Poisson factorization for peer-based anomaly detection

Anomaly detection systems are a promising tool to identify compromised user credentials and malicious insiders in enterprise networks. Most existing approaches for modelling user behaviour rely on either independent observations for each user or on pre-defined user peer groups. A method is proposed based on recommender system algorithms to learn overlapping user peer groups and to use this learned structure to detect anomalous activity. Results analysing the authentication and process-running activities of thousands of users show that the proposed method can detect compromised user accounts during a red team exercise

Invoice from J. M. Heard to Ogden Goelet

https://digitalcommons.salve.edu/goelet-personal-expenses/1025/thumbnail.jp

Receipt from J. M. Heard to Ogden Goelet

https://digitalcommons.salve.edu/ochre-court/1215/thumbnail.jp

Keyed Non-Parametric Hypothesis Tests

The recent popularity of machine learning calls for a deeper understanding of AI security. Amongst the numerous AI threats published so far, poisoning attacks currently attract considerable attention. In a poisoning attack the opponent partially tampers the dataset used for learning to mislead the classifier during the testing phase. This paper proposes a new protection strategy against poisoning attacks. The technique relies on a new primitive called keyed non-parametric hypothesis tests allowing to evaluate under adversarial conditions the training input's conformance with a previously learned distribution $\mathfrak{D}$. To do so we use a secret key $\kappa$ unknown to the opponent. Keyed non-parametric hypothesis tests differs from classical tests in that the secrecy of $\kappa$ prevents the opponent from misleading the keyed test into concluding that a (significantly) tampered dataset belongs to $\mathfrak{D}$.Comment: Paper published in NSS 201

Phosphorus and zinc fertilization: beneficial management practices for corn in Manitoba

Non-Peer ReviewedYear 1 and 2 results of a research project are presented for two P fertilization studies, one with crop rotation and the other with residue management. The objectives of the two studies were to evaluate i) corn response to spring side-banded P and Zn fertilizer when corn follows canola versus soybeans, ii) corn response to fall banded and spring side-banded P fertilizer in strip tillage and conventional tillage. Each study was established at two locations in 2014 and 2015 with canola and soybeans grown as preceding crops for the rotation study, and fall conventional and strip tillage for the residue management study. The rotation study included a control (no P) and two rates of P (27 and 54 lb P2O5/ac) in the form of monoammonium phosphate (MAP) (11-54-0) or Microessentials MESZn (12-40-0-10-1) side-banded (2” to the side and 1” below the seed) during corn planting in the spring of 2015 and 2016. The residue management study treatments included a control (no P), two rates of P (27 and 54 lb P2O5/ac) in the form of MAP, applied either in the fall as a deep band (4 – 5”) with the strip till unit or in the spring as a side-band with the corn planter. Preliminary results for the rotation study showed a substantial early season vegetative response to all fertilizer P treatments, resulting in an 85-110% increase in biomass compared to the control, especially in corn following canola. Silking date was advanced by 3-7 days with application of starter P. At harvest, all starter P treatments reduced kernel moisture by 2-3% in corn following canola only, and there was a 10% yield increase in grain yield with the high rate of MAP compared to the control, regardless of preceding crop. Preliminary results for the residue management study showed that spring side-banded P treatments increased early season biomass by 77-81% and silking date was advanced by 3 days at 2 site-years, compared to the control. At harvest, fertilizer P reduced kernel moisture by 1-2% at both sites in 2016, and spring side-banded P out-yielded the control and fall applied treatments by 5%, regardless of tillage system

Tricarbonylrhenium(I) halide complexes of chiral non-racemic 2-(dioxolanyl)-(dioxanyl)pyridine ligands: synthesis, NMR and DFT calculations.

The chiral non-racemic O/N/O donor ligands 2-[(4R,5R)-4,5-dimethyl-1,3-dioxolan-2-yl]-6-[(4R,6R)-4,6-dimethyl-1,3-dioxan-2-yl]pyridine and 2-[(4R,5R)-4,5-dimethyl-1,3-dioxolan-2-deuteryl]-6-[(4R,6R)-4,6-dimethyl-1,3-dioxan-2-yl]pyridine were prepared in a stepwise fashion form 2,6-dibromopyridine. Reaction with the pentacarbonylhalogenorhenium(I) compounds yields the complexes [ReX(CO)3L], in which the ligands act in a N/O bidentate chelate fashion. There are eight possible diastereoisomers, three of which are observable in solution. DFT calculations indicate that the relative stability of the diastereoisomers is SR5>RR5>SS5≈RS5>RS6>SS6>RR6>SR6. Above ambient temperature, a dynamic process leads to the exchange of 2 of the 3 diastereoisomers: the free energy of activation is ca. 79 kJ mol−1. The results of the DFT calculations and the magnitude of ΔG‡ suggest the dynamic process to be the flip of the co-ordinated acetal ring. DFT calculations on the [ReX(CO)3] complexes of chiral non-racemic 2-(dioxolanyl)-6-(dioxanyl)pyridines, in which the ligands coordinate in a bidentate N/O fashion, indicate that binding of the five-membered dioxolanyl ring is strongly favoured over that of the six-membered dioxanyl ring. In solution 3 of the 8 possible diastereoisomers are observed, two of which undergo exchange above ambient temperature

Potentiated virucidal activity of pomegranate rind extract (PRE) and punicalagin against Herpes simplex virus (HSV) when co-administered with zinc (II) ions, and antiviral activity of PRE against HSV and aciclovir-resistant HSV

Background There is a clinical need for new therapeutic products against Herpes simplex virus (HSV). The pomegranate, fruit of the tree Punica granatum L, has since ancient times been linked to activity against infection. This work probed the activity of pomegranate rind extract (PRE) and co-administered zinc (II) ions. Materials and methods PRE was used in conjunction with zinc (II) salts to challenge HSV-1 and aciclovir-resistant HSV in terms of virucidal plaque assay reduction and antiviral activities in epithelial Vero host cells. Cytotoxicity was determined by the MTS assay using a commercial kit. Results Zinc sulphate, zinc citrate, zinc stearate and zinc gluconate demonstrated similar potentiated virucidal activity with PRE against HSV-1 by up to 4-fold. A generally parabolic relationship was observed when HSV-1 was challenged with PRE and varying concentrations of ZnSO4, with a maximum potentiation factor of 5.5. Punicalagin had 8-fold greater virucidal activity than an equivalent mass of PRE. However, antiviral data showed that punicalagin had significantly lower antiviral activity compared to the activity of PRE (EC50 = 0.56 μg mL-1) a value comparable to aciclovir (EC50 = 0.18 μg mL-1); however, PRE also demonstrated potency against aciclovir-resistant HSV (EC50 = 0.02 μg mL-1), whereas aciclovir showed no activity. Antiviral action of PRE was not influenced by ZnSO4. No cytotoxicity was detected with any test solution. Conclusions The potentiated virucidal activity of PRE by coadministered zinc (II) has potential as a multi-action novel topical therapeutic agent against HSV infections, such as coldsores

Topical delivery of a Rho-kinase inhibitor to the cornea via mucoadhesive film

The application of inhibitors of the Rho kinase pathway (ROCK inhibitors) to the surface of the eye in the form of eyedrops has beneficial effects which aid the recovery of diseased or injured endothelial cells that line the inner surface of the cornea. The aim of this study was to test the plausibility of delivering a selective ROCK inhibitor, Y-27,632, to the cornea using a thin polymeric film. Mucoadhesive polymeric thin films were prepared incorporating Y-27,632 and diffusional release into PBS was determined. Topical ocular delivery from the applied film was investigated using freshly excised porcine eyes and eyedrops of equivalent concentration acted as comparators; after 24 h the formulations were removed and the corneas extracted. Drug-loaded thin polymeric films, with high clarity and pliability were produced. ROCK inhibitor Y-27,632 was weakly retained within the film, with release attaining equilibrium after 1 h. This in turn facilitated its rapid ocular delivery, and an approximately three-fold greater penetration of Y-27,632 into cryoprobe-treated corneas was observed from the thin film (p < 0.01) compared to eyedrop. These findings support the further development of ROCK inhibitor delivery to the cornea via release from thin mucoadhesive films to treat vision loss cause by corneal endothelial dysfunction

Changepoint detection on a graph of time series

When analysing multiple time series that may be subject to changepoints, it is sometimes possible to specify a priori, by means of a graph G, which pairs of time series are likely to be impacted by simultaneous changepoints. This article proposes a novel Bayesian changepoint model for multiple time series that borrows strength across clusters of connected time series in G to detect weak signals for synchronous changepoints. The graphical changepoint model is further extended to allow dependence between nearby but not necessarily synchronous changepoints across neighbour time series in G. A novel reversible jump MCMC algorithm making use of auxiliary variables is proposed to sample from the graphical changepoint model. The merit of the proposed model is demonstrated via a changepoint analysis of real network authentication data from Los Alamos National Laboratory (LANL), with some success at detecting weak signals for network intrusions across users that are linked by network connectivity, whilst limiting the number of false alerts.Comment: 31 pages, 13 figure