Hierarchical linear dynamical systems for unsupervised musical note recognition     

Goktug T. Cinar  Pedro M.N. Sequeira  Jose C. Principe 《Journal of The Franklin Institute》2018,355(4):1638-1662

In this paper we develop a new framework for time series segmentation based on a Hierarchical Linear Dynamical System (HLDS), and test its performance on monophonic and polyphonic musical note recognition. The center piece of our approach is the inclusion of constraints in the filter topology, instead of on the cost function as normally done in machine learning. Just by slowing down the dynamics of the top layer of an augmented (multilayer) state model, which is still compatible with the recursive update equation proposed originally by Kalman, the system learns directly from data all the musical notes, without labels, effectively creating a time series clustering algorithm that does not require segmentation. We analyze the HLDS properties and show that it provides better classification accuracy compared to current state-of-the-art approaches.  相似文献   

Truncation error analysis in computing of SEP and SEP floor for partially coherent receiver of MPSK signals over composite fading channels     

Zvezdan M. Marjanović  Goran T. Djordjević  Gradimir V. Milovanović 《Journal of The Franklin Institute》2018,355(2):965-980

In this paper, we analyze detection of multilevel phase-shift keying (MPSK) signals transmitted over a Gamma shadowed Nakagami-m fading channel. We derive novel analytical expression, in terms of Meijer’s G function, for Fourier coefficients of the probability density function of the received signal composite phase. Under the assumption of the imperfect reference signal extraction in the receiver, which is performed from the pilot signal, the analytical expression is derived for the symbol error probability (SEP) in the form of convergent series. The existence of the error floor is identified, and expression for its computation is provided. Mathematical proofs for convergence of Fourier series are provided for both SEP and SEP floor, and novel expressions of upper bounds for truncation errors are derived in terms of elementary mathematical functions. The convergence rate of the derived expressions is examined. Numerical results are confirmed independently by Monte-Carlo simulations.  相似文献   

Joint ventures and technology adoption: A Chinese industrial policy that backfired     

Sabrina T. Howell 《Research Policy》2018,47(8):1448-1462

To spur technology transfer, emerging market policymakers often require foreign firms to form joint ventures (JVs) with domestic firms. Through knowledge spillovers, JVs may reduce technology acquisition costs for domestic firms. Yet domestic firm rents from JVs could discourage innovation through a cannibalization effect. Which force dominates is an empirical question. I address it with novel data on China's auto sector. In response to fuel economy standards requiring firms to upgrade technology or sacrifice quality, firms with JVs reduced quality and price relative to their counterparts. Consistent with cannibalization, firms with JVs drive the negative effect.  相似文献   

Relationships between highly skilled golfers’ clubhead velocity and force producing capabilities during vertical jumps and an isometric mid-thigh pull     

Jack E. T. Wells  Andrew C. S. Mitchell  Laura H. Charalambous  Iain M. Fletcher 《Journal of sports sciences》2018,36(16):1847-1851

Whilst previous research has highlighted significant relationships between golfers’ clubhead velocity (CHV) and their vertical jump height and maximum strength, these field-based protocols were unable to measure the actual vertical ground reaction force (vGRF) variables that may correlate to performance. The aim of this study was to investigate relationships between isometric mid-thigh pull (IMTP), countermovement jump (CMJ), squat jump (SJ) and drop jump (DJ) vGRF variables and CHV in highly skilled golfers. Twenty-seven male category 1 golfers performed IMTP, CMJ, SJ and DJ on a dual force platform. The vertical jumps were used to measure positive impulse during different stretch-shortening cycle velocities, with the IMTP assessing peak force (PF) and rate of force development (RFD). Clubhead velocity was measured using a TrackMan launch monitor at a golf driving range. Pearsons correlation coefficient analyses revealed significant relationships between peak CHV and CMJ positive impulse (r = 0.788, p < 0.001), SJ positive impulse (r = 0.692; p < 0.001), DJ positive impulse (r = 0.561, p < 0.01), PF (r = 0.482, p < 0.01), RFD from 0–150 ms (r = 0.343, p < 0.05) and RFD from 0–200 ms (r = 0.398, p < 0.05). The findings from this investigation indicate strong relationships between vertical ground reaction force variables and clubhead velocity.  相似文献   

eSport: Vom Präfix zum Thema für den organisierten Sport!?     

T. Wendeborn  H. J. Schulke  A. Schneider 《Sportwissenschaft》2018,48(3):451-455

In an increasingly differentiated culture of movement, play and sport as well as a more and more digitized society, the topic of eSports has been intensively discussed in recent time. The objective-categorical basics of the discussion seem to be clear only at first sight. A closer look points to the need of a differentiated cross-disciplinary discussion of the topic. It becomes clear that above all the underlying understanding of sport, the content-related demarcation as well as the social positioning contribute decisively to the perception of eSport (approval/rejection). The present article takes up the discussion with reference to the heterogeneity, heteronomy and complexity of sports and provides an alternative interpretive idea on the topic.  相似文献   

Beyond health messaging: a behavioural economics approach to increasing self-selected distance during an acute bout of cycling     

Aaron T. Piepmeier  Jennifer L. Etnier  Kimberly S. Fasczewski 《European Journal of Sport Science》2018,18(9):1264-1270

