Papers by Amirreza Keshtkar
This paper reports on a study that investigated the effect of teaching test-taking strategies on ... more This paper reports on a study that investigated the effect of teaching test-taking strategies on Iranian high school students' performance on English section of the National University Entrance Examination (Konkoor). To do so, 273 male and female high school students participated in a workshop that lasted for four sessions. The participants were randomly divided into an experimental and a control group. In the beginning of the workshop, participants received a demographic questionnaire to see if they had taken part in a similar test-taking class which resulted in excluding some students from the groups. The groups were also homogenized regarding their language proficiency level by administering Oxford Placement Test (OPT). Therefore, 260 participants were left for the main study. Then, experimental group participated in the test-taking strategy workshop and control group worked on the previous samples of Konkoor examinations without any reference to test-taking strategies. At th...
Background and Aims: Electric pulp testing is used for diagnosis of the pulp status. This test is... more Background and Aims: Electric pulp testing is used for diagnosis of the pulp status. This test is technique sensitive and hence may elicit positive or negative false response in case of inaccurate use. The optimal site for placement of the probe tip has not been determined. The aim of this study was to evaluate the effect of pulp tester probe placement site on the response of maxillary teeth. Materials and Methods: A total of 378 teeth (126 central incisors, 126 lateral incisors and 126 canines) in 67 voluntary 20-35 year-old patients were selected. Three sites on each tooth (incisal edge, labial and lingual surfaces) were tested with an electrical pulp tester and responses were recorded. Data were analyzed by Repeated Measure ANOVA test. Results: The central incisor teeth showed significantly lower sensation threshold than lateral incisor and canine teeth (P<0.001). The incisal edge of tooth were significantly more sensitive compared to labial and lingual surfaces (P=0.008). Con...
Effects of corm size and plant density on Saffron (Crocus sativus L.) yield and its components
In this paper we show that, it’s possible the uniform motion on the arbitrary trajectory and numb... more In this paper we show that, it’s possible the uniform motion on the arbitrary trajectory and number of examples that can be cited for uniform motion is infinite. As an application of this method, we can conclude uniform circular motion as an especial state. Also as another application, we investigate Archimedean spiral so that particle moves by constant speed on this path. We believe, this procedure illustrates the application of simple mathematical tools to physics, a barrier that some student have difficulty to overcome.
Critical Thinking and Critical Reading: Issues and Implications
Critical thinking is an important and vital topic in modern education; but much evidence suggests... more Critical thinking is an important and vital topic in modern education; but much evidence suggests that students ’ thinking skills are not adequate to meet the challenges that they face. Many educational reports have argued that the education systems fail to teach many students how to think effectively. All educators are interested in teaching critical thinking to their students. Many academic departments expect their professors and instructors to be well informed about the strategy of teaching critical thinking skills identify areas in one’s courses as the proper place to emphasize and teach critical thinking and develop and use some problems in exams that test students ’ critical thinking skills. On the other hand, Reading critically precedes thinking critically. Readers discover information and ideas when they analyze and reflect on the ideas they read. The topic of teaching students to think while reading – critical reading – should be central to any discussion of thinking skills...
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1.1 What is BNN Toolbox?........................ 2
In this paper, application of self-organizing spiking neural networks to mobile robot path planni... more In this paper, application of self-organizing spiking neural networks to mobile robot path planning problem is presented. A network of spike-response-model neurons with a recurrent architecture is used to create robot’s internal representation from surrounding environment. The overall activity of network simulates a self-organizing system with unsupervised learning. A modified A * algorithm is used to find the best path using this internal representation between start and goal points. The results show good performance even for complex obstacles configurations. 1
Beyond interoperability to digital ecosystems: regional innovation and socio-economic development... more Beyond interoperability to digital ecosystems: regional innovation and socio-economic development led by SMEs Article (Accepted version)
Given the strong link between reading comprehension and vocabulary learning, this classroom-based... more Given the strong link between reading comprehension and vocabulary learning, this classroom-based study was designed to examine 1) the effect of assisted reading on vocabulary learning of Iranian EFL learners,
This paper reports the effect of Sn doping on structural and optical properties of CuO nanopartic... more This paper reports the effect of Sn doping on structural and optical properties of CuO nanoparticles prepared by the simple hydrothermal method in mild condition without pH adjustment and surfactant. The structural and optical properties of these CuO and Sn doped CuO particles were investigated using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectroscopy (PL). powder X-ray analysis reveals that Sn +4 ion have substituted the Cu +2 ions without changing the monoclinic structure of CuO but the average particle size of nano CuO increases from 16 nm to 22 nm.The PL emission spectra revealed blue shift after introducing Sn into the CuO and an intensity decreasing as well.
