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排序方式: 共有101条查询结果,搜索用时 15 毫秒
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Aldo Jonathan Muñoz-Vázquez Vicente Parra-Vega Anand Sánchez-Orta Oscar Martínez-Fuentes 《Journal of The Franklin Institute》2021,358(9):4793-4806
Disturbance observer-based control allows to compensate unknown inputs, however, in most cases, requiring their integer-order differentiability. In this paper, a novel disturbance observer-based state feedback controller is proposed to compensate a more general class of fractional-, but not necessarily integer-order, differentiable unknown inputs. The proposed fractional PI-like structure yields precise conditions for feedback gain tuning. Remarkably, the resulting controller rejects non-differentiable disturbances with a smooth controller, guaranteeing robustness, an outstanding features for tracking tasks, under a prescribed practical stability regimen. A comparison to a fractional sliding mode observer is conducted via simulations to highlight the reliability of the proposed scheme. 相似文献
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Transportation agencies spend millions of dollars annually to repair civil transportation infrastructure including pavements, earth structures and approach slabs distressed by soft compressible soils and expansive soils. Several research studies performed at the University of Texas at Arlington (UTA) focused on stabilizing these problematic soils so that they will provide better and more stable support to the transportation infrastructure. This paper focuses on a summary of two major distresses and mechanisms, and remedial measures for addressing these distress problems. A combined lime-cement stabilization method is fully evaluated in providing better support of pavement infrastructure, and these results are described here. Another major transportation infrastructure problem involving bridge approach slabs requires different treatment methods, and these results are briefly described. As a part of the recently completed research study assessments, both shallow and deep soil treatment methods for stabilizing soils are fully evaluated for their effectiveness in arresting the distress posed to the pavements and bridge approach slabs. These results along with a few future research needs are presented in this paper. 相似文献
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Dimple Anand Sabari Das Sumit Ray Seema Bhargava Lalit Mohan Srivastava 《Indian journal of clinical biochemistry : IJCB》2014,29(1):93-96
Sepsis suffers from lack of specific clinical symptoms which contribute to one of the major causes of mortality. In the present study, our aim was to evaluate the role of a recent biomarker Procalcitonin (PCT) in predicting organ dysfunction. 71 patients admitted with sepsis were included in the study. PCT levels were measured at 0, 24, 72 h and 7th day and sequential organ failure assessment score (SOFA) scores were calculated. PCT levels significantly decreased (p < 0.001) in 89.3 % of surviving patients, whereas, in 60 % non surviving patients the PCT level increased significantly (p < 0.001). A significant positive correlation between PCT and SOFA score was observed in survivors at each hour. These observations indicate that PCT concentration is significantly associated with severity of multi organ dysfunction and also helps in determining the prognosis of septic patients. 相似文献
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Holger Gaertner Sebastian Wurster Hans Anand Pant 《School Effectiveness & School Improvement》2013,24(4):489-508
This study uses a school-level longitudinal control-group design to examine how teachers and principals of inspected versus uninspected schools perceive school improvement at their schools. During the phasing in of school inspections in the states of Berlin and Brandenburg (Germany), both inspected and uninspected schools were surveyed with respect to school improvement activities over a 1-year period. The main finding is that principals’ and teachers’ perceptions of school quality were highly stable, irrespective of the introduction of school inspections. The results show school inspections had a comparatively low impact on the aspects of school quality measured here. 相似文献
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An ordering system for a global information network is necessary in order to enable the user to retrieve the particular information he is looking for. Classification has been one of the methods of ordering. The principle of traditional classification has been based on the idea of partitioning the universe of knowledge in mutually exclusive classes, i.e. subjects. A particular topic is defined by narrower classification within a class following the principle of ‘genusspecies’ relationship. Ranganathan's system of faceted classification has only replaced the classification of terms into subjects and sub-subjects by classification of terms into five ambiguous categories. Taube's system of coordinate indexing gives full freedom to the user to combine any number of terms of his choice. To be effective for social sciences such a system has to overcome some difficult problems of semantics. The system MANIS described here maintains the traditional classification and yet allows the user to combine terms of his choice, where the choice is restricted to the terms belonging to the system of traditional classification. 相似文献