Showing 7 results for Zamanian
Volume 5, Issue 2 (6-2016)
Abstract
Cicada orni Linnaeus, 1758 is an abundant and common cicada across Europe, North Africa, and western Asia including Iran. The male cicada produces a loud calling song for attraction of females from a long distance. The calling songs are known often to be species-specific and to function in part for species recognition. The present study compares variations in calling song of C. orni in Iran with those reported from other areas and also signifies the importance of calling song in species identification. C. orni were collected in Mazandaran, Iran during summer 2010. Four features were used: echeme duration, echeme period, interecheme interval, number of echeme/s and dominant frequency. Findings of present study showed some resemblance in time and frequency domains in the calling song among the populations of C. orni from Iran and those investigated in Greece, Iberian Peninsula and Turkey. The parameters of calling song showed maximal resemblance with species of Kosmas (Greece). The present results do not support C. orni from Iran as an independent subspecies. Thus, it is concluded that every feature of calling song can be effective in species recognition as is the case for several other parameters.
R. Moradzadeh, J. Nazari, A. Orouji, M. Zamanian, M. Shamsi, N. Chezani-Sharahi,
Volume 10, Issue 2 (Spring 2022)
Abstract
Aims: Health literacy has gained increasing attention in public health. It was aimed to assess health literacy and the related determinants among mothers with children under 6 years old.
Instrument & Method: In this population-based cross-sectional study, 1483 mothers were included through stratified random sampling. The study included demographic variables and socioeconomic status based on asset variables. Data was collected through Health Literacy for Iranian Adults questionnaire. The analysis was conducted in SPSS 16.0 and STATA 12.0 software using the principal component and adjusted linear regression models
Findings: The mean age of the children was 2.1±1.5. The mean score of health literacy was 70.2±17.5 in mothers. There was a significant association between the mother’s and her husband’s permanent jobs and socioeconomic status and total health literacy (p<0.05). Minimum and maximum scores of health literacy were obtained in the appraisal and understanding subscales, respectively. Totally, 36.4% of the participants had adequate health literacy.
Conclusion: The health literacy of the mothers was relatively high.
Volume 15, Issue 5 (7-2015)
Abstract
In this study, the static deflection and natural frequency of an electrostatically excited patch-coated microcantilever beam are analyzed. The proposed model is considered as the main element of many microsensors and microswitches. Firstly, the nonlinear motion equation is extracted by means of Hamilton principle, assuming shortening effect. Secondly, differential equations, governing the static deflection and free vibration equation around the stability point, are solved using Galerkin method and the three mode shapes of a uniform microbeam are employed as the comparison function. By assuming that the volume of deposited layer is constant, the variation of natural frequency and static deflection are examined in three different cases. In any cases, it is presumed that the second layer is initially deposited on the entire length of microbeam. In the first case, one end of coated layer is considered fix at the clamped side of microcantilever, and then its length is decreased from other side, where its thickness is increased. In the second case, one end of coated layer is perceived fix at the free side of microcantilever, and then its length is decreased from other side, where its thickness is escalated. In the third case, the length of second layer is decreased from both of left and right ends, where its thickness is expanded. In addition, the effect due to the change of the second layer position is considered on mechanical behavior of the system.
Volume 17, Issue 12 (2-2018)
Abstract
One of the main topics in the field of robotics is the motion control of wheeled mobile robots. Motion control encompasses trajectory tracking and point stabilization problems. In this paper these control problems will be considered for the tractor-trailer wheeled robots and a predictive control algorithm is developed for solving these problems. Therefore first kinematic model of the tractor_trailer robot is developed. Next, reference trajectories is produced for the system. Subsequently, predictive control law is designed for the trajectory tracking and point stabilization problems. Predictive control based on the known values of reference trajectories in the future, produces the control inputs in present time. Consequently the error signal with respect to the reference trajectory in future will be used in order to control the system at the present instant of time. This method is developed for solving the aforementioned control problems and is employed on the tractor_trailer wheeled robot. As can be seen from the results, the proposed control algorithm steer the wheeled robot asymptotically follow reference trajectories. Obtained results from the implementation of the proposed method for solving trajectory tracking and point stabilization problems, demonstrate the effectiveness of the presented algorithm.
Volume 18, Issue 5 (9-2018)
Abstract
In this study, control design of a T shaped mass connected to the clamped-clamped microbeam excited by electrostatic actuation is investigated. The actuation force is generated by applying an electric voltage between the horizontal part of T shaped mass and an opposite electrode plate. In this model, the micro-beam is modeled by Euler-Bernoulli theory as a continuous beam. The T-shaped assembly connected to the the microbeam is assumed as a rigid body and nonlinear effect of electrostatic force is considered. Equations of motion and associated boundary condition are derived using the Lagrange’s principle. The differential equation of nonlinear vibration around the static position is discretized using Galerkin method.. The discretized equations are solved by the perturbation theory. To improve the dynamics behavior of systems, nonlinear control feedback has been presented. The controller regulates the pass band of microcantilever and analytically approximate the nonlinear resonance frequency and amplitudes of the periodic solutions when the microcantilever is subjected to one point and fully distributed feedback forces. The results of paper may be used for improving the design of mass sensors based on nonlinear jump phenomena.
