Do Diffusion Protocols Govern Cascade Growth?

Large cascades can develop in online social networks as people share information with one another. Though simple reshare cascades have been studied extensively, the full range of cascading behaviors on social media is much more diverse. Here we study how diffusion protocols, or the social exchanges that enable information transmission, affect cascade growth, analogous to the way communication protocols define how information is transmitted from one point to another. Studying 98 of the largest information cascades on Facebook, we find a wide range of diffusion protocols - from cascading reshares of images, which use a simple protocol of tapping a single button for propagation, to the ALS Ice Bucket Challenge, whose diffusion protocol involved individuals creating and posting a video, and then nominating specific others to do the same. We find recurring classes of diffusion protocols, and identify two key counterbalancing factors in the construction of these protocols, with implications for a cascade's growth: the effort required to participate in the cascade, and the social cost of staying on the sidelines. Protocols requiring greater individual effort slow down a cascade's propagation, while those imposing a greater social cost of not participating increase the cascade's adoption likelihood. The predictability of transmission also varies with protocol. But regardless of mechanism, the cascades in our analysis all have a similar reproduction number ($\approx$ 1.8), meaning that lower rates of exposure can be offset with higher per-exposure rates of adoption. Last, we show how a cascade's structure can not only differentiate these protocols, but also be modeled through branching processes. Together, these findings provide a framework for understanding how a wide variety of information cascades can achieve substantial adoption across a network.Comment: ICWSM 201

From the Open Skies proposal of 1955 to the Norstad Plan 1960: a plan too far

A proposal drafted by General Lauris Norstad for the creation of a limited inspection zone in Central Europe and in the Arctic Circle—a proposal that came to be known as the Norstad Plan—evolved out of President Dwight D. Eisenhower's Open Skies proposal. The proposal, based on ideas promoted by Eisenhower's disarmament adviser, Harold Stassen, departed from traditional U.S. disarmament policy. The plan was eventually aborted by West Germany and France, but the document heralded a shift in Eisenhower's disarmament policy. The president was ready to give up the all-or-nothing approach and adopt an incremental approach. To this end, the United States would make concessions that would render U.S. proposals more acceptable to the Soviet Union. The plan adumbrated the conceptual change that paved the way for the Limited Nuclear Test Ban Treaty and the Non-Proliferation Treaty

Tigard-Tualatin School District Enrollment Forecast Update, 2011-12 to 2020-21

This report presents the results of a demographic study conducted by the Portland State University Population Research Center (PRC). The study includes analysis of population, housing and enrollment trends affecting the District in recent years, estimates of the impacts of housing development on TTSD enrollment, and forecasts of districtwide and individual school enrollments for the 2011-12 to 2020-21 school years. The Tigard-Tualatin School District (TTSD) enrolled 12,393 students in Fall 2010, a decrease of 74 students (0.6 percent) from Fall 2009. The loss occurred at both the elementary and middle school levels, with decreases of 41 students (0.7 percent) in grades K-5 and 123 students (4.2 percent) in grades 6-8. Conversely, district-wide enrollment in high school grades 9-12 increased by 90 students (2.3 percent)

Bend-La Pine School District: Population and Enrollment Forecasts 2010-11 to 2030-31

The Bend-La Pine School District (BLPSD) enrolled 15,898 students in Fall 2009, an increase of 61 students from Fall 2008. This followed a loss of 13 students between Fall 2007 and Fall 2008. These two most recent years are in sharp contrast with the previous 19 years of uninterrupted gains of more than 200 students each year. K-12 enrollment growth averaged about 350 students per year from 1990 to 2000, and about 400 students per year from 2000 to 2007. The enrollment trends align closely with the housing and employment trends described in this report. Housing growth began to slow early in 2007, job losses became evident by the end of 2007, and the migration of families with children into the District tapered off beginning in 2008. In spite of this slowdown, there is still momentum from the District’s recent high population growth and increase in births. All school levels, elementary, middle, and high, remain at or near their all time high enrollments. Kindergarten and 1st grade enrollments, typically the leading indicators of shifting enrollment trends, have not declined. They were each slightly larger in Fall 2009 than in Fall 2007. The primary purpose of this study by the Portland State University Population Research Center (PRC) is to provide school Enrollment Forecasts that will be used by the District, Deschutes County, and the City of Bend for long range planning. These district-wide forecasts by grade level for the BLPSD are consistent with the Deschutes County Coordinated Population Forecast (DCCPF) adopted by the Deschutes County Board of Commissioners in September 2004

Portland Public Schools Enrollment Forecasts, 2011-12 to 2025-26, Based on October 2010 Enrollments

