scholarly journals Generalized Structure Preserving Preconditioners for Frame-Based Image Deblurring

Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 468 ◽  
Author(s):  
Davide Bianchi ◽  
Alessandro Buccini
Keyword(s):  
Coefficient Matrix ◽  
Image Deblurring ◽  
Regularization Methods ◽  
Wavelet Domain ◽  
Iterative Regularization ◽  
True Solution ◽  
Structure Preserving ◽  
Imaging Model ◽  
Key Features

We are interested in fast and stable iterative regularization methods for image deblurring problems with space invariant blur. The associated coefficient matrix has a Block Toeplitz Toeplitz Blocks (BTTB) like structure plus a small rank correction depending on the boundary conditions imposed on the imaging model. In the literature, several strategies have been proposed in the attempt to define proper preconditioner for iterative regularization methods that involve such linear systems. Usually, the preconditioner is chosen to be a Block Circulant with Circulant Blocks (BCCB) matrix because it can efficiently exploit Fast Fourier Transform (FFT) for any computation, including the (pseudo-)inversion. Nevertheless, for ill-conditioned problems, it is well known that BCCB preconditioners cannot provide a strong clustering of the eigenvalues. Moreover, in order to get an effective preconditioner, it is crucial to preserve the structure of the coefficient matrix. On the other hand, thresholding iterative methods have been recently successfully applied to image deblurring problems, exploiting the sparsity of the image in a proper wavelet domain. Motivated by the results of recent papers, the main novelty of this work is combining nonstationary structure preserving preconditioners with general regularizing operators which hold in their kernel the key features of the true solution that we wish to preserve. Several numerical experiments shows the performances of our methods in terms of quality of the restorations.

scholarly journals A Taxonomic Review of Patient Complaints in Adult Hospital Medicine

2021 ◽  
Vol 8 ◽  
pp. 237437352110073
Author(s):  
Richard M Elias ◽  
Karen M Fischer ◽  
Mustaqeem A Siddiqui ◽  
Trevor Coons ◽  
Cindy A Meyerhofer ◽  
...  
Keyword(s):  
Hospital Admissions ◽  
Hospital Medicine ◽  
Patient Complaints ◽  
Period Data ◽  
The Mean ◽  
Key Features ◽  
Person Characteristics ◽  
The Relationship ◽  
Adult Hospital

Previous studies show that patient complaints can identify gaps in quality of care, but it is difficult to identify trends without categorization. We conducted a review of complaints relating to admissions on hospital internal medicine (HIM) services over a 26-month period. Data were collected on person characteristics and key features of the complaint. The complaints were also categorized into a previously published taxonomy. Seventy-six unsolicited complaints were identified, (3.5 per 1000 hospital admissions). Complaints were more likely on resident services. The mean duration between encounter and complaint was 18 days, and it took an average of 12 days to resolve the complaint. Most patients (59%) had a complaint in the Relationship domain. Thirty-nine percent of complaints mentioned a specific clinician. When a clinician was mentioned, complaints regarding communication and humaneness predominated (68%). The results indicate that the efforts to reduce patient complaints in HIM should focus on the Relationships domain.

scholarly journals The Quality Lecture: How Do We Rate?

2014 ◽  
Vol 5 (3) ◽  
pp. 710-720
Author(s):  
Tzong-Yang Pan ◽  
Cathy Owen
Keyword(s):  
Staff Development ◽  
Literature Review ◽  
Medical School ◽  
Tertiary Education ◽  
Primary Method ◽  
Visual Aids ◽  
Lecture Series ◽  
Key Concepts ◽  
Key Features

Aims: to review the key features of an effective lecture and to rate a series of medical school lectures to inform a broader initiative in staff development in effective lecturingBackground: Lectures are the primary method of delivering information to an audience in tertiary education and remain a key part of medical school educationMethod: Literature review confirmed fourteen elements thought to contribute to the quality of a lecture. A lecture series was then rated using these criteria Results: The three highest rated criteria were explaining and summarising key concepts, presenting material at an appropriate level to the audience, and the use of clear audio-visual aids and voice. The three lowest rated aspects of our lecture program were stating goals of the talk, monitoring audience understanding and responding appropriately, and providing a conclusion to the talk.Conclusions: These findings will provide direction to staff development to further improve the quality of lectures provided to students. 

E-Shoppers' Perception of Web-Based Decision Aid

2011 ◽  
pp. 451-456
Author(s):  
Fen Wang
Keyword(s):  
Product Information ◽  
Sales Promotion ◽  
Internet Technology ◽  
Online Support ◽  
Purchasing Decisions ◽  
Web Based ◽  
Support Tools ◽  
Key Issues ◽  
Key Features

