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Search Results: 1 - 10 of 3454 matches for " Hamid Khosravi "
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Optimal Node Scheduling for Desired Percentage of Coverage in Wireless Sensor Networks  [PDF]
Hamid Khosravi
Wireless Sensor Network (WSN) , 2012, DOI: 10.4236/wsn.2012.45018
Abstract: Recent developments in wireless communication and embedded computing technologies have led to the advent of wireless sensor network technology. Hundreds of thousands of these micro sensors can be deployed in many areas including health, environment and battlefield in order to monitor the domain with desired level of accuracy. When wireless sensors are deployed in an area, the lifetime of the network should last as long as possible according to the original amount of energy. Therefore, reducing energy consumption in WSNs is of primary concern. We have proposed a node scheduling solution that solves the coverage and connectivity problem in sensor networks in an integrated manner. In this way we will divide network life time to finite number of rounds and in each round we will generate a coverage bitmap of sensors of the domain and based on this bitmap it will decided which sensors remain active or go to sleep. We will check the connection of the sensor network by using Laplacian of adjancy graph of active nodes in each round. Also the network will be capable of producing desired percentage of coverage by using coverage bitmap. We will define the connected coverage problem as an optimization problem and we will seek a solution for the problem by using Genetic Algorithm optimization method.
Massive cosmological scalar perturbations
Nima Khosravi,Hamid Reza Sepangi,Shahab Shahidi
Physics , 2012, DOI: 10.1103/PhysRevD.86.043517
Abstract: We study the cosmological perturbations of the new bi-metric gravity proposed by Hassan and Rosen \cite{hasan} as a representation of massive gravity. The mass term in the model, in addition of ensuring ghost freedom for both metrics, causes the two scale factors to mix at the cosmological level and this affects the cosmological perturbation of the model. We find two combinations corresponding to the entropy and adiabatic perturbations of the theory. In this sense we show that the adiabatic perturbations could be a source for the entropy perturbations. So in addition to the adiabatic perturbations, entropy perturbations can also be present in this theory. We also show that the adiabatic perturbations are not constant at the super horizon scales, implying that the theory could not be used to describe the inflationary epoch, even if it can impose some corrections to the standard inflationary scenarios.
A comparison of direct measurement of low density lipoprotein cholesterol level in serum with standard Friedewald, De-Long and modified Friedewald equation
Ahmad Khosravi,Majid Noorian,Hosein Khosravi-Broojeni,Hamid Kalalian-Moghaddam
Knowledge & Health Journal , 2007,
Abstract: Introduction: Reduction of low density lipoprotein cholesterol (LDL-C) in persons with coronary heart disease (CHD) is targeted. First step in treatment of lowering the LDL-C level is lifestyle modification including diet, weight reduction and exercise. At second step, the lipid lowering drug should be added. Although direct measurement of LDL-C from serum is most accurate, but it is not cost-effective, so laboratories usually use the Friedewald equation that suffers from several limitations such as hypertriglyceridemia and variability of lipoprotein composition. The authors compared and determined the correlation of LDL-C from enzymatic measurement with LDL-C from calculating.Methods and Materials: A total of 475 fasting serum samples (199 males and 276 females with mean age of 56.3 years) with TG less than 400 mg/ dl in Imam Hossein hospital (Shahroud) were analyzed. According to serum TG levels, samples divided in four groups (<100, 100-199, 200-299, 300-400). Authors calculated the LDL-C and then compared with direct measurement. Data analyzed with SPSS and table curve packages. Results: The comparison between direct and calculated methods showed that: 1) Concordance with the difference of 0±20 mg/dl is low. 2) Friedewald showed more accuracy compared with other calculated methods (51.2% versus 38.7% and 42.7%). 3) with the raising of TG, the accuracy declines and the overestimation increases. Correlation coefficient was 0.66.Conclusion: An overestimation of approximately 0±20 mg/dl was found in over 50% of samples comparison with direct LDL-C. Therefore; direct measurement of LDL-C in patients with CHD is recommented.
