Multiple Scale-Free Structures in Complex Ad-Hoc Networks

This paper develops a framework for analyzing and designing dynamic networks comprising different classes of nodes that coexist and interact in one shared environment. We consider {\em ad hoc} (i.e., nodes can leave the network unannounced, and no node has any global knowledge about the class identities of other nodes) {\em preferentially grown networks}, where different classes of nodes are characterized by different sets of local parameters used in the stochastic dynamics that all nodes in the network execute. We show that multiple scale-free structures, one within each class of nodes, and with tunable power-law exponents (as determined by the sets of parameters characterizing each class) emerge naturally in our model. Moreover, the coexistence of the scale-free structures of the different classes of nodes can be captured by succinct phase diagrams, which show a rich set of structures, including stable regions where different classes coexist in heavy-tailed and light-tailed states, and sharp phase transitions. Finally, we show how the dynamics formulated in this paper will serve as an essential part of {\em ad-hoc networking protocols}, which can lead to the formation of robust and efficiently searchable networks (including, the well-known Peer-To-Peer (P2P) networks) even under very dynamic conditions

Experience versus Talent Shapes the Structure of the Web

We use sequential large-scale crawl data to empirically investigate and validate the dynamics that underlie the evolution of the structure of the web. We find that the overall structure of the web is defined by an intricate interplay between experience or entitlement of the pages (as measured by the number of inbound hyperlinks a page already has), inherent talent or fitness of the pages (as measured by the likelihood that someone visiting the page would give a hyperlink to it), and the continual high rates of birth and death of pages on the web. We find that the web is conservative in judging talent and the overall fitness distribution is exponential, showing low variability. The small variance in talent, however, is enough to lead to experience distributions with high variance: The preferential attachment mechanism amplifies these small biases and leads to heavy-tailed power-law (PL) inbound degree distributions over all pages, as well as over pages that are of the same age. The balancing act between experience and talent on the web allows newly introduced pages with novel and interesting content to grow quickly and surpass older pages. In this regard, it is much like what we observe in high-mobility and meritocratic societies: People with entitlement continue to have access to the best resources, but there is just enough screening for fitness that allows for talented winners to emerge and join the ranks of the leaders. Finally, we show that the fitness estimates have potential practical applications in ranking query results

PP-005 Clarithromycin resistance assessment in Helicobacter pylori isolates by using 23S rRNA gene molecular markers

Background: H. pylori is a relatively fastidious and microaerophilic microorganism and therefore standard phenotypic susceptibility tests, even in the hands of experts, are slow and can take at least 10 14 days. Molecular based diagnostic assays by using molecular markers for resistance detection offer an attractive alternative approach to obtain susceptibilities to antibiotics with greater accuracy and speed, and the possibility of a same day result. The aim of this study is the assessment of clarithromycin resistance by using molecular markers. Methods: This cross-sectional descriptive study was performed on 200 gastric biopsy specimens which were obtained from patients undergoing upper gastrointestinal tract endoscopy in Hajar hospital of Shahrekord, by using TaqMan real-time PCR. Initially, H. pylori strains were identified by RUT and PCR. Then, by this regard that accumulation of mutations associated with resistance to clarithromycin were in the region between nucleotides 2142 2144 of 23S rRNA gene, the first probe was designed to be able the distinguish between sensitive and resistant strains. Finally four probes were designed that each be able to identify only one mutation associated with a particular level of clarithromycin resistance. Results: Out of 200 samples, 164 (82%) were H. pylori positive. Overall, clarithromycin susceptible strains were detected in 105 (64.02%) patients and clarithromycin resistance were detected in 59 (35.98%) which were identified as 4 (2.44%) A2144G, 26 (15.85%) A2143G, 15 (9.15%) A2143C and 20 (12.19%) A2142G point mutations. Purely resistant strains were detected in 38 (23.17%), while heteroresistant were found in the remaining 16 (9.76%) cases. Genotype of 5 (8.47%) strains was not detected. This data was confirmed by PCR-RFLP technique. Conclusion: Results showed that Real-time PCR assay in combination with molecular markers has high accuracy to simultaneously identify H. pylori and clarithromycin resistance types directly in gastric biopsy specimens in short time

The prevalence of virulence sodC1 and sopE1 genes among the clinical serotypes of Salmonella enterica in Tehran, Iran

Aims: There is few data on the occurrence of virulence genes in the endemic strains of Salmonella in Iran. This is why the current study has aimed to investigate the presence and the prevalence of sopE1 and sodC1 genes in Salmonella enterica serotypes isolated in Tehran, Iran. Methods: In this descriptive study carried out from December 2008 to November 2010, 95 clinical samples were collected from different hospitals in Tehran. Bacterial isolation and identification was achieved through biochemical and serological methods. The Polymerase Chain Reaction (PCR) technique was used for the detection of sodC1 and sopE1 genes among the Salmonella strains. Results: The frequency of the sodC1 and sopE1 genes were 100% and 95.7% respectively. Serotyping results showed that the most Salmonella isolates belonged to serotypes S. entretidis, S. infantis and S. thyphimurium. Conclusion: For the first time this study reports the presence and prevalence of sopE1 and sodC1 genes in Salmonella enterica strains in Iran. When compared with the other reports from other countries, the frequency of the sopE1 and sodC1 genes in the Salmonella enterica strains isolated from Iran is extremely high

Topological phase transition in a network model with preferential attachment and node removal

Preferential attachment is a popular model of growing networks. We consider a generalized model with random node removal, and a combination of preferential and random attachment. Using a high-degree expansion of the master equation, we identify a topological phase transition depending on the rate of node removal and the relative strength of preferential vs. random attachment, where the degree distribution goes from a power law to one with an exponential tail.Comment: The final publication is available at http://www.epj.or

Intelligent evacuation management systems: A review

Crowd and evacuation management have been active areas of research and study in the recent past. Various developments continue to take place in the process of efficient evacuation of crowds in mass gatherings. This article is intended to provide a review of intelligent evacuation management systems covering the aspects of crowd monitoring, crowd disaster prediction, evacuation modelling, and evacuation path guidelines. Soft computing approaches play a vital role in the design and deployment of intelligent evacuation applications pertaining to crowd control management. While the review deals with video and nonvideo based aspects of crowd monitoring and crowd disaster prediction, evacuation techniques are reviewed via the theme of soft computing, along with a brief review on the evacuation navigation path. We believe that this review will assist researchers in developing reliable automated evacuation systems that will help in ensuring the safety of the evacuees especially during emergency evacuation scenarios

An Ontological Approach to Inform HMI Designs for Minimizing Driver Distractions with ADAS

ADAS (Advanced Driver Assistance Systems) are in-vehicle systems designed to enhance driving safety and efficiency as well as comfort for drivers in the driving process. Recent studies have noticed that when Human Machine Interface (HMI) is not designed properly, an ADAS can cause distraction which would affect its usage and even lead to safety issues. Current understanding of these issues is limited to the context-dependent nature of such systems. This paper reports the development of a holistic conceptualisation of how drivers interact with ADAS and how such interaction could lead to potential distraction. This is done taking an ontological approach to contextualise the potential distraction, driving tasks and user interactions centred on the use of ADAS. Example scenarios are also given to demonstrate how the developed ontology can be used to deduce rules for identifying distraction from ADAS and informing future designs