Mohammad Rahimi - Academia.edu (original) (raw)

Papers by Mohammad Rahimi

Journal of Teaching Language Skills, 2012

Following innovations in intelligence and its radical changes from a unitary concept (IQ) to a mu... more Following innovations in intelligence and its radical changes from a unitary concept (IQ) to a multi-dimensional conceptualization, i.e. multiple intelligences and the need to design classroom activities based on the L2 learners’ cognitive styles, this study examined the impact of linguistic intelligence and emotional intelligence on the reading comprehension ability of the Iranian EFL learners. Data was gathered through two questionnaires and a reading test and analyzed through two-way ANOVA and Multiple Regression. The results revealed that the students with a high level of linguistic intelligence showed a higher reading ability than those with a lower level of linguistic intelligence. The results, however, showed no significant difference among the students with different degrees of emotional intelligence. Moreover, the results indicated that linguistic intelligence is a relatively strong predictor of reading performance, accounting for more than 40% of the variance observed in t...

Journal of Teaching Language Skills, 2013

Investigating the discursive construction of EFL learners’ motivation is a relatively new area of... more Investigating the discursive construction of EFL learners’ motivation is a relatively new area of inquiry. Hence, there is a dearth of research into how foreign language learners’ discourse mediates their motivation construction. This study attempted to examine the discursive construction of two (one male and one female) Iranian EFL learners’ motivation in Shiraz University, Iran by examining their interpersonal relationships in the university where they attend, their future self-guides, and their personal struggles in, and alignment with social norms and requirements.. Employing Fairclough’s (2003) critical discourse analysis framework, the study revealed that EFL learners’ motivation is not single-dimensional and static; rather, it is complex, multi-dimensional and dynamic which is discursively constructed in the constant interaction between the individual and the social context. Findings also indicated that the discursive construction of EFL motivation involves the simultaneous i...

IEEE MTT-S International Microwave Symposium Digest, 2005.

Embedded networked sensing systems have been successfully applied to environmental monitoring in ... more Embedded networked sensing systems have been successfully applied to environmental monitoring in a wide range of applications. These first results have demonstrated a potential for advancing fundamental environmental science methods and environmental management capability as well as for providing future methods for safeguarding public health. While substantial progress in sensor network performance has appeared, new challenges have also emerged. Specifically, the inevitable and unpredictable time evolution of environmental phenomena introduces sensing uncertainty and degrades the performance of event detection, environment characterization, and sensor fusion. Many of the physical obstacles encountered by static sensors may be circumvented by a new method, Networked Infomechanical Systems (NIMS). NIMS integrates distributed, embedded sensing and computing systems with infrastructure-supported mobility to enable direct uncertainty characterization, autonomous adjustment of spatiotemporal sampling rate, and active sensor fusion. NIMS actuation is also being applied to advancing sensor network performance through methods based on control of distributed, directional antenna systems. In addition to advances in fundamental research objectives, this presentation will describe the architecture, implementation, and application of NIMS now deployed and continuously operating in the field... Index Terms-Wireless networked sensors, mobile wireless networking.

Proceedings of the National Academy of Sciences of the United States of America, Jan 12, 2015

Blue phases of liquid crystals represent unique ordered states of matter in which arrays of defec... more Blue phases of liquid crystals represent unique ordered states of matter in which arrays of defects are organized into striking patterns. Most studies of blue phases to date have focused on bulk properties. In this work, we present a systematic study of blue phases confined into spherical droplets. It is found that, in addition to the so-called blue phases I and II, several new morphologies arise under confinement, with a complexity that increases with the chirality of the medium and with a nature that can be altered by surface anchoring. Through a combination of simulations and experiments, it is also found that one can control the wavelength at which blue-phase droplets absorb light by manipulating either their size or the strength of the anchoring, thereby providing a liquid-state analog of nanoparticles, where dimensions are used to control absorbance or emission. The results presented in this work also suggest that there are conditions where confinement increases the range of s...

