Stabilization of Discrete-Time Planar Switched Linear Systems with Impulse

We study the stabilization problem of discrete-time planar switched linear systems with impulse. When all subsystems are controllable, based on an explicit estimation on the state transition matrix, we establish a sufficient condition such that the switched impulsive system is stabilizable under arbitrary switching signal with given switching frequency. When there exists at least one uncontrollable subsystem, a sufficient condition is also given to guarantee the stabilization of the switched impulsive system under appropriate switching signal

Turning Disruption into Growth Opportunity: The Red Team Strategy

The purpose of this paper is to propose a broadened and integrated red team strategy with concrete steps to help companies better deal with the disruptive forces prevalent in our world today and turn disruptions into growth. We suggest four key steps to help companies implement the red team strategy: 1) create a red team culture and encourage diverse perspectives, 2) establish an independent red team to overcome organizational inertia, 3) use the red team to embrace disruption and growth opportunities, and 4) take a milestone approach to red team execution and resource allocation. Our red team strategy provides concrete steps to help companies in their efforts to adapt to and capitalize on disruptive forces

Synergy in Additive Manufacturing and Machining of Complex Design Topologies

Additive manufacturing (AM) enables freedom of design, part complexity and customization with minimal added cost, light weighting, design for function, and part consolidation. It is gaining increasing interests in the fields of biomedical, aerospace, automotive, tooling, and heat exchange systems where small batch productions of customized parts with high value are usually in demand. AM, in general, is considered to have great potential in complementing conventional manufacturing methods. Functional parts with high strength to weight ratio generated using structural topology optimization can be eventually realized by AM. Limitations of AM parts related to surface finish and dimensional accuracy are likely to be overcome by post-machining of critical features and surfaces in order to achieve specific tolerance and surface quality. To minimize trial and error efforts, AM and post-machining simulations are essential for effective planning of the synergized processes. The goal of this study is to propose a process workflow which can be used as a guideline for successful production of complex parts manufactured via AM, particularly laser powder bed fusion (LPBF), and post-processed via CNC (computer numerical control) machining. The workflow is deployed and iterated through a case study of manufacturing a surgical navigation tracker, where the holistic manufacturing process involves digital design utilizing structural topology optimization, AM simulation, machining planning, fabrication, and validation

Role of hypoxia-inducible factor-1α in preconditioning-induced protection of retinal ganglion cells in glaucoma

PURPOSE: We recently demonstrated in a mouse model of glaucoma that endogenous epigenetic mechanisms can be activated by a repetitive hypoxic preconditioning (RHP) stimulus to provide robust retinal ganglion cell (RGC) protection. Although we also provided evidence that RHP prevents or delays the apoptotic demise of the RGC soma, the mechanisms responsible for signaling this epigenetic response, as well as the effectors of the glaucoma-tolerant phenotype at the somatic and axonal levels, remain unidentified. In the present study, we used conditional mutant mice lacking hypoxia-inducible factor-1α (HIF-1α) in RGCs (HIF-1α RGC-knockout [KO] mice) to test the hypothesis that RHP-mediated activation of this transcription factor in these cells protects them from glaucomatous injury. METHODS: Adult HIF-1α RGC-KO mice, generated by mating floxed HIF-1α mice with math5-Cre mice, were used. Experimental glaucoma was induced unilaterally in the HIF-1α RGC-KO mice and matched wild-types by elevating the intraocular pressure to 16–20 mmHg for 3 consecutive weeks, secondary to episcleral vein ligation. Mice of each genotype were randomized to either an RHP protocol (six total exposures to systemic hypoxia [11% oxygen], interspersed over a 2-week period, completed 3 days before ligation surgery) or to an untreated group. RGC soma and axon injury was quantified with Neuronal Nuclei (NeuN) immunohistochemistry in retinal flat mounts and SMI32 immunohistochemistry in cross sections of the post-laminar optic nerve, respectively. RESULTS: HIF-1α RGC-KO mice exhibited normal retinal function and morphology, and crosses of math5-Cre mice with floxed ROSA26 reporter mice confirmed Cre recombinase activity was confined to the RGC axons and soma. Untreated wild-type mice exhibited a 30±2% loss of RGC soma and a 31±3% loss of RGC axons after 3 weeks of intraocular hypertension (both p<0.05 versus fellow eye). The 90% and 81% improvement in soma and axon survival, respectively, observed in the wild-type mice treated with RHP (both p<0.05 versus the glaucoma eye in the untreated mice) was still observed to a near identical extent in the RHP-treated HIF-1α RGC-KO mice. RHP had no effect on the magnitude of intraocular pressure elevation in either the KO or wild-type groups, indicating that protection was realized in both genotypes in the face of ongoing intraocular hypertension. CONCLUSIONS: These findings indicate that the robust, glaucomatous protection of the RGC soma and axons induced by RHP does not require HIF-1α-mediated transcription of survival genes and other adaptive responses within the RGCs themselves. Rather, we infer that RGC survival is augmented secondary to the activation of other hypoxia-sensitive transcription factors in RGCs and/or the action of diffusible HIF-1α target gene proteins released from neighboring retinal cells. Ideally, the involvement of such autocrine- and/or paracrine-based mechanisms would be confirmed in future studies, but distinct components of the integrated, pleiotropic, and multicellular basis of this endogenous epigenetic response may prove difficult to demonstrate experimentally, as we found in the present study

