scholarly journals MODELING TEMPORAL AND SPATIAL FEATURES OF COLLABORATION NETWORK

2007 ◽  
Vol 18 (07) ◽  
pp. 1157-1172 ◽  
Author(s):  
ANJAN KUMAR CHANDRA ◽  
KAMALIKA BASU HAJRA ◽  
PRATAP KUMAR DAS ◽  
PARONGAMA SEN
Keyword(s):  
Social Network ◽  
Time Evolution ◽  
Spatial Dependence ◽  
Real Data ◽  
Physical Review ◽  
Collaboration Network ◽  
Link Length ◽  
Spatial Features ◽  
Temporal And Spatial ◽  
Clustering Coefficients

The collaboration network is an example of a social network which has both non-trivial temporal and spatial dependence. Based on the observations of collaborations in Physical Review Letters, a model of collaboration network is proposed which correctly reproduces the time evolution of the link length distributions, clustering coefficients, degree distributions, and assortative property of real data to a large extent.

scholarly journals The role of action effects in motor sequence planning and execution: exploring the influence of temporal and spatial effect anticipation

2021 ◽  
Author(s):  
Rachel M. Brown ◽  
Erik Friedgen ◽  
Iring Koch
Keyword(s):  
Action Planning ◽  
Spatial Effects ◽  
Motor Sequence ◽  
Action Sequence ◽  
Sequential Action ◽  
Spatial Features ◽  
Temporal Features ◽  
Action Sequences ◽  
Temporal And Spatial ◽  
Anticipation Effect

AbstractActions we perform every day generate perceivable outcomes with both spatial and temporal features. According to the ideomotor principle, we plan our actions by anticipating the outcomes, but this principle does not directly address how sequential movements are influenced by different outcomes. We examined how sequential action planning is influenced by the anticipation of temporal and spatial features of action outcomes. We further explored the influence of action sequence switching. Participants performed cued sequences of button presses that generated visual effects which were either spatially compatible or incompatible with the sequences, and the spatial effects appeared after a short or long delay. The sequence cues switched or repeated across trials, and the predictability of action sequence switches was varied across groups. The results showed a delay-anticipation effect for sequential action, whereby a shorter anticipated delay between action sequences and their outcomes speeded initiation and execution of the cued action sequences. Delay anticipation was increased by predictable action switching, but it was not strongly modified by the spatial compatibility of the action outcomes. The results extend previous demonstrations of delay anticipation to the context of sequential action. The temporal delay between actions and their outcomes appears to be retrieved for sequential planning and influences both the initiation and the execution of actions.

scholarly journals Scientific collaboration network ammong Brazilian universities

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Maria Isabel Escalona-Fernandez ◽  
Antonio Pulgarin-Guerrero ◽  
Ely Francina Tannuri de Oliveira ◽  
Maria Cláudia Cabrini Gracio
Keyword(s):  
Social Network ◽  
Social Network Analysis ◽  
Network Analysis ◽  
Scientific Collaboration ◽  
Methodological Approach ◽  
Scientific Production ◽  
Collaboration Network ◽  
Network Data ◽  
New Knowledge

This paper analyses the scientific collaboration network formed by the Brazilian universities that investigate in dentistry area. The constructed network is based on the published documents in the Scopus (Elsevier) database covering a period of 10 (ten) years. It is used social network analysis as the best methodological approach to visualize the capacity for collaboration, dissemination and transmission of new knowledge among universities. Cohesion and density of the collaboration network is analyzed, as well as the centrality of the universities as key-actors and the occurrence of subgroups within the network. Data were analyzed using the software UCINET and NetDraw. The number of documents published by each university was used as an indicator of its scientific production.

Temporal and spatial dependence of hydrodynamic correlations: Simulation and experiment

1995 ◽  
Vol 52 (6) ◽  
pp. 6550-6572 ◽  
Author(s):  
Anthony J. C. Ladd ◽  
Hu Gang ◽  
J. X. Zhu ◽  
D. A. Weitz
Keyword(s):  
Spatial Dependence ◽  
Simulation And Experiment ◽  
Temporal And Spatial

Spreading Activation Connectivity Based Approach to Network Clustering

2018 ◽  
pp. 207-219
Author(s):  
Alexander Troussov ◽  
Sergey Maruev ◽  
Sergey Vinogradov ◽  
Mikhail Zhizhin
Keyword(s):  
Big Data ◽  
Social Network ◽  
Social Systems ◽  
Network Models ◽  
Real Data ◽  
Spreading Activation ◽  
Network Clustering ◽  
Clustering Method ◽  
Network Characteristics ◽  
Structure Detection

