A dual adaptive watermarking scheme in contourlet domain for DICOM images

<p>Abstract</p> <p>Background</p> <p>Nowadays, medical imaging equipments produce digital form of medical images. In a modern health care environment, new systems such as PACS (picture archiving and communication systems), use the digital form of medical image too. The digital form of medical images has lots of advantages over its analog form such as ease in storage and transmission. Medical images in digital form must be stored in a secured environment to preserve patient privacy. It is also important to detect modifications on the image. These objectives are obtained by watermarking in medical image.</p> <p>Methods</p> <p>In this paper, we present a dual and oblivious (blind) watermarking scheme in the contourlet domain. Because of importance of ROI (region of interest) in interpretation by medical doctors rather than RONI (region of non-interest), we propose an adaptive dual watermarking scheme with different embedding strength in ROI and RONI. We embed watermark bits in singular value vectors of the embedded blocks within lowpass subband in contourlet domain.</p> <p>Results</p> <p>The values of PSNR (peak signal-to-noise ratio) and SSIM (structural similarity measure) index of ROI for proposed DICOM (digital imaging and communications in medicine) images in this paper are respectively larger than 64 and 0.997. These values confirm that our algorithm has good transparency. Because of different embedding strength, BER (bit error rate) values of signature watermark are less than BER values of caption watermark. Our results show that watermarked images in contourlet domain have greater robustness against attacks than wavelet domain. In addition, the qualitative analysis of our method shows it has good invisibility.</p> <p>Conclusions</p> <p>The proposed contourlet-based watermarking algorithm in this paper uses an automatically selection for ROI and embeds the watermark in the singular values of contourlet subbands that makes the algorithm more efficient, and robust against noise attacks than other transform domains. The embedded watermark bits can be extracted without the original image, the proposed method has high PSNR and SSIM, and the watermarked image has high transparency and can still conform to the DICOM format.</p

New Model Reference Adaptive System Speed Observer for Field-Oriented Control Induction Motor Drives Using Neural Networks

One of the primary advantages of field-oriented controlled induction motor for high performance application is the capability for easy field weakening and the full utilization of voltage and current rating of the inverter to obtain a wide dynamic speed rangeThis paper describes a Model Reference Adaptive System (MRAS) based scheme using Artificial Neural Network (ANN) for online speed estimation of sensorless vector controlled induction motor drive. The proposed MRAS speed observer uses the current model as an adaptive model. The neural network has been then designed and trained online by employing a back propagation network (BPN) algorithm. The estimator was designed and simulated in Matlab/Simulink. Simulation result shows a good performance of speed estimator. The simulation results show good performance in various operating conditions. Also Performance analysis of speed estimator with the change in resistances of stator is presented. Simulation results show this estimator robust to parameter variations especially resistances of stator

Nursing Students' Viewpoints on Teacher Evaluation in Urmia University of Medical Sciences, Iran: Content Analysis

Introduction: Teachers are among the most important parts of the education system and have an important role in achieving educational goals. Teachers evaluation and assessing the quality of their work is one of the most important aspects of improving the quality of education. Thus, the aim of this study was to evaluate viewpoints of nursing students on teachers evaluation. Method: This was a qualitative study conducted on 14 nursing students from the Urmia University of Medical Sciences, Iran. Participants were selected through purposive sampling and informed consent was obtained. Data were collected through conducting deep and semi-structured interviews, presence in the field and taking handwritten notes. All interviews were recorded, transcribed, and reviewed on paper. Data were analyzed using inductive approaches and content analysis. Results: Three main themes and 13 subthemes emerged about factors accefting teacher evaluation that included the evaluation process (inefficient questions, time, distribution of questionnaires and explanations), functional characteristics of the students (trueness, awareness, integrity, inclusion of personal feelings) and student view (experience of previous encounters, positive, and negative evaluation). Conclusion: Evaluation is endorsing effective activities and procedures and eliminating or weakening the ineffective or undesirable activities and methods. Based on the results of this study, the assessment process should be changed and the current evaluation process should be corrected to improve the quality of teachers’ work in order to positively impact students’ learning. Keywords: Evaluation, Teacher, Nursing student, Qualitative research, Content analysi

