666 research outputs found

    A cognitive control approach to interference mitigation in communications-based train control (CBTC) co-existing with passenger information systems (PISs)

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    As a key component of urban rail transit systems, communications-based train control (CBTC) is an automated train control system using train-ground communications to ensure efficient operation of rail vehicles. In addition to CBTC systems, passenger information systems (PISs) are adopted in urban rail transit systems to improve quality of service (QoS) offered to customers. The interference between CBTC systems and PISs is an important factor impacting QoS of both CBTC systems and PISs. With recent advances in cognitive dynamic systems, in this paper, we take a cognitive control approach to interference mitigation considering the co-existence of CBTC systems and PISs. In our cognitive control approach, the notion of information gap is adopted to quantitatively describe effects of interference on CBTC. The wireless channel is modeled as a finite-state Markov chain with multiple state transition probability matrices, which are derived from real field measurements. Simulation results show that the proposed cognitive control approach can significantly improve performance of CBTC train-ground communications under interference from

    The magnetic dipole transitions in the (cbˉ)(c\bar{b}) binding system

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    The magnetic dipole transitions between the vector mesons Bc∗B_c^* and their relevant pseudoscalar mesons BcB_c (BcB_c, Bc∗B_c^*, Bc(2S)B_c(2S), Bc∗(2S)B_c^*(2S), Bc(3S)B_c(3S) and Bc∗(3S)B_c^*(3S) etc, the binding states of (cbˉ)(c\bar{b}) system) of the BcB_c family are interesting. To see the `hyperfine' splitting due to spin-spin interaction is an important topic for understanding the spin-spin interaction and the spectrum of the the (cbˉ)(c\bar{b}) binding system. The knowledge about the magnetic dipole transitions is also very useful for identifying the vector boson Bc∗B_c^* mesons experimentally, whose masses are just slightly above the masses of their relevant pseudoscalar mesons BcB_c accordingly. Considering the possibility to observe the vector mesons via the transitions at Z0Z^0 factory and the potentially usages of the theoretical estimate on the transitions, we fucus our efforts on calculating the magnetic dipole transitions, i.e. precisely to calculate the rates for the transitions such as decays Bc∗→BcγB_c^*\to B_c\gamma and Bc∗→Bce+e−B_c^*\to B_c e^+e^-, and particularly work in the Behte-Salpeter framework. In the estimate, as a typical example, we carefully investigate the dependance of the rate Γ(Bc∗→Bcγ)\Gamma(B_c^*\to B_c\gamma) on the mass difference ΔM=MBc∗−MBc\Delta M=M_{B_c^*}-M_{B_c} as well.Comment: 10 pages, 2 figures, 1 tabl

    Reconstructing the properties of dark energy from recent observations

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    We explore the properties of dark energy from recent observational data, including the Gold Sne Ia, the baryonic acoustic oscillation peak from SDSS, the CMB shift parameter from WMAP3, the X-ray gas mass fraction in cluster and the Hubble parameter versus redshift. The ΛCDM\Lambda CDM model with curvature and two parameterized dark energy models are studied. For the ΛCDM\Lambda CDM model, we find that the flat universe is consistent with observations at the 1σ1\sigma confidence level and a closed universe is slightly favored by these data. For two parameterized dark energy models, with the prior given on the present matter density, Ωm0\Omega_{m0}, with Ωm0=0.24\Omega_{m0}=0.24, Ωm0=0.28\Omega_{m0}=0.28 and Ωm0=0.32\Omega_{m0}=0.32, our result seems to suggest that the trend of Ωm0\Omega_{m0} dependence for an evolving dark energy from a combination of the observational data sets is model-dependent.Comment: 16 pages, 15 figures, To appear in JCA

