4,109 research outputs found

    Analysis of the Security of BB84 by Model Checking

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    Quantum Cryptography or Quantum key distribution (QKD) is a technique that allows the secure distribution of a bit string, used as key in cryptographic protocols. When it was noted that quantum computers could break public key cryptosystems based on number theory extensive studies have been undertaken on QKD. Based on quantum mechanics, QKD offers unconditionally secure communication. Now, the progress of research in this field allows the anticipation of QKD to be available outside of laboratories within the next few years. Efforts are made to improve the performance and reliability of the implemented technologies. But several challenges remain despite this big progress. The task of how to test the apparatuses of QKD For example did not yet receive enough attention. These devises become complex and demand a big verification effort. In this paper we are interested in an approach based on the technique of probabilistic model checking for studying quantum information. Precisely, we use the PRISM tool to analyze the security of BB84 protocol and we are focused on the specific security property of eavesdropping detection. We show that this property is affected by the parameters of quantum channel and the power of eavesdropper.Comment: 12 Pages, IJNS

    The Cognitive Economy: An approach to Developing the Faculties of Education Competitive Abilities

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    The current study aimes at recognizing the cognitive economy reality at the faculties of education and the effect of its dimensions on developing the competitive abilities of the faculties of education. The two researchers used the perspective method . Two questionnaires were prepared. The first one was applied on a sample of staff members at the faculties of education, which it concluded (117) person in order to; recognize the reality of the cognitive economy at the faculties of education and the effect of its dimensions on developing their competitive abilities. The second questionnaire was applied on the same previous sample in order to; recognize the requirements of the cognitive economy at the faculties of education to increase its competitive abilities. The study came down to several results, most important of which were the agreement of the sample individuals, as whole, that ,the requirements of the cognitive economy at the faculties of education that increase its competitive abilities, were represented in evolving information technology and telecoms, the curriculum, the service and research programs, enabling staff members to participate in the activities of information mobility of human principals among universities, giving students the technological skills concerning the international markets and sharing at the unions of the pioneering international universities in the field of information technology and telecoms. The researcher concluded with setting a suggested proposal that included aims, fundamentals, mechanisms and guarantees to achieve the cognitive economy as an Approach to developing the competitive abilities of the faculties of education

    Radiochemical Studies Relevant to Cyclotron Production of the Radionuclides 71,72As, 68Ge/68Ga and 76,77,80mBr

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    Die Radionuklide 71,72,73,74As, 68Ge/68Ga und 76,77,80mBr gewinnen großes Interesse in der Nuklearmedizin. Ein Verfahren zur Abtrennung von nicht-geträgerten Arsen-Radionukliden aus den großen Mengen des mit Protonenbestrahlte GeO2-Targets sowie aus koproduzierten Radiogalliumisotopen wurde entwickelt. Die Gewinnung von Radioarsen mittels verschiedener organischer Lösungsmitteln aus sauren Lösungen unter Zusatz von Alkalijodid wurde untersucht und optimiert. Der Einfluss der Konzentration verschiedener Säuren (HCl, HClO4, HNO3, HBr, H2SO4) sowie des KI wurde auf die Extraktion mit Cyclohexan untersucht. Die praktische Anwendung des optimierten Verfahrens bei der Produktion von 71As und 72As wurde demonstriert. Die Gesamtausbeuten lagen im Bereich von 75-84% der theoretischen Werte. Die radiochemische Trennung von Radiogallium aus Radiogermanium wurde mittels Ionenaustausch-Chromatographie (Amberlite IR-120) und Solventextraktion mit Aliquat 336 in o-Xylol untersucht. Dazu wurden zunächst der Radiotracer 69Ge aus einem bestrahlten Ga2O3-Target und des 67Ga aus einem Zn-Target abgetrennt. Sie wurden durch die Kernreaktion natGa (p,xn)69 Ge bzw natZn (p,xn)67Ga. hergestellt. Mehrere Faktoren, die die Trennung von Radiogallium aus Radiogermanium beeinflussen wurden untersucht und für jedes Verfahren werden die optimalen Bedingungen ermittelt. Die Lösungsmittelextraktion mit Aliquat 336 erwies sich als besser geeignet und wurde deshalb zur Trennung von 68Ga aus dem Mutternuklid 68Ge herangezogen. Die Qualität des so erhaltenen Produkts wird diskutiert. Die Trennung von nicht-geträgertem Radiobrom und Radiogallium aus dem bestrahlten ZnSe-Target wurde entwickelt. Dazu wurde das Adsorptionsverhalten von Radiobrom, Radiogallium, Zink und von Selen auf dem Kationenaustauscher Amberlyst 15, in H+ Form sowie dem Anionenaustauscher Dowex 1x10 in Cl- und OH- Formen, untersucht. Die Elution des Radiobroms und des Radiogalliums wurde mit Hilfe verschiedener Lösungsmittel verfolgt. Zusätzlich wurde die Trennung von Radiobrom über die Lösungsmittelextraktion mit TOA in o-Xylol durchgeführt. Schließlich wurde ein optimiertes Verfahren zur Herstellung von 77Br und 67Ga entwickelt, und die Qualitätskontrolle der Produkte wurde durchgeführt. Die Kernreaktionsdaten zur Produktion des Auger-Elektronen-emittierenden Radionuklides 80mBr (T1/2 = 4,4 h) wurden unter Anwendung des angereicherten 80Se als Targetmaterial bestimmt. Dünne 80Se- Proben wurden mit einfallenden Protonen mit Energien bis zu 18 MeV bestrahlt und die induzierte Radioaktivität wurde durch zerstörungsfreie γ-Spektroskopie gemessen, so dass die Bestimmung und Erweiterung der Anregungsfunktion der Kernreaktion 80Se(p,n)80mBr erfolgen konnte. Die integrale Ausbeute wurde berechnet und die geeigneten Energiebereiche für die Produktion wurden ermittelt, insbesondere im Hinblick auf die Ausbeute und die radionuklidische Reinheit des produzierten Radionuklids

