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      • SCOPUSKCI등재

        Gender Differences in Clinical Presentations of Cystic Fibrosis Patients in Azeri Turkish Population

        Vahedi, Leila,Jabarpoor-Bonyadi, Morteza,Ghojazadeh, Morteza,Vahedi, Amir,Rafeey, Mandana The Korean Academy of Tuberculosis and Respiratory 2016 Tuberculosis and Respiratory Diseases Vol.79 No.4

        Background: Cystic fibrosis (CF) is an autosomal recessive disorder with several clinical presentations. This study was undertaken in the Azeri Turkish population in Iran, to investigate gender differences in the age at onset and diagnosis, age of death, and duration of illness of CF. Methods: The data of 331 CF patients from 2001 to 2015 was surveyed. Parameters including age, sex, ${\Delta}F508$ mutation, age at onset, age at diagnosis, age of death and clinical presentations were evaluated for both sexes, using descriptive analysis. The association of gender with these variables was studied using logistic regression, chi-square test and Mann-Whitney U test by SPSS version 18. Odds ratio with a confidence interval of 95% and $p{\leq}0.05$ was considered statistically significant. Results: The study included 191 males (57.7%) and 140 females (42.3%), all showing statistically significant difference (p<0.001). Age duration differed between genders. Male and female patients were further under 9 and 4 years, respectively. The occurrence of ${\Delta}F508$ mutation was 0.51 times more in females than in males. Age, diagnosis and sex were closely associated: males were diagnosed at a significantly later age than females (p=0.05). While this compression performed based on clinical presentations, males with respiratory disease had a later median age at diagnosis than females at lifespan (p=0.001). The risk of infertility in males was approximately two times greater than in females (p=0.02). Conclusion: These findings indicate gender differences in CF patients. Future studies are needed to establish other differences and evaluate the causes for the gender variations.

      • KCI등재

        Gender Differences in Clinical Presentations of Cystic Fibrosis Patients in Azeri Turkish Population

        ( Leila Vahedi ),( Morteza Jabarpoor-bonyadi ),( Morteza Ghojazadeh ),( Amir Vahedi ),( Mandana Rafeey ) 대한결핵 및 호흡기학회 2016 Tuberculosis and Respiratory Diseases Vol.79 No.4

        Background: Cystic fibrosis (CF) is an autosomal recessive disorder with several clinical presentations. This study was undertaken in the Azeri Turkish population in Iran, to investigate gender differences in the age at onset and diagnosis, age of death, and duration of illness of CF. Methods: The data of 331 CF patients from 2001 to 2015 was surveyed. Parameters including age, sex, △F508 mutation, age at onset, age at diagnosis, age of death and clinical presentations were evaluated for both sexes, using descriptive analysis. The association of gender with these variables was studied using logistic regression, chi-square test and Mann- Whitney U test by SPSS version 18. Odds ratio with a confidence interval of 95% and p≤0.05 was considered statistically significant. Results: The study included 191 males (57.7%) and 140 females (42.3%), all showing statistically significant difference (p<0.001). Age duration differed between genders. Male and female patients were further under 9 and 4 years, respectively. The occurrence of △F508 mutation was 0.51 times more in females than in males. Age, diagnosis and sex were closely associated: males were diagnosed at a significantly later age than females (p=0.05). While this compression performed based on clinical presentations, males with respiratory disease had a later median age at diagnosis than females at lifespan (p=0.001). The risk of infertility in males was approximately two times greater than in females (p=0.02). Conclusion: These findings indicate gender differences in CF patients. Future studies are needed to establish other differences and evaluate the causes for the gender variations.

      • SCOPUSKCI등재

        Edentulous child with Allgrove syndrome: a rare case report

        Vahedi, Mohammad,Fathi, Shima,Allahbakhshi, Hanif The Korean Pediatric Society 2016 Clinical and Experimental Pediatrics (CEP) Vol.59 No.11

        Triple-A syndrome, also known as Allgrove syndrome, is a rare autosomal recessive disorder. The 3 features of this syndrome are achalasia, adrenal insufficiency, and alacrima. Achalasia could be the first manifestation of the triple-A syndrome; however, its etiology is unclear. Alacrima is generally asymptomatic but can be detected by obtaining patient history. Although adrenal insufficiency could have manifestations such as asthenia, it might be wrongly diagnosed as muscle fatigue. Vitamin D and calcium supplements are usually prescribed for the prevention of osteoporosis. Neurologic manifestations could be present in adults. In some individuals with this disorder, genetic examination indicates mutations in both alleles of the AAAS gene, which encodes a special 546-amino-acid protein designated ALADIN, and in chromosome 12q13. The genetic cause of the triple A syndrome in some patients who do not have an identified mutation is unknown. While very few such cases have been reported till date, one such case was presented to us as an edentulous child.

