723 research outputs found

    A bistatic linear frequency modulated radar for on-the-ground object detection

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    The use of radar systems for detecting on-the-ground objects is a subject of interest for some applications. Among them, foreign object detection systems are important issues in airport aviation safety. Due to the characteristics of the object, a ground-based bistatic radar configuration is introduced in this article. The transmitter sends broadband linear frequency modulated chirp pulses. The reflected pulses are collected simultaneously by at least two ground-based receivers installed in different positions. Accurate range processing is conducted to detect small objects, such as N-type connectors in distances of several meters. A prototype system consisting of one transmitter and two receivers is developed. The system is then launched over land similar in appearance to a runway, and its ability to make an accurate image of the area where the object is placed in different positions is confirmed. Modifications that need to cover a bigger area are also discussed. The system resolution is analyzed and shows that in the case of several existing transmitter-receiver pairs, the best resolution can be achieved by the closer pairs

    Experimental investigation on target detection and tracking in passive radar using long-term evolution signal

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    This study examines the feasibility of the recently deployed wireless communication system, namely, long-term evolution (LTE), for passive radar applications. Specifically, the capability of the system to detect and track a ground moving target is analysed. A theoretical analysis is conducted on the actual LTE signal transmitted in the atmosphere, followed by field experimentation using a moving vehicle with different bistatic geometries. The experiment examines the capability of an LTE-based passive radar to detect a moving vehicle and then track it using a standard Kalman filter. Results show that the LTE-based passive radar can detect and track the ground vehicle at different locations, speeds and trajectories, and localise it in the XY-axis coordinate

    Mixing Biometric Data For Generating Joint Identities and Preserving Privacy

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    Biometrics is the science of automatically recognizing individuals by utilizing biological traits such as fingerprints, face, iris and voice. A classical biometric system digitizes the human body and uses this digitized identity for human recognition. In this work, we introduce the concept of mixing biometrics. Mixing biometrics refers to the process of generating a new biometric image by fusing images of different fingers, different faces, or different irises. The resultant mixed image can be used directly in the feature extraction and matching stages of an existing biometric system. In this regard, we design and systematically evaluate novel methods for generating mixed images for the fingerprint, iris and face modalities. Further, we extend the concept of mixing to accommodate two distinct modalities of an individual, viz., fingerprint and iris. The utility of mixing biometrics is demonstrated in two different applications. The first application deals with the issue of generating a joint digital identity. A joint identity inherits its uniqueness from two or more individuals and can be used in scenarios such as joint bank accounts or two-man rule systems. The second application deals with the issue of biometric privacy, where the concept of mixing is used for de-identifying or obscuring biometric images and for generating cancelable biometrics. Extensive experimental analysis suggests that the concept of biometric mixing has several benefits and can be easily incorporated into existing biometric systems

    The issue of the development of material package for protective cloth designing

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    Introduction: The article presents the characteristics of existing materials of top, heat-insulating and lining materials which are used for the design of protective clothing. A number of comparative analyses of the studied materials for further use them as a package in overalls was carried out. Materials and Methods: When writing, various methods were used, such as the comparison method, the historical method, the market analysis method, and others. Results and Discussion: We have researched the various fabrics and non-fabrics produced and used in industry that fall under the category of protective fabrics. Conclusions: As a result of a comparative, bibliometric analysis, it was revealed that a wide variety of different special-purpose materials is currently on the market

    Fresh leafy green vegetables associated with multidrug resistant E.coli

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    Background: Recent outbreaks of  E. coli diarrheal diseases linked to the consumption of  fresh green produce, has raised a global concern about bacterial pathogens that cause food borne diseases. While little attention have been devoted to contamination of fresh green food with drug resistance bacteria species. Objective: To detect the occurrence of contamination and antibiotic resistance in E. coli isolates from fresh leafy vegetables presented in Jordanian retail markets. Study design: A total 150 fresh leafy green vegetable samples were collected from different markets in Amman and Al-Zarqa in Jordan over the five months; June through October, 2010  . Results: A total of 61 (40.6%) E. coli isolates were found as contaminates of 150 fresh leafy green vegetable samples. The highest contamination with E. coli occurred in parsley and lowest in Lettuce.  A range of  3-41% of E. coli isolates were resistant to 7 common antibiotics used often in the treatment of urinary tract infection in Jordan. A total of 17 (27.8%) E. coli isolates were resistant to three or more antimicrobial agents and considered to be multidrug resistant. Of these, 14(82%) isolates were positive for class 1 integron, 17(100%) carry at least one plasmid with a common sizes (7.3 and 54.3 Kb), 12(70.6%),  and  2(11.8%) isolates were positive for Tet A and Tet B genes, respectively. A total of 15 (88.2%) isolates were positive for sul2 and 4 (23.5%) isolates for sul1 gene. Conclusion: This study demonstrates the widespread of antimicrobial resistance in E. coli contaminating fresh green produce and which may increase the reservoir of antimicrobial resistance in the intestinal tract of Jordanian population

