In the form of topic discussions, users interact with each other to share knowledge and exchange information in online forums. Modeling the evolution of topic discussion reveals how information propagates on Internet and can thus help understand sociological phenomena and improve the performance of applications such as recommendation systems. In this paper, we argue that a user’s participation ...

Viral marketing can be an effective marketing technique in social networks. Initiating from a set of influential seed users, it can activate a ‘‘chain-reaction’’ driven by word-of-mouth. The effectiveness of viral marketing lies in the fact that it conveys an implied endorsement from social ties. Existing approaches to selecting influential seeds depend on measures of global centrality within t...

This study includes a global sensitivity analysis of the water productivity model AquaCrop. The study rationale consisted in a comprehensive evaluation of the model and the formulation of guidelines for model simplification and efficient calibration. The global analysis comprehended a Morris screening followed by a variance-based Extended Fourier Amplitude Sensitivity Test (EFAST) under diverse...

Social network services (SNSs) have become new global and multilingual information platforms due to their popularity. In SNSs with content-sharing functionality, such as "retweets'' in Twitter and "share'' in Facebook, posts are easily and quickly shared among users, and some grow into large information cascades. Accompanied with such growth, cascades can spread over regions and languages. The ...

One single code change can significantly influence a wide range of software systems and their users. For example, 1) adding a new feature can spread defects in several modules, while 2) changing an API method can improve the performance of all client programs. Developers often may not clearly know whether their or others’ changes are influential at commit time. Rather, it turns out to be influe...

Identifying influential spreaders is an important issue in understanding the dynamics of information diffusion in social networks. It is to find a small subset of nodes, which can spread the information or influence to the largest number of nodes. The conventional approaches consider information diffusion through the network in a coarse-grained manner, without taking into account the topical fe...

1 Formal Logic with Conceptual Graphs 3 Frithjof Dau 1.

G(u,u',u") = 0, (1) where u = u(x, x,..., x), and u', u" denote all the first and second partial derivatives of u. For simplicity we will assume here that both u and G are scalars and denote by ua, uab, the partial derivatives dau and respectively dahu; a,b =1,2, ..., n+1. Let u (x) be a given solution of (1). Our equation is said to be elliptic or hyperbolic at u°(x) according to whether the (...

We consider the problem of designing optimal linear codes (in terms of having the largest minimum distance) subject to a support constraint on the generator matrix. We show that the largest minimum distance can be achieved by a subcode of a Reed-Solomon code of small field size. As a by-product of this result, we settle the GM-MDS conjecture of Dau et. al. in the affirmative.

Perhaps the fastest growing arena in the World Wide Web is the space of social networking sites (e.g., Friendster, Facebook, MySpace). The success of these sites directly depends on the number and activity level of their users. What attracts users to the site is a continually changing digital content (e.g., messages, pictures, photos, music, videos, blogs) generated by other users. In contrast,...