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Search Results: 1 - 10 of 239 matches for " Bahman Nagipour "
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Adjustment of Preoperative Fasting Guidelines for Adult Patients Undergoing Elective Surgery  [PDF]
Eissa Bilehjani, Solmaz Fakhari, Samira Yavari, Jafar Rahimi Panahi, Mohammadreza Afhami, Bahman Nagipour, Hojjat Pourfathi, Haleh Farzin, Ladan Javidi
Open Journal of Internal Medicine (OJIM) , 2015, DOI: 10.4236/ojim.2015.54016
Abstract: Introduction: The typical order of nothing per oral (NPO) after midnight has been challenged in recent years, thus the American Society of Anesthesiology (ASA) revised in practice guidelines for preoperative fasting in healthy patients undergoing elective procedures, but many studies have showed that guidelines were not considered in clinical practice. The aim of this study was to evaluate the adjustment of preoperative NPO time with fasting guidelines in adult elective ophthalmic surgeries in a university educational ophthalmology hospital in Tabriz, Iran. Methods: In 3 months period, this descriptive study was conducted on 250 patients who scheduled for elective eye surgery. The investigator interviewed with patients before beginning of anesthesia and evaluated fasting duration for heavy meal, light meal and clear liquids and his or her satisfaction from NPO time and also investigated which staff recommended NPO time before anesthesia induction. Results: Fasting duration from heavy and light meal and clear liquids was 14.31 hours (8 - 23 hours), 12.46 hours (6 - 21 hours) and 11.54 hours (3 - 18 hours), respectively, that was not consistent with ASA guidelines. The discontent of the patients from prolonged NPO time was 60.8%. The most complaint was thirsty (42%). Ward nurses were the personnel who had the primary role in patients fasting time period (47.6%). Conclusion: Preoperative fasting duration for heavy and light meal and clear liquids for elective ophthalmic surgery in this teaching hospital was very long and not consistent with ASA guidelines. Ward nurses had the major role in this malpractice. Thus it seems that personnel education may be very helpful.
On the Performance of Blind Chip Rate Estimation in Multi-Rate CDMA Transmissions Using Multi-Rate Sampling in Slow Flat Fading Channels  [PDF]
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.12011
Abstract: This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response is estimated by a subspace method, and then the chip rate of each signal is estimated using zero crossing of estimated differential channel impulse response. For chip rate estimation of each user, an algorithm which uses weighted zero-crossing ratio is proposed. Maximum value of the weighted zero crossing ratio takes place in the Nyquist rate sampling frequency, which equals to the twice of the chip rate. Furthermore, bit time of each user is estimated using fluctuations of autocorrelation estimators. Since code length of each user can be obtained using bit time and chip time ratio. Fading channels reduce reliability factor of the proposed algo-rithm. To overcome this problem, a receiver with multiple antennas is proposed, and the reliability factor of the proposed algorithm is analyzed over both spatially correlated and independent fading channels.
Investigation of Crystallization and Microstructure of Na2O-CaO-P2O5-SiO2-Al2O3 Bio Glass Ceramic System  [PDF]
Bahman Mirhadia, Behzad Mehdikhanib
New Journal of Glass and Ceramics (NJGC) , 2012, DOI: 10.4236/njgc.2012.21001
Abstract: The effects of Al2O3 on the crystallization behavior of glass compositions in the Na2O-CaO-P2O5-SiO2 system were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In this system, thermal parameters of glasses were studied by DTA. The density of the glass ceramic samples was measured by Archimedes’ method. It was found that the glass-ceramic containing 2.0 molar percent Al2O3 had desirable sintering behavior and reached to an acceptable density. Phase investigation and micro structural study were performed by XRD and SEM, respectively.
A Novel Cooperative Spectrum Sharing Algorithm Based on Optimal Cognitive Radio User Selection  [PDF]
Mohammad Bigdeli, Bahman Abolhassani
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.51002
Abstract: In this paper, we consider the problem of cognitive radio (CR) user selection to maximize overall CR network (CRN) throughput when the available spectrum bandwidth is less than the demand by all CR users. We formulate optimal CR user selection problem. Then, based on approximation of the average received signal to interference plus noise ratio (SINR) and adaptive modulation and coding (AMC), we estimate the required bandwidth of CR users with different required quality of services (QoSs). Using the principle of optimality, we propose a novel cooperative spectrum sharing algorithm for a CRN. The proposed algorithm not only achieves exhaustive search performance but also its complexity is in the order of N × M versus 2N for exhaustive search, where N is the number of CR users, and M is the spectrum pool size. Extensive simulation results illustrate that the proposed algorithm significantly outperforms the existing algorithms that ignore optimal CR user selection. Also, these results illustrate a better fairness criterion than those of previous works.
