4,575 research outputs found

    A Note on Integer Factorization Using Lattices

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    We revisit Schnorr's lattice-based integer factorization algorithm, now with an effective point of view. We present effective versions of Theorem 2 of Schnorr's "Factoring integers and computing discrete logarithms via diophantine approximation" paper, as well as new elementary properties of the Prime Number Lattice bases of Schnorr and Adleman

    Repeatability and Two-Dimensionality of Model Scale Sloshing Impacts

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    Canonical test cases for sloshing wave impact problems are pre-sented and discussed. In these cases the experimental setup has been simpli?ed seeking the highest feasible repeatability; a rectangular tank subjected to harmonic roll motion has been the tested con?guration. Both lateral and roof impacts have been studied, since both cases are relevant in sloshing assessment and show speci?c dynamics. An analysis of the impact pressure of the ?rst four impact events is provided in all cases. It has been found that not in all cases a Gaussian ?tting of each individual peak is feasible. The tests have been conducted with both water and oil in order to obtain high and moderate Reynolds number data; the latter may be useful as simpler test cases to assess the capabilities of CFD codes in simulating sloshing impacts. The re-peatability of impact pressure values increases dramatically when using oil. In addition, a study of the two-dimensionality of the problem using a tank con?guration that can be adjusted to 4 di?erent thicknesses has been carried out. Though the kinemat-ics of the free surface does not change signi cantly in some of the cases, the impact pressure values of the ?rst impact events changes substantially from the small to the large aspect ratios thus meaning that attention has to be paid to this issue when reference data is used for validation of 2D and 3D CFD codes

    Geología de Andalucía

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    Montejo, Barnet, el cimarronaje y la escritura de la historia

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    Avoiding core's DUE & SDC via acoustic wave detectors and tailored error containment and recovery

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    The trend of downsizing transistors and operating voltage scaling has made the processor chip more sensitive against radiation phenomena making soft errors an important challenge. New reliability techniques for handling soft errors in the logic and memories that allow meeting the desired failures-in-time (FIT) target are key to keep harnessing the benefits of Moore's law. The failure to scale the soft error rate caused by particle strikes, may soon limit the total number of cores that one may have running at the same time. This paper proposes a light-weight and scalable architecture to eliminate silent data corruption errors (SDC) and detected unrecoverable errors (DUE) of a core. The architecture uses acoustic wave detectors for error detection. We propose to recover by confining the errors in the cache hierarchy, allowing us to deal with the relatively long detection latencies. Our results show that the proposed mechanism protects the whole core (logic, latches and memory arrays) incurring performance overhead as low as 0.60%. © 2014 IEEE.Peer ReviewedPostprint (author's final draft

    Absceso hepático que simula un tumor: reporte de un caso pediátrico

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    A case report of a 3-year-old boy with past medical history of intestinal partially treated amebiasis, is presented. The patient was admitted to Pediatric Unit, San Cristóbal Central Hospi- tal, Táchira, Venezuela, with abdominal pain and fever. An abdominal bloating and a 3 cm palpable hepatomegaly below the right costal margin were assessed. Abdominal ultrasound revealed a liver enlarged in the right antero-superior area. A rounded space-occupying lesion, predominantly solid, with mixed-echo patterns, was assessed using ultrasound. The preliminary diagnosis issued was of acute medical abdomen with hepatic space-occupying lesion considered amebic liver abscess or liver tumor, moderate hypochromic microcytic anemia, and malnutrition with short stature. During the case evolution, a frst computerized tomography exploration was necessary in order to exploit the capacity of this imaging tech- nique to scan an abscess as a peripheral pseudo-capsule showing rim enhancement. Nevertheless, this theoretical shape associated with abscesses on computerized tomog- raphy scans was unable to verify in this study. At this point, the mixed-echo patterns of the preliminary ultrasound study and the imprecision of the computerized tomography scan to categorize the lesion as an abscess or a tumor, do not allow establishing a defnitive diagnosis. A management based on antibiotic therapy is then proposed. The progression of the space-occupying lesion was performed using ultrasound and computerized tomography scans during the clinical evolution. The imaging controls probe a slight decrease of the liver le- sion, which is diagnosed as a liver abscess. Percutaneous transhepatic drainage was performed. An amoebic liver ab- scess in resolution was fnally diagnosed.Se presenta un case clínico de un niño de 3 años con antece- dentes médicos de amebiasis intestinal parcialmente tratada. El paciente ingresó en la Unidad de Pediatría del Hospital Central San Cristóbal, Táchira, Venezuela, con dolor abdomi- nal y febre. Se evaluó un abdomen plano y una hepatomega- lia palpable de 3 cm por debajo del reborde costal derecho. La ecografía abdominal reveló un hígado agrandado en el área anterosuperior derecha. Se evaluó una lesión ocupan- te de espacio redondeado, predominantemente sólida, con patrones de eco mixto, mediante ultrasonido. El diagnóstico preliminar emitido fue de abdomen médico agudo con lesión hepática ocupante de espacio considerada absceso hepático amebiano o tumor hepático, anemia microcítica hipocrómica moderada y desnutrición con talla baja. Durante la evolución del caso, fue necesaria una primera exploración de tomogra- fía computarizada para explotar la capacidad de esta técnica de imagen para escanear un absceso como una pseudocáp- sula periférica que muestra el borde realzado. Sin embar- go, esta forma teórica asociada con abscesos en tomografía computarizada no se pudo verifcar en este estudio. En este punto, los patrones de eco mixto del ultrasonido preliminar y la imprecisión de la tomografía computarizada para clasifcar la lesión como un absceso o un tumor, no permiten estable- cer un diagnóstico defnitivo. Se propone terapia con antibió- ticos. La progresión de la lesión ocupante de espacio se rea- lizó mediante ecografía y tomografía computarizada durante la evolución clínica. Los controles de imágenes refejan una ligera disminución de la lesión hepática, que se diagnostica como un absceso hepático. Se realizó drenaje transhepático percutáneo. Finalmente se diagnosticó un absceso hepático amebiano en resolución

    Comparative analysis of domestic water heating thermosiphon systems tested according to the Standard ISO 9459-2

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    Permiso concedido para subir el documentoThe Standard ISO 9459-2 is a standard for the characterization of thermal performance of domestic water heating systems without auxiliary heating. In this study, 18 domestic water heating thermosiphon systems have been tested according to this international standard. The objective of the paper is to carry out a comparative analysis of the results obtained in these systems as a function of their volume and type of heat exchanger (tubular and double jacket). A comparative analysis of systems performance will be carried out by calculating the performance without thermal loss (a1/A) and solar fraction fSOL in different reference locations for different volume/area ratios. Also, a comparative analysis of systems performance and solar fraction will be carried out at different locations between a tubular heat exchanger tank and a double jacket heat exchanger tank. The different values obtained will be compared for the storage tank’s heat loss coefficient (Us). It will determinate the useful energy (energy with temperature above 45ºC) for the degree of mixing in the storage tank during a draw-off test

    Penelope: The NBTI-aware processor

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    Transistors consist of lower number of atoms with every technology generation. Such atoms may be displaced due to the stress caused by high temperature, frequency and current, leading to failures. NBTI (negative bias temperature instability) is one of the most important sources of failure affecting transistors. NBTI degrades PMOS transistors whenever the voltage at the gate is negative (logic inputPeer ReviewedPostprint (published version
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