Background: The presence of an infected family member significantly increases the risk of HBV tra... more Background: The presence of an infected family member significantly increases the risk of HBV transmission, but many socio-demographic and viral characteristics of family members affect the transmission rate. Objectives: In this study, we have used data mining techniques to investigate the impact of different variables in intrafamilial transmission of HBV infection. Patients and Methods: demographic information, viral markers, and medical history of 330 patients with chronic hepatitis B and their offspring attending a referral center in Tehran were collected. Data-mining techniques were administered to detect patterns. Results: The overall transmission rate was 15.7% (5.4% and 27.3% for male and female index cases respectively). In female patients, HBe Ag positively affected the transmission rate (49% vs. 23.4%). There was a dominant change in transmission rate of female patients with negative results for Hbe Ag with HDV coinfection, where the transmission rate changed from 25% in patients with negative results for HDV Ab to 5% in those with positive results. In Hbe Ag negative male index cases, the transmission rate was 1.3% in cases with positive results for HDV Ab compared to 7% in those with negative findings. The overall transmission rate was statistically different between patients with positive and negative results for HDV Ab (P = 0.016). Conclusions: There is a minor but consistent pattern change in the presence of HDV infection which reduces familial transmission of HBV, especially in female patients with negative results for HBe Ag.
Support vector machines for classification have the advantage that the curse of dimension-ality i... more Support vector machines for classification have the advantage that the curse of dimension-ality is circumvented. It has been shown that a reduction of the dimension of the input space leads to even better results. For this purpose, we propose two information criteria which can be computed directly from the definition of the support vector machine. We assess the predictive performance of the models selected by our new criteria and compare them to existing variable selection techniques in a simulation study. The simulation results show that the new criteria are competitive in terms of generalization error rate while being much easier to compute. We arrive at the same findings for comparison on some real-world benchmark datasets.
The production and application of PET tracers has been a unique step in the progress of nuclear m... more The production and application of PET tracers has been a unique step in the progress of nuclear medicine in last two decades. The most important PET tracers include F-18, C-11 and N-13 radioisotopes and many nuclear medicine centers throughout the globe are using them. However some new tracers are under their way to the mass administration, currently being in the clinical trials or preliminary studies. Gallium-66 and 68 tracers such as Ga-DOTANOC and Ga-DOTANIC are currently being used in many neuroendocrine tumor studies in human in Europe and North America, and global application of these tracers remain to the cheaper and easier providence of 68Ge/68Ga generators. Copper tracers such as 61,62,64Cu-ATSM and 61,62,64Cu-PTSM are the most important unconventional tracers used in hypoxia and perfusion studies respectively using PET technology. Copper tracers can easily be produced using a medium cyclotron with simple chemistry. Many other interesting PET radioisotopes such as Tc-94m (H...
� A promising biologically inspired model for object recognition. � Simple features. � Good perfo... more � A promising biologically inspired model for object recognition. � Simple features. � Good performance with low number of training samples. � Operates well on different object categories without extensive tunings. � Universal dictionary of features. Our Motivations � Recurrent (feedback/lateral) connections. � Sparse representation. � Overcomplete representation. � Online unsupervised learning.
� How visual cortex (V1) represents images? � Visual cortex as an hierarchical inference machine.
— In this paper, a model of self-organizing spiking neural networks is introduced and applied to ... more — In this paper, a model of self-organizing spiking neural networks is introduced and applied to mobile robot environment representation and path planning problem. A network of spike-response-model neurons with a recurrent architecture is used to create robot’s internal representation from surrounding environment. The overall activity of network simulates a self-organizing system with unsupervised learning. A modified A * algorithm is used to find the best path using this internal representation between starting and goal points. This method can be used with good performance for both known and unknown environments.
Computers have been used in education for more than three decades. Computer-based training (CBT) ... more Computers have been used in education for more than three decades. Computer-based training (CBT) and computer-aided instruction (CAI) were the first such systems deployed as an attempt to teach using computers. Computer-based training has two important branches 1) E-Learning System and 2) Intelligent Tutoring Systems. Both systems have strengths and weaknesses. It is well known that e learning Systems not provide the same kind of individualised attention that a student would receive from a human tutor, as they do not reason about the domain and the learner. This has prompted research in the field of intelligent tutoring systems (ITSs). ITSs achieve their intelligence by representing pedagogical decisions about how to teach as well as information about the learner. They have been shown to be highly effective at increasing students' performance and motivation The goals of learning no longer were solely based on acquiring skills and facts but started to include the strategies and p...
Amir Reza Zekavat (2019): Application of X-ray Computed Tomography for Assessment of Additively M... more Amir Reza Zekavat (2019): Application of X-ray Computed Tomography for Assessment of Additively Manufactured Products. Örebro studies in Technology 85.
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Papers by Amirreza Keshtkar