15 research outputs found
Clustering Spectrum of scale-free networks
Real-world networks often have power-law degrees and scale-free properties
such as ultra-small distances and ultra-fast information spreading. In this
paper, we study a third universal property: three-point correlations that
suppress the creation of triangles and signal the presence of hierarchy. We
quantify this property in terms of , the probability that two
neighbors of a degree- node are neighbors themselves. We investigate how the
clustering spectrum scales with in the hidden variable
model and show that follows a {\it universal curve} that consists of
three -ranges where remains flat, starts declining, and
eventually settles on a power law with
depending on the power law of the degree distribution. We test these results
against ten contemporary real-world networks and explain analytically why the
universal curve properties only reveal themselves in large networks
Enhancing explainability and scrutability of recommender systems
Our increasing reliance on complex algorithms for recommendations calls for models and methods for explainable, scrutable, and trustworthy AI. While explainability is required for understanding the relationships between model inputs and outputs, a scrutable system allows us to modify its behavior as desired. These properties help bridge the gap between our expectations and the algorithmâs behavior and accordingly boost our trust in AI. Aiming to cope with information overload, recommender systems play a crucial role in ïŹltering content (such as products, news, songs, and movies) and shaping a personalized experience for their users. Consequently, there has been a growing demand from the information consumers to receive proper explanations for their personalized recommendations. These explanations aim at helping users understand why certain items are recommended to them and how their previous inputs to the system relate to the generation of such recommendations. Besides, in the event of receiving undesirable content, explanations could possibly contain valuable information as to how the systemâs behavior can be modiïŹed accordingly. In this thesis, we present our contributions towards explainability and scrutability of recommender systems: âą We introduce a user-centric framework, FAIRY, for discovering and ranking post-hoc explanations for the social feeds generated by black-box platforms. These explanations reveal relationships between usersâ proïŹles and their feed items and are extracted from the local interaction graphs of users. FAIRY employs a learning-to-rank (LTR) method to score candidate explanations based on their relevance and surprisal. âą We propose a method, PRINCE, to facilitate provider-side explainability in graph-based recommender systems that use personalized PageRank at their core. PRINCE explanations are comprehensible for users, because they present subsets of the userâs prior actions responsible for the received recommendations. PRINCE operates in a counterfactual setup and builds on a polynomial-time algorithm for ïŹnding the smallest counterfactual explanations. âą We propose a human-in-the-loop framework, ELIXIR, for enhancing scrutability and subsequently the recommendation models by leveraging user feedback on explanations. ELIXIR enables recommender systems to collect user feedback on pairs of recommendations and explanations. The feedback is incorporated into the model by imposing a soft constraint for learning user-speciïŹc item representations. We evaluate all proposed models and methods with real user studies and demonstrate their beneïŹts at achieving explainability and scrutability in recommender systems.Unsere zunehmende AbhĂ€ngigkeit von komplexen Algorithmen fĂŒr maschinelle Empfehlungen erfordert Modelle und Methoden fĂŒr erklĂ€rbare, nachvollziehbare und vertrauenswĂŒrdige KI. Zum Verstehen der Beziehungen zwischen Modellein- und ausgaben muss KI erklĂ€rbar sein. Möchten wir das Verhalten des Systems hingegen nach unseren Vorstellungen Ă€ndern, muss dessen Entscheidungsprozess nachvollziehbar sein. ErklĂ€rbarkeit und Nachvollziehbarkeit von KI helfen uns dabei, die LĂŒcke zwischen dem von uns erwarteten und dem tatsĂ€chlichen Verhalten der Algorithmen zu schlieĂen und unser Vertrauen in KI-Systeme entsprechend zu stĂ€rken. Um ein ĂbermaĂ an Informationen zu verhindern, spielen Empfehlungsdienste eine entscheidende Rolle um Inhalte (z.B. Produkten, Nachrichten, Musik und Filmen) zu ïŹltern und deren Benutzern eine