On Modeling Heterogeneous Wireless Networks Using Non-Poisson Point Processes

Future wireless networks are required to support 1000 times higher data rate, than the current LTE standard. In order to meet the ever increasing demand, it is inevitable that, future wireless networks will have to develop seamless interconnection between multiple technologies. A manifestation of this idea is the collaboration among different types of network tiers such as macro and small cells, leading to the so-called heterogeneous networks (HetNets). Researchers have used stochastic geometry to analyze such networks and understand their real potential. Unsurprisingly, it has been revealed that interference has a detrimental effect on performance, especially if not modeled properly. Interference can be correlated in space and/or time, which has been overlooked in the past. For instance, it is normally assumed that the nodes are located completely independent of each other and follow a homogeneous Poisson point process (PPP), which is not necessarily true in real networks since the node locations are spatially dependent. In addition, the interference correlation created by correlated stochastic processes has mostly been ignored. To this end, we take a different approach in modeling the interference where we use non-PPP, as well as we study the impact of spatial and temporal correlation on the performance of HetNets. To illustrate the impact of correlation on performance, we consider three case studies from real-life scenarios. Specifically, we use massive multiple-input multiple-output (MIMO) to understand the impact of spatial correlation; we use the random medium access protocol to examine the temporal correlation; and we use cooperative relay networks to illustrate the spatial-temporal correlation. We present several numerical examples through which we demonstrate the impact of various correlation types on the performance of HetNets.Comment: Submitted to IEEE Communications Magazin

El impacto de las publicaciones seriadas y su efecto sobre la producción científica cubana sobre Bibliotecología y Ciencias +de la Información

Objective.The aim of this study was to identify, from a quantitative perspective, differences between Cuban scientific research published in high visible journals and the rest of the national scientific production, using as analytical tools the quartiles of visibility established by the Scimago Journal & Country Rank,compiled from Scopus database. Method.As a case study, Cuban scientific output on Library and Information Sciences indexed by this database was selected. A battery of scientometric indicators was used to analyze levels of citation, collaboration and leadership involved in articles published by journals belonging to each of the visibility quartiles. Correlation between the studied indicators was analyzed. Results/Discussion.High dependence of the indicators based on citation analysis was confirmed, as well as correlation between international collaboration and journal quartiles of visibility. Conclusions.It is concluded that the national scientific output with the greatest influence on the international scientific community in this domain is mainly published by journals belonging to the first quartile of visibility. Likewise, it was identified that national scientific output on Library and Information Sciences depends on international collaboration to reach high levels of visibility, and still is not capable of systematically generate research with a significant impact on the international scientific community. Originality/Value.First bibliometric study of Cuban Library and Information Sciences using the impact of journals where research where published as main analytical category

Effects of Scientific Collaboration between Domestic and Foreign Authors on Quality Indices of Journals

The aim of the study was to determine the effect of scientific collaboration between domestic (Iranian) and foreign authors on their quality indices in articles published in Iranian medical journals, indexed in the Web of Science citation database. The present scientometric study was conducted on the 22 Iranian medical journals that indexed in Web of Science from 2010 to 2016. Using stratified systematic random sampling method and Cochran formula, the sample size was determined 1230 articles. The data analysis was performed by Microsoft Excel and descriptive methods. The qualitative indices were determined using the Klimogrof-Smirnov test, Kruskal-Wallis test and correlation coefficient. The results revealed that 4.66 percent of the articles were compiled by Iranian authors, 29 percent written by foreign authors and 6.4 percent was written by scientific collaboration between Iranian and foreign authors. The average number of authors for each article was 4.9. The journals that have articles which have Iranian authors have a lower Impact Factor (0.69%) than the journal's articles which is the product of the collaboration of Iranian and foreign authors (0.82%). In conclusion, international collaboration in the writing of articles has a direct effect on qualitative indexes of articles, including Impact Factor, 5-years Impact Factor, Immediacy index and journal's Impact Factor

Studying the Emerging Global Brain: Analyzing and Visualizing the Impact of Co-Authorship Teams

