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.     

Determination of a model partial safety factor for unreinforced masonry walls under buckling

The design/verification method in the Eurocodes is based on the partial safety concept. Eurocode 6 suggests a constant partial safety factor for the material γ_M for all design/verification problems, without consideration of model uncertainty in the design/verification formula. In the following, a model partial safety factor is determined for the problem of unreinforced masonry walls mainly subjected to vertical loading. For that purpose, the newly proposed formula for EC 6, annex G will be considered [1–3]. In order to cover all aspects in tests and to use the results for design purposes, several methods have been included in EN 1990 Annex D for design based on test data. In this study, the recommended methods in Annex D of EN 1990 for resistance of the material are used to extract the partial safety factors. A database including more than 119 experimental tests on unreinforced masonry shear walls is used to compare the model prediction and the test results and to determine the model partial safety factor.     

Novel input stages for current feedback operational amplifiers

This paper considers the trade-offs involved in the design of six new input stages intended to improve the performance of a current feedback operational amplifier (CFOA), over that possible using an established input circuit configuration, with respect to three major characteristics, viz, common mode rejection ratio (CMRR), offset voltage and slew-rate.     

Wegener''s granulomatosis. First case report in Bahrain

PURPOSE: To consider and differentiate oedema fluid from other fluids in the performance of epidural block. CLINICAL FEATURES: A patient underwent placement of an epidural catheter for vaginal delivery of twins. Following a loss of resistance technique using air a small amount of fluid was aspirated through the needle and subsequently through the epidural catheter. The epidural block and delivery followed uneventfully. After delivery oedema fluid oozed from the puncture site for a number of days. Laboratory investigation revealed that this fluid was of oedematous origin. Bedside determination of alkaline pH by Combur 10 Test M urine stick appeared to be a simple and useful test for distinguishing the oedema fluid from fluids of other possible sources. CONCLUSION: When performing an epidural blockade the return of fluid may be due to oedematous fluid. Differentiation of the pH by a simple bedside test can aid in the differential diagnosis and prevent unnecessary additional attempts at needle repositioning.