5,006 research outputs found

    New Constructions of Zero-Correlation Zone Sequences

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    In this paper, we propose three classes of systematic approaches for constructing zero correlation zone (ZCZ) sequence families. In most cases, these approaches are capable of generating sequence families that achieve the upper bounds on the family size (KK) and the ZCZ width (TT) for a given sequence period (NN). Our approaches can produce various binary and polyphase ZCZ families with desired parameters (N,K,T)(N,K,T) and alphabet size. They also provide additional tradeoffs amongst the above four system parameters and are less constrained by the alphabet size. Furthermore, the constructed families have nested-like property that can be either decomposed or combined to constitute smaller or larger ZCZ sequence sets. We make detailed comparisons with related works and present some extended properties. For each approach, we provide examples to numerically illustrate the proposed construction procedure.Comment: 37 pages, submitted to IEEE Transactions on Information Theor

    Rashba Spin Interferometer

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    A spin interferometer utilizing the Rashba effect is proposed. The novel design is composed of a one-dimensional (1D) straight wire and a 1D half-ring. By calculating the norm of the superposed wave function, we derive analytical expressions to describe the spin interference spectrum as a function of the Rashba coupling strength. Presented spin interference results are identified to include (i) the quantum-mechanical 4pi rotation effect, (ii) geometric effect, and (iii) Shubnikov-de Haas-like beating effect.Comment: 3 pages, 3 figures, appears in the proceedings of the 10th Joint MMM/Intermag Conferenc

    Quantum World-line Monte Carlo Method with Non-binary Loops and Its Application

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    A quantum world-line Monte Carlo method for high-symmetrical quantum models is proposed. Firstly, based on a representation of a partition function using the Matsubara formula, the principle of quantum world-line Monte Carlo methods is briefly outlined and a new algorithm using non-binary loops is given for quantum models with high symmetry as SU(N). The algorithm is called non-binary loop algorithm because of non-binary loop updatings. Secondary, one example of our numerical studies using the non-binary loop updating is shown. It is the problem of the ground state of two-dimensional SU(N) anti-ferromagnets. Our numerical study confirms that the ground state in the small N <= 4 case is a magnetic ordered Neel state, but the one in the large N >= 5 case has no magnetic order, and it becomes a dimer state.Comment: 14 pages, 5 figures, Invited talk at the 18th Annual Workshop on Recent Developments of Computer Simulation Studies in Condensed Matter Physics, Athens, 7-11 March, 200

    Realistic Type IIB Supersymmetric Minkowski Flux Vacua

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    We show that there exist supersymmetric Minkowski vacua on Type IIB toroidal orientifold with general flux compactifications where the RR tadpole cancellation conditions can be relaxed elegantly. Then we present a realistic Pati-Salam like model. At the string scale, the gauge symmetry can be broken down to the Standard Model (SM) gauge symmetry, the gauge coupling unification can be achieved naturally, and all the extra chiral exotic particles can be decoupled so that we have the supersymmetric SMs with/without SM singlet(s) below the string scale. The observed SM fermion masses and mixings can also be obtained. In addition, the unified gauge coupling, the dilaton, the complex structure moduli, the real parts of the K\"ahler moduli and the sum of the imaginary parts of the K\"ahler moduli can be determined as functions of the four-dimensional dilaton and fluxes, and can be estimated as well.Comment: RevTex4, 4 pages, 3 table

    Healthcare Information and the Utilization of Pap-smear Testing amongst Taiwanese Women

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    This study is to investigate the determinants of healthcare information amongst women in Taiwan aged between 25 and 69 years, and the association with cervical cancer screening.A two-stage estimation model was adopted for this investigation. In the first stage, the determinants of healthcare information were estimated by the OLS method, with the predicted values of the healthcare information then being linked to the decision to undergo Pap-smear testing. The nationwide survey dataset was obtained from the 2002‘Health Promotion of Knowledge, Attitudes and Practice' (HPKAP) in Taiwan, provided by the Bureau of Health Promotion. A total of 9,106 individuals were included in the analysis. The results reveal that the variations in the level of healthcare information are an important contributory factor to the utilization of cervical cancer screening in Taiwan. Therefore, in addition to providing free screening under the NHI, it is important for the healthcare authorities to place greater effort into strengthening the knowledge and information on cervical cancer screening and Pap-smear testing, for those who are currently less informed, so as to enhance the overall efficiency of the screening program.Health information; Pap-smear testing; Cervical cancer; National Health Insurance; Taiwan

    Broken spin-Hall accumulation symmetry by magnetic field and coexisted Rashba and Dresselhaus interactions

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    The spin-Hall effect in the two-dimensional electron gas (2DEG) generates symmetric out-of-plane spin Sz accumulation about the current axis in the absence of external magnetic field. Here we employ the real space Landauer-Keldysh formalism [B. K. Nikolic et al., Phys. Rev. Lett. 95, 046601 (2005); Phys. Rev. B 73, 075303 (2006)] by considering a four-terminal setup to investigate the circumstances in which this symmetry is broken. For the absence of Dresselhaus interaction, starting from the applied out-of-plane B corresponding to Zeeman splitting energy 0 - 0.5 times the Rashba hopping energy tR, the breaking process is clearly seen. The influence of the Rashba interaction on the magnetization of the 2DEG is studied herein. For coexisted Rashba tR and Dresselhaus tD spin-orbit couplings in the absence of B, interchanging tR and tD reverses the entire accumulation pattern.Comment: 3 pages, 2 figures, appears in the proceedings of 10th MMM/INTERMAG conferenc

    Motivation, Learning Strategies, and Language Competency in a Technology Facilitated Chinese as a Second Language Classroom

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    The present study examines the effectiveness of a game-based mobile technology application Kahoot on the motivation and language competency of high school student learning Chinese as a second language, and the relationship among student motivation, learning strategy use, and language competency in such a technology-facilitated classroom. Data was collected using pre and post surveys from a class of 18 students taught by a teacher candidate in a Chinese teaching licensure program at a state university. The results indicate significant student improvements in two areas of Chinese language learning: reading and speaking, though no significant difference was found in the areas of listening and vocabulary or in student motivation. Motivation and learning strategies were found to be positively related to Chinese proficiency, with the exception of cognitive and affective strategies which mainly correlate with Chinese speaking competency. Findings and limitations of the study were discussed and implications for future research were suggested
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