Predicting Community Evolution in Social Networks

Nowadays, sustained development of different social media can be observed worldwide. One of the relevant research domains intensively explored recently is analysis of social communities existing in social media as well as prediction of their future evolution taking into account collected historical evolution chains. These evolution chains proposed in the paper contain group states in the previous time frames and its historical transitions that were identified using one out of two methods: Stable Group Changes Identification (SGCI) and Group Evolution Discovery (GED). Based on the observed evolution chains of various length, structural network features are extracted, validated and selected as well as used to learn classification models. The experimental studies were performed on three real datasets with different profile: DBLP, Facebook and Polish blogosphere. The process of group prediction was analysed with respect to different classifiers as well as various descriptive feature sets extracted from evolution chains of different length. The results revealed that, in general, the longer evolution chains the better predictive abilities of the classification models. However, chains of length 3 to 7 enabled the GED-based method to almost reach its maximum possible prediction quality. For SGCI, this value was at the level of 3 to 5 last periods.Comment: Entropy 2015, 17, 1-x manuscripts; doi:10.3390/e170x000x 46 page

Identification of Group Changes in Blogosphere

The paper addresses a problem of change identification in social group evolution. A new SGCI method for discovering of stable groups was proposed and compared with existing GED method. The experimental studies on a Polish blogosphere service revealed that both methods are able to identify similar evolution events even though both use different concepts. Some differences were demonstrated as wellComment: The 2012 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining, IEEE Computer Society, 2012, pp. 1233-123

Trusted CI Experiences in Cybersecurity and Service to Open Science

This article describes experiences and lessons learned from the Trusted CI project, funded by the US National Science Foundation to serve the community as the NSF Cybersecurity Center of Excellence. Trusted CI is an effort to address cybersecurity for the open science community through a single organization that provides leadership, training, consulting, and knowledge to that community. The article describes the experiences and lessons learned of Trusted CI regarding both cybersecurity for open science and managing the process of providing centralized services to a broad and diverse community.Comment: 8 pages, PEARC '19: Practice and Experience in Advanced Research Computing, July 28-August 1, 2019, Chicago, IL, US

Analysis of roles and groups in blogosphere

In the paper different roles of users in social media, taking into consideration their strength of influence and different degrees of cooperativeness, are introduced. Such identified roles are used for the analysis of characteristics of groups of strongly connected entities. The different classes of groups, considering the distribution of roles of users belonging to them, are presented and discussed.Comment: 8th International Conference on Computer Recognition Systems, CORES 201

Development Of Spheroidal Graphite Cast Iron For Nuclear Fuel Transport Cask

In the present work SG iron specimens with carbon equivalent (%CE) ranging from 4.12 - 4.36, has been subjected to annealing, normalizing, quench & tempering, austempering and DMS treatment to obtain different matrix microstructure and microconstituent. Optical microscopy is observed for microstructure, phase volume fraction, nodularity, and nodule count for each of the as-cast and heat treat specimens. XRD analysis is done to validate the phases present in each specimen as well as to determine the amount of carbon dissolution in respective phases. Mechanical properties such as tensile strength, % elongation, Vicker’s hardness, and impact strength are measured by conducting necessary test following ASTM standards. Failure mechanisms involved in static and dynamic loading are investigated observing the fracture surfaces after tensile and impact test respectively, under Scanning Electron Microscope. The corrosion behavior of as-cast and heat treated specimens, (in sea water) is also studied. Specimens are immersed completely in sea water at room temperature and pressure, and the weight difference is recorded at regular intervals, for twelve weeks. The mechanical properties showed a quite good relationship with microconstituents for respective as-cast and heat treated specimens. The as-cast specimens show graphite spheroids within ferritic matrix resulted in increased ductility and impact strength (with increasing ferrite volume fraction) caused by increasing Si content. Annealing treatment led to the presence of completely ferritic matrix for every alloy consequently increasing ductility and impact toughness as compared to as-cast matrices. On the other hand specimens which underwent quenching & tempering treatment show the highest strength and hardness due to the tempered martensitic matrix, among all other heat treatment processes. Strength and ductility values of normalized austempered and DMS-treated specimens are intermediate to those of lowest strength value for annealed specimen and higher elongation value and that of highest strength and lowest elongation value for the quenched & tempered specimens. It is observed that the elongation increases with increased nodularity can be attributed to increases amount of Mg and Ce, whereas nodule count increases the hardness of respective as-cast and heat treated specimens. The increase of hardness may be due to increase of Ni and Cr content which provides strength to ferrite via solid solution strengthening (for ferritic specimens). Normalizing treatment produced a ferritic/pearlitic matrix and showed increased UTS and hardness with increased pearlite content. Austempered heat treatment resulted in coarse upper bainitic matrix leading to suitable combination of strength and ductility, whereas matrix consists of martensite and ferrite are obtained by DMS treatment. The failure mode for the soft ferritic matrix is observed to be ductile in nature caused by microvoid coalescence, and that of other matrices are mostly brittle signified by the presence of low energy stress paths (River marking) and cleavage facets. Mechanical properties of SG iron alloys studied in current research, found to be well above the recommended properties for fabrication of nuclear fuel cask, (in as-cast as well as heat treated conditions) and hence can successfully be used for the desired purpose

