1,952 research outputs found
BUILD PUBLIC TRUST THROUGH EXCELLENT SERVICE IN SCHOOL
This study aims to understand the implementation of excellent service in increasing public trust at SMA Nurul Jadid, Paiton, Probolinggo. This research uses a qualitative case study approach. The data collection technique is done through observation, interviews, and documentation. The data analysis technique was carried out through data reduction, data exposure, and concluding. The results showed that excellent service at SMA Nurul Jadid was implemented to increase public trust through; tangible modality, creating good communication, in-service training, the interconnection between employees, and an integrated approach to quality service. This research has implications for the importance of excellent service for every educational institution to ensure the loyalty of madrasa residents both internally and externally
Design and implementation of a novel three-phase cascaded half-bridge inverter
In this study, a new circuit topology of a three-phase half-bridge multilevel inverter (MLI) is proposed. The proposed MLI that consists of a cascaded half-bridge structure along with a modified full-bridge structure requires less number of dc-power supplies and power semiconductor devices, e.g. insulated gate bipolar transistors and diodes when compared with the existing MLI topologies, which significantly reduces the size and cost of the inverter. Two different structures: isolated and non-isolated dc-power supply-based three-phase half-bridge MLIs are investigated. A number of generalised methods are proposed to determine the magnitude of the input dc-power supplies that has a great impact on the number of levels of the output voltage waveform. To verify the feasibility of the proposed MLI topology, a scaled down laboratory prototype three-phase half-bridge MLI is developed and the experimental results are analysed and compared with the simulation results. Experimental and simulation results reveal the feasibility and excellent features of the proposed inverter system
Achalasia: unusual cause of chronic cough in children
Achalasia is a rare motility disorder of the esophagus which results from lack of enervation of the lower esophageal sphincter muscles and leads to dilatation of proximal esophagus. Patients with achalasia presents typically with dysphagia, vomiting of undigested food and failure to thrive. Cough can be present in achalasia patients due to aspiration of food or due to airway compression by the dilated esophagus. We report two cases of achalasia presenting primarily with prolonged cough. Diagnosis of achalasia in both cases was delayed due to this atypical presentation. This highlights the importance of recognizing achalasia as a potential cause of chronic cough in order to avoid delayed diagnosis and mismanagement
Sequential algorithm for life threatening cardiac pathologies detection based on mean signal strength and EMD functions
Abstract Background Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most serious cardiac arrhythmias that require quick and accurate detection to save lives. Automated external defibrillators (AEDs) have been developed to recognize these severe cardiac arrhythmias using complex algorithms inside it and determine if an electric shock should in fact be delivered to reset the cardiac rhythm and restore spontaneous circulation. Improving AED safety and efficacy by devising new algorithms which can more accurately distinguish shockable from non-shockable rhythms is a requirement of the present-day because of their uses in public places. Method In this paper, we propose a sequential detection algorithm to separate these severe cardiac pathologies from other arrhythmias based on the mean absolute value of the signal, certain low-order intrinsic mode functions (IMFs) of the Empirical Mode Decomposition (EMD) analysis of the signal and a heart rate determination technique. First, we propose a direct waveform quantification based approach to separate VT plus VF from other arrhythmias. The quantification of the electrocardiographic waveforms is made by calculating the mean absolute value of the signal, called the mean signal strength. Then we use the IMFs, which have higher degree of similarity with the VF in comparison to VT, to separate VF from VTVF signals. At the last stage, a simple rate determination technique is used to calculate the heart rate of VT signals and the amplitude of the VF signals is measured to separate the coarse VF from VF. After these three stages of sequential detection procedure, we recognize the two components of shockable rhythms separately. Results The efficacy of the proposed algorithm has been verified and compared with other existing algorithms, e.g., HILB 1, PSR 2, SPEC 3, TCI 4, Count 5, using the MIT-BIH Arrhythmia Database, Creighton University Ventricular Tachyarrhythmia Database and MIT-BIH Malignant Ventricular Arrhythmia Database. Four quality parameters (e.g., sensitivity, specificity, positive predictivity, and accuracy) were calculated to ascertain the quality of the proposed and other comparing algorithms. Comparative results have been presented on the identification of VTVF, VF and shockable rhythms (VF + VT above 180 bpm). Conclusions The results show significantly improved performance of the proposed EMD-based novel method as compared to other reported techniques in detecting the life threatening cardiac arrhythmias from a set of large databases.</p