Volume 24, Issue 4 (10-2024)
Abstract
Piers are vital design elements for a bridge under seismic loading; ensuring their stability and health is crucial for the overall safety of the bridge. The most common methods available for detecting damage, primarily used in the bridge deck, are modal methods. These methods have errors in detecting damage in the structure for various reasons. On the other hand, these methods require healthy pier information. In addition to modal methods, other methods based on energy and data analysis using wavelet transform also exist, the shortcomings of which are mentioned in this article. The fundamental problem that most methods face is the existence of healthy pier information, and furthermore, parameters that should be used to detect damage must be computable or measurable. In this study, a new method is presented, using the concept of correlation, to detect the presence and location of damage with minimal error and without having healthy pier information. To this end, the tallest pier of Ramp A of the Shahid Bakri Bridge complex in Tehran was selected as the case study. Before modeling, the accuracy of the modeling method was validated, and then a precise nonlinear model was built in the OpenSees software using as-built sheets. For the first time in this article, damage in the model was created in different scenarios: reduction of stiffness in concrete cover materials, reduction of cross-sectional area of rebars at various points of the section. The location of the damage was also separately applied at three heights of the pier: 15, 25, and 35 percent of the height. To generate data on the pier, it was considered to load it with an impact load on the top of the pier. This load was applied as an impact on the deck of the pier for a very short time, and the data was collected using accelerometers at the pier height, and the correlation between each pair of consecutive sensors was calculated. Due to the high velocity of the compressive wave in concrete and the overlap that occurs in the return of the wave at both ends of the pier, data collection was performed only for about 0.001 seconds. Finally, due to the weakness of the correlation coefficient in magnifying the location of damage, using the concept of correlation, a damage index based on this concept was presented, and the capability of the presented index in detecting the presence and location of damage in various damage scenarios was evaluated. The results obtained indicate the proper performance of this index in detecting damage in various scenarios and damage intensities between 10 and 30 percent. The presented index only made an error in detecting the location of damage in cases where damage occurred in the concrete cover and rebars in small areas, but even in these cases, the presence of damage was well demonstrated. Due to limitations in sensor placement at the pier height, increasing the distance between sensors and reducing their number was also investigated, and it was observed that even with greater distances between sensors, the presented index has the capability to detect the presence and location of damage, and after finding the approximate location of damage, it is possible to identify the exact location of damage by re-sensoring in probable areas.
Volume 24, Issue 4 (Winter 2024)
Abstract
Aim and Introduction
Today, with the expansion of globalization and increased economic competition, capital accumulation has been proposed as one of the main factors of the economic growth process of the countries, which can be provided through domestic or foreign sources. Meanwhile, inadequacy of internal resources and the need for high technical knowledge in some countries that seek economic growth have required a serious approach to this issue. Furthermore, countries with limited domestic resources are not able to expand exports and acquire shares from new markets, and they need stable resources to provide capital and their needs, among which attracting foreign capital is one of the economic solutions. Indirect foreign investment includes investments made by foreign natural and legal entities in the form of buying securities of a financial institution and company and providing them to the host country during a process. Due to the important role of foreign direct investment, the global market for attracting these funds has become really competitive. Such competition has been formed especially among developing countries due lack of financial resources on the one hand, and the need for achieving rapid development on the other. Therefore, it is crucilaly important to identify the factors affecting the flow of foreign direct investment. As a result, the aim of the present study is to investigate the relationship between foreign investment and crimes committed in 31 provinces of the country during 2001-2021 using panel data regression models and unit root stationarity tests of Levin, Lin and Chu, Im, Pesaran and Shin, Fisher and Fisher.
Methodology
According to the theoretical foundations of foreign direct investment and crime and the study conducted by Daniele and Marani in 2008, regression model (panel data) and static test have been considered to investigate the relationship between foreign direct investment and crime. In other words, in the estimation of regression models in the form of time series, it is critically important to check the stationarity of the variables, and for this purpose, Levin, Lin and Chu, Im, Pesaran and Shin, Fisher and Fisher tests were used in this study. The variables investigated in this study include foreign direct investment as a dependent variable and population variables, GDP per capita, industry index, degree of openness of the regional economy, infrastructure index and crime variable as an independent variable.
Findings
The results indicate that the test of the first model shows a negative relationship between foreign direct investment and crime, which is not statistically significant. In other words, with the increase in crime, the power to attract foreign direct investment in each province decreases. The results of the second model indicate that the logarithm of GDP per capita has a negative and significant effect on the entry of foreign direct investment. In other words, with the increase of GDP in each province, the amount of foreign direct investment attraction decreases. In the third model, in addition to the gross domestic product, the logarithm of the investment of exploitation licenses issued in each province as an industry index of each province has been entered into the model, which has a negative and significant effect on foreign direct investment. In the fourth model, the variable related to the country's infrastructure, which in this study is the amount of electricity subscribers of each province, has a positive and significant effect, and by entering the infrastructure variable, the effect of other variables is the same as before. The variable of the degree of openness of the economy in the fifth model shows a positive and significant effect on foreign direct investment, and it shows that the more suitable the country has for trade with other countries, the more the desire to invest in the country increases and the more foreign direct investment is attracted. GDP per capita variables and industry index have a negative and significant effect, and the infrastructure variable also has a positive and significant effect on foreign direct investment. In final model where the population variable is entered, the results indicate a negative and significant effect of the population on foreign direct investment. In other words, with the increase in population, the power to attract direct investment in each province decreases.
Discussion and Conclusion
The results obtained from the present study indicate that although, based on the data examined in this study, crimes have not had a significant effect on the attraction of foreign direct investment, but the negative effects of GDP per capita and the industry index indicate that despite Iran's capabilities, it requires official and long-term planning to provide the necessary ground for attracting foreign direct investments. It seems that a step can be taken in this direction by applying the reduction of restrictions in the field of commercial policies, especially the foundation through tariff and customs policies and application of protective laws and regulations