Detecting and classifying delay Data Exceptions on communication networks using rule based algorithms

Network performance monitoring is essential for managing a network efficiently and for ensuring reliable operation of the network. Monitored network performance changes reflect events in the network, such as faults, significant changes in usage patterns or planned alterations. Network managers are interested in how and when the performance of a network changes; however it is inefficient to analyse all the data resulting from the monitoring operation manually. In this paper a rule based algorithm to automate detection of the changes in one of the network performance parameters, namely delay, is presented and described in detail. The nature of the delay pattern in a commercial communication network was the key issue in developing this algorithm. The approach was tested with monitored delay data generated from three different networks and showed good results. Also, the algorithm was tested with sets of delay data which have been already input to a previously developed detector based on a different approach, and the results between the two detectors are compared. In addition to a noticeable improvement in detection performance, the new approach provides more generality and independency of the source of the delay data, making the approach generally applicable to other networks. Copyright © 2004 John Wiley & Sons, Ltd.     

Macroblock Level Bits Allocation for Depth Maps in 3-D Video Coding

For 3-D videos, one commonly used representation method is texture videos plus depth maps for several selected viewpoints, whereas the other viewpoints are synthesized based on the available texture videos and depth maps with the depth-image-based rendering (DIBR) technique. As both the quality of the texture videos and depth maps will affect the quality of the synthesized views, bits allocation for the depth maps become indispensable. The existing bits allocation approaches are either inaccurate or requiring pre-encoding and analyzing in temporal dimension, making them unsuitable for the real-time applications. Motivated by the fact that different regions of the depth maps have different impacts on the synthesized image quality, a real-time macroblock level bits allocation approach is proposed, where different macroblocks of the depth maps are encoded with different quantization parameters and coding modes. As the bits allocation granularity is fine, the R-D performance of the proposed approach outperforms other bits allocation approaches significantly, while no additional pre-encoding delay is caused. Specifically, it can save more than 10% overall bit rate comparing with Morvan’s full search approach, while maintaining the same synthesized view quality.     

Theoretical study of the circuit architecture of the basic CFOA and testing techniques

This paper examines the closed-loop characteristics of the basic Current-Feedback Operational Amplifier (CFOA), and in particular, the dynamic response. Additionally, it also examines the design and advantages of the CFOA regarding its ability to provide a significantly constant closed-loop bandwidth for closed-loop voltage gain. Secondly, the almost limitless slew–rate provided by the class AB input stage that makes it superior to the voltage-mode operational amplifier (VOA) counterpart. Additionally, this paper also concerns the definitions and measurements of the terminal parameters of the CFOA, regarded as a ‘black box’. It does not deal with the way that these parameters are related to the properties of the active passive and active components of a particular circuit configuration. Simulation is used in terminal parameter determination: this brings with it the facility of using test conditions that would not normally prevail in a laboratory test on silicon implementations of the CFOAs. Thus, we can apply 1mA and 1mV test signals from, respectively, infinite and zero source impedances that range in frequency from d.c to some tens of GHz. Also, we assume the existence of resistors with identical Ohmic value and very high value ideal capacitors. Where appropriate, practical test methods are referred to physical laboratory prototypes.     

Nickel oxide nanoparticles grown on mesoporous carbon as an efficient electrocatalyst for urea electro-oxidation

Nickel oxide nanoparticles were formed on mesoporous carbon (NiO/MC) through precipitating nickel hydroxide species followed by post annealing treatment. The as-prepared electrocatalysts were physically characterized using XRD, Raman, EDX, SEM, TEM and HRTEM analysis techniques. Very fine nanoparticles were shown in TEM image and their chemical identity was proved in XRD pattern by three crystal indices of nickel oxide species as (111), (200) and (220). The electrocatalytic activity of NiO/MC electrocatalysts was investigated for oxidizing urea molecules in 0.5 M NaOH solution. Adding variable nickel oxide loading values during the electrocatalyst preparation method appreciably affected the obtained oxidation current density. Increasing the deposited oxide weight percentage would enhance the activity of formed nanocomposite to attain its optimum performance at the electrocatalyst containing 17.5 wt% NiO. The effect of altering urea concentration and scan rate during the oxidation process on the resultant electrocatalyst activity was studied. Chronoamperograms displayed improved steady state oxidation current density values after 1800 s revealing stable nanocatalysts. This promising electrocatalytic behavior of NiO/MC elects its application as an active component for urea electro-oxidation in many potential applications including hydrogen production, fuel cells and water purification.     