The Neural Network That Can Find the Maximum Income of Refinery  [PDF]
Bahman Mashood, Greg Milbank
Open Journal of Optimization (OJOp) , 2014, DOI: 10.4236/ojop.2014.32002
In this article we are going to introduce the neural network approach to approximate the solution for optimization problems. Using this approach we are able to approximate the optimum values for the large class of functions in particular giving the prices of different products that are resulted from refining the crude petroleum into different substances. We are going to design a neural network that can provide us with a decomposition of the given crude petroleum into resulted products in such a way that is most beneficial for the refinery.
The Role of Assertiveness and Self-Assertion in Female High School Students’ Emotional Self-Regulation  [PDF]
Bahman Allahyari, Hossein Jenaabadi
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.614163
Abstract: The current study aimed to investigate the role of assertiveness and self-assertion in emotional self-regulation of female students. The statistical population included all second period female high school students in Jalagh, in the academic year 2014-2015, among which 200 students were selected using census method. This was a descriptive-correlational study. To collect data, Assertion Inventory (Gambrill & Richie, 1975) and Cognitive-Emotion Regulation Questionnaire (Garnefski et al., 2001) were used. To analyze the obtained data, both descriptive (mean, standard deviation) and inferential statistics (Pearson correlation coefficient and regression analysis) were applied, using SPSS. The results indicated that all subscales of emotional self-regulation were significantly related to assertiveness and self-assertion.
Evaluation of Ecology, Land Uses in Different Parts and the State of the Land Uses’ per Capita of Ahwaz City  [PDF]
Bahman Bahadori, Vladimir Boynagryan
Open Journal of Ecology (OJE) , 2016, DOI: 10.4236/oje.2016.66029
Abstract: There has been a progressively rivalry among different cities for attaining development opportunities and attraction of economic and social capitals in the recent years. In this universal rivalry, the quality of spaces and urban design are considered as key factors for evaluating cities. Therefore, in this research in order to comprehend the spatial deficiency of the public welfare services in different regions of Ahwaz city, issues such as land uses in different parts of the city, the state and per capita of land uses in the city and comparison of the current land uses with per capita of Comprehensive Plan approved in 1988 are analyzed. Also, evaluation and comparison of the land uses distribution state in different parts of Ahwaz in form of different regions of the city, population distribution in those regions, residential spaces distribution in the regions, commercial spaces distribution in the regions, educational spaces distribution in the regions, religious, sanitary and therapeutic, athletic, administrative spaces, green spaces and other spaces distribution in the different regions are also evaluated in this research.
Advances in Theory of Neural Network and Its Application  [PDF]
Bahman Mashood, Greg Millbank
Journal of Behavioral and Brain Science (JBBS) , 2016, DOI: 10.4236/jbbs.2016.65022
Abstract: In this article we introduce a large class of optimization problems that can be approximated by neural networks. Furthermore for some large category of optimization problems the action of the corresponding neural network will be reduced to linear or quadratic programming, therefore the global optimum could be obtained immediately.
A Study on the Conversion of a Semigroup to a Semilattice  [PDF]
Bahman Tabatabaie, Seyed Mostafa Zebarjad
Advances in Pure Mathematics (APM) , 2011, DOI: 10.4236/apm.2011.13016
Abstract: The main aim of the current research has been concentrated to clarify the condition for converting the inverse semigroups such as S to a semilattice. For this purpose a property the so-called has been de-fined and it has been tried to prove that each inverse semigroups limited with show the specification of a semilattice.
A Two Step Secure Spectrum Sensing Algorithm Using Fuzzy Logic for Cognitive Radio Networks  [PDF]
Ehsan Moeen Taghavi, Bahman Abolhassani
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2011, DOI: 10.4236/ijcns.2011.48062
Abstract: In this paper, a two step secure spectrum sensing algorithm is proposed for cognitive radio networks. In this algorithm, the sensing results of secondary users are pre-filtered and applying fuzzy logic, so, the overall sensing performance of the network is improved. To determine pre-filter parameters, statistical parameters of the sensing results are used to remove those sensing results which are far from the majority sensing results. However, to obtain a better performance in the spectrum sensing, we propose a fuzzy logic to nullify the effects of malicious users who transmit false sensing data to the fusion center. We further propose a Fuzzy Trust Level for each user as to weight the sensing result of the corresponding user before combining all sensing results in the fusion center. Simulation results demonstrate that our proposed algorithm yield significant improvement in the performance of the spectrum sensing and identifying malicious users.
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