Pattern of liver cysts with their surgical management
Background: Liver cysts are seen in up to 5% of the population. 15-16% of such cysts are symptomatic. Symptomatic cysts are found more commonly in women who are over 50 years of age.Simple hepatic cysts are believed to be congenital in origin.Methods: The observational study was conducted in the department of hepatobiliary department of surgery of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. Total of 80 cases were randomly selected for the study. Clinical examination and evaluation were done from July 2013 to June 2014. Proper consent was taken from the respective concern. Statistical analysis of the results was obtained by using window-based computer software statistical packages for social sciences (SPSS-22).Results: Most of the respondents were female (65%). The male-female ratio was 1:1.9. The mean age was 46.4 (±SD 10.191) years, ranging from 13-76 years. There were 69 non-parasitic diseases and 11 parasitic diseases. Among them 30 patients were diagnosed as liver cyst incidentally and they required no treatment. Liver function was abnormal in 70% patients. It was found from ultrasonography (USG) and computed tomography (CT) scan of abdomen that right lobe involvement (65% and 28% respectively) is more common than left lobe (21.3% and 12% respectively). The most common complication following surgical interventions was haemorrhage (32.4%).Conclusions: Females are affected most and M:F=1:1.9, usual affected age groups are of 5th decade and common in rural area. Imaging is the best modality for diagnosis of cystic lesions but serological investigations are also helpful
A Flood Risk Management Program of Wadi Baysh Dam on the Downstream Area: An Integration of Hydrologic and Hydraulic Models, Jizan Region, KSA
For public safety, especially for people who dwell in the valley that is located downstream of a dam site, as well as the protection of economic and environmental resources, risk management programs are urgently required all over the world. Despite the high safety standards of dams because of improved engineering and excellent construction in recent times, a zero-risk guarantee is not possible, and accidents can happen, triggered by natural hazards, human actions, or just because the dam is aging. In addition to that is the impact of potential climate change, which may not have been taken into account in the original design. A flood risk management program, which is essential for protecting downstream dam areas, is required. Part of this program is to prepare an inundation map to simulate the impact of dam failure on the downstream areas. The Baysh dam has crucial importance both to protect the downstream areas against flooding, to provide drinking water to cities in the surrounding areas, and to use the excess water for irrigation of the agricultural areas located downstream of the dam. Recently, the Kingdom of Saudi Arabia (KSA) was affected by extraordinary rainstorm events causing many problems in many different areas. One of these events happened along the basin of the Baysh dam, which raised the alarm to the decision makers and to the public to take suitable action before dam failure occurs. The current study deals with a flood risk analysis of Wadi Baysh using an integration of hydrologic and hydraulic models. A detailed field investigation of the dam site and the downstream areas down to the Red Sea coast has been undertaken. Three scenarios were applied to check the dam and the reservoir functionality; the first scenario at 100-and 200-year return period rainfall events, the second scenario according to the Probable Maximum Precipitation (PMP), and the third scenario if the dam fails. Our findings indicated that the Baysh dam and reservoir at 100-and 200-year rainfall events are adequate, however, at the PMP the water will spill out from the spillway at ~8900 m3/s causing flooding to the downstream areas; thus, a well-designed channel along the downstream wadi portion up to the Red Sea coast is required. However, at dam failure, the inundation model indicated that a vast area of the section downstream of the dam will be utterly devastated, causing a significant loss of lives and destruction of urban areas and agricultural lands. Eventually, an effective warning system and flood hazard management system are imperative
Direct Simulation Monte Carlo Analysis on Thrust Vectoring of a Supersonic Micro Nozzle using Bypass Mass Injection
Converging diverging micro nozzle is fundamentally intended for flow
acceleration through the generation of kinetic energy for the advanced
micro-propulsion systems. Such supersonic micro nozzles have significant
applications in the launching, propulsion and rapid directional control of the
micro-satellites for a better maneuver. Micro scale analysis of such flow
devices is extended to the rarefied flow regime. Present study has addressed
thrust vectoring in a planar converging-diverging supersonic micro nozzle by
