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Yousaf HAYAT 《Journal of Zhejiang University. Science. B》2008,9(12):931-937
A method was proposed for the detection of outliers and influential observations in the framework of a mixed linear model, prior to the quantitative trait locus (QTL) mapping analysis. We investigated the impact of outliers on QTL mapping for complex traits in a mouse BXD population, and observed that the dropping of outliers could provide the evidence of additional QTL and epistatic loci affecting the 1 stBrain-OB and the 2ndBrain-OB in a cross of the abovementioned population. The results could also reveal a remarkable increase in estimating heritabilities of QTL in the absence of outliers. In addition, simulations were conducted to investigate the detection powers and false discovery rates (FDRs) of QTLs in the presence and absence of outliers. The results suggested that the presence of a small proportion of outliers could increase the FDR and hence decrease the detection power of QTLs. A drastic increase could be obtained in the estimates of standard errors for position, additive and additivex environment interaction effects of QTLs in the presence of outliers. 相似文献
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Qun Liu Daqing Jiang Tasawar Hayat Ahmed Alsaedi 《Journal of The Franklin Institute》2019,356(13):7466-7485
In this paper, we investigate the threshold dynamics of a stochastic delayed SIS epidemic model with vaccination and double diseases which make the research more difficult. We establish sufficient conditions for extinction and persistence in the mean of the two diseases. We also obtain the threshold between persistence in the mean and extinction of the stochastic system. It is shown that: (i) time delay and environmental white noise have important effects on the persistence and extinction of the two diseases; (ii) the two diseases can coexist under certain conditions. Finally, some numerical simulations are provided to demonstrate the analytical results. 相似文献
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Ting Cui Feng Ding Xiangli Li Tasawar Hayat 《Journal of The Franklin Institute》2019,356(10):5485-5502
This paper focuses on the joint parameter and state estimation issue for observer canonical state-space systems with white noises in state equations and moving average noises in output equations. By means of the Kalman filtering and the gradient search, we derive a Kalman filtering based extended stochastic gradient algorithm. For purpose of achieving the higher parameter estimation accuracy, a Kalman filtering based multi-innovation extended stochastic gradient algorithm is proposed on the basis of the multi-innovation identification theory. Finally, the effectiveness of the proposed algorithms is validated through a numerical example. 相似文献
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Hui Jin Hayat Hokayem Sasha Wang Xin Wei 《International Journal of Science and Mathematics Education》2016,14(6):1037-1057
As China and the United States become the top two carbon emitters in the world, it is crucial for citizens in both countries to construct a sophisticated understanding of energy consumption issues. This interview study examines how U.S. and Chinese students compare in explaining and arguing about two critical energy consumption issues: burning fossil fuels and using electricity. In particular, we focused on using scientific knowledge to explain and argue about these issues. Based on relevant literature and our previous research, we developed a model to guide separate assessment and evaluation of students’ argumentation and explanation. We conducted clinical interviews with 40 biology majors, including 20 U.S. students and 20 Chinese students. This study generated several important findings. First, Chinese students tended to be less consistent across explanations and argumentation, and their levels of argumentation were lower than their levels of explanation. Second, in comparison to their Chinese counterparts, U.S. students provided more scientific arguments but many fewer scientific explanations. Finally, although all participants were college students and had completed at least one introductory level science course before the interviews, some of their explanations and arguments were based on informal ideas rather than matter and energy. We discuss the possible interpretations of these findings and their implications for teaching and learning of scientific explanation and argumentation in both countries. 相似文献
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Khizar Hayat Naeem Ali Al-Shukaili Khalid Sultan 《Education and Information Technologies》2017,22(4):1553-1569
The success of university-level education depends on the quality of underlying school education and any deficiency therein may be detrimental to a student’s career. This may be more glaring with Computer Science education, given its mercurial nature. In the developing countries, the Computer Science school curricula are usually stuffed with obsolete, unnecessary and dry contents. The problem is multiplied by the lack of qualified school teachers and separate media of instruction at the school and the university. In this paper we are focusing on the computer Science pedagogy at schools, with a possibility of introducing approaches, like Alice. The latter may on one hand be appealing to both the students and teachers and on the other hand may require a lot less training. With that in view, an experiment was designed to teach Alice, to sampled K-12 students, and study the ensued effects. The outcomes were realized in two ways. One, the attendees were required to furnish a small project/task in order to judge their understanding of Alice. Two, the students were surveyed for their views on Alice and possible inclusion of such approaches in their course. Given the brief contact time, the results were found to be promising as most of the respondents were in favor of a change in the approach Computer Science teaching. The tasks were well received by the respondents and most of them carried out the tasks assigned to them, enthusiastically. English language Comprehension was the single largest problem and that’s why the students demonstrated reluctance in adding dialogues on part of the characters. As far as the responses to the questionnaire were concerned, an overwhelming majority had a favorable opinion of the approach. They found it easy to use, understand, comprehend and considered it useful in initiating a novice to programming. They even rated it superior to their current syllabus. Some questions were chosen from the futuristic point of view and the responses were more than expected as the students felt motivated towards studying IT after coming across Alice. The only thing the respondents insisted was the inclusion Arabic language support in the future versions of Alice. 相似文献
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Yihong Zhou Yanjiao Wang Fengying Ma Feng Ding Tasawar Hayat 《Journal of The Franklin Institute》2021,358(4):2576-2595
This paper focuses on the parameter estimation for radial basis function-based state-dependent autoregressive models with moving average noises (RBF-ARMA models). An extended projection algorithm is derived based on the negative gradient search. In order to reduce the sensitivity of the algorithm to noise and reduce the fluctuations of the parameter estimation errors, a modified extended stochastic gradient algorithm is proposed. By introducing a moving data window, a modified moving data window-based extended stochastic gradient algorithm is further developed to improve the parameter estimation accuracy. The simulation results show that the proposed algorithms can effectively estimate the parameters of the RBF-ARMA models. 相似文献