Lower bounds on systolic gossip

AbstractGossiping is an extensively investigated information dissemination process in which each processor has a distinct item of information and has to collect all the items possessed by the other processors. In this paper we provide an innovative and general lower bound technique relying on the novel notion of delay digraph of a gossiping protocol and on the use of matrix norm methods. Such a technique is very powerful and allows the determination of new and significantly improved lower bounds in many cases. In fact, we derive the first general lower bound on the gossiping time of systolic protocols, i.e., constituted by a periodic repetition of simple communication steps. In particular, given any network of n processors and any systolic period s, in the directed and the undirected half-duplex cases every s-systolic gossip protocol takes at least log(n)/log(1/λ)−O(loglog(n)) time steps, where λ is the unique solution between 0 and 1 of λ·p⌊s/2⌋(λ)·p⌈s/2⌉(λ)=1, with pi(λ)=1+λ2+⋯+λ2i−2 for any integer i>0. We then provide improved lower bounds in the directed and half-duplex cases for many well-known network topologies, such as Butterfly, de Bruijn, and Kautz graphs. All the results are extended also to the full-duplex case. Our technique is very general, as for s→∞ it allows the determination of improved results even for non-systolic protocols. In fact, for general networks, as a simple corollary it yields a lower bound only an O(loglog(n)) additive factor far from the general one independently proved in [Proc. 1st ACM Symposium on Parallel Algorithms and Architectures (SPAA), 1989, p. 318; Topics in Combinatorics and Graph Theory (1990) 451; SIAM Journal on Computing 21(1) (1992) 111; Discrete Applied Mathematics 42 (1993) 75] for all graphs and any (non-systolic) gossip protocol. Moreover, for specific networks, it significantly improves with respect to the previously known results, even in the full-duplex case. Correspondingly, better lower bounds on the gossiping time of non-systolic protocols are determined in the directed, half-duplex and full-duplex cases for Butterfly, de Bruijn, and Kautz graphs. Even if in this paper we give only a limited number of examples, our technique has wide applicability and gives a general framework that often allows to get improved lower bounds on the gossiping time of systolic and non-systolic protocols in the directed, half-duplex and full-duplex cases

Effective Systolic Algorithms for Gossiping in Cycles and Two-Dimensional Grids (Extended Abstract)

) Juraj Hromkovic 1;?? , Ralf Klasing 2 , Dana Pardubsk'a 3;??? Walter Unger 2 , Juraj Waczulik 3 , Hubert Wagener 2;y 1 Institut fur Informatik und Praktische Mathematik Universitat zu Kiel, 24098 Kiel, Germany 2 Department of Mathematics and Computer Science University of Paderborn, 33095 Paderborn, Germany 3 Faculty of Mathematics and Physics Comenius University, 84215 Bratislava, Slovakia Abstract. The complexity of systolic dissemination of information in one-way (telegraph) and two-way (telephone) communication mode is investigated. The following main results are established: (i) tight lower and upper bounds on the complexity of one-way systolic gossip in cycles for any length of the systolic period, (ii) optimal one-way and two-way systolic gossip algorithms in 2-dimensional grids whose complexity (the number of rounds) meets the trivial lower bound (the sum of the sizes of its dimensions). The second result (ii) shows that we can systolically gossip in grids wit..

Technologies and Applications for Big Data Value

This open access book explores cutting-edge solutions and best practices for big data and data-driven AI applications for the data-driven economy. It provides the reader with a basis for understanding how technical issues can be overcome to offer real-world solutions to major industrial areas. The book starts with an introductory chapter that provides an overview of the book by positioning the following chapters in terms of their contributions to technology frameworks which are key elements of the Big Data Value Public-Private Partnership and the upcoming Partnership on AI, Data and Robotics. The remainder of the book is then arranged in two parts. The first part “Technologies and Methods” contains horizontal contributions of technologies and methods that enable data value chains to be applied in any sector. The second part “Processes and Applications” details experience reports and lessons from using big data and data-driven approaches in processes and applications. Its chapters are co-authored with industry experts and cover domains including health, law, finance, retail, manufacturing, mobility, and smart cities. Contributions emanate from the Big Data Value Public-Private Partnership and the Big Data Value Association, which have acted as the European data community's nucleus to bring together businesses with leading researchers to harness the value of data to benefit society, business, science, and industry. The book is of interest to two primary audiences, first, undergraduate and postgraduate students and researchers in various fields, including big data, data science, data engineering, and machine learning and AI. Second, practitioners and industry experts engaged in data-driven systems, software design and deployment projects who are interested in employing these advanced methods to address real-world problems

Technologies and Applications for Big Data Value

This open access book explores cutting-edge solutions and best practices for big data and data-driven AI applications for the data-driven economy. It provides the reader with a basis for understanding how technical issues can be overcome to offer real-world solutions to major industrial areas. The book starts with an introductory chapter that provides an overview of the book by positioning the following chapters in terms of their contributions to technology frameworks which are key elements of the Big Data Value Public-Private Partnership and the upcoming Partnership on AI, Data and Robotics. The remainder of the book is then arranged in two parts. The first part “Technologies and Methods” contains horizontal contributions of technologies and methods that enable data value chains to be applied in any sector. The second part “Processes and Applications” details experience reports and lessons from using big data and data-driven approaches in processes and applications. Its chapters are co-authored with industry experts and cover domains including health, law, finance, retail, manufacturing, mobility, and smart cities. Contributions emanate from the Big Data Value Public-Private Partnership and the Big Data Value Association, which have acted as the European data community's nucleus to bring together businesses with leading researchers to harness the value of data to benefit society, business, science, and industry. The book is of interest to two primary audiences, first, undergraduate and postgraduate students and researchers in various fields, including big data, data science, data engineering, and machine learning and AI. Second, practitioners and industry experts engaged in data-driven systems, software design and deployment projects who are interested in employing these advanced methods to address real-world problems

