10,687 research outputs found

    Implementation of Fast, Low Power and Area Efficient Carry Select Adder

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    One of the fastest adders is Carry Select Adder (CSLA) and it perform fast arithmetic functions in many data processing processors. A conventional CSLA has less carry propagation delay (CPD) than ripple carry adder (RCA). A compromise between RCA and carry look ahead adder is provided by Carry select adder. For the CSLA new logic is proposed by reducing redundant logic operations present in conventional CSLA. In the proposed scheme, schedule the carry select (CS) operation before final sum calculation. which is different approach from the conventional. Two carry words ( cin = 0 and 1) bit patterns and fixed cin bits use for generation units and CS logic optimization. Optimized logic units is used to obtain an efficient CSLA design. The proposed work is carried out using Modelsim SE 6.3f and Quatus2 software. DOI: 10.17762/ijritcc2321-8169.16046

    Purification of Mixed State with Closed Timelike Curve is not Possible

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    In ordinary quantum theory any mixed state can be purified in an enlarged Hilbert space by bringing an ancillary system. The purified state does not depend on the state of any extraneous system with which the mixed state is going to interact and on the physical interaction. Here, we prove that it is not possible to purify a mixed state that traverses a closed time like curve (CTC) and allowed to interact in a consistent way with a causality-respecting (CR) quantum system in the same manner. Thus, in general for arbitrary interactions between CR and CTC systems there is no universal 'Church of the larger Hilbert space' for mixed states with CTC. This shows that in quantum theory with CTCs there can exist 'proper' and 'improper' mixtures.Comment: Latex2e, No Figs, 4 + pages, An error corrected, Results unchange

    Quantum Frequency Translation of Single-Photon States in Photonic Crystal Fiber

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    We experimentally demonstrate frequency translation of a nonclassical optical field via the Bragg scattering four-wave mixing process in a photonic crystal fiber (PCF). The high nonlinearity and the ability to control dispersion in PCF enable efficient translation between photon channels within the visible to-near-infrared spectral range, useful in quantum networks. Heralded single photons at 683 nm were translated to 659 nm with an efficiency of 28.6±2.228.6 \pm 2.2 percent. Second-order correlation measurements on the 683-nm and 659-nm fields yielded g683(2)(0)=0.21±0.02g^{(2)}_{683}(0) = 0.21 \pm 0.02 and g659(2)(0)=0.19±0.05g^{(2)}_{659}(0) = 0.19 \pm 0.05 respectively, showing the nonclassical nature of both fields.Comment: 5 pages, 3 figure

    Using patterns position distribution for software failure detection

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    Pattern-based software failure detection is an important topic of research in recent years. In this method, a set of patterns from program execution traces are extracted, and represented as features, while their occurrence frequencies are treated as the corresponding feature values. But this conventional method has its limitation due to ignore the pattern’s position information, which is important for the classification of program traces. Patterns occurs in the different positions of the trace are likely to represent different meanings. In this paper, we present a novel approach for using pattern’s position distribution as features to detect software failure. The comparative experiments in both artificial and real datasets show the effectiveness of this method

    An Examination of Emotions in the Boston Bombing Twitterverse

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    Social Network Services (SNS) such as Twitter play an important role in the way people share their emotions or cognitions regarding specific events. Emotions can be spread via SNS and can spur user’s actions. Therefore, managing emotion in SNS is important. In this Research In Progress, we investigate Twitterverse that is associated with event related hazard describing keywords (Explosion, Bomb) and their related emotions in the Boston Bombing context. We compare the results with an exploration of Twitterverse that is not associated with the above hazard describing keywords. A sentiment analysis shows Positive emotion, Discrepancy, Tentativeness, and Certainty had consistent patterns over five days of the Boston Bombing incident. When keywords were excluded, the expressed emotions or cognition were higher than when were keywords included. This paper contributes by examining how emotion and cognition differed across keywords relating to the extreme event

    Emergence of geometrical optical nonlinearities in photonic crystal fiber nanowires

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    We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of which is strongly dependent on the waveguide parameters) which acts on solitons so as to considerably reduce their Raman self-frequency shift. An explanation of the phenomenon in terms of indirect pulse negative chirping and broadening is given by using the moment method. Our conclusions are supported by detailed numerical simulations.Comment: 5 pages, 3 figure

    Multidimensional Tests of Thermal Protection Materials in the Arcjet Test Facility

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    Many thermal protection system materials used for spacecraft heatshields have anisotropic thermal properties, causing them to display significantly different thermal characteristics in different directions, when subjected to a heating environment during flight or arcjet tests. This paper investigates the effects of sidewall heating coupled with anisotropic thermal properties of thermal protection materials in the arcjet environment. Phenolic Impregnated Carbon Ablator (PICA) and LI-2200 materials (the insulation material of Shuttle tiles) were used for this study. First, conduction-based thermal response simulations were carried out, using the Marc.Mentat finite element solver, to study the effects of sidewall heating on PICA arcjet coupons. The simulation showed that sidewall heating plays a significant role in thermal response of these models. Arcjet tests at the Aerodynamic Heating Facility (AHF) at NASA Ames Research Center were performed later on instrumented coupons to obtain temperature history at sidewall and various radial locations. The details of instrumentation and experimental technique are the prime focus of this paper. The results obtained from testing confirmed that sidewall heating plays a significant role in thermal response of these models. The test results were later used to verify the two-dimensional ablation, thermal response, and sizing program, TITAN. The test data and model predictions were found to be in excellent agreemen
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