Search results for "Computer Networks"
showing 10 items of 860 documents
H∞ static output-feedback control design with constrained information for offshore wind turbine system
2013
Abstract This paper deals with H ∞ static output-feedback control design with constrained information for offshore wind turbines. Constrained information indicates that a special zero–nonzero structure is imposed on the static output-feedback gain matrix. A practical use of such an approach is to design a decentralized controller for a wind turbine. This will also benefit the controller in such a way that it is more tolerant to sensor failure. Furthermore, the model under consideration is obtained by using the wind turbine simulation software FAST. Sufficient conditions to design an H ∞ controller are given in terms of Linear Matrix Inequalities ( LMI s ). Simulation results are given to il…
A Novel Wideband MIMO Car-to-Car Channel Model Based on a Geometrical Semi-Circular Tunnel Scattering Model
2016
In this paper, we present a wideband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on a geometrical semi-circular tunnel (SCT) scattering model. From the geometrical SCT scattering model, a reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. In the proposed reference channel model, it is assumed that an infinite number of scatterers are randomly distributed on the tunnel wall. Starting from the geometrical scattering model, the time-variant transfer function (TVTF) is derived, and its correlation properties in time, frequency, and space are studied. Expressions ar…
From technology engineering to social engineering
2007
Virtual worlds have a long history, and it also includes various technologies. Yet research interest towards them has diverged over the years. It seems that nowadays they are on focus again with the evolution of socially oriented and community-supporting virtual worlds. Instead of technical factors, human factors and the motivation behind the use are highlighted. In this paper, we will briefly review the research efforts made in the 90's, and derive a set of themes that were of interest back then. Next, we will expand the set by arguing for newer themes, identified in the latest information systems literature. These two sets of themes form a basis of a research agenda for studying virtual w…
Welcome to MTI—A New Open Access Journal Dealing with Blue Sky Research and Future Trends in Multimodal Technologies and Interaction
2016
In this era of massive use of computers and other computational devices (e.g., low-cost wearable sensors, smartphones, other smart devices, etc.), the nature of digital data is becoming more complex and heterogeneous.
THE METAMODEL: A STARTING POINT FOR DESIGN PROCESSES CONSTRUCTION
2010
The construction of ad-hoc design processes following the Situational Method Engineering (SME) paradigm is currently carried out by adopting a set of phases for which, until now, no well defined techniques and guidelines have been established. The consequence is that organizations are very dependent on method designers' skills. In this paper, we propose an approach based on SME for constructing customized agent oriented design processes. Our approach adopts the metamodel as the most important factor leading to the selection and assembly of method fragments and an algorithm for establishing the instantiation order of metamodel elements. The algorithm makes the proposed approach repeatable a…
A simulation model for electromagnetic transients in lightning protection systems
2002
This paper deals with the evaluation of electromagnetic transients in a lightning protection system (LPS). A field approach is used, based on the numerical solution of a modified version of the thin-wire electric field integral equation in the frequency domain. Time profiles of interesting electromagnetic quantities are computed by using a discrete fast Fourier transform algorithm. The model takes into account coupling effects among aerial parts and ground electrodes in order to correctly estimate the quantities which can determine electromagnetic hazard inside the LPS; transient touch and step voltages can be easily evaluated also taking into account the human body presence on the soil sur…
Low-cost underwater navigation systems by multi-pressure measurements and AHRS data
2017
This paper deals with accurate navigation for underwater remotely operated vehicles. A feasibility study for a multi-pressure device to be mounted on an ROV is presented. The device can provide accurate estimates of a ROV orientation and angular speed. It is based on the well-known total pressure principle, also used in a Pitot tube, and allows reconstruction of static and dynamic pressures, which in turn provide good estimates of the ROV's orientation and rotational speed, respectively. An appealing feature of the proposed device is its ability to provide accurate estimates even for low-speed movements.
Situation Understanding for Operational Art in Cyber Operations
2016
This paper presents a theoretically motivated framework and methodology that has been designed for finding out the emergent phenomena and information needs for planning and decision-making. The approach is based on complexity thinking, system modeling, communication and cognition philosophy, social system theories and content analysis research technique. It provides results with the analysis of quite small sets of information. The paper demonstrates the approach with a case study. The study was performed in an international cyber experiment of the Multinational Capability Development Campaign (MCDC) 2013-2014. The case study shows that the proposed approach is plausible for increasing under…
How is Building Information Modeling Influenced by Project Complexity?
2014
Virtual design and construction of buildings and architectural spaces require extensive collaboration among a diverse set of design professionals. The authors analyze e-collaboration performance in two construction projects of differing complexity, to gain an understanding of how collaborative design based on building information modeling (BIM) is influenced by the complexity of the building project. The findings suggest that the perceived business value of BIM depends on project complexity and that BIM-based collaboration does not yield unconditional positive implications for all types of construction projects. The authors argue that current practice would benefit from a more structured ap…
Capacity Upper Bound of Channel Assembling in Cognitive Radio Networks with Quasistationary Primary User Activities
2013
In cognitive radio networks (CRNs) with multiple channels, various channel-assembling (ChA) strategies may be applied to secondary users (SUs), resulting in different achieved capacity. However, there is no previous work on determining the capacity upper bound (UB) of ChA for SUs under given system configurations. In this paper, we derive the maximum capacity for CRNs with ChA through Markov chain modeling, considering that primary user (PU) activities are relatively static, compared with SU services. We first deduce a closed-form expression for the maximum capacity in a dynamic ChA strategy and then demonstrate that no other ChA strategy can provide higher capacity than that achieved by th…