832 research outputs found
Dense Voxel 3D Reconstruction Using a Monocular Event Camera
Event cameras are sensors inspired by biological systems that specialize in
capturing changes in brightness. These emerging cameras offer many advantages
over conventional frame-based cameras, including high dynamic range, high frame
rates, and extremely low power consumption. Due to these advantages, event
cameras have increasingly been adapted in various fields, such as frame
interpolation, semantic segmentation, odometry, and SLAM. However, their
application in 3D reconstruction for VR applications is underexplored. Previous
methods in this field mainly focused on 3D reconstruction through depth map
estimation. Methods that produce dense 3D reconstruction generally require
multiple cameras, while methods that utilize a single event camera can only
produce a semi-dense result. Other single-camera methods that can produce dense
3D reconstruction rely on creating a pipeline that either incorporates the
aforementioned methods or other existing Structure from Motion (SfM) or
Multi-view Stereo (MVS) methods. In this paper, we propose a novel approach for
solving dense 3D reconstruction using only a single event camera. To the best
of our knowledge, our work is the first attempt in this regard. Our preliminary
results demonstrate that the proposed method can produce visually
distinguishable dense 3D reconstructions directly without requiring pipelines
like those used by existing methods. Additionally, we have created a synthetic
dataset with object scans using an event camera simulator. This
dataset will help accelerate other relevant research in this field
Design and Development of an E-Learning Management System
The trend of e-learning technologies is expanding fast. Web-based learning environments are becoming very common in the higher education institutions. Nowadays e-learning management systems are very popular. Many universities throughout the world deliver educational programs via the Internet. Developments of e-learning systems are generating great impact in the field of education services to improve the teaching and learning process, and overcome geographical displace. In recent years, various kinds of Internet technologies have become available for developers to implement such e-learning system that provide an e-learning gateway on the Internet. The rapid advancements in information and communication technologies, especially the networking and multimedia, have led to the development of many advanced e-learning systems these days. A user-friendly interface and a sophisticated data model are the essential design consideration to make the e-learning system easy-to-use for the instructors and learners. The need for such architecture is critical for designing the system and standards development. The system is developed under Computer Supported Cooperative Work framework and web portal technology. The system integrates all the critical and valuable communication tools that effectively improve the collaboration in an e-learning environment
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Multi-Scale Glycemic Variability: A Link to Gray Matter Atrophy and Cognitive Decline in Type 2 Diabetes
Objective: Type 2 diabetes mellitus (DM) accelerates brain aging and cognitive decline. Complex interactions between hyperglycemia, glycemic variability and brain aging remain unresolved. This study investigated the relationship between glycemic variability at multiple time scales, brain volumes and cognition in type 2 DM. Research Design and Methods Forty-three older adults with and 26 without type 2 DM completed 72-hour continuous glucose monitoring, cognitive tests and anatomical MRI. We described a new analysis of continuous glucose monitoring, termed Multi-Scale glycemic variability (Multi-Scale GV), to examine glycemic variability at multiple time scales. Specifically, Ensemble Empirical Mode Decomposition was used to identify five unique ultradian glycemic variability cycles (GVC1–5) that modulate serum glucose with periods ranging from 0.5–12 hrs. Results: Type 2 DM subjects demonstrated greater variability in GVC3–5 (period 2.0–12 hrs) than controls (P<0.0001), during the day as well as during the night. Multi-Scale GV was related to conventional markers of glycemic variability (e.g. standard deviation and mean glycemic excursions), but demonstrated greater sensitivity and specificity to conventional markers, and was associated with worse long-term glycemic control (e.g. fasting glucose and HbA1c). Across all subjects, those with greater glycemic variability within higher frequency cycles (GVC1–3; 0.5–2.0 hrs) had less gray matter within the limbic system and temporo-parietal lobes (e.g. cingulum, insular, hippocampus), and exhibited worse cognitive performance. Specifically within those with type 2 DM, greater glycemic variability in GVC2–3 was associated with worse learning and memory scores. Greater variability in GVC5 was associated with longer DM duration and more depression. These relationships were independent of HbA1c and hypoglycemic episodes. Conclusions: Type 2 DM is associated with dysregulation of glycemic variability over multiple scales of time. These time-scale-dependent glycemic fluctuations might contribute to brain atrophy and cognitive outcomes within this vulnerable population
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A Nonlinear Dynamic Approach Reveals a Long-Term Stroke Effect on Cerebral Blood Flow Regulation at Multiple Time Scales
Cerebral autoregulation (CA) is an important vascular control mechanism responsible for relatively stable cerebral blood flow despite changes of systemic blood pressure (BP). Impaired CA may leave brain tissue unprotected against potentially harmful effects of BP fluctuations. It is generally accepted that CA is less effective or even inactive at frequencies >∼0.1 Hz. Without any physiological foundation, this concept is based on studies that quantified the coupling between BP and cerebral blood flow velocity (BFV) using transfer function analysis. This traditional analysis assumes stationary oscillations with constant amplitude and period, and may be unreliable or even invalid for analysis of nonstationary BP and BFV signals. In this study we propose a novel computational tool for CA assessment that is based on nonlinear dynamic theory without the assumption of stationary signals. Using this method, we studied BP and BFV recordings collected from 39 patients with chronic ischemic infarctions and 40 age-matched non-stroke subjects during baseline resting conditions. The active CA function in non-stroke subjects was associated with an advanced phase in BFV oscillations compared to BP oscillations at frequencies from ∼0.02 to 0.38 Hz. The phase shift was reduced in stroke patients even at > = 6 months after stroke, and the reduction was consistent at all tested frequencies and in both stroke and non-stroke hemispheres. These results provide strong evidence that CA may be active in a much wider frequency region than previously believed and that the altered multiscale CA in different vascular territories following stroke may have important clinical implications for post-stroke recovery. Moreover, the stroke effects on multiscale cerebral blood flow regulation could not be detected by transfer function analysis, suggesting that nonlinear approaches without the assumption of stationarity are more sensitive for the assessment of the coupling of nonstationary physiological signals
Generic Supply Chain Management System
Supply chain management refers to all the management functions related to the flow of materials from the company’s direct suppliers to its direct customers. In this paper, we will propose a generic supply chain management system, and describe how the system works in terms of information exchange, workflow coordination and flexible logistic route. We will introduce two data models, which are called PDM and WfMS, and explain how to classify the proposed system into them. And then, we will further describe how the back-end three-layered architecture stores the dynamic data type into the database
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