Sampling Geometric Inhomogeneous Random Graphs in Linear Time

Real-world networks, like social networks or the internet infrastructure, have structural properties such as large clustering coefficients that can best be described in terms of an underlying geometry. This is why the focus of the literature on theoretical models for real-world networks shifted from classic models without geometry, such as Chung-Lu random graphs, to modern geometry-based models, such as hyperbolic random graphs. With this paper we contribute to the theoretical analysis of these modern, more realistic random graph models. Instead of studying directly hyperbolic random graphs, we use a generalization that we call geometric inhomogeneous random graphs (GIRGs). Since we ignore constant factors in the edge probabilities, GIRGs are technically simpler (specifically, we avoid hyperbolic cosines), while preserving the qualitative behaviour of hyperbolic random graphs, and we suggest to replace hyperbolic random graphs by this new model in future theoretical studies. We prove the following fundamental structural and algorithmic results on GIRGs. (1) As our main contribution we provide a sampling algorithm that generates a random graph from our model in expected linear time, improving the best-known sampling algorithm for hyperbolic random graphs by a substantial factor O(n^0.5). (2) We establish that GIRGs have clustering coefficients in {\Omega}(1), (3) we prove that GIRGs have small separators, i.e., it suffices to delete a sublinear number of edges to break the giant component into two large pieces, and (4) we show how to compress GIRGs using an expected linear number of bits.Comment: 25 page

The Web Experiment List: A web service for the recruitment of participants and archiving of Internet-based experiments

TheWeb Experiment List (http://genpsylab-wexlist.unizh.ch/), a free Web-based service for the recruitment of participants in Internet-based experiments, is presented. The Web Experiment List also serves as a searchable archive for the research community. It lists more than 250 links to and descriptions of current and past Web experiments. Searches can be conducted by area of research, language, type of study, date, and status (active vs. archived). Data from log file analyses reveal an increasing use of the Web Experiment List and provide a picture of the distribution of the use of the Web experiment method across disciplines. On a general theoretical note, Web services are discussed as a viable software alternative to the traditional program forma

Towards a Periodic Table of Visualization Methods for Management

In this paper, we describe the effort of defining and compiling existing visualization methods in order to develop a systematic overview based on the logic, look, and use of the periodic table of elements. We first describe the current fragmented state of the visualization field. Then we outline the rules and criteria we applied in conducting our research in order to present a revised periodic table of 100 visualization methods with a proposition how to use it. KEY WORDS knowledge visualization, knowledge visualization methods, periodic table, problem solving, classification, selection framework, visualisation types 1 The Realm of Visualization Methods The discipline of visualization studies is an emergent one and as such represents a so far still highly unstructured domain of research that includes scholars from such distant domains as human-computer interaction, graphic design, management, or architecture. Thus, there are many parallel, unconnected streams and development activities in this field that may move forward without mutually acknowledging or integrating efforts under way elsewhere. In order to contribute to the consolidation of these efforts and to the emergence of a distinct field that achieves cumulative research progress this article proposes an integrative overview on one aspect of the visualization field, namely the development of easily applicable visualization methods, that is to say systematic graphic formats, that can be used to create, share, or codify knowledge (in the sense of insights, experiences, contacts, or skills). In this paper, we present a simple structure, inspired by the use, look, and logic of the periodic table of elements developed in the domain of chemistry. There are numerous benefits that can be achieved through such a structure: First, it can provide a descriptive overview over the domain [1, p. 12] and can function as an inventory or repository like a structured toolbox. In thi

The Web Experiment List: A Web service for the recruitment of participants and archiving of Internet-based experiments

The Web Experiment List (http://genpsylabwexlist.unizh.ch/), a free Web-based service for the recruitment of participants in Internet-based experiments, is presented. The Web Experiment List also serves as a searchable archive for the research community. It lists more than 250 links to and descriptions of current and past Web experiments. Searches can be conducted by area of research, language, type of study, date, and status (active vs. archived). Data from log file analyses reveal an increasing use of the Web Experiment List and provide a picture of the distribution of the use of the Web experiment method across disciplines. On a general theoretical note, Web services are discussed as a viable software alternative to the traditional program format