RHONN identifier-control scheme for nonlinear discrete-time systems with unknown time-delays

This work presents a neural identifier-control scheme for uncertain nonlinear discrete-time systems with unknown time-delays. This scheme is based on a neural identifier to get a model of the system and a discrete-time block control technique based on sliding modes to generate the control law. The neural identifier is based on a Recurrent High Order Neural Network (RHONN) trained with an Extended Kalman Filter (EKF) based algorithm. Applicability is shown using real-time test results for linear induction motors. Also, a Lyapunov analysis is added in order to prove the semi-globally uniformly ultimately boundedness (SGUUB) of the proposed neural identifier-control scheme.     

Robust sensorless observer-based adaptive sliding modes control of synchronous motors

Using a nonlinear complete order model of a synchronous motor, a robust second order sliding mode observer based control scheme is proposed. For that, a generalized super-twisting 3rd order observer is proposed for nonlinear systems. Based on the proposed observer scheme, a robust rotor flux observer is designed, then, a stator current observer is proposed using a classical super-twisting algorithm for extracting information of the rotor speed by means of the equivalent control method. The control design for the output tracking of a desired reference signal for the rotor speed is carried out with a classical super-twisting sliding mode algorithm and adaptive backstepping techniques. Due to the number of inputs, the flux in the excitation winding, and the direct component of the stator currents are also regulated. Numeric simulations predict a good performance of the closed-loop synchronous motor with parameter variations.     

Uncovering the link between governance as an innovation process and socio-economic regime transition in cities

A major proportion of the world’s population will be located in cities by 2030. With cities globally facing challenges due to the social exclusion of significant proportions of their populace, new thinking is needed on ways to correlate the competing socio-economic goals of various actors. This study sought to uncover the link between governance in cities as an innovation process and socio-economic regime transition towards a more equitable urban society. To do so, we draw on transition management thinking to consider urban regime transitions evolving in a temporal and incremental manner and in a multi-level context. We sought expansion from a delimited focus on socio-technical regimes in transition management literature to incorporate the notion of urban socio-economic regimes. This involved integrating aspects of reflexive governance and politics in a city context with a basic ontology of complex social systems and their evolutionary dynamics that underlies transition management approaches. Our focus is on learning by doing and experimentation as well as participation of citizens with other key city actors in a radically new process of mutual learning that creates social inclusion. The juxtaposition of national, city and community level interactions and their impact on socio-economic regime transition brings into sharp relief the issue of spatial scale and a lack of consideration in transition approaches generally. The study findings reveal a spatial orientation for creating new urban forms of reflexive governance as an innovation process taking place in transition arenas that can trigger new pathways to socio-economic change.     

Drivers of spin-off performance in industry clusters: Embodied knowledge or embedded firms?

Numerous studies attest to the distinctive performance of intra-industry spin-offs located in agglomerated regions. Besides entrepreneurs’ pre-entry experience, both superior hires and regional embeddedness have been suggested as factors contributing to this pattern. We employ linked employer-employee data to assess their relevance in the empirical context of the Portuguese plastic injection molds industry. We find that the longevity of entrants is associated with the number and quality of early employees hired from within the industry, consistent with the importance of embodied knowledge flows. Our findings do not suggest that entrants’ centrality in the regional industry network enhances their longevity.     

Towards the use of multidimensional performance indicators in football small-sided games: the effects of pitch orientation

This study aimed to compare youth football players’ performance during two small-sided games with different pitch orientation: i) 40x30m and ii) 30x40m formats. Twenty under-15 players (age = 14.1 ± 0.5 years) participated in nine GK+4vs4+GK situations in each format, with the duration of six minutes each. Positional data were collected using individual GPS units, and computed for tactical and physical performance indicators. The SSG were video recorded, using notational analysis for collecting technical indicators. A novel method that incorporates time dependent notational information with spatiotemporal data was used to compute multidimensional parameters. Standardised effect sizes and non-clinical magnitude-based inferences were used to compare formats. Results showed that players covered more distance at higher intensities, presented more passes and dribbles and were more synchronised in the longitudinal axis while playing in the 40x30m pitch. In the 30x40m pitch, results showed a lower distance between team centroids, higher number of shots, more lateral passes and a wider team positioning. Multidimensional indicators, as players position and distance to the closest defender while shooting, revealed a more constant distance between attacker and defender in the 40x30m pitch. These results highlight the importance of integrating information from different indicators for a contextually valid information.     