    On OSTBC Codes for LTE-A Systems-Design and Performance Evaluation

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    Long Term Evolution-Advanced (LTE-A) is a Fourth Generation (4G) standard of wireless communications that introduces high data rate, high performance, and low delay. These features of LTE-A resulted from the new techniques developed for wireless communications such as Multiple-Input Multiple-Output (MIMO) technique. At the heart of this technique is the Space Time Codes, which were developed by the researchers in recent decades to achieve the mentioned features. The designs of OSTBC codes for MIMO systems having any number of transmit antennas and any number of receive antennas have attracted the attention of many researchers. Based on the theory of real and complex orthogonal designs, this paper deals with the design of real and complex OSTBC codes to be used with real signal set constellation such PAM and complex signal constellation such as PSK and QAM. Real and complex OSTBC codes for MIMO systems with two, three, four, five, six, seven and eight transmit antennas and any number of receive antennas, are presented. Simple linear processing ML decoders are derived and presented. The used channel is Rayleigh fading channel MIMO and assumed to behave in a “quasi-static” fashion. Finally, the performances of OSTBC schemes were evaluated and compared in terms of the Bit Error Rate (BER) and Signal to Noise Ratio (SNR). The environment of simulation is MATLAB which is a powerful tool for mathematical calculation and system simulation. The methods of modulations chosen are QPSK, 16QAM, 64QAM, and 128QAM with gray scale mapping

    Molecular characterization of Pseudomonas aeruginosa isolates from various clinical specimens in Khartoum/Sudan: Antimicrobial resistance and virulence genes

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    Background: Pseudomonas aeruginosa is a pathogenic organism responsible for frequent wound and nosocomial infections worldwide. Its infections are difficult to control since the organism is known to rapidly develop antibiotic resistance and becomes multidrug-resistant (MDR) during treatment of patients. Aim of the study: This study was intended to investigate the occurrence of certain important types of (ESBL) and (MBL) enzymes in association with important specific virulence factors  associated with P. aeruginosa clinical isolates from Khartoum, Sudan. Methods: This study investigated 70 P. aeruginosa isolates which were collected from patients admitted to four major hospitals in Khartoum  (Fedail, Ribat, Ibn Sina and Soba hospitals). These isolates were recovered from 40 wound swabs (57.1%), 27 urine samples (38.6%), and 3 pleural fluid samples (4.3%) of patients. Higher numbers of isolates were recovered from males 42 (60%) than in females 28 (40%). All P. aeruginosa isolates were first confirmed by conventional biochemical and second using molecular PCR tests.   PCR methods were also used for detecting the presence of the virulence genes ToxA, AlgD, LasB, exoS, exoU, CTX, GES-1, and genes of VIM, IMP, KPC, CTX, VEB-1 and SHV-1. Results:   Antimicrobial susceptibility testing of P. aeruginosa isolates showed a high resistance to azetronam 49 (70%), followed by ceftazidime 32 (45.7%), 16 ciprofloxacin (22.9%), gentamicin 13 (18.6 %), piperacillin-tazobactam 11 (15.7%), amikacin 9 (12.9 %), and imipenem 6 (8.6%) showed the least resistance. All isolates were positive for algD and lasB (100%), followed by toxA (90%), exoS (34.3), exoU (24.3%), respectively. The rates of detected ESBL genes blaTEM, blaCTX-m, blaSHV-1,GES-1, were 3.3%, 6.6%, 10%, 3.3%,10%, respectively, but all isolates were negative for bla-KPC and bla- VIM and IMP . The percentages of pigment production were 61.4% for pyocyanin, 37.1% for pyoverdin and 1.4% for pyorubin. Conclusion: The study demonstrated high rates of antimicrobial resistance markers to most commonly used antibiotics in treatment of P. aeruginosa infections. The majority of the isolates from urine and wound samples carried at least three potential virulence factor genes of algD, lasB and toxA and without any significant relation to their antimicrobial resistance markers. &nbsp

    Microbiology, diseases, and epidemiology of Kingella kingae in young children: A short review

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    Kingella kingae is a Gram-negative coccobacilli and it is a member of the HACEK (Haemophilus species, Aggregatibacte actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and  K. kingae). HACEK organisms are typically oropharyngeal commensals and have long been recognized as a cause of infective endocarditis in children and adults. K. kingae in difficult to be recovered from cultured pharyngeal samples due to its slow growth and the high presence of resident bacterial flora, however, the organism can be better detected using PCR tests. Based on our search in PubMed and other sources, we couldn't discover any study about K. kingae originated from any Arab country. Therefore, we wrote this review to draw the attention of our physicians and clinical microbiologists on the importance of this neglected group of organisms in clinical medicine.   However, this review article aims to cover the most important diseases of K. kingae in the pediatric population
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