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61.
Despite active research and significant progress in the last three decades on control of human eye movements, it remains challenging issue due to its applications in prosthetic eyes and robotics. Till now, no considerable investigation of this subject is presented in the interdisciplinary sciences. The goal of this paper is to present a distinguished survey of existing literature on the intelligent control of the human eye movements system applied in a huggable pet-type robot as a biomechatronic system.In this study, the basic knowledge of human eye movements control is explained to show how the neural networks in the brainstem control the human eye movements. The geometry and model of human eye movements system are investigated and this system is considered as a nonlinear control system. The specified model may only be an academic exercise. It can have scientific importance in understanding of the human movement system in general. Also, it can be useful for robotics.Intelligent methods such as artificial neural networks and fuzzy neural networks are proposed to control the human eye movements and numerical simulations are presented. It is discussed that the intelligent controls applied to control of human eye movements system are emulated from the neural controls in biological system.  相似文献   
62.
Discussions of the quality of learning in university education often focus on curricula. Less attention is paid to the role of student–staff interactions. In a context in which a host of factors place pressure on the opportunities for students and staff to interact, it is important to use empirical insights to inform decisions about how to optimise learning. This paper uses data from a large survey of students and teaching staff in Australia to suggest that students and staff should be regarded as allies in learning. It investigates student reports to suggest that frequent interactions with those who teach them lead to higher levels of student engagement and satisfaction and lower attrition rates. The advantages do not only flow in one direction. Teaching staff gain insights into students' learning experiences, providing them with clues to better target their teaching.  相似文献   
63.
The purpose of the paper is to explore Students' perception of university teaching behaviours in Pakistan. Three hundred and fifty students from the six public sector Pakistani universities returned questionnaires. Assessment framework, learning activities and instructional strategies emerged from factor analysis as common factors. Students' views on five conceptual variables were also analysed: instructional design, active teaching, learning activities, questioning styles; and assessment framework. University teaching in Pakistan was found to be driven by assessment. This is a matter of concern for all stake holders, including the administration of the universities, teachers, students and the Higher Education Commission. A teaching behaviour paradigm shift is required, switching from knowledge-oriented teaching behaviour focused on successful passage through assessment, to teaching behaviour focused upon the development of transferable skills demanded by external markets.  相似文献   
64.
Although Richard Rorty's controversial thought has been the subject of many works, there has not been much discussion about his approach to cultural difference. The purpose of this article is to examine how Rorty sees cultural differences philosophically and how he deals with them politically. For him, rationality, morality and even the scope of moral responsibility towards others are defined in terms of solidarity with a particular community and ‘ethnocentrism’, rather than in terms of a universal and metaphysically derived set of criteria. It can be argued that since language, language games and values are mainly components of culture, the latter is one of the most significant communities with which Rorty is concerned, though he is not explicit about it. Nevertheless, Rorty does not think that the moral and philosophical significance of communities, particularly cultural communities, should be reflected in politics. The main argument of the article is that there is an unresolved tension in Rorty's thought between philosophical, moral and emotional attribution of significance to communities and arguably cultural communities, and a disregard for them in the political sphere. This paves the way for outlining an approach to cultural difference that is more just and even more in harmony with Rorty's own philosophy.  相似文献   
65.
Forty-six Streptomyces strains were isolated from paintings and stone surfaces from Tell Basta and Tanis tombs (80 km south-east Cairo, Egypt). Eight of these strains were selected to determine their sensitivity against 13 antibiotics. In general, high levels of resistance could be observed. Gentamycin, spiramycin and doxycycline were the most effective antibiotics against the majority of strains under study. Due to the observed antibiotic resistances, gamma irradiation was studied as a possible alternative to inhibit microbial growth. Isolated bacteria were exposed to different doses of gamma irradiation (5, 10, 15, 20 and 25 kGy). The growth of all Streptomyces isolates except S. canarius was completely inhibited at 25 kGy. The applied doses of gamma irradiation did not cause any observable alterations or colour changes to pigments and binding media (arabic gum, animal glue and egg-yolk) used in the paintings.  相似文献   
66.
