Stable model predictive control for a nonlinear system     

Akbar Rahideh  M. Hasan Shaheed 《Journal of The Franklin Institute》2011,348(8):1983-2004

In this paper, a stable model predictive control approach is proposed for constrained highly nonlinear systems. The technique is a modification of the multistep Newton-type control strategy, which was introduced by Li and Biegler. The proposed control technique is applied on a constrained highly nonlinear aerodynamic test bed, the twin rotor MIMO system (TRMS) to show the efficacy of the control technique. Since the accuracy of the plant model is vital in MPC techniques, the nonlinear state space equations of the system are derived considering all possible effective components. The nonlinear model is adaptively linearized during the prediction horizon. The linearized models of the system are employed to form a linear quadratic objective function subject to a set of inequality constraints due to the system input/output limits. The stability of the control system is guaranteed using the terminal equality constraints technique. The satisfactory performance of the proposed control algorithm on the TRMS validates the effectiveness and the reliability of the approach.  相似文献   

Promotion and Knowledge of Online Patent Literature Search to Enhance Scientific Output in Tanzania: Case of Two Universities in Zanzibar     

Abbas Mohamed Omar  Haji Ali Haji  Juliana James Manyerere 《International Information and Library Review》2020,52(1):1-9

Abstract

This study examines the promotion and knowledge of online patent literature search among students, librarians, and instructors to enhance university scientific output in Zanzibar. The study was guided by four key questions: What is the level of awareness of students, instructors and library staff about patent documents as source of information? To what extent do students and instructors access online patent databases? What is the library experience in training students about online patent literature searching?, and what are the challenges facing library and instructors in promoting patent literature search? The study used survey approach whereby questionnaire and interview were used to collect data. The recent literatures regarding online patent literature searching were also critically reviewed. A survey was conducted at two Universities in Zanzibar namely the State University of Zanzibar and Zanzibar University, whereby 20 library staff, 10 instructors and 140 undergraduate students from the School of Computing and the Faculty of Engineering were involved in this study. The findings show that more than three quarters of respondents were either partially aware or not aware at all about the existence of free online patent databases. Likewise, the majority of students had no enough skills of patent literature searching. However, usually the library organizes training on general online literature searching skills but patent literature searching was not effectively taught and a big challenge observed in this study regarding promotion of patent literature searching is inadequate patent searching skills among library and instructors. Based on the findings, the study proposed several recommendations to rectify the existing problem.  相似文献   

Enhancing Aspect-Based Sentiment Analysis of Arabic Hotels’ reviews using morphological,syntactic and semantic features     

Mohammad Al-Smadi  Mahmoud Al-Ayyoub  Yaser Jararweh  Omar Qawasmeh 《Information processing & management》2019,56(2):308-319

This research presents an enhanced approach for Aspect-Based Sentiment Analysis (ABSA) of Hotels’ Arabic reviews using supervised machine learning. The proposed approach employs a state-of-the-art research of training a set of classifiers with morphological, syntactic, and semantic features to address the research tasks namely: (a) T1:Aspect Category Identification, (b) T2:Opinion Target Expression (OTE) Extraction, and (c) T3: Sentiment Polarity Identification. Employed classifiers include Naïve Bayes, Bayes Networks, Decision Tree, K-Nearest Neighbor (K-NN), and Support-Vector Machine (SVM).The approach was evaluated using a reference dataset based on Semantic Evaluation 2016 workshop (SemEval-2016: Task-5). Results show that the supervised learning approach outperforms related work evaluated using the same dataset. More precisely, evaluation results show that all classifiers in the proposed approach outperform the baseline approach, and the overall enhancement for the best performing classifier (SVM) is around 53% for T1, around 59% for T2, and around 19% in T3.  相似文献   

Wellbeing and Policy     

Hasan Bakhshi 《Cultural Trends》2014,23(4):304-307

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Authorship conflict in Bangladesh: an exploratory study     

Hasan Shareef AHMED  Abdullahel HADI  Nuzhat CHOUDHURY 《Learned Publishing》2010,23(4):319-325