In Fall 2011, Portland Public Schools (PPS) enrolled 46,206 students in grades K-12, an increase of 465 students from Fall 2010. This is the third consecutive year of enrollment growth, following 12 consecutive years of enrollment losses that occurred between 1996- 97 and 2008-09. For the three year period since 2008-09, PPS K-12 enrollment has grown by 1,182 students, or 2.6 percent. In seven of the past eight years, actual K-12 enrollment in the first year of the forecast has been within 300 students of the medium scenario characterized as the “most likely” Enrollment Forecast in reports similar to this one. However, in all eight of those years actual enrollment was higher than the one year medium scenario forecast. Fall 2011 K- 12 enrollment was 227 students (0.5 percent) higher than the medium scenario forecast but 27 students (0.1 percent) lower than the high scenario forecast prepared in Spring 2011. The Enrollment Forecasts in this report were prepared in Spring and Summer 2011, based on historic enrollment data from 2010-11 and previous years. However, the entire report was not ready for publication until after 2011-12 enrollment data became available. This preface briefly addresses the district-wide trends observed in 2011-12 and evaluates the forecasts in the short term. The next report will include more analysis of enrollment trends with respect to area demographics and trends within sub-areas such as high school clusters. The 2011-12 enrollment figures in this preface were published by the District on November 18, 2011

Oregon City School District Enrollment Forecasts, 2010-11 to 2019-20

This report presents the results of a demographic study conducted by the Portland State University Population Research Center. The study includes analyses of population, housing and enrollment trends affecting the District in recent years, low, middle, and high range forecasts of district-wide enrollment by grade level for the 2010-11 to 2019-20 school years and middle range forecasts of individual school enrollments for the 2010-11 to 2014-15 school years. The District’s K-12 enrollment of 7,764 in 2009-10 was 232 students (2.9 percent) below its 2004-05 peak enrollment of 7,796 students. The 2008-09 to 2009-10 loss of 114 students (1.4 percent) was the District’s biggest K-12 enrollment decline in more than 20 years. Despite the overall loss, kindergarten and 1st grade enrollments experienced a third consecutive year of small enrollment increases

North Clackamas School District Enrollment Forecasts, 2011-12 to 2020-21

This report presents the results of a demographic study conducted by the Portland State University Population Research Center (PRC). The study includes analysis of population, housing and enrollment trends affecting the North Clackamas School District (NCSD) in recent years and forecasts of district-wide and individual school enrollments for the 2011-12 to 2020-21 school years. The District enrolled 17,368 students in Fall 2010, a decrease of 210 students (1.2 percent) from Fall 2009. This was the second consecutive year of decline in enrollment following 22 consecutive years of K-12 enrollment growth between 1986-87 and 2008- 09. This year, for the first time in at least 20 years, total enrollment in schools east of I- 205 did not grow. The Clackamas Feeder System total enrollment was basically unchanged from Fall 2009, with a net loss of 15 students. The Milwaukie and Rex Putnam feeder systems had net enrollment losses of 86 and 72 students respectively. The losses at schools west of I-205 were consistent with long term trends but much smaller than in the previous year, between Fall 2008 and Fall 2009

MCTS/EA hybrid GVGAI players and game difficulty estimation

© 2016 IEEE. In the General Video Game Playing competitions of the last years, Monte-Carlo tree search as well as Evolutionary Algorithm based controllers have been successful. However, both approaches have certain weaknesses, suggesting that certain hybrids could outperform both. We envision and experimentally compare several types of hybrids of two basic approaches, as well as some possible extensions. In order to achieve a better understanding of the games in the competition and the strength and weaknesses of different controllers, we also propose and apply a novel game difficulty estimation scheme based on several observable game characteristics

Major flaws in conflict prevention policies towards Africa : the conceptual deficits of international actors’ approaches and how to overcome them

Current thinking on African conflicts suffers from misinterpretations oversimplification, lack of focus, lack of conceptual clarity, state-centrism and lack of vision). The paper analyses a variety of the dominant explanations of major international actors and donors, showing how these frequently do not distinguish with sufficient clarity between the ‘root causes’ of a conflict, its aggravating factors and its triggers. Specifically, a correct assessment of conflict prolonging (or sustaining) factors is of vital importance in Africa’s lingering confrontations. Broader approaches (e.g. “structural stability”) offer a better analytical framework than familiar one-dimensional explanations. Moreover, for explaining and dealing with violent conflicts a shift of attention from the nation-state towards the local and sub-regional level is needed.Aktuelle Analysen afrikanischer Gewaltkonflikte sind häufig voller Fehlinterpretationen (Mangel an Differenzierung, Genauigkeit und konzeptioneller Klarheit, Staatszentriertheit, fehlende mittelfristige Zielvorstellungen). Breitere Ansätze (z. B. das Modell der Strukturellen Stabilität) könnten die Grundlage für bessere Analyseraster und Politiken sein als eindimensionale Erklärungen. häufig differenzieren Erklärungsansätze nicht mit ausreichender Klarheit zwischen Ursachen, verschärfenden und auslösenden Faktoren. Insbesondere die richtige Einordnung konfliktverlängernder Faktoren ist in den jahrzehntelangen gewaltsamen Auseinandersetzungen in Afrika von zentraler Bedeutung. Das Diskussionspapier stellt die große Variationsbreite dominanter Erklärungsmuster der wichtigsten internationalen Geber und Akteure gegenüber und fordert einen Perspektivenwechsel zum Einbezug der lokalen und der subregionalen Ebene für die Erklärung und Bearbeitung gewaltsamer Konflikte