Coventry University

About: Coventry University is a education organization based out in Coventry, United Kingdom. It is known for research contribution in the topics: Population & Higher education. The organization has 4964 authors who have published 12700 publications receiving 255898 citations. The organization is also known as: Lanchester Polytechnic & Coventry Polytechnic.

Optimization of beam orientation in radiotherapy using planar geometry

Abstract: This paper proposes a new geometrical formulation of the coplanar beam orientation problem combined with a hybrid multiobjective genetic algorithm. The approach is demonstrated by optimizing the beam orientation in two dimensions, with the objectives being formulated using planar geometry. The traditional formulation of the objectives associated with the organs at risk has been modified to account for the use of complex dose delivery techniques such as beam intensity modulation. The new algorithm attempts to replicate the approach of a treatment planner whilst reducing the amount of computation required. Hybrid genetic search operators have been developed to improve the performance of the genetic algorithm by exploiting problem-specific features. The multiobjective genetic algorithm is formulated around the concept of Pareto optimality which enables the algorithm to search in parallel for different objectives. When the approach is applied without constraining the number of beams, the solution produces an indication of the minimum number of beams required. It is also possible to obtain non-dominated solutions for various numbers of beams, thereby giving the clinicians a choice in terms of the number of beams as well as in the orientation of these beams.

Strengths and weaknesses of weak-strong cluster problems: A detailed overview of state-of-the-art classical heuristics versus quantum approaches

Abstract: To date, a conclusive detection of quantum speedup remains elusive. Recently, a team by Google Inc. [V. S. Denchev et al., Phys. Rev. X 6, 031015 (2016)] proposed a weak-strong cluster model tailored to have tall and narrow energy barriers separating local minima, with the aim to highlight the value of finite-range tunneling. More precisely, results from quantum Monte Carlo simulations as well as the D-Wave 2X quantum annealer scale considerably better than state-of-the-art simulated annealing simulations. Moreover, the D-Wave 2X quantum annealer is $\ensuremath{\sim}{10}^{8}$ times faster than simulated annealing on conventional computer hardware for problems with approximately ${10}^{3}$ variables. Here, an overview of different sequential, nontailored, as well as specialized tailored algorithms on the Google instances is given. We show that the quantum speedup is limited to sequential approaches and study the typical complexity of the benchmark problems using insights from the study of spin glasses.

Understanding Positive Change Following Trauma and Adversity: Structural Clarification.

Abstract: Growing interest in positive change following trauma and adversity has prompted the development of a number of different labels and measurement instruments. This proliferation has led to some conceptual confusion, due to the different labels being used, and structural confusion, due to the different numbers of underlying factors proposed. The present study addressed both these questions through exploratory principal components analysis of three different growth measures. One hundred seventy six adults (113 women, 63 men), who had experienced a range of distressing life events, completed the Perceived Benefit Scales, the Thriving Scale, and the Posttraumatic Growth Inventory. Results revealed that all subscales loaded highly on a single component, although the possibility of three second-order components of interpersonal relationships, self-perception, and spirituality, was also noted. Discussion focuses on the implications for understanding the concept and structure of positive change following a...