192 research outputs found

    Channel Characterization and Modeling for Future Wireless Communication Systems

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    Autonomous Development of Algorithmic Concepts for Program Comprehension

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    A developmental model of algorithmic concepts is proposed here for program comprehension. Unlike traditional approaches that cannot do anything beyond their predesigned representation, this model can develop its internal representation autonomously from chaos into algorithmic concepts by mimicking concept formation in the brain under an uncontrollable environment that consists of program source codes from the Internet. The developed concepts can be employed to identify what algorithm a program performs. The accuracy of such identification reached 97.15% in a given experiment

    Intracoronary Sarcoplasmic Reticulum CalciumATPase Gene Therapy in Advanced Heart Failure Patients with reduced Ejection Fraction: A Prospective Cohort Study

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    OBJECTIVE: Heart failure is a progressive and debilitating disease. Intracoronary sarcoplasmic reticulum calciumATPase gene therapy may improve the function of cardiac muscle cells. This study aimed to test the hypothesis that intracoronary sarcoplasmic reticulum calcium-ATPase gene therapy can improve outcomes and reduce the number of recurrent and terminal events in advanced heart failure patients with reduced ejection fraction. METHODS: A total of 768 heart failure patients with reduced ejection fraction and New York Heart Association classification II to IV were included in this prospective cohort study. Patients either underwent intracoronary sarcoplasmic reticulum calcium-ATPase gene therapy (CA group, n=384) or received oral placebo (PA group; n=384). Data regarding recurrent and terminal event(s), treatment-emergent adverse effects, and outcome measures were collected and analyzed. RESULTS: After a follow-up period of 18 months, intracoronary sarcoplasmic reticulum calcium-ATPase gene therapy reduced the number of hospital admissions (p=0.001), ambulatory treatments (p=0.0004), and deaths (p=0.024). Additionally, intracoronary sarcoplasmic reticulum calcium-ATPase gene therapy improved the left ventricular ejection fraction (po0.0001) and Kansas City Cardiomyopathy Questionnaire score (po0.0001). The number of recurrent and terminal events/patients were higher in the PA group than in the CA group after the follow-up period of 18 months (p=0.015). The effect of the intracoronary sarcoplasmic reticulum calciumATPase gene therapy was independent of the confounding variables. No new arrhythmias were reported in the CA group. CONCLUSIONS: Intracoronary sarcoplasmic reticulum calcium-ATPase gene therapy reduces the number of recurrent and terminal events and improves the clinical course of advanced heart failure patients with reduced ejection fraction

    A USRP-based Channel Sounder for UAV Communications

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    Tanshinone IIA suppress the proliferation of HNE-1 nasopharyngeal carcinoma an in vitro study

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    AbstractNasopharyngeal carcinoma (NPC) at present is considered to be one of the fatal diseases detected commonly in the people belonging to Southeast Asia and southern China. According to the WHO reports among the detected cases of NPC worldwide, 80% are from China. The present study investigates the effect of tanshinone IIA on the migration and invasion potential of HNE-1NPC cells and studied the detailed mechanism involved. Effect of the tanshinone IIA on viability of the HNE-1NPC cells was analyzed by MTS assay. Cell matrigel invasion and wound-healing motility assays, respectively were used for the analysis of invasion and migration potential of HNE-1 cells. Tanshinone IIA inhibited the viability of HNE-1cells in a dose dependent manner. Migration and invasion potential of the tanshinone IIA treated cells was reduced significantly (P<0.05) compared to the control cells after 48h. Analysis of the proteins involved in migration and invasion revealed a significant decrease in the expression of matrix metalloproteinase (MMP)-2 and MMP-9 on treatment with tanshinone IIA. It also inhibited the p65 and p50 expression in the nuclear fractions of HNE-1 cells after 48h. Thus, tanshinone IIA inhibits migration and invasion potential of the HNE-1NPC cells through reduction in the expression of matrix metalloproteinases. Therefore, tanshinone IIA can be used for the treatment of NPC

    Dynamic Channel Modeling for Indoor Millimeter-Wave Propagation Channels Based on Measurements

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    In this contribution, a recently conducted measurement campaign for indoor millimeter-wave propagation channels is introduced. A vector network analyzer (VNA)-based channel sounder was exploited to record the channel characteristics at the frequency band from 28-30 GHz. A virtual uniform circular array (UCA) with a radius of 0.25m was formed using a rotator with 360 steps. Moreover, by taking advantage of fiber-optic technique applied in the channel sounder, measurements at 50 positions were performed from an indoor hall to an indoor corridor along a long pre-defined route. A low-complexity highresolution propagation estimation (HRPE) algorithm is exploited to estimate the propagation parameters of multipath components (MPCs). Based on the HRPE estimation results, a novel clustering identification and tracking algorithm is proposed to trace clusters. Composite channel characteristics, cluster-level characteristics and dynamic (or birth-death) behaviours of the clusters are investigated, which constitute a dynamic model for the indoor millimeter-wave channel

    Geometry-Based Clustering Characteristics for Outdoor Measurements at 28-30 GHz

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    This paper presents an analysis of channel characteristics for an outdoor scenario at the frequency band of 28-30 GHz. A geometry-based clustering algorithm is proposed to group the measured multipath components (MPCs) based on the interaction points on the surrounding walls or objects obtained from Ray Tracing 3-D simulations, which is more physically interpretable than the traditional clustering algorithm. The cluster-level characteristics at a total of 15 positions along a pre-defined route covering both line-of-sight (LoS) and non-LoS (NLoS) scenarios are investigated. Moreover, power contributions of MPCs with multiple bounces (up to 7 bounces in NLoS condition) from the interaction objects (IOs) are also investigated

    A Scatterer Localization Method Using Large-Scale Antenna Array Systems

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    As ultra-massive multiple-input multiple-output (UM-MIMO) has emerged as a key technology for millimeter-wave and terahertz communications, the spherical wave propagation should be considered for channel modeling. Therefore, it is critical to identify the locations and evolving behaviors of scatterers, i.e., the sources of the spherical wavefronts. In this contribution, a novel space-alternating generalized expectation-maximization (SAGE) based scatterer localization algorithm is proposed, where a large-scale antenna array is divided into multiple sub-arrays. Due to the decreased aperture of each sub-array, plane wave assumption can be applied to estimate the angles of departure/arrival, delays and amplitudes of multipath components (MPCs). Based on the angle variations of MPCs observed at different sub-arrays, the corresponding scatterers can be located. The proposed algorithm is verified in a simulation using a large-scale uniform circular array (UCA) system. Moreover, we apply this algorithm to an indoor measurement campaign conducted at 27-29\,GHz in a hall scenario. Dominant scatterers are identified, which can be used for the development of further geometry-based stochastic channel models

    Experimental Characterization of Millimeter-wave Indoor Propagation Channels at 28 GHz

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