5,820 research outputs found

    Iterative Multiuser Detection and Decoding with Spatially Coupled Interleaving

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    Spatially coupled (SC) interleaving is proposed to improve the performance of iterative multiuser detection and decoding (MUDD) for quasi-static fading multiple-input multiple-output systems. The linear minimum mean-squared error (LMMSE) demodulator is used to reduce the complexity and to avoid error propagation. Furthermore, sliding window MUDD is proposed to circumvent an increase of the decoding latency due to SC interleaving. Theoretical and numerical analyses show that SC interleaving can improve the performance of the iterative LMMSE MUDD for regular low-density parity-check codes.Comment: Long version of a paper submitted to IEEE Wireless Commun. Let

    Negative Correlation between the Diffusion Coefficient and Transcriptional Activity of the Glucocorticoid Receptor

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    The glucocorticoid receptor (GR) is a transcription factor, which interacts with DNA and other cofactors to regulate gene transcription. Binding to other partners in the cell nucleus alters the diffusion properties of GR. Raster image correlation spectroscopy (RICS) was applied to quantitatively characterize the diffusion properties of EGFP labeled human GR (EGFP-hGR) and its mutants in the cell nucleus. RICS is an image correlation technique that evaluates the spatial distribution of the diffusion coefficient as a diffusion map. Interestingly, we observed that the averaged diffusion coefficient of EGFP-hGR strongly and negatively correlated with its transcriptional activities in comparison to that of EGFP-hGR wild type and mutants with various transcriptional activities. This result suggests that the decreasing of the diffusion coefficient of hGR was reflected in the high-affinity binding to DNA. Moreover, the hyper-phosphorylation of hGR can enhance the transcriptional activity by reduction of the interaction between the hGR and the nuclear corepressors

    Esophageal Cancer Initially Thought to be Accompanied by a Solitary Metastasis to an Intrathoracic Paraaortic Lymph Node

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    Esophageal cancers usually exhibit lymph-node metastases. Although a solitary lymph-node metastasis is occasionally found, the involvement of an intrathoracic paraaortic node is rare. We present here an intrathoracic mid-esophageal cancer case in which an accompanying solitary retroaortic mass was found within the posterior mediastinum by integrated positron emission tomography/computed tomography. For diagnosis, thoracoscopic resection of the mass was performed from a left thoracic approach, and histology revealed it to be a squamous cell carcinoma metastasized from the esophageal cancer. Upon radical esophagectomy after neoadjuvant therapy as a T3N1M0 Stage IIIa (AJCC/UICC) cancer, the esophageal cancer was found to have invaded unexpectedly deeply in the vicinity of the descending aorta. Another lymph node within the paraaortic region was also involved (T4N1M0 Stage IIIc). The present case and other cases we review here inform our understanding of metastasis to intrathoracic paraaortic nodes as follows:1) its existence may indicate extensive lymph-node metastasis or direct tumor invasion nearby, and 2) it may be accompanied by other lymph-node involvements in this region, even if it appears solitary upon preoperative investigation. Thus, for radical esophagectomy, sufficient lymph-node dissection is required, even at locations not reached by the usual right thoracic approach. Definitive chemoradiotherapy may be a better choice for preoperatively recognized T3 esophageal cancer when the cancer is accompanied by paraaortic lymph node metastasis

    Sarcoidosis-associated hepatocellular carcinoma

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    Sarcoidosis is a systemic granulomatous inflammation of unknown etiology, and seems to involve the liver parenchyma in most cases. However, sarcoidosis-associated hepatocellular carcinoma is rare. We report here a case in which a hepatocellular carcinoma occurred within the liver, which was probably involved as a result of systemic sarcoidosis. A 57-year-old Japanese man had been followed up for 2 years because of diabetic nephropathy and sarcoidosis. On admission for pneumonia, imaging studies revealed an unexpected hepatic tumor. Histology revealed a hepatocellular carcinoma accompanied by T-lymphocytic infiltration and marked granulomatous inflammation, which was surrounding some tumor nodules. The background liver parenchyma exhibited a moderate degree of fibrosis with granulomatous inflammation. The patient had no other apparent liver disease such as viral hepatitis, steatohepatitis, or primary biliary cirrhosis. Therefore, in the present case, sarcoidosis may be considered the probable background etiology for hepatocarcinogenesis

    Fluidized bed combustor modeling

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    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested

    A Modified Real-Coded Genetic Algorithm Considering with Fitness-based Variability

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    A genetic algorithm (GA) is a search algorithm based on the mechanism of natural genetics. In various GAs, a real-coded GA (RCGA) employing individuals represented by real valued-genes has been proposed to solve the optimization problem in the continuous searching space. However, the conventional RCGA yields ineffective searches due to insufficient genetic diversity in the selection process. In this paper, we propose a modified RCGA with variability operator maintaining the genetic diversity of the population. In the proposed method, a variability term is newly added to the individuals selected by the ordinary selection. The degree of the variability is decided considering the fitness value of the individual. The searching performance of the proposed method is better than the conventional methods. The effectiveness and the validity of the proposed method are verified by applying it to optimization problems of continuous benchmark functions and signal sources localization

    Texture Classification Based on Complex Network Model with Spatial Information

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    This paper proposes a method for image texture classification based on a complex network model. Finding relevant and valuable information in an image texture is an essential issue for image classification and remains a challenge. Recently, a complex network model has been used for texture analysis and classification. However, with current analysis methods, important empirical properties of image texture such as spatial information are discarded from consideration. Accordingly, we propose local spatial pattern mapping (LSPM) method for manipulating the spatial information in an image texture with multi-radial distance analysis to capture the texture pattern. In experiments, the feature properties under the traditional complex network model and those with the proposed method are analyzed by using the Brodatz, UIUC, and Outex databases. As results, the proposed method is shown to be effective for texture classification, providing an improved classification rate as compared to the traditional complex network model

    Laboratory Simulation of the Effect of Rocket Thrust on a Precessing Space Vehicle

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    Ground tests of solid propellant rocket motors have shown that metal-containing propellants produce various amounts of slag (primarily aluminum oxide) which is trapped in the motor case, causing a loss of specific impulse. Although not yet definitely established, the presence of a liquid pool of slag also may contribute to nutational instabilities that have been observed with certain spin-stabilized, upper-stage vehicles. Because of the rocket's axial acceleration, absent in the ground tests, estimates of in-flight slag mass have been very uncertain. Yet such estimates are needed to determine the magnitude of the control authority of the systems required for eliminating the instability. A test rig with an eccentrically mounted hemispherical bowl was designed and built which incorporates a follower force that properly aligns the thrust vector along the axis of spin. A program that computes the motion of a point mass in the spinning and precessing bowl was written. Using various RPMs, friction factors, and initial starting conditions, plots were generated showing the trace of the point mass around the inside of the fuel tank. The apparatus will incorporate future design features such as a variable nutation angle and a film height measuring instrument. Data obtained on the nutational instability characteristics will be used to determine order of magnitude estimates of control authority needed to minimize the sloshing effect
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