50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012

For hypersonic propulsion conditions of interest, several mechanism reduction strategies have bee... more For hypersonic propulsion conditions of interest, several mechanism reduction strategies have been developed by taking advantage of broad range of chemical time scales under high temperature conditions. The reduction methodologies include application of (i) principal component analysis based on sensitivity of ignition, flame propagation, extinction limits and partially-stirred reactor simulations to extract skeletal reaction models, (ii) quasisteady state approximation to obtain reduced reaction models, and (iii) rate-controlled constraint-equilibrium dimension reduction method to represent the chemistry using a reduced set of represented species. In addition, implementation of the in-situ adaptive tabulation approach to partially-stirred reactor simulations has been demonstrated for a set of selected mixing conditions relevant for turbulent reacting flows. In this paper, the above model reduction approaches have been applied to a newly optimized ethylene-air detailed kinetic model.

Proceedings of the 3rd international conference on Embedded networked sensor systems - SenSys '05, 2005

Recent technological progress in integrated low power CMOS based imaging devices has led to new t... more Recent technological progress in integrated low power CMOS based imaging devices has led to new type of sensors such as Cyclops. Cyclops is a CMOS image sensor, with reduced complexity and power that allows it to mate with typical sensor network nodes such as Motes. This motivates a new class of sensor networks which exploit vision. In this demonstration we introduce a network of Motes that carry Cyclops sensors. In this network, each individual node can be programmed to perform specific operation on the image. These operations include detecting objects in the scene, detecting edges, reporting histogram of the image, getting the image across the network or getting only particular region of interest. The demonstration showcases the functionality of our network to detect objects. Each node in the network is programmed to detect presence of the objects in its field of view. In addition, users can request the whole image or particular region of interest which the presence of the object has been detected. Performance studies as well as architectural choices will be presented along with outstanding challenges and opportunities.

Proceedings of the 2nd international conference on Embedded networked sensor systems - SenSys '04, 2004

Monitoring of environmental phenomena with embedded networked sensing confronts the challenges of... more Monitoring of environmental phenomena with embedded networked sensing confronts the challenges of both unpredictable variability in the spatial distribution of phenomena, coupled with demands for a high spatial sampling rate in three dimensions. For example, low distortion mapping of critical solar radiation properties in forest environments may require two-dimensional spatial sampling rates of greater than 10 samples/m 2 over transects exceeding 1000 m 2. Clearly, adequate sampling coverage of such a transect requires an impractically large number of sensing nodes. This paper describes a new approach where the deployment of a combination of autonomous-articulated and static sensor nodes enables sufficient spatiotemporal sampling density over large transects to meet a general set of environmental mapping demands. To achieve this we have developed an embedded networked sensor architecture that merges sensing and articulation with adaptive algorithms that are responsive to both variability in environmental phenomena discovered by the mobile sensors and to discrete events discovered by static sensors. We begin by describing the class of important driving applications, the statistical foundations for this new approach, and task allocation. We then describe our experimental implementation of adaptive, event aware, exploration algorithms, which exploit our wireless, articulated sensors operating with deterministic motion over large areas. Results of experimental Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.

Biophysical Journal, 2015

and cholesterol content have a profound effect on the sequestration of integrins in raft-mimickin... more and cholesterol content have a profound effect on the sequestration of integrins in raft-mimicking lipid mixtures. 1,2 These experimental findings can be explained on the basis of hydrophobic matching arguments and domain-specific lipid packing conditions. The described model membrane approach is also applied to investigate the oligomerization and sequestration behavior of GPIanchored urokinase plasminogen activator receptor (uPAR). Here native ligands, but not cholesterol content, were found to impact dimerization level and sequestration of uPAR in raft-mimicking lipid mixtures. 3 Corresponding experiments on mixtures of integrins and uPAR also illustrate the formation of integrin-uPAR complexes with distinct sequestration properties. Notably, these findings support a mechanism, in which GPI-anchored proteins cause the translocation of transmembrane proteins to lipid rafts.