Handbook of sociological science : contributions to rigorous sociology

22 of the 26 chapters are Open AccessThe Handbook of Sociological Science offers a refreshing, integrated perspective on research programs and ongoing developments in sociological science. It highlights key shared theoretical and methodological features, thereby contributing to progress and cumulative growth of sociological knowledge. Reflecting ‘unity in diversity’, chapters explore a wide variety of research fields, ranging from cultural capital, migration, social networks, gender inequality, historical sociology and ethnography to the intersection of sociology and the life sciences. Examining basic methodological standards for theory construction and empirical research, the Handbook exemplifies commonalities between research programmes within these fields. The contributors also explore rigorous sociology related to theory construction, empirical research, and methods, including statistical modelling and the integration of theoretical and empirical research. Forward-thinking and original, the Handbook concludes by illustrating the common core of rigorous sociology, how it can contribute to understanding societal problems and to policy making, and how research into sociological science can continue to thrive in the future. Accessible and engaging, this Handbook will be invaluable for scholars and researchers of sociology and sociological theory, research methods in sociology and social policy, and comparative social policy. Exploring new developments and applications, it will also act as a useful reference guide for policy makers. The Handbook will likewise be an important resource for teaching advanced courses and training graduate students.INTRODUCTION 1. Rigorous sociology 2, Werner Raub, Nan Dirk de Graaf, and Klarita Gërxhani PART I RESEARCH PROGRAMS 2. Order from chaos: sociology as a population science 21, Michelle Jackson 3. Analytical sociology 38, Gianluca Manzo 4. Computational approaches in rigorous sociology: agent-based computational, modeling and computational social science 57, Andreas Flache, Michael Mäs, and Marijn A. Keijzer 5. Stochastic network modeling as generative social science 73, Christian E.G. Steglich and Tom A.B. Snijders 6. Rational choice sociology: heuristic potential, applications, and limitations 100, Andreas Diekmann PART II NEW AND ONGOING DEVELOPMENTS IN SELECTED FIELDS 7. Cultural capital and educational inequality: an assessment of the state of the art 121, Mads Meier Jæger 8. Integration in migration societies 135, Frank Kalter 9. Social networks: effects and formation 154, Vincent Buskens, Rense Corten, and Werner Raub 10. Gender inequality, households, and work 176, Eva Jaspers, Tanja van der Lippe, and Marie Evertsson 11. Validation strategies in historical sociology (and beyond) 196, Ivan Ermakoff 12. Rigorous ethnography 215, Federico Varese 13. Evolution, biology, and society 232, Rosemary L. Hopcroft, Joseph Dippong, Hexuan Liu, and Rachel Kail 14. Sociogenomics: theoretical and empirical challenges of integrating molecular genetics into sociological thinking 250, Melinda C. Mills PART III METHODS 15. Causal inference with observational data 272, Richard Breen 16. Longitudinal designs and models for causal inference 287, Markus Gangl 17. Experimental sociology 309, Klarita Gërxhani and Luis Miller PART IV RIGOROUS SOCIOLOGY IN ACTION: SHOWCASES 18. Explaining educational differentials: towards a formal rational action theory 325, Richard Breen and John H. Goldthorpe 19. ‘Explaining educational differentials’ revisited: an evaluation of rigorous theoretical foundations and empirical findings 356, Rolf Becker 20. Structural holes and good ideas 372, Ronald S. Burt 21. Network mechanisms in innovation: borrowing and sparking ideas around structural holes 423, Balazs Vedres 22. Experimental study of inequality and unpredictability in an artificial cultural market 443, Matthew J. Salganik, Peter Sheridan Dodds, and Duncan J. Watts 23. Self-correcting dynamics in social influence processes 446, Arnout van de Rijt PART V FURTHER PERSPECTIVES 24. The climate crisis: what sociology can contribute 475, Dingeman Wiertz and Nan Dirk de Graaf 25. Roots of sociology as a science: some history of ideas 493, Thomas Voss 26. How to increase reproducibility and credibility of sociological research 512, Katrin Auspurg and Josef Brüderl -- Index 52

Library websites popularity: does Facebook really matter?

The purpose of this paper is to determine whether the utilization of social media (Facebook) is an important factor in increasing the visibility of the library site usage in Malaysian public universities. Nine top ranked Malaysian public universities involved in this research and number of Facebook followers for each library website is listed. Alexa software was used as the approach to study the issue of visibility. Alexa is able to determine web site usage, by showing the percentage of visitors of library related subdomain(s) as listed in the top subdomains for each University website (domain) over a month. It is found that Universiti Utara Malaysia library website scored the highest percentage of visitors based on the library related subdomain(s) as listed in the top subdomains for the University website in Alexa. To check such irregularities in access, this paper use EvalAccess 2.0 and it is found that Universiti Sains Malaysia’s library website scored higher irregularities. In term of number of Facebook followers, Univesity of Malaya library has the highest score. It is showed that the utilization of social media (Facebook) is not yet an important factor in increasing the visibility of the library websites. However, expectedly, top ranked universities’ library web sites, are more visible and popular. This research is limited to the situation in Malaysia where public universities are more noticeable and seldom face financial constraints rather than private universities. It is highly important for those universities’ library web sites that are not highly visible to initiate the necessary measures in improving the development of their web sites as the usage of the website is an indicator of online quality