Kinematic Determination of the Aerial Phase in Ski Jumping

The purpose of this study was to find a generic method to determine the aerial phase of ski jumping in which the athlete is in a steady gliding condition, commonly known as the ‘stable flight’ phase. The aerial phase of ski jumping was investigated from a physical point mass, rather than an athlete–action-centered perspective. An extensive data collection using a differential Global Navigation Satellite System (dGNSS) was carried out in four different hill sizes. A total of 93 jumps performed by 19 athletes of performance level, ranging from junior to World Cup, were measured. Based on our analysis, we propose a generic algorithm that identifies the stable flight based on steady glide aerodynamic conditions, independent of hill size and the performance level of the athletes. The steady gliding is defined as the condition in which the rate-of-change in the lift-to-drag-ratio (LD-ratio) varies within a narrow band-width described by a threshold τ. For this study using dGNSS, τ amounted to 0.01s−1, regardless of hill size and performance level. While the absolute value of τ may vary when measuring with other sensors, we argue that the methodology and algorithm proposed to find the start and end of a steady glide (stable flight) could be used in future studies as a generic definition and help clarify the communication of results and enable more precise comparisons between studies.

Immunizing with information – Inoculation messages against conversational agents’ response failures

Conversational agents (CAs) are often unable to provide meaningful responses to user requests, thereby triggering user resistance and impairing the successful diffusion of CAs. Literature mostly focuses on improving CA responses but fails to address user resistance in the event of further response failures. Drawing on inoculation theory and the elaboration likelihood model, we examine how inoculation messages, as communication that seeks to prepare users for a possible response failure, can be used as an alleviation mechanism. We conducted a randomized experiment with 558 users, investigating how the performance level (high or low) and the linguistic form of the performance information (qualitative or quantitative) affected users’ decision to discontinue CA usage after a response failure. We found that inoculation messages indicating a low performance level alleviate the negative effects of CA response failures on discontinuance. However, quantitative performance level information exhibits this moderating effect on users’ central processing, while qualitative performance level information affected users’ peripheral processing. Extending studies that primarily discuss ex-post strategies, our results provide meaningful insights for practitioners.

Evaluasi Struktur Bangunan Pasar Inpress Blok IV Gedung B dengan Metode Pushover

Inpres market block IV Pasar Raya Padang is not designed as a shelter building, but is designated as a vertical evacuation site when a tsunami occurs. This study aims to evaluate the structural performance of Inpress market block IV zone B. The method used for this research is the pushover analysis method. According to FEMA P-646/2019, vertical evacuation refuge structures are included in tsunami risk category IV, based on the risk category the maximum performance level is at the Immediate Occupancy (IO). For loads on buildings, refer to SNI 1727:2020 and SNI 1726:2019 for earthquake loads. For the calculation of the capacity of concrete structural elements, refer to SNI 2847:2019. Structural analysis was carried out using the SAP2000 version 16. After analysis, based on performance points, drift ratio that occur due to earthquake loading in X-direction and Y-direction are 0,05875% and 0,0067%. The maximum total drift that occurs is smaller than that required by ATC-40 for the Immediate Occupancy performance level, which is 1%. Thus, the structure performance level is Immediate Occupancy. This means that the Inpress market block IV building is still strong enough against earthquake loads.

Effects of Training on Cardiorespiratory Fitness in Triathletes: A Systematic Review and Meta-Analysis

Triathlon is an aerobic sport, which is commonly measured by maximal aerobic consumption (VO2max). Objective: to analyze the changes produced in cardiorespiratory and physiological measurements during practice, which determine triathletes’ performance level. A systematic review and a meta-analysis based on PRISMA protocol and registered in PROSPERO (CRD42020189076) was conducted. The research was performed using PubMed, SPORTDiscus, Embase, Dialnet, Web of Science (WOS) and MEDLINE databases during February and March 2020. Studies that measured cardiorespiratory variables in triathletes published in the last 10 years were included. Results: 713 articles were identified, with 25 studies selected for the systematic review and five articles for the meta-analysis. These articles concluded that the main cardiorespiratory variables that determine triathletes’ performance were modified depending on the triathlon segment performed and the athletes’ sex and age. The meta-analysis showed no conclusive results related to the effects of changes in VO2max in triathletes’ performance [SMD = −0.21; 95%CI: (−0.84 to 0.43)]. Conclusions: cardiorespiratory fitness, in terms of VO2max and ventilatory thresholds, is the strongest predictor of performance in triathlon. This response may be affected depending on the triathlon segment performed and the athlete’s age or sex, leading to both physiological and biomechanical alterations that affect competition performance.

