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31.
Social informatics research offers insights into the relationship between information technologies and social contexts. However, the material roles of information technologies, and their interplay with the agentic work of social actors, have not been addressed. Drawing on a field study of 37 mobile knowledge workers, we examine the dual material roles (enabling and constraining) played by information technologies in their work practices. We also investigate how these workers exert agency by fashioning multiple information technologies into a functioning digital assemblage. Although information technologies provide consequential affordances that enable mobilization of work across spaces and times, they simultaneously present design-driven, local, organizational, and temporal technological constraints that require mobile knowledge workers to engage in “configuration work” to make information technologies function effectively. Building on a sociomaterial perspective, we further discuss the interplay of information technologies and work practices enacted by mobile knowledge workers, in which both human and technological agency are materialized. 相似文献
32.
Huda Karajeh Mahmoud Maqableh Lama Rajab Hiba Mohammad Tahani Khatib Nabeel Al-Qirim Ali Tarhini 《Education and Information Technologies》2018,23(5):2073-2090
This study examined impact of a social media networks course on student use of SNSs performance. Moreover, it examined the associations among course design, course materials, learning experiences and a social media networks course. Survey instrument is used to examine the relationships in the proposed model. A total of 380 questionnaires have been collected from students at the University of Jordan who studied the social media networks course. A structural equation modelling approach based on AMOS 20.0 statistical software is used to study the causal relationships and test the hypotheses between the observed and latent constructs in the proposed research model. The analysis results revealed that course materials and learning experiences directly, positively and significantly impacted the social media networks course, which in turn had a significant impact on students’ use social networks sites performance. Course design, however, did not impact the social media networks course. Our findings have important implications as we demonstrated the validity of the joint two different models and provide information about impact of studying social media networks course on students’ academic performance. 相似文献
33.
Pejhman Ghassemi Mohammad Hossein Miranbaygi 《Journal of Zhejiang University. Science. B》2009,10(8):602-608
Measurement of optical properties of skin is an expanding and growing field of research. Recent studies have shown that the
biological tissue, especially skin, changes the polarization state of the incident light. Using this property will enable
the study of abnormalities and diseases that alter not only the light intensity but also its polarization state. In this paper
we report an experimental study for measuring changes of polarization state of the light scattered from a phantom similar
to a sample model of scattering skin. Using the notation of Stokes vector for the polarized light and Mueller matrix for the
sample with its polarization properties, we have shown that some elements of the matrix were particularly sensitive to the
changes of the polarization-altering physical properties of the scatterers within the phantom.
相似文献
34.
Characterization of a-Si:H/SiN multilayer waveguide polarization using an optical pumping application—LED 总被引:1,自引:1,他引:0
Mohd Saiful Dzulkefly Zan Isamu Kato Mohammad Syuhaimi Ab-Rahman Seri Mastura Mustaza 《浙江大学学报(A卷英文版)》2009,10(10):1421-1427
This paper describes the fabrication of a waveguide and the analysis of its polarization characteristics by applying light-emitting diode (LED) pumping lights to its surface. By using double tubed coaxial line (DTCL) microwave plasma chemical vapor deposition (MPCVD) equipment, an a-Si:H/SiN multilayer waveguide was fabricated whose thickness could be controlled at nanometer order. The main structural material of the waveguide sample consisted of a combination of layers of amorphous silicon hydrogen and silicon nitrate. Once the sample was ready, another major objective of the experiment was to analyze the polarization characteristics of the fabricated waveguide. The idea of the experiment was to analyze how the waveguide reacts when three types of LED (blue, yellow, and red) are radiated onto its surface. The results showed that the fabrication of the a-Si:H/SiN sample is successful. Most effective transmission results, which accord with the polarization characteristics analysis, were obtained. 相似文献
35.
Bahram Vazirnezhad Farshad Almasganj Seyed Mohammad Ahadi Ari Chanen 《浙江大学学报(A卷英文版)》2009,10(10):1461-1475
Speaker variability is an important source of speech variations which makes continuous speech recognition a difficult task. Adapting automatic speech recognition (ASR) models to the speaker variations is a well-known strategy to cope with the challenge, Almost all such techniques focus on developing adaptation solutions within the acoustic models of the ASR systems. Although variations of the acoustic features constitute an important portion of the inter-speaker variations, they do not cover variations at the phonetic level. Phonetic variations are known to form an important part of variations which are influenced by both micro-segmental and suprasegmental factors. Inter-speaker phonetic variations are influenced by the structure and anatomy of a speaker's articulatory system and also his/her speaking style which is driven by many speaker background characteristics such as accent, gender, age, socioeconomic and educational class. The effect of inter-speaker variations in the feature space may cause explicit phone recognition errors. These errors can be compensated later by having appropriate pronunciation variants for the lexicon entries which consider likely phone misclassifications besides pronunciation. In this paper, we introduce speaker adaptive dynamic pronunciation models, which generate different lexicons for various speaker clusters and different ranges of speech rate. The models are hybrids of speaker adapted contextual rules and dynamic generalized decision trees, which take into account word phonological structures, rate of speech, unigram probabilities and stress to generate pronunciation variants of words. Employing the set of speaker adapted dynamic lexicons in a Farsi (Persian) continuous speech recognition task results in word error rate reductions of as much as 10.1% in a speaker-dependent scenario and 7.4% in a speaker-independent scenario. 相似文献
36.
