124 research outputs found

    BGP Anomaly Detection with Balanced Datasets

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    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

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    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

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    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

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    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

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    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

    Pentagon-Based Radial Tiling with Triangles and Rectangles and Its Spatial Interpretation

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    The paper considers a type of radial pentagon-based tiling consisting of two shapes: triangle and rectangle. The ob tained solution has a spatial interpretation in a 3D arrangement of equilateral triangles and squares dictated by the particular array of concave cupolae of the second sort, minor type (CC-II 5.m). These cupolae are arranged so that their decagonal bases partly overlap, making a pentagonal pattern (similar to the one of the Penrose tiling). Covering the folds between the faces of such a polyhedral structure with polygons, we use exactly equi lateral triangles and squares, thanks to the trigonometric prop erties of CC-II-5.m. Observed in the orthogonal projection onto the plane of the polygonal bases, this 3D “covering” is viewed as a pentagonal-based radial tiling in the Euclidean plane. Equilateral triangles will be projected into congruent isosceles triangles corresponding to those obtained by the radial sec tion of a regular pentagon in 5 parts. The squares are project ed into rectangles whose ratio is: a:b = 1:φ/√(1+φ2), where φ is the golden ratio. These triangles and rectangles form a ra dial tiling consisting of 5 sectors of the plane, where the pat terns of the established tiles are repeated locally periodically. However, with 5-fold rotation of the pattern, the tiling itself is non-periodic. The various tiling solutions that can be obtained in this way may serve as inspiration for the geometric design, especially interesting in architecture and applied arts, e.g. for rosettes, brise soleils, mosaics, stained glass, fences, partition screens and the likehttps://smartart-conference.rs/sr/%d1%82%d0%b5%d0%bc%d0%b0%d1%82%d1%81%d0%ba%d0%b8-%d0%b7%d0%b1%d0%be%d1%80%d0%bd%d0%b8%d0%ba-2021/ http://doi.fil.bg.ac.rs/pdf/eb_ser/smartart/2022-2/smartart-2022-2-ch19.pd

    Evaluation of the therapeutic effect of hyperbaric oxygenation and erythropoietin in the treatment of chronic heart failure using myocardial perfusion scintigraphy G-SPECT

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    Background. The most important predictors of longterm survival in patients with cardiac ischemic disease are left ventricular ejection fraction, left ventricular volumes, infarction size, presence and extent of residual myocardial ischemia. One of the most important recent developments in single photon emission computed tomography (SPECT) myocardial perfusion imaging is the ability to acquire these studies in conjunction with electrocardiogram (ECG) gating (G-SPECT). The ability to asses radionuclide myocardial perfusion and function with ECG G-SPECT imaging has revolutionized this field of nuclear cardiology. Study with G-SPECT development algorithms permits to quantify measures of left ventricular (LV) volume, ejection fraction (LVEF) and even regional myocardial wall motion and thickening. The American Society of Nuclear Cardiology (ASNC) in its position paper from March 1999 recommends the routine incorporation of G-SPECT during cardiac perfusion scintigraphy. Case report. We presented a 70-year-old male with ischemic heart disease (dilatative, cardiomyopathy and absolute arrhythmia). He was few times hospitally treated by medicamentous therapy with no evidence of improvement. After hospital treatment, we included hyperbaric oxygenation (HBO) and erythropoietin injections. Hyperbaric oxygenation was carried out in a monoplace hyperbaric chamber, BLK S-303, by a graduated protocol for patients with severe heart insufficiency, totally 15 treatments. Recombinant erythropoietin beta (RecormonR F. Hoffmann-La Roche) was applied deeply subcutaneously, every second day from 2 000 IU to totally 16 000 IU. Before the therapy G-SPECT study was performed with 99m technetium-MIBI, and we obtained the functional parameters and perfusion of the left ventricle to follow-up the therapy effects. The study was performed by an ADAC-VERTEX PLUS-EPIC two-head gamma camera with dedicated quantitatively algorithm Auto-QUANT. The results of LVEF were 15%, with severity abnormal motion and wall thickening for all segments. Left ventricle end-diastolic volume was 393 ml (normal < 142 ml), and LV end-systolic volume was 334 ml (normal < 65 ml). Four months after the therapy G-SPECT showed improvement in any parameters; LVEF 25%, with improvement in wall motion (normalized wall motion in the anterior, lateral area, and proximal septum) and wall thickening, LV end-diastolic volume was 390 ml, LV end-systolic volume was 289 ml. Conclusion. Using G-SPECT method before and after the therapy with hyperbaric oxygenation and erythopoietine we obtained objective improvement and good therapy effects in the treatment of chronic heart insufficiency

    Learning while playing - Througie platform for creating models of spatial structures

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    The paper shows a way to create a set of tools that allows the construction of different models of spatial deltahedral structures as a result of the game. It is a set of accessories with which participants (school children, students) through play, experimenting with different layouts and combinations of elements of the whole, create spatial forms from uniform elements: sticks of length "a" and ringshaped joint connections. The game uses a STEM learning approach and the "learning by doing" method to provide knowledge about the spatial relationships of elements and static properties of the structure, in the process of playing. The process of forming structures via mentioned connecting elements uses the same principle of connecting supports and nodes as in the real space truss. A similar method is used by some other gaming platforms, such as Geomag, Magna-tiles, Picasso, or Blockaroo. Unlike them, our solution does not use magnets, but prestressing.https://mongeometrija2023.ftn.uns.ac.rs/?page_id=1
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