1,403 research outputs found

    I/Q Regeneration Algorithm for Direct Conversion Receiver Using 5-Port Junction

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    Abstract-We introduce a reliable I/Q regeneration algorithm for digital video broadcasting system (DVB-S) using a 5-port junction direct conversion receiver. The DVB-S uses two modulation schemes; QPSK and 8PSK. We propose two cost functions for each modulation scheme. The proposed algorithm utilizes the charateristic of the modulated symbol, so it simplifies the phase-offset compensation problem with low complexity. Simulation results show that bit error rate (BER) of the proposed scheme agrees very well with the theoretical BER for QPSK and 8PSK

    Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System

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    This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM) systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN) was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms

    Electric field control of nonvolatile four-state magnetization at room temperature

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    We find the realization of large converse magnetoelectric (ME) effects at room temperature in a multiferroic hexaferrite Ba0.52_{0.52}Sr2.48_{2.48}Co2_{2}Fe24_{24}O41_{41} single crystal, in which rapid change of electric polarization in low magnetic fields (about 5 mT) is coined to a large ME susceptibility of 3200 ps/m. The modulation of magnetization then reaches up to 0.62 μ\muB_{B}/f.u. in an electric field of 1.14 MV/m. We find further that four ME states induced by different ME poling exhibit unique, nonvolatile magnetization versus electric field curves, which can be approximately described by an effective free energy with a distinct set of ME coefficients

    Factors of quality of care and their association with smartphone based PHR adoption in South Korean hospitals

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    Background Healthcare organizations have begun to adopt personal health records (PHR) systems to engage patients, but little is known about factors associated with the adoption of PHR systems at an organizational level. The objective of this study is to investigate factors associated with healthcare organizations’ adoption of PHR systems in South Korea. Methods The units of analysis were hospitals with more than 100 beds. Study data of 313 hospitals were collected from May 1 to June 30, 2020. The PHR adoption status for each hospital was collected from PHR vendors and online searches. Adoption was then confirmed by downloading the hospital’s PHR app and the PHR app was examined to ascertain its available functions. One major outcome variable was PHR adoption status at hospital level. Data were analysed by logistic regressions using SAS 9.4 version. Results Out of 313 hospitals, 103 (32.9%) hospitals adopted PHR systems. The nurse-patient ratio was significantly associated with PHR adoption (OR 0.758; 0.624 to 0.920, p = 0.005). The number of health information management staff was associated with PHR adoption (OR 1.622; 1.228 to 2.141, p = 0.001). The number of CTs was positively associated with PHR adoption (OR 5.346; 1.962 to 14.568, p = 0.001). Among the hospital characteristics, the number of beds was significantly related with PHR adoption in the model of standard of nursing care (OR 1.003; 1.001 to 1.005, p < 0.001), HIM staff (OR 1.004; 1.002 to 1.006, p < 0.001), and technological infrastructure (OR 1.050; 1.003 to 1.006, p < 0.001). Conclusions One-third of study hospitals had adopted PHR systems. Standard of nursing care as well as information technology infrastructure in terms of human resources for health information management and advanced technologies were significantly associated with adoption of PHR systems. A favourable environment for adopting new technologies in general may be associated with the adoption and use of PHR systems.This study was supported for two years by a Pusan National University Research Grant

    A Novel Technique of Morcellation Using a Pneumovesicum After Holmium Laser Enucleation of the Prostate in Complicated Situations: Our Initial Experience and Tips

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    Purpose To describe our initial experience with a novel method of adenoma retrieval using a pneumovesicum (PNV) after Holmium laser enucleation of the prostate (HoLEP). Methods From January 2016 to April 2018, a total of 93 consecutive patients treated with HoLEP were enrolled in this study. For tissue morcellation, we used the PNV morcellation technique for an initial series of 21 patients and the conventional technique (Lumenis VersaCut) for a consecutive series of 72 patients. We compared efficiency and safety between the novel technique and the traditional technique. Subgroup analysis was performed to assess the effectiveness of the current technique in the large prostate (>70 mL). Results There were significant differences in mean age and prostate volume between the 2 groups. However, there were no significant differences in the baseline characteristics and preoperative parameters in the subgroup analysis of large prostates (>70 mL). The mean morcellation efficiency was higher (8.50±1.94 minutes vs. 1.76±0.45 minutes, P<0.05) and the time of morcellation (7.81±1.25 minutes vs. 34.04±11.14 minutes, P<0.05) was shorter in the PNV group. Moreover, there were no significant differences between groups in hospitalization period (2.62±1.10 days vs. 2.90±1.26 days, P=0.852) and any other postoperative events, including recatheterization, reoperation, clot retention, and urethral stricture (P-value range, 0.194–0.447). In the PNV group, there were some cases of procedure-related complications, including postoperative extravesical leakage (5th case), clot retention (8th case), and recatheterization (9th case). Conclusions This method has a higher tissue retrieval efficacy, with the advantage of excellent visibility compared to conventional morcellation. The current method can be applied when a transurethral morcellator is out of order or cannot be used

    Cecal Polypoid Arteriovenous Malformations Removed by Endoscopic Biopsy

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    Colonic arteriovenous malformation (AVM) is one of the causes of lower gastrointestinal bleeding. Unlike small vascular ectasia or angiodysplasia, colonic AVM tends to be solitary, large in size, and identified endoscopically as flat or elevated bright red lesion. Herein, we report a case of non-solitary and small cecal AVMs which were removed by endoscopic biopsy. A 66-yr-old woman was referred for routine gastrointestinal cancer screening. She was suffering from diabetes, hypertension, end-stage renal disease, and anemia of chronic disease. On colonoscopic finding, three semi-pedunculated polyps, less than 5 mm in size, were noticed near to the appendiceal orifice. Since the lesions revealed normal-looking epithelium with converging folds on the cecal base, lesions were diagnosed as inflammatory polyps on gross finding. Three biopsies were taken from each lesion. Bleeding from the biopsied site ceased spontaneously. Histopathologic evaluation demonstrated intramucosal hemorrhage and dilated submucosal vessels which were consistent with polypoid colonic AVMs

    Effect of heat treatment and drawing on high-manganese steel pipe welded by gas tungsten arc

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    This study investigated the effect of post-weld processes including annealing and drawing on the microstructure and mechanical properties of high-Mn steel pipes welded by gas tungsten arc welding. The weld metal showed a solidified microstructure having coarse and elongated grains due to coalescence of columnar dendrite into welding heat direction. After post-annealing, the solidified microstructure changed into equiaxed grains due to recrystallization and grain growth. Mn segregation occurred during welding solidification and caused lower stacking fault energy (SFE) in the Mn-depleted region. Although epsilon-martensite formation in the as-welded state and during deformation was expected due to decreased SFE of the Mn-depleted zone, all regions showed a fully austenitic phase. The annealing process decreased strength due to grain coarsening but increased ductility. The drawing process increased strength of weld metal through work hardening. All pipes showed decreasing strain rate sensitivity (SRS) with deformation and negative SRS after certain strain levels. It was confirmed that negative SRS is related to less formation of mechanical twinning at a higher strain rate. This work provides fundamental insights into manufacturing a high-Mn steel pipe and manipulating its properties with annealing and drawing processes
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