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Full-Text Articles in Physical Sciences and Mathematics
Preparing Computer Science Graduates For The 21st Century, Paul Parsons
Preparing Computer Science Graduates For The 21st Century, Paul Parsons
Paul Parsons
The nature of computer use has changed remarkably in the past fifty years. However, most undergraduate computer science courses are still often taught through an old paradigm that is not adequate to address modern concerns. This 90 minute seminar will address some issues relevant to preparing computer scientists for the 21st century. These include issues central to human-computer interaction (HCI) such as cognitive and perceptual aspects of computer users, ergonomics, and human factors. Although there has been literature on this topic for at least the past 15 years, it is still not widely recognized nor understood by the majority of …
Residual-Based Measurement Of Peer And Link Lifetimes In Gnutella Networks, Xiaoming Wang, Zhongmei Yao, Dmitri Loguinov
Residual-Based Measurement Of Peer And Link Lifetimes In Gnutella Networks, Xiaoming Wang, Zhongmei Yao, Dmitri Loguinov
Zhongmei Yao
Existing methods of measuring lifetimes in P2P systems usually rely on the so-called create-based method (CBM), which divides a given observation window into two halves and samples users "created" in the first half every Delta time units until they die or the observation period ends. Despite its frequent use, this approach has no rigorous accuracy or overhead analysis in the literature. To shed more light on its performance, we flrst derive a model for CBM and show that small window size or large Delta may lead to highly inaccurate lifetime distributions. We then show that create-based sampling exhibits an inherent …
On Node Isolation Under Churn In Unstructured P2p Networks With Heavy-Tailed Lifetimes, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov
On Node Isolation Under Churn In Unstructured P2p Networks With Heavy-Tailed Lifetimes, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov
Zhongmei Yao
Previous analytical studies [12], [18] of unstructured P2P resilience have assumed exponential user lifetimes and only considered age-independent neighbor replacement. In this paper, we overcome these limitations by introducing a general node-isolation model for heavy-tailed user lifetimes and arbitrary neighbor-selection algorithms. Using this model, we analyze two age-biased neighbor-selection strategies and show that they significantly improve the residual lifetimes of chosen users, which dramatically reduces the probability of user isolation and graph partitioning compared to uniform selection of neighbors. In fact, the second strategy based on random walks on age-weighted graphs demonstrates that for lifetimes with infinite variance, the system …
Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang
Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang
Zhongmei Yao
Previous analytical results on the resilience of unstructured P2P systems have not explicitly modeled heterogeneity of user churn (i.e., difference in online behavior) or the impact of in-degree on system resilience. To overcome these limitations, we introduce a generic model of heterogeneous user churn, derive the distribution of the various metrics observed in prior experimental studies (e.g., lifetime distribution of joining users, joint distribution of session time of alive peers, and residual lifetime of a randomly selected user), derive several closed-form results on the transient behavior of in-degree, and eventually obtain the joint in/out degree isolation probability as a simple …
Legal Issues: Security And Privacy With Mobile Devices, Brian Leonard, Maurice Dawson
Legal Issues: Security And Privacy With Mobile Devices, Brian Leonard, Maurice Dawson
Maurice Dawson
Privacy and security are two items being woven into the fabric of American law concerning mobile devices. This chapter will review and analyze the associated laws and policies that are currently in place or have been proposed to ensure proper execution of security measures for mobile and other devices while still protecting individual privacy. This chapter will address the fact that as the American society significantly uses mobile devices, it is imperative to understand the legal actions surrounding these technologies to include their associated uses. This chapter will also address the fact that with 9/11 in the not so distant …