This paper introduces a suite of approaches and measures to study the impact of co-authorship teams based on the number of publications and their citations on a local and global scale. In particular, we present a novel weighted graph representation that encodes coupled author-paper networks as a weighted co-authorship graph. This weighted graph representation is applied to a dataset that captures the emergence of a new field of science and comprises 614 papers published by 1,036 unique authors between 1974 and 2004. In order to characterize the properties and evolution of this field we first use four different measures of centrality to identify the impact of authors. A global statistical analysis is performed to characterize the distribution of paper production and paper citations and its correlation with the co-authorship team size. The size of co-authorship clusters over time is examined. Finally, a novel local, author-centered measure based on entropy is applied to determine the global evolution of the field and the identification of the contribution of a single author's impact across all of its co-authorship relations. A visualization of the growth of the weighted co-author network and the results obtained from the statistical analysis indicate a drift towards a more cooperative, global collaboration process as the main drive in the production of scientific knowledge.Comment: 13 pages, 9 figure

Activity Index (AI) and extent of collaboration: a case study of rainwater harvesting literature with a scientometric overview

Rainwater harvesting research is being conducted in much wider perspectives from agriculture to using in house toilets. The study has assessed the research activity by different countries with the help of Activity Index (AI) and the collaboration and its impact. The SCOPUS publication records are made use of for the analysis of RWH research activities. The quality of the publications is analysed in terms of citations received to the papers and Spain has come on the top having 42 citations per paper. Cross-field relative activity in rainwater harvesting research is measured and it was interesting to note that among the leading countries conducting RWH research, a few developed countries are below world average of RWH activity. Out of the 141 countries which have at least one publication on RWH, 132 (94%) have at least one paper written in collaboration with other countries. US is the collaboration hub of many countries and the strength of collaboration of India, China, UK, Brazil is noteworthy. It was also found that there is a positive correlation between the collaboration strength and impact of papers. The results are relevant to know the relative of strength of different countries in RWH as well as boosting the collaboration among countries and researcher mobility

A study of physician collaborations through social network and exponential random graph

Background: Physician collaboration, which evolves among physicians during the course of providing healthcare services to hospitalised patients, has been seen crucial to effective patient outcomes in healthcare organisations and hospitals. This study aims to explore physician collaborations using measures of social network analysis (SNA) and exponential random graph (ERG) model. Methods. Based on the underlying assumption that collaborations evolve among physicians when they visit a common hospitalised patient, this study first proposes an approach to map collaboration network among physicians from the details of their visits to patients. This paper terms this network as physician collaboration network (PCN). Second, SNA measures of degree centralisation, betweenness centralisation and density are used to examine the impact of SNA measures on hospitalisation cost and readmission rate. As a control variable, the impact of patient age on the relation between network measures (i.e. degree centralisation, betweenness centralisation and density) and hospital outcome variables (i.e. hospitalisation cost and readmission rate) are also explored. Finally, ERG models are developed to identify micro-level structural properties of (i) high-cost versus low-cost PCN; and (ii) high-readmission rate versus low-readmission rate PCN. An electronic health insurance claim dataset of a very large Australian health insurance organisation is utilised to construct and explore PCN in this study. Results: It is revealed that the density of PCN is positively correlated with hospitalisation cost and readmission rate. In contrast, betweenness centralisation is found negatively correlated with hospitalisation cost and readmission rate. Degree centralisation shows a negative correlation with readmission rate, but does not show any correlation with hospitalisation cost. Patient age does not have any impact for the relation of SNA measures with hospitalisation cost and hospital readmission rate. The 2-star parameter of ERG model has significant impact on hospitalisation cost. Furthermore, it is found that alternative-k-star and alternative-k-two-path parameters of ERG model have impact on readmission rate. Conclusions: Collaboration structures among physicians affect hospitalisation cost and hospital readmission rate. The implications of the findings of this study in terms of their potentiality in developing guidelines to improve the performance of collaborative environments among healthcare professionals within healthcare organisations are discussed in this paper. © 2013 Uddin et al.; licensee BioMed Central Ltd.published_or_final_versio

Evaluation of Rural E-Learning Strategy on Organization Performance: Case of Intel’s Rusinga Technology Classroom, Kenya.

