Sharif Digital Repository

It is generally believed that the only utility of tests as a critical instrument is to be at the service of educational institutions. To broadly consider their different usefulness, tests can serve other purposes like focusing on the ethical and moral issues. As it is called Critical Language Testing, tests are not reliable instruments and they have the capacity of being used not only in educational, but also in political contexts. This philosophy has not been brought into perspective, and, as a result, the literature deserves more comprehensive attention. This study, guided by the principles of Grounded Theory and Qualitative research design, pursued three purposes: To investigate the... 

Autoencoder, as an essential part of many anomaly detection methods, is lacking flexibility on normal data in complex datasets. U-Net is proved to be effective for this purpose but overfits on the training data if trained by just using reconstruction error similar to other AE-based frameworks. Puzzle-solving, as a pretext task of self-supervised learning (SSL) methods, has earlier proved its ability in learning semantically meaningful features. We show that training U-Nets based on this task is an effective remedy that prevents overfitting and facilitates learning beyond pixel-level features. Shortcut solutions, however,are a big challenge in SSL tasks, including jigsaw puzzles. We propose... 

Increased uncertainty in the business environment as well as becoming modern and complicated have made supply chains more vulnerable to environmental disruptions than ever before. Due to their unpredictability, these disruptions can cause irreparable damage to supply chains and threaten their survival. Considering the novelty of the concept of e-commerce retail businesses in Iran, the importance of meeting customer expectations to boost the growth of these businesses, and the existence of many uncertainties in the business environment of these organizations, their supply chain resilience against disruptions is very important. Also, the importance of the role of logistics in meeting the... 

Traditional assumptions about assessment and learning have been challenged in higher education. Alternative types of assessment have been introduced to align to the students’ learning aims. Although, the growing body of literature of alternative types of assessment such as peer-assessment and self-assessment shed light on the advantages and benefits of embedding assessment in classroom activities, there is not absolute agreement on the consistency and accuracy of these types of assessment. To this aim, this study attempted to investigate the reliability and validity of self-assessment and peer-assessment of Iranian EFL learners’ written and oral production. The data was obtained from 32... 

Many real-world communication systems such as Internet, online social networks, and brain networks can be modeled as a complex network of interacting dynamical nodes. These networks have non-trivial topological features, i.e., features that do not occur in simple networks such as lattices or random networks. The tremendous growth of Internet and its applications in recent years has resulted in creation of large-scale complex networks involving tens or hundreds of millions of nodes and links. Thus, it may be impossible or costly to obtain a complete picture of these large networks, and sampling methods are essential for practical estimation of network properties. Therefore, in this thesis, we... 

Hyperspectral imaging is one of the remote sensing methods that has been widely applied in different applications. A hyperspectral image is composed of a set of pixels showing the spectral signatures in different frequency bands recorded by sensor cells. The process that detects the proportion of pure elements in the combination of pixels is called hyperspectral unmixing. Noisy and incomplete data, high mutual coherence of spectral libraries and different sensor settings are some challenges of the unmixing problem. In this work, we focus on semi-supervised linear hyperspectral unmixing in which a spectral library is given. The resulting linear equation is an underdetermind problem with... 

Red phosphorus, due to its unique chemical properties, and glycidol, with its reactive functional groups, provide an effective combination for synthesizing new copolymers with potential applications in biological fields, particularly in enzyme stabilization. In this study, a novel copolymer was synthesized using red phosphorus and glycidol through an anionic ring-opening mechanism. The synthesis process was confirmed using various analytical techniques, including FTIR, NMR, and thermal analyses, which demonstrated the successful incorporation of functional groups and an average phosphorus content of 40% in the copolymer. In the next step, modification of this copolymer by linking it to the... 

Main aim of this work was to obtain the harder zinc coating and increasing the anti corrosive properties by mean of adding SiO2 particles by electrophoretic method.
The coating was applied on the substrate surface by mean of electro co-deposition technique in three different electrolytes ethanol, methanol and water. The morphology of the coating in each electrolyte studied by scanning electron microscope (SEM).For the Zn/SiO2 coatings achieved in ethanol solvent the polarization and EIS tests was took place and found that for the Zn/SiO2 coating contain less than 10% SiO2 the corrosion rate decreased but for the coatings contains more than 10% SiO2 the paradox occurred because of the... 

Validation is an important enterprise especially when the test to be validated is a high-stakes one the results of which bring about life-changing implications for the candidates (Roever, 2001). Messick’s (1988) notion of construct irrelevant factors is pertinent in test validation. Demographic variables like gender, field of study and age can affect test results and interpretations. A fair test needs to be neutral when it comes to construct irrelevant factors such as gender. Differential Item Functioning is a way of making sure that the test does not favor one group of test takers over the others. The current study investigated differential item functioning (DIF) in terms of gender in the... 

