A novel controller for nonlinear uncertain systems using a combination of SDRE and function approximation technique: Regulation and tracking of flexible-joint manipulators     

Neda Nasiri  Ahmad Fakharian  Mohammad Bagher Menhaj 《Journal of The Franklin Institute》2021,358(10):5185-5212

This paper presents a novel combined State Dependent Riccati Equation (SDRE) / Function Approximation Technique (FAT)-based control design for nonlinear uncertain systems. The SDRE is employed to construct an optimal controller and the function approximation technique is utilized to estimate time-varying disturbances and uncertainties. Moreover, a robust term in the proposed control law compensates for the truncation error. The closed-loop stability and boundedness of the tracking error and FAT weights approximation error are proved in the sense of Lyapunov, with consideration of truncation error. Due to the great importance of the adequate performance of transient response from practical point of view, performance evaluation has been accomplished. The proposed scheme is computationally simple due to utilizing the FAT to represent uncertainties and disturbances as a function of time. Compared with the SDRE based SMC, the proposed controller is superior in terms of capability to track a fast and highly complicated trajectory and no need to determine time-varying disturbances and uncertainties bounds. The case study is a Selective Compliant Articulated Robot for Assembly (SCARA) flexible joint manipulator as a representative of highly nonlinear, coupled, large robotic systems. Simulation results easily verify the effectiveness and superiority of the proposed controller.  相似文献   

SCiMet: Stable,sCalable and reliable Metric-based framework for quality assessment in collaborative content generation systems     

Mohammad Allahbakhsh  Haleh Amintoosi  Behshid Behkamal  Amin Beheshti  Elisa Bertino 《Journal of Informetrics》2021,15(2):101127

In collaborative content generation (CCG), such as publishing scientific articles, a group of contributors collaboratively generates artifacts available through a venue. The main concern in such systems is the quality. A remarkable range of research considers quality metrics partially when dealing with the quality of artifacts, contributors, and venues. However, such approaches have several drawbacks. One of the most notable ones is that they are not comprehensive in terms of the metrics to evaluate all entities, including artifacts, contributors, and venues. Also, they are vulnerable to potential attacks.In this paper, we propose a novel iterative definition in which the quality of artifacts, collaborators, and venues are defined interconnectedly. In our framework, the quality of an artifact is defined based on the quality of its contributors, venue, references, and citations. The quality of a contributor is defined based on the quality of his artifacts, collaborators, and the venues. Quality of a venue is defined based on both quality of artifacts and contributors. We propose a data model, formulations, and an algorithm for the proposed approach. We also compare the robustness of our approach against malicious manipulations with two well-known related approaches. The comparison results show the superiority of our method over other related approaches.  相似文献   

The effects of socio-demographic factors on physical activity in gated and non-gated neighbourhoods in Karachi,Pakistan     

Yasmeen Gul  Zahid Sultan  Mehdi Moeinaddini  Gul Ahmed Jokhio 《Sport in Society》2019,22(7):1225-1239

Physical activity (PA) is important in ensuring a healthy population. It is dependent on various socio-demographic (SD) factors, such as age, gender, employment and marital status. A limited number of studies have investigated the relationship between SD factors and PA but research exploring this relationship from the perspective of gated and non-gated neighbourhoods is scarcer. Therefore, the objective of this study is to investigate the relationship between SD factors and PA variables in gated and nongated neighbourhoods in Karachi Pakistan. Results of the independent sample t-test and Pearson chi-square showed that young and single people do more sports activities in gated neighbourhoods. Women, unemployed people and public transport users walk more in non-gated neighbourhoods. In conclusion, future neighbourhoods should have more pedestrian friendly areas and a larger number of PA facilities, rather than building more walls and gates.  相似文献   

Editors’ note     

Patrick Burkart  Miyase Christensen  Mehdi Semati  Nabeel Zuberi 《Popular Communication》2016,14(4):195-198

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21st Century experiences in the development of school-based management policy and practices in Indonesia     

Bandur  Agustinus  Hamsal  Mohammad  Furinto  Asnan 《Educational Research for Policy and Practice》2022,21(1):85-107

Educational Research for Policy and Practice - Since 2001, Indonesian schools have implemented a mandatory school-based management (SBM) policy for better quality education in general and more...  相似文献   

Multimodal learning analytics—In-between student privacy and encroachment: A systematic review     

Paul Prinsloo  Sharon Slade  Mohammad Khalil 《British journal of educational technology : journal of the Council for Educational Technology》2023,54(6):1566-1586

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Understanding privacy and data protection issues in learning analytics using a systematic review     

Qinyi Liu  Mohammad Khalil 《British journal of educational technology : journal of the Council for Educational Technology》2023,54(6):1715-1747

The field of learning analytics has advanced from infancy stages into a more practical domain, where tangible solutions are being implemented. Nevertheless, the field has encountered numerous privacy and data protection issues that have garnered significant and growing attention. In this systematic review, four databases were searched concerning privacy and data protection issues of learning analytics. A final corpus of 47 papers published in top educational technology journals was selected after running an eligibility check. An analysis of the final corpus was carried out to answer the following three research questions: (1) What are the privacy and data protection issues in learning analytics? (2) What are the similarities and differences between the views of stakeholders from different backgrounds on privacy and data protection issues in learning analytics? (3) How have previous approaches attempted to address privacy and data protection issues? The results of the systematic review show that there are eight distinct, intertwined privacy and data protection issues that cut across the learning analytics cycle. There are both cross-regional similarities and three sets of differences in stakeholder perceptions towards privacy and data protection in learning analytics. With regard to previous attempts to approach privacy and data protection issues in learning analytics, there is a notable dearth of applied evidence, which impedes the assessment of their effectiveness. The findings of our paper suggest that privacy and data protection issues should not be relaxed at any point in the implementation of learning analytics, as these issues persist throughout the learning analytics development cycle. One key implication of this review suggests that solutions to privacy and data protection issues in learning analytics should be more evidence-based, thereby increasing the trustworthiness of learning analytics and its usefulness.

Practitioner notes

What is already known about this topic

• Research on privacy and data protection in learning analytics has become a recognised challenge that hinders the further expansion of learning analytics.
• Proposals to counter the privacy and data protection issues in learning analytics are blurry; there is a lack of a summary of previously proposed solutions.

What this study contributes

• Establishment of what privacy and data protection issues exist at different phases of the learning analytics cycle.
• Identification of how different stakeholders view privacy, similarities and differences, and what factors influence their views.
• Evaluation and comparison of previously proposed solutions that attempt to address privacy and data protection in learning analytics.

Implications for practice and/or policy

• Privacy and data protection issues need to be viewed in the context of the entire cycle of learning analytics.
• Stakeholder views on privacy and data protection in learning analytics have commonalities across contexts and differences that can arise within the same context. Before implementing learning analytics, targeted research should be conducted with stakeholders.
• Solutions that attempt to address privacy and data protection issues in learning analytics should be put into practice as far as possible to better test their usefulness.

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