personalisierte Erfahrung zu bieten. Infolgedessen erheben immer mehr In- formationskonsumenten Anspruch auf angemessene ErklĂ€rungen fĂŒr deren personalisierte Empfehlungen. Diese ErklĂ€rungen sollen den Benutzern helfen zu verstehen, warum ihnen bestimmte Dinge empfohlen wurden und wie sich ihre frĂŒheren Eingaben in das System auf die Generierung solcher Empfehlungen auswirken. AuĂerdem können ErklĂ€rungen fĂŒr den Fall, dass unerwĂŒnschte Inhalte empfohlen werden, wertvolle Informationen darĂŒber enthalten, wie das Verhalten des Systems entsprechend geĂ€ndert werden kann. In dieser Dissertation stellen wir unsere BeitrĂ€ge zu ErklĂ€rbarkeit und Nachvollziehbarkeit von Empfehlungsdiensten vor. âą Mit FAIRY stellen wir ein benutzerzentriertes Framework vor, mit dem post-hoc ErklĂ€rungen fĂŒr die von Black-Box-Plattformen generierten sozialen Feeds entdeckt und bewertet werden können. Diese ErklĂ€rungen zeigen Beziehungen zwischen BenutzerproïŹlen und deren Feeds auf und werden aus den lokalen Interaktionsgraphen der Benutzer extrahiert. FAIRY verwendet eine LTR-Methode (Learning-to-Rank), um die ErklĂ€rungen anhand ihrer Relevanz und ihres Grads unerwarteter Empfehlungen zu bewerten. âą Mit der PRINCE-Methode erleichtern wir das anbieterseitige Generieren von ErklĂ€rungen fĂŒr PageRank-basierte Empfehlungsdienste. PRINCE-ErklĂ€rungen sind fĂŒr Benutzer verstĂ€ndlich, da sie Teilmengen frĂŒherer Nutzerinteraktionen darstellen, die fĂŒr die erhaltenen Empfehlungen verantwortlich sind. PRINCE-ErklĂ€rungen sind somit kausaler Natur und werden von einem Algorithmus mit polynomieller Laufzeit erzeugt , um prĂ€zise ErklĂ€rungen zu ïŹnden. âą Wir prĂ€sentieren ein Human-in-the-Loop-Framework, ELIXIR, um die Nachvollziehbarkeit der Empfehlungsmodelle und die QualitĂ€t der Empfehlungen zu verbessern. Mit ELIXIR können Empfehlungsdienste Benutzerfeedback zu Empfehlungen und ErklĂ€rungen sammeln. Das Feedback wird in das Modell einbezogen, indem benutzerspeziïŹscher Einbettungen von Objekten gelernt werden. Wir evaluieren alle Modelle und Methoden in Benutzerstudien und demonstrieren ihren Nutzen hinsichtlich ErklĂ€rbarkeit und Nachvollziehbarkeit von Empfehlungsdiensten
Algorithms and models for the Web graph : 12th international workshop, WAW 2015, Eindhoven, The Netherlands, December 10-11, 2015 : proceedings
This volume contains the papers presented at WAW2015, the 12th Workshop on Algorithms and Models for the Web-Graph held during December 10â11, 2015, in Eindhoven. There were 24 submissions. Each submission was reviewed by at least one, and on average two, Program Committee members. The committee decided to accept 15 papers. The program also included three invited talks, by Mariana Olvera-Cravioto (Columbia University), Remco van der Hofstad (Eindhoven University of Technology), and Paul Van Dooren (Catholic University of Louvain). This year the workshop was accompanied by a school aimed at PhD students, postdocs, and young researchers. The speakers of the school were Dean Eckles (Facebook), David F. Gleich, Kyle Kloster (Purdue University), and Tobias MĂŒller (Utrecht University). Analyzing data as graphs has transitioned from a minor subfield into a major industrial effort over the past 20 years. The World Wide Web was responsible for much of this growth and the Workshop on Algorithms and Models for the Web-Graph (WAW) originally started by trying to understand the behavior and processes underlying the Web. It has since outgrown these roots and WAW is now one of the premier venues for original research work that blends rigorous theory and experiments in analyzing data as a graph. We believe that the 12th WAW continues the high standards of the earlier workshops and as a result maintains the tradition of a small, high-quality workshop. The organizers would like to thank EURANDOM, the NETWORKS grant, Microsoft Research, and Google for contributing to the financial aspect of the workshop. We would especially like to thank EURANDOM and the Eindhoven University of Technology for their hospitality and smooth organization of the material aspects of the conference such as drinks/food, accommodation for speakers, etc. The editorial aspects of the proceedings were supported via the online tool EasyChair. It made our work easier and smoother
Fundamental Approaches to Software Engineering
This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications
Fundamental Approaches to Software Engineering
This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications