BGP Anomaly Detection with Balanced Datasets

We use machine learning techniques to build predictive models for anomaly detection in the Border Gateway Protocol (BGP). Imbalanced datasets of network anomalies pose limitations to building predictive models for anomaly detection. In order to achieve better classification performance measures, we use resampling methods to balance classes in the datasets. We use undersampling, oversampling and combination techniques to change class distributions of the datasets. In this paper we build predictive models based on preprocessed network anomaly datasets of known Internet network anomalies and observe improvement in classifier performance measures compared to those reported in our previous work. We propose to use resampling combination techniques on datasets along with Decision Tree and Naïve Bayes classifiers in order to achieve the best trade-off between (1) the F-measure and the length of model training time, and (2) avoiding overfitting and loss of information

Tumor necrosis factor-alfa and interleukin-4 in cerbrospinal fluid and plasma in different clinical forms of multiple sclerosis

Background/Aim. Multiple sclerosis (MS) is an immunemediated central nervous system disease characterized by inflammation, demyelination and axonal degeneration. Cytokines are proven mediators of immunological process in MS. The aim of this study was to investigate whether there is a difference in the production of the tumor necrosis factor alpha (TNF-alpha) and interleukin-4 (IL-4) in cerebrospinal fluid (CSF) and plasma in the MS patients and the controls (other neurological non-inflammatory diseases) and to determine a possible difference in these cytokines in plasma and CSF in different clinical forms of MS. Methods. This study involved 60 consecutive MS patients - 48 patients with relapsing-remitting MS (RRMS) and 12 patients with secondary progressive MS (SPMS). The control group consisted of 20, age and sex matched, nonimmunological, neurological patients. According to the clinical presentation of MS at the time of this investigation, 34 (56.7%) patients had relapse (RRMS), 14 (23.3%) were in remission (RRMS), while the rest of the patients, 12 (20.0%), were SPMS. TNF-alpha and IL-4 concentrations were measured in the same time in CSF and plasma in the MS patients and the controls. Extended disability status score (EDSS), albumin ratio and IgG index were determined in all MS patients. Results. The MS patients had significantly higher CSF and plasma levels of TNF-alpha than the controls (p < 0.001 for both samples). IL-4 CSF levels were significantly lower in the MS patients than in the controls (p < 0.001), however plasma levels were similar. The patients in relapse (RRMS) and with progressive disease (SPMS) had higher concentrations of CSF TNF-alpha levels than the patients in remission (p < 0.001). IL-4 CSF levels in relapse (RRMS) and SPMS groups were lower than in the patients in remission. The patients in remission had an unmeasurable plasma TNF-alpha level and the patients with SPMS had significantly lower IL-4 levels in plasma than the patients in relapse and remission (p < 0.001). The only significant correlation between cytokine level with either EDSS, or albumin ratio, or IgG index, was found between CSF TNF-alpha levels and albumin ratio in the patients with relapse (R square = 0.431, p < 0.001). Conclusion. According to the obtained data MS relapse was characterized by high concentrations of TNF-alpha in CSF and plasma and low concentrations of IL-4 in CSF. Remission was characterized by high concentrations of IL-4 and low concentrations of TNF-alpha both in CSF and plasma. SPMS was characterized with lower concentrations of TNF-alpha and IL-4 compared to relapse, both in CSF and plasma

Dynamics of electrocardiographic changes, brain-natriuretic peptide and cortisol levels in a patient with stress (takotsubo) cardiomyopathy: A case report

Introduction. Takotsubo cardiomyopathy is a transient acute heart failure syndrome caused by stress that provokes left ventricular mid-apical akinesis and mimics acute coronary syndrome. Case report. A 66-year-old woman had chest pain and dispnoea a few hours before hospitalization. A sudden emotional stressful event preceded the symptoms. Electrocardiographic abnormalities - precordial ST elevation and modest increase of cardiac troponin mimiced acute myocardial infarction. However, echocardiographic examination showed apical ballooning with markedly diminished left ventricle ejection fraction and the obstruction in the outflow tract of the left ventricle. Coronary angiography at admission showed no coronary stenosis and slower blood flow through the left anterior descending artery. According to anamnesis, echocardiography and coronarography finding we established the diagnosis of stress cardiomyopathy - takotsubo cardiomyopathy. We described in details the slow but dynamic electrocardiographic changes, levels of brain natriuretic peptide, cortisol and echocardiography evolution of disease during a 4-month follow-up till the full recovery. Conclusion. Stress (takotsubo) cardiomyopathy - became an important differential diagnosis of acute anterior myocardial infarction and it should be reconsidered every time when emotionally stressed patients with transient-apical akinesis or dyskinesis of the LV are present