Generation and Selection of Specific Aptamers Targeting Brucella Species through an Enhanced Cell-SELEX Methodology

Brucellae are Gram-negative, aerobic, non-motile coccobacilli causing brucellosis in man and animals. The disease is one of the most significant yet neglected global zoonoses. Especially in developing countries, brucellosis is causing public health problems and economic losses to private animal owners and national revenues. Composed of oligonucleotides, aptamers are chemical analogues of antibodies that are promising components for developing aptamer-based rapid, sensitive, and specific tests to identify the Brucella group of bacteria. For this purpose, aptamers were generated and selected by an enhanced protocol of cell systematic evolution of ligands by exponential enrichment (cell-SELEX). This enhanced cell-SELEX procedure involved the combination of both conventional and toggle cell-SELEX to boost the specificity and binding affinity to whole Brucella cells. This procedure, combined with high-throughput sequencing of the resulting aptamer pools, comprehensive bioinformatics analysis, and wet lab validation assays, led to the selection of a highly sensitive and specific aptamer for those Brucella species known to circulate in Egypt. The isolated candidate aptamer showed dissociation constant (K_D) values of 43.5 ± 11, 61.5 ± 8, and 56 ± 10.8 nM for B. melitensis, B. abortus, and B. suis, respectively. This is the first development of a Brucella-specific aptamer using an enhanced combination of conventional and toggle cell-SELEX to the authors’ best knowledge.     

Hybrid model of clustering and kernel autoassociator for reliable vehicle type classification

Automatic vehicle classification is an important area of research for intelligent transportation, traffic surveillance and security. A working image-based vehicle classification system is proposed in this paper. The first component vehicle detection is implemented by applying histogram of oriented gradient features and SVM classifier. The second component vehicle classification, which is the emphasis of this paper, is accomplished by a hybrid model composed of clustering and kernel autoassociator (KAA). The KAA model is a generalization of auto-associative networks by training to recall the inputs through kernel subspace. As an effective one-class classification strategy, KAA has been proposed to implement classification with rejection, showing balanced error–rejection trade-off. With a large number of training samples, however, the training of KAA becomes problematic due to the difficulties involved with directly creating the kernel matrix. As a solution, a hybrid model consisting of self-organizing map (SOM) and KAM has been proposed to first acquire prototypes and then construct the KAA model, which has been proven efficient in internet intrusion detection. The hybrid model is further studied in this paper, with several clustering algorithms compared, including k-mean clustering, SOM and Neural Gas. Experimental results using more than 2,500 images from four types of vehicles (bus, light truck, car and van) demonstrated the effectiveness of the hybrid model. The proposed scheme offers a performance of accuracy over $95~\%$ with a rejection rate $8~\%$ and reliability over $98~\%$ with a rejection rate of $20~\%$ . This exhibits promising potentials for real-world applications.     

Seismic vulnerability of historical masonry buildings for different earthquake characteristics: Case study of the mosque of Takiyya al‐Sulaymaniyya

