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Yumi : łuk w historii i kulturze Wysp Japońskich

Puchalska Joanna

Kwartalnik Bellona

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2022

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Nr 4

71--86

PL

W artykule omówiono tradycyjny, długi, asymetryczny łuk japoński yumi oraz sposób jego wykorzystania na przestrzeni dziejów. Przedstawiono podstawowe informacje o konstrukcji i działaniu tej broni oraz jej specyficzne cechy, a także wskazano metody strzelania. Przybliżono historię wykorzystywania łuku przez Japończyków, z uwzględnieniem ważnej roli, jaką odgrywał on w sztuce wojennej samurajów w pierwszych wiekach ich supremacji na arenie politycznej kraju. Omówiono również zmiany w sztuce militarnej Japonii zapoczątkowane w połowie drugiego tysiąclecia naszej ery, wynikające ze zwiększenia liczebności armii oraz pojawienia się na japońskich polach bitew broni palnej. W artykule zwrócono uwagę także na obecność łuku yumi w sferze religijnej Japończyków oraz wykorzystanie go we współczesnej kulturze Japonii, od sztuk walki i rekonstrukcji historycznych po święta i festiwale matsuri.

EN

The article is dedicated to the traditional asymmetric Japanese longbow - yumi - and how it was used throughout the centuries. The initial part of the text introduces key information on the construction and operation of the yumi, detailing the specific features of this weapon and its methods of shooting. Subsequently, the history of the Japanese bow is discussed, taking into consideration the important role the yumi played in the samurai warfare during the first centuries of their supremacy in the country's political arena, as well as significant changes in the Japanese military in the middle of the second millennium CE, namely growing size of the armies and the introduction of firearms. The last part of the article discusses yumi's presence in the Japanese religious sphere and the usage of the bow in contemporary Japanese culture, from martial arts and historical reenactments to matsuri festivals.

2

The application of topological data analysis to human motion recognition

Żelawski Marcin, Hachaj Tomasz

Technical Transactions

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2021

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Vol. 118, iss. 1

art. no. e2021011

EN

Human motion analysis is a very important research topic in the field of computer vision, as evidenced by a wide range of applications such as video surveillance, medical assistance and virtual reality. Human motion analysis concerns the detection, tracking and recognition of human activities and behaviours. The development of low-cost range sensors enables the precise 3D tracking of body position. The aim of this paper is to present and evaluate a novel method based on topological data analysis (TDA) for motion capture (kinematic) processing and human action recognition. In contrast to existing methods of this type, we characterise human actions in terms of topological features. The recognition process is based on topological persistence which is stable to perturbations. The advantages of TDA are noise resistance and the ability to extract global structure from local information. The method we proposed in this paper deals very effectively with the task of human action recognition, even on the difficult classes of motion found in karate techniques. In order to evaluate our solution, we have performed three-fold cross-validation on a data set containing 360 recordings across twelve motion classes. The classification process does not require the use of machine learning and dynamical systems theory. The proposed classifier achieves a total recognition rate of 0.975 and outperforms the state-of-theart methods (Hachaj, 2019) that use support vector machines and principal component analysis-based feature generation.

3

Relationship of maximal isometric torque produced in flexors and extensors rate to technique by judo athletes

Sterkowicz S., Lech G., Sterkowicz-Przybycień K., Chwała W., Ambroży T., Pałka T.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

65--71

EN

Purpose: Development of strength is one of essential elements of motor preparation of judo athletes. The aim this study was to examine the influence of body composition and the joint torques on successful performance of various judo techniques. Methods: Twentyfive judo athletes participated in 175 judo bouts, which were video-recorded during the All-Polish competitions. Biomechanical classification of technical actions was used. The age and athletic experience of the subjects were 18 and 8.8 years, respectively. Their body height was 179.4 cm (Martin’s type anthropometer) and body mass was 80.3 kg (Sartorius F 1505 – DZA scales). Percentage of fat (10.6%) was estimated using skinfold result measurements. BMI (24.9 kgm–2), fat-free mass index (21.9 kgm–2) and fat mass index (3.0 kgm–2) were calculated. Maximum torques measured under static conditions were evaluated 2–3 days after the tournament. Descriptive statistics and ANOVA were conducted ( p  0.05). Results: Balancing of maximum torques in the muscles of the pelvic and illiac regions caused more frequent performance of physical lever-type throwing techniques, compared to couple of force-type throwing techniques. A negative correlation was found between body fat and value of force recorded for knee flexors and between the frequency of using techniques during groundwork and torques measured in hip extensors. High correlation of fat-free mass index and relative elbow flexor torque was found. Conclusions: The relationship between body composition and frequency of techniques used in a tournament, and joint torques developed by athletes were found.

4

Behavioural and motivational factors of individual’s behaviour in emergency situations

Piwowarski J.

Rocznik Bezpieczeństwa Morskiego

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2016

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R. X cz. III

195--211

EN

In the presented research project we observed the influence of physical culture1 on the level of security culture2, on personality, behavioural and axiological determinants of individual’s functioning in the context of physical activity under threatening conditions. We focused on testing of a group of people who were trained to act in the roles closely professionally related to security, including to hand-to-hand combat. It was assumed that their personality will develop in the direction of specific characteristics associated with security culture and display these characteristics. Considering this issue we took a securitological perspective3 focusing in particular on the first (of three: mental, organizational and material) dimension of security culture. In the research we referred the issue of personality and normative modifications of behaviour4. We also touched on the subject of interpretation of people’s behaviour in the axiological categories which are essential for the full image of martial arts.