Behavior-Based Outlier Detection for Network Access Control Systems

Network Access Control (NAC) systems manage the access of new devices into enterprise networks to prevent unauthorised devices from attacking network services. The main difficulty with this approach is that NAC cannot detect abnormal behaviour of devices connected to an enterprise network. These abnormal devices can be detected using outlier detection techniques. Existing outlier detection techniques focus on specific application domains such as fraud, event or system health monitoring. In this paper, we review attacks on Bring Your Own Device (BYOD) enterprise networks as well as existing clustering-based outlier detection algorithms along with their limitations. Importantly, existing techniques can detect outliers, but cannot detect where or which device is causing the abnormal behaviour. We develop a novel behaviour-based outlier detection technique which detects abnormal behaviour according to a device type profile. Based on data analysis with K-means clustering, we build device type profiles using Clustering-based Multivariate Gaussian Outlier Score (CMGOS) and filter out abnormal devices from the device type profile. The experimental results show the applicability of our approach as we can obtain a device type profile for five dell-netbooks, three iPads, two iPhone 3G, two iPhones 4G and Nokia Phones and detect outlying devices within the device type profile

More than words: text art since conceptualism

Since 2009, there has been an increased presence of group exhibitions in public institutions in the UK and the US which address the ways contemporary artists in the past two decades have used text as a material, a subject, and a conceptual device. Significant amongst these exhibitions are Poor. Old. Tired. Horse. held at the Institute of Contemporary Art in London in 2009, and Ecstatic Alphabets/Heaps of Language held at the Museum of Modern Art in New York in 2012. Within their curatorial strategies, and independently from one another, both exhibitions draw a binary of the genealogy of text in art practice as emerging either from the international movement of concrete poetry of the mid-1950s to 1971 (including the work of Décio Pignatari, or Haraldo de Campos), or from conceptual art of the mid-1960s-early 1970s (including the work of Joseph Kosuth, Art & Language, Robert Smithson, or Mel Bochner). Such group exhibitions have overlooked how feminist, second generation conceptual artists embraced language as material. Artists of this second generation of conceptual art were critiquing conceptualism by introducing subject matter which looked outward from art and which demanded the audience to engage with language as a material through their use of the printed word, typography, written language, and methods of printing. For these artists, such as Mary Kelly, language was not presumed natural, and the materiality of text was necessary in order to engage an art audience in questions of power, representation, gender, and socialisation. With the rise of the digital age, the materiality of the linguistic signifier offers artists today something different than it did in the 1960s. Since the late 1990s, there has been a proliferation of works by contemporary artists in the UK and US that I refer to as text art, made by artists such as Fiona Banner, Janice Kerbel, Shannon Ebner, Pavel Büchler, or Paul Elliman. Part of my original contribution to knowledge is to explore the ways contemporary artists use text, to interrogate how this is different from work seen before, and to question the demands it places on the audience who reads it, as well as the challenges it places on the act of reading an artwork made of words. The literature emphasises a turn away from looking or the visual to a turn towards reading which occurred in conceptualism (Kotz, 2007; Blacksell, 2013). I explore the binary of this turn in the conceptual art period of 1966-1973 and I suggest that artists are engaging with text today not only to challenge how an audience encounters written language as art, but the very act of reading text in a digital world. The first three chapters explore the materiality of text in a historical genealogy of conceptual art, conceptual art in relationship to concrete poetry, and the feminist critique in second generation of conceptual art. The latter three chapters explore the materiality of text in contemporary art practices. This is the focus of the thesis, which builds on the foundation for materiality of text argued in chapters one, two, and three. I argue not for a cohesive movement of contemporary text artists, but rather, that diverse, contemporary artists’ practices are making similar investigations across text in art, and that this warrants attention to explore how we consider text as a medium today

Two Algorithms for Orthogonal Nonnegative Matrix Factorization with Application to Clustering

Approximate matrix factorization techniques with both nonnegativity and orthogonality constraints, referred to as orthogonal nonnegative matrix factorization (ONMF), have been recently introduced and shown to work remarkably well for clustering tasks such as document classification. In this paper, we introduce two new methods to solve ONMF. First, we show athematical equivalence between ONMF and a weighted variant of spherical k-means, from which we derive our first method, a simple EM-like algorithm. This also allows us to determine when ONMF should be preferred to k-means and spherical k-means. Our second method is based on an augmented Lagrangian approach. Standard ONMF algorithms typically enforce nonnegativity for their iterates while trying to achieve orthogonality at the limit (e.g., using a proper penalization term or a suitably chosen search direction). Our method works the opposite way: orthogonality is strictly imposed at each step while nonnegativity is asymptotically obtained, using a quadratic penalty. Finally, we show that the two proposed approaches compare favorably with standard ONMF algorithms on synthetic, text and image data sets.Comment: 17 pages, 8 figures. New numerical experiments (document and synthetic data sets

Detection of a period decrease in NN Ser with ULTRACAM: evidence for strong magnetic braking or an unseen companion?