A simulation data-driven design approach for rapid product optimization

Traditional design optimization is an iterative process of design, simulation, and redesign, which requires extensive calculations and analysis. The designer needs to adjust and evaluate the design parameters manually and continually based on the simulation results until a satisfactory design is obtained. However, the expensive computational costs and large resource consumption of complex products hinder the wide application of simulation in industry. It is not an easy task to search the optimal design solution intelligently and efficiently. Therefore, a simulation data-driven design approach which combines dynamic simulation data mining and design optimization is proposed to achieve this purpose in this study. The dynamic simulation data mining algorithm—on-line sequential extreme learning machine with adaptive weights (WadaptiveOS-ELM)—is adopted to train the dynamic prediction model to effectively evaluate the merits of new design solutions in the optimization process. Meanwhile, the prediction model is updated incrementally by combining new “good” data set to reduce the modeling cost and improve the prediction accuracy. Furthermore, the improved heuristic optimization algorithm—adaptive and weighted center particle swarm optimization (AWCPSO)—is introduced to guide the design change direction intelligently to improve the search efficiency. In this way, the optimal design solution can be searched automatically with less actual simulation iterations and higher optimization efficiency, and thus supporting the rapid product optimization effectively. The experimental results demonstrate the feasibility and effectiveness of the proposed approach

Im/possible Lives: Gender, Class, Self-Fashioning, and Affinal Solidarity in Modern South Asia

Drawing on ethnographic research and employing a micro-historical approach that recognizes not only the transnational but also the culturally specific manifestations of modernity, this article centers on the efforts of a young woman to negotiate shifting and conflicting discourses about what a good life might consist of for a highly educated and high caste Hindu woman living at the margins of a nonetheless globalized world. Newly imaginable worlds in contemporary Mithila,South Asia, structure feeling and action in particularly gendered and classed ways, even as the capacity of individuals to actualize those worlds and the “modern” selves envisioned within them are constrained by both overt and subtle means. In the context of shifting cultural anchors, new practices of silence, literacy, and even behaviors interpreted as “mental illness” may become tactics in an individual’s negotiation of conflicting self-representations. The confluence of forces at play in contemporary Mithila, moreover, is creating new structures of feeling that may begin to reverse long-standing locally held assumptions about strong solidarities between natal families and daughters, on the one hand, and weak solidarities between affinal families and new daughters-in-law, on the other

Route Identification Method for On-Ramp Traffic at Adjacent Intersections of Expressway Entrance

To determine the control strategy at intersections adjacent to the expressway on-ramp, a route identification method based on empirical mode decomposition (EMD) and dynamic time warping (DTW) is established. First, the de-noise function of EMD method is applied to eliminate disturbances and extract features and trends of traffic data. Then, DTW is used to measure the similarity of traffic volume time series between intersection approaches and expressway on-ramp. Next, a three-dimensional feature vector is built for every intersection approach traffic flow, including DTW distance, space distance between on-ramp and intersection approach, and intersection traffic volume. Fuzzy C-means clustering method is employed to cluster intersection approaches into classifications and identify critical routes carrying the most traffic to the on-ramp. The traffic data are collected by inductive loops at Xujiahui on-ramp of North and South Viaduct Expressway and surrounding intersections in Shanghai, China. The result shows that the proposed method can achieve route classification among intersections for different time periods in one day, and the clustering result is significantly influenced by three dimensions of traffic flow feature vector. As an illustrative example, micro-simulation models are built with different control strategies. The simulation shows that the coordinated control of critical routes identified by the proposed method has a better performance than coordinated control of arterial roads. Conclusions demonstrated that the proposed route identification method could provide a theoretical basis for the coordinated control of traffic signals among intersections and on-ramp. Document type: Articl

Characteristics of Local Modulation Beam Propagating through Spatial Filter System

As local defects may significantly harm beam quality and affect safe operation, a systematic analysis of the ability of a spatial filter to alleviate these adverse effects is required. Thus, the evolutional characteristics of a beam modulated by a local defect propagating through a spatial filter system at an image reply plane and a downstream plane are analyzed in detail. Modulation stripes appear at the image reply plane; these are caused by the pinhole cutoff effect. The modulation degree increases with increasing defect size. The maximum intensification factor can reach 3.2 under certain conditions. Thus, the defect size should be restricted to a reasonable size for safe operation with a specified pinhole size. Moreover, a maximal value appears at the downstream plane, and the intensity enhances with increasing defect size. To ensure beam quality, the maximum allowable defect size and angle of the spatial filter should meet special constraints. The maximum allowable defect size is calculated based on practical configuration parameters