Another look at the shoelace TSP : the case of very old shoes

What is the most efficient way of lacing a shoe? Mathematically speaking, this question concerns the structure of certain special cases of the bipartite travelling salesman problem (BTSP). We show that techniques developed for the analysis of the (standard) TSP may be applied successfully to characterize well-solvable cases of the BTSP and the shoelace problem. In particular, we present a polynomial time algorithm that decides whether there exists a renumbering of the cities such that the resulting distance matrix carries a benevolent combinatorial structure that allows one to write down the optimal solution without further analysis of input data. Our results generalize previously published well-solvable cases of the shoelace problem. Keywords: Bipartite travelling salesman problem; shoelace problem; polynomially solvable case; relaxed Monge matrix; pick-and-place robo

OTIMIZAÇÃO DO PROCESSO DE INSERÇÃO AUTOMÁTICA DE COMPONENTES ELETRÔNICOS EMPREGANDO A TÉCNICA DE TIMES ASSÍNCRONOS

Este trabalho apresenta um sistema computacional que busca otimizar o processo de inserção automática de componentes eletrônicos com a máquina Panasert AVK, baseada na técnica de times assíncronos (A-Teams). É feita a formulação do problema de inserção e apresentada a arquitetura do sistema. Por último, são apresentados os resultados obtidos e conclusões inferidas, demonstrando a viabilidade da utilização desta técnica nesta classe de problemas.<br>This paper presents a computational system which aims to optimize the automatic insertion process of electronic components with the Panasert AVK machine, based on asynchronous teams (A-Teams). A formulation of the insertion problem is proposed and the architecture of the system is presented. Finally, the obtained results and inferred conclusions are presented, showing the viability of this technique when applied in this class of problems

Auditory event-related potentials are related to cognition at preschool age after very preterm birth.

Background:Auditory event-related potentials (AERP) are neurophysiological correlates of sound perception and cognitive processes. Our aim was to study in very preterm born children at preschool age if AERP correlate with cognitive outcome.Methods:Seventy children (mean ± SD gestational age 27.4 ± 1.9 wk, birth weight 996 ± 288 g) were investigated at age 4.3-5.3 y with psychological testing (WPPSI-R, four subtests of NEPSY). Electroencephalogram was recorded while they listened to a repeated standard tone, randomly replaced by one of three deviants. Latencies and amplitudes for AERP components and mean amplitudes in successive 50-ms AERP time windows were measured.Results:Better cognitive test results and higher gestational age correlated with shorter P1 latencies and more positive mean amplitudes 150-500 ms after stimulus change onset. Neonatal brain damage was associated with a negative displacement of AERP curves. Neonatal morbidity had an impact on earlier time windows while gestational age and brain damage on both early and later time windows.Conclusion:AERP measures were associated with cognitive outcome. Neonatal morbidity mainly affects early cortical auditory encoding, while immaturity and brain damage additionally influence higher cortical functions of auditory perception and distraction. Perinatal auditory environment might play a role in development of auditory processing.Pediatric Research (2015); doi:10.1038/pr.2015.7