Different Approaches to Community Evolution Prediction in Blogosphere

Predicting the future direction of community evolution is a problem with high theoretical and practical significance. It allows to determine which characteristics describing communities have importance from the point of view of their future behaviour. Knowledge about the probable future career of the community aids in the decision concerning investing in contact with members of a given community and carrying out actions to achieve a key position in it. It also allows to determine effective ways of forming opinions or to protect group participants against such activities. In the paper, a new approach to group identification and prediction of future events is presented together with the comparison to existing method. Performed experiments prove a high quality of prediction results. Comparison to previous studies shows that using many measures to describe the group profile, and in consequence as a classifier input, can improve predictions.Comment: SNAA2013 at ASONAM2013 IEEE Computer Societ

Proteolízis az idegrendszerben: a humán agyi tripszin szerkezetének és funkciójának vizsgálata = Proteolysis in central nervous system: investigations of the structure and function of human brain trypsin

Klónoztunk a humán tripszinogén 4 teljes kódoló szekvenciáját. Bakterális expressziós rendszerben kifejeztük a két alternatív iniciációval keletkező izoformáját. Expresszáltuk és enzimatikusan karakterizáltuk az a tripszin 4-et. Meghatároztuk az aktív enzim benzamidin komplexének térszerkezetét. Feltérképeztük a mRNS és a fehérje eloszlását a humán agy 17 különböző régiójában. Vizsgáltuk az agyban előforduló potenciális szubsztrátjait. Megállapítottuk, hogy számos, a citoszkeletális váz felépítésében és regulálásában szereplő fehérje és a mielin bázikus fehérje szubsztrátja lehet a tripszin 4-nek. Izoláltuk a tripszinogén 4-et emberi agyszövetből és meghatároztuk amino terminális szekvenciáját. Tranziens szövettenyészetben megfelelően tervezett expressziós vektorok segítségével megállapítottuk, hogy az amino terminális leucin beépülését nem-konvencionális CTG iniciátor kodon irányítja. Meghatároztuk a tripszin - metilubellireril guanidinobenzoáttal történő reakciójának elemi sebességi állandóit. Vizsgáltuk számos természetes és szintetikus inhibitor gátló képességét, és valószínű magyarázatot adtunk arra, miért lehetetlen kanonikus mechanizmus alapján gátolni a tripszin 4-et. | We have isolated the complete coding sequence of human trypsinogen 4. In bacterial expression system we expressed and purified the two putative isoforms of the enzyme. We isolated the active enzyme as well, and characterized its enzymatic properties. We determined the X-ray structure of the trypsin 4 ? benzamidine complex. By quantitative real time PCR and sandwich ELISA we determined the determined the distribution of the mRNA and protein in 17 different regions of the human brain. By sequencing the zymogen isolated from human brain we concluded that predominant form in the human brain possesses leucine amino terminus. Using human tissue cultures transiently transfected with appropriately designed expression vectors we proved that the incorporation of the amino terminal leucine is directed by a non-conventional CTG initiation codon. We determined the elementary kinetic constants of the trypsin 4 - methylumbelliferyl guanidine benzoate reaction. We studied the inhibitory potential of several natural and synthetic polypeptides, and we reasoned why is it impossible to inhibit trypsin 4 by a canonical inhibitor

Application of Different Heat Treatment to Spheroidal Graphite Cast Iron and its Effect for Damping and Mode Shapes

In this study, damping and mode shapes were investigated after boriding and austempering the spheroidal graphite cast iron (SGCI). The samples were boronised and austempered at 900℃ for 2 hours by employing the pack cementation method. The samples were cooled and tempered in a salt bath at 250℃ and 375℃ for 1 hour. Once the boriding and austempering processes were completed, the samples were cooled at room temperature and washed with plenty of water. The modal frequencies, damping ratios and mode shapes of these samples exposed to different heat treatments were acquired by using the experimental modal analysis (MA) method. The same characteristic features were acquired with the finite element method (FEM), and the results were compared. It was found that after the heat treatment the sample austempered at 250oC had a harder surface and a higher frequency than other samples