Techno-social systems generate data, which are rather different, than data, traditionally studied in social network analysis and other fields. In massive social networks agents simultaneously participate in several contexts, in different communities. Network models of many real data from techno-social systems reflect various dimensionalities and rationales of actor's actions and interactions. The data are inherently multidimensional, where “everything is deeply intertwingled”. The multidimensional nature of Big Data and the emergence of typical network characteristics in Big Data, makes it reasonable to address the challenges of structure detection in network models, including a) development of novel methods for local overlapping clustering with outliers, b) with near linear performance, c) preferably combined with the computation of the structural importance of nodes. In this chapter the spreading connectivity based clustering method is introduced. The viability of the approach and its advantages are demonstrated on the data from the largest European social network VK.

Improving Collaborative Filtering Algorithms

2020 ◽  
pp. 638-657
Author(s):  
Firas Ben Kharrat ◽  
Aymen Elkhleifi ◽  
Rim Faiz
Keyword(s):  
Social Network ◽  
Web Sites ◽  
Opinion Mining ◽  
Semantic Analysis ◽  
Real Data ◽  
Data Sets ◽  
Suggested Approach ◽  
Opinion Score ◽  
Positive Results ◽  
Cold Start Problem

This paper puts forward a new recommendation algorithm based on semantic analysis as well as new measurements. Like Facebook, Social network is considered as one of the most well-prominent Web 2.0 applications and relevant services elaborating into functional ways for sharing opinions. Thereupon, social network web sites have since become valuable data sources for opinion mining. This paper proposes to introduce an external resource a sentiment from comments posted by users in order to anticipate recommendation and also to lessen the cold-start problem. The originality of the suggested approach means that posts are not merely characterized by an opinion score, but receive an opinion grade notion in the post instead. In general, the authors' approach has been implemented with Java and Lenskit framework. The study resulted in two real data sets, namely MovieLens and TripAdvisor, in which the authors have shown positive results. They compared their algorithm to SVD and Slope One algorithms. They have fulfilled an amelioration of 10% in precision and recall along with an improvement of 12% in RMSE and nDCG.

Forecasting Socioeconomic Distributions on Small-Area Spatial Domains for Count Data

2020 ◽  
pp. 240-263
Author(s):  
Rosa Bernardini Papalia ◽  
Esteban Fernandez-Vazquez
Keyword(s):  
Spatial Heterogeneity ◽  
Spatial Data ◽  
Spatial Dependence ◽  
Small Area ◽  
Real Data ◽  
Spatial Domains ◽  
Technical Issues ◽  
Level Of Aggregation ◽  
Socioeconomic Data ◽  
Available Information

Statistical information for empirical analysis is frequently available at a higher level of aggregation than is desired. The spatial disaggregation of the socioeconomic data is considered complex due to the inherent spatial properties and relationships of the spatial data, namely, spatial dependence and spatial heterogeneity. The spatial dependence, spatial heterogeneity, and effect of scale produce major technical issues that largely impact the accuracy of the regional forecast disaggregation. In this chapter, we propose entropy-based spatial forecast disaggregation methods for count areal data that use all available information at each level of aggregation even if it is incomplete. The proposed methods are validated through Monte Carlo simulations using ancillary information. An empirical application to real data is also presented.

Improving Collaborative Filtering Algorithms

2016 ◽  
Vol 7 (3) ◽  
pp. 99-118 ◽  
Author(s):  
Firas Ben Kharrat ◽  
Aymen Elkhleifi ◽  
Rim Faiz
Keyword(s):  
Social Network ◽  
Web Sites ◽  
Opinion Mining ◽  
Semantic Analysis ◽  
Real Data ◽  
Data Sets ◽  
Recommendation Algorithm ◽  
Suggested Approach ◽  
Opinion Score ◽  
Positive Results

This paper puts forward a new recommendation algorithm based on semantic analysis as well as new measurements. Like Facebook, Social network is considered as one of the most well-prominent Web 2.0 applications and relevant services elaborating into functional ways for sharing opinions. Thereupon, social network web sites have since become valuable data sources for opinion mining. This paper proposes to introduce an external resource a sentiment from comments posted by users in order to anticipate recommendation and also to lessen the cold-start problem. The originality of the suggested approach means that posts are not merely characterized by an opinion score, but receive an opinion grade notion in the post instead. In general, the authors' approach has been implemented with Java and Lenskit framework. The study resulted in two real data sets, namely MovieLens and TripAdvisor, in which the authors have shown positive results. They compared their algorithm to SVD and Slope One algorithms. They have fulfilled an amelioration of 10% in precision and recall along with an improvement of 12% in RMSE and nDCG.

