Evaluating tag-based information access in image collections

The availability of social tags has greatly enhanced access to information. Tag clouds have emerged as a new "social" way to find and visualize information, providing both one-click access to information and a snapshot of the "aboutness" of a tagged collection. A range of research projects explored and compared different tag artifacts for information access ranging from regular tag clouds to tag hierarchies. At the same time, there is a lack of user studies that compare the effectiveness of different types of tag-based browsing interfaces from the users point of view. This paper contributes to the research on tag-based information access by presenting a controlled user study that compared three types of tag-based interfaces on two recognized types of search tasks - lookup and exploratory search. Our results demonstrate that tag-based browsing interfaces significantly outperform traditional search interfaces in both performance and user satisfaction. At the same time, the differences between the two types of tag-based browsing interfaces explored in our study are not as clear. Copyright 2012 ACM

Robust Design for Amplify-and-Forward MIMO Relay Systems with Direct Link and Imperfect Channel Information

In this paper, we propose statistically robust design for multiple-input multiple-output (MIMO) relay systems with the direct source-destination link and imperfect channel state information (CSI). The minimum mean-squared error (MMSE) of the signal waveform estimation at the destination node is adopted as the design criterion. We develop two iterative methods to solve the nonconvex joint source, relay, and receiver optimization problem. In particular, we derive the structure of the optimal relay precoding matrix and show the effect of CSI mismatch on the structure of the optimal robust source and relay matrices. The proposed algorithms generalize the transceiver design of MIMO relay systems with the direct link to the practical scenario of imperfect CSI knowledge. Simulation results demonstrate an improved performance of the proposed algorithms with respect to the conventional methods at various levels of CSI mismatch

Observation of large intrinsic anomalous Hall conductivity in polycrystalline Mn3_3Sn films

We report the observation of anomalous Hall effect in Mn$_3$Sn polycrystalline thin films deposited on Pt coated Al$_2$O$_3$ substrate with a large anomalous Hall conductivity of 65($\Omega$cm)$^{-1}$ at 3K. The Hall and magnetic measurements show a very small hysteresis owing to a weak ferromagnetic moment in this material. The longitudinal resistivity decreases sufficiently for the thin films as compared to the polycrystalline bulk sample used as the target for the film deposition. The anomalous Hall resistivity and conductivity decreases almost linearly with the increase in the temperature. A negative magnetoresistance is observed for all the measured temperatures with the negative decrease in the magnitude with the increase in temperature

New Results on Transceiver Design for Two-Hop Amplify-and-Forward MIMO Relay Systems With Direct Link

© 2016 IEEE. Conventional amplify-and-forward (AF) protocol for half-duplex two-hop multiple-input-multiple-output (MIMO) relay systems assumes that the source node transmits the signal only at the first time slot. While making the source node silent at the second time slot simplifies the system design, it is strictly suboptimal. To improve the system performance, in this paper, we consider that the source node transmits signals during both time slots. We develop two novel iterative algorithms to optimize the source, relay, and receiver matrices in this new AF MIMO relay system. Both algorithms are based on the minimum mean-square error (MMSE) criterion. In particular, the first algorithm is applicable for general MIMO relay systems with multiple concurrent data streams, where the source, relay, and receiver matrices are optimized in an alternating fashion until convergence. The second algorithm is developed for MIMO relay systems with a single data stream, where the source precoding vectors and the relay precoding matrix are optimized iteratively and the receiver matrix is obtained after the convergence of the source vectors and the relay matrix. Simulation results show that compared with conventional AF MIMO relay systems, the proposed system provides better bit-error-rate performance for both multiple-data-stream and single-data-stream cases

Associated production of the charged Higgs boson and single top quark at the LHC

The left-right twin Higgs(LRTH) model predicts the existence of the charged Higgs $\phi^{\pm}$. In this paper, we study the production of the charged Higgs boson $\phi^{-}$ with single top quark via the process $bg\to t\phi^{-}$ at the $CERN$ Large Hadron Collider(LHC). The numerical results show that the production cross section can reach the level of $10 pb$ in the reasonable parameter space of the LRTH model. We expect that, as long as it is not too heavy, the possible signatures of the heavy charged Higgs boson $\phi^{-}$ might be detected via the decay mode $\phi^{-}\to \bar{t}b$ at the LHC experiments.Comment: This paper has been withdrawn by the author(s) due to some mistakes in this pape