PICMET '09 - 2009 Portland International Conference on Management of Engineering & Technology, 2009

Abstract--As Gregory Bateson, the British social scientists, once said You can't live witho... more Abstract--As Gregory Bateson, the British social scientists, once said You can't live without an eraser, the process of learning is not a unidirectional way toward accumulation of knowledge, rather, organizations should critically evaluate the value of their knowledge ...

2010 IEEE International Conference on Wireless Communications, Networking and Information Security, 2010

Abstract Sampling is one of the most common and repeated tasks in a target tracking sensor networ... more Abstract Sampling is one of the most common and repeated tasks in a target tracking sensor network. However, tuning the sampling rate parameter can be a challenging issue considering all the sensor network restrictions. In this paper, we propose two adaptive ...

2009 14th International CSI Computer Conference, 2009

Abstract This paper, proposes the use of a reinforcement learning approach for a target tracking ... more Abstract This paper, proposes the use of a reinforcement learning approach for a target tracking sensor network application. Harsh and unpredictable situations of sensor nodes in such an application requires a self-tuning mechanism for the nodes to adapt their ...

English Language Teaching, 2011

The current study examined differential effects of two pre-modification types, syntactic elaborat... more The current study examined differential effects of two pre-modification types, syntactic elaboration and syntactic simplification (at the level of syntax and irrespective of problematic lexis), on EST students’ reading comprehension. The purpose was to see whether a priori syntactic elaborative adjustment, given its advantages over simplification, can augment comprehensibility of scientific texts in order to replace simplification adjustment. To carry out the study, three versions of 5 passages including Baseline, syntactically simplified, and syntactically elaborated were provided. All the five passages were relevant to civil engineering and they were modified using two above-mentioned techniques. The subjects of the study were composed of 185 homogenous civil engineering students who participated in different phases. The results revealed that syntactic simplification and syntactic elaboration procedures operated nearly in the same way in orienting the EST texts toward comprehensib...

SSRN Electronic Journal, 2011

The causal relationship between government revenue and government expenditure is an important sub... more The causal relationship between government revenue and government expenditure is an important subject in public economics especially to the control of budget deficit. The purpose of this study is to investigate the relationship between government revenue and government expenditure in Iran by applying the bounds testing approach to cointegration. The results of the causality test show that there is a bidirectional causal relationship between government expenditure and revenues in both long run and short run. Therefore, the results of this paper are consistent with fiscal synchronization hypothesis. The policy implication of results suggests that because of existing interdependence relation between government expenditure and revenue, the government makes its expenditures and revenues decision simultaneously. Under this hypothesis, the fiscal authorities of Iran should try to increase revenues and decrease expenditure simultaneously to control the budget deficits.

The Journal of Physical Chemistry C, 2013

ABSTRACT Performing coarse-grained molecular dynamics simulations, the local dynamics of free and... more ABSTRACT Performing coarse-grained molecular dynamics simulations, the local dynamics of free and grafted polystyrene chains surrounding a spherical silica nanoparticle has been investigated, where the silica nanoparticle was either bare or grafted with 80-monomer polystyrene chains. The effect of the free (matrix) chain molecular weight and grafting density on the relaxation time of both the free and grafted polystyrene chains has been investigated. Furthermore, we have analyzed the local mobility of the grafted chains at different separations from the nanoparticle surface, as well as on the mean square displacement of the nanoparticles. Proximity to the surface, confinement by the surface, increased grafting density and increased matrix chain length were found to slow down the dynamics of the chain monomers and hence to increase the corresponding relaxation times. “Drying” of the grafted network of the nanoparticle via increasing the free chain lengths, which is known to shrink the brush-height, was found to slow down the relaxation of the brushes, too. The thickness of the interphase, beyond which the polymers showed bulklike behavior, was 2 nm for a bare nanoparticle, corresponding to four monomer layers, for all matrix chain lengths investigated. It increased to 3 nm for grafted nanoparticles depending on the grafting density and the matrix chain molecular weight.