scholarly journals Dynamic response of microglia/macrophage polarization following demyelination in mice

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Tianci Chu ◽  
Yi Ping Zhang ◽  
Zhisen Tian ◽  
Chuyuan Ye ◽  
Mingming Zhu ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Macrophage Polarization ◽  
Functional Decline ◽  
Oligodendrocyte Progenitor Cells ◽  
Spatial Features ◽  
Lesion Pattern ◽  
Temporal Features ◽  
Temporal And Spatial ◽  
Highly Correlated ◽  
Focal Demyelination

Abstract Background The glial response in multiple sclerosis (MS), especially for recruitment and differentiation of oligodendrocyte progenitor cells (OPCs), predicts the success of remyelination of MS plaques and return of function. As a central player in neuroinflammation, activation and polarization of microglia/macrophages (M/M) that modulate the inflammatory niche and cytokine components in demyelination lesions may impact the OPC response and progression of demyelination and remyelination. However, the dynamic behaviors of M/M and OPCs during demyelination and spontaneous remyelination are poorly understood, and the complex role of neuroinflammation in the demyelination-remyelination process is not well known. In this study, we utilized two focal demyelination models with different dynamic patterns of M/M to investigate the correlation between M/M polarization and the demyelination-remyelination process. Methods The temporal and spatial features of M/M activation/polarization and OPC response in two focal demyelination models induced by lysolecithin (LPC) and lipopolysaccharide (LPS) were examined in mice. Detailed discrimination of morphology, sensorimotor function, diffusion tensor imaging (DTI), inflammation-relevant cytokines, and glial responses between these two models were analyzed at different phases. Results The results show that LPC and LPS induced distinctive temporal and spatial lesion patterns. LPS produced diffuse demyelination lesions, with a delayed peak of demyelination and functional decline compared to LPC. Oligodendrocytes, astrocytes, and M/M were scattered throughout the LPS-induced demyelination lesions but were distributed in a layer-like pattern throughout the LPC-induced lesion. The specific M/M polarization was tightly correlated to the lesion pattern associated with balance beam function. Conclusions This study elaborated on the spatial and temporal features of neuroinflammation mediators and glial response during the demyelination-remyelination processes in two focal demyelination models. Specific M/M polarization is highly correlated to the demyelination-remyelination process probably via modulations of the inflammatory niche, cytokine components, and OPC response. These findings not only provide a basis for understanding the complex and dynamic glial phenotypes and behaviors but also reveal potential targets to promote/inhibit certain M/M phenotypes at the appropriate time for efficient remyelination.

Research Activities and Networks in CAIS Conferences for the Period of 1993- 2015: Social Network Analysis

1969 ◽  
Author(s):  
Kwan Yi ◽  
Tao Jin ◽  
Ping Li
Keyword(s):  
Social Network ◽  
Social Network Analysis ◽  
Network Analysis ◽  
Collaborative Research ◽  
Information Science ◽  
Research Collaboration ◽  
Collaboration Network ◽  
Research Activities ◽  
Canadian Association ◽  
Collaborative Activities

Since 1973 the Canadian Association for Information Science (CAIS/ACSI) has consecutively held 43 annual conferences. The purpose of this study is to better understand the research and collaborative activities in the community of CAIS conferences, based on a social network analysis (SNA) approach. A total of 827 papers from 778 authors have been presented in CAIS for the period of 1993 to 2015, in association with 209 different organizations and 25 countries. A component analysis that has been applied to the collaboration network has discovered research collaboration patterns. This study contributes to discovering collaborative research activities and formation through the CAIS conference and to the literature of the scientific collaboration in the LIS field. Depuis 1973, l'Association canadienne de sciences de l'information (ACSI/CAIS) a tenu 43 congrès annuels consécutifs. Le but de cette étude est de mieux comprendre les activités de recherche et de collaboration dans la communauté de l’ACSI, à l’aide d’une approche d’analyse des réseaux sociaux (ARS). Un total de 827 articles de 778 auteurs ont été présentés à l’ACSI dans la période 1993-2015, en association avec 209 organisations différentes et 25 pays. L’analyse des composantes du réseau de collaboration met en lumière l’existence de patrons de collaboration de recherche au sein de la communauté. Cette étude contribue à l’étude des activités  de collaboration au sein des congrès de l’ACSI ainsi qu’à la littérature sur la collaboration scientifique dans le domaine BSI.

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