Search results for "Computer network"
showing 10 items of 1634 documents
A comparative analysis of two immersive virtual reality systems in the integration and visualization of natural hand interaction
2022
AbstractIt is generally accepted that the use of natural interaction provides a positive impact in Virtual Reality (VR) applications. Therefore, it is important to understand what is the best way to integrate and visualize this feature in VR. For this reason, this paper presents a comparative study of the integration of natural hand interaction in two immersive VR systems: a Cave Audio Visual Experience (CAVE) system –where users’ real hands are visible– and a non-see-through Head-Mounted Display (HMD) system –where only a virtual representation of the hands is possible–. In order to test the suitability of using this type of interaction in a CAVE and compare it to an HMD, we raise six rese…
Handover and Uplink Power Control Performance in the 3.84 Mcps TDD mode of UTRA Network
2003
In this article we consider the performance of the 3.84 Mcps time-division duplex (TDD) mode of UTRA (Universal Terrestrial Radio Access) network. We emphasize two of the radio resource management algorithms, handover and uplink power control, whose role in the overall system performance is studied extensively. First, a handover algorithm used in WCDMA (Wideband Code Division Multiple Access) standard is considered in a TDD-mode operation. This gives rise to a careful setting of different handover parameters, and the evaluation of the effects to the system performance. Secondly, the specified uplink power control algorithm is considered. Since it is based on several user-made measurements w…
A fog-assisted system to defend against Sybils in vehicular crowdsourcing
2022
Technological advancements in vehicular transportation systems have led to the growth of novel paradigms, in which vehicles and infrastructures collaborate to infer high-level knowledge about phenomena of interest. Vehicular Social Network (VSN) is one such paradigm in which vehicular network entities are considered as part of an Online Social Network (OSN), paving the way for new services derived from social context. Although vehicular crowdsourcing has tremendous benefits, its deployment in real systems requires to solve important challenges including defense against Sybil attacks. This paper proposes a novel fog-assisted system that uses SybilDriver to minimize the presence of Sybil enti…
Spectrum cartography techniques, challenges, opportunities, and applications: A survey
2021
The spectrum cartography finds applications in several areas such as cognitive radios, spectrum aware communications, machine-type communications, Internet of Things, connected vehicles, wireless sensor networks, and radio frequency management systems, etc. This paper presents a survey on state-of-the-art of spectrum cartography techniques for the construction of various radio environment maps (REMs). Following a brief overview on spectrum cartography, various techniques considered to construct the REMs such as channel gain map, power spectral density map, power map, spectrum map, power propagation map, radio frequency map, and interference map are reviewed. In this paper, we compare the pe…
Acceptance of Online Health Services for Self-Help in the Context of Mental Health : Understanding Young Adults Experiences
2018
This paper explores the understanding of the acceptance of online health services from a selfhelp perspective in the context of mental health. By examining the experiences of young adults, this paper develops a framework to leverage the current understanding of the factors that would support the acceptance and use of these types of services. To this end, a multidisciplinary perspective incorporating knowledge from the service marketing, health, and information systems literature is used. The results suggest that the production of online services that are meant for self-help purposes necessitates a focus on the acceptance of technology and, more importantly, instrumental value creation, as t…
Communities of Communication: Making Sense of the “Social” in Social Media
2012
As social media usage permeates people's lives, an increasing portion of their daily behavior leaves digital traces to be used by researchers. Social scientists can hope to gain new insight into the previously hidden but digitally recorded aspects of our digital social lives. Beyond aggregate and individual-level studies of user behavior, the digital traces also enable scientific examination of the structure of social interaction through networks. At the same time, the large scale and networked nature of social media data pose a new set of challenges to be overcome through the development of sound methodologies. We take stock of current methodological promises and challenges in social media…
Remote ECG Monitoring by ECG247 Smart Heart Sensor
2022
Background. Heart rhythm disorders are common and may be associated with serious complications. The quality of the ECG signal is crucial to detect and classify arrhythmias. Most available devices for assessment arrhythmias do not allow for remote monitoring. The Norwegian ECG247 Smart Heart Sensor is a new remote patch monitor developed to simplify the assessment of arrhythmias. This study was aimed at evaluating the quality of the ECG signal from the ECG247 Smart Heart Sensor compared to standard 12-lead ECG. Methods. ECG recordings with ECG247 Smart Heart Sensor and a standard 12-lead ECG recorder were performed in 97 volunteers at Sorlandet Hospital, Arendal, Norway, in 2019. All ECGs we…
Full modal analysis of confocal coaxial elliptical waveguides
2000
An efficient method for analysing confocal coaxial elliptical waveguides is presented. Using elliptical coordinates, the differential Helmholtz equation is transformed into a linear matrix eigenvalue problem by means of the method of moments. The expressions of the vector mode functions for the full spectrum of these guides are constructed, including the TEM, TM and TE modes. The convergence of the method is very good, giving an efficient and accurate code. Comparisons with numerical results found in the technical literature validate the presented theory.
Decoupled Downlink-Uplink Coverage Analysis with Interference Management for Enriched Heterogeneous Cellular Networks
2016
Heterogeneous cellular networks (HetCNets) offer a promising solution to cope with the current cellular coverage crunch. Due to the large transmit power disparity, while following maximum power received (MPR) association scheme, a larger number of users are associated with macro-cell BS (MBS) than small-cell BSs (SBSs). Therefore, an imbalance load arrangement takes place across the HetCNets. Hence, using cell range expansion-based cell association, we can balance the load across the congested MBS. However, using MPR association scheme, users’ offloading leads to two challenges: 1) macro-cell interference , in which the MBS interferes with the offloaded users, and 2) coupled downlink-uplink…
Analysis of load balancing and interference management in heterogeneous cellular networks
2017
To meet the current cellular capacity demands, proactive offloading is required in heterogeneous cellular networks (HetCNets) comprising of different tiers of base stations (BSs), e.g., small-cell BSs (sBSs) and conventional macro-cell BSs (mBSs). Each tier differs from the others in terms of BS transmit power, spatial density, and association bias. Consequently, the coverage range of each tier BSs is also different from others. Due to low transmit power, a fewer number of users are associated to an sBS as compared with mBS. Thus, inefficient utilization of small-cell resources occurs. To balance the load across the network, it is necessary to push users to the underloaded small cells from …