We present results of high time resolution photometry of the eclipsing pre-cataclysmic variable NN Ser. We observed 13 primary eclipses of NN Ser using the high-speed CCD camera ULTRACAM and derived times of mid-eclipse, from fitting of light curve models, with uncertainties as low as 0.06 s. The observed rates of period change appear difficult to reconcile with any models of orbital period change. If the observed period change reflects an angular momentum loss, the average loss rate is consistent with the loss rates (via magnetic stellar wind braking) used in standard models of close binary evolution, which were derived from observations of much more massive cool stars. Observations of low-mass stars such as NN Ser's secondary predict rates of ~100 times lower than we observe. We show that magnetic activity-driven changes in the quadrupole moment of the secondary star (Applegate, 1992) fail to explain the period change by an order of magnitude on energetic grounds, but that a light travel time effect caused by the presence of a third body in a long (~ decades) orbit around the binary could account for the observed changes in the timings of NN Ser's mid-eclipses. We conclude that we have either observed a genuine angular momentum loss for NN Ser, in which case our observations pose serious difficulties for the theory of close binary evolution, or we have detected a previously unseen low-mass companion to the binary.Comment: 10 pages, 6 figures. Accepted for publication in MNRA

Melanocortins and agouti-related protein modulate the excitability of two arcuate nucleus neuron populations by alteration of resting potassium conductances

The hypothalamic melanocortin system is crucial for the control of appetite and body weight. Two of the five melanocortin receptors, MC3R and MC4R are involved in hypothalamic control of energy homeostasis, with the MC4R having the major influence. It is generally thought that the main impact of the melanocortin system on hypothalamic circuits is external to the arcuate nucleus, and that any effect locally in the arcuate nucleus is inhibitory on proopiomelanocortin-expressing (POMC) neurons. In contrast, using current- and voltage-clamp recordings from identified neurons, we demonstrate that MC3R and MC4R agonists depolarize arcuate POMC neurons and a separate arcuate neuronal population identified by the rat insulin 2 promoter (RIPCre) transgene expression. Furthermore, the endogenous MC3R and MC4R antagonist, agouti-related protein (AgRP), hyperpolarizes POMC and RIPCre neurons in the absence of melanocortin agonist, consistent with inverse agonism at the MC4R. A decreased transient outward (I(A)) potassium conductance, and to a lesser extent the inward rectifier (K(IR)) conductance, underlies neuronal depolarization, whereas an increase in I(A) mediates AgRP-induced hyperpolarization. Accordingly, POMC and RIPCre neurons may be targets for peptide transmitters that are possibly released locally from AgRP-expressing and POMC neurons in the arcuate nucleus, adding further previously unappreciated complexity to the arcuate system

A solid state fungal fermentation-based strategy for the hydrolysis of wheat straw

This paper reports a solid-state fungal fermentation-based pre-treatment strategy to convert wheat straw into a fermentable hydrolysate. Aspergillus niger was firstly cultured on wheat straw for production of cellulolytic enzymes and then the wheat straw was hydrolyzed by the enzyme solution into a fermentable hydrolysate. The optimum moisture content and three wheat straw modification methods were explored to improve cellulase production. At a moisture content of 89.5%, 10.2 ± 0.13 U/g cellulase activity was obtained using dilute acid modified wheat straw. The addition of yeast extract (0.5% w/v) and minerals significantly improved the cellulase production, to 24.0 ± 1.76 U/g. The hydrolysis of the fermented wheat straw using the fungal culture filtrate or commercial cellulase Ctec2 was performed, resulting in 4.34 and 3.13 g/L glucose respectively. It indicated that the fungal filtrate harvested from the fungal fermentation of wheat straw contained a more suitable enzyme mixture than the commercial cellulase

Chemo-resistant choriocarcinoma metastatic to colon cured by low-anterior resection

The role of surgery in the treatment of patients with metastatic choriocarcinoma has diminished. We present a case of chemo-resistant metastatic choriocarcinoma salvaged by surgery. A 48-year-old patient presented with uterine perforation and severe intractable hemorrhage, and histological examination revealed a choriocarcinoma. After 6 years of disease-free state, recurrence occurred in the rectosigmoid colon. Seven cycles of EMACO chemotherapy was administered, and the human chorionic gonadotropin level was normalized. Three months after the chemotherapy, the rectosigmoid colon metastasis progressed. Low anterior resection with lymphadenectomy up to the level of the inferior mesenteric artery was conducted. After the operation, the human chorionic gonadotropin level decreased to within the normal range. There has been no evidence of disease for 13 months since the operation. Local resection of metastases seems to play a significant role in curing the disease in a small subset of patients

Effect of paternal folate deficiency on placental folate content and folate receptor α expression in rats

We investigated the effect of paternal folate status on folate content and expression of the folate transporter folate receptor α (FRα) in rat placental tissues. Rats were mated after males were fed a diet containing 0 mg of folic acid/kg of diet (paternal folate-deficient, PD) or 8 mg folic acid/kg of diet (paternal folate-supplemented, PS) for 4 weeks. At 20 days of gestation, the litter size, placental weight, and fetal weight were measured, and placental folate content (n = 8/group) and expression of FRα (n = 10/group) were analyzed by microbiological assay and Western blot analysis, respectively. Although there was no difference observed in litter size or fetal weight, but significant reduction (10%) in the weight of the placenta was observed in the PD group compared to that in the PS group. In the PD group, placental folate content was significantly lower (by 35%), whereas FRα expression was higher (by 130%) compared to the PS group. Our results suggest that paternal folate status plays a critical role in regulating placental folate metabolism and transport