In wireless communications which are widely applicable nowadays, the channel variation over time and frequency is a major problem. Therefore, the channel estimation and compensation are critical challenges in these systems. The OFDM technique is noteworthy for wireless channels due to robustness, high efficiency and consequently high data rate. Pilot-aided channel estimation is a promising approach in many OFDM systems, including mobile networks, digital audio and video broadcasting standards. The number and the arrangement of pilots in the time-frequency grid affect the accuracy and the period of the channel estimation procedure. Practical OFDM systems utilize fixed pilot patterns that are designed based on typical assumptions of the fading channel. Thus, unnecessary pilot overhead is imposed when the channel is close to a flat slow fading channel, and the performance degrades in the worst condition of the channel. To remedy this issue, adaptive pilot arrangement based on the channel response is introduced in the previous researches. Indeed, finding the best pilot arrangement according to the channel response is an optimization problem and the adaptive approach is exploited to find its answer. In this paper, we develop a novel method for adaptive pilot arrangement based on Kalman filter which is combined with the channel estimation algorithm. Therefore, the position of the pilots and the channel response are jointly estimated in the proposed method. This method is simulated for various channel types and its performance is evaluated by bit error rate (BER) and pilot overhead criteria. Simulation results illustrate that the proposed method obtains the same performance as the previous methods by fewer pilots. This achievement leads to significant increase in the capacity of data transfer.

In this research, for the first time, the net of control points in the isogeometric analysis has been improved by employing an error estimator based on a stress recovery method. First, an error estimation algorithm based on stress recovery is used to obtain the energy norm for each element. Then, artificial rods are defined between control points and the estimated values of errors in the control points located at the vicinity of a typical point is assigned to each rod as a thermal gradient. Now, by analyzing this hypothetical truss problem under temperature changes a new arrangement of control points and consequently the knot vectors can be obtained. Repeating this process in isogeometric analysis will lead to a better distribution of errors in the domain of the problem and results in an optimal net of control points to calculate the integrals. To evaluate the efficiency of this method, the results of modeling and analysis of two elasticity problem is presented. The obtained results show that this innovative approach has a good performance and can be employed for reducing the analysis errors.

This case study examined the ADAPTIVITY of learning transfer from an English for general academic purposes course to different disciplinary writing contexts. Data were collected at the end of one academic semester from 7 students of engineering disciplines enrolled in the writing course. Their EGAP writing course lasted for 16 weeks over which they were taught The St. Martin's Handbook, 6th Edition. The participants’,disciplinary writings together with interview transcripts served as the data sources for the extraction of adaptive transfers and also the processes of realizing the transfers. Adaptive transfers were identified by the participants. The findings indicated that learning outcomes can transfer adaptively through a variety of processes to accommodate the new writing demands. The results of the study showed that the participants could adapt their learning along two broad dimensions of transfer, ‘, idea generation’,(IG) and ‘, text construction’,(TC) with the former involving ‘, explication’,and ‘, integration’,of knowledge and the latter achieved at macro and micro levels. Within these adaptive transfers, we found a range of writing issues pursued including ‘, goals, topics, logics, propositions, integrity, disciplinarity, linearity, paragraphing, and linguistic resources’, . Furthermore, the findings displayed two broad categories of ‘, higher order’,and ‘, lower order’,processes employed for the realization of adaptive transfers. While higher-order processes operated through ‘, transformative and evaluative’,mechanisms, the lower-order processes involved two categories of ‘, avoidance and affordance’, , with the former as an attempt to refrain from going wrong and the latter as an effort to generate ADAPTIVITY. The findings for L2 writing are theoretically discussed.

In this research, the efficiency of error estimation based on two methods of recovering the equilibrium stress of patches and superconvergent points in guiding the adaptive solution of nonlinear problems by isogeometric method has been investigated. Also, by analyzing elasto-plastic problems based on material properties, and adaptive solution by temperature gradient method, the stress improvement process has been investigated. The method of the adaptive solution of this research is based on the movement of control points and it is used in stress recovery, taking into account the difference between the exact stress level and the stress level obtained from the isogeometric analysis for each element, as a criterion to determine the amount of error in it. The element is obtained. For this purpose, the modeling of two problems in the non-linear range, which has an exact solution, has been considered. The results have shown that the total norm difference of exact and approximate error in both stress recovery methods used is more than 33% and in the direction of improving the network of control points. Also, the method by equilibrium patches is more effective than the method based on superconvergent points, which can be used as a suitable solution to improve the stress field.

