1,682 research outputs found

    Airline service quality ranking based on TOPSIS-VIKOR-AISM

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    The service quality ranking of airlines is a crucial factor for their sustainability in the intensely competitive airline market. This study intends to offer further insights in this field to produce simpler and explanatory results, however previous studies have been lacking in terms of sample size, efficiency, and reliability. In order to develop an airline service quality evaluation system that incorporates customer utilities, ideal points, and regret values and performs a confrontation hierarchy topology analysis based on the computation of compromise solutions, the TOPSIS-VIKOR-AISM model is proposed in this work. In addition to supporting consumer choice and airline development, this study offers fresh perspectives on how to assess the effectiveness of airlines and other industries

    Coronary Computed Tomography Angiography—A Promising Imaging Modality in Diagnosing Coronary Artery Disease

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    BackgroundTraditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.MethodsCoronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 ±11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.ResultsAll CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.ConclusionThe 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments. [J Chin Med Assoc 2008;71(5):241–246

    Intravitreous injection of Lucentis combined with argon laser photocoagulation for treatment of retinal macroaneurysm

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    AIM: To evaluate the clinical efficacy of intravitreous injection of Lucentis combined with argon laser photocoagulation on retinal macroaneurysm.<p>METHODS: A retrospective observation about intravitreous injection of Lucentis combined with argon laser photocoagulation was performed on 9 patients(9 eyes)with retinal macroaneurysms with macular edema between January 2011 and July 2013. Through the collection of clinical data in patients best-corrected visual acuity, change of the retinal macroaneurysm, optical coherence tomography and fluoresce in fundus angiography before therapy and 1 mouth,3 mouths after therapy, comparative analysis the changes in best-corrected visual acuity and central macular retinal thickness(CMT)between before and after treatment.<p>RESULTS: Followed for more than 3 months, all patients' best-corrected visual acuity were improved obviously, the difference was significant(<i>P</i><0.05); The patients' macular edema was obviously absorbed and the average CMT was significantly lower, the difference was significant(<i>P</i><0.05). In fundus fluorescein angiography, the neoplasia body was atrophied inordinately after 3 months of treatment.<p>CONCLUSION:Intravitreous injection of Lucentis combined with argon laser photocoagulation is effective and security to improving visual acuity of retinal macroaneurysms with macular edema

    Structural phase transitions of vortex matter in an optical lattice

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    We consider the vortex structure of a rapidly rotating trapped atomic Bose-Einstein condensate in the presence of a co-rotating periodic optical lattice potential. We observe a rich variety of structural phases which reflect the interplay of the vortex-vortex and vortex-lattice interactions. The lattice structure is very sensitive to the ratio of vortices to pinning sites and we observe structural phase transitions and domain formation as this ratio is varied.Comment: 4 pages, 3 figure

    Efficient CT Metal Artifact Reduction Based on Fractional-Order Curvature Diffusion

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    We propose a novel metal artifact reduction method based on a fractional-order curvature driven diffusion model for X-ray computed tomography. Our method treats projection data with metal regions as a damaged image and uses the fractional-order curvature-driven diffusion model to recover the lost information caused by the metal region. The numerical scheme for our method is also analyzed. We use the peak signal-to-noise ratio as a reference measure. The simulation results demonstrate that our method achieves better performance than existing projection interpolation methods, including linear interpolation and total variation

    Effect of dry-wet cycles on dynamic properties and microstructures of sandstone: Experiments and modelling

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    Underground pumped storage power plant (UPSP) is an innovative concept for space recycling of abandoned mines. Its realization requires better understanding of the dynamic performance and durability of reservoir rock. This paper conducted ultrasonic detection, split Hopkinson pressure bar (SHPB) impact, mercury intrusion porosimetry (MIP), and backscatter electron observation (BSE) tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage. A coupling FEM-DEM model was constructed for reappearing mesoscopic structure damage. The results show that dry-wet cycles decrease the dynamic compressive strength (DCS) with a maximum reduction of 39.40%, the elastic limit strength is reduced from 41.75 to 25.62 MPa. The sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock particle. The pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles, which verifies the computational statistics analysis of particle deterioration. The numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are dominant. The dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields
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