2,948 research outputs found

    Hybrid Spam Filtering for Mobile Communication

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    Spam messages are an increasing threat to mobile communication. Several mitigation techniques have been proposed, including white and black listing, challenge-response and content-based filtering. However, none are perfect and it makes sense to use a combination rather than just one. We propose an anti-spam framework based on the hybrid of content-based filtering and challenge-response. There is the trade-offs between accuracy of anti-spam classifiers and the communication overhead. Experimental results show how, depending on the proportion of spam messages, different filtering %%@ parameters should be set.Comment: 6 pages, 5 figures, 1 tabl

    Observation of a strongly ferromagnetic spinor Bose-Einstein condensate

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    We report the observation of strongly ferromagnetic F=1F=1 spinor Bose-Einstein condensates of 7^7Li atoms. The condensates are generated in an optical dipole trap without using magnetic Feshbach resonances, so that the condensates have internal spin degrees of freedom. Studying the non-equilibrium spin dynamics, we have measured the ferromagnetic spin interaction energy and determined the ss-wave scattering length difference among total spin ff channels to be af=2af=0=18(3)a_{f=2}-a_{f=0} =-18(3) Bohr radius. This strong collision-channel dependence leads to a large variation in the condensate size with different spin composition. We were able to excite a radial monopole mode after a spin-flip transition between the mF=0|m_F=0\rangle and mF=1|m_F=1\rangle spin states. From the experiments, we estimated the scattering length ratio af=2/af=0=0.27(6)a_{f=2}/a_{f=0}=0.27(6), and determined af=2a_{f=2} = 7(2) and af=0a_{f=0} = 25(5) Bohr radii, respectively. The results indicate the spin-dependent interaction energy of our system is as large as 46%\% of the condensate chemical potential

    Emission of Spin-correlated Matter-wave Jets from Spinor Bose-Einstein Condensates

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    We report the observation of matter-wave jet emission in a strongly ferromagnetic spinor Bose-Einstein condensate of 7^7Li atoms. Directional atomic beams with F=1,mF=1|{F=1,m_F=1}\rangle and F=1,mF=1|{F=1,m_F=-1}\rangle spin states are generated from F=1,mF=0|{F=1,m_F=0}\rangle state condensates, or vice versa. This results from collective spin-mixing scattering events, where spontaneously produced pairs of atoms with opposite momentum facilitates additional spin-mixing collisions as they pass through the condensates. The matter-wave jets of different spin states (F=1,mF=±1|{F=1,m_F=\pm1}\rangle) can be a macroscopic Einstein-Podolsky-Rosen state with spacelike separation. Its spin-momentum correlations are studied by using the angular correlation function for each spin state. Rotating the spin axis, the inter-spin and intra-spin momentum correlation peaks display a high contrast oscillation, indicating collective coherence of the atomic ensembles. We provide numerical calculations that describe the experimental results at a quantitative level and can identify its entanglement after 100~ms of a long time-of-flight.Comment: 13 pages(6 main text, 7 supplemental material), 12 figure

    Development of a University-Based Simplified H₂O₂/PE Hybrid Sounding Rocket at KAIST

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    Heterogeneity of Adenosine Triphosphate-Based Chemotherapy Response Assay in Colorectal Cancer - Secondary Publication

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    PURPOSE: Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is a well-documented and validated technology that can individualize chemotherapy for patients with lung, stomach, or breast cancer. This study explored the feasibility of ATP-CRA as a chemosensitivity test in patients with colorectal cancer. MATERIALS AND METHODS: A total of 118 patients who underwent surgical resection for colorectal adenocarcinoma were analyzed for chemosensitivity to 6 anticancer drugs using ATP-CRA. We calculated the cell death rate (CDR) by measuring intracellular ATP levels of drug-exposed cells and untreated controls. RESULTS: Interpretable results were available for 85.5% (118/138) of patients. The mean coefficient of variation for triplicate ATP measurements was 9.2%. The highest CDR was observed in irinotecan (34.0%) and the lowest CDR in etoposide (21.0%). Paclitaxel had the broadest range of CDR (0-86.7%) and 5-FU had the narrowest range of CDR (0-56.8%). The overall highest responsiveness was seen most prevalently in irinotecan (24.7%, 23/93 patients). Irinotecan had the greatest responsiveness in patients with well differentiated and moderately differentiated carcinoma. CONCLUSION: Our study suggests that ATP-CRA could be used to identify patients with colorectal cancer who might benefit from treatment with a specific chemotherapeutic agent.ope

    Failure Elongation of Steel Sheets for an Autobody at the High Strain Rate

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    This paper presents the dynamic failure elongation of conventional mild steels and advanced high strength steel sheets such as TRIP and DP steels. The failure elongation has been obtained from the high speed tensile testing machine with various strain rates ranged from 0.003/s to 200/s. The experimental result demonstrates that the tensile elongation does not simply decrease as the strain rate increases, but it decreases from the quasi-static state to the strain rate of 0.1 or 1/s and increases again up to the strain rate of 100/s. Furthermore, some high strength steels have the tendency that the tensile elongation increases as the strain rate increases. This tendency has varieties depending on the microstructure and forming history of sheet metal. Moreover, the localized strain rate hardening in the necking region induces the increase of elongation. This phenomenon is very important not only in sheet metal forming but also in the crashworthiness evaluation to predict the fracture of sheet metal members

    Classifying the universal coarsening dynamics of a quenched ferromagnetic condensate

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    Scale invariance and self-similarity in physics provide a unified framework to classify phases of matter and dynamical properties of near-equilibrium systems. However, extending this framework to far-from-equilibrium quantum many-body systems and categorizing their dynamics have remained a major challenge in physics. Here, we report on the first classification of universal coarsening dynamics in a quenched two-dimensional ferromagnetic spinor Bose gas. We observe spatiotemporal scaling of spin correlation functions with distinguishable scaling exponents, 1/z=0.58(2)1/z=0.58(2) and 1/z=0.43(2)1/z=0.43(2), characteristic, respectively, of binary and diffusive fluids. We find the universality class of the coarsening dynamics are determined by the symmetry of the order parameters and the annihilation dynamics of the topological defects. These observations are in excellent agreement with many-body simulations. Our results represent a paradigmatic example of categorizing far-from-equilibrium dynamics in quantum many-body systems.Comment: 7 pages, 5 figures, and supplemental material
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