      • SCIESCOPUSKCI등재

        Weighting Method to Identify Interharmonics based on Calculating the Bandwidth in Group-Harmonics

        Vahedi, Hani,Kiapi, Alireza Alizadeh,Bina, Mohammad Tavakoli,Al-Haddad, Kamal The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

        Power converters produce a vast range of harmonics, subharmonics and interharmonics. Harmonics analyzing tools based on the Fast Fourier Transform (FFT) assume that only harmonics are present and the periodicity intervals are fixed, while these periodicity intervals are variable and long in the presence of interharmonics. Using FFT may lead to invalid and undesired results due to the above mentioned issues. They can also lead to problems such as frequency blending, spectral leakage and the picket-fence effect. In this paper, the group-harmonic weighting (GHW) approach has been presented to identify the interharmonics in a power system. Afterwards, a modified GHW has been introduced to calculate the proper bandwidth for analyzing the various values of interharmonics. Modifying this method leads to more precise results in the FFT of a waveform containing inter harmonics especially in power systems with a fundamental frequency drift or frequency interference. Numerical simulations have been performed to prove the efficiency of the presented algorithm in interharmonics detection and to increase the accuracy of the FFT and the GWH methods.

      • SCIESCOPUS

        Structural reliability assessment using an enhanced adaptive Kriging method

        Vahedi, Jafar,Ghasemi, Mohammad Reza,Miri, Mahmoud Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.6

        Reliability assessment of complex structures using simulation methods is time-consuming. Thus, surrogate models are usually employed to reduce computational cost. AK-MCS is a surrogate-based Active learning method combining Kriging and Monte-Carlo Simulation for structural reliability analysis. This paper proposes three modifications of the AK-MCS method to reduce the number of calls to the performance function. The first modification is related to the definition of an initial Design of Experiments (DoE). In the original AK-MCS method, an initial DoE is created by a random selection of samples among the Monte Carlo population. Therefore, samples in the failure region have fewer chances to be selected, because a small number of samples are usually located in the failure region compared to the safe region. The proposed method in this paper is based on a uniform selection of samples in the predefined domain, so more samples may be selected from the failure region. Another important parameter in the AK-MCS method is the size of the initial DoE. The algorithm may not predict the exact limit state surface with an insufficient number of initial samples. Thus, the second modification of the AK-MCS method is proposed to overcome this problem. The third modification is relevant to the type of regression trend in the AK-MCS method. The original AK-MCS method uses an ordinary Kriging model, so the regression part of Kriging model is an unknown constant value. In this paper, the effect of regression trend in the AK-MCS method is investigated for a benchmark problem, and it is shown that the appropriate choice of regression type could reduce the number of calls to the performance function. A stepwise approach is also presented to select a suitable trend of the Kriging model. The numerical results show the effectiveness of the proposed modifications.

      • Zero-Temperature Study of a Tetrameric Spin-1/2 Chain in a Transverse Magnetic Field

        Vahedi, J.,Arbousara, M. S.,Mahdavifar, S. Springer Science + Business Media 2017 Journal of low temperature physics Vol.186 No.3

        <P>We consider an alternating Heisenberg spin-1/2 antiferromagnetic-ferromagnetic chain with the space-modulated dominant antiferromagnetic exchange and anisotropic ferromagnetic coupling (tetrameric spin-1/2 chain). The zero-temperature effect of a symmetry breaking transverse magnetic field on the model is studied numerically. It is found that the anisotropy effect on the ferromagnetic coupling induces two new gapped phases. We identified their orderings as a kind of the stripe antiferromagnetic phase. As a result, the magnetic phase diagram of the tetrameric chain shows five gapped quantum phases, and the system is characterized by four critical fields which mark quantum phase transitions in the ground state of the system with the changing transverse magnetic field. We have also exploited the well-known bipartite entanglement (name as concurrence) and global entanglement tools to verify the occurrence of quantum phase transitions and the corresponding critical points.</P>

      • SCISCIESCOPUS

        Spin and charge thermopower effects in the ferromagnetic graphene junction

        Vahedi, Javad,Barimani, Fattaneh American Institute of Physics 2016 Journal of Applied Physics Vol.120 No.8

