1,720,964 research outputs found
Recommended from our members
Throughput and Delay on the Packet Switched Internet
Get PDFThe Internet has become a vital and essential part of modern everyday life. Services delivered by the Internet are used by people across the planet every moment of every day of the year. The Internet has proven a positive force for good improving the lives of billions of people worldwide. The power of the Internet to deliver this positive good to humanity relies on its ability to deliver life improving services. In my doctorate work culminating in this dissertation I have striven to sustain and increase the Internet's ability to deliver these services and to have a positive good effect upon humanity.The overarching purpose of this dissertation is to improve the Internet's ability to deliver life improving services. I have further divided this purpose into two goals. To improve the ability of applications operating in challenging network conditions to gain their fair share of the bandwidth resources and to reduce the delay with which these services are delivered. Every service delivered by the Internet consists of Internet objects that are delivered through communication paths across the Internet. The delivery of these objects is defined by the two characteristics; Throughput and delay. Throughput determines how much of an object can be delivered over a period of time and delay determines how long it takes to deliver an object.These two characteristics determine the Internet's ability to deliver objects across communication paths. Improving these two characteristics (bandwidth and delay) increase the ability of the Internet to deliver objects and thus improve the Internet's capability to deliver life improving services. To accomplish this goal I present projects along three areas of effort. These three areas of effort are: (1) Increase the ability of applications operating in challenging conditions to achieve their fair share of bandwidth. (2) Synthesize knowledge required to address the effort to reduce delay. (3) Develop protocols that reduce delay encountered in the communications paths of the Internet.In this dissertation I present projects along these three areas of effort that accomplish the two goals (increase bandwidth and reduce delay) to achieve the purpose of improving the Internet's ability to deliver essential and life improving services. These projects and their organization into areas of effort, goals and purpose are my contributions to the networking sciences
Formal Modeling of Service Session Management
Get PDFThis paper proposes a concept to apply modeling tools to Multi-Provider Telematics Service Management. The service architecture is based on the framework called “Open Service Components” which serves as building blocks to compose end-to-end telematics services in terms of service components offered by different service providers. Our work presented in this paper contributes to the abstract way of modeling end-to-end Service Management using Architectural Description Language and an underlying Formal Description Language
Recommended from our members
Resource-Efficient Wireless Systems for Emerging Wireless Networks
Get PDFAs the wireless medium has become the primary source of communication and Internet connectivity, and as devices and wireless technologies become more sophisticated and capable, there has been a surge in the capacity demands and complexity of applications that run over these wireless devices. To sustain the volume and QoE guarantees of the data generated, the opportunity and need to rethink wireless network design across all the layers of the protocol stack has firmly emerged as a solution to enable the timely and reliable delivery of data, while handling the inherent challenges of a crowded wireless medium, such as congestion, interference, and hidden terminals. The research work presented in this dissertation builds efficient solutions and protocols with a theoretical foundation to address the challenges that arise in rethinking wireless network design. Example challenges include managing the overhead associated with complex systems. My work particularly focuses on the opportunities and challenges of sophisticated technology and systems in emerging wireless networks. I target the main thrusts in the evolution of wireless networks that create significant opportunity to achieve higher theoretical capacity, and have direct implications on our day-to-day wireless interactions: from enabling multifold increase in capacity in wireless physical links, to developing medium access techniques to exploit the high speed links, and making the applications more bandwidth efficient. I build deployable, and resource-aware wireless systems that exploit higher bandwidths by leveraging and advancing diverse research areas such as theory, analysis, protocol design, and wireless networking. Specifically, I identify the erroneous assumptions and fundamental limitations of existing solutions in capturing the true and complex interactions between wireless devices and protocols. I use these insights to guide practical and efficient protocol design, followed by thorough analysis and evaluation in testbed implementations via prototypes and measurements. I show that my proposed solutions achieve significant performance gains, at minimum cost to overhead
Proceedings of the 2013 International News Recommender Systems Workshop and Challenge