    A study of iron based alloys by positron annihilation spectroscopy

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    Long-term outcomes of transobturator tension-free vaginal tapes as secondary continence procedures

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    Acknowledgements We thank Dr. Karmakar (Research Fellow— University of Aberdeen) for sending out the questionnaires and collating the responses. We thank Lindsey Grant for performing the independent data entry cross-check. A special gratitude goes to all the participants whose excellent cooperation over the years made this study successful. Funding The initial phase of this study (up to 3-year follow-up) was funded by the Henry Smith Charity. Dr. Karmakar was funded by IUGA Clinical Fellowship Grant 2014.Peer reviewedPostprin

    Theoretical and Analytical Investigation of Electromagnetic Problems Using Dispersive Material and the Kramers-Kronig Transformations

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    In reality, there is no material with constant permittivity, permeability, and conductivity values over the entire frequency spectrum. The variation in these parameters is well-known as the dispersion phenomenon, which can be analytically interpreted using the Kramers-Kronig relations. Through this thesis, we extensively explain how to take advantage of the dispersion in these parameters to numerically investigate some electromagnetic problems. Among these is a practical problem of separating the electric conductive losses from the dielectric losses of any dispersive lossy material. On the other hand, the performance of particular electrically small antennas is improved by exploiting the frequency dispersion in the dielectric and magnetic material. Electrically small antennas have great attention in many applications due to their drastically reduced size. However, the size reduction comes at the expense of performance degradation, such as increasing the internally stored electromagnetic energy, narrowing the operating bandwidth, decreasing radiation efficiency, and poor matching to surrounding media, particularly when the antenna element has direct contact with a lossy medium like biomedical tissues. Therefore, we try to numerically investigate the performance of these antennas by coating them with dispersive dielectric or magnetic material. In this thesis, some artificially synthesized material with frequency-dependent permittivity, permeability, and electric conductivity values over a wide range of frequencies are suggested to represent the dispersive lossy material. The Kramers-Kronig (KK) relations are employed as a mathematical solution to interrelate the real and imaginary parts of the suggested frequency-dependent relative permittivity and permeability values of the artificial material. Finally, the solution methods are verified by applying them to real-world material found in the literature

    Constructing and Norming Arabic Screening Tool of Auditory Processing Disorders: Evaluation in a Group of Children at Risk for Learning Disability

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    The purposes of this study were to develop and provide the normative data of Arabic screening tool for screening the children with auditory processing disorders: an Arabic version of Adaptive Auditory Speech Test (AAST) in quiet for screening the peripheral hearing in dB SPL units; an Arabic AAST in binaural noise for screening the temporal interaction deficit: listening speech in binaural noise in dB SNR units, then teetaatoo test with a five subtests for screening the Modern Standard Arabic language phonemes identification ability. Participants included 338 children aged from 5 to 7 years old (138 males, 200 females; mean age = 6.08 years with standard deviation = 0.8) from a regular nursery school which called Baroot Summer Club in Beni-Suef in Egypt were recruited to participate in the study. According to the calculated Norms of AAST in quiet and through a meeting with the teachers of children in the nursery school, 129 children were sift out with no hearing loss, negative histories of neurological disorders, head trauma or surgery, dizziness, and attention deficit disorder/attention deficit hyperactivity disorder. 129 children were screened for listening in binaural noise using the Arabic AAST in binaural noise, then the left 94 children, because 35 children couldn`t complete the testing, was screened for phonemes identification ability using teetaatoo test(the five sub tests). For the AAST in quiet, 21 to 33 dB SPL is the normal range of the hearing peripheral loss, especially, for the AAST in binaural noise, there are three different norms; -9 to -13 dB SNR is the normal range of children aged 5 years old, -10 to -13 dB SNR is the normal range of children aged 6 years old, and -10 to -14 dB SNR is the normal range of children aged 7 years old. Finally, for the five subtests (teetaatoo): > 85% (correct answers) is the normal percentage of the Cons-A, >62& (correct answers) is the normal percentage of the Cons-B1, >76% is the normal percentage of the Cons-B2, >63% (correct answers) is the normal percentage of the Cons-B3, and 84% (correct answers) is the normal percentage of the Vow-A. Further, according to the previous norms, 23 children represent 17,8% from the whole sample (N=129) with a normal speech recognition threshold have scored abnormally on the speech listening in bin-noise (AAST in bin-noise) or on at least one subtest from teetaatoo subtests and were considered at risk for learning disability because of their scores on a SIFTER
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