The WWW, for better or worse, has forever changed the way retailers do business nowadays. E-shoppers, who become more sophisticated and mature nowadays, are demanding increased flexibility and intelligent aids in accessing product information, making purchasing decisions, and obtaining e-services (Anupam, Hull, & Kumar, 2001; Chen, Gillenson, & Sherrell, 2004). The Internet facilitates interactive selling approaches, whereby product offerings can be tailored to individual preferences. It allows e-shoppers to easily gather, retrieve, and analyze product information. Ultimately, the Web offers the ideal vehicle for delivering intelligent online support tools directly to customers (Grenci & Todd, 2002). Unfortunately, most e-commerce sites are rarely aware of taking advantage of such Internet-driven customer aid. Rapid advancements in Internet technology have offered a solution of Web-based customer decision support system (WCDSS) that can improve transactional efficiency by providing tailored merchandising information, offering sales support and consultation, facilitating sales promotion and advertising, and enhancing the consistency, availability and quality of online support to e-shoppers (O’Keefe & Mceachern, 1998). As the WCDSS aims to empower e-shoppers by enabling them to make informed decisions online, the question of how they would perceive such support arises. In this article, we aim to establish a theory-founded framework to understand and explain e-shoppers’ perceptions of the proposed WCDSS functions. We look at the key features of WCDSS functions that may have impact on e-shopper’s perceptions, and how to scale and analyze e-shoppers’ perceptions regarding specific functions. The specific objectives are threefold. We aim (a) to verify the role WCDSS can play in facilitating e-shoppers, (b) to identify the key issues that impact e-shoppers’ perceptions of WCDSS, and (c) to suggest ways in designing and improving WCDSS functions and interfaces.

scholarly journals Side Information Generation Scheme Based on Coefficient Matrix Improvement Model in Transform Domain Distributed Video Coding

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1427
Author(s):  
Wei Wang ◽  
Jianhua Chen
Keyword(s):  
Video Coding ◽  
Side Information ◽  
Coefficient Matrix ◽  
Distributed Video Coding ◽  
Transform Domain ◽  
Entropy Coding ◽  
Coding System ◽  
Optical Flow Method ◽  
Information Generation

In order to effectively improve the quality of side information in distributed video coding, we propose a side information generation scheme based on a coefficient matrix improvement model. The discrete cosine transform coefficient bands of the Wyner–Ziv frame at the encoder side are divided into entropy coding coefficient bands and distributed video coding coefficient bands, and then the coefficients of entropy coding coefficient bands are sampled, which are divided into sampled coefficients and unsampled coefficients. For sampled coefficients, an adaptive arithmetic encoder is used for lossless compression. For unsampled coefficients and the coefficients of distributed video coding coefficient bands, the low density parity check accumulate encoder is used to calculate the parity bits, which are stored in the buffer and transmitted in small amount upon decoder request. At the decoder side, the optical flow method is used to generate the initial side information, and the initial side information is improved according to the sampled coefficients by using the coefficient matrix improvement model. The experimental results demonstrate that the proposed side information generation scheme based on the coefficient matrix improvement model can effectively improve the quality of side information, and the quality of the generated side information is improved by about 0.2–0.4 dB, thereby improving the overall performance of the distributed video coding system.

Paideia, Prejudice and the Promise of the Practical

1998 ◽  
pp. 150-158
Author(s):  
Padraig Hogan
Keyword(s):  
Educational Aspirations ◽  
Educational Practice ◽  
Educational Practices ◽  
Cultural Inheritance ◽  
Cultural Ideals ◽  
Radical Pluralism ◽  
Human Understanding ◽  
The Face ◽  
Key Features

In an age of radical pluralism it is increasingly difficult to affirm and sustain the educational aspirations of Greek paideia (Latin humanitas). The most challenging attacks on these aspirations come from standpoints which share a postmodern attitude of opposition towards inherited cultural ideals, especially those which claim universality. This paper first examines optimistic and pessimistic prospects for the educational heritage of humanitas, concluding that, in the face of cultural disparateness which is increasingly evident in post-Enlightenment cultures, the pessimistic case seems to be more convincing. Recognizing that this gives added impetus to postmodernist standpoints, the second section examines some key features of these, taking as its examples arguments of Lyotard, Foucault and Rorty. I show that the prejudices of the postmodernist arguments are as invidious as the discriminatory assumptions and the neglect of the quality of educational practice in the Western cultural inheritance. Recalling some insights which can be gleaned from the educational practices of Socrates, the last section joins these with findings of contemporary philosophers on the pre-judgements and partiality which are inescapable features of human understanding. This is a reclamation and elucidation of a practical and promising humanitas which does justice to the claims of diversity and universality.

scholarly journals Stepping on the Water

2013 ◽  
Vol 135 (10) ◽  
pp. 38-41
Author(s):  
Adrian Bejan ◽  
Sylvie Lorente
Keyword(s):  
Solid Surfaces ◽  
Maximum Heat ◽  
Animal Locomotion ◽  
Constructal Design ◽  
Maximum Heat Transfer ◽  
Competitive Athletes ◽  
Key Features ◽  
Volumetric Cooling ◽  
Human Running

This study explores various uses of engineering as a tool for solving problems and improving the quality of life. The experiments in the article show that competitive athletes swim with their fingers spread slightly, because this configuration generates greater speed, the research being based on a principle known as constructional law. The constructional law has been applied to predict all the key features of the design of animal locomotion, which includes human running and swimming. In engineering, the discovery expands a domain of constructal-design results that has been growing fast. Bodies that generate heat volumetrically are endowed with maximum heat transfer density when the spacing between the solid surfaces internal to the volume have certain sizes that are smaller in forced convection than in natural convection. The volumetric cooling of future electronics, avionics, and self-cooling materials rests on this class of constructal designs. The swimming with spread fingers is the corresponding design of a body for maximum momentum transfer density.

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