Exact performance analysis of OS modified versions with noncoherent integration in nonideal situations     

Mohamed B. El Mashade 《Journal of The Franklin Institute》2005,342(5):521-550

The radar signals returning from the targets being illuminated are usually accompanied by thermal noise and clutter. Constant false alarm rate (CFAR) processors are useful for detecting these targets in a background for which the parameters of the statistical distribution are not known and may be nonstationary. The ordered-statistics (OS) CFAR technique has been proven to work satisfactorily in both multiple-target and nonuniform clutter cases. Unfortunately, the large processing time taken by this scheme limits its practical uses. The modified versions of the OS processor have been proposed to replace it in these applications. They can reduce the processing time of the single-window OS detector in half without changing its useful properties. Our goal in this paper is to provide a complete detection analysis for the OS processor along with ordered-statistic greatest-of (OSGO) and ordered-statistic smallest-of (OSSO) modified versions, for M postdetection integrated pulses when the operating environment is nonideal. Analytical results of performance are presented in both multiple-target situations and in regions of clutter power transitions. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the Swerling II target fluctuation model. As the number of noncoherently integrated pulses increases, lower threshold values and consequently better detection performances are obtained in both homogeneous and multiple-target background models. However, the false alarm rate performance of OSSO-CFAR scheme at clutter edges worsens with increasing the postdetection integrated pulses. As predicted, the OSGO-CFAR detector accommodates the presence of spurious targets in the reference window, given that their number is within its allowable range in each local window, and controls the rate of false alarm when the contents of the reference cells have clutter boundaries. The OSSO-CFAR scheme is useful in the situation where there is a cluster of radar targets amongst the estimation cells.  相似文献   

Mobile learning as alternative to assistive technology devices for special needs students     

Jalal Ismaili  El Houcine Ouazzani Ibrahimi 《Education and Information Technologies》2017,22(3):883-899

Assistive Technology (AT) revolutionized the process of learning for special needs students during the past three decades. Thanks to this technology, accessibility and educational inclusion became attainable more than any time in the history of special education. Meanwhile, assistive technology devices remain unreachable for a large number of students with disabilities, especially in under-developed and developing countries like Morocco due to a number of factors, especially, availability and affordability. Mobile learning, using smartphones and tablets in particular, may provide alternative solutions as special education tools in such countries. Additionally, open source platforms, particularly Google play store with all the applications it accommodates for disabled people, may obviate the need for monofunctional, sometimes expensive, AT devices. The present paper sets out to investigate potentials of using smartphones and tablets as alternative learning tools for assistive technology devices within formal and informal learning environments. It compares seven free Google Play medical apps with seven assistive technology devices at the level of functionality and affordability. The apps are of relevance to cases of physical as well as mental disabilities, namely hearing impairment, visual impairment, autism and speech articulation disorders.  相似文献   

Pedler,Mike & Abbott,Christine (2013) Facilitating action learning McGraw‐Hill (Maidenhead & New York) isbn 978‐033524597‐0 204 pp £19.99 http://www.mheducation.co.uk/9780335245970‐emea‐facilitating‐action‐learning‐a‐practitioners‐guide          下载免费PDF全文

Dr Nancy El‐Farargy 《British journal of educational technology : journal of the Council for Educational Technology》2015,46(4):E17-E18

This most helpful book supports action learning practitioners in organising collaborative working and knowledge generation and implementation. The case studies help inspire and motivate readers to take action, and the book as a whole leans towards practical guidance rather than being loaded with theory. It's a readable text for aspiring action learning practitioners aiming to drive forward and implement such ideas, and to share learning at system‐wide scale. It also serves as a quick reference guide for the personal libraries of more seasoned practitioners and other leaders and developers. If the content of this book is likely to be relevant to you, I recommend that you buy a copy for your own use. Nancy El‐Farargy  相似文献   

Improvement in Student Performance and Perceptions through a Flipped Anatomy Classroom: Shifting from Passive Traditional to Active Blended Learning     