The Antibiotic Resistance Profiles of Bacterial Strains Isolated from Patients with Hospital-Acquired Bloodstream and Urinary Tract Infections
Hamed Ghadiri,Hamid Vaez,Samira Khosravi,Ebrahim Soleymani
Critical Care Research and Practice , 2012, DOI: 10.1155/2012/890797
An empirical study on evaluating training program: A case study of university employee
Hamid Reza Rezazadeh Bahadoran,Aliakbar Khosravi Babadadi,Sara Tountab Haghighi
Management Science Letters , 2011,
Abstract: In this paper, we present an empirical study on measuring the effects of training programs on efficiency of university employee. The proposed model of this paper uses Kirkpatrick four level models based on some questionnaire. The questions are divided into four different groups of reflection, leaning, behavior and efficiency and the feedback are collected using Likert scales. We perform some statistical tests to analyze the results and conclude that staff training has relatively positive impact on all four items. In addition, the effects of different personal characteristics such as age, gender and marriage conditions are investigated on all four levels of Kirkpatrick's model. The results indicate that the Kirkpatrick could be implemented for measuring the effects of training programs, efficiently.
Relapse of Acute Myeloid Leukemia as Isolated Bilateral Testicular Granulocytic Sarcoma in an Adult
Mojtaba Ghadiany,Hamid Attarian,Abbas Hajifathali,Adnan Khosravi
Urology Journal , 2008,
The Antibiotic Resistance Profiles of Bacterial Strains Isolated from Patients with Hospital-Acquired Bloodstream and Urinary Tract Infections
Hamed Ghadiri,Hamid Vaez,Samira Khosravi,Ebrahim Soleymani
Critical Care Research and Practice , 2012, DOI: 10.1155/2012/890797
Abstract: Treatment of nosocomial infections is becoming difficult due to the increasing trend of antibiotics resistance. Current knowledge on antibiotic resistance pattern is essential for appropriate therapy. We aimed to evaluate antibiotic resistance profiles in nosocomial bloodstream and urinary tract pathogens. A total of 129 blood stream and 300 urinary tract positive samples were obtained from patients referring to Besat hospital over a two-year period (2009 and 2010). Antibiotic sensitivity was ascertained using the Kirby-Bauer disk diffusion technique according to CLSI guidelines. Patient's data such as gender and age were recorded. The ratio of gram-negative to gram-positive bacteria in BSIs was 1.6?:?1. The most prevalent BSI pathogen was Coagulase-Negative Staphylococci (CoNS). The highest resistance rate of CoNS was against penicillin (91.1%) followed by ampicillin (75.6%), and the lowest rate was against vancomycin (4.4%). Escherichia coli was the most prevalent pathogen isolated from urinary tract infections (UTIs). Ratio of gram-negative to gram-positive bacteria was 3.2?:?1. The highest resistance rate of E. coli isolates was against nalidixic acid (57.7%). The present study showed that CoNS and E. coli are the most common causative agents of nosocomial BSIs and UTIs, and control of infection needs to be addressed in both antibiotic prescription and general hygiene. 1. Introduction Nosocomial or hospital-acquired infections are defined as infections which are acquired during the hospital stay. Nosocomial infections are usually defined as infections that are identified at least 48–72 hours following admission to health institutions [1]. Nosocomial infections are also important public health problems in developing countries as well as in developed countries [2]. The most frequent types of nosocomial infections are urinary tract infection (UTI), surgical-wound infection, pneumonia, and bloodstream infection (BSI) [3]. BSIs are responsible for approximately 10–30% of the cases [4]. UTI is the presence of bacteria in the urine (bacteriuria) and defined as the growth of a single pathogen of >105 colony-forming units/mL from properly collected mid-stream urine specimens [5]. The common bacterial pathogens present in the BSIs and UTIs are Staphylococcus aureus, Coagulase-Negative Staphylococci (CoNS), Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter spp., Enterococcus spp., and Acinetobacter spp. [6]. As the result of extensive uses of antimicrobial agents, nosocomial pathogens have shifted away from easily treatable bacteria
