Web User Session Characterization via Clustering Techniques

We focus on the identification and definition of "Web user-sessions", an aggregation of several TCP connections generated by the same source host on the basis of TCP connection opening time. The identification of a user session is non trivial; traditional approaches rely on threshold based mechanisms, which are very sensitive to the value assumed for the threshold and may be difficult to correctly set. By applying clustering techniques, we define a novel methodology to identify Web user-sessions without requiring an a priori definition of threshold values. We analyze the characteristics of user sessions extracted from real traces, studying the statistical properties of the identified sessions. From the study it emerges that Web user-sessions tend to be Poisson, but correlation may arise during periods of network/hosts anomalous functioning

Web User-session Inference by Means of Clustering Techniques

This paper focuses on the definition and identification of “Web user-sessions”, aggregations of several TCP connections generated by the same source host. The identification of a user-session is non trivial. Traditional approaches rely on threshold based mechanisms. However, these techniques are very sensitive to the value chosen for the threshold, which may be difficult to set correctly. By applying clustering techniques, we define a novel methodology to identify Web user-sessions without requiring an a priori definition of threshold values. We define a clustering based approach, we discuss pros and cons of this approach, and we apply it to real traffic traces. The proposed methodology is applied to artificially generated traces to evaluate its benefits against traditional threshold based approaches. We also analyze the characteristics of user-sessions extracted by the clustering methodology from real traces and study their statistical properties. Web user-sessions tend to be Poisson, but correlation may arise during periods of network/hosts anomalous behavior

Unregulated Custody Transfers: Why the Practice of Rehoming Should Be Considered a Form of Illegal Adoption and Human Trafficking

In this work, the authors prepared and characterized two different graphene oxides: one chemically synthesized (GO sample) and the other one electrochemically synthesized (GO(LiCl)). Both samples were fully characterized with atomic force microscopy (AFM), Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray photo electron spectroscopy (XPS), thermal analysis (TG/DTA), and Z-potential. The antibacterial properties of both graphene oxides were studied using Gram-negative Escherichia coli ATCC 25922 and Gram-positive Staphylococcus aureus ATCC 25923 by spectrophotometer and viable cell count as indirect and direct methods, respectively. Results demonstrated that the GO(LiCl) exhibited a significant antibacterial activity compared to GO that showed a bacteriostatic effect on both pathogens. Electron microscopy analysis confirmed the antibacterial effects of both graphene oxides toward the pathogens, especially working at 80 μg/mL, for 24 h. Additional studies were also performed and both GO samples were not cytotoxic at 2 μg/mL toward neuroblastoma cells. Moreover, 2 μg of GO was suitable to carry the minimum effective dose (5.74 ng/mL) of kinase inhibitor S29 (1-(2-chloro-2-(4-chlorophenyl)ethyl)-N-(4-fluorobenzyl)-1H-pyrazolo[3,4-d] pyrimidin-4-amine), providing negligible side effects related to the S29 treatment (this latter being specifically active on the neuroblastoma cell lines (SK-N-BE(2)))

Admission control and path allocation for SLAs in DiffServ networks

In this paper we consider a Differentiated Service domain, in which the domain administrator has to decide whether to accept or to reject service level agreements (SLA) requested by users. After introducing the admission criteria which are used to verify if there are enough resources to satisfy the SLA request, we focus our attention to the problem of the SLA routing, i.e., the selection of paths along which traffic may flow. In particular, we show that the construction of an optimal set of paths is equivalent to the construction of a multicast tree, or a Steiner tree which is known to be an NP-hard problem. We therefore propose a class of simple heuristics, whose performance is assessed by simulations. Results show that it is possible to increase up to 40% the amount of capacity a network provider can reserve to SLA requests without violating the QoS constraints or to reduce the SLA blocking probability by a order of magnitude by using the proposed algorithms