    Geometric phase outside a Schwarzschild black hole and the Hawking effect

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    We study the Hawking effect in terms of the geometric phase acquired by a two-level atom as a result of coupling to vacuum fluctuations outside a Schwarzschild black hole in a gedanken experiment. We treat the atom in interaction with a bath of fluctuating quantized massless scalar fields as an open quantum system, whose dynamics is governed by a master equation obtained by tracing over the field degrees of freedom. The nonunitary effects of this system are examined by analyzing the geometric phase for the Boulware, Unruh and Hartle-Hawking vacua respectively. We find, for all the three cases, that the geometric phase of the atom turns out to be affected by the space-time curvature which backscatters the vacuum field modes. In both the Unruh and Hartle-Hawking vacua, the geometric phase exhibits similar behaviors as if there were thermal radiation at the Hawking temperature from the black hole. So, a measurement of the change of the geometric phase as opposed to that in a flat space-time can in principle reveal the existence of the Hawking radiation.Comment: 14 pages, no figures, a typo in the References corrected, version to appear in JHEP. arXiv admin note: text overlap with arXiv:1109.033

    Brand Identity and Online Self-Customisation Usefulness Perception

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    Online self-customisation (OSC) enables customers to tailor their preferences to certain product features via a brand-hosted online platform. Recent literature has given increasing attention to how consumers value OSC. However, extant research is characterised by a scarcity of understanding the effects of brand identity and individual differences on consumer responses to OSC. The purpose of this paper is to examine the mediating role of trust and the moderating role of need for uniqueness on the effects of brand identity prestige and brand identity similarity on consumer perceived usefulness of OSC. A field survey, through mall intercept, was conducted to test this conceptual framework. Our findings advance this field by finding that, not only the brand identity and consumer need for uniqueness, but also the interaction between them may affect consumers’ evaluation of OSC

    Expression of CIAPIN1 in human colorectal cancer and its correlation with prognosis

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    <p>Abstract</p> <p>Background</p> <p>The cytokine-induced anti-apoptotic molecule (CIAPIN1) had been found to be a differentially-expressed gene involved in a variety of cancers, and it was also considered as a candidate tumour suppressor gene in gastric cancer, renal cancer and liver cancer. However, studies on the role of CIAPIN1 in colorectal cancer were still unavailable. The aim of this study was to determine the prognostic impact of CIAPIN1 in 273 colorectal cancer (CRC) samples and to investigate the CIAPIN1 expression in CRC cell lines after inducing differentiation.</p> <p>Methods</p> <p>Immunohistochemical analysis was performed to detect the expression of CIAPIN1 in CRC samples from 273 patients. The relationship between CIAPIN1 expression and patients' characteristics (gender, age, location of cancer, UICC stage, local recurrence and tumour grade factors) was evaluated. In addition, these patients were followed up for five consecutive years to investigate the relationship between CIAPIN1 expression and the prognosis of CRC. We induced the differentiation of the CRC cell lines HT29 and SW480, in order to detect the expression of CIAPIN1 in the process of CRC cells differentiation.</p> <p>Results</p> <p>Results indicated that CIAPIN1 was mainly expressed in the cytoplasm and nucleus, and that its expression level in cancer samples was significantly lower than in normal tissues. The Wilcoxon-Mann-Whitney test showed a significant difference in the differential expression of CIAPIN1 in patients with different T and UICC stages, and tumour grade (<it>P </it>= 0.0393, 0.0297 and 0.0397, respectively). The Kaplan-Meier survival analysis demonstrated that the survival time of CRC patients with high expression of CIAPIN1 was longer than those with low expression during the 5-year follow up period (<it>P </it>= 0.0002). COX regression analysis indicated that low expression of CIAPIN1, cancer stage of > pT1, distant organ metastasis (pM<sub>1</sub>), regional lymph node metastasis (> pN<sub>1</sub>) and local recurrence (yes) were independent, poor prognostic factors of CRC (<it>P </it>= 0.012, <it>P </it>= 0.032, <it>P <</it>0.001, <it>P <</it>0.001, <it>P <</it>0.001 respectively). Both Western blotting and RT-PCR showed that CIAPIN1 expression was increased with the degree of differentiation of HT29 and SW480 cells.</p> <p>Conclusions</p> <p>CIAPIN1 played an important role in the differentiation of CRC cells, and the differential expression of CIAPIN1 in CRC was closely related to prognosis.</p
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