the bypass mass injection technique. Direct Simulation Monte Carlo (DSMC)
method has been used for numerical modelling. Primary focus is given on the
thrust vectoring control of the micro nozzle with a throat height of 20 micro
meter and an expansion ratio of 1.7. For the secondary injection, a rectangular
channel of 5 different bypass widths (2 - 12 micro meter) is considered for two
different outlet pressures (Pout = 10 kPa and 40 kPa) while keeping the inlet
pressure (Pin) and temperature (Tin) fixed at 1 atm and 300 k respectively. The
physical behavior of the micro nozzle is acknowledged through the analysis of
Mach, pressure, temperature and density contours. Numerical results reveal that
the secondary flow injection is adapted into the primary flow through the
formation of a pressure bump in the diverging section. Moreover, the total mass
flow rate, secondary flow percentage, thrust force, the thrust coefficient and
specific impulse increase with the bypass channel width. A change in thrust
direction is obtained which in turn produces a considerable vectoring effect in
the supersonic micro nozzle. The vectoring angle for Pout of 40 kPa peaks at 6
micro meter bypass channel whereas a gradual increase of the vectoring angle
with the bypass channel width is observed for Pout = 10 kPa.Comment: Journal paper and it's under revie
Comparison of ring artifact removal methods using flat panel detector based CT images
<p>Abstract</p> <p>Background</p> <p>Ring artifacts are the concentric rings superimposed on the tomographic images often caused by the defective and insufficient calibrated detector elements as well as by the damaged scintillator crystals of the flat panel detector. It may be also generated by objects attenuating X-rays very differently in different projection direction. Ring artifact reduction techniques so far reported in the literature can be broadly classified into two groups. One category of the approaches is based on the sinogram processing also known as the pre-processing techniques and the other category of techniques perform processing on the 2-D reconstructed images, recognized as the post-processing techniques in the literature. The strength and weakness of these categories of approaches are yet to be explored from a common platform.</p> <p>Method</p> <p>In this paper, a comparative study of the two categories of ring artifact reduction techniques basically designed for the multi-slice CT instruments is presented from a common platform. For comparison, two representative algorithms from each of the two categories are selected from the published literature. A very recently reported state-of-the-art sinogram domain ring artifact correction method that classifies the ring artifacts according to their strength and then corrects the artifacts using class adaptive correction schemes is also included in this comparative study. The first sinogram domain correction method uses a wavelet based technique to detect the corrupted pixels and then using a simple linear interpolation technique estimates the responses of the bad pixels. The second sinogram based correction method performs all the filtering operations in the transform domain, i.e., in the wavelet and Fourier domain. On the other hand, the two post-processing based correction techniques actually operate on the polar transform domain of the reconstructed CT images. The first method extracts the ring artifact template vector using a homogeneity test and then corrects the CT images by subtracting the artifact template vector from the uncorrected images. The second post-processing based correction technique performs median and mean filtering on the reconstructed images to produce the corrected images.</p> <p>Results</p> <p>The performances of the comparing algorithms have been tested by using both quantitative and perceptual measures. For quantitative analysis, two different numerical performance indices are chosen. On the other hand, different types of artifact patterns, e.g., single/band ring, artifacts from defective and mis-calibrated detector elements, rings in highly structural object and also in hard object, rings from different flat-panel detectors are analyzed to perceptually investigate the strength and weakness of the five methods. An investigation has been also carried out to compare the efficacy of these algorithms in correcting the volume images from a cone beam CT with the parameters determined from one particular slice. Finally, the capability of each correction technique in retaining the image information (e.g., small object at the iso-center) accurately in the corrected CT image has been also tested.</p> <p>Conclusions</p> <p>The results show that the performances of the algorithms are limited and none is fully suitable for correcting different types of ring artifacts without introducing processing distortion to the image structure. To achieve the diagnostic quality of the corrected slices a combination of the two approaches (sinogram- and post-processing) can be used. Also the comparing methods are not suitable for correcting the volume images from a cone beam flat-panel detector based CT.</p
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