This study aimed to explore the causes, types, and consequences of authorship conflicts among the researchers of selected research institutions in Dhaka, Bangladesh; and to suggest ways to reduce conflicts. A sample of 100 researchers was given a semi‐structured questionnaire; 45 subjects responded. The responses were confidential and anonymous. Over two‐thirds of the respondents were aware of authorship conflicts, and one‐third had actually faced conflicts with their co‐authors. Of them, four faced conflicts with their juniors, while 13 faced conflicts with their seniors or supervisors. The primary causes of such conflicts appear to be unethical claims of authorship, violation of authorship order, and deprivation of authorship. In most cases, the victims became frustrated and had to give up, and avoided a direct clash to safeguard their job. Four respondents claimed to have been victimized for raising their voice. Conflict was never resolved in seven cases. To reduce conflicts, respondents suggested that authorship should be decided before the study begins, order of authorship must be determined according to contribution, and a standard code of authorship should be followed strictly. Authorship conflicts arise among researchers mostly due to what they regard as unethical practice of their co‐authors, supervisors, and department heads in the absence of any formal authorship policy in the institutions. A standard code of authorship, sensitization of researchers to the problem through open discussions and advocacy, and formation of a grievance redress committee are suggested to minimize such conflicts. Although the sample size was small, some of the specific recommendations will be appropriate in many other cases.  相似文献   

Maximal lactate steady state in trained adolescent runners     

Almarwaey OA  Jones AM  Tolfrey K 《Journal of sports sciences》2004,22(2):215-225

The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake (VO2). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0 mmol x l(-1) were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5 km x h(-1), where the change in blood lactate concentration between 10 and 20 min was < 0.5 mmol x l(-1). Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3 km x h(-1), P < 0.01), once the data were expressed relative to percent peak VO2 (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P > 0.05). The running speed and percent peak VO2 at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5 mmol x l(-1) (P > 0.05), but were both lower than those at the 4.0 mmol x l(-1) concentration (P < 0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak VO2 and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5 mmol x l(-1) measured during an incremental treadmill test in boys and girls.  相似文献   

The ethics of chemical hazard     

Sattaur O 《New scientist (1971)》1985,108(1481):66-67

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Using Hands-On and Virtual Laboratories Alone or Together―Which Works Better for Acquiring Knowledge and Skills?     

Kapici  Hasan Ozgur  Akcay  Hakan  de Jong  Ton 《Journal of Science Education and Technology》2019,28(3):231-250

Journal of Science Education and Technology - Although hands-on laboratory experiments are traditionally used in schools, virtual laboratories have entered today’s classrooms, due to their...  相似文献   

Searching for Components of Conceptual Ecology That Mediate Development of Epistemological Beliefs in Science     

Hasan Deniz 《Journal of Science Education and Technology》2011,20(6):743-749

This paper articulates the importance of epistemological beliefs (EBs) and draws a parallel between EBs literature in educational psychology and nature of science (NOS) literature in science education. The paper stresses that EBs in science and NOS ideas have common ground and they can be best improved through explicit-reflective instruction informed by conceptual change theory. The paper concludes that future studies should explore the factors that mediate the development of EBs in science and NOS ideas rather than documenting the changes in students’ and teachers’ EBs in science and NOS ideas after explicit-reflective instruction through pre- and post assessments.  相似文献   

Effectiveness of Computer-Based Chemistry Instruction in Enhancing the Learning of Content and Variable Control Under Guided Versus Unguided Conditions     

Ardac  Dilek  Sezen  Ali Hasan 《Journal of Science Education and Technology》2002,11(1):39-48

Computerized learning environments offer several possibilities that can be used to improve the teaching of content along with the process. Research indicates that students benefit from additional guidance, particularly when computer-based instruction requires active construction of knowledge. This study examines the relative effectiveness of guided versus unguided computer-based instruction with respect to regular instruction in improving content knowledge and process skills among students with low and high chemistry achievement levels. The results indicate that the effectiveness of computer-based instruction increases when learning is supported by teacher-directed guidance. Computer-based instruction (with or without guidance) was observed to be more effective than regular instruction in improving process skills particularly for students with high chemistry achievement. However, although the students who received regular or guided computer-based instruction showed significant gains in content knowledge, students under unguided condition failed to construct the expected content knowledge.  相似文献