A Study of the Attitude of Tehranian Customers to Electronic Services in Tourism Industry

Yalda Erfani Fard,Alireza Dehghan 세계문화관광학회 2009 International Journal of Culture and tourism Resea Vol.2 No.1

Improving e-tourism is dependent on attitude to cyberspace in addition to hardware investment. The purpose of this paper is to examine the attitude of Tehranian passengers within the context of online travel Website functionality and content preferences as well as search behavior. The attitude of passengers to use electronic services of tourism is an important variant that is studied here. Our theoretical framework in this study is The Theory of Reasoned Action (Ajzen &Fishbein). It suggests that a person's behavior is determined by his/her intention to perform the behavior and that this intention is, in turn, a function of his/her attitude toward the behavior and his/her subjective norm. A test of this model, with data collected from 600 consumers by questionnaire indicates that using on-line services of tourism is strongly influenced by attitude toward on-line services of tourism, normative beliefs, and respondents' trust to cyberspace.

The beneficial effects of beam web opening in seismic behavior of steel moment frames

Saeed Erfani,Ata Babazadeh Naseri,Vahid Akrami 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.1

Implementation of openings in beams web has been introduced as an innovative method for improving seismic performance of steel moment frames. In this paper, several steel moment frames have been studied in order to evaluate the effect of openings in beams web. The beam sections with web opening have been modeled as a simplified super-element to be used in designing frames and to determine opening configurations. Finite element models of designed frames were generated and nonlinear static pushover analysis was conducted. The efficient location for openings along the beam length was discovered and the effects of beams with web openings on local and global behavioral characteristics of frames were discussed. Base on the results, seismic performance of steel moment frames was improved by creating openings in beams web, in terms of reduction in stress level of frame sensitive areas such as beam to column connections and panel zones.

Numerical investigation on the flexural links of eccentrically braced frames with web openings

S. Erfani,A. Vakili,V. Akrami 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.2

Plastic deformation of link beams in eccentrically braced frames is the primary dissipating source of seismic energy. Despite the excellent compatibility with the architectural designs, previous researches indicate the deficiency of flexural yielding links compared to the shear yielding ones because of their localized plastic deformation. Previous investigations have shown that implementing web openings in beams could be an efficient method to improve the seismic performance of moment-resisting connections. Accordingly, this research investigates the use of flexural links with stiffened and un-stiffened web openings to eliminate localized plasticity at the ends of the link. For this purpose, the numerical models are generated in finite element software “Abaqus” and verified against experimental data gathered from other studies. Models are subjected to cyclic displacement history to evaluate their behavior. Failure of the numerical models under cyclic loading is simulated using a micromechanical based damage model known as Cyclic Void Growth Model (CVGM). The elastic stiffness and the strength-based and CVGM-based inelastic rotation capacity of the links are compared to evaluate the studied models' seismic response. The results of this investigation indicate that some of the flexural links with edge stiffened web openings show increased inelastic rotation capacity compared to an un-perforated link.

An analytical model for shear links in eccentrically braced frames

Saeed Erfani,Amir Ashtari 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.3

When an eccentrically braced frame (EBF) is subjected to severe earthquakes, the links experience inelastic deformations while beams outside of the link, braces and columns are designed to remain elastic. To perform reliable inelastic analyses of EBFs sufficient analytical model which can accurately predict the inelastic performance of the links is needed. It is said in the literature that available analytical models for shear links generally predict very well the maximum shear forces and deformations from experiments on shear links, but may underestimate the intermediary values. In this study it is shown that available analytical models do not predict very well the maximum shear forces and deformations too. In this study an analytical model which can accurately predict both maximum and intermediary values of shear force and deformation is proposed. The model parameters are established based on test results from several experiments on shear links. Comparison of available test results with the hysteresis curves obtained using the proposed analytical model established the accuracy of the model. The proposed model is recommended to be used to perform inelastic analyses of EBFs.

A Nonlinear Macro-model for Numerical Simulation of Perforated Steel Beams

Saeed Erfani,Vahid Akrami 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.5

Perforated steel beams are being used widely in moment resisting frames. Given the computational expense of detailed numerical simulations, it seems necessary to introduce a simplifi ed macro-model to be used in nonlinear analyses. This paper presents a nonlinear macro-model for numerical simulation of perforated steel I-beams. Results of fi nite element analysis on eighty perforated beams are used to calibrate the parameters of proposed macro-model. Then, results from proposed macromodel are verifi ed against eight experiments gathered from other references and nine FE models analyzed by authors. The comparison shows that, the proposed macro-model has acceptable accuracy and can be utilized for further studies on the perforated steel I-beams.

Evaluation of cyclic fracture in perforated beams using micromechanical fatigue model

Saeed Erfani,Vahid Akrami 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.4

It is common practice to use Reduced Web Beam Sections (RWBS) in steel moment resisting frames. Perforation of beam web in these members may cause stress and strain concentration around the opening area and facilitate ductile fracture under cyclic loading. This paper presents a numerical study on the cyclic fracture of these structural components. The considered connections are configured as T-shaped assemblies with beams of elongated circular perforations. The failure of specimens under Ultra Low Cycle Fatigue (ULCF) condition is simulated using Cyclic Void Growth Model (CVGM) which is a micromechanics based fracture model. In each model, CVGM fracture index is calculated based on the stress and strain time histories and then models with different opening configurations are compared based on the calculated fracture index. In addition to the global models, sub-models with refined mesh are used to evaluate fracture index around the beam to column weldment. Modeling techniques are validated using data from previous experiments. Results show that as the perforation size increases, opening corners experience greater fracture index. This is while as the opening size increases the maximum observed fracture index at the connection welds decreases. However, the initiation of fracture at connection welds occurs at lower drift angles compared to opening corners. Finally, a probabilistic framework is applied to CVGM in order to account for the uncertainties existing in the prediction of ductile fracture and results are discussed.