Michel Laroche Mohammad Reza Habibi Marie-Odile Richard 《International Journal of Information Management》2013
There is an ongoing debate over the activities of brands and companies in social media. Some researchers believe social media provide a unique opportunity for brands to foster their relationships with customers, while others believe the contrary. Taking the perspective of the brand community building plus the brand trust and loyalty literatures, our goal is to show how brand communities based on social media influence elements of the customer centric model (i.e., the relationships among focal customer and brand, product, company, and other customers) and brand loyalty. A survey-based empirical study with 441 respondents was conducted. The results of structural equation modeling show that brand communities established on social media have positive effects on customer/product, customer/brand, customer/company and customer/other customers relationships, which in turn have positive effects on brand trust, and trust has positive effects on brand loyalty. We find that brand trust has a fully mediating role in converting the effects of enhanced relationships in brand community to brand loyalty. The implications for marketing practice and future research are discussed. 相似文献
37.
Mohammad Taha Jalali Abdolhosain Mosavi Honomaror Abdolkarim Rekabi Mahmod Latifi 《Indian journal of clinical biochemistry : IJCB》2013,28(3):277-282
Cardiovascular diseases (CVD) are recognized as major mortality causes and imposes tremendously heavy socio-economic burden worldwide. A vast variety of risk factors have been introduced in the literature known to enhance the incidence of CVD, such as hyperlipidemia. Therefore in order to make an accurate clinical decision it is essential to have appropriate reference ranges for lipids and lipoprotein particles in a particular population. Healthy female (n = 601) and male (n = 617) cases were randomly selected according to certain exclusion criteria from individuals visiting the major University hospital clinics situated in different part of Ahvaz city, Iran, from June 2010 to December 2010. Fasting blood samples (10 ml) were collected and analyzed for total cholesterol, total triglyceride and HDL-C employing enzymatic assays of CHOD-PAP, GPO-PAP and homogenous methods respectively. The samples were obtained such to include the ethnic populations of Persian, Arab. Lore leaving in this city. The data were analyzed statistically by SPSS-18 software. The obtained results were analyzed then age ethnic-wise and reference ranges (mean ± 1SD) were calculated. Remarkable differences between the obtained results for our population with other nations were seen. Also ethnic difference for HDL-C among our cases was noted. The observed significant differences among different nations and ethnicities emphasizes the need for nation-specific, local reference ranges for lipids and lipoproteins particles, to be established. 相似文献
38.
Average-ability students often do not take full advantage of learning in mixed-ability groups because they hardly engage in the group interaction. This study examined whether structuring collaboration by group roles and ground rules for helping behavior might help overcome this participatory inequality. In a plant biology course, heterogeneously grouped fourth-grade boys (n=164) were randomly assigned to a structured collaboration condition or an unconstrained comparison condition. Results indicated positive effects of structured collaboration on average-ability students’ achievement, motivation, and contribution to the group interaction. Another positive result was that structuring collaboration did not lower the scores of the high and low-ability students on these measures. 相似文献
39.
Omid Noroozi Armin Weinberger Harm J.A. Biemans Martin Mulder Mohammad Chizari 《Educational Research Review》2012,7(2):79-106
Learning to argue is an essential objective in education; and online environments have been found to support the sharing, constructing, and representing of arguments in multiple formats for what has been termed Argumentation-Based Computer Supported Collaborative Learning (ABCSCL). The purpose of this review is to give an overview of research in the field of ABCSCL and to synthesize the findings. For this review, 108 publications (89 empirical studies and 19 conceptual papers) on ABCSCL research dating from 1995 through 2011 were studied to highlight the foci of the past 15 years. Building on Biggs’ (2003) model, the ABCSCL publications were systematically categorized with respect to student prerequisites, learning environment, processes, and outcomes. Based on the quantitative and qualitative findings, this paper concludes that ABCSCL environments should be designed in a systematic way that takes the variety of specific conditions for learning into account. It also offers suggestions for educational practice and future research. 相似文献
40.
Omid Noroozi Maria C. Busstra Martin Mulder Harm J. A. Biemans Hilde Tobi Anouk Geelen Pieter van’t Veer Mohammad Chizari 《Educational technology research and development : ETR & D》2012,60(2):193-221
This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation
(information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and
type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student
knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment
in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction
than those who received information only before each cluster. The students within the two separate information presentation
conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion
or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster,
online discussion led to better results than personal discussion. When supportive information had been presented during the
learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction.
Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the
learning task clusters in IDLM. 相似文献