Different factors influence the collapse behaviour of masonry structures, and one of the major factors is the characteristics of the earthquake itself. This effect is going to be more complicated for historical constructions, which involve different structure members of different geometries. The present study focuses on the effect of earthquake characteristics on the collapse behaviour of historical masonry structures. The effect of earthquake direction and the frequency content of the earthquake are mainly considered. A brief background of the selected case study and modelling process are presented. The geometry of the whole structure is created using micro modelling strategy. The collapse analysis of the structure is performed under artificial model based on the earthquake characteristics. Unidirectional earthquake are applied to the structure from different angels in order to investigate the weakest situation. Finally, different earthquake models are generated with different frequency contents according the soil profiles and applied consequently on the structure to explore the worst situation. Seismische Gefährdung von historischen Mauerwerksbauten infolge Erdbebeneinwirkung — Fallstudie: Die Moschee von Takiyya al‐Sulaymaniyya. Verschiedene Faktoren beeinflussen das Versagen von Mauerwerksstrukturen. Ein wesentlicher ist die Erdbebeneinwirkung selbst. Deren Charakteristik und Auswirkung ist für historische Konstruktionen, welche aufgrund der verschiedenen verwendeten und zusammenwirkenden Tragelemente und der großen Bandbreite geometrischer Formen eine komplexe Versagensabhängigkeit aufweisen, noch schwieriger einzuschätzen. Die in diesem Beitrag beschriebene Fallstudie befasst sich mit dem Verhalten historischer Mauerwerkskonstruktionen beim Versagen infolge einer Erdbebenbelastung. Die Auswirkungen von Richtung und Frequenz eines Erdbebens sind die Hauptschwerpunkte der Studie. Ein kurz gefasster Hintergrund der gewählten Fallstudie und der Modellierungsprozess werden vorgestellt. Die Geometrie der gesamten Konstruktion wurde mittels Mikromodellierung erstellt. Die Versagensanalyse der Konstruktion ist mittels eines künstlich generierten Erdbebens durchgeführt worden. Das einachsige Erdbeben wurde mit variierenden Richtungswinkeln auf das Modell angesetzt, um die schwächste Achse zu ermitteln. Den Abschluss bildete die Erzeugung von verschiedenen Erdbebenverläufen in Abhängigkeit der Bodenprofile und Anwendung auf die Konstruktion, um wiederum den ungünstigsten Fall zu ermitteln.     

Neue Wege zur seismischen Ertüchtigung von Weltkulturerbe im Lehmbau: Das Beispiel der Zitadelle von Bam,Iran

Im Dezember 2003 zerstörte ein schweres Erdbeben die Stadt Bam in Südostiran. Opfer der verheerenden Zerstörung wurde nicht nur die bewohnte Neustadt, sondern auch die historische Zitadellenanlage aus Lehm. Sie ist eines der größten Komplexe, die komplett aus Lehmwerkstoffen errichtet worden sind. Die sofort im Anschluss ergriffenen Restaurierungs‐ und Rekonstruktionsbemühungen sind auf Grund des extremen Ausmaßes der Zerstörungen stark durch den Wunsch geprägt sowohl die geretteten Reste, als auch rekonstruierte Bauteile gegen seismische Einwirkungen zu ertüchtigen. In diesem Zusammenhang sind auch die Arbeiten des Lehrstuhls für Tragwerksplanung der TU Dresden (Inhaber Prof. W. Jäger) in Bam zu betrachten. Um dieser Aufgabenstellung in einer Weltkulturerbestätte gerecht zu werden, mussten neue Technologien entwickelt und in die Praxis umgesetzt werden. Diesen neuen Technologien widmet sich dieser Beitrag. New approaches for seismic retrofitting of world heritage: The Citadel of Bam, Iran. In December 2003 a heavy earthquake destroyed the city of Bam in southeast Iran. The destructions affected not only the new town of Bam but also the historical Citadel constructed entirely with earthen materials. The rehabilitation measures commenced immediately and are characterized by the desire of defining methods that strengthen the preserved rests against future seismic activity. The projects of the Dresden University of Technology, department of structural design (Head: Prof. Dr.‐Ing. W. Jaeger) presented here, are to be seen as a part of these efforts. In order to meet the demands of heritage conservation within a world heritage site (listed in 2004), new methods and technologies had to be developed and applied. The presented article intends to give a figure of these works.     

Open-loop output characteristics of a current feedback operational amplifier

The output characteristics of the basic current feedback operational amplifier (CFOA) in the linear region, on open-loop, would not appear to have been treated in the literature. This is possibly because it is not straightforward to determine, the problem being that the output saturates without the closed-loop connection. This paper considers a theoretical discussion that explains the results of simulation.