Data Mining Practical Machine Learning Tools and Techniques

We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

Twitter, a microblogging service less than three years old, commands more than 41 million users as of July 2009 and is growing fast. Twitter users tweet about any topic within the 140-character limit and follow others to receive their tweets. The goal of this paper is to study the topological characteristics of Twitter and its power as a new medium of information sharing.We have crawled the entire Twitter site and obtained 41.7 million user profiles, 1.47 billion social relations, 4,262 trending topics, and 106 million tweets. In its follower-following topology analysis we have found a non-power-law follower distribution, a short effective diameter, and low reciprocity, which all mark a deviation from known characteristics of human social networks [28]. In order to identify influentials on Twitter, we have ranked users by the number of followers and by PageRank and found two rankings to be similar. Ranking by retweets differs from the previous two rankings, indicating a gap in influence inferred from the number of followers and that from the popularity of one's tweets. We have analyzed the tweets of top trending topics and reported on their temporal behavior and user participation. We have classified the trending topics based on the active period and the tweets and show that the majority (over 85%) of topics are headline news or persistent news in nature. A closer look at retweets reveals that any retweeted tweet is to reach an average of 1,000 users no matter what the number of followers is of the original tweet. Once retweeted, a tweet gets retweeted almost instantly on next hops, signifying fast diffusion of information after the 1st retweet.To the best of our knowledge this work is the first quantitative study on the entire Twittersphere and information diffusion on it.

https://ink.library.smu.edu.sg/cgi/viewcontent.cgi?article=7104&context=sis_research

What is Twitter, a social network or a news media?

The term “Linked Data” refers to a set of best practices for publishing and connecting structured data on the Web. These best practices have been adopted by an increasing number of data providers over the last three years, leading to the creation of a global data space containing billions of assertions— the Web of Data. In this article, the authors present the concept and technical principles of Linked Data, and situate these within the broader context of related technological developments. They describe progress to date in publishing Linked Data on the Web, review applications that have been developed to exploit the Web of Data, and map out a research agenda for the Linked Data community as it moves forward.

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Linked Data - the story so far

Obesity now affects one in five children in the United States. Discrimination against overweight children begins early in childhood and becomes progressively institutionalized. Because obese children tend to be taller than their nonoverweight peers, they are apt to be viewed as more mature. The inappropriate expectations that result may have an adverse effect on their socialization. Many of the cardiovascular consequences that characterize adult-onset obesity are preceded by abnormalities that begin in childhood. Hyperlipidemia, hypertension, and abnormal glucose tolerance occur with increased frequency in obese children and adolescents. The relationship of cardiovascular risk factors to visceral fat independent of total body fat remains unclear. Sleep apnea, pseudotumor cerebri, and Blount's disease represent major sources of morbidity for which rapid and sustained weight reduction is essential. Although several periods of increased risk appear in childhood, it is not clear whether obesity with onset early in childhood carries a greater risk of adult morbidity and mortality. Obesity is now the most prevalent nutritional disease of children and adolescents in the United States. Although obesity-associated morbidities occur more frequently in adults, significant consequences of obesity as well as the antecedents of adult disease occur in obese children and adolescents. In this review, I consider the adverse effects of obesity in children and adolescents and attempt to outline areas for future research. I refer to obesity as a body mass index greater than the 95th percentile for children of the same age and gender.

Health Consequences of Obesity in Youth: Childhood Predictors of Adult Disease

In order to improve the quality of food provided in secondary schools, food-based standards (FBS) and nutrient-based standards (NBS) were introduced in 2007 and 2009, respectively. The standards do not apply to packed lunches but schools are encouraged to have a packed lunch policy. Research in primary schools comparing the nutrient intakes of pupils who consume either a school lunch or a packed lunch has shown that, on average, pupils who consume a school lunch typically have a more favourable intake of key nutrients, to date no similar comparison has been carried out in secondary schools. In 2008, the School Food Trust studied the effect in secondary schools of improving school food and the meal experience on pupil’s postprandial behaviour in the classroom. Ethical approval was obtained from Kings College London Research Ethics Committee. Lunchtime food and drink choices of pupils consuming either a school lunch or a packed lunch were recorded at eleven secondary schools. Portion sizes were either weighed or estimated by weighing duplicate portions of foods provided at the schools. Leftovers were weighed to calculate the amount of each food eaten by each child. Baseline data from this study were used to compare mean energy and nutrient intakes from school lunches and packed lunches.

