1,720,996 research outputs found
One-Tier versus Two-Tier Wireless Sensor Networks: Coverage Problem
Full text linkThis paper tackles the coverage problem in homogenous and heterogeneous wireless sensor networks. The homogenous sensor network consists of sensor nodes and relays; however, the heterogeneous sensor network consists of sensor nodes, super nodes, and satellite nodes. In the latter network, super nodes and satellite nodes are utilized to demonstrate different scenarios. Super nodes consume huge amount of energy, compared to sensor nodes. To address this problem, the aim of this paper is to find the baseline when super nodes are used efficiently, despite the inherited high power consumption. Wolfram Mathematica is used to compare random independent deployment circular analytical model against a much simpler square analytical model. The achieved results showed that the simple square model is very close to circular model when K -coverage is ≤2
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
An Enhanced Energy Saving Approach for WSNs
No full textAbstractWireless sensor networks are used today in a wide range of applications, all of which employ a large number of sensors. In large scale sensor networks, sensor nodes are often not easily accessible. Because of this, the energy consumption of wireless networks is an important matter as well as a popular topic of research. A sensor node consumes energy while collecting, processing, transmitting and receiving data. Each of these processes could be the focus of research, so there are many investigations into these subjects, centering on ways of reducing energy consumption and extending the lifetimes of networks.In this paper we study data processing schemes that define the distribution of decision making, which affects system accuracy and energy consumption. The two typical detection schemes are the centralized and distributed schemes. In a centralized scheme, nodes collect samples from the environment and send them to a “fusion center”, where the samples are used to arrive at a final decision. This scheme provides optimal decision accuracy; however, it consumes considerable energy. In contrast, distributed schemes allow nodes to make local 1-bit decisions, which are sent to the fusion center to make the final decision. In a hybrid scheme the network specifies the level of accuracy required for the whole system. This can be achieved by manipulating the scheme to work sometimes as centralized other times as distributed. We propose an energy-saving hybrid scheme that focuses on optimizing transmission energy, since most of the energy consumed is in the transmission process. In the proposed scheme each node alternates between centralized and distributed according to its location and path length. Nodes with longer path lengths are classified as acting more as distributed than those with shorter path lengths
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
Novel Energy-Aware 3D UAV Path Planning and Collision Avoidance Using Receding Horizon and Optimization-Based Control
No full textUnmanned Aerial Vehicles (UAVs) have gained significant popularity in recent years thanks to their agility, mobility, and cost-effectiveness. However, UAV navigation presents several challenges, particularly in path planning, which requires determining an optimal route while avoiding obstacles and adhering to various constraints. Another critical challenge is the limited flight time imposed by the onboard battery. This paper introduces a novel approach for energy-efficient three-dimensional online path planning for UAV formations operating in complex environments. We formulate the path planning problem as a minimization optimization problem, and employ Mixed-Integer Linear Programming (MILP) to achieve optimal solutions. The cost function is designed to minimize energy consumption while considering the inter-collision and intra-collision avoidance constraints within a limited detection range. To achieve this, an optimization approach incorporating Receding Horizon Control (RHC) is applied. The entire path is divided into segments or sub-paths, with constraints used to avoid collisions with obstacles and other members of the fleet. The proposed optimization approach enables fast navigation through dense environments and ensures a collision-free path for all UAVs. A path-smoothing strategy is proposed to further reduce energy consumption caused by sharp turns. The results demonstrate the effectiveness and accuracy of the proposed approach in dense environments with high risk of collision. We compared our proposed approach against recent works, and the results illustrate that the proposed approach outperforms others in terms of UAV formation, number of collisions, and partial path generation time
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