No full textNews article recommendation differs in several ways from other well-known types of recommender systems such as for music and movies. First, freshness represents an important aspect. Sometimes, freshness is deemed more important than relevancy. Second, similarity between news articles does not necessarily reflect their relatedness. For instance, two news articles might share a majority of words. Still, their actual topic might differ. Third, news are typically published in a rather unstructured format. In contrast, structured data such as social graphs facilitate pre-processing steps. Fourth, news readers might have special preferences on some particular events which recommender systems can barely predict. Fifth, serendipities (i. e., variety in recommended news articles) represent a crucial property of a news recommender system. Contrarily to music recommendations, users avoid to re-consume an item. Thus, news recommender systems are required to provide diverse sets of items in order to assure not to recommend monotonously. Sixth, breaking or trendy news might have a high relevance even though the appear completely unrelated to the individual user profile. Seventh, the has not yet established consensus on how to evaluate news recommender systems. We typically observe implicit preferences as users interact with news portals. Those preferences do not exhibit a graded relevance. Thus, well-established evaluation criteria based on ratings (e.g., root mean squared error) cannot be applied. Another set of challenges arises from the context of news recommendation. Recommender systems are known to struggle with so-called "cold-start users" (i. e., users form whom no preferences are available yet). News portals typically refrain to require users to login prior to read news articles. Hence, there is a large fraction of users who appear to be "cold-start users". The lack of sufficiently many interaction to established trustworthy user profiles entails further challenges. Inferring interest signals suffers from incomplete profiles. Additionally, items' relevance is time dependent and diminishes with time progressing. Another challenge related to the context arises from the increasingly frequent use of mobile devices to read news articles such as tablets and smart phones. Those have a limited space available to display news and related recommendations. News recommender systems have to deal with this issue thus applying suited layout mechanisms to fit the content to the available screen. Finally, news recommender systems face numerous technical challenges. Those challenges include minimizing response time improve user experience, scaling to the large amount of requests to avoid time outs, providing flexibility to incorporate new recommendation methods or adjust parameter settings for existing implementations, and guarantee a reliable service whom user can access at any time
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Proceedings of the 2013 International News Recommender Systems Workshop and Challenge
No full textNews article recommendation differs in several ways from other well-known types of recommender systems such as for music and movies. First, freshness represents an important aspect. Sometimes, freshness is deemed more important than relevancy. Second, similarity between news articles does not necessarily reflect their relatedness. For instance, two news articles might share a majority of words. Still, their actual topic might differ. Third, news are typically published in a rather unstructured format. In contrast, structured data such as social graphs facilitate pre-processing steps. Fourth, news readers might have special preferences on some particular events which recommender systems can barely predict. Fifth, serendipities (i. e., variety in recommended news articles) represent a crucial property of a news recommender system. Contrarily to music recommendations, users avoid to re-consume an item. Thus, news recommender systems are required to provide diverse sets of items in order to assure not to recommend monotonously. Sixth, breaking or trendy news might have a high relevance even though the appear completely unrelated to the individual user profile. Seventh, the has not yet established consensus on how to evaluate news recommender systems. We typically observe implicit preferences as users interact with news portals. Those preferences do not exhibit a graded relevance. Thus, well-established evaluation criteria based on ratings (e.g., root mean squared error) cannot be applied. Another set of challenges arises from the context of news recommendation. Recommender systems are known to struggle with so-called "cold-start users" (i. e., users form whom no preferences are available yet). News portals typically refrain to require users to login prior to read news articles. Hence, there is a large fraction of users who appear to be "cold-start users". The lack of sufficiently many interaction to established trustworthy user profiles entails further challenges. Inferring interest signals suffers from incomplete profiles. Additionally, items' relevance is time dependent and diminishes with time progressing. Another challenge related to the context arises from the increasingly frequent use of mobile devices to read news articles such as tablets and smart phones. Those have a limited space available to display news and related recommendations. News recommender systems have to deal with this issue thus applying suited layout mechanisms to fit the content to the available screen. Finally, news recommender systems face numerous technical challenges. Those challenges include minimizing response time improve user experience, scaling to the large amount of requests to avoid time outs, providing flexibility to incorporate new recommendation methods or adjust parameter settings for existing implementations, and guarantee a reliable service whom user can access at any time
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