Effect of In-Service Strengthening on the Axial Load Carrying Capacity of Steel Box Columns

Saeed Erfani,Mohsen Naseri,Vahid Akrami 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.1

To avoid any interruption of service and considering economic issues, strengthening of existing columns usually occurs while the member is under service loads. One of the important issues being neglected in the redesign process of retrofitted columns is the effects of significant axial load existing in the columns. This paper presents a numerical study to investigate the behavior and the ultimate bearing capacity of box shaped steel columns reinforced with continuous welded plates while under load. In the first phase of the study, it is intended to evaluate the variation of results with respect to the existing design relations. For this purpose, the ultimate bearing capacity of un-preloaded models is assumed to be in accordance with the selected design code and the corresponding geometric imperfection for each model is defined using several analyses to reach the values obtained with the design code, for further studies. In the second phase, the magnitude of initial imperfection is set to 1/500 of the studied columns. In both phases, the effect of magnitude of existing preload on ultimate bearing capacity is investigated considering two influential parameters, namely the slenderness ratio of the column and the ratio between cross sectional area of the column and reinforcing plates. Results show that by increasing the preload magnitude, the ultimate bearing capacity of reinforced columns with identical reinforcing plates, decreases. This reduction is more notable for the columns with median slenderness ratios. However, as the magnitude of preload increases, the effect of slenderness ratio on the reduction of ultimate bearing capacity becomes more evident. Also, it is found that by using a fixed imperfection ratio of L/500, even for un-preloaded models the ultimate bearing capacity of the strengthened column will be less than the values calculated as per the selected design code. Finally, an empirical relation is proposed to calculate reduction of ultimate bearing capacity for columns affected from various preload level considering different slenderness ratios.

Low-clock-speed time-interleaved architecture for a polar delta-sigma modulator transmitter

Nasser Erfani Majd,Rezvan Fani Electronics and Telecommunications Research Instit 2023 ETRI Journal Vol.45 No.1

The polar delta-sigma modulator (DSM) transmitter architecture exhibits good coding efficiency and can be used for software-defined radio applications. However, the necessity of high clock speed is one of the major drawbacks of using this transmitter architecture. This study proposes a low-complexity timeinterleaved architecture for the polar DSM transmitter baseband part to reduce the clock speed requirement of the polar DSM transmitter using an upsampling technique. Simulations show that using the proposed four-branch timeinterleaved polar DSM transmitter baseband part, the clock speed requirement of the transmitter is reduced by four times without degrading the signal-tonoise-and-distortion ratio.

Development and Psychometric Properties of an Extended Theory of Planned Behavior Questionnaire for Childbearing Intentions and Behaviors in Iran

Babak Moeini,Amir Erfani,Majid Barati,Amin Doosti-Irani,Hatam Hosseini,Mokhtar Soheylizad 대한가정의학회 2023 Korean Journal of Family Medicine Vol.44 No.2

Background: Childbearing is the most important determinant of population fluctuations, and its study is more im-portant than other population phenomena. Owing to the lack of a valid questionnaire based on the extended theo-ry of planned behavior, this mixed-method study was conducted to determine the validity and reliability of a ques-tionnaire designed to examine related belief-based factors on the intention to bear children in Iranian society.Methods: This study was conducted in two phases in Hamadan city, western Iran, in 2021. Phase 1 consisted of an extensive literature review and a qualitative study using a directed content analysis approach to generate an item pool. Psychometrics were measured in phase 2, including content, face, and construct validity. Reliability was as-sessed based on internal consistency and stability. The collected data were analyzed using IBM SPSS and AMOS ver. 24.0.Results: Mean content validity ratio and content validity index were 0.7 and 0.85, respectively. Exploratory factor analysis of the 32 items identified an eight-factor solution. These factors jointly accounted for 79.1% of the observed variance in the outcome variables. Confirmatory factor analysis indicated a good fit for the data. The internal con-sistency based on Cronbach’s α was 0.85 (0.71–0.93). In addition, stability was confirmed using the test-retest method and intraclass correlation coefficient (0.74–0.94).Conclusion: The designed questionnaire is a valid and reliable instrument for evaluating related belief-based fac-tors on the intention and behavior of childbearing among married men and women in Iran.

Application of Stem Cells in Targeted Therapy of Breast Cancer: A Systematic Review

Madjd, Zahra,Gheytanchi, Elmira,Erfani, Elham,Asadi-Lari, Mohsen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: The aim of this systematic review was to investigate whether stem cells could be effectively applied in targeted therapy of breast cancer. Material and Method: A systematic literature search was performed for original articles published from January 2007 until May 2012. Results: Nine studies met the inclusion criteria for phase I or II clinical trials, of which three used stem cells as vehicles, two trials used autologous hematopoetic stem cells and in four trials cancer stem cells were targeted. Mesenchymal stem cells (MSCs) were applied as cellular vehicles to transfer therapeutic agents. Cell therapy with MSC can successfully target resistant cancers. Cancer stem cells were selectively targeted via a proteasome-dependent suicide gene leading to tumor regression. $Wnt/{\beta}$-catenin signaling pathway has been also evidenced to be an attractive CSC-target. Conclusions: This systematic review focused on two different concepts of stem cells and breast cancer marking a turning point in the trials that applied stem cells as cellular vehicles for targeted delivery therapy as well as CSC-targeted therapies. Applying stem cells as targeted therapy could be an effective therapeutic approach for treatment of breast cancer in the clinic and in therapeutic marketing; however this needs to be confirmed with further clinical investigations.