Start and turn performances of elite sprinters at the 2016 European Championships in swimming

The aim of this study was to examine the performance characteristics of male and female finalists in the 100-m distance at the 2016 European Championships in swimming (long-course-metre). The performances of all 64 (32-males and 32-females) were analysed (8 swimmers per event; Freestyle, Backstroke, Breaststroke and Butterfly). A set of start and turn parameters were analysed. In the start main outcome, male swimmers were faster in Butterfly (5.71 ± 0.14s) and females in Freestyle (6.68 ± 0.28s). In the turn main outcome, male and female swimmers were faster in Freestyle (males: 9.55 ± 0.13s; females: 10.78 ± 0.28s). A significant and strong stroke effect was noted in the start and turn main outcome, in both sexes. In the start plus the turn combined, males and females were faster in Freestyle (males: 15.40 ± 0.20s; females: 17.45 ± 0.54s). The start and the turn combined accounted almost one-third of the total race time in all events, and non-significant differences (p > 0.05) were noted across the four swim strokes. Once this research made evident the high relevance of start and turns, it is suggested that coaches and swimmers should dedicate an expressive portion of the training perfecting these actions.     

Motor fitness and preschooler children obesity status

The aim of this study was to examine the association between motor fitness (MF) and obesity status in preschool children.

The sample comprised 467 children aged 3–6 years. Preschool children body mass index was classi?ed according to International Obesity Task Force and categorised into three levels, normal, overweight and obesity. Total physical activity was assessed by accelerometer and MF test was assessed through two MF tests 10 × 5m shuttle run test (SRT) and a 7 m jumping distance on 2 feet test (J2F). Low MF was considered for MF if SD above 1. A single variable with three categories was created: low MF medium MF and high MF.

The prevalence of normal weight, overweight and obesity was 67.6%, 22.7% and 9.7%, respectively. The prevalence of SD > 1 for SRT was 13.7% and 14.4% for J2F, for single variable was 19.2%. Multinomial logistic regression analysis showed that obese preschoolers were more likely six times classified as having low MF level than their non-overweight counterparts (OR: 6.4; IC: 1.3–36.6).

This study showed a considerable prevalence of overweight and obesity among preschoolers. Obesity has already been associated with lower MF. Further longitudinal studies are needed to con?rm this data.     

奥林匹克多元文化主义:走向文化相对主义

"7月9日,当世界杯足球赛决赛在柏林开赛时,这个星球上的五分之一人口,即10多亿人将在观看同一电视画面,这是世界历史进程中的一个新标志.     

The new supply chain's frontier: Information management

The purpose of this paper is to understand the key issues faced by supply chain (SC), current strategies and trends of this field, understand IT technical issues and implication for business performance and how IT can foster IM and help sort out the SC problems. Studies from different and recognised authors are reviewed, compiled and analysed in two aspects. First, a detailed picture of SC trends, issues and strategies is depicted. After, main concerns about IT, such as its goals, importance, pitfalls, and features are presented. Moreover, current applications of IT in SC and critical problems and competitive advantages in the IT implementation in the supply chain management's competitive priorities are detailed. SC's new configuration and reality have increased the level of uncertainties and risks present in supply chain activities. Some strategies to mitigate these problems have undermined the SC efficiency. Therefore, a new strategy that uses IT to make SC more robust and resilient should be developed. As a holistic problem, a modelling approach (SDDES) should be used as a tool to support this study.