Reading and Writing, 2008

... to language pedagogy emphasize the importance of exclusive focus on communication andpragmati... more ... to language pedagogy emphasize the importance of exclusive focus on communication andpragmatic meaning and ... taught by the researcher during the spring of 2006 at Shiraz University,Iran. ... the improvement of the students&amp;#x27; listening skill had taken an Oxford Placement Test. ...

Pure and Applied Geophysics, 2011

ABSTRACT In order to study the temporal and spatial variation of fog days in Iran, the data of 11... more ABSTRACT In order to study the temporal and spatial variation of fog days in Iran, the data of 115 synoptic meteorological stations have been analyzed for years 1960–2005. The results revealed that different types of fogs form all over the country, apart from central areas of Iran that are located in the big dessert of Iran. Advection fogs are common in the south coast (Persian Gulf) and north coastal (Caspian Sea) regions. Upslope fogs form in the mountainous areas of the northwest and north parts of Iran. This study shows no height dependence relationship on fog days for all types of fogs in overall. The trend analysis of fog days during the last 20years shows some significant negative and positive trends. The frequency of advection fogs shows positive trends and most upslope fogs show negative trends. The results show that there are suitable places for fog collection projects in the north and south coastal regions during the year, especially in cold months. KeywordsFog–Fog days–Fog collection–Persian Gulf–Iran

Physical Review E, 2012

Biological membranes are continuously brought out of equilibrium, as they shape organelles, packa... more Biological membranes are continuously brought out of equilibrium, as they shape organelles, package and transport cargo, or respond to external actions. Even the dynamics of plain lipid membranes in experimental model systems are very complex due to the tight interplay between the bilayer architecture, the shape dynamics, and the rearrangement of the lipid molecules. We formulate and numerically implement a continuum model of the shape dynamics and lipid hydrodynamics, which describes the bilayer by its midsurface and by a lipid density field for each monolayer. The viscoelastic response of bilayers is determined by the stretching and curvature elasticity, and by the inter-monolayer friction and the membrane interfacial shear viscosity. While the bilayer equilibria are well understood theoretically, dynamical calculations have relied on simplified continuum approaches of uncertain transferability, or on molecular simulations reaching very limited length and time scales. Our approach incorporates the main physics, is fully nonlinear, does not assume predefined shapes, and can access a wide range of time and length scales. We validate it with the well understood tether extension. We investigate the tubular lipid transport between cells, the dynamics of bud absorption by a planar membrane, and the fate of a localized lipid density asymmetry in vesicles. These axisymmetric examples bear biological relevance and highlight the diversity of dynamical regimes that bilayers can experience.

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Mathematics and Computers in Simulation, 2010

Mistuning, imperfections in cyclical symmetry of bladed disks is an inevitable and perilous occur... more Mistuning, imperfections in cyclical symmetry of bladed disks is an inevitable and perilous occurrence due to many factors including manufacturing tolerances and in-service wear and tear. It can cause some unpredictable phenomena such as mode splitting, mode localization and dramatic difference in forced vibration response. In this paper first, a method is presented which calculates the forced vibration response of a mistuned system based on an exact relationship between tuned and mistuned systems. Then, the genetic algorithm is used for solving an optimization problem to find the worst-case response of bladed-disk assembly. The second part tries to find methods to reduce the system worst-case response. Intentional mistuning which breaks the nominal symmetry of a tuned bladed disk and rearranging the bladed-disk assembly are introduced and used to reduce the system worst-case response. Finally, a two degree of freedom per blade simplified model with 56 blades is used to demonstrate the capabilities of the techniques in reducing the worst response of the bladed-disk system.