Abir El Sadik  Waleed Al Abdulmonem 《Anatomical sciences education》2021,14(4):482-490

One of the major challenges facing anatomy educators is delivering the anatomy materials in fewer hours with a reduction of anatomy courses in the integrated curricula. The flipped classroom modality may be an innovative solution. However, its effectiveness remains under debate due to a lack of outcome-based research and the mixed results of students' performance. The present study aimed to determine the outcome of the flipped classroom based upon the level of student cognition. The study investigated performance on 17 multiple-choice anatomy questions as a part of the final examination of the musculoskeletal system module. The results were compared between the first-year female students of Qassim Medical College, specifically the flipped classroom group (46 students) of the academic year (2018–2019) and the traditional group (49 students) of the academic year (2017–2018). The mean differences in the students' grades on the anatomy questions at the level of knowledge, application, and analysis using Cohen's d test were 0.43, 1.41, and 1.01, respectively. These results suggest the positive impact of flipping the students' classrooms on improving their levels of thinking according to Bloom's taxonomy. Perception surveys also revealed students' enthusiasm for the pre-class activities, leading to a better performance in the class with more engagement with their peers and teachers. The present study suggested that the flipped classroom modality can be performed to compensate for the reduction of anatomy educational hours. However, further studies are recommended to investigate the best practices of the flipped classroom that fit with the students' needs and workloads.  相似文献   

Some Reflections about the Use of the Berber Language in the Medieval and Early Modern Maghrib: Data from Hagiographic Sources     

Rachid El Hour 《Al-Masaq: Islam & the Medieval Mediterranean》2014,26(3):288-298

The Berber language has historically been a key element in the socio-cultural and ethnic fabric of the Maghrib. Consequently, in recent years there have been several initiatives to recover and interpret the information Arabic sources provide on the Berber language and the role played by Berber peoples in the consolidation of Islam in this area.

Studies of the Berber language and peoples have primarily centred on chronicles and geographical sources, but scholars have devoted less attention to other sources, especially hagiographies. With the exception of some specific work, the role of the Berber language and peoples in hagiographic literature has not been systematically analysed. The analysis presented in this article suggests that some hagiographic sources, especially those written by Berber authors, while avoiding an open defence of Berber identity, in fact hid it behind comments and quotes of a linguistic nature. This study, although it includes some additional references to the Mārinid, Wa??āsid and Sa?did periods, concentrates on the Almohads, and deals with written sources, both Andalusi and Maghribi.  相似文献   

Leveraging textual properties of bug reports to localize relevant source files     

Reza Gharibi  Amir Hossein Rasekh  Mohammad Hadi Sadreddini  Seyed Mostafa Fakhrahmad 《Information processing & management》2018,54(6):1058-1076

Bug reports are an essential part of a software project's life cycle since resolving them improves the project's quality. When a new bug report is received, developers usually need to reproduce the bug and perform code review to locate the bug and assign it to be fixed. However, the huge number of bug reports and the increasing size of software projects make this process tedious and time-consuming. To solve this issue, bug localization techniques try to rank all the source files of a project with respect to how likely they are to contain a bug. This process reduces the search space of source files and helps developers to find relevant source files quicker. In this paper, we propose a multi-component bug localization approach that leverages different textual properties of bug reports and source files as well as the relations between previously fixed bug reports and a newly received one. Our approach uses information retrieval, textual matching, stack trace analysis, and multi-label classification to improve the performance of bug localization. We evaluate the performance of the proposed approach on three open source software projects (i.e., AspectJ, SWT, and ZXing) and the results show that it can rank appropriate source files for more than 52% of bugs by recommending only one source file and 78% by recommending ten files. It also improves the MRR and MAP values compared to several existing state-of-the-art bug localization approaches.  相似文献   