Fuzzy Logic Based Direct Power Control of Induction Motor Drive

This paper is the design of an induction motor drive system that can be controlled using direct power control. First the possibilities of direct power control (DPC) of induction motors (IMs) fed by a voltage source inverter have been studied. Principles of this method have been separately evaluated. Also the drive system is more versatile due to its small size and low cost. Therefore it is advantageous to use the system where the speed is estimated by means of a control algorithm instead of measuring. This paper proposed one novel induction motor speed control system with fuzzy logic. The estimator was designed and simulated in Matlab/Simulink. Simulation result shows a good performance of speed estimator

The Impact of Plasma Treatment of Cercon® Zirconia Ceramics on Adhesion to Resin Composite Cements and Surface Properties

Background: In recent years, the use of Ceramic base zirconia is considered because of chemical stability, biocompatibility, good compressive and flexural strength in dentistry for all ceramic restorations. However, due to its chemical stability, there is a challenge with dental bonding. Several studies have done to improving zirconia bonding but they are not reliable. Purpose of this research is a study of effect of plasma on bonding strength Zirconia.  Methods: In this research zirconia blocks' surfaces polished with 1200grit sandpaper. Samples were processed with plasma of oxygen, argon, air and oxygen-argon combination with 90-10 and 80-20 ratio.  Surface modifications were evaluated by contact angle, surface roughness, and topographical assessments. Cylindrical Panavia f2 resin-cement and Diafill were used for micro shear strength bond measurements. The data analysis was performed by SPSS 20.0 software and one-way analysis of variance. Results: The results showed that plasma can increase micro cutting bond strength, decrease surface roughness, increase surface activation energy. Maximum cutting bond strength by using Panavia f2 cement, is for air and argon plasma, and by using margin bond and Diafill composition cement, is for air and combination of oxygen and argon with 20-80 ratio.  Conclusion: According to this research plasmatic processing with dielectric barrier method in atmospheric pressure can increase Zirconia bonding strength

A study of the correlation between ventilator associated pneumonia and mortality rate of traumatic in patients in intensive care units

Background: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection among the traumatic in-patients in Intensive Care Units (ICUs). Trauma is a risk factor for the incidence of VAP, yet, the association between VAP and outcome is not clear in traumatic in-patients in ICUs. This study investigated the correlation between ventilator-associated pneumonia and mortality rate of traumatic in-patients in ICUs in Be'that Hospital in Hamedan, western Iran.Methods: This observational prospective study was conducted in the ICU of Be'that Hospital, Hamedan, Iran, during 1 year (March 2013 until February 2014). The population under study included traumatic in-patients aged less than 18 year who were in need of invasive mechanical ventilation for more than 48 h with APACHE SCORE II of less than 25. They were studied for the incidence or lack of incidence of VAP.Results: Of 154 patients under study, 114 cases (74%) suffered from multiple traumata, 32 cases (20.8%) were affected with head trauma, 5 cases (3.2%) sustained spinal cord injury, and 3 cases (1.9%) suffered from thoracic trauma. Also, 47 cases (30.5%) were affected with VAP. Compared to the non-VAP group, the patients in VAP group had longer ICU stay (18.5±6.21 days vs. 9.21±2.91 days, P<0.001), longer intubation time (13.7±4.7 days vs. 6.06±2.05 days, P<0.001), longer mechanical ventilation time (12.9±5.1 days vs. 5.7±1.9 days, P<0.001), and more repeated intubations (1.2±0.50 vs. 1±0.0, P<0.001). There was no statistically significant difference between the two groups with respect to APACHE SCORE II (14.8±2.3 vs. 14.9±2.9). Additionally, there was no significant difference between the two groups regarding mortality rate (10.6 vs. 5.6, P=0.215).Conclusions: VAP caused longer ICU stay, increased intubation time, increased mechanical ventilation time, and more repeated intubations in traumatic in-patients, yet, it did not increase mortality rate in these patients. Patients with spinal cord and thoracic traumata are at risk for affliction with VAP.

Experimental Investigation of Interfacial Tension Measurement and Oil Recovery by Carbonated Water Injection : A Case Study Using Core Samples from an Iranian Carbonate Oil Reservoir

The authors would like to gratefully acknowledge and appreciate the Department of Petroleum Engineering, Faculty of Engineering, Marvdasht Islamic Azad University, Marvdasht, 73711-13119, Iran, for the provision of the laboratory facilities necessary for completing this work.Peer reviewedPostprin