The purpose of this study was to explore the effects of the perceived purpose of exercising on the self-selected distance peddled during an acute cycling task. Participants were randomly assigned to one of three groups (health, wealth, charity). All participants watched a video emphasizing the health benefits of performing at least 30?min of daily exercise. Those in the health group were not provided any additional information. Those in the wealth group were then informed that they would earn money for every two kilometres cycled. Those in the charity group were informed that they would earn money for a charity for every two kilometres cycled. Participants were not given a time/distance limit and were instructed to cycle until they chose to stop. Analyses revealed that participants in the wealth and charity group cycled significantly farther than those in the health group (approximately twice as far). Additionally, a significant sex by group interaction showed that women cycled farther for charity while men cycled farther for wealth. These results suggest that health messages used to increase exercise behaviour may benefit from exploring how paradigms from behavioural economics influence behaviors that have relevance to public health.  相似文献   

Decrements in knee extensor and flexor strength are associated with performance fatigue during simulated basketball game-play in adolescent,male players     

Aaron T Scanlan  Jordan L Fox  Nattai R Borges  Anne Delextrat  Tania Spiteri  Vincent J Dalbo 《Journal of sports sciences》2018,36(8):852-860

This study quantified lower-limb strength decrements and assessed the relationships between strength decrements and performance fatigue during simulated basketball. Ten adolescent, male basketball players completed a circuit-based, basketball simulation. Sprint and jump performance were assessed during each circuit, with knee flexion and extension peak concentric torques measured at baseline, half-time, and full-time. Decrement scores were calculated for all measures. Mean knee flexor strength decrement was significantly (P < 0.05) related to sprint fatigue in the first half (R = 0.65), with dominant knee flexor strength (R = 0.67) and dominant flexor:extensor strength ratio (R = 0.77) decrement significantly (P < 0.05) associated with sprint decrement across the entire game. Mean knee extensor strength (R = 0.71), dominant knee flexor strength (R = 0.80), non-dominant knee flexor strength (R = 0.75), mean knee flexor strength (R = 0.81), non-dominant flexor:extensor strength ratio (R = 0.71), and mean flexor:extensor strength ratio (R = 0.70) decrement measures significantly (P < 0.05) influenced jump fatigue during the entire game. Lower-limb strength decrements may exert an important influence on performance fatigue during basketball activity in adolescent, male players. Consequently, training plans should aim to mitigate lower-limb fatigue to optimise sprint and jump performance during game-play.  相似文献   

The association between fundamental athletic movements and physical fitness in elite junior Australian footballers     

Carl T. Woods  Ian McKeown  Justin Keogh  Sam Robertson 《Journal of sports sciences》2018,36(4):445-450

This study investigated the associations between fundamental athletic movement and physical fitness in junior Australian football (AF). Forty-four under 18 players performed a fundamental athletic movement assessment consisting of an overhead squat, double lunge, single leg Romanian deadlift and a push up. Movements were scored on three assessment criterions using a three-point scale. Additionally, participants performed five physical fitness tests commonly used for talent identification in AF. A Spearman’s nonparametric correlation matrix was built, with correlation coefficients being visualised using a circularly rendered correlogram. Score on the overhead squat was moderately positively associated with dynamic vertical jump height on left (r_s = 0.40; P ≤ 0.05) and right (r_s = 0.30; P ≤ 0.05) leg take-off, stationary vertical jump (r_s = 0.32; P ≤ 0.05) and negatively associated with 20-m sprint time (r_s = ?0.35; P ≤ 0.05). Score on the double lunge (left/right side) was moderately positively associated with the same physical fitness tests as well as score on the multistage fitness test. Results suggest that improvements in physical fitness qualities may occur through concurrent increases in fundamental athletic movement skill, namely the overhead squat and double lunge movements. These findings may assist with the identification and development of talent.  相似文献   

Pre-service teachers in an after school program: increasing understanding of students,communities, and teaching     

Sarah F. Vess  Leslie M. Cavendish  Kirsten T. Li-Barber 《Teaching Education》2018,29(3):251-260

The purpose of the After School Creative Expression Program (ASCEP) was to provide a short-term afterschool program focusing on the visual and written creative arts to a group of elementary school children attending a Title 1 school. Pre-service teachers attending a liberal arts university within the same geographic region developed lessons in writing and photography and served as afterschool educators for ASCEP. The program provided pre-service teachers a valuable experience outside the classroom. Findings demonstrate pre-service educators gained new insights from ASCEP that will impact their teaching practices during school. Overall, results show ASCEP provided future educators with valuable learning experiences and opportunities to connect more deeply with their students and their community.  相似文献   

Using the Blended Learning Approach in a Quantitative Literacy Course     

Ryan T. Botts  Lori Carter 《PRIMUS》2018,28(3):236-265

The efforts to improve the quantitative reasoning (quantitative literacy) skills of college students in the United States have been gaining momentum in recent years. At the same time, the blended learning approach to course delivery has gained in popularity, promising better learning with flexible modalities and pace. This paper presents the results of an exploratory study that compares student learning outcomes and student attitudes over several semesters of blended versus traditional delivery in the upper-division quantitative literacy course at Point Loma Nazarene University.  相似文献