Linguistic aggregation methods in blog retrieval     

Mostafa Keikha  Fabio Crestani 《Information processing & management》2012

This paper addresses the blog distillation problem, that is, given a user query find the blogs that are most related to the query topic. We model each post as evidence of the relevance of a blog to the query, and use aggregation methods like Ordered Weighted Averaging (OWA) operators to combine the evidence. We show that using only highly relevant evidence (posts) for each blog can result in an effective retrieval system. We also take into account the importance of the posts in a query-based cluster and investigate its effect in the aggregation results. We use prioritized OWA operators and show that considering the importance is effective when the number of aggregated posts from each blog is high. We carry out our experiments on three different data sets (TREC07, TREC08 and TREC09) and show statistically significant improvements over state of the art model called voting model.  相似文献   

Robust adaptive finite-time stabilization control for a class of nonlinear switched systems based on finite-time disturbance observer     

Mohammad Javad Mirzaei  Ehsan Aslmostafa  Mostafa Asadollahi  Mohammad Ali Badamchizadeh 《Journal of The Franklin Institute》2021,358(7):3332-3352

The problem of adaptive global finite-time stabilization control for a class of nonlinear switched systems in the presence of external perturbations and arbitrary switchings has been addressed in this research study. The proposed scheme has been designed based on a finite-time estimation technique in which during the control procedure, unknown imposed perturbations are accurately estimated by means of the designed finite-time disturbance observer (FTDO). Due to the exact estimation of the external disturbances within a given finite time, the encountered complications and adversities from loss of information in the Lyapunov parameter estimation (LPE) methods have been solved which are caused by the persistent switchings in the system. Furthermore, a new solution for the problem of chattering phenomenon in nonlinear switched systems has been presented by utilizing the designed FTDO, which can counteract the malfunctioning responses of the system caused by external disturbances and unmodeled dynamics. In this paper, an acknowledged class of nonlinear switched systems has been taken into account which is in the general form of canonical structure. In addition, the established design strategy is formulated for the control of perturbed nonlinear switched systems with one and only input and assures that the system states through the finite-time convergence characteristic, reach the equilibrium point of origin. Finally, numerical simulations are carried out on a mass-spring-damper (MSD) dynamical system to indicate advantages and superior efficiency of the suggested method.  相似文献   

Richey,Rita C ed (2013) Encyclopedia of terminology for educational communications and technology Springer (Berlin) isbn 978‐1‐4614‐6572‐0 xxxii+338 pp £117 http://www.springer.com/education+%26+language/learning+%26+instruction/book/978‐1‐4614‐6572‐0     

Nancy El‐Farargy 《British journal of educational technology : journal of the Council for Educational Technology》2014,45(3):E17-E18

This collection of explanations of terms across the field of educational communications and technology offers scholars and practitioners a comprehensive and coherent overview of the domain. It presents short key educational discussions, annotated explanations, and avenues to further scholarly works. I recommend borrowing the book, and for educational leaders, it could fruitfully feature as a useful reference text in their personal libraries. Nancy El‐Farargy  相似文献   

Trends in the development of student level of reasoning in pattern generalization tasks across grade level     

Murad Eid Jurdak  Rabih Raif El Mouhayar 《Educational Studies in Mathematics》2014,85(1):75-92

This paper explored (1) the developmental trend of student level of reasoning across grade level in pattern generalization; (2) the mediatory role of task variables in the developmental trend of student level of reasoning within and across tasks; and (3) developmental trend of student level of reasoning associated with strategy use across grade level. A test designed to measure student level of reasoning was given to a sample of 1232 students from grades 4 to 11 from 5 schools in Lebanon. The Structure of the Learned Outcomes or Responses (SOLO) was used as a theoretical model. Results show that student level of reasoning exhibited an increasing trend across clusters of grade levels and that there were several SOLO levels in each cluster of grade levels. Type of task (immediate, near, far) and function type (linear, non-linear) seem to mediate the development of level of reasoning across grade level but the complexity of the task (simple, more complex) did not. Students used several strategies in each cluster of grade levels and the developmental trends of student level of reasoning associated with strategy use were not uniform and varied across clusters of grade levels, thus supporting a neo-Piagetian interpretation of the results.  相似文献