Multi-Metric Gravity via Massive Gravity
Nima Khosravi,Nafiseh Rahmanpour,Hamid Reza Sepangi,Shahab Shahidi
Physics , 2011, DOI: 10.1103/PhysRevD.85.024049
Abstract: A generalization to the theory of massive gravity is presented which includes three dynamical metrics. It is shown that at the linear level, the theory predicts a massless spin-2 field which is decoupled from the other two gravitons which are massive and interacting. In this regime the matter naturally should be coupled to massless graviton which introduces a preferred metric that is the average of the primary metrics. The cosmological solution of the theory shows the de-Sitter behavior with a function of mass as its cosmological constant. Surprisingly, it lacks any non-trivial solution when one of the metrics is taken to be Minkowskian and seems to enhance the predictions which suggests that there is no homogeneous, isotropic and flat solution for the standard massive cosmology.
Design of 1.33 μm and 1.55 μm Wavelengths Quantum Cascade Photodetector  [PDF]
S. Khosravi, A. Rostami
Optics and Photonics Journal (OPJ) , 2017, DOI: 10.4236/opj.2017.78B016
In this paper, a quantum cascade photodetector based on intersubband transitions in quantum wells with ability of detecting 1.33 μm and 1.55 μm wavelengths in two individual current paths is introduced. Multi quantum wells structures based on III-Nitride materials due to their large band gaps are used. In order to calculate the photodetector parameters, wave functions and energy levels are obtained by solving 1-D Schrodinger–Poisson equation self consistently at 80 ?K. Responsivity values are about 22 mA/W and 18.75 mA/W for detecting of 1.33 μm and 1.55 μm wavelengths, respectively. Detectivity values are calculated as 1.17 × 107 (Jones) and 2.41 × 107 (Jones) at wavelengths of 1.33 μm and 1.55 μm wavelengths, respectively.
Antioxidant Activity of Essential Oil of Lallemantia iberica in Flowering Stage and Post-Flowering Stage
Yaghoub Amanzadeh,Nafiseh Khosravi Dehaghi,Ahmad Reza Gohari,Hamid Reza Monsef-Esfehani,Seyed Esmail Sadat Ebrahimi
Research Journal of Biological Sciences , 2012, DOI: 10.3923/rjbsci.2011.114.117
Abstract: In this study, the essential oils from the arial parts of Lallemantia iberica (Lamiaceae), collected in 2 stages (flowering and post-flowering) from plants that caltivated in Institute of Medicinal Plants (ACECR) in Hashtgerd of Iran were obtained by hydrodistillation in Clevenger type apparatus. The chemical components of the essential oils were examined by GC and GC-MS then 36 components were characterized in flowering stage with β-cubeben (19.55%), Linalool (18.71%), spathulenol (18.04%), β-caryophyllene (11.11%), geraniol (3.50%) and bicyclogermacrene (3.46%) as the major constituents. All constituents are representing 97.39% of the essential oil, contained monoterpenes (33.85%) and sesquiterpens (63.54%). About 39 components of essential oil of post-flowering stage were introduced which caryophylene oxide (38.77%), linalool (15.15%), Germacrene-D (7.03%), Trans-caryophylene (5.61%), β-bourbonene (4.96%) and Trans-geraniol (4.34%) as the major constituents of it. All components are representing 95.74% of the essential oil contained monoterpens (26.51%) and sesquiterpens (69.23%). The studied essential oils showed antioxidant activities as calculated by 2 in vitro assays; DPPH radical scavenging and Ferric Reducing Power Assay (FRAP).
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