This paper studies the problems of stability and H∞ model reference tracking performance for a class of asynchronous switched nonlinear systems with uncertain input delay. First, it is assumed switched controller and corresponding piecewise Lyapunov function are unknown but the derivative of piecewise Lyapunov function has a condition; this condition implies that the nominal system (system without input delay and disturbance) is exponentially stable by any switched controller which satisfies this condition. With this assumption, a proper Lyapunov–Krasovskii functional is constructed. By employing this new functional and average dwell time technique, the delay-dependent input-to-state stability criteria are derived under a certain delay bound; in addition, a mechanism which finds the upper bound of input delay is proposed. Finally, a kind of state feedback control law which fulfils condition of aforesaid piecewise Lyapunov function is introduced to guarantee the input-to-state stability and H∞ model reference tracking performance. Simulation examples are presented to demonstrate the efficacy of results.  相似文献   
67.
Mismatched uncertainty and chattering appear as two challenges in sliding mode control. To overcome the problem of mismatched uncertainty, multiple sliding surfaces with virtual inputs are proposed. Accordingly, we have proposed two new methods based on designed neural observer: sliding mode control (SMC) and dynamic sliding mode control (DSMC) methods. Although, the proposed SMC can significantly cope with the mismatched uncertainties, but it suffers from chattering phenomenon. The chattering problem can be removed in DSMC, because an integrator is placed before the system. This results in increased number of the system states. This new state can be identified with the proposed neural observer. Note that in both proposed approaches, the robust performance (invariance property) of system is reserved, even in the presence of mismatch uncertainties. Then, to have a valid comparison the proposed DSMC is also designed using loop transfer recovery observer (LTRO). This comparison shows the good performance of the DSMC based neural networks. Moreover, the upper bound of uncertainties is not used in SMC and DSMC controllers and also in the neural observer and LTRO, which is important in practical implementation. Finally, comparing the equations, one can see the simplicity of DSMC in concept and also in realization.  相似文献   
68.
This paper deals with the leader-following consensus problem of multi-agent systems with the consideration that each agent can only transmit its position state to the neighbors at irregular discrete sampling times. In the proposed algorithm, a continuous-discrete time observer is designed for the continuous estimation of both position and velocity from the discrete position information of the neighbors. These estimated states are then used for designing a continuous control law which solves the leader-following consensus problem. Moreover, the dynamics of the leader is not fixed and can be controlled through an external input. The stability analysis has been carried out by employing the Lyapunov approach which provides sufficient conditions to tune the parameters according to the maximum allowable sampling period. The developed algorithm has been simulated and then tested on an actual multi-robot system consisting of three differential drive wheeled robots. Both simulation and hardware results validate the effectiveness of the control algorithm.  相似文献   
69.
This study provides a glimpse into understanding the potential benefits as well as harm of playing video games from the perspective of six Malaysian secondary school students, aged 16-17 years old. The rationale of the study is to enable parents, educators, administrators and policy makers to develop a sound understanding on the impact of playing video games before making any judgment on the contemporary youth culture. Thus, further decision on the acceptance of video games as a new innovation in school or at home could be considered. Although this study is not very extensive, the findings suggest that playing video games contributes to cognitive, social, motivational and emotional development. However, potential harms do exist. Parents play an important role in guiding their children either directly or indirectly, as indicated by the respective students. Caution is advised in the interpretation of the study's findings as it is solely based on the perspectives of the students, as the first person's views. Nevertheless, each student has their very own perspective on the impact of video games on them.  相似文献   
70.
从十多年证券市场的发展历程来看,股权筹资处于主导地位,而债权筹资不足.近几年衍生金融工具筹资有了一些新的发展,如可转债、权证、资产支持证券等,为上市公司筹资提供了更多可供选择的筹资渠道体系.2000年以后股权筹资金额逐年下降,债权筹资逐年上升,资本结构逐步趋于合理.全流通后,上市公司的筹资市场环境将发生巨大的变化,企业的筹资成本与风险也会发生很大的变化,股权筹资稀释控制权的后果将会显现出来,负债筹资的优势也会更加明显.上市公司应充分利用不同筹资工具的优势和特色,降低企业的资金成本和筹资风险,优化资本结构.  相似文献   
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