Farmers’ Capacity and Rice Productivity in Climate Change Adaptation in Central Lampung Regency, Indonesia

Climate change is an extreme natural change condition due to global warming that cannot be avoided, and will have a broad impact on various aspects of life, including the agricultural sector. The impact of climate change that occurs in the agricultural sector, namely flood and drought that cause plants to crop failure , is becoming greater, causing significant reduction in agricultural production, especially rice, requiring that farmers have the ability to adapt to climate change. The purposes of this study are to analyze the relationship between the performance level of agricultural extension workers and the capacity level of farmers in regard to climate change adaptation, and to analyze the relationship between the level of farmer capacity in climate change adaptation and rice productivity. The research was conducted in Central Lampung Regency in 2019 using a total of 100 rice farmers. The data analysis method used is Spearman rank correlation analysis. The results show that the performance level of agricultural instructors is significantly related to the level of knowledge capacity, attitude, and skills of farmers in climate change adaptation. Knowledge capacity, attitude, and skills of farmers in climate change adaptation are significantly related to rice productivity.

Competence-based fuzzy skill functions

Fuzzy skill functions connect knowledge states at the performance level with latent cognitive abilities at the competence level. Given that there may exist precedence relations among skills, the main idea of this study is trying to develop fuzzy competence structures restricted on the possible fuzzy sets of skills that can occur. The knowledge structures delineated by fuzzy skill functions are related to the fuzzy competence structures. Knowledge spaces can be delineated by disjunctive fuzzy skill functions when the fuzzy competence structures are $\sqcup$-closed. Simple closure spaces can be delineated by conjunctive fuzzy skill functions when the fuzzy competence structures are $\sqcap$-closed. Delineating knowledge structures via competence-based fuzzy skill functions just depends on the effective competence states. We design algorithms for delineating knowledge structures via competence-based fuzzy skill functions without listing all fuzzy competence states of fuzzy competence structures.

Sequencing of multi-robot behaviors using reinforcement learning

Given a collection of parameterized multi-robot controllers associated with individual behaviors designed for particular tasks, this paper considers the problem of how to sequence and instantiate the behaviors for the purpose of completing a more complex, overarching mission. In addition, uncertainties about the environment or even the mission specifications may require the robots to learn, in a cooperative manner, how best to sequence the behaviors. In this paper, we approach this problem by using reinforcement learning to approximate the solution to the computationally intractable sequencing problem, combined with an online gradient descent approach to selecting the individual behavior parameters, while the transitions among behaviors are triggered automatically when the behaviors have reached a desired performance level relative to a task performance cost. To illustrate the effectiveness of the proposed method, it is implemented on a team of differential-drive robots for solving two different missions, namely, convoy protection and object manipulation.

Mental Toughness and Motivational Climate of Basketball Players According to Gender and Age Groups

Background: It has been a matter of curiosity by athletes, coaches, sports commentators, and sports psychologists why certain athletes are the world's best in their field. Aim: In our study, the mental toughness and motivational climates of licensed basketball players were examined according to age and gender variables. Methods: In this study, the relational screening model was used to determine the relationship between mental toughness and motivational climate in licensed basketball players studying in physical education and sports teaching departments. Results: As a result of this study, where mental toughness and motivational climate, which are known to be necessary to maintain the ideal performance level during competition, are evaluated according to age and gender variables, it is seen that the motivational climate and mental toughness scores do not differ according to the gender of the athletes. Conclusion: As a result of this study, where mental toughness and motivational climate, which are known to be necessary to maintain the ideal performance level during competition, are evaluated according to age and gender variables, it is seen that the motivational climate and mental toughness scores do not differ according to the gender of the athletes. Keywords: Mastery Climate, Performance Climate, Mental Toughness, Age, Gender