Thermal stability of ultrahard polycrystalline diamond composite materials

Thermal stability of the ultrahard polycrystalline diamond (UHPCD) composite material developed by the reinforcement of the polycrystalline diamond (PCD) with chemical vapor deposition (CVD) diamond has been investigated in a flow of argon at 1200 °C. The indentation, Raman spectra and wear test have been performed to compare hardness, C–C structure and wear resistance of untreated and thermal treated UHPCD. It has been shown that the hardness of CVD diamond in UHPCD attains 133±7 GPa after high pressure and high temperature, while after thermal treatment the hardness decreases to 109±3 GPa, and the wear resistance of the thermal treated UHPCD decreases from 0.17 to 0.6 mg/km. The narrowing of full width at half maximum and shift of Raman peak to lower frequencies of CVD diamond in thermal treated UHPCD imply a decrease of crystal structural defects and compressive stresses, which results in a drop of the hardness of CVD diamond in a thermal treated UHPCD. The higher wear rate of thermal treated UHPCD is due to the lower hardness.Досліджено термічну стабільність надтвердого полікристалічного алмазного (UHPCD) композиційного матеріалу, отриманого армуванням полікристалічного алмазу після хімічного осадження (CVD) алмазу в потоці аргону при 1200 °C. Для порівняння твердості, C–C-структури і зносостійкості необробленого та термообробленого UHPCD було досліджено заглиблення індентора, спектри комбінаційного розсіювання та знос. Показано, що твердість CVD-алмазу в UHPCD досягає 133±7 ГПа після дії високого тиску і високої температури, а після термообробки зменшується до 109±3 ГПа, зносостійкість UHPCD після термообробки зменшується від 0,17 до 0,6 мг/км. Звуження напівширини і зсув піку комбінаційного розсіювання в область низьких частот CVD-алмазу в термообробленому UHPCD характеризує зменшення кристалічних структурних дефектів і напружень стиску, що призводить до зниження твердості CVD-алмазу в термообробленому UHPCD. Вища швидкість зносу термообробленого UHPCD пов’язана з більш низькою твердістю.Исследована термическая стабильность сверхтвердого поликристаллического алмазного (UHPCD) композиционного материала, полученного армированием поликристаллического алмаза после химического осаждения (CVD) алмаза в потоке аргона при 1200 °C. Для сравнения твердости, C–C-структуры и износостойкости необработанного и термообработанного UHPCD были исследованы глубина проникновения индентора, спектры комбинационного рассеяния и износ. Показано, что твердость CVD-алмаза в UHPCD достигает 133±7 ГПа после действия высокого давления и высокой температуры, а после термической обработки уменьшается до 109±3 ГПа, износостойкость после термической обработки UHPCD уменьшается от 0,17 до 0,6 мг/км. Сужение полуширины и сдвиг пика комбинационного рассеяния в область низких частот CVD- алмаза в термообработанном UHPCD характеризует уменьшение кристаллических структурных дефектов и напряжений сжатия, что приводит к снижению твердости CVD-алмаза в термообработанном UHPCD. Более высокая скорость износа термически обработанного UHPCD связана с более низкой твердостью

Research on human placenta-derived mesenchymal stem cells transfected with pIRES2-EGFP-VEGF165 using liposome

The experiment adopting reverse transcription polymerase chain reaction (RT-PCR) technology, amplified hVEGF165 gene fragments from human leukemia cells HL-60. hVEGF165 gene was reconstructed in pIRES2-EGFP and transferred into the human placenta-derived mesenchymal stem cells (HPMSCs) by liposome-mediated method successfully. The mRNA and protein of hVEGF165 in the transferred cells was detected by RT-PCR and Western blot, and the results showed that hVEGF165mRNA and the protein expressed by HPMSCs transfected with pIRES2-EGFP-hVEGF165 was significantly more than HPMSCs transfected with pIRES2-EGFP. EGFP expression was observed under fluorescence microscope, which proved that the report gene was successfully transferred to the target cells. hVEGF biology activity and cell proliferation activity of HPMSCS transfected with pIRES2-EGFPhVEGF165 was detected by MTT array, which showed that hVEGF165 can promote the proliferation of HPMSCS; however, hVEGF165 biology activity of HPMSCS transfected with pIRES2-EGFP-hVEGF165 was significantly more than HPMSCs transfected with pIRES2-EGFP.  Identification of multipotentiality showed that HPMSCS transfected with pIRES2-EGFP-VEGF165 still maintained multipotentiality.Key words: Transfect, human placenta-derived mesenchymal stem cells, hVEGF165

Optimal Source and Relay Design for Multiuser MIMO AF Relay Communication Systems with Direct Links and Imperfect Channel Information

In this paper, we propose statistically robust design for multiuser multiple-input multiple-output (MIMO) relay systems with direct source-destination links and imperfect channel state information (CSI). The minimum mean-squared error (MMSE) of the signal waveform estimation at the destination node is adopted as the design criterion. We develop two iterative methods to solve the nonconvex joint source, relay, and receiver optimization problem. Simulation results demonstrate the improved robustness of the proposed algorithms against CSI errors