A Scheduling Method of Using Multiple SAR Satellites to Observe a Large Area.

This paper presents a scheduling problem of using multiple synthetic aperture radar (SAR) satellites to observe a large irregular area (SMA). SMA is usually considered as a kind of nonlinear combinatorial optimized problem and its solution space strongly coupled with geometry grows exponentially with the increasing magnitude of SMA. It is assumed that each solution of SMA yields a profit associated with the acquired portion of the target area, and the objective of this paper is to find the optimal solution yielding the maximal profit. The SMA is solved by means of a new method composed of three successive phases, namely, grid space construction, candidate strip generation and strip selection. First, the grid space construction is proposed to discretize the irregular area into a set of points in a specific plane rectangular coordinate system and calculate the total profit of a solution of SMA. Then, the candidate strip generation is designed to produce numerous candidate strips based on the grid space of the first phase. At last, in the strip selection, the optimal schedule for all the SAR satellites is developed based on the result of the candidate strip generation. In addition, this paper proposes a normalized grid space construction algorithm, a candidate strip generation algorithm and a tabu search algorithm with variable neighborhoods for the three successive phases, respectively. To verify the effectiveness of the proposed method in this paper, we perform simulation experiments on several scenarios and compare our method with the other seven methods. Compared to the best of the other seven methods, our proposed method can improve profit by 6.38% using the same resources.

Core strength training impacts on the improvement of muscle coordination in sport dancers / Treinamento de força do core na melhoria da coordenação muscular em dançarinos esportivos / Entrenamiento de la fuerza del core en la mejora de la coordinación muscular en bailarines deportivos

ABSTRACT Introduction: Dance sport is an emerging sport activity. The number of college students devoted to the study of dance is increasing. Basic dance sport skills are inherent to performance. Basic skills training requires dancers to have a certain degree of flexibility, endurance, speed, etc. Currently, we know that CORE strength training can improve the physical function of athletes, but studies are scarce as to its true impact on proprioceptive skills in dance sports. Objective: The purpose of this study was to examine the effect of strengthening the CORE on muscle coordination in sport dancers. This paper examines the relationship between core strength training and dance skills in athletes. Methods: Undergraduate sport dance students were randomly and voluntarily selected. These students undergo a 4-month training protocol in CORE strengthening. The effect of this experiment was evaluated with biomarker and kinetic data collected before and after the experiment. These data were worked out statistically and the results were discussed according to the literature. Results: After the CORE training protocol, the sport dance students had significant differences in physical tests(P<0.05). Conclusion: CORE training can promote physical stability, explosive power and muscle coordination in sport dancers. Level of evidence II; Training research - outcome investigation.

RESUMO Introdução: O esporte de dança é uma atividade esportiva emergente. O número de estudantes universitários dedicados ao estudo da dança está aumentando. As habilidades básicas da dança esportiva são inerentes à performance. O treinamento de habilidades básicas exige que os dançarinos tenham um certo grau de flexibilidade, resistência, velocidade, etc. Atualmente, sabemos que o treinamento de força do core pode melhorar a função física dos atletas, porém os estudos são escassos quando ao seu verdadeiro impacto sobre as habilidades proprioceptivas na dança esportiva. Objetivo: Este estudo teve como objetivo analisar o efeito do fortalecimento do core na coordenação muscular em bailarinos esportivos. Este artigo examina a relação entre treinamento de força central e habilidades de dança em atletas. Métodos: Foram selecionados, de maneira aleatória e voluntariamente, universitários graduandos em dança esportiva. Esses alunos passam por 4 meses sob protocolo de treino em fortalecimento do core. O efeito desse experimento foi avaliado com os dados de biomarcadores e cinéticos coletados antes e após o experimento. Esses dados foram trabalhados estatisticamente e os resultados foram discutidos segundo a literatura. Resultados: Após o protocolo de treinamento do core, os alunos de dança esportiva tiveram diferenças significativas nos testes físicos (P<0,05). Conclusão: O treinamento do core pode promover estabilidade física, poder explosivo e coordenação muscular em dançarinos esportivos. Nível de evidência II; Pesquisa de treinamento - investigação de resultados.

RESUMEN Introducción: El deporte de la danza es una actividad deportiva emergente. El número de universitarios dedicados al estudio de la danza va en aumento. Las habilidades deportivas básicas de la danza son inherentes al rendimiento. El entrenamiento de habilidades básicas requiere que los bailarines tengan un cierto grado de flexibilidad, resistencia, velocidad, etc. Hoy en día, sabemos que el entrenamiento de fuerza core puede mejorar la función física de los atletas, pero los estudios son escasos sobre su impacto real en las habilidades propioceptivas en los deportes de danza. Objetivo: Este estudio tiene como objetivo analizar el efecto del fortalecimiento del core en la coordinación muscular de los bailarines deportivos. Este artículo examina la relación entre el entrenamiento de la fuerza central y las habilidades de danza en los atletas. Métodos: Se seleccionaron de forma aleatoria y voluntaria estudiantes universitarios que se graduaban en danza deportiva. Estos estudiantes pasaron 4 meses bajo el protocolo de formación en el fortalecimiento del core. El efecto de este experimento se evaluó con datos de biomarcadores y cinéticos recogidos antes y después del experimento. Estos datos se trabajaron estadísticamente y los resultados se discutieron de acuerdo con la literatura. Resultados: Tras el protocolo de entrenamiento del core, los alumnos de danza deportiva presentaron diferencias significativas en las pruebas físicas (P<0,05). Conclusión: El entrenamiento del core puede promover la estabilidad física, la potencia explosiva y la coordinación muscular en los bailarines deportivos. Nivel de evidencia II; Investigación de formación - investigación de resultados.

Implementation of a Phase Synchronization Scheme Based on Pulsed Signal at Carrier Frequency for Bistatic SAR.

Phase synchronization is one of the key technical challenges and prerequisites for the bistatic synthetic aperture radar (SAR) system, which can form a single-pass interferometry system to perform topographic mapping. In this paper, an advanced phase synchronization scheme based on a pulsed signal at carrier frequency is proposed for a bistatic SAR system and it is verified by a ground validation system. In the proposed phase synchronization scheme, the pulsed signal at carrier frequency is used for phase synchronization link, and it is exchanged by virtue of a time slot between radar signals. The feasibility of the scheme is proven by theoretical analysis of various factors affecting the performance of phase synchronization, and the reliability of the scheme is verified by the test results of the ground validation system.