermore, unknown buried metallic parts and interconnections among ESs could modify the earth potential profile of the area, affecting the measurement results. In this paper, the key-issues that influence the measured $R_{\text{ES}}$ when the FPM is used in an urban environment are presented. A parametric analysis, carried out with Comsol Multiphysic…
Current signature based fault diagnosis of field-oriented and direct torque-controlled induction motor drives
2017
In this article, the operation of three-phase squirrel-cage induction motors is analysed under faulty conditions in closed loop with state-of-the-art controllers, namely, the field-oriented control...
Confidence, tolerance, and allowance in biological engineering: The nuts and bolts of living things
2014
The emphasis of systems and synthetic biology on quantitative understanding of biological objects and their eventual re-design has raised the question of whether description and construction standards that are commonplace in electric and mechanical engineering are applicable to live systems. The tuning of genetic devices to deliver a given activity is generally context-dependent, thereby undermining the re-usability of parts, and predictability of function, necessary for manufacturing new biological objects. Tolerance (acceptable limits within the unavoidable divergence of a nominal value) and allowance (deviation introduced on purpose for the sake of flexibility and hence modularity, i.e. …
Semiactive–passive structural vibration control strategy for adjacent structures under seismic excitation
2012
Abstract The objective of this paper is to study a structural vibration control strategy for seismic protection of multi-structure systems that combines interstructure passive damping elements with local feedback control systems implemented in the substructures. These local feedback control systems are independently designed and operated, and use semiactive devices with limited actuation capacity as force actuators. The combined action of local semiactive feedback control systems and passive interstructure links can produce an appropriate reduction in the substructures' vibrational response and, simultaneously, provides additional protection against interstructure collisions. The proposed s…
Hydraulic vs. Electric: A Review of Actuation Systems in Offshore Drilling Equipment
2016
This article presents a survey on actuation systems encountered in offshore drilling applications. Specifically, it focuses on giving a comparison of hydraulic and electric drivetrains along with detailed explanations of their advantages and drawbacks. A significant number of industrial case studies is examined in addition to the collection of academic publications, in order to accurately describe the current market situation. Some key directions of research and development required to satisfy increasing demands on powertrains operating offshore are identified. The impact of the literature and application surveys is further strengthened by benchmarking two designs of a full-scale pipe handl…
A Simultaneous Approach for IMS Design: a Possibility Based Approach
1999
IMS investments are characterised by high fixed costs and long life cycles. On the other hand, their redditivity and risk coverage depend on their manufacturing efficiency that is mainly defined during the design phase by fixing the system configuration. Due to the flexibility required to IMS, system configuration depends not only from technological information, such as product routing table and service times, but also from marketing data such as the typology of products to be manufacture and their production volumes. Moreover, the evaluation of the redditivity and the risk of the investment depends on market information such as product prices as well. Such interdependencies make the invest…
Modeling the energy and environmental life cycle of buildings: A co-simulation approach
2017
Abstract Building simulation is currently looking towards interdisciplinary experiences, aiming to the integration of simulation tools in different technical domains. At the same time, the interest of the building community to high performance buildings has also strengthened the interest on Life Cycle performances of such buildings, due to the reduction in their operational stage impacts. In this context, the paper proposes an integration of building simulation and Life Cycle Assessment through the programming of a TRNSYS component. It can perform Life Cycle Assessment studies, while having as output as well energy balances and energy and environmental payback times. Currently, the tool is …