Recent research has shown a substantial active presence of bots in online social networks (OSNs). In this paper we utilise our previous work (Stweeler) to comparatively analyse the usage and impact of bots and humans on Twitter, one of the largest OSNs in the world. We collect a large-scale Twitter dataset and define various metrics based on tweet metadata. Using a human annotation task we assign 'bot' and 'human' ground-truth labels to the dataset, and compare the annotations against an online bot detection tool for evaluation. We then ask a series of questions to discern important behavioural characteristics of bots and humans using metrics within and among four popularity groups. From the comparative analysis we draw differences and interesting similarities between the two entities, thus paving the way for reliable classification of bots, and studying automated political infiltration and advertisement campaigns.
This paper addresses web interfaces for High Performance Computing (HPC) simulation software. First, it presents a brief history, starting in the 90s with Java applets, of web interfaces used for accessing and making best possible use of remote HPC resources. Then this article reviews the present state of such HPC web-based portals. We identify and discuss the key features and constraints that characterize HPC portals. The design and development of Bull extreme factory Computing Studio v3 (XCS3) is chosen as a common thread for showing how these features can all be implemented in one software: multi-tenancy, multi-scheduler compatibility, HPC application template framework, complete control through an HTTP RESTful API, customizable user interface with Responsive Web Design, remote visualization, Role Base Access Control, and access through the Authentication, Authorization, and Accounting proven security framework. The paper concludes with the benefits of using such an HPC portal for both end-users and IT administrators.
Social network research has begun to take advantage of fine-grained communications regarding coordination, decision-making, and knowledge sharing. These studies, however, have not generally analyzed how external events are associated with a social network's structure and communicative properties. Here, we study how external events are associated with a network's change in structure and communications. Analyzing a complete dataset of millions of instant messages among the decision-makers with different roles in a large hedge fund and their network of outside contacts, we investigate the link between price shocks, network structure, and change in the affect and cognition of decision-makers embedded in the network. We also analyze the communication dynamics of among specialized teams in the organization. When price shocks occur the communication network tends not to display structural changes associated with adaptiveness. Rather, the network ``turtles up". It displays a propensity for higher clustering, strong tie interaction, and an intensification of insider vs. outsider and and within-role vs. between-role communication. Further, we find changes in network structure predict shifts in cognitive and affective processes, execution of new transactions, and local optimality of transactions better than prices, revealing the important predictive relationship between network structure and collective behavior within a social network.