1,720,956 research outputs found
A Survey of Enabling Technologies for Network Localization, Tracking, and Navigation
No full textLocation information for events, assets, and individuals, mostly focusing on two dimensions so far, has triggered a multitude of applications across different verticals, such as consumer, networking, industrial, health care, public safety, and emergency response use cases. To fully exploit the potential of location awareness and enable new advanced location-based services, localization algorithms need to be combined with complementary technologies including accurate height estimation, i.e., three dimensional location, reliable user mobility classification, and efficient indoor mapping solutions. This survey provides a comprehensive review of such enabling technologies. In particular, we present cellular localization systems including recent results on 5G localization, and solutions based on Wireless Local Area Networks (WLAN), highlighting those that are capable of computing 3D location in multi-floor indoor environments. We overview range-free localization schemes, which have been traditionally explored in Wireless Sensor Networks (WSN) and are nowadays gaining attention for several envisioned Internet of Things (IoT) applications. We also present user mobility estimation techniques, particularly those applicable in cellular networks, that can improve localization and tracking accuracy. Regarding the mapping of physical space inside buildings for aiding tracking and navigation applications, we study recent advances and focus on smartphone-based indoor Simultaneous Localization and Mapping (SLAM) approaches. The survey concludes with service availability and system scalability considerations, as well as security and privacy concerns in location architectures, discusses the technology roadmap, and identifies future research directions.© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Laoudias, Christos, Moreira, Adriano, Kim, Sunwoo, Lee, Sangwoo, Wirola, Lauri, & Fischione, Carlo. (2018). A Survey of Enabling Technologies for Network Localization, Tracking, and Navigation. IEEE Communications Surveys & Tutorials.
http://doi.org/10.1109/COMST.2018.2855063
https://www.ieee.org/publications/rights/rights-policies.htm
Development of a tissue-conducting audio transducer and sensor for mobile use
Full text linkThe ever increasing number of mobile devices with a cellular link as well as services associated with them require innovations in audio technologies. Especially problematic are circumstances, in which high background noise level prohibits communication.
This thesis studies a tissue-conducting device for audio reproduction and recording. The proposed concept is not based on producing or sensing pressure changes in air, but in soft tissues. The device considered is an in-ear actuator and sensor that couples to tympanic canal walls.
A finite element model of ear is developed for simulating the actuator function. The FEmodel includes a novel idea of using a lumped parameter representation for the middle ear bones. The results are compared with respect to the published data and the approach is found valid. The simulations concerning the actuator function show that the mode is unfeasible due to the energy loss in soft tissues. The result is confirmed by subjective tests.
The prototype of the actuator is analyzed with a FE-model. It is observed that the linear FEM cannot account for the observed characteristics in the actuator response. Therefore, a time-domain model accounting for hysteresis is developed. The hysteresis prediction is realized with a rate-independent Preisach model with an addition of a scalar product model for the reversible part of hysteresis. It is shown that the rate-independent Preisach model is not sufficient to predict the response and that a dynamic model is required.
In the sensor mode the device works up to 2.5-3 kHz, after which the recorded signal drops below the noise floor. The finding is supported by the literature. The transfer function between the speech recorded with a microphone and the device is observed to have a decreasing trend. The study leaves open, whether this effect is due to the tissue transfer characteristics, sensor coupling to the tissue or sensor properties. Moreover, a comprehensive discussion on the theory associated with the Finite Element Method is given. Both, structural and piezoelectric FEM are covered
Studies on location technology standards evolution in wireless networks
Full text linkPositioning capability in mobile terminals (phones, laptops, netbooks) is required for various purposes including location-based commercial services, navigation and local search. Other uses include positioning of emergency calls and cellular networks also have internal use for the UE (User Equipment) location information. Moreover, the law and enforcement authorities have needs for positioning terminals and persons carrying them.
A variety of techniques to position a mobile UE is available in the cellular networks. The first category of methods includes utilizing the cellular base station coverage area information and combining that with distance estimates to the base stations. The distance estimates may be based on time delay, time difference or received signal strength measurements. The methods are discussed especially in the context of information they require from the cellular network.
The second category consists of using wireless networks to assist GNSS-based (Global Navigation Satellite System) methods. In the work the physics and prerequisites of the GNSS-based positioning methods are discussed and the significance of the assistance obtainable from the telecommunications networks is highlighted. The assistance is shown to significantly improve time-to-first-fix and sensitivity of the Assisted GNSS receiver.
The study introduces the positioning architectures and protocols in the 3GPP GERAN, UTRAN and E-UTRAN networks known as GSM, 3G and 4G in everyday language, respectively. It is shown that within each network there are dedicated logical and/or physical entities for positioning purposes and their significance to the introduced positioning methods is discussed.
In the discussion emphasis is given on the GERAN control plane positioning protocol called Radio Resource LCS Protocol (LCS for Location Services) also known as RRLP. Especially the GNSS-branch of RRLP is detailed, because its structure has also been copied to UTRAN and also to some extent to the E-UTRAN positioning protocols. It is shown that the generic GNSS structure in RRLP has made it straightforward to add the support for new GNSSs as they emerge. RRLP currently supports GPS in its entirety, GLONASS, QZSS, Galileo and various SBASs. In addition, the location protocol defined for the user plane, OMA SUPL (Open Mobile Alliance Secure User Plane Location protocol), is described and its relation to the 3GPP-defined positioning protocols is discussed.
A plethora of positioning techniques is shown not to be covered in the current wireless positioning standards. Examples include advanced GNSS-based methods, Precise Point Positioning and carrier phase -based relative positioning, which are envisioned to be introduced into the wireless positioning standards in the coming years. It is shown that in order to realize advanced GNSS-based methods in the cellular standards both new assistance data types and protocol features are needed.
Radiomap-based and fingerprint-based methods are also shown not to be covered adequately by the current positioning standards. Introducing the support for these methods is seen as an important milestone towards increasing the availability of the positioning services and solving the indoor positioning challenge. The thesis outlines protocol requirements for these methods as well.
Finally, costs and benefits of the proposed new positioning methods are critically analyzed. Considerations include accuracy, availability and bandwidth aspects. It is found that, in general, accuracy requirements also increase bandwidth consumption. This implies that the development of the new features should be concentrated in the user plane. Hence, OMA SUPL Release 3 together with the extended E-UTRAN positioning protocol are seen as the most promising platforms for introducing new positioning technologies into the wireless positioning standards. Moreover, the outlined standardization roadmap shows that the proposed features are realizable in the near future
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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