7,015 research outputs found

    Structure of semisimple Hopf algebras of dimension p2q2p^2q^2

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    Let p,qp,q be prime numbers with p4<qp^4<q, and kk an algebraically closed field of characteristic 0. We show that semisimple Hopf algebras of dimension p2q2p^2q^2 can be constructed either from group algebras and their duals by means of extensions, or from Radford biproduct R#kG, where kGkG is the group algebra of group GG of order p2p^2, RR is a semisimple Yetter-Drinfeld Hopf algebra in kGkGYD{}^{kG}_{kG}\mathcal{YD} of dimension q2q^2. As an application, the special case that the structure of semisimple Hopf algebras of dimension 4q24q^2 is given.Comment: 11pages, to appear in Communications in Algebr

    Computational Soundness for Dalvik Bytecode

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    Automatically analyzing information flow within Android applications that rely on cryptographic operations with their computational security guarantees imposes formidable challenges that existing approaches for understanding an app's behavior struggle to meet. These approaches do not distinguish cryptographic and non-cryptographic operations, and hence do not account for cryptographic protections: f(m) is considered sensitive for a sensitive message m irrespective of potential secrecy properties offered by a cryptographic operation f. These approaches consequently provide a safe approximation of the app's behavior, but they mistakenly classify a large fraction of apps as potentially insecure and consequently yield overly pessimistic results. In this paper, we show how cryptographic operations can be faithfully included into existing approaches for automated app analysis. To this end, we first show how cryptographic operations can be expressed as symbolic abstractions within the comprehensive Dalvik bytecode language. These abstractions are accessible to automated analysis, and they can be conveniently added to existing app analysis tools using minor changes in their semantics. Second, we show that our abstractions are faithful by providing the first computational soundness result for Dalvik bytecode, i.e., the absence of attacks against our symbolically abstracted program entails the absence of any attacks against a suitable cryptographic program realization. We cast our computational soundness result in the CoSP framework, which makes the result modular and composable.Comment: Technical report for the ACM CCS 2016 conference pape

    Entropy, fidelity, and double orthogonality for resonance states in two-electron quantum dots

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    Resonance states of a two-electron quantum dot are studied using a variational expansion with both real basis-set functions and complex scaling methods. The two-electron entanglement (linear entropy) is calculated as a function of the electron repulsion at both sides of the critical value, where the ground (bound) state becomes a resonance (unbound) state. The linear entropy and fidelity and double orthogonality functions are compared as methods for the determination of the real part of the energy of a resonance. The complex linear entropy of a resonance state is introduced using complex scaling formalism

    Teaching C/C ++ programming using a multimedia system with videos

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    The C programming language is widely used in computer and industrial engineering. Because of that, such programming language is also widely used as a language to teach programming to industrial engineering students. In Spain, many universities use this language compulsory in the first year, or even in higher courses. Our experience shows that learning computer programming in four months is an arduous task, but curricula require it. Such learning process is also tough by the fact that many students cannot attend classes regularly and, even if they attend, sometimes the class is no longer at the level they require. In this work we develop a series of files in "presentation" format (.ppsx) and videos that allow students to see several explanations about the most complicated programming C topics: functions, arrays, structures, strings, arrays with structures, etc. This multimedia material includes explanations (voice-over), and animations with examples. Students can watch and listen to the explanations whenever and wherever they want (tablet, PC, phone…). Surveys made to students reveal that it is also interesting for students who regularly attend classes, and they prefer to use this course material only at home, outside of regular classes.El lenguaje de programación C se utiliza mucho en informática e ingeniería industrial. Por tanto, dicho lenguaje de programación también se utiliza mucho como lenguaje para enseñar programación a estudiantes de ingeniería industrial. En España, muchas universidades usan este lenguaje de forma obligatoria durante el primer año, o incluso en cursos superiores. Nuestra experiencia indica que aprender programación de computadoras en cuatro meses es una tarea ardua, pero los currículos lo requieren. Tal proceso de aprendizaje también es difícil por el hecho de que muchos estudiantes no pueden asistir a clases regularmente e, incluso si asisten, a veces la clase ya no está en el nivel que requieren. En este trabajo desarrollamos una serie de archivos en formato de "presentación" (.ppsx) y videos que permiten a los estudiantes ver varias explicaciones sobre los temas de programación C más complicados: funciones, matrices, estructuras, cadenas, matrices con estructuras, etc. El material multimedia incluye explicaciones (voz en off) y animaciones con ejemplos. Los estudiantes pueden ver y escuchar las explicaciones cuando y donde quieran (tableta, PC, teléfono, etc.). Las encuestas realizadas revelan que también es interesante para los estudiantes que asisten regularmente a clases, y que prefieren usar este material del curso solo en casa, fuera de las clases regulares

    Effects of bilingual intervention on alphabet knowledge and emergent literacy skills

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    This research study explored the effects of bilingual intervention on the development of alphabet knowledge and emergent literacy skills in bilingual kindergarten students. The study consisted of 15 African- American or Hispanic participants’ ages five and six, 7 of which were part of the intervention group. The intervention group received explicit bilingual literacy instruction for six weeks. Three major findings were 1) student participants experienced increased alphabet knowledge in their first and second language 2) students demonstrated growth in emergent literacy skills in their first language and 3), the students’ first language development was not negatively affected by the bilingual intervention in the second language. The results indicate that explicit bilingual intervention is beneficial for the development of alphabet knowledge and emergent literacy skills
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