E-learning is a creative innovation of learning and is emerging as a credible alternative to traditional educational delivery techniques because it saves on organizations’ training costs and travel time, enables organizations to become increasingly more market-oriented and competitive, it facilitates better training and attracts more students thereby generating diversified revenue streams. Intel’s Rusinga technology classroom is a solar powered mobile computer lab which provides an interactive e-learning program to learners in Rusinga Island, Kenya. The selection of this technology classroom was done based on the learners’ preference to it rather than the conventional modes after a preliminary survey. The entire study was carried out between February 2014 and May 2014. The main objective of the study was to evaluate rural e-learning strategy on the performance of Intel’s Rusinga technology classroom. The quantitative method approach was used in handling this research problem. The research techniques used to collect data were questionnaires to teachers. Data was collected from 10th April to 24th April 2014 in Rusinga Island. Data analysis was conducted using Statistical Package for Social Sciences version 17, which was used to generate cross-tabulation in order to demonstrate the combined distributions of variables in a contingency table in matrix format.  The findings of this study were analyzed quantitatively. Quantitative data analysis was used to extract descriptive and inferential statistic where as chi-square test and correlation coefficient were used to test the hypotheses. The findings of the study are as follows; Resourcing/financing indicated a positive impact on performance indices with P values less than 0.05 and positive correlation coefficients, indicating the positive impact on organization performance, Collaboration/outsourcing indicated a positive impact on performance indices with P values less than 0.05 and positive correlation coefficients, indicating the positive impact on organization performance and selecting technology indicated a positive impact on performance indices with P values less than 0.05 and positive correlation coefficients, indicating the positive impact on organization performance. This evaluation showed that resourcing/financing, collaboration/outsourcing and selecting technology have an effect on the performance of organizations. It is therefore important that these factors are considered appropriately in the investment of e-learning in organizations

Research Productivity on Manuscripts in the field of Social Science (2010-2020). Scopus Database

The study aimed to assess and analyze the research productivity on manuscripts in the field of social science on a set of quantitative and qualitative metrics to discover underlying research trends at global, national, organizational and individual level. The study is based on 11 years’ global research data (N=1136) on the topic sourced from Scopus database for the time span 2010-2020. The scientometric analysis used to assess the research productivity. The research productivity on manuscripts registered 17.21 per cent annual average growth and 6.36 per cent compound annual growth rate with an average citation impact of 1.42 citations per paper. The average number of authors per paper was 1.29 and the average productivity per author was 0.79. The resultant data indicates that the degree of collaboration ranges between 0.13≥0.24 and the overall degree of collaboration was 0.17. The Pearson correlation analysis inferred a significant and positive relationship (r = 0.889, N = 11, p =0.000) between number of articles and the number of authors

The Benefits of Parent-Teacher Collaboration on Achievement in the Preschool Classroom

This action research project was conducted to identify a correlation between parent-teacher collaboration and student achievement in the preschool classroom. Baseline data was gathered from the preschool student’s using fall Individual Development and Growth Indicators (IDGI) benchmark scores. Opportunities for parent-teacher collaboration began with monthly newsletters sent out on the classroom webpage, parent-teacher conferences, and signed homework assignments. Parent-teacher engagement was tracked through a tally system. A spreadsheet kept track of the number of communications that parents engaged in, as well as the type of communication. All students were progress monitored within each two week session using the IDGI’s progress monitoring screener. The winter IDGI benchmark scores were then used to gather ending data. Achievement was measured by comparing fall and winter data with the amount of parent engagement to determine whether or not parent-teacher collaboration has a direct impact on student learning. Data was also collected tracking the type of communication parents engaged in. The total number of each type of engagement was tallied and used to determine the most effective method for engaging families