Optimal Rendezvous Trajectory Using a Hybrid Approach

Abstract — Genetic algorithms have gained popularity as effective search procedures for obtaining solutions to traditionally difficult space mission optimization problems. In this paper, a real-coded genetic algorithm is used together with calculus of variations to optimize a trajectory for rendezvous problem. The global search properties of genetic algorithm combine with the local search capabilities of calculus of variations to produce solutions that are superior to those generated with the calculus of variations alone, and these solutions require less user interaction than previously possible. The genetic algorithm is not hampered by ill-behaved gradients and is relatively insensitive to problems with a small radius of convergence. The use of calculus of variations within the genetic algorithm optimization routine increases the precision of the final solution to levels uncommon for a genetic algorithm alone

Educational challenges of postgraduate neonatal intensive care nursing students: A qualitative study

INTRODUCTION: Despite the progress of health care and the application of new technology in the care of patients, the need to train highly skilled and specialized nurses is inevitable. Given that a master's degree in neonatal intensive care nursing has been recently established in Iran, the aim of the study was to explain the educational challenges of neonatal intensive care postgraduate nursing students in their perspective. MATERIALS AND METHODS: This conventional content analysis was performed by conducting semi-structured interviews with 18 students of neonatal intensive care in X University of Medical Sciences from 2018 to 2019. Data were analyzed using conventional content analysis. To establish the reliability and validity of findings, Graneheim and Landman criteria were considered. RESULTS: Following the data analysis, two main categories were extracted: 'theoretical education challenges' and 'clinical education challenges.' The first main category was comprised of the following subcategories: 'detachment of nursing department and hospital,' 'defects in weekly scheduling,' 'combination of care and treatment approaches in education,' 'inconsistency between the content of theoretical courses,' 'limited collaboration between basic science and medical departments,' 'low number of lecturers,' 'lecturers' unrealistic expectations,' and 'the importance of the scoring system.' 'Extended work shifts,' 'a large number of students,' 'lack of opportunity to do clinical practices,' 'lack of training classes,' and 'limited amenities in the hospital' were recognized as subcategories of the second category. CONCLUSION: Managers can address some of the students' challenges and provide the opportunity to enhance the quality of education through being familiar with, considering and meetings the needs and expectations of these students. © 2020 Wolters Kluwer Medknow Publications. All rights reserved