Numerical methods, especially the Finite Element method, are increasingly being used for solving different problems. Due to fact that these methods are approximate, having a good understanding and judgment about the errors and their distribution is very important.Hence education of users of engineering analysis and design software is necessary and inattention to it may result in catastrophe. As regards this issue, the problem of determining the stress intensity factor in a cracked plate under tensile stresses, by using the finite element method together with error estimation and ADAPTIVITY, is the subject of this article. For this purpose, an academic FORTRAN code has been developed which is able to estimate the finite element solution error by using the superconvergent patch stress recovery method. In addition, an adaptive solution with remeshings in each step is carried out to improve the quality of the employed finite element mesh. Comparing the obtained results with the analytical solution, as well as the ANSYS commercial software, it is observed that the employed algorithm for error estimation has a better performance and can be used for determination of the stress intensity factor in complex structures with arbitrary cracks.

The purpose of this study was to extract career adaptability profiles of students and predict their membership based on adaptability's indicators including career optimism, proactive personality and core self-evaluations. This study was a basic quantitative and a kind of correlational andantecedent one. A sample size of 700 students were selected through size proportional stratified sampling method. The Savickas and Porfeli's Career Adaptability Scale, Seibert, Crant and Kraimer's Proactive Personality Scale, Judge, Erez, Bono and Thoresen's Core Self-evaluation Scale and Rottinghaus, Day and Borgen's Career Optimism Scale were used to collect the data. Results showed that there is distinct quantitative adaptability profiles namely very low, low, average, and high. In addition, a distinct qualitative profile was extracted which was named disconfidence with high levels of concern, control and curiosity and a low level of confidence. Also, the results showed that distinct adaptability profiles differed significantly in their levels of ADAPTIVITY so that increasing the levels of ADAPTIVITY, in terms of its three indicators, predicts the likelihood of membership in higher levels of adaptability profiles. However, differently, in the disconfidence profile, increasing of the core self-evaluation predicts the likelihood of subscribing to the profile named high. Finally part of the model of adaptation was supported. Overall, the results showed that there are different adaptability profiles among students. Moreover, different levels of ADAPTIVITY in terms of career optimism, proactive personality and core self-evaluation, predict the individual's membership in different profiles.

Estimation of a quantile density function from biased data is a frequent problem in industrial life testing experiments and medical studies. The estimation of a quantile density function in the biased nonparametric regression model is inves-tigated. We propose and develop a new wavelet-based methodology for this problem. In particular, an adaptive hard thresholding wavelet estimator is constructed. Under mild assumptions on the model, we prove that it enjoys powerful mean integrated squared error properties over Besov balls. The performance of proposed estimator is investigated by a numerical study. In this study, we develop two types of wavelet estimators for the quantile density function when data comes from a biased distribution function. Our wavelet hard thresholding estimator which is introduced as a nonlinear estimator, has the feature to be adaptive according to q(x). We show that these estimators attain optimal and nearly optimal rates of convergence over a wide range of Besov function classes.

In this paper, a novel selective DC fault detector approach based on the adaptive cumulative sum method (ACUSUM) is suggested for the protection of high voltage direct current (HVDC) transmission lines. Using a communication channel, the proposed method detects DC fault occurrence as well as determining faulty line at a multi-terminal HVDC (MT-HVDC) transmission system; the whole in less than 2ms. The suggested approach works in the time domain and employs the ACUSUM method as a mathematical tool for detecting abrupt variation at the magnitude of lines current for fault detection. Simulation results confirm the selectivity of the proposed algorithm at different DC fault situations which enhances the reliability of the power system. Besides the low sampling rate, the ACUSUM calculation burden is very low and its implementation needs no special or complicated hardware. Rather than appropriate speed, ADAPTIVITY, independence from system parameters, robustness against fault resistance, fault distance and noise are significant advantages of the proposed algorithm in comparison with other methods. ADAPTIVITY, independency from system parameters, robustness against fault resistance, fault distance and noise are significant advantages of the proposed algorithm in comparison with other methods.