University of Waterloo

About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.

Surface modification of nanozymes

Abstract: Nanoparticles and proteins are similar in a number of aspects, and using nanoparticles to mimic the catalytic function of enzymes is an interesting yet challenging task. Impressive developments have been made over the past two decades on this front. The term nanozyme was coined to refer to nanoparticlebased enzyme mimics. To date, many different types of nanozymes have been reported to catalyze a broad range of reactions for chemical, analytical, and biomedical applications. Since chemical reactions happen mainly on the surface of nanozymes, an interesting aspect for investigation is surface modification. In this review, we summarize three types of nanozyme materials catalyzing various reactions with a focus on their surface chemistry. For metal oxides, cerium oxide and iron oxide are discussed as they are the most extensively studied. Then, gold nanoparticles and graphene oxide are reviewed to represent metallic and carbon nanomaterials, respectively. Types of modifications include ions, small molecules, and polymers mainly by physisorption, while in a few cases, covalent modifications were also employed. The functional aspect of such modification is to improve catalytic activity, substrate specificity, and stability. Future perspectives of this field are speculated at the end of this review.

Evaluation Of The Grey-level Co-occurrence Matrix Method For Land-cover Classification Using Spot Imagery

Abstract: Absfruct-Nine cover types have been classified using a textural/ spectral approach. The texture analysis is based on the grey-level cooccurrence matrix method. Texture features are created from a SPOT near-infrared image using four texture indices, seven window sizes, and two quantization levels. A supervised classification based on the maximum-likelihood algorithm is applied to the three SPOT multispectral bands combined with each texture image individually and to the three bands combined with all four texture images. Classification accuracy is measured by Kappa coefficients calculated from confusion matrices. A factor analysis, based on principal components, is performed to evaluate the contribution to the classification accuracy of each variable involved in the creation of the texture features. The addition of texture features provides a significant improvement in the classification accuracy of each cover type when compared with the results obtained from the multispectral analysis alone. The window size accounts for 90% of the classification variability, 7% is explained by the statistics used as texture measures, and only 3% by the quantization level. There is a window size that optimizes the discrimination of each cover type.

Dynamic Controller Provisioning in Software Defined Networks

Abstract: Software Defined Networking (SDN) has emerged as a new paradigm that offers the programmability required to dynamically configure and control a network. A traditional SDN implementation relies on a logically centralized controller that runs the control plane. However, in a large-scale WAN deployment, this rudimentary centralized approach has several limitations related to performance and scalability. To address these issues, recent proposals have advocated deploying multiple controllers that work cooperatively to control a network. Nonetheless, this approach drags in an interesting problem, which we call the Dynamic Controller Provisioning Problem (DCPP). DCPP dynamically adapts the number of controllers and their locations with changing network conditions, in order to minimize flow setup time and communication overhead. In this paper, we propose a framework for deploying multiple controllers within an WAN. Our framework dynamically adjusts the number of active controllers and delegates each controller with a subset of Openflow switches according to network dynamics while ensuring minimal flow setup time and communication overhead. To this end, we formulate the optimal controller provisioning problem as an Integer Linear Program (ILP) and propose two heuristics to solve it. Simulation results show that our solution minimizes flow setup time while incurring very low communication overhead.

Coarse-graining spectral analysis: new method for studying heart rate variability

Abstract: Heart rate variability (HRV) spectra are typically analyzed for the components related to low- (less than 0.15 Hz) and high- (greater than 0.15 Hz) frequency variations. However, there are very-low...