        <P>Using wave function matching approach and employing the Landauer-Buttiker formula, a ferromagnetic graphene junction with temperature gradient across the system is studied. We calculate the thermally induced charge and spin current as well as the thermoelectric voltage (Seebeck effect) in the linear and nonlinear regimes. Our calculation revealed that due to the electron-hole symmetry, the charge Seebeck coefficient is, for an undoped magnetic graphene, an odd function of chemical potential while the spin Seebeck coefficient is an even function regardless of the temperature gradient and junction length. We have also found with an accurate tuning external parameter, namely, the exchange filed and gate voltage, the temperature gradient across the junction drives a pure spin current without accompanying the charge current. Another important characteristic of thermoelectric transport, thermally induced current in the nonlinear regime, is examined. It would be our main finding that with increasing thermal gradient applied to the junction the spin and charge thermovoltages decrease and even become zero for non zero temperature bias. Published by AIP Publishing.</P>

      • KCI등재

        Weighting Method to Identify Interharmonics based on Calculating the Bandwidth in Group-Harmonics

        Hani Vahedi,Alireza Alizadeh Kiapi,Mohammad Tavakoli Bina,Kamal Al-Haddad 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

        Power converters produce a vast range of harmonics, subharmonics and interharmonics. Harmonics analyzing tools based on the Fast Fourier Transform (FFT) assume that only harmonics are present and the periodicity intervals are fixed, while these periodicity intervals are variable and long in the presence of interharmonics. Using FFT may lead to invalid and undesired results due to the above mentioned issues. They can also lead to problems such as frequency blending, spectral leakage and the picket-fence effect. In this paper, the group-harmonic weighting (GHW) approach has been presented to identify the interharmonics in a power system. Afterwards, a modified GHW has been introduced to calculate the proper bandwidth for analyzing the various values of interharmonics. Modifying this method leads to more precise results in the FFT of a waveform containing inter harmonics especially in power systems with a fundamental frequency drift or frequency interference. Numerical simulations have been performed to prove the efficiency of the presented algorithm in interharmonics detection and to increase the accuracy of the FFT and the GWH methods.

      • KCI등재

        Sensitivity Analysis of Tubular-Web Reduced Beam Section Connections Under Cyclic Loading

        Masood Vahedi,Reza Ardestani,Seyed Mehdi Zahrai 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.1

        Recently a new type of Reduced Beam Section (RBS) connection called “Tubular Web RBS (TW-RBS)” has been numerically and experimentally studied. TW-RBS connections are made by replacing a part of web with a tube or pipe at the desirable location of the beam plastic hinge. This paper aims to numerically investigate the eff ect of key factors such as position, diameter, and thickness of the tube on the hysteretic behavior of the connection under cyclic load using ABAQUS fi nite element software. First, a model is used for verifi cation purposes where good correlation with experimental results was achieved. Then, 14 models are defi ned by varying the key parameters and subjected to cyclic loading. The eff ects of such factors on the behavior of the connection are investigated in order to fi nd out consequences of probable defects during the implementation of TW-RBS connections or intentional utilizing of other pipes in TW-RBSs. Based on the results, the position of the tube is the most sensitive factor in the behavior of TW-RBS connections and its improper location leads to unreliable design, probable plastic hinge formations in unpredicted regions, and possible failure in the connection zone. On the contrary, diameter and thickness of the tube have negligible eff ect on the energy dissipation mainly depending on beam section properties.

      • KCI등재

        Structural reliability assessment using an enhanced adaptive Kriging method

        Jafar Vahedi,Mohammad Reza Ghasemi,Mahmoud Miri 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.6

        Reliability assessment of complex structures using simulation methods is time-consuming. Thus, surrogate models are usually employed to reduce computational cost. AK-MCS is a surrogate-based Active learning method combining Kriging and Monte-Carlo Simulation for structural reliability analysis. This paper proposes three modifications of the AK-MCS method to reduce the number of calls to the performance function. The first modification is related to the definition of an initial Design of Experiments (DoE). In the original AK-MCS method, an initial DoE is created by a random selection of samples among the Monte Carlo population. Therefore, samples in the failure region have fewer chances to be selected, because a small number of samples are usually located in the failure region compared to the safe region. The proposed method in this paper is based on a uniform selection of samples in the predefined domain, so more samples may be selected from the failure region. Another important parameter in the AK-MCS method is the size of the initial DoE. The algorithm may not predict the exact limit state surface with an insufficient number of initial samples. Thus, the second modification of the AK-MCS method is proposed to overcome this problem. The third modification is relevant to the type of regression trend in the AK-MCS method. The original AK-MCS method uses an ordinary Kriging model, so the regression part of Kriging model is an unknown constant value. In this paper, the effect of regression trend in the AK-MCS method is investigated for a benchmark problem, and it is shown that the appropriate choice of regression type could reduce the number of calls to the performance function. A stepwise approach is also presented to select a suitable trend of the Kriging model. The numerical results show the effectiveness of the proposed modifications.

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