0000000001025045
AUTHOR
Susanne Jauhiainen
A hierarchical cluster analysis to determine whether injured runners exhibit similar kinematic gait patterns
Previous studies have suggested that runners can be subgrouped based on homogeneous gait patterns, however, no previous study has assessed the presence of such subgroups in a population of individuals across a wide variety of injuries. Therefore, the purpose of this study was to assess whether distinct subgroups with homogeneous running patterns can be identified among a large group of injured and healthy runners and whether identified subgroups are associated with specific injury location. Three‐dimensional kinematic data from 291 injured and healthy runners, representing both sexes and a wide range of ages (10‐66 years) was clustered using hierarchical cluster analysis. Cluster analysis r…
A Simple Cluster Validation Index with Maximal Coverage
Clustering is an unsupervised technique to detect general, distinct profiles from a given dataset. Similarly to the existence of various different clustering methods and algorithms, there exists many cluster validation methods and indices to suggest the number of clusters. The purpose of this paper is, firstly, to propose a new, simple internal cluster validation index. The index has a maximal coverage: also one cluster, i.e., lack of division of a dataset into disjoint subsets, can be detected. Secondly, the proposed index is compared to the available indices from five different packages implemented in R or Matlab to assess its utilizability. The comparison also suggests many interesting f…
Collecting and Using Students’ Digital Well-Being Data in Multidisciplinary Teaching
This article examines how students (N=198; aged 13 to 17) experienced the new methods for sensor-based learning in multidisciplinary teaching in lower and upper secondary education that combine the use of new sensor technology and learning from self-produced well-being data. The aim was to explore how students perceived new methods from the point of view of their learning and did the teaching methods provide new information that could promote their own well-being. We also aimed to find out how to collect digital well-being data from a large number of students and how the collected big data set can be utilized to predict school success from the students’ well-being data by using machine lear…
Comparison of Internal Clustering Validation Indices for Prototype-Based Clustering
Clustering is an unsupervised machine learning and pattern recognition method. In general, in addition to revealing hidden groups of similar observations and clusters, their number needs to be determined. Internal clustering validation indices estimate this number without any external information. The purpose of this article is to evaluate, empirically, characteristics of a representative set of internal clustering validation indices with many datasets. The prototype-based clustering framework includes multiple, classical and robust, statistical estimates of cluster location so that the overall setting of the paper is novel. General observations on the quality of validation indices and on t…
Knowledge discovery from physical activity
Tässä pro gradu -tutkielmassa käydään läpi Knowledge Discovery in Databases (KDD) -prosessi ja sen soveltamismahdollisuuksia fyysiseen aktiivisuuteen liittyvän datan kanssa. KDD-prosessi koostuu monesta eri vaiheesta, sisältäen esikäsittelyn, datan muunnoksen ja tiedonlouhinnan. Tässä tutkielmassa tiedonlouhinnan menetelmänä käytetään klusterointia, joka käydään läpi yksityiskohtaisesti. Vertailemme myös laajan joukon eri klusterointi indeksejä (CVAIs) sekä niiden eri toteutuksia k-means klusteroinnin kanssa ja esittelemme parhaat näistä yleisemmässä muodossa. Tutkielman empiirisessä osassa seitsemäsluokkalaisten koululaisten aktiivisuusdataa tutkitaan KDD-prosessia seuraten ja hyödyntäen m…
sj-pdf-1-ajs-10.1177_03635465221112095 – Supplemental material for Predicting ACL Injury Using Machine Learning on Data From an Extensive Screening Test Battery of 880 Female Elite Athletes
Supplemental material, sj-pdf-1-ajs-10.1177_03635465221112095 for Predicting ACL Injury Using Machine Learning on Data From an Extensive Screening Test Battery of 880 Female Elite Athletes by Susanne Jauhiainen, Jukka-Pekka Kauppi, Tron Krosshaug, Roald Bahr, Julia Bartsch and Sami Äyrämö in The American Journal of Sports Medicine
Talent identification in soccer using a one-class support vector machine
Abstract Identifying potential future elite athletes is important in many sporting events. The successful identification of potential future elite athletes at an early age would help to provide high-quality coaching and training environments in which to optimize their development. However, a large variety of different skills and qualities are needed to succeed in elite sports, making talent identification generally a complex and multifaceted problem. Due to the rarity of elite athletes, datasets are inherently imbalanced, making classical statistical inference difficult. Therefore, we approach talent identification as an anomaly detection problem. We trained a nonlinear one-class support ve…
Comparison of feature importance measures as explanations for classification models
AbstractExplainable artificial intelligence is an emerging research direction helping the user or developer of machine learning models understand why models behave the way they do. The most popular explanation technique is feature importance. However, there are several different approaches how feature importances are being measured, most notably global and local. In this study we compare different feature importance measures using both linear (logistic regression with L1 penalization) and non-linear (random forest) methods and local interpretable model-agnostic explanations on top of them. These methods are applied to two datasets from the medical domain, the openly available breast cancer …
Poissonin yhtälön nopeat ratkaisijat
Tutkielmassa esitellään Poissonin yhtälö sekä sen diskretointi. Lisäksi käydään läpi kaksi nopeaa numeerista menetelmää yhtälön ratkaisemiseksi. Yksinkertaisuuden vuoksi rajoitutaan kaksiulotteisiin tehtäviin, joissa on voimassa Dirichle’t reunaehto. Ensimmäinen menetelmistä on monihilamenetelmä, joka on iteratiivinen menetelmä, ja toisena syklinen reduktio, joka on suora menetelmä. Molemmat menetelmät ovat hyvin tehokkaita sekä helposti rinnakkaistuvia. In this thesis we introduce Poisson’s equation and its discretization. In addition we go through two fast numerical methods for solving the equation. The thesis is limited only to two-dimensional cases with Dirichlet boundary condition. The…
Predicting ACL Injury Using Machine Learning on Data From an Extensive Screening Test Battery of 880 Female Elite Athletes
Background: Injury risk prediction is an emerging field in which more research is needed to recognize the best practices for accurate injury risk assessment. Important issues related to predictive machine learning need to be considered, for example, to avoid overinterpreting the observed prediction performance. Purpose: To carefully investigate the predictive potential of multiple predictive machine learning methods on a large set of risk factor data for anterior cruciate ligament (ACL) injury; the proposed approach takes into account the effect of chance and random variations in prediction performance. Study Design: Case-control study; Level of evidence, 3. Methods: The authors used 3-dime…
Information Extraction from Binary Skill Assessment Data with Machine Learning
Strength training exercises are essential for rehabilitation, improving our health as well as in sports. For optimal and safe training, educators and trainers in the industry should comprehend exercise form or technique. Currently, there is a lack of tools measuring in-depth skills of strength training experts. In this study, we investigate how data mining methods can be used to identify novel and useful skill patterns from a binary multiple choice questionnaire test designed to measure the knowledge level of strength training experts. A skill test assessing exercise technique expertise and comprehension was answered by 507 fitness professionals with varying backgrounds. A triangulated appr…