Concave Pyramids of Second Sort -The Occurrence, Types, Variations

Correspondingly to the method of generating the Concave Cupolae of second sort, the Concave Pyramids of second sort have the similar logic of origination, and their counterpart in regular faced convex pyramids (tetrahedron, Johnson's solids J1 and J2). The difference is that instead of onefold series of equilateral triangles in the lateral surface of the solid, there appear twofold series, forming deltahedral lateral surface with a common point, while bases are also regular polygons. This time, instead of the bases from n=3 to n=5, there are the basis from n=6 to n=9. The same lateral surface’s net can be folded and creased in two different ways, which produces the two types of Concave Pyramids of second sort: with a major and with a minor solid height. Combining and joining so obtained solids by the correspondent bases, the concave (ortho) bipyramids of second sort emerge, which then may be elongated, gyroelongated, and conca-elongated, creating a distinctive family of diverse concave polyhedral structures

The Structural Transformation of Concave Cupolae of Fourth Sort Using Different Variants of Constructive Procedure, 4th International Scientific Conference on Geometry and Graphics

Concave Cupolae of fourth sort (CC IV) are polyhedra which lateral surface is created by folding a quadruple strip of equilateral triangles, while the bases are regular polygons. The unit cell that forms the deltahedral lateral surface by radial sequenceing around the axis of the solid is composed of two spatial hexahedrals. These unit cells are linked together in its upper zone by spatial quadrihedals, which consist of four equilateral triangles grouped around a common vertex. Over the same polygonal base, there can be formed four diverse Concave Cupolae of IV sort, using different variants of constructive procedure. In this paper, the application of the program for modeling the lateral surface of concave cupolae of IV sort, using the software package MATLAB, allows visual monitoring of the structural transformation of the concave cupolae of IV sort, for different polygonal bases and different variants of constructive procedure

Prevođenje konkavnih kupola druge vrste u tridimenzionalne konstruktivne sisteme – prostorne rešetke

Cilj istraživanja ovog rada je bio da se iznađu geometrijska rešenja za formiranje prostornih rešetki nad pravilnim poligonalnim osnovama, tako da se postigne prostorna struktura koja ispunjava zahteve rigidnosti datog sklopa, po osnovi geometrijske stabilnosti trougla kao ravne figure. Takođe, težnja je bila i da se nađe što jednostavnije rešenje, sa upotrebom minimalnog broja različitih štapova u samoj konfiguraciji prostorne rešetke. U tom smislu, moguće je primeniti nekoliko varijanti rasporeda štapova. Najekonomičnije od njih se svodi upravo na geometriju konkavnih kupola druge vrste, buduci da se radi o jednakoivičnim poliedrima kao osnovama za dalju nadogradnju tridimenzionalnih stuktura. Omotač konkavnih kupola druge vrste nastaje nabiranjem ravne mreže, a prevođenjem ivica ovog omotača u sistem štapova, uz dodavanje minimalnog broja različitih tipskih štapova razupirača, dobijamo strukturu kompozitnog poliedra prostorne rešetke.The aim of this paper is to find geometric solutions for the formation of space frames over regular polygonal bases, so to achieve a spatial structure that meets the rigidity requirements of a given assembly, based on the geometric stability of a triangle as a flat figure. Also, the aim is to find the simplest possible solution, with the use of a minimum number of different struts in the configuration of the space frame. In that sense, it is possible to apply several variants of strut arrangement. The most material-efficient of them comes down to the geometry of concave cupolae of the second sort, since they are polyhedra of all the edges of the same length, as a basis for further upgrading of three-dimensional structures. The lateral surface of a concave cupola of the second sort is created by folding its triangular planar net, and by transposing the edges of this surface into a system of struts, having the minimum number of different type struts, we obtain the structure of a composite polyhedron in the role of a space frame.http://mongeometrija.com/zbornici/2008/262-marija-obradovi-slobodan-mii-prevoenje-konkavnih-kupola-druge-vrste-u-tridimenzionalne-konstruktivne-sisteme--prostorne-reetk

Konstruktivna obrada hiperboličke spirale kao centralne projekcije cilindrične zavojnice

Centralna projekcija cilindrične zavojnice jeste ravna transcedentna kriva, u najopštijem slučaju. U određenim slučajevima, ta kriva će biti upravo spiralna kriva. U specijalnom slučaju, kada se osovina cilindra poklapa sa glavnim očnim zrakom, ortogonalnim na likoravan, ova će spirala biti hiperbolička, budući da će imati beskonačno daleku tačku, pridruženu tački prodora zavojnice kroz očnu frontalnicu (Fs). Pravac određen ovom prodornom tačkom kroz Fs određuje asimptotu hiperboličke spirale. U radu su dati konstruktivni postupci za grafičko prikazivanje ove spirale.http://mongeometrija.com/zbornici/2006/337-obradovi-mii-konstruktivna-obrada-hiperbolike-spirale-kao-centralne-projekcije-cilindrine-zavojnic