The present study was conducted to examine the effect of explicit and implicit teaching of the speech acts of apologies and requests with 40 students. They were given a discourse completion test (DCT) which was designed by the researcher. The students came up with situations that embodied apologies and requests. After exemplar generation and likelihood investigation some 16 items were retained and used with students. The participants of the study consisted of two groups of implicit and explicit. The two groups were intact and randomization was not a possibility. The design was quasi-experimental. To investigate the relationship between grammatical competence and pragmatic competence, the... 

Despite the proven advantages of alternative assessment including self- and peer assessment, there is still uncertainty about the accuracy of these techniques especially in Iran since little research has conducted in this area. To this aim, a total of 2261 evaluation sheets were collected to investigate 118 peer assessments and 48 self-assessments of oral presentations in comparison with their teacher assessments. The data were collected during four semesters in general English classes held in Sharif University of Technology. Students were supposed to make an oral presentation for at least twenty minutes on a topic of their interest, and were then rated by their teacher, themselves, and... 

The relationship between travel behavior and Built Environment has been context of variety of research during past decades. Many modern urban development theories such as new-urbanism and smart growth are commonly based on interactions between these two concepts. This research is aiming to analyze the effects of built environment on household trip generation, mode and destination choice as specific indices of travel behavior, based on travel diary data of Shiraz city. Multiple Linear Regression and Multinomial Logit Model concepts are used to analyze aforementioned travel behaviors in two levels. Base models predict socio-economic variables importance and expanded models are used to test... 

The present study compares the reaction times in processing unambiguous sentences with three ambiguous statements of lexical, grouping and functional as well as garden path sentences. To this end, a special computer program was developed with the accuracy of micro seconds. Furthermore, a set of 25 items was prepared with acceptable levels of reliability and validity. Forty seven highly proficient subjects, all undergraduate students of Air Traffic Control, participated in this study. The results of the study showed no significant difference between the reaction times of grouping and functional ambiguities but garden path sentences showed the greatest difference with the other groups. All... 

Hydrogen sulfide, H2S, is a toxic gas and has detrimental effects on human health and the oil and gas industry. Therefore, its identification is very important. According to the devastating effects of this gas, then, the general mechanisms have been studied for gas detection. In addition, by highlighting the benefits of the multilayer nanostructure electrochemical sensors, an applicable and efficient method for the industrial production of these sensors has been investigated. In this regard, the sol-gel method is used to prepare the SnO2-CuO multilayer thin film and the advantages of this method was compared to PVD method. Also sensor properties of both deposition methods have been... 

The present research aims to examine the washback effect of TEFL M.A. entrance examination on university professors` and B.A English students` perceptions towards material preparation and instruction. With this end in view, a questionnaire and some interviews were used to gather information about the issue at point. The questionnaire includes a set of questions developed to help gain insight into the research questions. The interviews were held with B.A English state-university professors to provide additional and complementary information. The research tools enjoy expert judgment in terms of validity and as for the reliability, the questionnaire was proved to have an acceptable degree of... 

The present study was conducted to explore the effect of strategy based instruction and task based teaching on EFL learners’ production of apology and request speech acts and also to investigate the relationship between grammatical competence and speech act performance. To this end, 35 intermediate English language students that comprised two intact classes in a language institute participated in this study. A standard English proficiency test for intermediate level and a discourse completion task (DCT) were used to measure students’ grammatical competence and speech act production. DCT was used at the beginning of the study to ensure that the two classes were homogenous in terms of apology... 

The present study aims at examining interval scaling and magnitude estimation in grammaticality judgment tests in terms of reliability and validity. It also explores the probable impact of response formats on the participants’ performance. 30 Engineering students at Sharif university of Technology participated in this research. The instrument of the research is a grammaticality judgment test developed by Ellis (1990).Two computer-based programs were made in order to assess the two mentioned response formats in grammaticality judgment test. At the first phase of the study, the participants responded to the interval format and after an interval of one month, they attempted the second response... 

In the last decades, Reaction Time research has been extended to cognitive science and more specifically human information-processing research and has gained momentum (Shim, 1996). The present study examined the reaction time in processing marked and unmarked structures with regard to the four types of conditionals (considered as unmarked, less marked, marked and strongly markedness, respectively) and prepositions (preposition pied piping that is considered as unmarked and preposition stranding as marked). To this end, two softwares were developed for which the items relating to conditionals were chosen from the Bernet’s test (1985) and the ones pertinent to prepositions were taken from... 

Translation quality assessment (TQA) as a systematic field of inquiry has been under scholarly investigation over the past decades. In spite of the challenges appeared in the path to success, theoretical and practical developments have already been made in translation studies. One of the unsettled and challenging problems concerning translation assessment, yet, is the subjectivity that is inherent in the process of scoring test-takers’ translation performances. In the absence of any granular objective criteria which includes all the subcomponents of translation as a multi-layer rather than unitary construct, the raters inevitably bring their intuition and will to the act of measurement....