/pdf/comparison-between-school-lunches-and-packed-lunches-in-7mdu9paodp.pdf

Comparison between school lunches and packed lunches in secondary schools

When a user requests a web page from a web archive, the user will typically either get an HTTP 200 if the page is available, or an HTTP 404 if the web page has not been archived. This is because web archives are typically accessed by Uniform Resource Identifier (URI) lookup, and the response is binary: the archive either has the page or it does not, and the user will not know of other archived web pages that exist and are potentially similar to the requested web page. In this paper, we propose augmenting these binary responses with a model for selecting and ranking recommended web pages in a Web archive. This is to enhance both HTTP 404 responses and HTTP 200 responses by surfacing web pages in the archive that the user may not know existed. First, we check if the URI is already classified in DMOZ or Wikipedia. If the requested URI is not found, we use machine learning to classify the URI using DMOZ as our ontology and collect candidate URIs to recommended to the user. The classification is in two parts, a first-level classification and a deep classification. Next, we filter the candidates based on if they are present in the archive. Finally, we rank candidates based on several features, such as archival quality, web page popularity, temporal similarity, and URI similarity. We calculated the F1 score for different methods of classifying the requested web page at the first level. We found that using all-grams from the URI after removing numerals and the top-level domain (TLD) produced the best result with F1 =0.59. For the deep-level classification, we measured the accuracy at each classification level. For second-level classification, the micro-average F1=0.30 and for third-level classification, F1=0.15. We also found that 44.89% of the correctly classified URIs contained at least one word that exists in a dictionary and 50.07% of the correctly classified URIs contained long strings in the domain. In comparison with the URIs from our Wayback access logs, only 5.39% of those URIs contained only words from a dictionary, and 26.74% contained at least one word from a dictionary. These percentages are low and may affect the ability for the requested URI to be correctly classified.

Making Recommendations from Web Archives for

In previous work we reported that resources linked in tweets disappeared at the rate of 11% in the first year followed by 7.3% each year afterwards. We also found that in the first year 6.7%, and 14.6% in each subsequent year, of the resources were archived in public web archives. In this paper we revisit the same dataset of tweets and find that our prior model still holds and the calculated error for estimating percentages missing was about 4%, but we found the rate of archiving produced a higher error of about 11.5%. We also discovered that resources have disappeared from the archives themselves (7.89%) as well as reappeared on the live web after being declared missing (6.54%). We have also tested the availability of the tweets themselves and found that 10.34% have disappeared from the live web. To mitigate the loss of resources on the live web, we propose the use of a "tweet signature". Using the Topsy API, we extract the top five most frequent terms from the union of all tweets about a resource, and use these five terms as a query to Google. We found that using tweet signatures results in discovering replacement resources with 70+% textual similarity to the missing resource 41% of the time.

Resurrecting My Revolution: Using Social Link Neighborhood in Bringing Context to the Disappearing Web

Background Women with HIV (WWH) face heightened risks of heart failure; however, insights on immune/inflammatory pathways potentially contributing to left ventricular (LV) systolic dysfunction among WWH remain limited. Setting Massachusetts General Hospital, Boston, Massachusetts. Methods Global longitudinal strain (GLS) is a sensitive measure of LV systolic function, with lower cardiac strain predicting incident heart failure and adverse heart failure outcomes. We analyzed relationships between GLS (cardiovascular magnetic resonance imaging) and monocyte activation (flow cytometry) among 20 WWH and 14 women without HIV. Results WWH had lower GLS compared to women without HIV (WWH vs. women without HIV: 19.4±3.0 vs. 23.1±1.9%, P<0.0001). Among the whole group, HIV status was an independent predictor of lower GLS. Among WWH (but not among women without HIV), lower GLS related to a higher density of expression of HLA-DR on the surface of CD14+CD16+ monocytes (ρ = -0.45, P = 0.0475). Further, among WWH, inflammatory monocyte activation predicted lower GLS, even after controlling for CD4+ T-cell count and HIV viral load. Conclusions Additional studies among WWH are needed to examine the role of inflammatory monocyte activation in the pathogenesis of lower GLS and to determine whether targeting this immune pathway may mitigate risks of heart failure and/or adverse heart failure outcomes. Trial registration Clinical trials.gov registration: NCT02874703.

Cardiac strain is lower among women with HIV in relation to monocyte activation

NASA Langley Research Center''s product is aerospace research information. To this end, Langley uses information technology tools in three distinct ways. First, information technology tools are used in the production of information via computation, analysis, data collection and reduction. Second, information technology tools assist in streamlining business processes, particularly those that are primarily communication based. By applying these information tools to administrative activities, Langley spends fewer resources on managing itself and can allocate more resources for research. Third, Langley uses information technology tools to disseminate its aerospace research information, resulting in faster turn around time from the laboratory to the end-customer. This paper describes how information technology tools are currently cutting cost and adding value for NASA Langley internal and external customers. Three components from a larger strategic WWW framework are highlighted: Geographic Information Systems (GIS), Integrated Computer Environment (ICE), and LANTERN (Langley''s Intranet). Based on experiences with these and related projects at Langley, we suggest that there are four pillars of information technology project success: training; provision of useful services; access to enabling tools; and advertising and advocacy.

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Michael L. Nelson

Papers

Comparison between school lunches and packed lunches in secondary schools

Making Recommendations from Web Archives for

Resurrecting My Revolution: Using Social Link Neighborhood in Bringing Context to the Disappearing Web

Cardiac strain is lower among women with HIV in relation to monocyte activation

Integrating information technologies into large organizations