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This paper proposes an adaptive scheme of designing sliding mode control (SMC) for affine class of multi-input multi-output (MIMO) nonlinear systems with uncertainty in the systems dynamics and control distribution gain. The proposed adaptive SMC does not require any a priori knowledge of the uncertainty bounds and therefore offers significant advantages over the non-adaptive schemes of SMC design. The closed loop stability conditions are derived based on Lyapunov theory. The effectiveness of the proposed approach is demonstrated via simulations considering an example of a two-link robot manipulator and has been found to be satisfactory. 相似文献
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Salmanzadeh A Kittur H Sano MB C Roberts P Schmelz EM Davalos RV 《Biomicrofluidics》2012,6(2):24104-2410413
Ovarian cancer is the leading cause of death from gynecological malignancies in women. The primary challenge is the detection of the cancer at an early stage, since this drastically increases the survival rate. In this study we investigated the dielectrophoretic responses of progressive stages of mouse ovarian surface epithelial (MOSE) cells, as well as mouse fibroblast and macrophage cell lines, utilizing contactless dielectrophoresis (cDEP). cDEP is a relatively new cell manipulation technique that has addressed some of the challenges of conventional dielectrophoretic methods. To evaluate our microfluidic device performance, we computationally studied the effects of altering various geometrical parameters, such as the size and arrangement of insulating structures, on dielectrophoretic and drag forces. We found that the trapping voltage of MOSE cells increases as the cells progress from a non-tumorigenic, benign cell to a tumorigenic, malignant phenotype. Additionally, all MOSE cells display unique behavior compared to fibroblasts and macrophages, representing normal and inflammatory cells found in the peritoneal fluid. Based on these findings, we predict that cDEP can be utilized for isolation of ovarian cancer cells from peritoneal fluid as an early cancer detection tool. 相似文献
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OBJECTIVE: The objective of this study was to document the psychosocial adjustment of young refugees during their adolescence and its association with the war-related trauma experienced by their family before migration. METHOD: Data were collected on 57 young Khmer resettled in Montreal and followed from early to late adolescence. The associations between premigratory exposure to political violence and postmigratory mental health and social adjustment were estimated for early, mid-, and late adolescence. RESULTS: The associations between premigratory exposure to political violence and postmigratory psychosocial adjustment fluctuated over the adolescence period. Overall, the adolescents whose families were more highly exposed to political violence tended to report a more positive social adjustment and less mental health symptoms than those less exposed. CONCLUSION: The high expectations of Cambodian parents towards their children and the preservation of traditional values despite the Khmer rouge attempts to eradicate them might contribute to explain the paradoxical association between the families' exposure to political violence and the adolescents' psychosocial adjustment in the host country. Although children and adult refugees seen in clinical setting are reminders of the negative effects of adversity, resilience should be more systematically explored in community samples to further our understanding of the long-term effects of trauma. 相似文献
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Navid Vafamand Mohammad Hassan Asemani Alireza Khayatian 《Journal of The Franklin Institute》2017,354(14):5854-5876
In this paper, a novel technique for Takagi–Sugeno (TS) model-based robust L1 controller design of nonlinear systems is proposed. Two synthesis methods based on quadratic and non-quadratic Lyapunov functions are considered. To design the robust stabilizing controller, a new approach for deriving sufficient conditions associated with the L1 performance criterion in terms of strict linear matrix inequality is proposed. This novel technique results in less pre-chosen scalar design variables and calculation burden. Furthermore, deriving the controller synthesis conditions via a non-quadratic Lyapunov function (NQLF) relaxes the obtained conditions. Therefore, the proposed approaches not only efficiently minimize the effect of persistent bounded disturbance, but also are applicable for wider classes of TS systems. Furthermore, some new lemmas are proposed to facilitate strict LMI formulation and to provide more degrees of freedom. Finally, several numerical and practical examples are presented to show the merits of this paper. 相似文献
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Ali Bikmoradi Mats Brommels Alireza Shoghli Davoud Khorasani Zavareh Italo Masiello 《Higher Education》2009,57(4):417-427
In Iran, restructuring of medical education and the health care delivery system in 1985 resulted in a rapid shift from elite
to mass education, ultimately leading to an increase in the number of medical schools, faculties, and programs and as well
as some complications. This study aimed to investigate views on academic culture, values, and routines held by faculty members.
A nation-wide survey conducted in six public medical schools in Iran. The research findings show weak organizational culture
and values, together with routine behaviors sensed as a negative and low satisfaction with academic leadership. The research
evidence suggests bureaucracy, politicization, conservativeness, and centralization as common features of medical schools
in Iran and also suggests suitable supervisory skills to tackle the tension between governmental management and academic leadership
with cultural changes, the creation of new values, and adoption more efficient routines. 相似文献
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Problematic placement: pathways pre-service teachers’ perspectives on their infant/toddler placement 总被引：1，自引：0，他引：1
Liz Rouse Anne-Marie Morrissey Mohammadali Rahimi 《Early Years: An International Journal of Research and Development》2012,32(1):87-98
The inclusion of an infant/toddler placement in a ‘pathways’ early childhood teaching degree, where students already have qualifications and experience in working with young children, can be problematic. This pilot study investigated student teachers’ views on their infant/toddler (birth-to-two-years) placement. Sixty-six students completing their early childhood education degree at an Australian university responded to a survey seeking their perspectives on the effectiveness of the placement in developing teacher confidence, knowledge and skills, and the quality of the supervision they received. The participants had entered their degree with a two-year Diploma of Children’s Services. Responses indicated significant dissatisfaction with the quality of supervision, the absence of teacher-mentors, and the lack of opportunities to practise new approaches. Participants commented that they ‘already knew’ how to work with this age group, and that they aspired to work with older children. The results align with other findings on factors associated with positive placements, and raise questions about the effectiveness of the infant/toddler placement in its current form. 相似文献